power_supply: wilco_ec: Add charging config driver (3f57fe28) · Commits · e / devices / android_kernel_fairphone_FP5

Documentation/ABI/testing/sysfs-class-power-wilco

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		What: /sys/class/power_supply/wilco-charger/charge_type
		Date: April 2019
		KernelVersion: 5.2
		Description:
		What charging algorithm to use:

		Standard: Fully charges battery at a standard rate.
		Adaptive: Battery settings adaptively optimized based on
		typical battery usage pattern.
		Fast: Battery charges over a shorter period.
		Trickle: Extends battery lifespan, intended for users who
		primarily use their Chromebook while connected to AC.
		Custom: A low and high threshold percentage is specified.
		Charging begins when level drops below
		charge_control_start_threshold, and ceases when
		level is above charge_control_end_threshold.

		What: /sys/class/power_supply/wilco-charger/charge_control_start_threshold
		Date: April 2019
		KernelVersion: 5.2
		Description:
		Used when charge_type="Custom", as described above. Measured in
		percentages. The valid range is [50, 95].

		What: /sys/class/power_supply/wilco-charger/charge_control_end_threshold
		Date: April 2019
		KernelVersion: 5.2
		Description:
		Used when charge_type="Custom", as described above. Measured in
		percentages. The valid range is [55, 100].

drivers/power/supply/Kconfig

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		@@ -702,4 +702,13 @@ config CHARGER_UCS1002
		Say Y to enable support for Microchip UCS1002 Programmable
		USB Port Power Controller with Charger Emulation.

		config CHARGER_WILCO
		tristate "Wilco EC based charger for ChromeOS"
		depends on WILCO_EC
		help
		Say Y here to enable control of the charging routines performed
		by the Embedded Controller on the Chromebook named Wilco. Further
		information can be found in
		Documentation/ABI/testing/sysfs-class-power-wilco

		endif # POWER_SUPPLY

drivers/power/supply/Makefile

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		@@ -91,3 +91,4 @@ obj-$(CONFIG_CHARGER_CROS_USBPD) += cros_usbpd-charger.o
		obj-$(CONFIG_CHARGER_SC2731) += sc2731_charger.o
		obj-$(CONFIG_FUEL_GAUGE_SC27XX) += sc27xx_fuel_gauge.o
		obj-$(CONFIG_CHARGER_UCS1002) += ucs1002_power.o
		obj-$(CONFIG_CHARGER_WILCO) += wilco-charger.o

drivers/power/supply/wilco-charger.c

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		// SPDX-License-Identifier: GPL-2.0
		/*
		* Charging control driver for the Wilco EC
		*
		* Copyright 2019 Google LLC
		*
		* See Documentation/ABI/testing/sysfs-class-power and
		* Documentation/ABI/testing/sysfs-class-power-wilco for userspace interface
		* and other info.
		*/

		#include <linux/module.h>
		#include <linux/platform_device.h>
		#include <linux/platform_data/wilco-ec.h>
		#include <linux/power_supply.h>

		#define DRV_NAME "wilco-charger"

		/* Property IDs and related EC constants */
		#define PID_CHARGE_MODE 0x0710
		#define PID_CHARGE_LOWER_LIMIT 0x0711
		#define PID_CHARGE_UPPER_LIMIT 0x0712

		enum charge_mode {
		CHARGE_MODE_STD = 1, /* Used for Standard */
		CHARGE_MODE_EXP = 2, /* Express Charge, used for Fast */
		CHARGE_MODE_AC = 3, /* Mostly AC use, used for Trickle */
		CHARGE_MODE_AUTO = 4, /* Used for Adaptive */
		CHARGE_MODE_CUSTOM = 5, /* Used for Custom */
		};

		#define CHARGE_LOWER_LIMIT_MIN 50
		#define CHARGE_LOWER_LIMIT_MAX 95
		#define CHARGE_UPPER_LIMIT_MIN 55
		#define CHARGE_UPPER_LIMIT_MAX 100

		/* Convert from POWER_SUPPLY_PROP_CHARGE_TYPE value to the EC's charge mode */
		static int psp_val_to_charge_mode(int psp_val)
		{
		switch (psp_val) {
		case POWER_SUPPLY_CHARGE_TYPE_TRICKLE:
		return CHARGE_MODE_AC;
		case POWER_SUPPLY_CHARGE_TYPE_FAST:
		return CHARGE_MODE_EXP;
		case POWER_SUPPLY_CHARGE_TYPE_STANDARD:
		return CHARGE_MODE_STD;
		case POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE:
		return CHARGE_MODE_AUTO;
		case POWER_SUPPLY_CHARGE_TYPE_CUSTOM:
		return CHARGE_MODE_CUSTOM;
		default:
		return -EINVAL;
		}
		}

