Re: [PATCH v2 2/2] hwmon: (lm70) Add ti,tmp125 support

[Guenter Roeck <linux@roeck-us.net>]

On Fri, Feb 18, 2022 at 10:06:43AM +0100, Christian Lamparter wrote:
> The TMP125 is a 2 degree Celsius accurate Digital
> Temperature Sensor with a SPI interface.
> 
> The temperature register is a 16-bit, read-only register.
> The MSB (Bit 15) is a leading zero and never set. Bits 14
> to 5 are the 1+9 temperature data bits in a two's
> complement format. Bits 4 to 0 are useless copies of
> Bit 5 value and therefore ignored.
> 
> This was tested on a Aerohive HiveAP-350.
> 
> Bonus: lm70 supports TMP122/TMP124 as well.
> I added them to the Kconfig module description.
> 
> Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

Applied to hwmon-next.

Thanks,
Guenter

> ---
> v1 -> v2: - spelling fixes + nicer (IMHO) texts (Roeck)
> 	  - added entry to Documentation/hwmon/lm70.rst (Roeck)
> ---
>  Documentation/hwmon/lm70.rst |  7 +++++++
>  drivers/hwmon/Kconfig        |  4 ++--
>  drivers/hwmon/lm70.c         | 16 ++++++++++++++++
>  3 files changed, 25 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/hwmon/lm70.rst b/Documentation/hwmon/lm70.rst
> index 6ddc5b67ccb5..11303a7e16a8 100644
> --- a/Documentation/hwmon/lm70.rst
> +++ b/Documentation/hwmon/lm70.rst
> @@ -15,6 +15,10 @@ Supported chips:
>  
>      Information: https://www.ti.com/product/tmp122
>  
> +  * Texas Instruments TMP125
> +
> +    Information: https://www.ti.com/product/tmp125
> +
>    * National Semiconductor LM71
>  
>      Datasheet: https://www.ti.com/product/LM71
> @@ -53,6 +57,9 @@ The LM74 and TMP121/TMP122/TMP123/TMP124 are very similar; main difference is
>  
>  The TMP122/TMP124 also feature configurable temperature thresholds.
>  
> +The TMP125 is less accurate and provides 10-bit temperature data
> +with 0.25 degrees Celsius resolution.
> +
>  The LM71 is also very similar; main difference is 14-bit temperature
>  data (0.03125 degrees celsius resolution).
>  
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 8df25f1079ba..94a47e70533f 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1208,8 +1208,8 @@ config SENSORS_LM70
>  	depends on SPI_MASTER
>  	help
>  	  If you say yes here you get support for the National Semiconductor
> -	  LM70, LM71, LM74 and Texas Instruments TMP121/TMP123 digital tempera-
> -	  ture sensor chips.
> +	  LM70, LM71, LM74 and Texas Instruments TMP121/TMP123, TMP122/TMP124,
> +	  TMP125 digital temperature sensor chips.
>  
>  	  This driver can also be built as a module. If so, the module
>  	  will be called lm70.
> diff --git a/drivers/hwmon/lm70.c b/drivers/hwmon/lm70.c
> index d2a60de5b8de..c20a749fc7f2 100644
> --- a/drivers/hwmon/lm70.c
> +++ b/drivers/hwmon/lm70.c
> @@ -34,6 +34,7 @@
>  #define LM70_CHIP_LM71		2	/* NS LM71 */
>  #define LM70_CHIP_LM74		3	/* NS LM74 */
>  #define LM70_CHIP_TMP122	4	/* TI TMP122/TMP124 */
> +#define LM70_CHIP_TMP125	5	/* TI TMP125 */
>  
>  struct lm70 {
>  	struct spi_device *spi;
> @@ -87,6 +88,12 @@ static ssize_t temp1_input_show(struct device *dev,
>  	 * LM71:
>  	 * 14 bits of 2's complement data, discard LSB 2 bits,
>  	 * resolution 0.0312 degrees celsius.
> +	 *
> +	 * TMP125:
> +	 * MSB/D15 is a leading zero. D14 is the sign-bit. This is
> +	 * followed by 9 temperature bits (D13..D5) in 2's complement
> +	 * data format with a resolution of 0.25 degrees celsius per unit.
> +	 * LSB 5 bits (D4..D0) share the same value as D5 and get discarded.
>  	 */
>  	switch (p_lm70->chip) {
>  	case LM70_CHIP_LM70:
> @@ -102,6 +109,10 @@ static ssize_t temp1_input_show(struct device *dev,
>  	case LM70_CHIP_LM71:
>  		val = ((int)raw / 4) * 3125 / 100;
>  		break;
> +
> +	case LM70_CHIP_TMP125:
> +		val = (sign_extend32(raw, 14) / 32) * 250;
> +		break;
>  	}
>  
>  	status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
> @@ -135,6 +146,10 @@ static const struct of_device_id lm70_of_ids[] = {
>  		.compatible = "ti,tmp122",
>  		.data = (void *) LM70_CHIP_TMP122,
>  	},
> +	{
> +		.compatible = "ti,tmp125",
> +		.data = (void *) LM70_CHIP_TMP125,
> +	},
>  	{
>  		.compatible = "ti,lm71",
>  		.data = (void *) LM70_CHIP_LM71,
> @@ -184,6 +199,7 @@ static const struct spi_device_id lm70_ids[] = {
>  	{ "lm70",   LM70_CHIP_LM70 },
>  	{ "tmp121", LM70_CHIP_TMP121 },
>  	{ "tmp122", LM70_CHIP_TMP122 },
> +	{ "tmp125", LM70_CHIP_TMP125 },
>  	{ "lm71",   LM70_CHIP_LM71 },
>  	{ "lm74",   LM70_CHIP_LM74 },
>  	{ },