diff options
Diffstat (limited to 'drivers/platform/x86/siemens/simatic-ipc-batt.c')
| -rw-r--r-- | drivers/platform/x86/siemens/simatic-ipc-batt.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/drivers/platform/x86/siemens/simatic-ipc-batt.c b/drivers/platform/x86/siemens/simatic-ipc-batt.c new file mode 100644 index 0000000000..ef28c806b3 --- /dev/null +++ b/drivers/platform/x86/siemens/simatic-ipc-batt.c @@ -0,0 +1,253 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Siemens SIMATIC IPC driver for CMOS battery monitoring + * + * Copyright (c) Siemens AG, 2023 + * + * Authors: + * Gerd Haeussler <gerd.haeussler.ext@siemens.com> + * Henning Schild <henning.schild@siemens.com> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/ioport.h> +#include <linux/gpio/machine.h> +#include <linux/gpio/consumer.h> +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/platform_data/x86/simatic-ipc-base.h> +#include <linux/sizes.h> + +#include "simatic-ipc-batt.h" + +#define BATT_DELAY_MS (1000 * 60 * 60 * 24) /* 24 h delay */ + +#define SIMATIC_IPC_BATT_LEVEL_FULL 3000 +#define SIMATIC_IPC_BATT_LEVEL_CRIT 2750 +#define SIMATIC_IPC_BATT_LEVEL_EMPTY 0 + +static struct simatic_ipc_batt { + u8 devmode; + long current_state; + struct gpio_desc *gpios[3]; + unsigned long last_updated_jiffies; +} priv; + +static long simatic_ipc_batt_read_gpio(void) +{ + long r = SIMATIC_IPC_BATT_LEVEL_FULL; + + if (priv.gpios[2]) { + gpiod_set_value(priv.gpios[2], 1); + msleep(150); + } + + if (gpiod_get_value_cansleep(priv.gpios[0])) + r = SIMATIC_IPC_BATT_LEVEL_EMPTY; + else if (gpiod_get_value_cansleep(priv.gpios[1])) + r = SIMATIC_IPC_BATT_LEVEL_CRIT; + + if (priv.gpios[2]) + gpiod_set_value(priv.gpios[2], 0); + + return r; +} + +#define SIMATIC_IPC_BATT_PORT_BASE 0x404D +static struct resource simatic_ipc_batt_io_res = + DEFINE_RES_IO_NAMED(SIMATIC_IPC_BATT_PORT_BASE, SZ_1, KBUILD_MODNAME); + +static long simatic_ipc_batt_read_io(struct device *dev) +{ + long r = SIMATIC_IPC_BATT_LEVEL_FULL; + struct resource *res = &simatic_ipc_batt_io_res; + u8 val; + + if (!request_muxed_region(res->start, resource_size(res), res->name)) { + dev_err(dev, "Unable to register IO resource at %pR\n", res); + return -EBUSY; + } + + val = inb(SIMATIC_IPC_BATT_PORT_BASE); + release_region(simatic_ipc_batt_io_res.start, resource_size(&simatic_ipc_batt_io_res)); + + if (val & (1 << 7)) + r = SIMATIC_IPC_BATT_LEVEL_EMPTY; + else if (val & (1 << 6)) + r = SIMATIC_IPC_BATT_LEVEL_CRIT; + + return r; +} + +static long simatic_ipc_batt_read_value(struct device *dev) +{ + unsigned long next_update; + + next_update = priv.last_updated_jiffies + msecs_to_jiffies(BATT_DELAY_MS); + if (time_after(jiffies, next_update) || !priv.last_updated_jiffies) { + if (priv.devmode == SIMATIC_IPC_DEVICE_227E) + priv.current_state = simatic_ipc_batt_read_io(dev); + else + priv.current_state = simatic_ipc_batt_read_gpio(); + + priv.last_updated_jiffies = jiffies; + if (priv.current_state < SIMATIC_IPC_BATT_LEVEL_FULL) + dev_warn(dev, "CMOS battery needs to be replaced.