diff options
Diffstat (limited to 'drivers/i2c/i2c-core-acpi.c')
| -rw-r--r-- | drivers/i2c/i2c-core-acpi.c | 760 |
1 files changed, 760 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c new file mode 100644 index 000000000..4b136d871 --- /dev/null +++ b/drivers/i2c/i2c-core-acpi.c @@ -0,0 +1,760 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Linux I2C core ACPI support code + * + * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com> + */ + +#include <linux/acpi.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/slab.h> + +#include "i2c-core.h" + +struct i2c_acpi_handler_data { + struct acpi_connection_info info; + struct i2c_adapter *adapter; +}; + +struct gsb_buffer { + u8 status; + u8 len; + union { + u16 wdata; + u8 bdata; + u8 data[0]; + }; +} __packed; + +struct i2c_acpi_lookup { + struct i2c_board_info *info; + acpi_handle adapter_handle; + acpi_handle device_handle; + acpi_handle search_handle; + int n; + int index; + u32 speed; + u32 min_speed; + u32 force_speed; +}; + +/** + * i2c_acpi_get_i2c_resource - Gets I2cSerialBus resource if type matches + * @ares: ACPI resource + * @i2c: Pointer to I2cSerialBus resource will be returned here + * + * Checks if the given ACPI resource is of type I2cSerialBus. + * In this case, returns a pointer to it to the caller. + * + * Returns true if resource type is of I2cSerialBus, otherwise false. + */ +bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares, + struct acpi_resource_i2c_serialbus **i2c) +{ + struct acpi_resource_i2c_serialbus *sb; + + if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) + return false; + + sb = &ares->data.i2c_serial_bus; + if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) + return false; + + *i2c = sb; + return true; +} +EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource); + +static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data) +{ + struct i2c_acpi_lookup *lookup = data; + struct i2c_board_info *info = lookup->info; + struct acpi_resource_i2c_serialbus *sb; + acpi_status status; + + if (info->addr || !i2c_acpi_get_i2c_resource(ares, &sb)) + return 1; + + if (lookup->index != -1 && lookup->n++ != lookup->index) + return 1; + + status = acpi_get_handle(lookup->device_handle, + sb->resource_source.string_ptr, + &lookup->adapter_handle); + if (ACPI_FAILURE(status)) + return 1; + + info->addr = sb->slave_address; + lookup->speed = sb->connection_speed; + if (sb->access_mode == ACPI_I2C_10BIT_MODE) + info->flags |= I2C_CLIENT_TEN; + + return 1; +} + +static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = { + /* + * ACPI video acpi_devices, which are handled by the acpi-video driver + * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these. + */ + { ACPI_VIDEO_HID, 0 }, + {} +}; + +static int i2c_acpi_do_lookup(struct acpi_device *adev, + struct i2c_acpi_lookup *lookup) +{ + struct i2c_board_info *info = lookup->info; + struct list_head resource_list; + int ret; + + if (acpi_bus_get_status(adev) || !adev->status.present) + return -EINVAL; + + if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0) + return -ENODEV; + + memset(info, 0, sizeof(*info)); + lookup->device_handle = acpi_device_handle(adev); + + /* Look up for I2cSerialBus resource */ + INIT_LIST_HEAD(&resource_list); + ret = acpi_dev_get_resources(adev, &resource_list, + i2c_acpi_fill_info, lookup); + acpi_dev_free_resource_list(&resource_list); + + if (ret < 0 || !info->addr) + return -EINVAL; + + return 0; +} + +static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data) +{ + int *irq = data; + struct resource r; + + if (*irq <= 0 && acpi_dev_resource_interrupt(ares, 0, &r)) + *irq = i2c_dev_irq_from_resources(&r, 1); + + return 1; /* No need to add resource to the list */ +} + +/** + * i2c_acpi_get_irq - get device IRQ number from ACPI + * @client: Pointer to the I2C client device + * + * Find the IRQ number used by a specific client device. + * + * Return: The IRQ number or an error code. + */ +int i2c_acpi_get_irq(struct i2c_client *client) +{ + struct acpi_device *adev = ACPI_COMPANION(&client->dev); + struct list_head resource_list; + int irq = -ENOENT; + int ret; + + INIT_LIST_HEAD(&resource_list); + + ret = acpi_dev_get_resources(adev, &resource_list, + i2c_acpi_add_resource, &irq); + if (ret < 0) + return ret; + + acpi_dev_free_resource_list(&resource_list); + + if (irq == -ENOENT) + irq = acpi_dev_gpio_irq_get(adev, 0); + + return irq; +} + +static int i2c_acpi_get_info(struct acpi_device *adev, + struct i2c_board_info *info, + struct i2c_adapter *adapter, + acpi_handle *adapter_handle) +{ + struct i2c_acpi_lookup lookup; + int ret; + + memset(&lookup, 0, sizeof(lookup)); + lookup.info = info; + lookup.index = -1; + + if (acpi_device_enumerated(adev)) + return -EINVAL; + + ret = i2c_acpi_do_lookup(adev, &lookup); + if (ret) + return ret; + + if (adapter) { + /* The adapter must match the one in I2cSerialBus() connector */ + if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle) + return -ENODEV; + } else { + struct acpi_device *adapter_adev; + + /* The adapter must be present */ + if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev)) + return -ENODEV; + if (acpi_bus_get_status(adapter_adev) || + !adapter_adev->status.present) + return -ENODEV; + } + + info->fwnode = acpi_fwnode_handle(adev); + if (adapter_handle) + *adapter_handle = lookup.adapter_handle; + + acpi_set_modalias(adev, dev_name(&adev->dev), info->type, + sizeof(info->type)); + + return 0; +} + +static void i2c_acpi_register_device(struct i2c_adapter *adapter, + struct acpi_device *adev, + struct i2c_board_info *info) +{ + adev->power.flags.ignore_parent = true; + acpi_device_set_enumerated(adev); + + if (IS_ERR(i2c_new_client_device(adapter, info))) { + adev->power.flags.ignore_parent = false; + dev_err(&adapter->dev, + "failed to add I2C device %s from ACPI\n", + dev_name(&adev->dev)); + } +} + +static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level, + void *data, void **return_value) +{ + struct i2c_adapter *adapter = data; + struct acpi_device *adev; + struct i2c_board_info info; + + if (acpi_bus_get_device(handle, &adev)) + return AE_OK; + + if (i2c_acpi_get_info(adev, &info, adapter, NULL)) + return AE_OK; + + i2c_acpi_register_device(adapter, adev, &info); + + return AE_OK; +} + +#define I2C_ACPI_MAX_SCAN_DEPTH 32 + +/** + * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter + * @adap: pointer to adapter + * + * Enumerate all I2C slave devices behind this adapter by walking the ACPI + * namespace. When a device is found it will be added to the Linux device + * model and bound to the corresponding ACPI handle. + */ +void i2c_acpi_register_devices(struct i2c_adapter *adap) +{ + acpi_status status; + acpi_handle handle; + + if (!has_acpi_companion(&adap->dev)) + return; + + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, + I2C_ACPI_MAX_SCAN_DEPTH, + i2c_acpi_add_device, NULL, + adap, NULL); + if (ACPI_FAILURE(status)) + dev_warn(&adap->dev, "failed to enumerate I2C slaves\n"); + + if (!adap->dev.parent) + return; + + handle = ACPI_HANDLE(adap->dev.parent); + if (!handle) + return; + + acpi_walk_dep_device_list(handle); +} + +static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = { + /* + * These Silead touchscreen controllers only work at 400KHz, for + * some reason they do not work at 100KHz. On some devices the ACPI + * tables list another device at their bus as only being capable + * of 100KHz, testing has shown that these other devices work