diff mbox series

[v2,1/4] power: supply: add support for max77759 fuel gauge

Message ID 20250102-b4-gs101_max77759_fg-v2-1-87959abeb7ff@uclouvain.be (mailing list archive)
State New
Headers show
Series Google Pixel 6 (oriole): max77759 fuel gauge enablement and driver support | expand

Commit Message

Thomas Antoine via B4 Relay Jan. 2, 2025, 11:15 a.m. UTC
From: Thomas Antoine <t.antoine@uclouvain.be>

The interface of the Maxim max77759 fuel gauge has a lot of common with the
Maxim max1720x. The major difference is the lack of non-volatile memory
slave address. No slave is available at address 0xb of the i2c bus, which
is coherent with the following driver from google: line 5836 disables
non-volatile memory for m5 gauge.

Link: https://android.googlesource.com/kernel/google-modules/bms/+/1a68c36bef474573cc8629cc1d121eb6a81ab68c/max1720x_battery.c

Other differences include the lack of V_BATT register to read the battery
level and a difference in the way to identify the chip (the same register
is used but not the same mask).

Add support for the max77759 by allowing to use the non-volatile
memory or not based on the chip. Also add the V_CELL regsister as a
fallback to read voltage value in the case where read of V_BATT fails.

The cast is necessary to avoid an overflow when the value of the register
is above 54975 (equivalent to a voltage around 4.29 V).

The regmap of the max77759 will lead the read to fail for V_BATT and to
correctly use V_CELL instead. This regmap was proposed by André Draszik in

Link: https://lore.kernel.org/all/d1bade77b5281c1de6b2ddcb4dbbd033e455a116.camel@linaro.org/

Signed-off-by: Thomas Antoine <t.antoine@uclouvain.be>
---
 drivers/power/supply/max1720x_battery.c | 189 +++++++++++++++++++++++++++-----
 1 file changed, 164 insertions(+), 25 deletions(-)

Comments

Dimitri Fedrau Jan. 6, 2025, 3:16 p.m. UTC | #1
Hi Thomas,

Am Thu, Jan 02, 2025 at 12:15:03PM +0100 schrieb Thomas Antoine via B4 Relay:
> From: Thomas Antoine <t.antoine@uclouvain.be>
> 
> The interface of the Maxim max77759 fuel gauge has a lot of common with the
> Maxim max1720x. The major difference is the lack of non-volatile memory
> slave address. No slave is available at address 0xb of the i2c bus, which
> is coherent with the following driver from google: line 5836 disables
> non-volatile memory for m5 gauge.
> 
> Link: https://android.googlesource.com/kernel/google-modules/bms/+/1a68c36bef474573cc8629cc1d121eb6a81ab68c/max1720x_battery.c
> 
> Other differences include the lack of V_BATT register to read the battery
> level and a difference in the way to identify the chip (the same register
> is used but not the same mask).
> 
> Add support for the max77759 by allowing to use the non-volatile
> memory or not based on the chip. Also add the V_CELL regsister as a
> fallback to read voltage value in the case where read of V_BATT fails.
> 
> The cast is necessary to avoid an overflow when the value of the register
> is above 54975 (equivalent to a voltage around 4.29 V).
> 
> The regmap of the max77759 will lead the read to fail for V_BATT and to
> correctly use V_CELL instead. This regmap was proposed by André Draszik in
> 
> Link: https://lore.kernel.org/all/d1bade77b5281c1de6b2ddcb4dbbd033e455a116.camel@linaro.org/
> 
> Signed-off-by: Thomas Antoine <t.antoine@uclouvain.be>
> ---
>  drivers/power/supply/max1720x_battery.c | 189 +++++++++++++++++++++++++++-----
>  1 file changed, 164 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/power/supply/max1720x_battery.c b/drivers/power/supply/max1720x_battery.c
> index 33105419e2427bb37963bda9948b647c239f8faa..a41976679eded44fbd13120ad756a626d2867919 100644
> --- a/drivers/power/supply/max1720x_battery.c
> +++ b/drivers/power/supply/max1720x_battery.c
> @@ -27,6 +27,7 @@
>  #define MAX172XX_REPCAP			0x05	/* Average capacity */
>  #define MAX172XX_REPSOC			0x06	/* Percentage of charge */
>  #define MAX172XX_TEMP			0x08	/* Temperature */
> +#define MAX172XX_VCELL			0x09	/* Lowest cell voltage */
>  #define MAX172XX_CURRENT		0x0A	/* Actual current */
>  #define MAX172XX_AVG_CURRENT		0x0B	/* Average current */
>  #define MAX172XX_TTE			0x11	/* Time to empty */
> @@ -39,6 +40,8 @@
>  #define MAX172XX_DEV_NAME_TYPE_MASK	GENMASK(3, 0)
>  #define MAX172XX_DEV_NAME_TYPE_MAX17201	BIT(0)
>  #define MAX172XX_DEV_NAME_TYPE_MAX17205	(BIT(0) | BIT(2))
> +#define MAX77759_DEV_NAME_TYPE_MASK	GENMASK(15, 9)
> +#define MAX77759_DEV_NAME_TYPE_MAX77759	0x31
>  #define MAX172XX_QR_TABLE10		0x22
>  #define MAX172XX_BATT			0xDA	/* Battery voltage */
>  #define MAX172XX_ATAVCAP		0xDF
> @@ -46,12 +49,20 @@
>  static const char *const max1720x_manufacturer = "Maxim Integrated";
>  static const char *const max17201_model = "MAX17201";
>  static const char *const max17205_model = "MAX17205";
> +static const char *const max77759_model = "MAX77759";
> +
> +enum chip_id {
> +	MAX1720X_ID,
> +	MAX77759_ID,
> +};
>  
>  struct max1720x_device_info {
>  	struct regmap *regmap;
>  	struct regmap *regmap_nv;
>  	struct i2c_client *ancillary;
>  	int rsense;
> +	int has_nvmem;

