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linux/drivers/power/supply/chagall-battery.c
Svyatoslav Ryhel fbc1d056d3 power: supply: Add driver for Pegatron Chagall battery 
The Pegatron Chagall is an Android tablet utilizing a customized Cypress
CG7153AM microcontroller (MCU) as its battery fuel gauge. It supports a
single-cell battery and features a dual-color charging LED.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Link: https://lore.kernel.org/r/20250429061803.9581-4-clamor95@gmail.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2025-04-30 00:02:18 +02:00

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// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/array_size.h>
#include <linux/delay.h>
#include <linux/devm-helpers.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/leds.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/power_supply.h>
#include <linux/regmap.h>
#define CHAGALL_REG_LED_AMBER 0x60
#define CHAGALL_REG_LED_WHITE 0x70
#define CHAGALL_REG_BATTERY_TEMPERATURE 0xa2
#define CHAGALL_REG_BATTERY_VOLTAGE 0xa4
#define CHAGALL_REG_BATTERY_CURRENT 0xa6
#define CHAGALL_REG_BATTERY_CAPACITY 0xa8
#define CHAGALL_REG_BATTERY_CHARGING_CURRENT 0xaa
#define CHAGALL_REG_BATTERY_CHARGING_VOLTAGE 0xac
#define CHAGALL_REG_BATTERY_STATUS 0xae
#define BATTERY_DISCHARGING BIT(6)
#define BATTERY_FULL_CHARGED BIT(5)
#define BATTERY_FULL_DISCHARGED BIT(4)
#define CHAGALL_REG_BATTERY_REMAIN_CAPACITY 0xb0
#define CHAGALL_REG_BATTERY_FULL_CAPACITY 0xb2
#define CHAGALL_REG_MAX_COUNT 0xb4
#define CHAGALL_BATTERY_DATA_REFRESH 5000
#define TEMP_CELSIUS_OFFSET 2731
static const struct regmap_config chagall_battery_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = CHAGALL_REG_MAX_COUNT,
.reg_format_endian = REGMAP_ENDIAN_LITTLE,
.val_format_endian = REGMAP_ENDIAN_LITTLE,
};
struct chagall_battery_data {
struct regmap *regmap;
struct led_classdev amber_led;
struct led_classdev white_led;
struct power_supply *battery;
struct delayed_work poll_work;
u16 last_state;
};
static void chagall_led_set_brightness_amber(struct led_classdev *led,
enum led_brightness brightness)
{
struct chagall_battery_data *cg =
container_of(led, struct chagall_battery_data, amber_led);
regmap_write(cg->regmap, CHAGALL_REG_LED_AMBER, brightness);
}
static void chagall_led_set_brightness_white(struct led_classdev *led,
enum led_brightness brightness)
{
struct chagall_battery_data *cg =
container_of(led, struct chagall_battery_data, white_led);
regmap_write(cg->regmap, CHAGALL_REG_LED_WHITE, brightness);
}
static const enum power_supply_property chagall_battery_properties[] = {
POWER_SUPPLY_PROP_STATUS,
POWER_SUPPLY_PROP_PRESENT,
POWER_SUPPLY_PROP_VOLTAGE_NOW,
POWER_SUPPLY_PROP_VOLTAGE_MAX,
POWER_SUPPLY_PROP_CURRENT_NOW,
POWER_SUPPLY_PROP_CURRENT_MAX,
POWER_SUPPLY_PROP_CAPACITY,
POWER_SUPPLY_PROP_TEMP,
POWER_SUPPLY_PROP_CHARGE_FULL,
POWER_SUPPLY_PROP_CHARGE_NOW,
};
static const unsigned int chagall_battery_prop_offs[] = {
[POWER_SUPPLY_PROP_STATUS] = CHAGALL_REG_BATTERY_STATUS,
[POWER_SUPPLY_PROP_VOLTAGE_NOW] = CHAGALL_REG_BATTERY_VOLTAGE,
[POWER_SUPPLY_PROP_VOLTAGE_MAX] = CHAGALL_REG_BATTERY_CHARGING_VOLTAGE,
[POWER_SUPPLY_PROP_CURRENT_NOW] = CHAGALL_REG_BATTERY_CURRENT,
[POWER_SUPPLY_PROP_CURRENT_MAX] = CHAGALL_REG_BATTERY_CHARGING_CURRENT,
[POWER_SUPPLY_PROP_CAPACITY] = CHAGALL_REG_BATTERY_CAPACITY,
[POWER_SUPPLY_PROP_TEMP] = CHAGALL_REG_BATTERY_TEMPERATURE,
[POWER_SUPPLY_PROP_CHARGE_FULL] = CHAGALL_REG_BATTERY_FULL_CAPACITY,
[POWER_SUPPLY_PROP_CHARGE_NOW] = CHAGALL_REG_BATTERY_REMAIN_CAPACITY,
};
static int chagall_battery_get_value(struct chagall_battery_data *cg,
enum power_supply_property psp, u32 *val)
{
if (psp >= ARRAY_SIZE(chagall_battery_prop_offs))
return -EINVAL;
if (!chagall_battery_prop_offs[psp])
return -EINVAL;
/* Battery data is stored in 2 consecutive registers with little-endian */
return regmap_bulk_read(cg->regmap, chagall_battery_prop_offs[psp], val, 2);
}
static int chagall_battery_get_status(u32 status_reg)
{
if (status_reg & BATTERY_FULL_CHARGED)
return POWER_SUPPLY_STATUS_FULL;
else if (status_reg & BATTERY_DISCHARGING)
return POWER_SUPPLY_STATUS_DISCHARGING;
else
return POWER_SUPPLY_STATUS_CHARGING;
}
static int chagall_battery_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct chagall_battery_data *cg = power_supply_get_drvdata(psy);
int ret;
switch (psp) {