\n"); + } + + return priv.current_state; +} + +static int simatic_ipc_batt_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + switch (attr) { + case hwmon_in_input: + *val = simatic_ipc_batt_read_value(dev); + break; + case hwmon_in_lcrit: + *val = SIMATIC_IPC_BATT_LEVEL_CRIT; + break; + default: + return -EOPNOTSUPP; + } + + return 0; +} + +static umode_t simatic_ipc_batt_is_visible(const void *data, enum hwmon_sensor_types type, + u32 attr, int channel) +{ + if (attr == hwmon_in_input || attr == hwmon_in_lcrit) + return 0444; + + return 0; +} + +static const struct hwmon_ops simatic_ipc_batt_ops = { + .is_visible = simatic_ipc_batt_is_visible, + .read = simatic_ipc_batt_read, +}; + +static const struct hwmon_channel_info *simatic_ipc_batt_info[] = { + HWMON_CHANNEL_INFO(in, HWMON_I_INPUT | HWMON_I_LCRIT), + NULL +}; + +static const struct hwmon_chip_info simatic_ipc_batt_chip_info = { + .ops = &simatic_ipc_batt_ops, + .info = simatic_ipc_batt_info, +}; + +int simatic_ipc_batt_remove(struct platform_device *pdev, struct gpiod_lookup_table *table) +{ + gpiod_remove_lookup_table(table); + return 0; +} +EXPORT_SYMBOL_GPL(simatic_ipc_batt_remove); + +int simatic_ipc_batt_probe(struct platform_device *pdev, struct gpiod_lookup_table *table) +{ + struct simatic_ipc_platform *plat; + struct device *dev = &pdev->dev; + struct device *hwmon_dev; + unsigned long flags; + int err; + + plat = pdev->dev.platform_data; + priv.devmode = plat->devmode; + + switch (priv.devmode) { + case SIMATIC_IPC_DEVICE_127E: + case SIMATIC_IPC_DEVICE_227G: + case SIMATIC_IPC_DEVICE_BX_39A: + case SIMATIC_IPC_DEVICE_BX_21A: + case SIMATIC_IPC_DEVICE_BX_59A: + table->dev_id = dev_name(dev); + gpiod_add_lookup_table(table); + break; + case SIMATIC_IPC_DEVICE_227E: + goto nogpio; + default: + return -ENODEV; + } + + priv.gpios[0] = devm_gpiod_get_index(dev, "CMOSBattery empty", 0, GPIOD_IN); + if (IS_ERR(priv.gpios[0])) { + err = PTR_ERR(priv.gpios[0]); + priv.gpios[0] = NULL; + goto out; + } + priv.gpios[1] = devm_gpiod_get_index(dev, "CMOSBattery low", 1, GPIOD_IN); + if (IS_ERR(priv.gpios[1])) { + err = PTR_ERR(priv.gpios[1]); + priv.gpios[1] = NULL; + goto out; + } + + if (table->table[2].key) { + flags = GPIOD_OUT_HIGH; + if (priv.devmode == SIMATIC_IPC_DEVICE_BX_21A || + priv.devmode == SIMATIC_IPC_DEVICE_BX_59A) + flags = GPIOD_OUT_LOW; + priv.gpios[2] = devm_gpiod_get_index(dev, "CMOSBattery meter", 2, flags); + if (IS_ERR(priv.gpios[2])) { + err = PTR_ERR(priv.gpios[2]); + priv.gpios[2] = NULL; + goto out; + } + } else { + priv.gpios[2] = NULL; + } + +nogpio: + hwmon_dev = devm_hwmon_device_register_with_info(dev, KBUILD_MODNAME, + &priv, + &simatic_ipc_batt_chip_info, + NULL); + if (IS_ERR(hwmon_dev)) { + err = PTR_ERR(hwmon_dev); + goto out; + } + + /* warn about aging battery even if userspace never reads hwmon */ + simatic_ipc_batt_read_value(dev); + + return 0; +out: + simatic_ipc_batt_remove(pdev, table); + + return err; +} +EXPORT_SYMBOL_GPL(simatic_ipc_batt_probe); + +static int simatic_ipc_batt_io_remove(struct platform_device *pdev) +{ + return simatic_ipc_batt_remove(pdev, NULL); +} + +static int simatic_ipc_batt_io_probe(struct platform_device *pdev) +{ + return simatic_ipc_batt_probe(pdev, NULL); +} + +static struct platform_driver simatic_ipc_batt_driver = { + .probe = simatic_ipc_batt_io_probe, + .remove = simatic_ipc_batt_io_remove, + .driver = { + .name = KBUILD_MODNAME, + }, +}; + +module_platform_driver(simatic_ipc_batt_driver); + +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" KBUILD_MODNAME); +MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>"); |