This patch adds battery gauge driver for Acer Iconia Tab A500 device. The battery gauge function is provided via the Embedded Controller, which is found on the Acer A500.
Signed-off-by: Dmitry Osipenko <[email protected]> --- drivers/power/supply/Kconfig | 6 + drivers/power/supply/Makefile | 1 + drivers/power/supply/acer_a500_battery.c | 369 +++++++++++++++++++++++ 3 files changed, 376 insertions(+) create mode 100644 drivers/power/supply/acer_a500_battery.c diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig index faf2830aa152..dff5e5a7383f 100644 --- a/drivers/power/supply/Kconfig +++ b/drivers/power/supply/Kconfig @@ -752,4 +752,10 @@ config CHARGER_WILCO information can be found in Documentation/ABI/testing/sysfs-class-power-wilco +config BATTERY_ACER_A500 + tristate "Acer Iconia Tab A500 battery driver" + depends on MFD_ACER_A500_EC + help + Say Y to include support for Acer Iconia Tab A500 battery fuel gauge. + endif # POWER_SUPPLY diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile index b3c694a65114..08a5b49e2936 100644 --- a/drivers/power/supply/Makefile +++ b/drivers/power/supply/Makefile @@ -96,3 +96,4 @@ obj-$(CONFIG_CHARGER_UCS1002) += ucs1002_power.o obj-$(CONFIG_CHARGER_BD70528) += bd70528-charger.o obj-$(CONFIG_CHARGER_BD99954) += bd99954-charger.o obj-$(CONFIG_CHARGER_WILCO) += wilco-charger.o +obj-$(CONFIG_BATTERY_ACER_A500) += acer_a500_battery.o diff --git a/drivers/power/supply/acer_a500_battery.c b/drivers/power/supply/acer_a500_battery.c new file mode 100644 index 000000000000..933101e1261e --- /dev/null +++ b/drivers/power/supply/acer_a500_battery.c @@ -0,0 +1,369 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Battery driver for Acer Iconia Tab A500. + * + * Copyright 2020 GRATE-driver project. + * + * Based on downstream driver from Acer Inc. + * Based on NVIDIA Gas Gauge driver for SBS Compliant Batteries. + * + * Copyright (c) 2010, NVIDIA Corporation. + */ + +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/power_supply.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/workqueue.h> + +#include <linux/mfd/acer-ec-a500.h> + +#define BATTERY_SERIAL_LEN 22 + +enum { + REG_CAPACITY, + REG_VOLTAGE, + REG_CURRENT, + REG_DESIGN_CAPACITY, + REG_TEMPERATURE, + REG_SERIAL_NUMBER, +}; + +#define EC_DATA(_cmd, _delay, _psp) { \ + .psp = POWER_SUPPLY_PROP_ ## _psp, \ + .cmd = { \ + .cmd = _cmd, \ + .post_delay = _delay \ + }, \ +} + +static const struct chip_data { + enum power_supply_property psp; + struct a500_ec_cmd cmd; +} ec_data[] = { + [REG_CAPACITY] = EC_DATA(0x00, 0, CAPACITY), + [REG_VOLTAGE] = EC_DATA(0x01, 0, VOLTAGE_NOW), + [REG_CURRENT] = EC_DATA(0x03, 10, CURRENT_NOW), + [REG_DESIGN_CAPACITY] = EC_DATA(0x08, 0, CHARGE_FULL_DESIGN), + [REG_TEMPERATURE] = EC_DATA(0x0a, 0, TEMP), + [REG_SERIAL_NUMBER] = EC_DATA(0x6a, 0, SERIAL_NUMBER), +}; + +static const enum power_supply_property a500_battery_properties[] = { + POWER_SUPPLY_PROP_CAPACITY, + POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, + POWER_SUPPLY_PROP_CURRENT_NOW, + POWER_SUPPLY_PROP_PRESENT, + POWER_SUPPLY_PROP_SERIAL_NUMBER, + POWER_SUPPLY_PROP_STATUS, + POWER_SUPPLY_PROP_TECHNOLOGY, + POWER_SUPPLY_PROP_TEMP, + POWER_SUPPLY_PROP_VOLTAGE_NOW, +}; + +struct a500_battery { + struct delayed_work poll_work; + struct power_supply *psy; + struct a500_ec *ec_chip; + unsigned int capacity; + char serial[BATTERY_SERIAL_LEN + 1]; +}; + +static int a500_battery_get_presence(struct a500_battery *bat, + union power_supply_propval *val) +{ + s32 ret; + + /* + * DESIGN_CAPACITY register always returns a non-zero value if + * battery is connected and zero if disconnected. + */ + ret = a500_ec_read(bat->ec_chip, &ec_data[REG_DESIGN_CAPACITY].cmd); + if (ret <= 0) + val->intval = 0; + else + val->intval = 1; + + return 0; +} + +static bool a500_battery_update_capacity(struct a500_battery *bat) +{ + unsigned int capacity; + s32 ret; + + ret = a500_ec_read(bat->ec_chip, &ec_data[REG_CAPACITY].cmd); + if (ret < 0) + return false; + + /* capacity can be >100% even if max value is 100% */ + capacity = min(ret, 100); + + if (bat->capacity != capacity) { + bat->capacity = capacity; + return true; + } + + return false; +} + +static void a500_battery_get_status(struct a500_battery *bat, + union power_supply_propval *val) +{ + if (bat->capacity < 100) { + if (power_supply_am_i_supplied(bat->psy)) + val->intval = POWER_SUPPLY_STATUS_CHARGING; + else + val->intval = POWER_SUPPLY_STATUS_DISCHARGING; + } else { + val->intval = POWER_SUPPLY_STATUS_FULL; + } +} + +static void a500_battery_unit_adjustment(struct device *dev, + enum power_supply_property psp, + union power_supply_propval *val) +{ + const unsigned int base_unit_conversion = 1000; + const unsigned int temp_kelvin_to_celsius = 2731; + + switch (psp) { + case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: + case POWER_SUPPLY_PROP_CURRENT_NOW: + case POWER_SUPPLY_PROP_VOLTAGE_NOW: + val->intval *= base_unit_conversion; + break; + + case POWER_SUPPLY_PROP_TEMP: + val->intval -= temp_kelvin_to_celsius; + break; + + default: + dev_dbg(dev, + "%s: no need for unit conversion %d\n", __func__, psp); + } +} + +static int a500_battery_get_serial_number(struct a500_battery *bat, + union power_supply_propval *val) +{ + unsigned int i; + s32 ret = 0; + + if (bat->serial[0]) + goto done; + + a500_ec_lock(bat->ec_chip); + for (i = 0; i < BATTERY_SERIAL_LEN / 2; i++) { + ret = a500_ec_read_locked(bat->ec_chip, + &ec_data[REG_SERIAL_NUMBER].cmd); + if (ret < 0) { + bat->serial[0] = '\0'; + break; + } + + bat->serial[i * 2 + 0] = (ret >> 0) & 0xff; + bat->serial[i * 2 + 1] = (ret >> 8) & 0xff; + } + a500_ec_unlock(bat->ec_chip); +done: + val->strval = bat->serial; + + return ret; +} + +static int a500_battery_get_ec_data_index(struct device *dev, + enum power_supply_property psp) +{ + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(ec_data); i++) + if (psp == ec_data[i].psp) + return i; + + dev_dbg(dev, "%s: invalid property %u\n", __func__, psp); + + return -EINVAL; +} + +static int a500_battery_get_simple_property(struct a500_battery *bat, + union power_supply_propval *val, + unsigned int ec_idx) +{ + s32 ret; + + ret = a500_ec_read(bat->ec_chip, &ec_data[ec_idx].cmd); + if (ret < 0) + return ret; + + val->intval = (u16)ret; + + return 0; +} + +static int a500_battery_get_property(struct power_supply *psy, + enum power_supply_property psp, + union power_supply_propval *val) +{ + struct a500_battery *bat = power_supply_get_drvdata(psy); + struct device *dev = psy->dev.parent; + int ret = 0; + + switch (psp) { + case POWER_SUPPLY_PROP_SERIAL_NUMBER: + ret = a500_battery_get_serial_number(bat, val); + break; + + case POWER_SUPPLY_PROP_PRESENT: + ret = a500_battery_get_presence(bat, val); + break; + + case POWER_SUPPLY_PROP_STATUS: + a500_battery_get_status(bat, val); + break; + + case POWER_SUPPLY_PROP_TECHNOLOGY: + val->intval = POWER_SUPPLY_TECHNOLOGY_LION; + break; + + case POWER_SUPPLY_PROP_CAPACITY: + a500_battery_update_capacity(bat); + val->intval = bat->capacity; + break; + + case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: + case POWER_SUPPLY_PROP_CURRENT_NOW: + case POWER_SUPPLY_PROP_VOLTAGE_NOW: + case POWER_SUPPLY_PROP_TEMP: + ret = a500_battery_get_ec_data_index(dev, psp); + if (ret < 0) + break; + + ret = a500_battery_get_simple_property(bat, val, ret); + break; + + default: + dev_err(dev, "%s: invalid property %u\n", __func__, psp); + return -EINVAL; + } + + if (!ret) { + /* convert units to match requirements for power supply class */ + a500_battery_unit_adjustment(dev, psp, val); + } + + dev_dbg(dev, "%s: property = %d, value = %x\n", + __func__, psp, val->intval); + + /* return NODATA for properties if battery not presents */ + if (ret) + return -ENODATA; + + return 0; +} + +static void a500_battery_delayed_work(struct work_struct *work) +{ + struct a500_battery *bat; + bool capacity_changed; + + bat = container_of(work, struct a500_battery, poll_work.work); + capacity_changed = a500_battery_update_capacity(bat); + + if (capacity_changed) + power_supply_changed(bat->psy); + + /* continuously send uevent notification */ + schedule_delayed_work(&bat->poll_work, 30 * HZ); +} + +static const struct power_supply_desc a500_battery_desc = { + .name = "ec-battery", + .type = POWER_SUPPLY_TYPE_BATTERY, + .properties = a500_battery_properties, + .get_property = a500_battery_get_property, + .num_properties = ARRAY_SIZE(a500_battery_properties), + .external_power_changed = power_supply_changed, +}; + +static int a500_battery_probe(struct platform_device *pdev) +{ + struct power_supply_config psy_cfg = {}; + struct a500_battery *bat; + int err; + + bat = devm_kzalloc(&pdev->dev, sizeof(*bat), GFP_KERNEL); + if (!bat) + return -ENOMEM; + + platform_set_drvdata(pdev, bat); + + psy_cfg.of_node = pdev->dev.parent->of_node; + psy_cfg.drv_data = bat; + + bat->ec_chip = dev_get_drvdata(pdev->dev.parent); + + bat->psy = devm_power_supply_register_no_ws(&pdev->dev, + &a500_battery_desc, + &psy_cfg); + err = PTR_ERR_OR_ZERO(bat->psy); + if (err) { + if (err == -EPROBE_DEFER) + dev_dbg(&pdev->dev, "failed to register battery, deferring probe\n"); + else + dev_err(&pdev->dev, "failed to register battery: %d\n", + err); + return err; + } + + INIT_DELAYED_WORK(&bat->poll_work, a500_battery_delayed_work); + schedule_delayed_work(&bat->poll_work, HZ); + + return 0; +} + +static int a500_battery_remove(struct platform_device *pdev) +{ + struct a500_battery *bat = dev_get_drvdata(&pdev->dev); + + cancel_delayed_work_sync(&bat->poll_work); + + return 0; +} + +static int __maybe_unused a500_battery_suspend(struct device *dev) +{ + struct a500_battery *bat = dev_get_drvdata(dev); + + cancel_delayed_work_sync(&bat->poll_work); + + return 0; +} + +static int __maybe_unused a500_battery_resume(struct device *dev) +{ + struct a500_battery *bat = dev_get_drvdata(dev); + + schedule_delayed_work(&bat->poll_work, HZ); + + return 0; +} + +static SIMPLE_DEV_PM_OPS(a500_battery_pm_ops, + a500_battery_suspend, a500_battery_resume); + +static struct platform_driver a500_battery_driver = { + .driver = { + .name = "acer-a500-iconia-battery", + .pm = &a500_battery_pm_ops, + }, + .probe = a500_battery_probe, + .remove = a500_battery_remove, +}; +module_platform_driver(a500_battery_driver); + +MODULE_DESCRIPTION("Battery gauge driver for Acer Iconia Tab A500"); +MODULE_AUTHOR("Dmitry Osipenko <[email protected]>"); +MODULE_ALIAS("platform:acer-a500-iconia-battery"); +MODULE_LICENSE("GPL v2"); -- 2.27.0
