[PATCH v3 0/4] hwmon: (sht21) Add devicetree support

[PATCH v3 0/4] hwmon: (sht21) Add devicetree support

[Kurt Borja]

Hi all,

The sht21 driver actually supports all i2c sht2x chips so add support
for those names and additionally add DT support.

Tested for sht20 and verified against the datasheet for sht25.

Thanks!

Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
Changes in v3:
- Add MODULE_DEVICE_TABLE() (I forgot, sorry for the noise!)
- Link to v2: https://lore.kernel.org/r/20250907-sht2x-v2-0-1c7dc90abf8e@gmail.com

Changes in v2:
- Add a documentation cleanup patch
- Add entry for each chip instead of sht2x placeholder
- Update Kconfig too
- Link to v1: https://lore.kernel.org/r/20250907-sht2x-v1-0-fd56843b1b43@gmail.com

---
Kurt Borja (4):
      hwmon: (sht21) Documentation cleanup
      hwmon: (sht21) Add support for SHT20, SHT25 chips
      hwmon: (sht21) Add devicetree support
      dt-bindings: trivial-devices: Add sht2x sensors

 .../devicetree/bindings/trivial-devices.yaml       |  3 +++
 Documentation/hwmon/sht21.rst                      | 26 +++++++++++++---------
 drivers/hwmon/Kconfig                              |  4 ++--
 drivers/hwmon/sht21.c                              | 15 ++++++++++++-
 4 files changed, 34 insertions(+), 14 deletions(-)
---
base-commit: b236920731dd90c3fba8c227aa0c4dee5351a639
change-id: 20250907-sht2x-9b96125a0cf5
-- 
 ~ Kurt

[PATCH v3 1/4] hwmon: (sht21) Documentation cleanup

[Kurt Borja]

Drop extra empty lines and organize sysfs entries in a table.

Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
 Documentation/hwmon/sht21.rst | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/Documentation/hwmon/sht21.rst b/Documentation/hwmon/sht21.rst
index 1bccc8e8aac8d3532ec17dcdbc6a172102877085..9f66cd51b45dc4b89ce757d2209445478de046cd 100644
--- a/Documentation/hwmon/sht21.rst
+++ b/Documentation/hwmon/sht21.rst
@@ -13,8 +13,6 @@ Supported chips:
 
     https://www.sensirion.com/file/datasheet_sht21
 
-
-
   * Sensirion SHT25
 
     Prefix: 'sht25'
@@ -25,8 +23,6 @@ Supported chips:
 
     https://www.sensirion.com/file/datasheet_sht25
 
-
-
 Author:
 
   Urs Fleisch <urs.fleisch@sensirion.com>
@@ -47,13 +43,11 @@ in the board setup code.
 sysfs-Interface
 ---------------
 
-temp1_input
-	- temperature input
-
-humidity1_input
-	- humidity input
-eic
-	- Electronic Identification Code
+=================== ============================================================
+temp1_input         Temperature input
+humidity1_input     Humidity input
+eic                 Electronic Identification Code
+=================== ============================================================
 
 Notes
 -----

-- 
2.51.0

[PATCH v3 2/4] hwmon: (sht21) Add support for SHT20, SHT25 chips

[Kurt Borja]

All sht2x chips share the same communication protocol so add support for
them.

Cc: stable@vger.kernel.org
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
 Documentation/hwmon/sht21.rst | 10 ++++++++++
 drivers/hwmon/Kconfig         |  4 ++--
 drivers/hwmon/sht21.c         |  2 ++
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/Documentation/hwmon/sht21.rst b/Documentation/hwmon/sht21.rst
index 9f66cd51b45dc4b89ce757d2209445478de046cd..d20e8a460ba6c7c8452bcdce68a1fce963413640 100644
--- a/Documentation/hwmon/sht21.rst
+++ b/Documentation/hwmon/sht21.rst
@@ -3,6 +3,16 @@ Kernel driver sht21
 
 Supported chips:
 
+  * Sensirion SHT20
+
+    Prefix: 'sht20'
+
+    Addresses scanned: none
+
+    Datasheet: Publicly available at the Sensirion website
+
+    https://www.sensirion.com/file/datasheet_sht20
+
   * Sensirion SHT21
 
     Prefix: 'sht21'
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 9d28fcf7cd2a6f9e2f54694a717bd85ff4047b46..90dc8051418689e7a92293df15ce35cd822c77ff 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1930,8 +1930,8 @@ config SENSORS_SHT21
 	tristate "Sensiron humidity and temperature sensors. SHT21 and compat."
 	depends on I2C
 	help
-	  If you say yes here you get support for the Sensiron SHT21, SHT25
-	  humidity and temperature sensors.
+	  If you say yes here you get support for the Sensiron SHT20, SHT21,
+	  SHT25 humidity and temperature sensors.
 
 	  This driver can also be built as a module. If so, the module
 	  will be called sht21.
diff --git a/drivers/hwmon/sht21.c b/drivers/hwmon/sht21.c
index 97327313529b467ed89d8f6b06c2d78efd54efbf..97d71e3361e9d7f0512880149ba6479601b2fc0c 100644
--- a/drivers/hwmon/sht21.c
+++ b/drivers/hwmon/sht21.c
@@ -275,7 +275,9 @@ static int sht21_probe(struct i2c_client *client)
 
 /* Device ID table */
 static const struct i2c_device_id sht21_id[] = {
+	{ "sht20" },
 	{ "sht21" },
+	{ "sht25" },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, sht21_id);

-- 
2.51.0

Re: [PATCH v3 2/4] hwmon: (sht21) Add support for SHT20, SHT25 chips

[Guenter Roeck]

On 9/7/25 18:33, Kurt Borja wrote:
> All sht2x chips share the same communication protocol so add support for
> them.
> 
> Cc: stable@vger.kernel.org

FWIW, I am going to drop this when applying. I don't add stable tags
for patches which are not bug fixes. Anyone who wants such patches
backported can request that separately after the patch is upstream.

