Re: [PATCH v2 09/11] power: supply: max17042: initial support for Maxim MAX77759
From: Peter Griffin
Date: Fri Feb 27 2026 - 12:06:58 EST
On Fri, 27 Feb 2026 at 07:15, André Draszik <andre.draszik@xxxxxxxxxx> wrote:
>
> The Maxim MAX77759 is a companion PMIC intended for use in mobile
> phones and tablets. It is used on Google Pixel 6 and 6 Pro (oriole and
> raven). Amongst others, it contains a fuel gauge that is similar to the
> ones supported by this driver.
>
> The fuel gauge can measure battery charge and discharge current,
> battery voltage, battery temperature, and the Type C connector's
> temperature.
>
> The MAX77759 incorporates the Maxim ModelGauge m5 algorithm. It, as
> well as previous generations like m3 on max17047/max17050, requires
> the host to save/restore some register values across power cycles to
> maintain full accuracy. Extending the driver for such support is out of
> scope in this initial commit.
>
> Signed-off-by: André Draszik <andre.draszik@xxxxxxxxxx>
>
> ---
Reviewed-by: Peter Griffin <peter.griffin@xxxxxxxxxx>
> v2: fix typo MAX77759_T_convert -> MAX77759_Tconvert
> ---
> drivers/power/supply/max17042_battery.c | 59 ++++++++++++++++++++++++++++++---
> include/linux/power/max17042_battery.h | 24 ++++++++++++--
> 2 files changed, 77 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/power/supply/max17042_battery.c b/drivers/power/supply/max17042_battery.c
> index 823533ea5a17..44626abdab34 100644
> --- a/drivers/power/supply/max17042_battery.c
> +++ b/drivers/power/supply/max17042_battery.c
> @@ -654,7 +654,8 @@ static void max17042_write_config_regs(struct max17042_chip *chip)
> regmap_write(map, MAX17042_RelaxCFG, config->relax_cfg);
> if (chip->chip_type == MAXIM_DEVICE_TYPE_MAX17047 ||
> chip->chip_type == MAXIM_DEVICE_TYPE_MAX17050 ||
> - chip->chip_type == MAXIM_DEVICE_TYPE_MAX17055)
> + chip->chip_type == MAXIM_DEVICE_TYPE_MAX17055 ||
> + chip->chip_type == MAXIM_DEVICE_TYPE_MAX77759)
> regmap_write(map, MAX17047_FullSOCThr,
> config->full_soc_thresh);
> }
> @@ -791,7 +792,8 @@ static inline void max17042_override_por_values(struct max17042_chip *chip)
>
> if ((chip->chip_type == MAXIM_DEVICE_TYPE_MAX17042) ||
> (chip->chip_type == MAXIM_DEVICE_TYPE_MAX17047) ||
> - (chip->chip_type == MAXIM_DEVICE_TYPE_MAX17050)) {
> + (chip->chip_type == MAXIM_DEVICE_TYPE_MAX17050) ||
> + (chip->chip_type == MAXIM_DEVICE_TYPE_MAX77759)) {
> max17042_override_por(map, MAX17042_IAvg_empty, config->iavg_empty);
> max17042_override_por(map, MAX17042_TempNom, config->temp_nom);
> max17042_override_por(map, MAX17042_TempLim, config->temp_lim);
> @@ -800,7 +802,8 @@ static inline void max17042_override_por_values(struct max17042_chip *chip)
>
> if ((chip->chip_type == MAXIM_DEVICE_TYPE_MAX17047) ||
> (chip->chip_type == MAXIM_DEVICE_TYPE_MAX17050) ||
> - (chip->chip_type == MAXIM_DEVICE_TYPE_MAX17055)) {
> + (chip->chip_type == MAXIM_DEVICE_TYPE_MAX17055) ||
> + (chip->chip_type == MAXIM_DEVICE_TYPE_MAX77759)) {
> max17042_override_por(map, MAX17047_V_empty, config->vempty);
> }
> }
> @@ -1023,6 +1026,45 @@ static const struct regmap_config max17042_regmap_config = {
> .val_format_endian = REGMAP_ENDIAN_NATIVE,
> };
>
> +static const struct regmap_range max77759_fg_registers[] = {
> + regmap_reg_range(MAX17042_STATUS, MAX77759_MixAtFull),
> + regmap_reg_range(MAX17042_VFSOC0Enable, MAX17042_VFSOC0Enable),
> + regmap_reg_range(MAX17042_MLOCKReg1, MAX17042_MLOCKReg2),
> + regmap_reg_range(MAX17042_MODELChrTbl, MAX17055_TimerH),
> + regmap_reg_range(MAX77759_IIn, MAX77759_IIn),
> + regmap_reg_range(MAX17055_AtQResidual, MAX17055_AtAvCap),
> + regmap_reg_range(MAX17042_OCVInternal, MAX17042_OCVInternal),
> + regmap_reg_range(MAX17042_VFSOC, MAX17042_VFSOC),
> +};
> +
> +static const struct regmap_range max77759_fg_ro_registers[] = {
> + regmap_reg_range(MAX17042_FSTAT, MAX17042_FSTAT),
> + regmap_reg_range(MAX17042_OCVInternal, MAX17042_OCVInternal),
> + regmap_reg_range(MAX17042_VFSOC, MAX17042_VFSOC),
> +};
> +
> +static const struct regmap_access_table max77759_fg_write_table = {
