[PATCH 17/22] power: supply: add battery driver for AXP20X and AXP22X PMICs

[Quentin Schulz <quentin.schulz@free-electrons.com>]

The X-Powers AXP20X and AXP22X PMICs can have a battery as power supply.

This patch adds the battery power supply driver to get various data from
the PMIC, such as the battery status (charging, discharging, full,
dead), current max limit, current current, battery capacity (in
percentage), voltage max and min limits, current voltage and battery
capacity (in Ah).

This battery driver uses the AXP20X/AXP22X ADC driver as PMIC data
provider.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
---
 drivers/power/supply/Kconfig          |  12 +
 drivers/power/supply/Makefile         |   1 +
 drivers/power/supply/axp20x_battery.c | 458 ++++++++++++++++++++++++++++++++++
 3 files changed, 471 insertions(+)
 create mode 100644 drivers/power/supply/axp20x_battery.c

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index c552b4b..48619de 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -226,6 +226,18 @@ config CHARGER_AXP20X
 	  This driver can also be built as a module. If so, the module will be
 	  called axp20x_ac_power.
 
+config BATTERY_AXP20X
+	tristate "X-Powers AXP20X battery driver"
+	depends on MFD_AXP20X
+	depends on AXP20X_ADC
+	depends on IIO
+	help
+	  Say Y here to enable support for X-Powers AXP20X PMICs' battery power
+	  supply.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called axp20x_battery.
+
 config AXP288_CHARGER
 	tristate "X-Powers AXP288 Charger"
 	depends on MFD_AXP20X && EXTCON_AXP288
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index 7d22417..5a217b2 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_TEST_POWER)	+= test_power.o
 