Guenter

[PATCH v3 3/4] hwmon: (sht21) Add devicetree support

[Kurt Borja]

Add DT support for sht2x chips.

Cc: stable@vger.kernel.org
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
 drivers/hwmon/sht21.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/sht21.c b/drivers/hwmon/sht21.c
index 97d71e3361e9d7f0512880149ba6479601b2fc0c..627d35070a420ab9e51634bdc5cf5e3de3853326 100644
--- a/drivers/hwmon/sht21.c
+++ b/drivers/hwmon/sht21.c
@@ -282,8 +282,19 @@ static const struct i2c_device_id sht21_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, sht21_id);
 
+static const struct of_device_id sht21_of_match[] = {
+	{ .compatible = "sensirion,sht20" },
+	{ .compatible = "sensirion,sht21" },
+	{ .compatible = "sensirion,sht25" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sht21_of_match);
+
 static struct i2c_driver sht21_driver = {
-	.driver.name = "sht21",
+	.driver = {
+		.name = "sht21",
+		.of_match_table = sht21_of_match,
+	},
 	.probe       = sht21_probe,
 	.id_table    = sht21_id,
 };

-- 
2.51.0

Re: [PATCH v3 3/4] hwmon: (sht21) Add devicetree support

[Krzysztof Kozlowski]

On 08/09/2025 03:33, Kurt Borja wrote:
> Add DT support for sht2x chips.
> 
> Cc: stable@vger.kernel.org

Describe the bug, otherwise not a stable backport.


Best regards,
Krzysztof

[PATCH v3 4/4] dt-bindings: trivial-devices: Add sht2x sensors

[Kurt Borja]

Add sensirion,sht2x trivial sensors.

Cc: stable@vger.kernel.org
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
 Documentation/devicetree/bindings/trivial-devices.yaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
index f3dd18681aa6f81255141bdda6daf8e45369a2c2..952244a7105591a0095b1ae57da7cb7345bdfc61 100644
--- a/Documentation/devicetree/bindings/trivial-devices.yaml
+++ b/Documentation/devicetree/bindings/trivial-devices.yaml
@@ -362,6 +362,9 @@ properties:
             # Sensirion low power multi-pixel gas sensor with I2C interface
           - sensirion,sgpc3
             # Sensirion temperature & humidity sensor with I2C interface
+          - sensirion,sht20
+          - sensirion,sht21
+          - sensirion,sht25
           - sensirion,sht4x
             # Sensortek 3 axis accelerometer
           - sensortek,stk8312

-- 
2.51.0

Re: [PATCH v3 4/4] dt-bindings: trivial-devices: Add sht2x sensors

[Krzysztof Kozlowski]

On 08/09/2025 03:33, Kurt Borja wrote:
> Add sensirion,sht2x trivial sensors.
> 
> Cc: stable@vger.kernel.org

No, drop. No bug to fix here.

Please organize the patch documenting compatible (DT bindings) before
their user.
See also:
https://elixir.bootlin.com/linux/v6.14-rc6/source/Documentation/devicetree/bindings/submitting-patches.rst#L46
> 


Best regards,
Krzysztof

Re: [PATCH v3 4/4] dt-bindings: trivial-devices: Add sht2x sensors

[Kurt Borja]

Hi Krzysztof,

On Mon Sep 8, 2025 at 2:02 AM -05, Krzysztof Kozlowski wrote:
> On 08/09/2025 03:33, Kurt Borja wrote:
>> Add sensirion,sht2x trivial sensors.
>> 
>> Cc: stable@vger.kernel.org
>
> No, drop. No bug to fix here.

I included it because stable is fine with device IDs [1]. Is this
avoided with dt-bindings related stuff?

>
> Please organize the patch documenting compatible (DT bindings) before
> their user.
> See also:
> https://elixir.bootlin.com/linux/v6.14-rc6/source/Documentation/devicetree/bindings/submitting-patches.rst#L46

I will reorder.

Thanks for the review!

>> 
>
>
> Best regards,
> Krzysztof

[1] https://elixir.bootlin.com/linux/v6.17-rc4/source/Documentation/process/stable-kernel-rules.rst#L15

-- 
 ~ Kurt

Re: [PATCH v3 4/4] dt-bindings: trivial-devices: Add sht2x sensors

[Krzysztof Kozlowski]

On 08/09/2025 13:28, Kurt Borja wrote:
> Hi Krzysztof,
> 
> On Mon Sep 8, 2025 at 2:02 AM -05, Krzysztof Kozlowski wrote:
>> On 08/09/2025 03:33, Kurt Borja wrote:
>>> Add sensirion,sht2x trivial sensors.
>>>
>>> Cc: stable@vger.kernel.org
>>
>> No, drop. No bug to fix here.
> 
> I included it because stable is fine with device IDs [1]. Is this
> avoided with dt-bindings related stuff?

You do not add quirks or new IDs. You add something completely new -
support for OF. That's a feature in this driver.

Best regards,
Krzysztof