Switch to bool and why is needed twice ? Here and in chip_data. Better
keep it in chip_data.

> +	enum chip_id id;
>  };
>  
>  /*
> @@ -254,6 +265,67 @@ static const enum power_supply_property max1720x_battery_props[] = {
>  	POWER_SUPPLY_PROP_MANUFACTURER,
>  };
>  
> +/*
> + * Registers 0x80 up to 0xaf which contain the model for the fuel gauge
> + * algorithm (stored in nvmem for the max1720x) are locked. They can
> + * be unlocked by writing 0x59 to 0x62 and 0xc4 to 0x63. They should be
> + * enabled in the regmap if the driver is extended to manage the model.
> + */
> +static const struct regmap_range max77759_registers[] = {
> +	regmap_reg_range(0x00, 0x4f),
> +	regmap_reg_range(0xb0, 0xbf),
> +	regmap_reg_range(0xd0, 0xd0),
> +	regmap_reg_range(0xdc, 0xdf),
> +	regmap_reg_range(0xfb, 0xfb),
> +	regmap_reg_range(0xff, 0xff),
> +};
> +
> +static const struct regmap_range max77759_ro_registers[] = {
> +	regmap_reg_range(0x3d, 0x3d),
> +	regmap_reg_range(0xfb, 0xfb),
> +	regmap_reg_range(0xff, 0xff),
> +};
> +
> +static const struct regmap_access_table max77759_write_table = {
> +	.yes_ranges = max77759_registers,
> +	.n_yes_ranges = ARRAY_SIZE(max77759_registers),
> +	.no_ranges = max77759_ro_registers,
> +	.n_no_ranges = ARRAY_SIZE(max77759_ro_registers),
> +};
> +
> +static const struct regmap_access_table max77759_rd_table = {
> +	.yes_ranges = max77759_registers,
> +	.n_yes_ranges = ARRAY_SIZE(max77759_registers),
> +};
> +
> +static const struct regmap_config max77759_regmap_cfg = {
> +	.reg_bits = 8,
> +	.val_bits = 16,
> +	.max_register = 0xff,
> +	.wr_table = &max77759_write_table,
> +	.rd_table = &max77759_rd_table,
> +	.val_format_endian = REGMAP_ENDIAN_LITTLE,
> +	.cache_type = REGCACHE_NONE,
> +};
> +
> +struct chip_data {
> +	u8 has_nvmem;
> +	const struct regmap_config *regmap_cfg;
> +	enum chip_id id;
> +};
> +
> +static const struct chip_data max1720x_data  = {
> +	.has_nvmem = 1,
> +	.regmap_cfg = &max1720x_regmap_cfg,
> +	.id = MAX1720X_ID,
> +};
> +
> +static const struct chip_data max77759_data = {
> +	.has_nvmem = 0,
> +	.regmap_cfg = &max77759_regmap_cfg,
> +	.id = MAX77759_ID,
> +};
> +
>  /* Convert regs value to power_supply units */
>  
>  static int max172xx_time_to_ps(unsigned int reg)
> @@ -271,6 +343,14 @@ static int max172xx_voltage_to_ps(unsigned int reg)
>  	return reg * 1250;	/* in uV */
>  }
>  
> +// Use 64 bits because computation on 32 bits leads to an overflow
> +static int max172xx_cell_voltage_to_ps(unsigned int reg)
> +{
> +	u64 val = reg;
> +
> +	return val * 78125 / 1000;	/* in uV */