 obj-$(CONFIG_BATTERY_88PM860X)	+= 88pm860x_battery.o
 obj-$(CONFIG_BATTERY_ACT8945A)	+= act8945a_charger.o
+obj-$(CONFIG_BATTERY_AXP20X)	+= axp20x_battery.o
 obj-$(CONFIG_CHARGER_AXP20X)	+= axp20x_ac_power.o
 obj-$(CONFIG_BATTERY_DS2760)	+= ds2760_battery.o
 obj-$(CONFIG_BATTERY_DS2780)	+= ds2780_battery.o
diff --git a/drivers/power/supply/axp20x_battery.c b/drivers/power/supply/axp20x_battery.c
new file mode 100644
index 0000000..e1d7b5f
--- /dev/null
+++ b/drivers/power/supply/axp20x_battery.c
@@ -0,0 +1,458 @@
+/*
+ * Battery power supply driver for X-Powers AXP20X and AXP22X PMICs
+ *
+ * Copyright 2016 Free Electrons NextThing Co.
+ *	Quentin Schulz <quentin.schulz@free-electrons.com>
+ *
+ * This driver is based on a previous upstreaming attempt by:
+ *	Bruno Prémont <bonbons@linux-vserver.org>
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file "COPYING" in the main directory of this
+ * archive for more details.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/consumer.h>
+#include <linux/mfd/axp20x.h>
+
+#define AXP20X_PWR_STATUS_BAT_CHARGING	BIT(2)
+
+#define AXP20X_PWR_OP_BATT_PRESENT	BIT(5)
+#define AXP20X_PWR_OP_BATT_ACTIVATED	BIT(3)
+
+#define AXP209_FG_PERCENT		GENMASK(6, 0)
+#define AXP22X_FG_VALID			BIT(7)
+
+#define AXP20X_CHRG_CTRL1_TGT_VOLT	GENMASK(6, 5)
+#define AXP20X_CHRG_CTRL1_TGT_4_1V	(0 << 5)
+#define AXP20X_CHRG_CTRL1_TGT_4_15V	BIT(5)
+#define AXP20X_CHRG_CTRL1_TGT_4_2V	(2 << 5)
+#define AXP20X_CHRG_CTRL1_TGT_4_36V	(3 << 5)
+#define AXP20X_CHRG_CTRL1_TGT_CURR	GENMASK(3, 0)
+
+#define AXP22X_CHRG_CTRL1_TGT_4_22V	BIT(5)
+#define AXP22X_CHRG_CTRL1_TGT_4_24V	(3 << 5)
+
+#define AXP20X_V_OFF_MASK		GENMASK(2, 0)
+
+struct axp20x_batt_ps {
+	struct regmap *regmap;
+	struct power_supply *batt;
+	struct axp20x_dev *axp20x;
+	struct iio_channel *batt_chrg_i;
+	struct iio_channel *batt_dischrg_i;
+	struct iio_channel *batt_v;
+	u8 axp_id;
+};
+
+static int axp20x_battery_get_max_voltage(struct axp20x_batt_ps *axp20x_batt,
+					  int *val)
+{
+	int ret, reg;
+
+	ret = regmap_read(axp20x_batt->regmap, AXP20X_CHRG_CTRL1, &reg);
+	if (ret)
+		return ret;
+
+	switch (reg & AXP20X_CHRG_CTRL1_TGT_VOLT) {
+	case AXP20X_CHRG_CTRL1_TGT_4_1V:
+		*val = 4100000;
+		break;
+	case AXP20X_CHRG_CTRL1_TGT_4_15V:
+		*val = 4150000;
+		break;
+	case AXP20X_CHRG_CTRL1_TGT_4_2V:
+		*val = 4200000;
+		break;
+	case AXP20X_CHRG_CTRL1_TGT_4_36V:
+		*val = 4360000;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int axp22x_battery_get_max_voltage(struct axp20x_batt_ps *axp20x_batt,
+					  int *val)
+{
+	int ret, reg;
+
+	ret = regmap_read(axp20x_batt->regmap, AXP20X_CHRG_CTRL1, &reg);
+	if (ret)
+		return ret;
+
+	switch (reg & AXP20X_CHRG_CTRL1_TGT_VOLT) {
+	case AXP20X_CHRG_CTRL1_TGT_4_1V:
+		*val = 4100000;
+		break;
+	case AXP20X_CHRG_CTRL1_TGT_4_2V:
+		*val = 4200000;
+		break;
+	case AXP22X_CHRG_CTRL1_TGT_4_22V:
+		*val = 4220000;
+		break;
+	case AXP22X_CHRG_CTRL1_TGT_4_24V:
+		*val = 4240000;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int axp20x_battery_get_prop(struct power_supply *psy,
+				   enum power_supply_property psp,
+				   union power_supply_propval *val)
+{
+	struct axp20x_batt_ps *axp20x_batt = power_supply_get_drvdata(psy);
+	struct iio_channel *chan;
+	int ret = 0, reg, val1;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_PRESENT:
+	case POWER_SUPPLY_PROP_ONLINE:
+		ret = regmap_read(axp20x_batt->regmap, AXP20X_PWR_OP_MODE,
+				  &reg);
+		if (ret)
+			return ret;
+
+		val->intval = !!(reg & AXP20X_PWR_OP_BATT_PRESENT);
+		break;
+
+	case POWER_SUPPLY_PROP_STATUS:
+		ret = regmap_read(axp20x_batt->regmap, AXP20X_PWR_INPUT_STATUS,
+				  &reg);
+		if (ret)
+			return ret;
+
+		if (reg & AXP20X_PWR_STATUS_BAT_CHARGING) {
+			val->intval = POWER_SUPPLY_STATUS_CHARGING;
+			return 0;
+		}
+
+		ret = iio_read_channel_processed(axp20x_batt->batt_dischrg_i,
+						 &val1);
+		if (ret)
+			return ret;
+
+		if (val1) {
+			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+			return 0;
+		}
+
+		ret = regmap_read(axp20x_batt->regmap, AXP20X_FG_RES, &val1);
+		if (ret)
