[PATCH v1 1/2] dt-bindings: add TI TMP125 temperature sensor binding

[PATCH v1 1/2] dt-bindings: add TI TMP125 temperature sensor binding

[Christian Lamparter]

From the Datasheet:

"The TMP125 is an SPI-compatible temperature sensor available
in the tiny SOT23-6 package. Requiring no external components,
the TMP125 is capable of measuring temperatures within
2 degree C of accuracy over a temperature range of −25 °C to
+85 °C and 2.5 °C of accuracy over −40°C to +125°C."

This chip can be supported by the current hwmon's lm70 module.
(lm70 already has support for the TMP124 and friends)

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
---
 Documentation/devicetree/bindings/trivial-devices.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
index 091792ba993e..09b98bf97c8d 100644
--- a/Documentation/devicetree/bindings/trivial-devices.yaml
+++ b/Documentation/devicetree/bindings/trivial-devices.yaml
@@ -337,6 +337,7 @@ properties:
             # Thermometer with SPI interface
           - ti,tmp121
           - ti,tmp122
+          - ti,tmp125
             # Digital Temperature Sensor
           - ti,tmp275
             # TI DC-DC converter on PMBus
-- 
2.35.1

[PATCH v1 2/2] hwmon: (lm70) Add ti,tmp125 support

[Christian Lamparter]

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 signed two's
complement format. Bits 4 to 0 are mirrors of Bit 5 and
therefore ignored.

This was tested on a Aerohive HiveAP-350.

Bonus: lm70 supports TMP122/TMP124 as well. So, I
added them to the Kconfig module description as well.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
---

Datasheet: (Link)
<https://www.ti.com/lit/ds/symlink/tmp125.pdf>

I'm not sure if it's "Ok" to add the TMP125 to this lm70.
It seems like it, especially since the TMP124 and friends
are supported by this driver.
---
 drivers/hwmon/Kconfig |  4 ++--
 drivers/hwmon/lm70.c  | 15 +++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 8df25f1079ba..5cdf38004fae 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
+	  and 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..4202e4e03584 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 +88,11 @@ 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 followed by
+	 * 9 temperature bits (D13..D5) of 2's complement data,
+	 * discard LSB 5 bits (same as D5), resolution 0.25 degress celsius.
 	 */
 	switch (p_lm70->chip) {
 	case LM70_CHIP_LM70:
@@ -102,6 +108,10 @@ 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 +145,10 @@ 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 +198,7 @@ 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 },
 	{ },
-- 
2.35.1

Re: [PATCH v1 2/2] hwmon: (lm70) Add ti,tmp125 support

[Guenter Roeck]

On 2/17/22 08:47, 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 signed two's
> complement format. Bits 4 to 0 are mirrors of Bit 5 and
> therefore ignored.
> 
> This was tested on a Aerohive HiveAP-350.
> 
> Bonus: lm70 supports TMP122/TMP124 as well. So, I
> added them to the Kconfig module description as well.
> 
> Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
> ---
> 
> Datasheet: (Link)
> <https://www.ti.com/lit/ds/symlink/tmp125.pdf>
> 
> I'm not sure if it's "Ok" to add the TMP125 to this lm70.
> It seems like it, especially since the TMP124 and friends
> are supported by this driver.

Better than a separate driver just for a few lines of code.

> ---
>   drivers/hwmon/Kconfig |  4 ++--
>   drivers/hwmon/lm70.c  | 15 +++++++++++++++

Please also add the chip to Documentation/hwmon/lm70.rst.

>   2 files changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 8df25f1079ba..5cdf38004fae 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
> +	  and 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..4202e4e03584 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 +88,11 @@ 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 followed by
> +	 * 9 temperature bits (D13..D5) of 2's complement data,
> +	 * discard LSB 5 bits (same as D5), resolution 0.25 degress celsius.

degrees

>   	 */
>   	switch (p_lm70->chip) {
>   	case LM70_CHIP_LM70:
> @@ -102,6 +108,10 @@ 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 +145,10 @@ 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 +198,7 @@ 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 },
>   	{ },