You could avoid the overflow with:
	return val * 625 / 8;	/* in uV */
> +}
> +
>  static int max172xx_capacity_to_ps(unsigned int reg)
>  {
>  	return reg * 500;	/* in uAh */
> @@ -303,6 +383,33 @@ static int max172xx_current_to_voltage(unsigned int reg)
>  	return val * 156252;
>  }
>  
> +static int max1720x_devname_to_model(unsigned int reg_val,
> +					union power_supply_propval *val,
> +					struct max1720x_device_info *info)

nit: Align with open parenthesis

> +{
> +	switch (info->id) {
> +	case MAX1720X_ID:
> +		reg_val = FIELD_GET(MAX172XX_DEV_NAME_TYPE_MASK, reg_val);
> +		if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17201)
> +			val->strval = max17201_model;
> +		else if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17205)
> +			val->strval = max17205_model;
> +		else
> +			return -ENODEV;
> +		break;
> +	case MAX77759_ID:
> +		reg_val = FIELD_GET(MAX77759_DEV_NAME_TYPE_MASK, reg_val);
> +		if (reg_val == MAX77759_DEV_NAME_TYPE_MAX77759)
> +			val->strval = max77759_model;
> +		else
> +			return -ENODEV;
> +		break;
> +	default:
> +		return -ENODEV;
> +	}
> +	return 0;
> +}
> +
>  static int max1720x_battery_get_property(struct power_supply *psy,
>  					 enum power_supply_property psp,
>  					 union power_supply_propval *val)
> @@ -332,7 +439,12 @@ static int max1720x_battery_get_property(struct power_supply *psy,
>  		break;
>  	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
>  		ret = regmap_read(info->regmap, MAX172XX_BATT, &reg_val);
> -		val->intval = max172xx_voltage_to_ps(reg_val);
> +		if (!ret)
> +			val->intval = max172xx_voltage_to_ps(reg_val);
> +		else {
> +			ret = regmap_read(info->regmap, MAX172XX_VCELL, &reg_val);
> +			val->intval = max172xx_cell_voltage_to_ps(reg_val);
> +		}

Would be better to read the right register, since we know which device
we are. You could differentiate like in max1720x_devname_to_model.

