Re: [PATCH v1 4/4] power: max17040: get thermal data from adc if available

[Sebastian Reichel]

Hi,

On Wed, Mar 08, 2023 at 10:44:19AM +0200, Svyatoslav Ryhel wrote:
> Since fuel gauge does not support thermal monitoring,
> some vendors may couple this fuel gauge with thermal/adc
> sensor to monitor battery cell exact temperature.
> 
> Add this feature by adding optional iio thermal channel.
> 
> Signed-off-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx>
> ---
>  drivers/power/supply/max17040_battery.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/power/supply/max17040_battery.c b/drivers/power/supply/max17040_battery.c
> index 6dfce7b1309e..8c743c26dc6e 100644
> --- a/drivers/power/supply/max17040_battery.c
> +++ b/drivers/power/supply/max17040_battery.c
> @@ -18,6 +18,7 @@
>  #include <linux/of_device.h>
>  #include <linux/regmap.h>
>  #include <linux/slab.h>
> +#include <linux/iio/consumer.h>
>  
>  #define MAX17040_VCELL	0x02
>  #define MAX17040_SOC	0x04
> @@ -143,6 +144,7 @@ struct max17040_chip {
>  	struct power_supply		*battery;
>  	struct power_supply_battery_info	*batt_info;
>  	struct chip_data		data;
> +	struct iio_channel		*channel_temp;
>  
>  	/* battery capacity */
>  	int soc;
> @@ -416,6 +418,11 @@ static int max17040_get_property(struct power_supply *psy,
>  	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
>  		val->intval = chip->batt_info->charge_full_design_uah;
>  		break;
> +	case POWER_SUPPLY_PROP_TEMP:
> +		iio_read_channel_raw(chip->channel_temp,
> +				     &val->intval);
> +		val->intval *= 10;

return iio_read_channel_processed_scale(chip->channel_temp, &val->intval, 10);

> +		break;
>  	case POWER_SUPPLY_PROP_TEMP_MIN:
>  		if (chip->batt_info->temp_min == INT_MIN)
>  			return -ENODATA;
> @@ -452,6 +459,7 @@ static enum power_supply_property max17040_battery_props[] = {
>  	POWER_SUPPLY_PROP_HEALTH,
>  	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
>  	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
> +	POWER_SUPPLY_PROP_TEMP,

You should only expose this, if chip->channel_temp is not NULL. Use
devm_kmemdup() to copy the array into a private copy in chip and
modify it on the fly.
    
>  	POWER_SUPPLY_PROP_TEMP_MIN,
>  	POWER_SUPPLY_PROP_TEMP_MAX,
>  };
> @@ -560,9 +568,24 @@ static int max17040_probe(struct i2c_client *client)
>  		}
>  	}
>  
> +	if (of_property_read_bool(client->dev.of_node, "io-channels")) {

device_property_present()

> +		chip->channel_temp = iio_channel_get(&client->dev, "temp");

devm_iio_channel_get()

> +		if (IS_ERR(chip->channel_temp))
> +			return dev_err_probe(&client->dev, PTR_ERR(chip->channel_temp),
> +					     "failed to get temp\n");
> +	};

Also this must be acquired before registering the power-supply device.

-- Sebastian

> +
>  	return 0;
>  }
>  
> +static void max17040_remove(struct i2c_client *client)
> +{
> +	struct max17040_chip *chip = i2c_get_clientdata(client);
> +
> +	if (chip->channel_temp)
> +		iio_channel_release(chip->channel_temp);
> +}
> +
>  #ifdef CONFIG_PM_SLEEP
>  
>  static int max17040_suspend(struct device *dev)
> @@ -642,6 +665,7 @@ static struct i2c_driver max17040_i2c_driver = {
>  		.pm	= MAX17040_PM_OPS,
>  	},
>  	.probe_new	= max17040_probe,
> +	.remove		= max17040_remove,
>  	.id_table	= max17040_id,
>  };
>  module_i2c_driver(max17040_i2c_driver);
> -- 
> 2.37.2
>

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