fine + * at 400KHz (as can be expected of any recent i2c hw) so we force + * the speed of the bus to 400 KHz if a Silead device is present. + */ + { "MSSL1680", 0 }, + {} +}; + +static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level, + void *data, void **return_value) +{ + struct i2c_acpi_lookup *lookup = data; + struct acpi_device *adev; + + if (acpi_bus_get_device(handle, &adev)) + return AE_OK; + + if (i2c_acpi_do_lookup(adev, lookup)) + return AE_OK; + + if (lookup->search_handle != lookup->adapter_handle) + return AE_OK; + + if (lookup->speed <= lookup->min_speed) + lookup->min_speed = lookup->speed; + + if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0) + lookup->force_speed = I2C_MAX_FAST_MODE_FREQ; + + return AE_OK; +} + +/** + * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI + * @dev: The device owning the bus + * + * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves + * devices connected to this bus and use the speed of slowest device. + * + * Returns the speed in Hz or zero + */ +u32 i2c_acpi_find_bus_speed(struct device *dev) +{ + struct i2c_acpi_lookup lookup; + struct i2c_board_info dummy; + acpi_status status; + + if (!has_acpi_companion(dev)) + return 0; + + memset(&lookup, 0, sizeof(lookup)); + lookup.search_handle = ACPI_HANDLE(dev); + lookup.min_speed = UINT_MAX; + lookup.info = &dummy; + lookup.index = -1; + + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, + I2C_ACPI_MAX_SCAN_DEPTH, + i2c_acpi_lookup_speed, NULL, + &lookup, NULL); + + if (ACPI_FAILURE(status)) { + dev_warn(dev, "unable to find I2C bus speed from ACPI\n"); + return 0; + } + + if (lookup.force_speed) { + if (lookup.force_speed != lookup.min_speed) + dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n", + lookup.min_speed, lookup.force_speed); + return lookup.force_speed; + } else if (lookup.min_speed != UINT_MAX) { + return lookup.min_speed; + } else { + return 0; + } +} +EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed); + +static int i2c_acpi_find_match_adapter(struct device *dev, const void *data) +{ + struct i2c_adapter *adapter = i2c_verify_adapter(dev); + + if (!adapter) + return 0; + + return ACPI_HANDLE(dev) == (acpi_handle)data; +} + +struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle) +{ + struct device *dev; + + dev = bus_find_device(&i2c_bus_type, NULL, handle, + i2c_acpi_find_match_adapter); + + return dev ? i2c_verify_adapter(dev) : NULL; +} +EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle); + +static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev) +{ + struct device *dev; + struct i2c_client *client; + + dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev); + if (!dev) + return NULL; + + client = i2c_verify_client(dev); + if (!client) + put_device(dev); + + return client; +} + +static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value, + void *arg) +{ + struct acpi_device *adev = arg; + struct i2c_board_info info; + acpi_handle adapter_handle; + struct i2c_adapter *adapter; + struct i2c_client *client; + + switch (value) { + case ACPI_RECONFIG_DEVICE_ADD: + if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle)) + break; + + adapter = i2c_acpi_find_adapter_by_handle(adapter_handle); + if (!adapter) + break; + + i2c_acpi_register_device(adapter, adev, &info); + put_device(&adapter->dev); + break; + case ACPI_RECONFIG_DEVICE_REMOVE: + if (!acpi_device_enumerated(adev)) + break; + + client = i2c_acpi_find_client_by_adev(adev); + if (!client) + break; + + i2c_unregister_device(client); + put_device(&client->dev); + break; + } + + return NOTIFY_OK; +} + +struct notifier_block i2c_acpi_notifier = { + .notifier_call = i2c_acpi_notify, +}; + +/** + * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource + * @dev: Device owning the ACPI resources to get the client from + * @index: Index of ACPI resource to get + * @info: describes the I2C device; note this is modified (addr gets set) + * Context: can sleep + * + * By default the i2c subsys creates an i2c-client for the first I2cSerialBus + * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus + * resources, in that case this function can be used to create an i2c-client + * for other I2cSerialBus resources in the Current Resource Settings table. + * + * Also see i2c_new_client_device, which this function calls to create the + * i2c-client. + * + * Returns a pointer to the new i2c-client, or error pointer in case of failure. + * Specifically, -EPROBE_DEFER is returned if the adapter is not found. + */ +struct i2c_client *i2c_acpi_new_device(struct device *dev, int index, + struct i2c_board_info *info) +{ + struct acpi_device *adev = ACPI_COMPANION(dev); + struct i2c_acpi_lookup lookup; + struct i2c_adapter *adapter; + LIST_HEAD(resource_list); + int ret; + + memset(&lookup, 0, sizeof(lookup)); + lookup.info = info; + lookup.device_handle = acpi_device_handle(adev); + lookup.index = index; + + ret = acpi_dev_get_resources(adev, &resource_list, + i2c_acpi_fill_info, &lookup); + if (ret < 0) + return ERR_PTR(ret); + + acpi_dev_free_resource_list(&resource_list); + + if (!info->addr) + return ERR_PTR(-EADDRNOTAVAIL); + + adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle); + if (!adapter) + return ERR_PTR(-EPROBE_DEFER); + + return i2c_new_client_device(adapter, info); +} +EXPORT_SYMBOL_GPL(i2c_acpi_new_device); + +#ifdef CONFIG_ACPI_I2C_OPREGION +static int acpi_gsb_i2c_read_bytes(struct i2c_client *client, + u8 cmd, u8 *data, u8 data_len) +{ + + struct i2c_msg msgs[2]; + int ret; + u8 *buffer; + + buffer = kzalloc(data_len, GFP_KERNEL); + if (!buffer) + return AE_NO_MEMORY; + + msgs[0].addr = client->addr; + msgs[0].flags = client->flags; + msgs[0].len = 1; + msgs[0].buf = &cmd; + + msgs[1].addr = client->addr; + msgs[1].flags = client->flags | I2C_M_RD; + msgs[1].len = data_len; + msgs[1].buf = buffer; + + ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); + if (ret < 0) { + /* Getting a NACK is unfortunately normal with some DSTDs */ + if (ret == -EREMOTEIO) + dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n", + data_len, client->addr, cmd, ret); + else + dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n", + data_len, client->addr, cmd, ret); + /* 2 transfers must have completed successfully */ + } else if (ret == 2) { + memcpy(data, buffer, data_len); + ret = 0; + } else { + ret = -EIO; + } + + kfree(buffer); + return ret; +} + +static int acpi_gsb_i2c_write_bytes(struct i2c_client *client, + u8 cmd, u8 *data, u8 data_len) +{ + + struct i2c_msg msgs[1]; + u8 *buffer; + int ret = AE_OK; + + buffer = kzalloc(data_len + 1, GFP_KERNEL); + if (!buffer) + return AE_NO_MEMORY; + + buffer[0] = cmd; + memcpy(buffer + 1, data, data_len); + + msgs[0].addr = client->addr; + msgs[0].flags = client->flags; + msgs[0].len = data_len + 1; + msgs[0].buf = buffer; + + ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); + + kfree(buffer); + + if (ret < 0) { + dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret); + return ret; + } + + /* 1 transfer must have completed successfully */ + return (ret == 1) ? 