>  		break;
>  	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
>  		ret = regmap_read(info->regmap, MAX172XX_DESIGN_CAP, &reg_val);
> @@ -364,13 +476,8 @@ static int max1720x_battery_get_property(struct power_supply *psy,
>  		break;
>  	case POWER_SUPPLY_PROP_MODEL_NAME:
>  		ret = regmap_read(info->regmap, MAX172XX_DEV_NAME, &reg_val);
> -		reg_val = FIELD_GET(MAX172XX_DEV_NAME_TYPE_MASK, reg_val);
> -		if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17201)
> -			val->strval = max17201_model;
> -		else if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17205)
> -			val->strval = max17205_model;
> -		else
> -			return -ENODEV;
> +		if (!ret)
> +			ret = max1720x_devname_to_model(reg_val, val, info);
>  		break;
>  	case POWER_SUPPLY_PROP_MANUFACTURER:
>  		val->strval = max1720x_manufacturer;
> @@ -416,7 +523,6 @@ static int max1720x_probe_nvmem(struct i2c_client *client,
>  		.priv = info,
>  	};
>  	struct nvmem_device *nvmem;
> -	unsigned int val;
>  	int ret;
>  
>  	info->ancillary = i2c_new_ancillary_device(client, "nvmem", 0xb);
> @@ -438,18 +544,6 @@ static int max1720x_probe_nvmem(struct i2c_client *client,
>  		return PTR_ERR(info->regmap_nv);
>  	}
>  
> -	ret = regmap_read(info->regmap_nv, MAX1720X_NRSENSE, &val);
> -	if (ret < 0) {
> -		dev_err(dev, "Failed to read sense resistor value\n");
> -		return ret;
> -	}
> -
> -	info->rsense = val;
> -	if (!info->rsense) {
> -		dev_warn(dev, "RSense not calibrated, set 10 mOhms!\n");
> -		info->rsense = 1000; /* in regs in 10^-5 */
> -	}
> -
>  	nvmem = devm_nvmem_register(dev, &nvmem_config);
>  	if (IS_ERR(nvmem)) {
>  		dev_err(dev, "Could not register nvmem!");
> @@ -459,6 +553,36 @@ static int max1720x_probe_nvmem(struct i2c_client *client,
>  	return 0;
>  }
>  
> +static int max1720x_get_rsense(struct device *dev,
> +					 struct max1720x_device_info *info)

nit: Align with open parenthesis.

> +{
> +	unsigned int val;
> +	int ret;
> +
> +	if (info->has_nvmem) {
> +		ret = regmap_read(info->regmap_nv, MAX1720X_NRSENSE, &val);
> +		if (ret < 0) {
> +			dev_err(dev, "Failed to read RSense from nvmem\n");
> +			return ret;
> +		}
> +
> +		info->rsense = val;
> +		if (!info->rsense) {
> +			dev_warn(dev, "RSense not calibrated, set 10 mOhms!\n");
> +			info->rsense = 1000; /* in regs in 10^-5 */
> +		}
> +	} else {
> +		ret = of_property_read_u32(dev->of_node,
> +					"shunt-resistor-micro-ohms", &val);

nit: Align with open parenthesis.

> +		if (ret) {
> +			dev_err(dev, "Failed to read RSense from devicetree\n");
> +			return ret;
> +		}
> +		info->rsense = val/10;
> +	}
> +	return 0;
> +}
> 
[...]

Best regards,
Dimitri Fedrau
André Draszik Jan. 7, 2025, 11 a.m. UTC | #2
Hi Thomas,

Thanks for your patch!

On Thu, 2025-01-02 at 12:15 +0100, Thomas Antoine via B4 Relay wrote:
> From: Thomas Antoine <t.antoine@uclouvain.be>
> 
> The interface of the Maxim max77759 fuel gauge has a lot of common with the
> Maxim max1720x. The major difference is the lack of non-volatile memory
> slave address. No slave is available at address 0xb of the i2c bus, which
> is coherent with the following driver from google: line 5836 disables
> non-volatile memory for m5 gauge.
> 
> Link: https://android.googlesource.com/kernel/google-modules/bms/+/1a68c36bef474573cc8629cc1d121eb6a81ab68c/max1720x_battery.c
> 
> Other differences include the lack of V_BATT register to read the battery
> level and a difference in the way to identify the chip (the same register
> is used but not the same mask).

It also seems the reported POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN is
quite a bit off - on my Pixel 6, it reports ca. 1131mAh, but the downstream
stack reports a more reasonable 4524mAh. Interestingly, this is an exact
multiple of four.

POWER_SUPPLY_PROP_CHARGE_FULL is off in a similar way, and I suspect that
related properties like charge_avg, time_to_empty, time_to_full are
reported incorrectly as well.

