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@xxxxxxxxx>
---
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 },
{ },