0 : -EIO; +} + +static acpi_status +i2c_acpi_space_handler(u32 function, acpi_physical_address command, + u32 bits, u64 *value64, + void *handler_context, void *region_context) +{ + struct gsb_buffer *gsb = (struct gsb_buffer *)value64; + struct i2c_acpi_handler_data *data = handler_context; + struct acpi_connection_info *info = &data->info; + struct acpi_resource_i2c_serialbus *sb; + struct i2c_adapter *adapter = data->adapter; + struct i2c_client *client; + struct acpi_resource *ares; + u32 accessor_type = function >> 16; + u8 action = function & ACPI_IO_MASK; + acpi_status ret; + int status; + + ret = acpi_buffer_to_resource(info->connection, info->length, &ares); + if (ACPI_FAILURE(ret)) + return ret; + + client = kzalloc(sizeof(*client), GFP_KERNEL); + if (!client) { + ret = AE_NO_MEMORY; + goto err; + } + + if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) { + ret = AE_BAD_PARAMETER; + goto err; + } + + client->adapter = adapter; + client->addr = sb->slave_address; + + if (sb->access_mode == ACPI_I2C_10BIT_MODE) + client->flags |= I2C_CLIENT_TEN; + + switch (accessor_type) { + case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV: + if (action == ACPI_READ) { + status = i2c_smbus_read_byte(client); + if (status >= 0) { + gsb->bdata = status; + status = 0; + } + } else { + status = i2c_smbus_write_byte(client, gsb->bdata); + } + break; + + case ACPI_GSB_ACCESS_ATTRIB_BYTE: + if (action == ACPI_READ) { + status = i2c_smbus_read_byte_data(client, command); + if (status >= 0) { + gsb->bdata = status; + status = 0; + } + } else { + status = i2c_smbus_write_byte_data(client, command, + gsb->bdata); + } + break; + + case ACPI_GSB_ACCESS_ATTRIB_WORD: + if (action == ACPI_READ) { + status = i2c_smbus_read_word_data(client, command); + if (status >= 0) { + gsb->wdata = status; + status = 0; + } + } else { + status = i2c_smbus_write_word_data(client, command, + gsb->wdata); + } + break; + + case ACPI_GSB_ACCESS_ATTRIB_BLOCK: + if (action == ACPI_READ) { + status = i2c_smbus_read_block_data(client, command, + gsb->data); + if (status >= 0) { + gsb->len = status; + status = 0; + } + } else { + status = i2c_smbus_write_block_data(client, command, + gsb->len, gsb->data); + } + break; + + case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE: + if (action == ACPI_READ) { + status = acpi_gsb_i2c_read_bytes(client, command, + gsb->data, info->access_length); + } else { + status = acpi_gsb_i2c_write_bytes(client, command, + gsb->data, info->access_length); + } + break; + + default: + dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n", + accessor_type, client->addr); + ret = AE_BAD_PARAMETER; + goto err; + } + + gsb->status = status; + + err: + kfree(client); + ACPI_FREE(ares); + return ret; +} + + +int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) +{ + acpi_handle handle; + struct i2c_acpi_handler_data *data; + acpi_status status; + + if (!adapter->dev.parent) + return -ENODEV; + + handle = ACPI_HANDLE(adapter->dev.parent); + + if (!handle) + return -ENODEV; + + data = kzalloc(sizeof(struct i2c_acpi_handler_data), + GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->adapter = adapter; + status = acpi_bus_attach_private_data(handle, (void *)data); + if (ACPI_FAILURE(status)) { + kfree(data); + return -ENOMEM; + } + + status = acpi_install_address_space_handler(handle, + ACPI_ADR_SPACE_GSBUS, + &i2c_acpi_space_handler, + NULL, + data); + if (ACPI_FAILURE(status)) { + dev_err(&adapter->dev, "Error installing i2c space handler\n"); + acpi_bus_detach_private_data(handle); + kfree(data); + return -ENOMEM; + } + + return 0; +} + +void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) +{ + acpi_handle handle; + struct i2c_acpi_handler_data *data; + acpi_status status; + + if (!adapter->dev.parent) + return; + + handle = ACPI_HANDLE(adapter->dev.parent); + + if (!handle) + return; + + acpi_remove_address_space_handler(handle, + ACPI_ADR_SPACE_GSBUS, + &i2c_acpi_space_handler); + + status = acpi_bus_get_private_data(handle, (void **)&data); + if (ACPI_SUCCESS(status)) + kfree(data); + + acpi_bus_detach_private_data(handle); +} +#endif /* CONFIG_ACPI_I2C_OPREGION */ |