[...]

> @@ -483,14 +608,27 @@ static int max1720x_probe(struct i2c_client *client)
>  	psy_cfg.drv_data = info;
>  	psy_cfg.fwnode = dev_fwnode(dev);
>  	i2c_set_clientdata(client, info);
> -	info->regmap = devm_regmap_init_i2c(client, &max1720x_regmap_cfg);
> +
> +	data = device_get_match_data(dev);
> +	if (!data)
> +		return dev_err_probe(dev, ret, "Failed to get chip data\n");
                                          ^^^
This should be -EINVAL.


Cheers,
Andre'
Christophe JAILLET Jan. 7, 2025, 6:10 p.m. UTC | #3
Le 02/01/2025 à 12:15, Thomas Antoine via B4 Relay a écrit :
> From: Thomas Antoine <t.antoine@uclouvain.be>
> 
> The interface of the Maxim max77759 fuel gauge has a lot of common with the
> Maxim max1720x. The major difference is the lack of non-volatile memory
> slave address. No slave is available at address 0xb of the i2c bus, which
> is coherent with the following driver from google: line 5836 disables
> non-volatile memory for m5 gauge.

Hi,

...

> +	ret = max1720x_get_rsense(dev, info);
>   	if (ret)
> -		return dev_err_probe(dev, ret, "Failed to probe nvmem\n");
> +		return dev_err_probe(dev, ret, "Failed to get RSense");

Missing ending \n.

>   
>   	bat = devm_power_supply_register(dev, &max1720x_bat_desc, &psy_cfg);
>   	if (IS_ERR(bat))

...

CJ
Peter Griffin Jan. 8, 2025, 9:49 a.m. UTC | #4
Hi Thomas,

On Thu, 2 Jan 2025 at 11:16, Thomas Antoine via B4 Relay
<devnull+t.antoine.uclouvain.be@kernel.org> wrote:
>
> From: Thomas Antoine <t.antoine@uclouvain.be>
>
> The interface of the Maxim max77759 fuel gauge has a lot of common with the
> Maxim max1720x. The major difference is the lack of non-volatile memory
> slave address. No slave is available at address 0xb of the i2c bus, which
> is coherent with the following driver from google: line 5836 disables
> non-volatile memory for m5 gauge.
>
> Link: https://android.googlesource.com/kernel/google-modules/bms/+/1a68c36bef474573cc8629cc1d121eb6a81ab68c/max1720x_battery.c
>
> Other differences include the lack of V_BATT register to read the battery
> level and a difference in the way to identify the chip (the same register
> is used but not the same mask).
>
> Add support for the max77759 by allowing to use the non-volatile
> memory or not based on the chip. Also add the V_CELL regsister as a
> fallback to read voltage value in the case where read of V_BATT fails.
>
> The cast is necessary to avoid an overflow when the value of the register
> is above 54975 (equivalent to a voltage around 4.29 V).
>
> The regmap of the max77759 will lead the read to fail for V_BATT and to
> correctly use V_CELL instead. This regmap was proposed by André Draszik in
>
> Link: https://lore.kernel.org/all/d1bade77b5281c1de6b2ddcb4dbbd033e455a116.camel@linaro.org/

Firstly thanks for working on this :) Fuel gauge is a great addition
to the Pixel 6 upstream support.

It would be good if you can document what you consider "working" with
this series applied. I think it's fine for support to come
incrementally (say feature additions to the driver to support x,y,z).
But anything that is now reported in sysfs with this series applied
should be accurate (or alternatively not exposed for MAX77759 variant
if it's not accurate and it's unclear from checking the downstream
driver how to fix it).

