diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/i2c/i2c-core-base.c | 2530 |
1 files changed, 2530 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c new file mode 100644 index 000000000..5e3976ba5 --- /dev/null +++ b/drivers/i2c/i2c-core-base.c @@ -0,0 +1,2530 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Linux I2C core + * + * Copyright (C) 1995-99 Simon G. Vogl + * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> + * Mux support by Rodolfo Giometti <giometti@enneenne.com> and + * Michael Lawnick <michael.lawnick.ext@nsn.com> + * + * Copyright (C) 2013-2017 Wolfram Sang <wsa@kernel.org> + */ + +#define pr_fmt(fmt) "i2c-core: " fmt + +#include <dt-bindings/i2c/i2c.h> +#include <linux/acpi.h> +#include <linux/clk/clk-conf.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/i2c-smbus.h> +#include <linux/idr.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/irqflags.h> +#include <linux/jump_label.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of_device.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/pinctrl/consumer.h> +#include <linux/pm_domain.h> +#include <linux/pm_runtime.h> +#include <linux/pm_wakeirq.h> +#include <linux/property.h> +#include <linux/rwsem.h> +#include <linux/slab.h> + +#include "i2c-core.h" + +#define CREATE_TRACE_POINTS +#include <trace/events/i2c.h> + +#define I2C_ADDR_OFFSET_TEN_BIT 0xa000 +#define I2C_ADDR_OFFSET_SLAVE 0x1000 + +#define I2C_ADDR_7BITS_MAX 0x77 +#define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1) + +#define I2C_ADDR_DEVICE_ID 0x7c + +/* + * core_lock protects i2c_adapter_idr, and guarantees that device detection, + * deletion of detected devices are serialized + */ +static DEFINE_MUTEX(core_lock); +static DEFINE_IDR(i2c_adapter_idr); + +static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); + +static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key); +static bool is_registered; + +int i2c_transfer_trace_reg(void) +{ + static_branch_inc(&i2c_trace_msg_key); + return 0; +} + +void i2c_transfer_trace_unreg(void) +{ + static_branch_dec(&i2c_trace_msg_key); +} + +const char *i2c_freq_mode_string(u32 bus_freq_hz) +{ + switch (bus_freq_hz) { + case I2C_MAX_STANDARD_MODE_FREQ: + return "Standard Mode (100 kHz)"; + case I2C_MAX_FAST_MODE_FREQ: + return "Fast Mode (400 kHz)"; + case I2C_MAX_FAST_MODE_PLUS_FREQ: + return "Fast Mode Plus (1.0 MHz)"; + case I2C_MAX_TURBO_MODE_FREQ: + return "Turbo Mode (1.4 MHz)"; + case I2C_MAX_HIGH_SPEED_MODE_FREQ: + return "High Speed Mode (3.4 MHz)"; + case I2C_MAX_ULTRA_FAST_MODE_FREQ: + return "Ultra Fast Mode (5.0 MHz)"; + default: + return "Unknown Mode"; + } +} +EXPORT_SYMBOL_GPL(i2c_freq_mode_string); + +const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id, + const struct i2c_client *client) +{ + if (!(id && client)) + return NULL; + + while (id->name[0]) { + if (strcmp(client->name, id->name) == 0) + return id; + id++; + } + return NULL; +} +EXPORT_SYMBOL_GPL(i2c_match_id); + +static int i2c_device_match(struct device *dev, struct device_driver *drv) +{ + struct i2c_client *client = i2c_verify_client(dev); + struct i2c_driver *driver; + + + /* Attempt an OF style match */ + if (i2c_of_match_device(drv->of_match_table, client)) + return 1; + + /* Then ACPI style match */ + if (acpi_driver_match_device(dev, drv)) + return 1; + + driver = to_i2c_driver(drv); + + /* Finally an I2C match */ + if (i2c_match_id(driver->id_table, client)) + return 1; + + return 0; +} + +static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env) +{ + struct i2c_client *client = to_i2c_client(dev); + int rc; + + rc = of_device_uevent_modalias(dev, env); + if (rc != -ENODEV) + return rc; + + rc = acpi_device_uevent_modalias(dev, env); + if (rc != -ENODEV) + return rc; + + return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name); +} + +/* i2c bus recovery routines */ +static int get_scl_gpio_value(struct i2c_adapter *adap) +{ + return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod); +} + +static void set_scl_gpio_value(struct i2c_adapter *adap, int val) +{ + gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val); +} + +static int get_sda_gpio_value(struct i2c_adapter *adap) +{ + return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod); +} + +static void set_sda_gpio_value(struct i2c_adapter *adap, int val) +{ + gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val); +} + +static int i2c_generic_bus_free(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + int ret = -EOPNOTSUPP; + + if (bri->get_bus_free) + ret = bri->get_bus_free(adap); + else if (bri->get_sda) + ret = bri->get_sda(adap); + + if (ret < 0) + return ret; + + return ret ? 0 : -EBUSY; +} + +/* + * We are generating clock pulses. ndelay() determines durating of clk pulses. + * We will generate clock with rate 100 KHz and so duration of both clock levels + * is: delay in ns = (10^6 / 100) / 2 + */ +#define RECOVERY_NDELAY 5000 +#define RECOVERY_CLK_CNT 9 + +int i2c_generic_scl_recovery(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + int i = 0, scl = 1, ret = 0; + + if (bri->prepare_recovery) + bri->prepare_recovery(adap); + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_gpio); + + /* + * If we can set SDA, we will always create a STOP to ensure additional + * pulses will do no harm. This is achieved by letting SDA follow SCL + * half a cycle later. Check the 'incomplete_write_byte' fault injector + * for details. Note that we must honour tsu:sto, 4us, but lets use 5us + * here for simplicity. + */ + bri->set_scl(adap, scl); + ndelay(RECOVERY_NDELAY); + if (bri->set_sda) + bri->set_sda(adap, scl); + ndelay(RECOVERY_NDELAY / 2); + + /* + * By this time SCL is high, as we need to give 9 falling-rising edges + */ + while (i++ < RECOVERY_CLK_CNT * 2) { + if (scl) { + /* SCL shouldn't be low here */ + if (!bri->get_scl(adap)) { + dev_err(&adap->dev, + "SCL is stuck low, exit recovery\n"); + ret = -EBUSY; + break; + } + } + + scl = !scl; + bri->set_scl(adap, scl); + /* Creating STOP again, see above */ + if (scl) { + /* Honour minimum tsu:sto */ + ndelay(RECOVERY_NDELAY); + } else { + /* Honour minimum tf and thd:dat */ + ndelay(RECOVERY_NDELAY / 2); + } + if (bri->set_sda) + bri->set_sda(adap, scl); + ndelay(RECOVERY_NDELAY / 2); + + if (scl) { + ret = i2c_generic_bus_free(adap); + if (ret == 0) + break; + } + } + + /* If we can't check bus status, assume recovery worked */ + if (ret == -EOPNOTSUPP) + ret = 0; + + if (bri->unprepare_recovery) + bri->unprepare_recovery(adap); + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_default); + + return ret; +} +EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery); + +int i2c_recover_bus(struct i2c_adapter *adap) +{ + if (!adap->bus_recovery_info) + return -EBUSY; + + dev_dbg(&adap->dev, "Trying i2c bus recovery\n"); + return adap->bus_recovery_info->recover_bus(adap); +} +EXPORT_SYMBOL_GPL(i2c_recover_bus); + +static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + struct device *dev = &adap->dev; + struct pinctrl *p = bri->pinctrl; + + /* + * we can't change states without pinctrl, so remove the states if + * populated + */ + if (!p) { + bri->pins_default = NULL; + bri->pins_gpio = NULL; + return; + } + + if (!bri->pins_default) { + bri->pins_default = pinctrl_lookup_state(p, + PINCTRL_STATE_DEFAULT); + if (IS_ERR(bri->pins_default)) { + dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n"); + bri->pins_default = NULL; + } + } + if (!bri->pins_gpio) { + bri->pins_gpio = pinctrl_lookup_state(p, "gpio"); + if (IS_ERR(bri->pins_gpio)) + bri->pins_gpio = pinctrl_lookup_state(p, "recovery"); + + if (IS_ERR(bri->pins_gpio)) { + dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n"); + bri->pins_gpio = NULL; + } + } + + /* for pinctrl state changes, we need all the information */ + if (bri->pins_default && bri->pins_gpio) { + dev_info(dev, "using pinctrl states for GPIO recovery"); + } else { + bri->pinctrl = NULL; + bri->pins_default = NULL; + bri->pins_gpio = NULL; + } +} + +static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + struct device *dev = &adap->dev; + struct gpio_desc *gpiod; + int ret = 0; + + /* + * don't touch the recovery information if the driver is not using + * generic SCL recovery + */ + if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery) + return 0; + + /* + * pins might be taken as GPIO, so we should inform pinctrl about + * this and move the state to GPIO + */ + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_gpio); + + /* + * if there is incomplete or no recovery information, see if generic + * GPIO recovery is available + */ + if (!bri->scl_gpiod) { + gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN); + if (PTR_ERR(gpiod) == -EPROBE_DEFER) { + ret = -EPROBE_DEFER; + goto