		/* Convert from EC's charge mode to POWER_SUPPLY_PROP_CHARGE_TYPE value */
		static int charge_mode_to_psp_val(enum charge_mode mode)
		{
		switch (mode) {
		case CHARGE_MODE_AC:
		return POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
		case CHARGE_MODE_EXP:
		return POWER_SUPPLY_CHARGE_TYPE_FAST;
		case CHARGE_MODE_STD:
		return POWER_SUPPLY_CHARGE_TYPE_STANDARD;
		case CHARGE_MODE_AUTO:
		return POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE;
		case CHARGE_MODE_CUSTOM:
		return POWER_SUPPLY_CHARGE_TYPE_CUSTOM;
		default:
		return -EINVAL;
		}
		}

		static enum power_supply_property wilco_charge_props[] = {
		POWER_SUPPLY_PROP_CHARGE_TYPE,
		POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD,
		POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD,
		};

		static int wilco_charge_get_property(struct power_supply *psy,
		enum power_supply_property psp,
		union power_supply_propval *val)
		{
		struct wilco_ec_device *ec = power_supply_get_drvdata(psy);
		u32 property_id;
		int ret;
		u8 raw;

		switch (psp) {
		case POWER_SUPPLY_PROP_CHARGE_TYPE:
		property_id = PID_CHARGE_MODE;
		break;
		case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
		property_id = PID_CHARGE_LOWER_LIMIT;
		break;
		case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
		property_id = PID_CHARGE_UPPER_LIMIT;
		break;
		default:
		return -EINVAL;
		}

		ret = wilco_ec_get_byte_property(ec, property_id, &raw);
		if (ret < 0)
		return ret;
		if (property_id == PID_CHARGE_MODE) {
		ret = charge_mode_to_psp_val(raw);
		if (ret < 0)
		return -EBADMSG;
		raw = ret;
		}
		val->intval = raw;

		return 0;
		}

		static int wilco_charge_set_property(struct power_supply *psy,
		enum power_supply_property psp,
		const union power_supply_propval *val)
		{
		struct wilco_ec_device *ec = power_supply_get_drvdata(psy);
		int mode;

		switch (psp) {
		case POWER_SUPPLY_PROP_CHARGE_TYPE:
		mode = psp_val_to_charge_mode(val->intval);
		if (mode < 0)
		return -EINVAL;
		return wilco_ec_set_byte_property(ec, PID_CHARGE_MODE, mode);
		case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
		if (val->intval < CHARGE_LOWER_LIMIT_MIN \|\|
		val->intval > CHARGE_LOWER_LIMIT_MAX)
		return -EINVAL;
		return wilco_ec_set_byte_property(ec, PID_CHARGE_LOWER_LIMIT,
		val->intval);
		case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
		if (val->intval < CHARGE_UPPER_LIMIT_MIN \|\|
		val->intval > CHARGE_UPPER_LIMIT_MAX)
		return -EINVAL;
		return wilco_ec_set_byte_property(ec, PID_CHARGE_UPPER_LIMIT,
		val->intval);
		default:
		return -EINVAL;
		}
		}

		static int wilco_charge_property_is_writeable(struct power_supply *psy,
		enum power_supply_property psp)
		{
		return 1;
		}

		static const struct power_supply_desc wilco_ps_desc = {
		.properties = wilco_charge_props,
		.num_properties = ARRAY_SIZE(wilco_charge_props),
		.get_property = wilco_charge_get_property,
		.set_property = wilco_charge_set_property,
		.property_is_writeable = wilco_charge_property_is_writeable,
		.name = DRV_NAME,
		.type = POWER_SUPPLY_TYPE_MAINS,
		};

		static int wilco_charge_probe(struct platform_device *pdev)
		{
		struct wilco_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
		struct power_supply_config psy_cfg = {};
		struct power_supply *psy;

		psy_cfg.drv_data = ec;
		psy = devm_power_supply_register(&pdev->dev, &wilco_ps_desc, &psy_cfg);

		return PTR_ERR_OR_ZERO(psy);
		}

		static struct platform_driver wilco_charge_driver = {
		.probe = wilco_charge_probe,
		.driver = {
		.name = DRV_NAME,
		}
		};
		module_platform_driver(wilco_charge_driver);

		MODULE_ALIAS("platform:" DRV_NAME);
		MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>");
		MODULE_LICENSE("GPL v2");
		MODULE_DESCRIPTION("Wilco EC charge control driver");