Thanks,

Peter
diff mbox series

Patch

diff --git a/drivers/power/supply/max1720x_battery.c b/drivers/power/supply/max1720x_battery.c
index 33105419e2427bb37963bda9948b647c239f8faa..a41976679eded44fbd13120ad756a626d2867919 100644
--- a/drivers/power/supply/max1720x_battery.c
+++ b/drivers/power/supply/max1720x_battery.c
@@ -27,6 +27,7 @@ 
 #define MAX172XX_REPCAP			0x05	/* Average capacity */
 #define MAX172XX_REPSOC			0x06	/* Percentage of charge */
 #define MAX172XX_TEMP			0x08	/* Temperature */
+#define MAX172XX_VCELL			0x09	/* Lowest cell voltage */
 #define MAX172XX_CURRENT		0x0A	/* Actual current */
 #define MAX172XX_AVG_CURRENT		0x0B	/* Average current */
 #define MAX172XX_TTE			0x11	/* Time to empty */
@@ -39,6 +40,8 @@ 
 #define MAX172XX_DEV_NAME_TYPE_MASK	GENMASK(3, 0)
 #define MAX172XX_DEV_NAME_TYPE_MAX17201	BIT(0)
 #define MAX172XX_DEV_NAME_TYPE_MAX17205	(BIT(0) | BIT(2))
+#define MAX77759_DEV_NAME_TYPE_MASK	GENMASK(15, 9)
+#define MAX77759_DEV_NAME_TYPE_MAX77759	0x31
 #define MAX172XX_QR_TABLE10		0x22
 #define MAX172XX_BATT			0xDA	/* Battery voltage */
 #define MAX172XX_ATAVCAP		0xDF
@@ -46,12 +49,20 @@ 
 static const char *const max1720x_manufacturer = "Maxim Integrated";
 static const char *const max17201_model = "MAX17201";
 static const char *const max17205_model = "MAX17205";
+static const char *const max77759_model = "MAX77759";
+
+enum chip_id {
+	MAX1720X_ID,
+	MAX77759_ID,
+};
 
 struct max1720x_device_info {
 	struct regmap *regmap;
 	struct regmap *regmap_nv;
 	struct i2c_client *ancillary;
 	int rsense;
+	int has_nvmem;
+	enum chip_id id;
 };
 
 /*
@@ -254,6 +265,67 @@  static const enum power_supply_property max1720x_battery_props[] = {
 	POWER_SUPPLY_PROP_MANUFACTURER,
 };
 
+/*
+ * Registers 0x80 up to 0xaf which contain the model for the fuel gauge
+ * algorithm (stored in nvmem for the max1720x) are locked. They can
+ * be unlocked by writing 0x59 to 0x62 and 0xc4 to 0x63. They should be
+ * enabled in the regmap if the driver is extended to manage the model.
+ */
+static const struct regmap_range max77759_registers[] = {
+	regmap_reg_range(0x00, 0x4f),
+	regmap_reg_range(0xb0, 0xbf),
+	regmap_reg_range(0xd0, 0xd0),
+	regmap_reg_range(0xdc, 0xdf),
+	regmap_reg_range(0xfb, 0xfb),
+	regmap_reg_range(0xff, 0xff),
+};
+
+static const struct regmap_range max77759_ro_registers[] = {
+	regmap_reg_range(0x3d, 0x3d),
+	regmap_reg_range(0xfb, 0xfb),
+	regmap_reg_range(0xff, 0xff),
+};
+
+static const struct regmap_access_table max77759_write_table = {
+	.yes_ranges = max77759_registers,
+	.n_yes_ranges = ARRAY_SIZE(max77759_registers),
+	.no_ranges = max77759_ro_registers,
+	.n_no_ranges = ARRAY_SIZE(max77759_ro_registers),
+};
+
+static const struct regmap_access_table max77759_rd_table = {
+	.yes_ranges = max77759_registers,
+	.n_yes_ranges = ARRAY_SIZE(max77759_registers),
+};
+
+static const struct regmap_config max77759_regmap_cfg = {
+	.reg_bits = 8,
+	.val_bits = 16,
+	.max_register = 0xff,
+	.wr_table = &max77759_write_table,
+	.rd_table = &max77759_rd_table,
+	.val_format_endian = REGMAP_ENDIAN_LITTLE,
+	.cache_type = REGCACHE_NONE,
+};
+
+struct chip_data {
+	u8 has_nvmem;
+	const struct regmap_config *regmap_cfg;
+	enum chip_id id;
+};
+
+static const struct chip_data max1720x_data  = {
+	.has_nvmem = 1,
+	.regmap_cfg = &max1720x_regmap_cfg,
+	.id = MAX1720X_ID,
+};
+
+static const struct chip_data max77759_data = {
+	.has_nvmem = 0,
+	.regmap_cfg = &max77759_regmap_cfg,
+	.id = MAX77759_ID,
+};
+
 /* Convert regs value to power_supply units */
 