+			return ret;
+
+		/*
+		 * Fuel Gauge data takes 7 bits but the stored value seems to be
+		 * directly the raw percentage without any scaling to 7 bits.
+		 */
+		if ((val1 & AXP209_FG_PERCENT) == 100)
+			val->intval = POWER_SUPPLY_STATUS_FULL;
+		else
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+		break;
+
+	case POWER_SUPPLY_PROP_HEALTH:
+		ret = regmap_read(axp20x_batt->regmap, AXP20X_PWR_OP_MODE,
+				  &val1);
+		if (ret)
+			return ret;
+
+		if (val1 & AXP20X_PWR_OP_BATT_ACTIVATED) {
+			val->intval = POWER_SUPPLY_HEALTH_DEAD;
+			return 0;
+		}
+
+		val->intval = POWER_SUPPLY_HEALTH_GOOD;
+		break;
+
+	case POWER_SUPPLY_PROP_CURRENT_MAX:
+		ret = regmap_read(axp20x_batt->regmap, AXP20X_CHRG_CTRL1, &reg);
+		if (ret)
+			return ret;
+
+		reg &= AXP20X_CHRG_CTRL1_TGT_CURR;
+		val->intval = reg * 100000 + 300000;
+		break;
+
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		ret = regmap_read(axp20x_batt->regmap, AXP20X_PWR_INPUT_STATUS,
+				  &reg);
+		if (ret)
+			return ret;
+
+		if (reg & AXP20X_PWR_STATUS_BAT_CHARGING)
+			chan = axp20x_batt->batt_chrg_i;
+		else
+			chan = axp20x_batt->batt_dischrg_i;
+
+		ret = iio_read_channel_processed(chan, &val->intval);
+		if (ret)
+			return ret;
+
+		/*
+		 * IIO framework gives mV but Power Supply framework gives µV.
+		 */
+		val->intval *= 1000;
+		break;
+
+	case POWER_SUPPLY_PROP_CAPACITY:
+		/* When no battery is present, return capacity is 100% */
+		ret = regmap_read(axp20x_batt->regmap, AXP20X_PWR_OP_MODE,
+				  &reg);
+		if (ret)
+			return ret;
+
+		if (!(reg & AXP20X_PWR_OP_BATT_PRESENT)) {
+			val->intval = 100;
+			return 0;
+		}
+
+		ret = regmap_read(axp20x_batt->regmap, AXP20X_FG_RES, &reg);
+		if (ret)
+			return ret;
+
+		if (axp20x_batt->axp_id == AXP221_ID &&
+		    !(reg & AXP22X_FG_VALID))
+			return -EINVAL;
+
+		/*
+		 * Fuel Gauge data takes 7 bits but the stored value seems to be
+		 * directly the raw percentage without any scaling to 7 bits.
+		 */
+		val->intval = reg & AXP209_FG_PERCENT;
+		break;
+
+	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
+		if (axp20x_batt->axp_id == AXP209_ID)
+			return axp20x_battery_get_max_voltage(axp20x_batt,
+							      &val->intval);
+		return axp22x_battery_get_max_voltage(axp20x_batt,
+						      &val->intval);
+
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
+		ret = regmap_read(axp20x_batt->regmap, AXP20X_V_OFF, &reg);
+		if (ret)
+			return ret;
+
+		val->intval = 2600000 + 100000 * (reg & AXP20X_V_OFF_MASK);
+		break;
+
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		ret = iio_read_channel_processed(axp20x_batt->batt_v,
+						 &val->intval);
+		if (ret)
+			return ret;
+
+		/*
+		 * IIO framework gives mV but Power Supply framework gives µV.
+		 */
+		val->intval *= 1000;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int axp20x_battery_set_max_voltage(struct axp20x_batt_ps *axp20x_batt,
+					  int val)
+{
+	switch (val) {
+	case 4100000:
+		return regmap_update_bits(axp20x_batt->regmap,
+					  AXP20X_CHRG_CTRL1,
+					  AXP20X_CHRG_CTRL1_TGT_VOLT,
+					  AXP20X_CHRG_CTRL1_TGT_4_1V);
+	case 4150000:
+		if (axp20x_batt->axp_id == AXP221_ID)
+			return -EINVAL;
+
+		return regmap_update_bits(axp20x_batt->regmap,
+					  AXP20X_CHRG_CTRL1,
+					  AXP20X_CHRG_CTRL1_TGT_VOLT,
+					  AXP20X_CHRG_CTRL1_TGT_4_15V);
+	case 4200000:
+		return regmap_update_bits(axp20x_batt->regmap,
+					  AXP20X_CHRG_CTRL1,
+					  AXP20X_CHRG_CTRL1_TGT_VOLT,
+					  AXP20X_CHRG_CTRL1_TGT_4_2V);
+	default:
+		/*
+		 * AXP20x max voltage can be set to 4.36V and AXP22X max voltage
+		 * can be set to 4.22V and 4.24V, but these voltages are too
+		 * high for Lithium based batteries (AXP PMICs are supposed to
+		 * be used with these kinds of battery).
+		 */
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int axp20x_battery_set_prop(struct power_supply *psy,
+				   enum power_supply_property psp,
+				   const union power_supply_propval *val)
+{
+	struct axp20x_batt_ps *axp20x_batt = power_supply_get_drvdata(psy);
+	int ret = 0, val1;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
