diff options
Diffstat (limited to 'drivers/platform/x86/x86-android-tablets/vexia_atla10_ec.c')
| -rw-r--r-- | drivers/platform/x86/x86-android-tablets/vexia_atla10_ec.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/drivers/platform/x86/x86-android-tablets/vexia_atla10_ec.c b/drivers/platform/x86/x86-android-tablets/vexia_atla10_ec.c new file mode 100644 index 000000000000..5d02af1c5aaa --- /dev/null +++ b/drivers/platform/x86/x86-android-tablets/vexia_atla10_ec.c @@ -0,0 +1,261 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * power_supply class (battery) driver for the I2C attached embedded controller + * found on Vexia EDU ATLA 10 (9V version) tablets. + * + * This is based on the ACPI Battery device in the DSDT which should work + * expect that it expects the I2C controller to be enumerated as an ACPI + * device and the tablet's BIOS enumerates all LPSS devices as PCI devices + * (and changing the LPSS BIOS settings from PCI -> ACPI does not work). + * + * Copyright (c) 2024 Hans de Goede <hansg@kernel.org> + */ + +#include <linux/bits.h> +#include <linux/devm-helpers.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/power_supply.h> +#include <linux/types.h> +#include <linux/workqueue.h> + +#include <asm/byteorder.h> + +/* State field uses ACPI Battery spec status bits */ +#define ACPI_BATTERY_STATE_DISCHARGING BIT(0) +#define ACPI_BATTERY_STATE_CHARGING BIT(1) + +#define ATLA10_EC_BATTERY_STATE_COMMAND 0x87 +#define ATLA10_EC_BATTERY_INFO_COMMAND 0x88 + +/* From broken ACPI battery device in DSDT */ +#define ATLA10_EC_VOLTAGE_MIN_DESIGN_uV 3750000 + +/* Update data every 5 seconds */ +#define UPDATE_INTERVAL_JIFFIES (5 * HZ) + +struct atla10_ec_battery_state { + u8 status; /* Using ACPI Battery spec status bits */ + u8 capacity; /* Percent */ + __le16 charge_now_mAh; + __le16 voltage_now_mV; + __le16 current_now_mA; + __le16 charge_full_mAh; + __le16 temp; /* centi degrees Celsius */ +} __packed; + +struct atla10_ec_battery_info { + __le16 charge_full_design_mAh; + __le16 voltage_now_mV; /* Should be design voltage, but is not ? */ + __le16 charge_full_design2_mAh; +} __packed; + +struct atla10_ec_data { + struct i2c_client *client; + struct power_supply *psy; + struct delayed_work work; + struct mutex update_lock; + struct atla10_ec_battery_info info; + struct atla10_ec_battery_state state; + bool valid; /* true if state is valid */ + unsigned long last_update; /* In jiffies */ +}; + +static int atla10_ec_cmd(struct atla10_ec_data *data, u8 cmd, u8 len, u8 *values) +{ + struct device *dev = &data->client->dev; + u8 buf[I2C_SMBUS_BLOCK_MAX]; + int ret; + + ret = i2c_smbus_read_block_data(data->client, cmd, buf); + if (ret != len) { + dev_err(dev, "I2C command 0x%02x error: %d\n", cmd, ret); + return -EIO; + } + + memcpy(values, buf, len); + return 0; +} + +static int atla10_ec_update(struct atla10_ec_data *data) +{ + int ret; + + if (data->valid && time_before(jiffies, data->last_update + UPDATE_INTERVAL_JIFFIES)) + return 0; + + ret = atla10_ec_cmd(data, ATLA10_EC_BATTERY_STATE_COMMAND, + sizeof(data->state), (u8 *)&data->state); + if (ret) + return ret; + + data->last_update = jiffies; + data->valid = true; + return 0; +} + +static int atla10_ec_psy_get_property(struct power_supply *psy, + enum power_supply_property psp, + union power_supply_propval *val) +{ + struct atla10_ec_data *data = power_supply_get_drvdata(psy); + int charge_now_mAh, charge_full_mAh, ret; + + guard(mutex)(&data->update_lock); + + ret = atla10_ec_update(data); + if (ret) + return ret; + + switch (psp) { + case POWER_SUPPLY_PROP_STATUS: + if (data->state.status & ACPI_BATTERY_STATE_DISCHARGING) + val->intval = POWER_SUPPLY_STATUS_DISCHARGING; + else if (data->state.status & ACPI_BATTERY_STATE_CHARGING) + val->intval = POWER_SUPPLY_STATUS_CHARGING; + else if (data->state.capacity == 100) + val->intval = POWER_SUPPLY_STATUS_FULL; + else + val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING; + break; + case POWER_SUPPLY_PROP_CAPACITY: + val->intval = data->state.capacity; + break; + case