 static int max172xx_time_to_ps(unsigned int reg)
@@ -271,6 +343,14 @@  static int max172xx_voltage_to_ps(unsigned int reg)
 	return reg * 1250;	/* in uV */
 }
 
+// Use 64 bits because computation on 32 bits leads to an overflow
+static int max172xx_cell_voltage_to_ps(unsigned int reg)
+{
+	u64 val = reg;
+
+	return val * 78125 / 1000;	/* in uV */
+}
+
 static int max172xx_capacity_to_ps(unsigned int reg)
 {
 	return reg * 500;	/* in uAh */
@@ -303,6 +383,33 @@  static int max172xx_current_to_voltage(unsigned int reg)
 	return val * 156252;
 }
 
+static int max1720x_devname_to_model(unsigned int reg_val,
+					union power_supply_propval *val,
+					struct max1720x_device_info *info)
+{
+	switch (info->id) {
+	case MAX1720X_ID:
+		reg_val = FIELD_GET(MAX172XX_DEV_NAME_TYPE_MASK, reg_val);
+		if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17201)
+			val->strval = max17201_model;
+		else if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17205)
+			val->strval = max17205_model;
+		else
+			return -ENODEV;
+		break;
+	case MAX77759_ID:
+		reg_val = FIELD_GET(MAX77759_DEV_NAME_TYPE_MASK, reg_val);
+		if (reg_val == MAX77759_DEV_NAME_TYPE_MAX77759)
+			val->strval = max77759_model;
+		else
+			return -ENODEV;
+		break;
+	default:
+		return -ENODEV;
+	}
+	return 0;
+}
+
 static int max1720x_battery_get_property(struct power_supply *psy,
 					 enum power_supply_property psp,
 					 union power_supply_propval *val)
@@ -332,7 +439,12 @@  static int max1720x_battery_get_property(struct power_supply *psy,
 		break;
 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 		ret = regmap_read(info->regmap, MAX172XX_BATT, &reg_val);
-		val->intval = max172xx_voltage_to_ps(reg_val);
+		if (!ret)
+			val->intval = max172xx_voltage_to_ps(reg_val);
+		else {
+			ret = regmap_read(info->regmap, MAX172XX_VCELL, &reg_val);
+			val->intval = max172xx_cell_voltage_to_ps(reg_val);
+		}
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 		ret = regmap_read(info->regmap, MAX172XX_DESIGN_CAP, &reg_val);
@@ -364,13 +476,8 @@  static int max1720x_battery_get_property(struct power_supply *psy,
 		break;
 	case POWER_SUPPLY_PROP_MODEL_NAME:
 		ret = regmap_read(info->regmap, MAX172XX_DEV_NAME, &reg_val);
-		reg_val = FIELD_GET(MAX172XX_DEV_NAME_TYPE_MASK, reg_val);
-		if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17201)
-			val->strval = max17201_model;
-		else if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17205)
-			val->strval = max17205_model;
-		else
-			return -ENODEV;
+		if (!ret)
+			ret = max1720x_devname_to_model(reg_val, val, info);
 		break;
 	case POWER_SUPPLY_PROP_MANUFACTURER:
 		val->strval = max1720x_manufacturer;
@@ -416,7 +523,6 @@  static int max1720x_probe_nvmem(struct i2c_client *client,
 		.priv = info,
 	};
 	struct nvmem_device *nvmem;
-	unsigned int val;
 	int ret;
 
 	info->ancillary = i2c_new_ancillary_device(client, "nvmem", 0xb);
@@ -438,18 +544,6 @@  static int max1720x_probe_nvmem(struct i2c_client *client,
 		return PTR_ERR(info->regmap_nv);
 	}
 