cleanup_pinctrl_state; + } + if (!IS_ERR(gpiod)) { + bri->scl_gpiod = gpiod; + bri->recover_bus = i2c_generic_scl_recovery; + dev_info(dev, "using generic GPIOs for recovery\n"); + } + } + + /* SDA GPIOD line is optional, so we care about DEFER only */ + if (!bri->sda_gpiod) { + /* + * We have SCL. Pull SCL low and wait a bit so that SDA glitches + * have no effect. + */ + gpiod_direction_output(bri->scl_gpiod, 0); + udelay(10); + gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN); + + /* Wait a bit in case of a SDA glitch, and then release SCL. */ + udelay(10); + gpiod_direction_output(bri->scl_gpiod, 1); + + if (PTR_ERR(gpiod) == -EPROBE_DEFER) { + ret = -EPROBE_DEFER; + goto cleanup_pinctrl_state; + } + if (!IS_ERR(gpiod)) + bri->sda_gpiod = gpiod; + } + +cleanup_pinctrl_state: + /* change the state of the pins back to their default state */ + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_default); + + return ret; +} + +static int i2c_gpio_init_recovery(struct i2c_adapter *adap) +{ + i2c_gpio_init_pinctrl_recovery(adap); + return i2c_gpio_init_generic_recovery(adap); +} + +static int i2c_init_recovery(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + bool is_error_level = true; + char *err_str; + + if (!bri) + return 0; + + if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER) + return -EPROBE_DEFER; + + if (!bri->recover_bus) { + err_str = "no suitable method provided"; + is_error_level = false; + goto err; + } + + if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) { + bri->get_scl = get_scl_gpio_value; + bri->set_scl = set_scl_gpio_value; + if (bri->sda_gpiod) { + bri->get_sda = get_sda_gpio_value; + /* FIXME: add proper flag instead of '0' once available */ + if (gpiod_get_direction(bri->sda_gpiod) == 0) + bri->set_sda = set_sda_gpio_value; + } + } else if (bri->recover_bus == i2c_generic_scl_recovery) { + /* Generic SCL recovery */ + if (!bri->set_scl || !bri->get_scl) { + err_str = "no {get|set}_scl() found"; + goto err; + } + if (!bri->set_sda && !bri->get_sda) { + err_str = "either get_sda() or set_sda() needed"; + goto err; + } + } + + return 0; + err: + if (is_error_level) + dev_err(&adap->dev, "Not using recovery: %s\n", err_str); + else + dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str); + adap->bus_recovery_info = NULL; + + return -EINVAL; +} + +static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client) +{ + struct i2c_adapter *adap = client->adapter; + unsigned int irq; + + if (!adap->host_notify_domain) + return -ENXIO; + + if (client->flags & I2C_CLIENT_TEN) + return -EINVAL; + + irq = irq_create_mapping(adap->host_notify_domain, client->addr); + + return irq > 0 ? irq : -ENXIO; +} + +static int i2c_device_probe(struct device *dev) +{ + struct i2c_client *client = i2c_verify_client(dev); + struct i2c_driver *driver; + bool do_power_on; + int status; + + if (!client) + return 0; + + client->irq = client->init_irq; + + if (!client->irq) { + int irq = -ENOENT; + + if (client->flags & I2C_CLIENT_HOST_NOTIFY) { + dev_dbg(dev, "Using Host Notify IRQ\n"); + /* Keep adapter active when Host Notify is required */ + pm_runtime_get_sync(&client->adapter->dev); + irq = i2c_smbus_host_notify_to_irq(client); + } else if (dev->of_node) { + irq = of_irq_get_byname(dev->of_node, "irq"); + if (irq == -EINVAL || irq == -ENODATA) + irq = of_irq_get(dev->of_node, 0); + } else if (ACPI_COMPANION(dev)) { + bool wake_capable; + + irq = i2c_acpi_get_irq(client, &wake_capable); + if (irq > 0 && wake_capable) + client->flags |= I2C_CLIENT_WAKE; + } + if (irq == -EPROBE_DEFER) { + status = irq; + goto put_sync_adapter; + } + + if (irq < 0) + irq = 0; + + client->irq = irq; + } + + driver = to_i2c_driver(dev->driver); + + /* + * An I2C ID table is not mandatory, if and only if, a suitable OF + * or ACPI ID table is supplied for the probing device. + */ + if (!driver->id_table && + !acpi_driver_match_device(dev, dev->driver) && + !i2c_of_match_device(dev->driver->of_match_table, client)) { + status = -ENODEV; + goto put_sync_adapter; + } + + if (client->flags & I2C_CLIENT_WAKE) { + int wakeirq; + + wakeirq = of_irq_get_byname(dev->of_node, "wakeup"); + if (wakeirq == -EPROBE_DEFER) { + status = wakeirq; + goto put_sync_adapter; + } + + device_init_wakeup(&client->dev, true); + + if (wakeirq > 0 && wakeirq != client->irq) + status = dev_pm_set_dedicated_wake_irq(dev, wakeirq); + else if (client->irq > 0) + status = dev_pm_set_wake_irq(dev, client->irq); + else + status = 0; + + if (status) + dev_warn(&client->dev, "failed to set up wakeup irq\n"); + } + + dev_dbg(dev, "probe\n"); + + status = of_clk_set_defaults(dev->of_node, false); + if (status < 0) + goto err_clear_wakeup_irq; + + do_power_on = !i2c_acpi_waive_d0_probe(dev); + status = dev_pm_domain_attach(&client->dev, do_power_on); + if (status) + goto err_clear_wakeup_irq; + + client->devres_group_id = devres_open_group(&client->dev, NULL, + GFP_KERNEL); + if (!client->devres_group_id) { + status = -ENOMEM; + goto err_detach_pm_domain; + } + + /* + * When there are no more users of probe(), + * rename probe_new to probe. + */ + if (driver->probe_new) + status = driver->probe_new(client); + else if (driver->probe) + status = driver->probe(client, + i2c_match_id(driver->id_table, client)); + else + status = -EINVAL; + + /* + * Note that we are not closing the devres group opened above so + * even resources that were attached to the device after probe is + * run are released when i2c_device_remove() is executed. This is + * needed as some drivers would allocate additional resources, + * for example when updating firmware. + */ + + if (status) + goto err_release_driver_resources; + + return 0; + +err_release_driver_resources: + devres_release_group(&client->dev, client->devres_group_id); +err_detach_pm_domain: + dev_pm_domain_detach(&client->dev, do_power_on); +err_clear_wakeup_irq: + dev_pm_clear_wake_irq(&client->dev); + device_init_wakeup(&client->dev, false); +put_sync_adapter: + if (client->flags & I2C_CLIENT_HOST_NOTIFY) + pm_runtime_put_sync(&client->adapter->dev); + + return status; +} + +static void i2c_device_remove(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + struct i2c_driver *driver; + + driver = to_i2c_driver(dev->driver); + if (driver->remove) { + dev_dbg(dev, "remove\n"); + + driver->remove(client); + } + + devres_release_group(&client->dev, client->devres_group_id); + + dev_pm_domain_detach(&client->dev, true); + + dev_pm_clear_wake_irq(&client->dev); + device_init_wakeup(&client->dev, false); + + client->irq = 0; + if (client->flags & I2C_CLIENT_HOST_NOTIFY) + pm_runtime_put(&client->adapter->dev); +} + +static void i2c_device_shutdown(struct device *dev) +{ + struct i2c_client *client = i2c_verify_client(dev); + struct i2c_driver *driver; + + if (!client || !dev->driver) + return; + driver = to_i2c_driver(dev->driver); + if (driver->shutdown) + driver->shutdown(client); + else if (client->irq > 0) + disable_irq(client->irq); +} + +static void i2c_client_dev_release(struct device *dev) +{ + kfree(to_i2c_client(dev)); +} + +static ssize_t +name_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%s\n", dev->type == &i2c_client_type ? + to_i2c_client(dev)->name : to_i2c_adapter(dev)->name); +} +static DEVICE_ATTR_RO(name); + +static ssize_t +modalias_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + int len; + + len = of_device_modalias(dev, buf, PAGE_SIZE); + if (len != -ENODEV) + return len; + + len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1); + if (len != -ENODEV) + return len; + + return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name); +} +static DEVICE_ATTR_RO(modalias); + +static struct attribute *i2c_dev_attrs[] = { + &dev_attr_name.attr, + /* modalias helps coldplug: modprobe $(cat .../modalias) */ + &dev_attr_modalias.attr, + NULL +}; +ATTRIBUTE_GROUPS(i2c_dev); + +struct bus_type i2c_bus_type = { + .name = "i2c", + .match = i2c_device_match, + .probe = i2c_device_probe, + .remove = i2c_device_remove, + .shutdown = i2c_device_shutdown, +}; +EXPORT_SYMBOL_GPL(i2c_bus_type); + +struct device_type i2c_client_type = { + .groups = i2c_dev_groups, + .uevent = i2c_device_uevent, + .release = i2c_client_dev_release, +}; +EXPORT_SYMBOL_GPL(i2c_client_type); + + +/** + * i2c_verify_client - return parameter as i2c_client, or NULL + * @dev: device, probably from some driver model iterator + * + * When traversing the driver model tree, perhaps using driver model + * iterators like @device_for_each_child(), you can't assume very much + * about the nodes you find. Use this function to avoid oopses caused + * by wrongly treating some non-I2C device as an i2c_client. + */ +struct i2c_client *i2c_verify_client(struct device *dev) +{ + return (dev->type == &i2c_client_type) + ? to_i2c_client(dev) + : NULL; +} +EXPORT_SYMBOL(i2c_verify_client); + + +/* Return a unique address which takes the flags of the client into account */ +static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client) +{ + unsigned short addr = client->addr; + + /* For some client flags, add an arbitrary offset to avoid collisions */ + if (client->flags & I2C_CLIENT_TEN) + addr |= I2C_ADDR_OFFSET_TEN_BIT; + + if (client->flags & I2C_CLIENT_SLAVE) + addr |= I2C_ADDR_OFFSET_SLAVE; + + return addr; +} + +/* This is a permissive address validity check, I2C address map constraints + * are purposely not enforced, except for the general call address. */ +static int i2c_check_addr_validity(unsigned int addr, unsigned short flags) +{ + if (flags & I2C_CLIENT_TEN) { + /* 10-bit address, all values are valid */ + if (addr > 0x3ff) + return -EINVAL; + } else { + /* 7-bit address, reject the general call address */ + if (addr == 0x00 || addr > 0x7f) + return -EINVAL; + } + return 0; +} + +/* And this is a strict address validity check, used when probing. If a + * device uses a reserved address, then it shouldn't be probed. 