POWER_SUPPLY_PROP_CHARGE_NOW: + /* + * The EC has a bug where it reports charge-full-design as + * charge-now when the battery is full. Clamp charge-now to + * charge-full to workaround this. + */ + charge_now_mAh = le16_to_cpu(data->state.charge_now_mAh); + charge_full_mAh = le16_to_cpu(data->state.charge_full_mAh); + val->intval = min(charge_now_mAh, charge_full_mAh) * 1000; + break; + case POWER_SUPPLY_PROP_VOLTAGE_NOW: + val->intval = le16_to_cpu(data->state.voltage_now_mV) * 1000; + break; + case POWER_SUPPLY_PROP_CURRENT_NOW: + val->intval = le16_to_cpu(data->state.current_now_mA) * 1000; + /* + * Documentation/ABI/testing/sysfs-class-power specifies + * negative current for discharging. + */ + if (data->state.status & ACPI_BATTERY_STATE_DISCHARGING) + val->intval = -val->intval; + break; + case POWER_SUPPLY_PROP_CHARGE_FULL: + val->intval = le16_to_cpu(data->state.charge_full_mAh) * 1000; + break; + case POWER_SUPPLY_PROP_TEMP: + val->intval = le16_to_cpu(data->state.temp) / 10; + break; + case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: + val->intval = le16_to_cpu(data->info.charge_full_design_mAh) * 1000; + break; + case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN: + val->intval = ATLA10_EC_VOLTAGE_MIN_DESIGN_uV; + break; + case POWER_SUPPLY_PROP_PRESENT: + val->intval = 1; + break; + case POWER_SUPPLY_PROP_TECHNOLOGY: + val->intval = POWER_SUPPLY_TECHNOLOGY_LIPO; + break; + default: + return -EINVAL; + } + + return 0; +} + +static void atla10_ec_external_power_changed_work(struct work_struct *work) +{ + struct atla10_ec_data *data = container_of(work, struct atla10_ec_data, work.work); + + dev_dbg(&data->client->dev, "External power changed\n"); + data->valid = false; + power_supply_changed(data->psy); +} + +static void atla10_ec_external_power_changed(struct power_supply *psy) +{ + struct atla10_ec_data *data = power_supply_get_drvdata(psy); + + /* After charger plug in/out wait 0.5s for things to stabilize */ + mod_delayed_work(system_wq, &data->work, HZ / 2); +} + +static const enum power_supply_property atla10_ec_psy_props[] = { + POWER_SUPPLY_PROP_STATUS, + POWER_SUPPLY_PROP_CAPACITY, + POWER_SUPPLY_PROP_CHARGE_NOW, + POWER_SUPPLY_PROP_VOLTAGE_NOW, + POWER_SUPPLY_PROP_CURRENT_NOW, + POWER_SUPPLY_PROP_CHARGE_FULL, + POWER_SUPPLY_PROP_TEMP, + POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, + POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN, + POWER_SUPPLY_PROP_PRESENT, + POWER_SUPPLY_PROP_TECHNOLOGY, +}; + +static const struct power_supply_desc atla10_ec_psy_desc = { + .name = "atla10_ec_battery", + .type = POWER_SUPPLY_TYPE_BATTERY, + .properties = atla10_ec_psy_props, + .num_properties = ARRAY_SIZE(atla10_ec_psy_props), + .get_property = atla10_ec_psy_get_property, + .external_power_changed = atla10_ec_external_power_changed, +}; + +static int atla10_ec_probe(struct i2c_client *client) +{ + struct power_supply_config psy_cfg = { }; + struct device *dev = &client->dev; + struct atla10_ec_data *data; + int ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + psy_cfg.drv_data = data; + data->client = client; + + ret = devm_mutex_init(dev, &data->update_lock); + if (ret) + return ret; + + ret = devm_delayed_work_autocancel(dev, &data->work, + atla10_ec_external_power_changed_work); + if (ret) + return ret; + + ret = atla10_ec_cmd(data, ATLA10_EC_BATTERY_INFO_COMMAND, + sizeof(data->info), (u8 *)&data->info); + if (ret) + return ret; + + data->psy = devm_power_supply_register(dev, &atla10_ec_psy_desc, &psy_cfg); + return PTR_ERR_OR_ZERO(data->psy); +} + +static const struct i2c_device_id atla10_ec_id_table[] = { + { "vexia_atla10_ec" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, atla10_ec_id_table); + +static struct i2c_driver atla10_ec_driver = { + .driver = { + .name = "vexia_atla10_ec", + }, + .probe = atla10_ec_probe, + .id_table = atla10_ec_id_table, +}; +module_i2c_driver(atla10_ec_driver); + +MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>"); +MODULE_DESCRIPTION("Battery driver for Vexia EDU ATLA 10 tablet EC"); +MODULE_LICENSE("GPL"); |