-	ret = regmap_read(info->regmap_nv, MAX1720X_NRSENSE, &val);
-	if (ret < 0) {
-		dev_err(dev, "Failed to read sense resistor value\n");
-		return ret;
-	}
-
-	info->rsense = val;
-	if (!info->rsense) {
-		dev_warn(dev, "RSense not calibrated, set 10 mOhms!\n");
-		info->rsense = 1000; /* in regs in 10^-5 */
-	}
-
 	nvmem = devm_nvmem_register(dev, &nvmem_config);
 	if (IS_ERR(nvmem)) {
 		dev_err(dev, "Could not register nvmem!");
@@ -459,6 +553,36 @@  static int max1720x_probe_nvmem(struct i2c_client *client,
 	return 0;
 }
 
+static int max1720x_get_rsense(struct device *dev,
+					 struct max1720x_device_info *info)
+{
+	unsigned int val;
+	int ret;
+
+	if (info->has_nvmem) {
+		ret = regmap_read(info->regmap_nv, MAX1720X_NRSENSE, &val);
+		if (ret < 0) {
+			dev_err(dev, "Failed to read RSense from nvmem\n");
+			return ret;
+		}
+
+		info->rsense = val;
+		if (!info->rsense) {
+			dev_warn(dev, "RSense not calibrated, set 10 mOhms!\n");
+			info->rsense = 1000; /* in regs in 10^-5 */
+		}
+	} else {
+		ret = of_property_read_u32(dev->of_node,
+					"shunt-resistor-micro-ohms", &val);
+		if (ret) {
+			dev_err(dev, "Failed to read RSense from devicetree\n");
+			return ret;
+		}
+		info->rsense = val/10;
+	}
+	return 0;
+}
+
 static const struct power_supply_desc max1720x_bat_desc = {
 	.name = "max1720x",
 	.no_thermal = true,
@@ -474,6 +598,7 @@  static int max1720x_probe(struct i2c_client *client)
 	struct device *dev = &client->dev;
 	struct max1720x_device_info *info;
 	struct power_supply *bat;
+	const struct chip_data *data;
 	int ret;
 
 	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
@@ -483,14 +608,27 @@  static int max1720x_probe(struct i2c_client *client)
 	psy_cfg.drv_data = info;
 	psy_cfg.fwnode = dev_fwnode(dev);
 	i2c_set_clientdata(client, info);
-	info->regmap = devm_regmap_init_i2c(client, &max1720x_regmap_cfg);
+
+	data = device_get_match_data(dev);
+	if (!data)
+		return dev_err_probe(dev, ret, "Failed to get chip data\n");
+
+	info->has_nvmem = data->has_nvmem;
+	info->id = data->id;
+	info->regmap = devm_regmap_init_i2c(client, data->regmap_cfg);
 	if (IS_ERR(info->regmap))
 		return dev_err_probe(dev, PTR_ERR(info->regmap),
 				     "regmap initialization failed\n");
 
-	ret = max1720x_probe_nvmem(client, info);
+	if (data->has_nvmem) {
+		ret = max1720x_probe_nvmem(client, info);
+		if (ret)
+			return dev_err_probe(dev, ret, "Failed to probe nvmem\n");
+	}
+
+	ret = max1720x_get_rsense(dev, info);
 	if (ret)
-		return dev_err_probe(dev, ret, "Failed to probe nvmem\n");
+		return dev_err_probe(dev, ret, "Failed to get RSense");
 
 	bat = devm_power_supply_register(dev, &max1720x_bat_desc, &psy_cfg);
 	if (IS_ERR(bat))
@@ -501,7 +639,8 @@  static int max1720x_probe(struct i2c_client *client)
 }
 
 static const struct of_device_id max1720x_of_match[] = {
-	{ .compatible = "maxim,max17201" },
+	{ .compatible = "maxim,max17201", .data = (void *) &max1720x_data },
+	{ .compatible = "maxim,max77759-fg", .data = (void *) &max77759_data },
 	{}
 };
 MODULE_DEVICE_TABLE(of, max1720x_of_match);