7-bit + * addressing is assumed, 10-bit address devices are rare and should be + * explicitly enumerated. */ +int i2c_check_7bit_addr_validity_strict(unsigned short addr) +{ + /* + * Reserved addresses per I2C specification: + * 0x00 General call address / START byte + * 0x01 CBUS address + * 0x02 Reserved for different bus format + * 0x03 Reserved for future purposes + * 0x04-0x07 Hs-mode master code + * 0x78-0x7b 10-bit slave addressing + * 0x7c-0x7f Reserved for future purposes + */ + if (addr < 0x08 || addr > 0x77) + return -EINVAL; + return 0; +} + +static int __i2c_check_addr_busy(struct device *dev, void *addrp) +{ + struct i2c_client *client = i2c_verify_client(dev); + int addr = *(int *)addrp; + + if (client && i2c_encode_flags_to_addr(client) == addr) + return -EBUSY; + return 0; +} + +/* walk up mux tree */ +static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr) +{ + struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); + int result; + + result = device_for_each_child(&adapter->dev, &addr, + __i2c_check_addr_busy); + + if (!result && parent) + result = i2c_check_mux_parents(parent, addr); + + return result; +} + +/* recurse down mux tree */ +static int i2c_check_mux_children(struct device *dev, void *addrp) +{ + int result; + + if (dev->type == &i2c_adapter_type) + result = device_for_each_child(dev, addrp, + i2c_check_mux_children); + else + result = __i2c_check_addr_busy(dev, addrp); + + return result; +} + +static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) +{ + struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); + int result = 0; + + if (parent) + result = i2c_check_mux_parents(parent, addr); + + if (!result) + result = device_for_each_child(&adapter->dev, &addr, + i2c_check_mux_children); + + return result; +} + +/** + * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment + * @adapter: Target I2C bus segment + * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT + * locks only this branch in the adapter tree + */ +static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, + unsigned int flags) +{ + rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter)); +} + +/** + * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment + * @adapter: Target I2C bus segment + * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT + * trylocks only this branch in the adapter tree + */ +static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter, + unsigned int flags) +{ + return rt_mutex_trylock(&adapter->bus_lock); +} + +/** + * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment + * @adapter: Target I2C bus segment + * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT + * unlocks only this branch in the adapter tree + */ +static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter, + unsigned int flags) +{ + rt_mutex_unlock(&adapter->bus_lock); +} + +static void i2c_dev_set_name(struct i2c_adapter *adap, + struct i2c_client *client, + struct i2c_board_info const *info) +{ + struct acpi_device *adev = ACPI_COMPANION(&client->dev); + + if (info && info->dev_name) { + dev_set_name(&client->dev, "i2c-%s", info->dev_name); + return; + } + + if (adev) { + dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev)); + return; + } + + dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap), + i2c_encode_flags_to_addr(client)); +} + +int i2c_dev_irq_from_resources(const struct resource *resources, + unsigned int num_resources) +{ + struct irq_data *irqd; + int i; + + for (i = 0; i < num_resources; i++) { + const struct resource *r = &resources[i]; + + if (resource_type(r) != IORESOURCE_IRQ) + continue; + + if (r->flags & IORESOURCE_BITS) { + irqd = irq_get_irq_data(r->start); + if (!irqd) + break; + + irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); + } + + return r->start; + } + + return 0; +} + +/** + * i2c_new_client_device - instantiate an i2c device + * @adap: the adapter managing the device + * @info: describes one I2C device; bus_num is ignored + * Context: can sleep + * + * Create an i2c device. Binding is handled through driver model + * probe()/remove() methods. A driver may be bound to this device when we + * return from this function, or any later moment (e.g. maybe hotplugging will + * load the driver module). This call is not appropriate for use by mainboard + * initialization logic, which usually runs during an arch_initcall() long + * before any i2c_adapter could exist. + * + * This returns the new i2c client, which may be saved for later use with + * i2c_unregister_device(); or an ERR_PTR to describe the error. + */ +struct i2c_client * +i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info) +{ + struct i2c_client *client; + bool need_put = false; + int status; + + client = kzalloc(sizeof *client, GFP_KERNEL); + if (!client) + return ERR_PTR(-ENOMEM); + + client->adapter = adap; + + client->dev.platform_data = info->platform_data; + client->flags = info->flags; + client->addr = info->addr; + + client->init_irq = info->irq; + if (!client->init_irq) + client->init_irq = i2c_dev_irq_from_resources(info->resources, + info->num_resources); + + strscpy(client->name, info->type, sizeof(client->name)); + + status = i2c_check_addr_validity(client->addr, client->flags); + if (status) { + dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n", + client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr); + goto out_err_silent; + } + + /* Check for address business */ + status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client)); + if (status) + goto out_err; + + client->dev.parent = &client->adapter->dev; + client->dev.bus = &i2c_bus_type; + client->dev.type = &i2c_client_type; + client->dev.of_node = of_node_get(info->of_node); + client->dev.fwnode = info->fwnode; + + device_enable_async_suspend(&client->dev); + + if (info->swnode) { + status = device_add_software_node(&client->dev, info->swnode); + if (status) { + dev_err(&adap->dev, + "Failed to add software node to client %s: %d\n", + client->name, status); + goto out_err_put_of_node; + } + } + + i2c_dev_set_name(adap, client, info); + status = device_register(&client->dev); + if (status) + goto out_remove_swnode; + + dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", + client->name, dev_name(&client->dev)); + + return client; + +out_remove_swnode: + device_remove_software_node(&client->dev); + need_put = true; +out_err_put_of_node: + of_node_put(info->of_node); +out_err: + dev_err(&adap->dev, + "Failed to register i2c client %s at 0x%02x (%d)\n", + client->name, client->addr, status); +out_err_silent: + if (need_put) + put_device(&client->dev); + else + kfree(client); + return ERR_PTR(status); +} +EXPORT_SYMBOL_GPL(i2c_new_client_device); + +/** + * i2c_unregister_device - reverse effect of i2c_new_*_device() + * @client: value returned from i2c_new_*_device() + * Context: can sleep + */ +void i2c_unregister_device(struct i2c_client *client) +{ + if (IS_ERR_OR_NULL(client)) + return; + + if (client->dev.of_node) { + of_node_clear_flag(client->dev.of_node, OF_POPULATED); + of_node_put(client->dev.of_node); + } + + if (ACPI_COMPANION(&client->dev)) + acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev)); + device_remove_software_node(&client->dev); + device_unregister(&client->dev); +} +EXPORT_SYMBOL_GPL(i2c_unregister_device); + + +static const struct i2c_device_id dummy_id[] = { + { "dummy", 0 }, + { }, +}; + +static int dummy_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + return 0; +} + +static struct i2c_driver dummy_driver = { + .driver.name = "dummy", + .probe = dummy_probe, + .id_table = dummy_id, +}; + +/** + * i2c_new_dummy_device - return a new i2c device bound to a dummy driver + * @adapter: the adapter managing the device + * @address: seven bit address to be used + * Context: can sleep + * + * This returns an I2C client bound to the "dummy" driver, intended for use + * with devices that consume multiple addresses. Examples of such chips + * include various EEPROMS (like 24c04 and 24c08 models). + * + * These dummy devices have two main uses. First, most I2C and SMBus calls + * except i2c_transfer() need a client handle; the dummy will be that handle. + * And second, this prevents the specified address from being bound to a + * different driver. + * + * This returns the new i2c client, which should be saved for later use with + * i2c_unregister_device(); or an ERR_PTR to describe the error. + */ +struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address) +{ + struct i2c_board_info info = { + I2C_BOARD_INFO("dummy", address), + }; + + return i2c_new_client_device(adapter, &info); +} +EXPORT_SYMBOL_GPL(i2c_new_dummy_device); + +static void devm_i2c_release_dummy(void *client) +{ + i2c_unregister_device(client); +} + +/** + * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver + * @dev: device the managed resource is bound to + * @adapter: the adapter managing the device + * @address: seven bit address to be used + * Context: can sleep + * + * This is the device-managed version of @i2c_new_dummy_device. It returns the + * new i2c client or an ERR_PTR in case of an error. + */ +struct i2c_client *devm_i2c_new_dummy_device(struct device *dev, + struct i2c_adapter *adapter, + u16 address) +{ + struct i2c_client *client; + int ret; + + client = i2c_new_dummy_device(adapter, address); + if (IS_ERR(client)) + return client; + + ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client); + if (ret) + return ERR_PTR(ret); + + return client; +} +EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device); + +/** + * i2c_new_ancillary_device - Helper to get the instantiated secondary address + * and create the associated device + * @client: Handle to the primary client + * @name: Handle to specify which secondary address to get + * @default_addr: Used as a fallback if no secondary address was specified + * Context: can sleep + * + * I2C clients can be composed of multiple I2C slaves bound together in a single + * component. The I2C client driver then binds to the master I2C slave and needs + * to create I2C dummy clients to communicate with all the other slaves. + * + * This function creates and returns an I2C dummy client whose I2C address is + * retrieved from the platform firmware based on the given slave name. If no + * address is specified by the firmware default_addr is used. + * + * On DT-based platforms the address is retrieved from the "reg" property entry + * cell whose "reg-names" value matches the slave name. + * + * This returns the new i2c client, which should be saved for later use with + * i2c_unregister_device(); or an ERR_PTR to describe the error. + */ +struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, + const char *name, + u16 default_addr) +{ + struct device_node *np = client->dev.of_node; + u32 addr = default_addr; + int i; + + if (np) { + i = of_property_match_string(np, "reg-names", name); + if (i >= 0) + of_property_read_u32_index(np, "reg", i, &addr); + } + + dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); + return i2c_new_dummy_device(client->adapter, addr); +} +EXPORT_SYMBOL_GPL(i2c_new_ancillary_device); + +/* ------------------------------------------------------------------------- */ + +/* I2C bus adapters -- one roots each I2C or SMBUS segment */ + +static void i2c_adapter_dev_release(struct device *dev) +{ + struct i2c_adapter *adap = to_i2c_adapter(dev); + complete(&adap->dev_released); +} + +unsigned int i2c_adapter_depth(struct i2c_adapter *adapter) +{ + unsigned int depth = 0; + + while ((adapter = i2c_parent_is_i2c_adapter(adapter))) + depth++; + + WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES, + "adapter depth exceeds lockdep subclass limit\n"); + + return depth; +} +EXPORT_SYMBOL_GPL(i2c_adapter_depth); + +/* + * Let users instantiate I2C devices through sysfs. This can be used when + * platform initialization code doesn't contain the proper data for + * whatever reason. Also useful for drivers that do device detection and + * detection fails, either because the device uses an unexpected address, + * or this is a compatible device with different ID register values. + * + * Parameter checking may look overzealous, but we really don't want + * the user to provide incorrect parameters. + */ +static ssize_t +new_device_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct i2c_adapter *adap = to_i2c_adapter(dev); + struct i2c_board_info info; + struct i2c_client *client; + char *blank, end; + int res; + + memset(&info, 0, sizeof(struct i2c_board_info)); + + blank = strchr(buf, ' '); + if (!blank) { + dev_err(dev, "%s: Missing parameters\n", "new_device"); + return -EINVAL; + } + if (blank - buf > I2C_NAME_SIZE - 1) { + dev_err(dev, "%s: Invalid device name\n", "new_device"); + return -EINVAL; + } + memcpy(info.type, buf, blank - buf); + + /* Parse remaining parameters, reject extra parameters */ + res = sscanf(++blank, "%hi%c", &info.addr, &end); + if (res < 1) { + dev_err(dev, "%s: Can't parse I2C address\n", "new_device"); + return -EINVAL; + } + if (res > 1 && end != '\n') { + dev_err(dev, "%s: Extra parameters\n", "new_device"); + return -EINVAL; + } + + if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) { + info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT; + info.flags |= I2C_CLIENT_TEN; + } + + if (info.addr & I2C_ADDR_OFFSET_SLAVE) { + info.addr &= ~I2C_ADDR_OFFSET_SLAVE; + info.flags |= I2C_CLIENT_SLAVE; + } + + client = i2c_new_client_device(adap, &info); + if (IS_ERR(client)) + return PTR_ERR(client); + + /* Keep track of the added device */ + mutex_lock(&adap->userspace_clients_lock); + list_add_tail(&client->detected, &adap->userspace_clients); + mutex_unlock(&adap->userspace_clients_lock); + dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device", + info.type, info.addr); + + return count; +} +static DEVICE_ATTR_WO(new_device); + +/* + * And of course let the users delete the devices they instantiated, if + * they got it wrong. This interface can only be used to delete devices + * instantiated by i2c_sysfs_new_device above. This guarantees that we + * don't delete devices to which some kernel code still has references. + * + * Parameter checking may look overzealous, but we really don't want + * the user to delete the wrong device. + */ +static ssize_t +delete_device_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct i2c_adapter *adap = to_i2c_adapter(dev); + struct i2c_client *client, *next; + unsigned short addr; + char end; + int res; + + /* Parse parameters, reject extra parameters */ + res = sscanf(buf, "%hi%c", &addr, &end); + if (res < 1) { + dev_err(dev, "%s: Can't parse I2C address\n", "delete_device"); + return -EINVAL; + } + if (res > 1 && end != '\n') { + dev_err(dev, "%s: Extra parameters\n", "delete_device"); + return -EINVAL; + } + + /* Make sure the device was added through sysfs */ + res = -ENOENT; + mutex_lock_nested(&adap->userspace_clients_lock, + i2c_adapter_depth(adap)); + list_for_each_entry_safe(client, next, &adap->userspace_clients, + detected) { + if (i2c_encode_flags_to_addr(client) == addr) { + dev_info(dev, "%s: Deleting device %s at 0x%02hx\n", + "delete_device", client->name, client->addr); + + list_del(&client->detected); + i2c_unregister_device(client); + res = count; + break; + } + } + mutex_unlock(&adap->userspace_clients_lock); + + if (res < 0) + dev_err(dev, "%s: Can't find device in list\n", + "delete_device"); + return res; +} +static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL, + delete_device_store); + +static struct attribute *i2c_adapter_attrs[] = { + &dev_attr_name.attr, + &dev_attr_new_device.attr, + &dev_attr_delete_device.attr, + NULL +}; +ATTRIBUTE_GROUPS(i2c_adapter); + +struct device_type i2c_adapter_type = { + .groups = i2c_adapter_groups, + .release = i2c_adapter_dev_release, +}; +EXPORT_SYMBOL_GPL(i2c_adapter_type); + +/** + * i2c_verify_adapter - return parameter as i2c_adapter or NULL + * @dev: device, probably from some driver model iterator + * + * When traversing the driver model tree, perhaps using driver model + * iterators like @device_for_each_child(), you can't assume very much + * about the nodes you find. Use this function to avoid oopses caused + * by wrongly treating some non-I2C device as an i2c_adapter. + */ +struct i2c_adapter *i2c_verify_adapter(struct device *dev) +{ + return (dev->type == &i2c_adapter_type) + ? to_i2c_adapter(dev) + : NULL; +} +EXPORT_SYMBOL(i2c_verify_adapter); + +#ifdef CONFIG_I2C_COMPAT +static struct class_compat *i2c_adapter_compat_class; +#endif + +static void i2c_scan_static_board_info(struct i2c_adapter *adapter) +{ + struct i2c_devinfo *devinfo; + + down_read(&__i2c_board_lock); + list_for_each_entry(devinfo, &__i2c_board_list, list) { + if (devinfo->busnum == adapter->nr && + IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info))) + dev_err(&adapter->dev, + "Can't create device at 0x%02x\n", + devinfo->board_info.addr); + } + up_read(&__i2c_board_lock); +} + +static int i2c_do_add_adapter(struct i2c_driver *driver, + struct i2c_adapter *adap) +{ + /* Detect supported devices on that bus, and instantiate them */ + i2c_detect(adap, driver); + + return 0; +} + +static int __process_new_adapter(struct device_driver *d, void *data) +{ + return i2c_do_add_adapter(to_i2c_driver(d), data); +} + +static const struct i2c_lock_operations i2c_adapter_lock_ops = { + .lock_bus = i2c_adapter_lock_bus, + .trylock_bus = i2c_adapter_trylock_bus, + .unlock_bus = i2c_adapter_unlock_bus, +}; + +static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap) +{ + struct irq_domain *domain = adap->host_notify_domain; + irq_hw_number_t hwirq; + + if (!domain) + return; + + for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++) + irq_dispose_mapping(irq_find_mapping(domain, hwirq)); + + irq_domain_remove(domain); + adap->host_notify_domain = NULL; +} + +static int i2c_host_notify_irq_map(struct irq_domain *h, + unsigned int virq, + irq_hw_number_t hw_irq_num) +{ + irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq); + + return 0; +} + +static const struct irq_domain_ops i2c_host_notify_irq_ops = { + .map = i2c_host_notify_irq_map, +}; + +static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap) +{ + struct irq_domain *domain; + + if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY)) + return 0; + + domain = irq_domain_create_linear(adap->dev.parent->fwnode, + I2C_ADDR_7BITS_COUNT, + &i2c_host_notify_irq_ops, adap); + if (!domain) + return -ENOMEM; + + adap->host_notify_domain = domain; + + return 0; +} + +/** + * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct + * I2C client. + * @adap: the adapter + * @addr: the I2C address of the notifying device + * Context: can't sleep + * + * Helper function to be called from an I2C bus driver's interrupt + * handler. It will schedule the Host Notify IRQ. + */ +int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr) +{ + int irq; + + if (!adap) + return -EINVAL; + + irq = irq_find_mapping(adap->host_notify_domain, addr); + if (irq <= 0) + return -ENXIO; + + generic_handle_irq_safe(irq); + + return 0; +} +EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify); + +static int i2c_register_adapter(struct i2c_adapter *adap) +{ + int res = -EINVAL; + + /* Can't register until after driver model init */ + if (WARN_ON(!is_registered)) { + res = -EAGAIN; + goto out_list; + } + + /* Sanity checks */ + if (WARN(!adap->name[0], "i2c adapter has no name")) + goto out_list; + + if (!adap->algo) { + pr_err("adapter '%s': no algo supplied!\n", adap->name); + goto out_list; + } + + if (!adap->lock_ops) + adap->lock_ops = &i2c_adapter_lock_ops; + + adap->locked_flags = 0; + rt_mutex_init(&adap->bus_lock); + rt_mutex_init(&adap->mux_lock); + mutex_init(&adap->userspace_clients_lock); + INIT_LIST_HEAD(&adap->userspace_clients); + + /* Set default timeout to 1 second if not already set */ + if (adap->timeout == 0) + adap->timeout = HZ; + + /* register soft irqs for Host Notify */ + res = i2c_setup_host_notify_irq_domain(adap); + if (res) { + pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n", + adap->name, res); + goto out_list; + } + + dev_set_name(&adap->dev, "i2c-%d", adap->nr); + adap->dev.bus = &i2c_bus_type; + adap->dev.type = &i2c_adapter_type; + res = device_register(&adap->dev); + if (res) { + pr_err("adapter '%s': can't register device (%d)\n", adap->name, res); + goto out_list; + } + + res = i2c_setup_smbus_alert(adap); + if (res) + goto out_reg; + + device_enable_async_suspend(&adap->dev); + pm_runtime_no_callbacks(&adap->dev); + pm_suspend_ignore_children(&adap->dev, true); + pm_runtime_enable(&adap->dev); + + res = i2c_init_recovery(adap); + if (res == -EPROBE_DEFER) + goto out_reg; + + dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name); + +#ifdef CONFIG_I2C_COMPAT + res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev, + adap->dev.parent); + if (res) + dev_warn(&adap->dev, + "Failed to create compatibility class link\n"); +#endif + + /* create pre-declared device nodes */ + of_i2c_register_devices(adap); + i2c_acpi_install_space_handler(adap); + i2c_acpi_register_devices(adap); + + if (adap->nr < __i2c_first_dynamic_bus_num) + i2c_scan_static_board_info(adap); + + /* Notify drivers */ + mutex_lock(&core_lock); + bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); + mutex_unlock(&core_lock); + + return 0; + +out_reg: + init_completion(&adap->dev_released); + device_unregister(&adap->dev); + wait_for_completion(&adap->dev_released); +out_list: + mutex_lock(&core_lock); + idr_remove(&i2c_adapter_idr, adap->nr); + mutex_unlock(&core_lock); + return res; +} + +/** + * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1 + * @adap: the adapter to register (with adap->nr initialized) + * Context: can sleep + * + * See i2c_add_numbered_adapter() for details. + */ +static int __i2c_add_numbered_adapter(struct i2c_adapter *adap) +{ + int id; + + mutex_lock(&core_lock); + id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL); + mutex_unlock(&core_lock); + if (WARN(id < 0, "couldn't get idr")) + return id == -ENOSPC ? -EBUSY : id; + + return i2c_register_adapter(adap); +} + +/** + * i2c_add_adapter - declare i2c adapter, use dynamic bus number + * @adapter: the adapter to add + * Context: can sleep + * + * This routine is used to declare an I2C adapter when its bus number + * doesn't matter or when its bus number is specified by an dt alias. + * Examples of bases when the bus number doesn't matter: I2C adapters + * dynamically added by USB links or PCI plugin cards. + * + * When this returns zero, a new bus number was allocated and stored + * in adap->nr, and the specified adapter became available for clients. + * Otherwise, a negative errno value is returned. + */ +int i2c_add_adapter(struct i2c_adapter *adapter) +{ + struct device *dev = &adapter->dev; + int id; + + if (dev->of_node) { + id = of_alias_get_id(dev->of_node, "i2c"); + if (id >= 0) { + adapter->nr = id; + return __i2c_add_numbered_adapter(adapter); + } + } + + mutex_lock(&core_lock); + id = idr_alloc(&i2c_adapter_idr, adapter, + __i2c_first_dynamic_bus_num, 0, GFP_KERNEL); + mutex_unlock(&core_lock); + if (WARN(id < 0, "couldn't get idr")) + return id; + + adapter->nr = id; + + return i2c_register_adapter(adapter); +} +EXPORT_SYMBOL(i2c_add_adapter); + +/** + * i2c_add_numbered_adapter - declare i2c adapter, use static bus number + * @adap: the adapter to register (with adap->nr initialized) + * Context: can sleep + * + * This routine is used to declare an I2C adapter when its bus number + * matters. For example, use it for I2C adapters from system-on-chip CPUs, + * or otherwise built in to the system's mainboard, and where i2c_board_info + * is used to properly configure I2C devices. + * + * If the requested bus number is set to -1, then this function will behave + * identically to i2c_add_adapter, and will dynamically assign a bus number. + * + * If no devices have pre-been declared for this bus, then be sure to + * register the adapter before any dynamically allocated ones. Otherwise + * the required bus ID may not be available. + * + * When this returns zero, the specified adapter became available for + * clients using the bus number provided in adap->nr. Also, the table + * of I2C devices pre-declared using i2c_register_board_info() is scanned, + * and the appropriate driver model device nodes are created. Otherwise, a + * negative errno value is returned. + */ +int i2c_add_numbered_adapter(struct i2c_adapter *adap) +{ + if (adap->nr == -1) /* -1 means dynamically assign bus id */ + return i2c_add_adapter(adap); + + return __i2c_add_numbered_adapter(adap); +} +EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); + +static void i2c_do_del_adapter(struct i2c_driver *driver, + struct i2c_adapter *adapter) +{ + struct i2c_client *client, *_n; + + /* Remove the devices we created ourselves as the result of hardware + * probing (using a driver's detect method) */ + list_for_each_entry_safe(client, _n, &driver->clients, detected) { + if (client->adapter == adapter) { + dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", + client->name, client->addr); + list_del(&client->detected); + i2c_unregister_device(client); + } + } +} + +static int __unregister_client(struct device *dev, void *dummy) +{ + struct i2c_client *client = i2c_verify_client(dev); + if (client && strcmp(client->name, "dummy")) + i2c_unregister_device(client); + return 0; +} + +static int __unregister_dummy(struct device *dev, void *dummy) +{ + struct i2c_client *client = i2c_verify_client(dev); + i2c_unregister_device(client); + return 0; +} + +static int __process_removed_adapter(struct device_driver *d, void *data) +{ + i2c_do_del_adapter(to_i2c_driver(d), data); + return 0; +} + +/** + * i2c_del_adapter - unregister I2C adapter + * @adap: the adapter being unregistered + * Context: can sleep + * + * This unregisters an I2C adapter which was previously registered + * by @i2c_add_adapter or @i2c_add_numbered_adapter. + */ +void i2c_del_adapter(struct i2c_adapter *adap) +{ + struct i2c_adapter *found; + struct i2c_client *client, *next; + + /* First make sure that this adapter was ever added */ + mutex_lock(&core_lock); + found = idr_find(&i2c_adapter_idr, adap->nr); + mutex_unlock(&core_lock); + if (found != adap) { + pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name); + return; + } + + i2c_acpi_remove_space_handler(adap); + /* Tell drivers about this removal */ + mutex_lock(&core_lock); + bus_for_each_drv(&i2c_bus_type, NULL, adap, + __process_removed_adapter); + mutex_unlock(&core_lock); + + /* Remove devices instantiated from sysfs */ + mutex_lock_nested(&adap->userspace_clients_lock, + i2c_adapter_depth(adap)); + list_for_each_entry_safe(client, next, &adap->userspace_clients, + detected) { + dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name, + client->addr); + list_del(&client->detected); + i2c_unregister_device(client); + } + mutex_unlock(&adap->userspace_clients_lock); + + /* Detach any active clients. This can't fail, thus we do not + * check the returned value. This is a two-pass process, because + * we can't remove the dummy devices during the first pass: they + * could have been instantiated by real devices wishing to clean + * them up properly, so we give them a chance to do that first. */ + device_for_each_child(&adap->dev, NULL, __unregister_client); + device_for_each_child(&adap->dev, NULL, __unregister_dummy); + +#ifdef CONFIG_I2C_COMPAT + class_compat_remove_link(i2c_adapter_compat_class, &adap->dev, + adap->dev.parent); +#endif + + /* device name is gone after device_unregister */ + dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name); + + pm_runtime_disable(&adap->dev); + + i2c_host_notify_irq_teardown(adap); + + /* wait until all references to the device are gone + * + * FIXME: This is old code and should ideally be replaced by an + * alternative which results in decoupling the lifetime of the struct + * device from the i2c_adapter, like spi or netdev do. Any solution + * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled! + */ + init_completion(&adap->dev_released); + device_unregister(&adap->dev); + wait_for_completion(&adap->dev_released); + + /* free bus id */ + mutex_lock(&core_lock); + idr_remove(&i2c_adapter_idr, adap->nr); + mutex_unlock(&core_lock); + + /* Clear the device structure in case this adapter is ever going to be + added again */ + memset(&adap->dev, 0, sizeof(adap->dev)); +} +EXPORT_SYMBOL(i2c_del_adapter); + +static void devm_i2c_del_adapter(void *adapter) +{ + i2c_del_adapter(adapter); +} + +/** + * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter() + * @dev: managing device for adding this I2C adapter + * @adapter: the adapter to add + * Context: can sleep + * + * Add adapter with dynamic bus number, same with i2c_add_adapter() + * but the adapter will be auto deleted on driver detach. + */ +int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter) +{ + int ret; + + ret = i2c_add_adapter(adapter); + if (ret) + return ret; + + return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter); +} +EXPORT_SYMBOL_GPL(devm_i2c_add_adapter); + +static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p, + u32 def_val, bool use_def) +{ + int ret; + + ret = device_property_read_u32(dev, prop_name, cur_val_p); + if (ret && use_def) + *cur_val_p = def_val; + + dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p); +} + +/** + * i2c_parse_fw_timings - get I2C related timing parameters from firmware + * @dev: The device to scan for I2C timing properties + * @t: the i2c_timings struct to be filled with values + * @use_defaults: bool to use sane defaults derived from the I2C specification + * when properties are not found, otherwise don't update + * + * Scan the device for the generic I2C properties describing timing parameters + * for the signal and fill the given struct with the results. If a property was + * not found and use_defaults was true, then maximum timings are assumed which + * are derived from the I2C specification. If use_defaults is not used, the + * results will be as before, so drivers can apply their own defaults before + * calling this helper. The latter is mainly intended for avoiding regressions + * of existing drivers which want to switch to this function. New drivers + * almost always should use the defaults. + */ +void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults) +{ + bool u = use_defaults; + u32 d; + + i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz, + I2C_MAX_STANDARD_MODE_FREQ, u); + + d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 : + t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; + i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u); + + d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; + i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u); + + i2c_parse_timing(dev, "i2c-scl-internal-delay-ns", + &t->scl_int_delay_ns, 0, u); + i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns, + t->scl_fall_ns, u); + i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u); + i2c_parse_timing(dev, "i2c-digital-filter-width-ns", + &t->digital_filter_width_ns, 0, u); + i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency", + &t->analog_filter_cutoff_freq_hz, 0, u); +} +EXPORT_SYMBOL_GPL(i2c_parse_fw_timings); + +/* ------------------------------------------------------------------------- */ + +int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data)) +{ + int res; + + mutex_lock(&core_lock); + res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn); + mutex_unlock(&core_lock); + + return res; +} +EXPORT_SYMBOL_GPL(i2c_for_each_dev); + +static int __process_new_driver(struct device *dev, void *data) +{ + if (dev->type != &i2c_adapter_type) + return 0; + return i2c_do_add_adapter(data, to_i2c_adapter(dev)); +} + +/* + * An i2c_driver is used with one or more i2c_client (device) nodes to access + * i2c slave chips, on a bus instance associated with some i2c_adapter. + */ + +int i2c_register_driver(struct module *owner, struct i2c_driver *driver) +{ + int res; + + /* Can't register until after driver model init */ + if (WARN_ON(!is_registered)) + return -EAGAIN; + + /* add the driver to the list of i2c drivers in the driver core */ + driver->driver.owner = owner; + driver->driver.bus = &i2c_bus_type; + INIT_LIST_HEAD(&driver->clients); + + /* When registration returns, the driver core + * will have called probe() for all matching-but-unbound devices. + */ + res = driver_register(&driver->driver); + if (res) + return res; + + pr_debug("driver [%s] registered\n", driver->driver.name); + + /* Walk the adapters that are already present */ + i2c_for_each_dev(driver, __process_new_driver); + + return 0; +} +EXPORT_SYMBOL(i2c_register_driver); + +static int __process_removed_driver(struct device *dev, void *data) +{ + if (dev->type == &i2c_adapter_type) + i2c_do_del_adapter(data, to_i2c_adapter(dev)); + return 0; +} + +/** + * i2c_del_driver - unregister I2C driver + * @driver: the driver being unregistered + * Context: can sleep + */ +void i2c_del_driver(struct i2c_driver *driver) +{ + i2c_for_each_dev(driver, __process_removed_driver); + + driver_unregister(&driver->driver); + pr_debug("driver [%s] unregistered\n", driver->driver.name); +} +EXPORT_SYMBOL(i2c_del_driver); + +/* ------------------------------------------------------------------------- */ + +struct i2c_cmd_arg { + unsigned cmd; + void *arg; +}; + +static int i2c_cmd(struct device *dev, void *_arg) +{ + struct i2c_client *client = i2c_verify_client(dev); + struct i2c_cmd_arg *arg = _arg; + struct i2c_driver *driver; + + if (!client || !client->dev.driver) + return 0; + + driver = to_i2c_driver(client->dev.driver); + if (driver->command) + driver->command(client, arg->cmd, arg->arg); + return 0; +} + +void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg) +{ + struct i2c_cmd_arg cmd_arg; + + cmd_arg.cmd = cmd; + cmd_arg.arg = arg; + device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd); +} +EXPORT_SYMBOL(i2c_clients_command); + +static int __init i2c_init(void) +{ + int retval; + + retval = of_alias_get_highest_id("i2c"); + + down_write(&__i2c_board_lock); + if (retval >= __i2c_first_dynamic_bus_num) + __i2c_first_dynamic_bus_num = retval + 1; + up_write(&__i2c_board_lock); + + retval = bus_register(&i2c_bus_type); + if (retval) + return retval; + + is_registered = true; + +#ifdef CONFIG_I2C_COMPAT + i2c_adapter_compat_class = class_compat_register("i2c-adapter"); + if (!i2c_adapter_compat_class) { + retval = -ENOMEM; + goto bus_err; + } +#endif + retval = i2c_add_driver(&dummy_driver); + if (retval) + goto class_err; + + if (IS_ENABLED(CONFIG_OF_DYNAMIC)) + WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier)); + if (IS_ENABLED(CONFIG_ACPI)) + WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier)); + + return 0; + +class_err: +#ifdef CONFIG_I2C_COMPAT + class_compat_unregister(i2c_adapter_compat_class); +bus_err: +#endif + is_registered = false; + bus_unregister(&i2c_bus_type); + return retval; +} + +static void __exit i2c_exit(void) +{ + if (IS_ENABLED(CONFIG_ACPI)) + WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier)); + if (IS_ENABLED(CONFIG_OF_DYNAMIC)) + WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier)); + i2c_del_driver(&dummy_driver); +#ifdef CONFIG_I2C_COMPAT + class_compat_unregister(i2c_adapter_compat_class); +#endif + bus_unregister(&i2c_bus_type); + tracepoint_synchronize_unregister(); +} + +/* We must initialize early, because some subsystems register i2c drivers + * in subsys_initcall() code, but are linked (and initialized) before i2c. + */ +postcore_initcall(i2c_init); +module_exit(i2c_exit); + +/* ---------------------------------------------------- + * the functional interface to the i2c busses. + * ---------------------------------------------------- + */ + +/* Check if val is exceeding the quirk IFF quirk is non 0 */ +#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) + +static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) +{ + dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n", + err_msg, msg->addr, msg->len, + msg->flags & I2C_M_RD ? "read" : "write"); + return -EOPNOTSUPP; +} + +static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + const struct i2c_adapter_quirks *q = adap->quirks; + int max_num = q->max_num_msgs, i; + bool do_len_check = true; + + if (q->flags & I2C_AQ_COMB) { + max_num = 2; + + /* special checks for combined messages */ + if (num == 2) { + if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD) + return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write"); + + if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD)) + return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read"); + + if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr) + return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr"); + + if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len)) + return i2c_quirk_error(adap, &msgs[0], "msg too long"); + + if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len)) + return i2c_quirk_error(adap, &msgs[1], "msg too long"); + + do_len_check = false; + } + } + + if (i2c_quirk_exceeded(num, max_num)) + return i2c_quirk_error(adap, &msgs[0], "too many messages"); + + for (i = 0; i < num; i++) { + u16 len = msgs[i].len; + + if (msgs[i].flags & I2C_M_RD) { + if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len)) + return i2c_quirk_error(adap, &msgs[i], "msg too long"); + + if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0) + return i2c_quirk_error(adap, &msgs[i], "no zero length"); + } else { + if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len)) + return i2c_quirk_error(adap, &msgs[i], "msg too long"); + + if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0) + return i2c_quirk_error(adap, &msgs[i], "no zero length"); + } + } + + return 0; +} + +/** + * __i2c_transfer - unlocked flavor of i2c_transfer + * @adap: Handle to I2C bus + * @msgs: One or more messages to execute before STOP is issued to + * terminate the operation; each message begins with a START. + * @num: Number of messages to be executed. + * + * Returns negative errno, else the number of messages executed. + * + * Adapter lock must be held when calling this function. No debug logging + * takes place. adap->algo->master_xfer existence isn't checked. + */ +int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + unsigned long orig_jiffies; + int ret, try; + + if (WARN_ON(!msgs || num < 1)) + return -EINVAL; + + ret = __i2c_check_suspended(adap); + if (ret) + return ret; + + if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) + return -EOPNOTSUPP; + + /* + * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets + * enabled. This is an efficient way of keeping the for-loop from + * being executed when not needed. + */ + if (static_branch_unlikely(&i2c_trace_msg_key)) { + int i; + for (i = 0; i < num; i++) + if (msgs[i].flags & I2C_M_RD) + trace_i2c_read(adap, &msgs[i], i); + else + trace_i2c_write(adap, &msgs[i], i); + } + + /* Retry automatically on arbitration loss */ + orig_jiffies = jiffies; + for (ret = 0, try = 0; try <= adap->retries; try++) { + if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic) + ret = adap->algo->master_xfer_atomic(adap, msgs, num); + else + ret = adap->algo->master_xfer(adap, msgs, num); + + if (ret != -EAGAIN) + break; + if (time_after(jiffies, orig_jiffies + adap->timeout)) + break; + } + + if (static_branch_unlikely(&i2c_trace_msg_key)) { + int i; + for (i = 0; i < ret; i++) + if (msgs[i].flags & I2C_M_RD) + trace_i2c_reply(adap, &msgs[i], i); + trace_i2c_result(adap, num, ret); + } + + return ret; +} +EXPORT_SYMBOL(__i2c_transfer); + +/** + * i2c_transfer - execute a single or combined I2C message + * @adap: Handle to I2C bus + * @msgs: One or more messages to execute before STOP is issued to + * terminate the operation; each message begins with a START. + * @num: Number of messages to be executed. + * + * Returns negative errno, else the number of messages executed. + * + * Note that there is no requirement that each message be sent to + * the same slave address, although that is the most common model. + */ +int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + int ret; + + if (!adap->algo->master_xfer) { + dev_dbg(&adap->dev, "I2C level transfers not supported\n"); + return -EOPNOTSUPP; + } + + /* REVISIT the fault reporting model here is weak: + * + * - When we get an error after receiving N bytes from a slave, + * there is no way to report "N". + * + * - When we get a NAK after transmitting N bytes to a slave, + * there is no way to report "N" ... or to let the master + * continue executing the rest of this combined message, if + * that's the appropriate response. + * + * - When for example "num" is two and we successfully complete + * the first message but get an error part way through the + * second, it's unclear whether that should be reported as + * one (discarding status on the second message) or errno + * (discarding status on the first one). + */ + ret = __i2c_lock_bus_helper(adap); + if (ret) + return ret; + + ret = __i2c_transfer(adap, msgs, num); + i2c_unlock_bus(adap, I2C_LOCK_SEGMENT); + + return ret; +} +EXPORT_SYMBOL(i2c_transfer); + +/** + * i2c_transfer_buffer_flags - issue a single I2C message transferring data + * to/from a buffer + * @client: Handle to slave device + * @buf: Where the data is stored + * @count: How many bytes to transfer, must be less than 64k since msg.len is u16 + * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads + * + * Returns negative errno, or else the number of bytes transferred. + */ +int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf, + int count, u16 flags) +{ + int ret; + struct i2c_msg msg = { + .addr = client->addr, + .flags = flags | (client->flags & I2C_M_TEN), + .len = count, + .buf = buf, + }; + + ret = i2c_transfer(client->adapter, &msg, 1); + + /* + * If everything went ok (i.e. 1 msg transferred), return #bytes + * transferred, else error code. + */ + return (ret == 1) ? count : ret; +} +EXPORT_SYMBOL(i2c_transfer_buffer_flags); + +/** + * i2c_get_device_id - get manufacturer, part id and die revision of a device + * @client: The device to query + * @id: The queried information + * + * Returns negative errno on error, zero on success. + */ +int i2c_get_device_id(const struct i2c_client *client, + struct i2c_device_identity *id) +{ + struct i2c_adapter *adap = client->adapter; + union i2c_smbus_data raw_id; + int ret; + + if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) + return -EOPNOTSUPP; + + raw_id.block[0] = 3; + ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0, + I2C_SMBUS_READ, client->addr << 1, + I2C_SMBUS_I2C_BLOCK_DATA, &raw_id); + if (ret) + return ret; + + id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4); + id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3); + id->die_revision = raw_id.block[3] & 0x7; + return 0; +} +EXPORT_SYMBOL_GPL(i2c_get_device_id); + +/* ---------------------------------------------------- + * the i2c address scanning function + * Will not work for 10-bit addresses! + * ---------------------------------------------------- + */ + +/* + * Legacy default probe function, mostly relevant for SMBus. The default + * probe method is a quick write, but it is known to corrupt the 24RF08 + * EEPROMs due to a state machine bug, and could also irreversibly + * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f, + * we use a short byte read instead. Also, some bus drivers don't implement + * quick write, so we fallback to a byte read in that case too. + * On x86, there is another special case for FSC hardware monitoring chips, + * which want regular byte reads (address 0x73.) Fortunately, these are the + * only known chips using this I2C address on PC hardware. + * Returns 1 if probe succeeded, 0 if not. + */ +static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr) +{ + int err; + union i2c_smbus_data dummy; + +#ifdef CONFIG_X86 + if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON) + && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA)) + err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, + I2C_SMBUS_BYTE_DATA, &dummy); + else +#endif + if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50) + && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) + err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0, + I2C_SMBUS_QUICK, NULL); + else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) + err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, + I2C_SMBUS_BYTE, &dummy); + else { + dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n", + addr); + err = -EOPNOTSUPP; + } + + return err >= 0; +} + +static int i2c_detect_address(struct i2c_client *temp_client, + struct i2c_driver *driver) +{ + struct i2c_board_info info; + struct i2c_adapter *adapter = temp_client->adapter; + int addr = temp_client->addr; + int err; + + /* Make sure the address is valid */ + err = i2c_check_7bit_addr_validity_strict(addr); + if (err) { + dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n", + addr); + return err; + } + + /* Skip if already in use (7 bit, no need to encode flags) */ + if (i2c_check_addr_busy(adapter, addr)) + return 0; + + /* Make sure there is something at this address */ + if (!i2c_default_probe(adapter, addr)) + return 0; + + /* Finally call the custom detection function */ + memset(&info, 0, sizeof(struct i2c_board_info)); + info.addr = addr; + err = driver->detect(temp_client, &info); + if (err) { + /* -ENODEV is returned if the detection fails. We catch it + here as this isn't an error. */ + return err == -ENODEV ? 0 : err; + } + + /* Consistency check */ + if (info.type[0] == '\0') { + dev_err(&adapter->dev, + "%s detection function provided no name for 0x%x\n", + driver->driver.name, addr); + } else { + struct i2c_client *client; + + /* Detection succeeded, instantiate the device */ + if (adapter->class & I2C_CLASS_DEPRECATED) + dev_warn(&adapter->dev, + "This adapter will soon drop class based instantiation of devices. " + "Please make sure client 0x%02x gets instantiated by other means. " + "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n", + info.addr); + + dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n", + info.type, info.addr); + client = i2c_new_client_device(adapter, &info); + if (!IS_ERR(client)) + list_add_tail(&client->detected, &driver->clients); + else + dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n", + info.type, info.addr); + } + return 0; +} + +static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) +{ + const unsigned short *address_list; + struct i2c_client *temp_client; + int i, err = 0; + + address_list = driver->address_list; + if (!driver->detect || !address_list) + return 0; + + /* Warn that the adapter lost class based instantiation */ + if (adapter->class == I2C_CLASS_DEPRECATED) { + dev_dbg(&adapter->dev, + "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. " + "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n", + driver->driver.name); + return 0; + } + + /* Stop here if the classes do not match */ + if (!(adapter->class & driver->class)) + return 0; + + /* Set up a temporary client to help detect callback */ + temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL); + if (!temp_client) + return -ENOMEM; + temp_client->adapter = adapter; + + for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) { + dev_dbg(&adapter->dev, + "found normal entry for adapter %d, addr 0x%02x\n", + i2c_adapter_id(adapter), address_list[i]); + temp_client->addr = address_list[i]; + err = i2c_detect_address(temp_client, driver); + if (unlikely(err)) + break; + } + + kfree(temp_client); + return err; +} + +int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr) +{ + return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, + I2C_SMBUS_QUICK, NULL) >= 0; +} +EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read); + +struct i2c_client * +i2c_new_scanned_device(struct i2c_adapter *adap, + struct i2c_board_info *info, + unsigned short const *addr_list, + int (*probe)(struct i2c_adapter *adap, unsigned short addr)) +{ + int i; + + if (!probe) + probe = i2c_default_probe; + + for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) { + /* Check address validity */ + if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) { + dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n", + addr_list[i]); + continue; + } + + /* Check address availability (7 bit, no need to encode flags) */ + if (i2c_check_addr_busy(adap, addr_list[i])) { + dev_dbg(&adap->dev, + "Address 0x%02x already in use, not probing\n", + addr_list[i]); + continue; + } + + /* Test address responsiveness */ + if (probe(adap, addr_list[i])) + break; + } + + if (addr_list[i] == I2C_CLIENT_END) { + dev_dbg(&adap->dev, "Probing failed, no device found\n"); + return ERR_PTR(-ENODEV); + } + + info->addr = addr_list[i]; + return i2c_new_client_device(adap, info); +} +EXPORT_SYMBOL_GPL(i2c_new_scanned_device); + +struct i2c_adapter *i2c_get_adapter(int nr) +{ + struct i2c_adapter *adapter; + + mutex_lock(&core_lock); + adapter = idr_find(&i2c_adapter_idr, nr); + if (!adapter) + goto exit; + + if (try_module_get(adapter->owner)) + get_device(&adapter->dev); + else + adapter = NULL; + + exit: + mutex_unlock(&core_lock); + return adapter; +} +EXPORT_SYMBOL(i2c_get_adapter); + +void i2c_put_adapter(struct i2c_adapter *adap) +{ + if (!adap) + return; + + module_put(adap->owner); + /* Should be last, otherwise we risk use-after-free with 'adap' */ + put_device(&adap->dev); +} +EXPORT_SYMBOL(i2c_put_adapter); + +/** + * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg + * @msg: the message to be checked + * @threshold: the minimum number of bytes for which using DMA makes sense. + * Should at least be 1. + * + * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO. + * Or a valid pointer to be used with DMA. After use, release it by + * calling i2c_put_dma_safe_msg_buf(). + * + * This function must only be called from process context! + */ +u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold) +{ + /* also skip 0-length msgs for bogus thresholds of 0 */ + if (!threshold) + pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n", + msg->addr); + if (msg->len < threshold || msg->len == 0) + return NULL; + + if (msg->flags & I2C_M_DMA_SAFE) + return msg->buf; + + pr_debug("using bounce buffer for addr=0x%02x, len=%d\n", + msg->addr, msg->len); + + if (msg->flags & I2C_M_RD) + return kzalloc(msg->len, GFP_KERNEL); + else + return kmemdup(msg->buf, msg->len, GFP_KERNEL); +} +EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf); + +/** + * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg + * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL. + * @msg: the message which the buffer corresponds to + * @xferred: bool saying if the message was transferred + */ +void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred) +{ + if (!buf || buf == msg->buf) + return; + + if (xferred && msg->flags & I2C_M_RD) + memcpy(msg->buf, buf, msg->len); + + kfree(buf); +} +EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf); + +MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); +MODULE_DESCRIPTION("I2C-Bus main module"); +MODULE_LICENSE("GPL"); |