> + .yes_ranges = max77759_fg_registers,
> + .n_yes_ranges = ARRAY_SIZE(max77759_fg_registers),
> + .no_ranges = max77759_fg_ro_registers,
> + .n_no_ranges = ARRAY_SIZE(max77759_fg_ro_registers),
> +};
> +
> +static const struct regmap_access_table max77759_fg_rd_table = {
> + .yes_ranges = max77759_fg_registers,
> + .n_yes_ranges = ARRAY_SIZE(max77759_fg_registers),
> +};
> +
> +static const struct regmap_config max77759_fg_regmap_cfg = {
> + .reg_bits = 8,
> + .val_bits = 16,
> + .max_register = 0xff,
> + .wr_table = &max77759_fg_write_table,
> + .rd_table = &max77759_fg_rd_table,
> + .val_format_endian = REGMAP_ENDIAN_NATIVE,
> + .cache_type = REGCACHE_NONE,
> +};
> +
> static const struct power_supply_desc max17042_psy_desc = {
> .name = "max170xx_battery",
> .type = POWER_SUPPLY_TYPE_BATTERY,
> @@ -1049,6 +1091,7 @@ static int max17042_probe(struct i2c_client *client, struct device *dev, int irq
> {
> struct i2c_adapter *adapter = client->adapter;
> const struct power_supply_desc *max17042_desc = &max17042_psy_desc;
> + const struct regmap_config *regmap_config;
> struct power_supply_config psy_cfg = {};
> struct max17042_chip *chip;
> int ret;
> @@ -1064,7 +1107,12 @@ static int max17042_probe(struct i2c_client *client, struct device *dev, int irq
>
> chip->dev = dev;
> chip->chip_type = chip_type;
> - chip->regmap = devm_regmap_init_i2c(client, &max17042_regmap_config);
> +
> + if (chip->chip_type == MAXIM_DEVICE_TYPE_MAX77759)
> + regmap_config = &max77759_fg_regmap_cfg;
> + else
> + regmap_config = &max17042_regmap_config;
> + chip->regmap = devm_regmap_init_i2c(client, regmap_config);
> if (IS_ERR(chip->regmap))
> return dev_err_probe(dev, PTR_ERR(chip->regmap),
> "Failed to initialize regmap\n");
> @@ -1245,6 +1293,8 @@ static const struct of_device_id max17042_dt_match[] __used = {
> .data = (void *) MAXIM_DEVICE_TYPE_MAX17055 },
> { .compatible = "maxim,max77705-battery",
> .data = (void *) MAXIM_DEVICE_TYPE_MAX17047 },
> + { .compatible = "maxim,max77759-fg",
> + .data = (void *) MAXIM_DEVICE_TYPE_MAX77759 },
> { .compatible = "maxim,max77849-battery",
> .data = (void *) MAXIM_DEVICE_TYPE_MAX17047 },
> { },
> @@ -1257,6 +1307,7 @@ static const struct i2c_device_id max17042_id[] = {
> { "max17047", MAXIM_DEVICE_TYPE_MAX17047 },
> { "max17050", MAXIM_DEVICE_TYPE_MAX17050 },
> { "max17055", MAXIM_DEVICE_TYPE_MAX17055 },
> + { "max77759-fg", MAXIM_DEVICE_TYPE_MAX77759 },
> { "max77849-battery", MAXIM_DEVICE_TYPE_MAX17047 },
> { }
> };
> diff --git a/include/linux/power/max17042_battery.h b/include/linux/power/max17042_battery.h
> index c417abd2ab70..05097f08ea36 100644
> --- a/include/linux/power/max17042_battery.h
> +++ b/include/linux/power/max17042_battery.h
> @@ -105,7 +105,7 @@ enum max17042_register {
>
> MAX17042_OCV = 0xEE,
>
> - MAX17042_OCVInternal = 0xFB, /* MAX17055 VFOCV */
> + MAX17042_OCVInternal = 0xFB, /* MAX17055/77759 VFOCV */
>
> MAX17042_VFSOC = 0xFF,
> };
> @@ -156,7 +156,7 @@ enum max17055_register {
> MAX17055_AtAvCap = 0xDF,
> };
>
> -/* Registers specific to max17047/50/55 */
> +/* Registers specific to max17047/50/55/77759 */
> enum max17047_register {
> MAX17047_QRTbl00 = 0x12,
> MAX17047_FullSOCThr = 0x13,
> @@ -167,12 +167,32 @@ enum max17047_register {
> MAX17047_QRTbl30 = 0x42,
> };
>
> +enum max77759_register {
> + MAX77759_AvgTA0 = 0x26,
> + MAX77759_AtTTF = 0x33,
> + MAX77759_Tconvert = 0x34,
> + MAX77759_AvgCurrent0 = 0x3B,
> + MAX77759_THMHOT = 0x40,
> + MAX77759_CTESample = 0x41,
> + MAX77759_ISys = 0x43,
> + MAX77759_AvgVCell0 = 0x44,
> + MAX77759_RlxSOC = 0x47,
> + MAX77759_AvgISys = 0x4B,
> + MAX77759_QH0 = 0x4C,
> + MAX77759_MixAtFull = 0x4F,
> + MAX77759_VSys = 0xB1,
> + MAX77759_TAlrtTh2 = 0xB2,
> + MAX77759_VByp = 0xB3,
> + MAX77759_IIn = 0xD0,
> +};
> +
> enum max170xx_chip_type {
> MAXIM_DEVICE_TYPE_UNKNOWN = 0,
> MAXIM_DEVICE_TYPE_MAX17042,
> MAXIM_DEVICE_TYPE_MAX17047,
> MAXIM_DEVICE_TYPE_MAX17050,
> MAXIM_DEVICE_TYPE_MAX17055,
> + MAXIM_DEVICE_TYPE_MAX77759,
>
> MAXIM_DEVICE_TYPE_NUM
> };
>
> --
> 2.53.0.473.g4a7958ca14-goog
>