[PATCH] hwmon: (lm75) Add MAX31725/6 support

[Guenter Roeck]

On Tue, Sep 11, 2018 at 01:25:58PM -0700, Kun Yi wrote:
> MAX31725/MAX31726 are local temperature sensors with +/- 0.5 degree
> Celsius accuracy and 16-bit (0.00390625 degrees Celsius) resolution.
> They have a register mapping and encoding compatible with the lm75
> series drivers. Address scan and extended temperature range are
> not supported by this patch.
> 
> Tested on real hardware and verified temperature readings are correct.
> 
> Signed-off-by: Kun Yi <kunyi at google.com>

Applied to hwmon-next.

Thanks,
Guenter

> ---
>  Documentation/hwmon/lm75 |  6 +++---
>  drivers/hwmon/lm75.c     | 18 ++++++++++++++++--
>  2 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/hwmon/lm75 b/Documentation/hwmon/lm75
> index ac95edfcd907..2f1120f88c16 100644
> --- a/Documentation/hwmon/lm75
> +++ b/Documentation/hwmon/lm75
> @@ -17,8 +17,8 @@ Supported chips:
>      Addresses scanned: none
>      Datasheet: Publicly available at the Maxim website
>                 http://www.maximintegrated.com/
> -  * Maxim MAX6625, MAX6626
> -    Prefixes: 'max6625', 'max6626'
> +  * Maxim MAX6625, MAX6626, MAX31725, MAX31726
> +    Prefixes: 'max6625', 'max6626', 'max31725', 'max31726'
>      Addresses scanned: none
>      Datasheet: Publicly available at the Maxim website
>                 http://www.maxim-ic.com/
> @@ -86,7 +86,7 @@ The LM75 is essentially an industry standard; there may be other
>  LM75 clones not listed here, with or without various enhancements,
>  that are supported. The clones are not detected by the driver, unless
>  they reproduce the exact register tricks of the original LM75, and must
> -therefore be instantiated explicitly. Higher resolution up to 12-bit
> +therefore be instantiated explicitly. Higher resolution up to 16-bit
>  is supported by this driver, other specific enhancements are not.
>  
>  The LM77 is not supported, contrary to what we pretended for a long time.
> diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
> index 49f4b33a5685..e6e5a1080f09 100644
> --- a/drivers/hwmon/lm75.c
> +++ b/drivers/hwmon/lm75.c
> @@ -47,6 +47,7 @@ enum lm75_type {		/* keep sorted in alphabetical order */
>  	lm75b,
>  	max6625,
>  	max6626,
> +	max31725,
>  	mcp980x,
>  	stds75,
>  	tcn75,
> @@ -64,7 +65,6 @@ enum lm75_type {		/* keep sorted in alphabetical order */
>  static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
>  					0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
>  
> -
>  /* The LM75 registers */
>  #define LM75_REG_TEMP		0x00
>  #define LM75_REG_CONF		0x01
> @@ -76,7 +76,7 @@ struct lm75_data {
>  	struct i2c_client	*client;
>  	struct regmap		*regmap;
>  	u8			orig_conf;
> -	u8			resolution;	/* In bits, between 9 and 12 */
> +	u8			resolution;	/* In bits, between 9 and 16 */
>  	u8			resolution_limits;
>  	unsigned int		sample_time;	/* In ms */
>  };
> @@ -339,6 +339,10 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  		data->resolution_limits = 9;
>  		data->sample_time = MSEC_PER_SEC / 4;
>  		break;
> +	case max31725:
> +		data->resolution = 16;
> +		data->sample_time = MSEC_PER_SEC / 8;
> +		break;
>  	case tcn75:
>  		data->resolution = 9;
>  		data->sample_time = MSEC_PER_SEC / 8;
> @@ -415,6 +419,8 @@ static const struct i2c_device_id lm75_ids[] = {
>  	{ "lm75b", lm75b, },
>  	{ "max6625", max6625, },
>  	{ "max6626", max6626, },
> +	{ "max31725", max31725, },
> +	{ "max31726", max31725, },
>  	{ "mcp980x", mcp980x, },
>  	{ "stds75", stds75, },
>  	{ "tcn75", tcn75, },
> @@ -471,6 +477,14 @@ static const struct of_device_id lm75_of_match[] = {
>  		.compatible = "maxim,max6626",
>  		.data = (void *)max6626
>  	},
> +	{
> +		.compatible = "maxim,max31725",
> +		.data = (void *)max31725
> +	},
> +	{
> +		.compatible = "maxim,max31726",
> +		.data = (void *)max31725
> +	},
>  	{
>  		.compatible = "maxim,mcp980x",
>  		.data = (void *)mcp980x
> -- 
> 2.19.0.rc2.392.g5ba43deb5a-goog
>