case POWER_SUPPLY_PROP_PRESENT:
val->intval = 1;
break;
default:
ret = chagall_battery_get_value(cg, psp, &val->intval);
if (ret)
return ret;
switch (psp) {
case POWER_SUPPLY_PROP_TEMP:
val->intval -= TEMP_CELSIUS_OFFSET;
break;
case POWER_SUPPLY_PROP_VOLTAGE_MAX:
case POWER_SUPPLY_PROP_VOLTAGE_NOW:
case POWER_SUPPLY_PROP_CURRENT_MAX:
case POWER_SUPPLY_PROP_CURRENT_NOW:
case POWER_SUPPLY_PROP_CHARGE_FULL:
case POWER_SUPPLY_PROP_CHARGE_NOW:
val->intval *= 1000;
break;
case POWER_SUPPLY_PROP_STATUS:
val->intval = chagall_battery_get_status(val->intval);
break;
default:
break;
}
break;
}
return 0;
}
static void chagall_battery_poll_work(struct work_struct *work)
{
struct chagall_battery_data *cg =
container_of(work, struct chagall_battery_data, poll_work.work);
u32 state;
int ret;
ret = chagall_battery_get_value(cg, POWER_SUPPLY_PROP_STATUS, &state);
if (ret)
return;
state = chagall_battery_get_status(state);
if (cg->last_state != state) {
cg->last_state = state;
power_supply_changed(cg->battery);
}
/* continuously send uevent notification */
schedule_delayed_work(&cg->poll_work,
msecs_to_jiffies(CHAGALL_BATTERY_DATA_REFRESH));
}
static const struct power_supply_desc chagall_battery_desc = {
.name = "chagall-battery",
.type = POWER_SUPPLY_TYPE_BATTERY,
.properties = chagall_battery_properties,
.num_properties = ARRAY_SIZE(chagall_battery_properties),
.get_property = chagall_battery_get_property,
.external_power_changed = power_supply_changed,
};
static int chagall_battery_probe(struct i2c_client *client)
{
struct chagall_battery_data *cg;
struct device *dev = &client->dev;
struct power_supply_config cfg = { };
int ret;
cg = devm_kzalloc(dev, sizeof(*cg), GFP_KERNEL);
if (!cg)
return -ENOMEM;
cfg.drv_data = cg;
cfg.fwnode = dev_fwnode(dev);
i2c_set_clientdata(client, cg);
cg->regmap = devm_regmap_init_i2c(client, &chagall_battery_regmap_config);
if (IS_ERR(cg->regmap))
return dev_err_probe(dev, PTR_ERR(cg->regmap), "cannot allocate regmap\n");
cg->last_state = POWER_SUPPLY_STATUS_UNKNOWN;
cg->battery = devm_power_supply_register(dev, &chagall_battery_desc, &cfg);
if (IS_ERR(cg->battery))
return dev_err_probe(dev, PTR_ERR(cg->battery),
"failed to register power supply\n");
cg->amber_led.name = "power::amber";
cg->amber_led.max_brightness = 1;
cg->amber_led.flags = LED_CORE_SUSPENDRESUME;
cg->amber_led.brightness_set = chagall_led_set_brightness_amber;
cg->amber_led.default_trigger = "chagall-battery-charging";
ret = devm_led_classdev_register(dev, &cg->amber_led);
if (ret)
return dev_err_probe(dev, ret, "failed to register amber LED\n");
cg->white_led.name = "power::white";
cg->white_led.max_brightness = 1;
cg->white_led.flags = LED_CORE_SUSPENDRESUME;
cg->white_led.brightness_set = chagall_led_set_brightness_white;
cg->white_led.default_trigger = "chagall-battery-full";
ret = devm_led_classdev_register(dev, &cg->white_led);
if (ret)
return dev_err_probe(dev, ret, "failed to register white LED\n");
led_set_brightness(&cg->amber_led, LED_OFF);
led_set_brightness(&cg->white_led, LED_OFF);
ret = devm_delayed_work_autocancel(dev, &cg->poll_work, chagall_battery_poll_work);
if (ret)
return ret;
schedule_delayed_work(&cg->poll_work, msecs_to_jiffies(CHAGALL_BATTERY_DATA_REFRESH));
return 0;
}
static int __maybe_unused chagall_battery_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct chagall_battery_data *cg = i2c_get_clientdata(client);
cancel_delayed_work_sync(&cg->poll_work);
return 0;
}
static int __maybe_unused chagall_battery_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct chagall_battery_data *cg = i2c_get_clientdata(client);
schedule_delayed_work(&cg->poll_work, msecs_to_jiffies(CHAGALL_BATTERY_DATA_REFRESH));
return 0;
}
static SIMPLE_DEV_PM_OPS(chagall_battery_pm_ops,
chagall_battery_suspend, chagall_battery_resume);
static const struct of_device_id chagall_of_match[] = {
{ .compatible = "pegatron,chagall-ec" },
{ }
};
MODULE_DEVICE_TABLE(of, chagall_of_match);
static struct i2c_driver chagall_battery_driver = {
.driver = {
.name = "chagall-battery",
.pm = &chagall_battery_pm_ops,
.of_match_table = chagall_of_match,
},
.probe = chagall_battery_probe,
};
module_i2c_driver(chagall_battery_driver);
MODULE_AUTHOR("Svyatoslav Ryhel <clamor95@gmail.com>");
MODULE_DESCRIPTION("Pegatron Chagall fuel gauge driver");
MODULE_LICENSE("GPL");
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