+		val1 = (val->intval - 2600000) / 100000;
+		if (val1 < 0 || val1 > AXP20X_V_OFF_MASK)
+			return -EINVAL;
+
+		return regmap_update_bits(axp20x_batt->regmap, AXP20X_V_OFF,
+					  AXP20X_V_OFF_MASK, val1);
+
+	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
+		return axp20x_battery_set_max_voltage(axp20x_batt, val->intval);
+
+	case POWER_SUPPLY_PROP_CURRENT_MAX:
+		if (axp20x_batt->axp_id == AXP209_ID)
+			val1 = (val->intval - 300000) / 100000;
+		else
+			val1 = (val->intval - 300000) / 150000;
+
+		if (val1 > AXP20X_CHRG_CTRL1_TGT_CURR || val1 < 0)
+			return -EINVAL;
+
+		return regmap_update_bits(axp20x_batt->regmap,
+					  AXP20X_CHRG_CTRL1,
+					  AXP20X_CHRG_CTRL1_TGT_CURR, val1);
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static enum power_supply_property axp20x_battery_props[] = {
+	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_ONLINE,
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_CURRENT_MAX,
+	POWER_SUPPLY_PROP_HEALTH,
+	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
+	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
+	POWER_SUPPLY_PROP_CAPACITY,
+};
+
+static int axp20x_battery_prop_writeable(struct power_supply *psy,
+					 enum power_supply_property psp)
+{
+	return psp == POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN ||
+	       psp == POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN ||
+	       psp == POWER_SUPPLY_PROP_CURRENT_MAX;
+}
+
+static const struct power_supply_desc axp20x_batt_ps_desc = {
+	.name = "axp20x-battery",
+	.type = POWER_SUPPLY_TYPE_BATTERY,
+	.properties = axp20x_battery_props,
+	.num_properties = ARRAY_SIZE(axp20x_battery_props),
+	.property_is_writeable = axp20x_battery_prop_writeable,
+	.get_property = axp20x_battery_get_prop,
+	.set_property = axp20x_battery_set_prop,
+};
+
+static const struct of_device_id axp20x_battery_ps_id[] = {
+	{
+		.compatible = "x-powers,axp209-battery-power-supply",
+		.data = (void *)AXP209_ID,
+	}, {
+		.compatible = "x-powers,axp221-battery-power-supply",
+		.data = (void *)AXP221_ID,
+	}, { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, axp20x_battery_ps_id);
+
+static int axp20x_power_probe(struct platform_device *pdev)
+{
+	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
+	struct axp20x_batt_ps *axp20x_batt;
+	struct power_supply_config psy_cfg = {};
+
+	axp20x_batt = devm_kzalloc(&pdev->dev, sizeof(*axp20x_batt),
+				   GFP_KERNEL);
+	if (!axp20x_batt)
+		return -ENOMEM;
+
+	axp20x_batt->batt_v = devm_iio_channel_get(&pdev->dev, "batt_v");
+	if (IS_ERR(axp20x_batt->batt_v)) {
+		if (PTR_ERR(axp20x_batt->batt_v) == -ENODEV)
+			return -EPROBE_DEFER;
+		return PTR_ERR(axp20x_batt->batt_v);
+	}
+
+	axp20x_batt->batt_chrg_i = devm_iio_channel_get(&pdev->dev,
+							"batt_chrg_i");
+	if (IS_ERR(axp20x_batt->batt_chrg_i)) {
+		if (PTR_ERR(axp20x_batt->batt_chrg_i) == -ENODEV)
+			return -EPROBE_DEFER;
+		return PTR_ERR(axp20x_batt->batt_chrg_i);
+	}
+
+	axp20x_batt->batt_dischrg_i = devm_iio_channel_get(&pdev->dev,
+							   "batt_dischrg_i");
+	if (IS_ERR(axp20x_batt->batt_dischrg_i)) {
+		if (PTR_ERR(axp20x_batt->batt_dischrg_i) == -ENODEV)
+			return -EPROBE_DEFER;
+		return PTR_ERR(axp20x_batt->batt_dischrg_i);
+	}
+
+	axp20x_batt->regmap = axp20x->regmap;
+	platform_set_drvdata(pdev, axp20x_batt);
+
+	psy_cfg.drv_data = axp20x_batt;
+	psy_cfg.of_node = pdev->dev.of_node;
+
+	axp20x_batt->axp_id = (int)of_device_get_match_data(&pdev->dev);
+
+	axp20x_batt->batt = devm_power_supply_register(&pdev->dev,
+						       &axp20x_batt_ps_desc,
+						       &psy_cfg);
+	return PTR_ERR_OR_ZERO(axp20x_batt->batt);
+}
+
+static struct platform_driver axp20x_batt_driver = {
+	.probe    = axp20x_power_probe,
+	.driver   = {
+		.name  = "axp20x-battery-power-supply",
+		.of_match_table = axp20x_battery_ps_id,
+	},
+};
+
+module_platform_driver(axp20x_batt_driver);
+
+MODULE_DESCRIPTION("Battery power supply driver for AXP20X and AXP22X PMICs");
+MODULE_AUTHOR("Quentin Schulz <quentin.schulz@free-electrons.com>");
+MODULE_LICENSE("GPL");
-- 
2.9.3