Re: [PATCH v3 13/18] power: supply: add battery driver for AXP20X and AXP22X PMICs

[Chen-Yu Tsai <wens@csie.org>]

On Tue, Feb 14, 2017 at 5:41 PM, Quentin Schulz
<quentin.schulz@free-electrons.com> wrote:
> 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>
> Acked-by: Jonathan Cameron <jic23@kernel.org>
> Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
>
> v3:
>  - added axp20x_set_voltage_min_design function so it can be reused,
>  - used power_supply_get_battery_info for setting constant charge current
>  instead of x-powers,constant-charge-current introduced in v2,
>  - used power_supply_get_battery_info for setting voltage min design of
>  the battery,
>
> v2:
>  - changed BIT(x) to 1 << x when describing bits purpose for which 2 <<
>  x or 3 << x exists, to be consistent,
>  - switched from POWER_SUPPLY_PROP_CURRENT_MAX to
>  POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
>  - added POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX to the list of
>  readable properties,
>  - replaced µ character by a common u for micro units to make checkpatch
>  happy,
>  - factorized code in axp20x_battery_set_max_voltage,
>  - added a axp20x_set_constant_charge_current function to be used when
>  setting the value from sysfs and from the DT,
>  - removed some dead code,
>  - added a DT property to set constant current charge of the battery
>  (x-powers,constant-charge-current),
>  - migrated to dev_get_regmap instead of manually looking for the regmap
>  in the drvdata of the parent,
>  - switched from int to uintptr_t cast to make sure the cast is always
>  for the same size type (make build on 64bits platforms happy mainly),
>  drivers/power/supply/Kconfig          |  12 +
>  drivers/power/supply/Makefile         |   1 +
>  drivers/power/supply/axp20x_battery.c | 492 ++++++++++++++++++++++++++++++++++
>  3 files changed, 505 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..bd16ac6
> --- /dev/null
> +++ b/drivers/power/supply/axp20x_battery.c
> @@ -0,0 +1,492 @@
> +/*
> + * 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    (1 << 5)
> +#define AXP20X_CHRG_CTRL1_TGT_4_2V     (2 << 5)
> +#define AXP20X_CHRG_CTRL1_TGT_4_36V    (3 << 5)
> +
> +#define AXP22X_CHRG_CTRL1_TGT_4_22V    (1 << 5)
> +#define AXP22X_CHRG_CTRL1_TGT_4_24V    (3 << 5)
> +
> +#define AXP20X_CHRG_CTRL1_TGT_CURR     GENMASK(3, 0)
> +
> +#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_CONSTANT_CHARGE_CURRENT:
> +               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_CONSTANT_CHARGE_CURRENT_MAX:
> +               val->intval = AXP20X_CHRG_CTRL1_TGT_CURR * 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 mA but Power Supply framework gives uA */
> +               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 uV */
> +               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:
> +               val = AXP20X_CHRG_CTRL1_TGT_4_1V;
> +               break;
> +
> +       case 4150000:
> +               if (axp20x_batt->axp_id == AXP221_ID)
> +                       return -EINVAL;
> +
> +               val = AXP20X_CHRG_CTRL1_TGT_4_15V;
> +               break;
> +
> +       case 4200000:
> +               val = AXP20X_CHRG_CTRL1_TGT_4_2V;
> +               break;
> +
> +       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 regmap_update_bits(axp20x_batt->regmap, AXP20X_CHRG_CTRL1,
> +                                 AXP20X_CHRG_CTRL1_TGT_VOLT, val);
> +}
> +
> +static int axp20x_set_constant_charge_current(struct axp20x_batt_ps *axp_batt,
> +                                             int charge_current)
> +{
> +       if (axp_batt->axp_id == AXP209_ID)
> +               charge_current = (charge_current - 300000) / 100000;
> +       else
> +               charge_current = (charge_current - 300000) / 150000;
> +
> +       if (charge_current > AXP20X_CHRG_CTRL1_TGT_CURR || charge_current < 0)
> +               return -EINVAL;

I would add a check or warn if the value to be programmed exceeds that returned
by power_supply_get_battery_info. A charge current exceeding the limits of the
battery is potentially disastrous. The battery may be destroyed or even burst
into flames and explode, taking the board and anything nearby with it. Otherwise

Acked-by: Chen-Yu Tsai <wens@csie.org>

Speaking of power_supply_get_battery_info, is it merged or ready to be merged?

> +
> +       return regmap_update_bits(axp_batt->regmap, AXP20X_CHRG_CTRL1,
> +                                 AXP20X_CHRG_CTRL1_TGT_CURR, charge_current);
> +}
> +
> +static int axp20x_set_voltage_min_design(struct axp20x_batt_ps *axp_batt,
> +                                        int min_voltage)
> +{
> +       int val1 = (min_voltage - 2600000) / 100000;
> +
> +       if (val1 < 0 || val1 > AXP20X_V_OFF_MASK)
> +               return -EINVAL;
> +
> +       return regmap_update_bits(axp_batt->regmap, AXP20X_V_OFF,
> +                                 AXP20X_V_OFF_MASK, val1);
> +}
> +
> +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);
> +
> +       switch (psp) {
> +       case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
> +               return axp20x_set_voltage_min_design(axp20x_batt, val->intval);
> +
> +       case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
> +               return axp20x_battery_set_max_voltage(axp20x_batt, val->intval);
> +
> +       case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
> +               return axp20x_set_constant_charge_current(axp20x_batt,
> +                                                         val->intval);
> +
> +       default:
> +               return -EINVAL;
> +       }
> +}
> +
> +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_CONSTANT_CHARGE_CURRENT,
> +       POWER_SUPPLY_PROP_CONSTANT_CHARGE_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_CONSTANT_CHARGE_CURRENT;
> +}
> +
> +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_batt_ps *axp20x_batt;
> +       struct power_supply_config psy_cfg = {};
> +       struct power_supply_battery_info info;
> +
> +       if (!of_device_is_available(pdev->dev.of_node))
> +               return -ENODEV;
> +
> +       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 = dev_get_regmap(pdev->dev.parent, NULL);
> +       platform_set_drvdata(pdev, axp20x_batt);
> +
> +       psy_cfg.drv_data = axp20x_batt;
> +       psy_cfg.of_node = pdev->dev.of_node;
> +
> +       axp20x_batt->axp_id = (uintptr_t)of_device_get_match_data(&pdev->dev);
> +
> +       axp20x_batt->batt = devm_power_supply_register(&pdev->dev,
> +                                                      &axp20x_batt_ps_desc,
> +                                                      &psy_cfg);
> +       if (IS_ERR(axp20x_batt->batt)) {
> +               dev_err(&pdev->dev, "failed to register power supply: %ld\n",
> +                       PTR_ERR(axp20x_batt->batt));
> +               return PTR_ERR(axp20x_batt->batt);
> +       }
> +
> +       if (!power_supply_get_battery_info(axp20x_batt->batt, &info)) {
> +               int vmin = info.voltage_min_design_uv;
> +               int ccc = info.constant_charge_current_ua;
> +
> +               if (vmin > 0 && axp20x_set_voltage_min_design(axp20x_batt,
> +                                                             vmin))
> +                       dev_err(&pdev->dev,
> +                               "couldn't set voltage_min_design\n");
> +
> +               if (ccc > 0 && axp20x_set_constant_charge_current(axp20x_batt,
> +                                                                 ccc))
> +                       dev_err(&pdev->dev,
> +                               "couldn't set constant charge current\n");
> +       }
> +
> +       return 0;
> +}
> +
> +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
>