diff mbox series

[v5,1/3] dt-bindings: i2c-gpio: Add properties for dealing with write-only SDA/SCL w/o pullup

Message ID 8eb4fb92-ea53-fb4e-4cdd-daed4ad96806@gmail.com
State New
Headers show
Series i2c: gpio: support write-only sda | expand

Commit Message

Heiner Kallweit Jan. 18, 2023, 9:51 p.m. UTC
There are slave devices that understand I2C but have read-only SDA and
SCL. Examples are FD650 7-segment LED controller and its derivatives.
Typical board designs don't even have a pull-up for both pins.
Therefore add properties for not using open-drain. For write-only SCL
we have a property already, add one for write-only SDA.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v4:
- add no-pullup properties
v5:
- add checking mutually-exclusive properties to schema
---
 .../devicetree/bindings/i2c/i2c-gpio.yaml     | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)

Comments

Rob Herring (Arm) Jan. 23, 2023, 9:08 p.m. UTC | #1
On Wed, 18 Jan 2023 22:51:58 +0100, Heiner Kallweit wrote:
> There are slave devices that understand I2C but have read-only SDA and
> SCL. Examples are FD650 7-segment LED controller and its derivatives.
> Typical board designs don't even have a pull-up for both pins.
> Therefore add properties for not using open-drain. For write-only SCL
> we have a property already, add one for write-only SDA.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> v4:
> - add no-pullup properties
> v5:
> - add checking mutually-exclusive properties to schema
> ---
>  .../devicetree/bindings/i2c/i2c-gpio.yaml     | 26 +++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 

Reviewed-by: Rob Herring <robh@kernel.org>
Wolfram Sang Jan. 23, 2023, 10:20 p.m. UTC | #2
On Wed, Jan 18, 2023 at 10:51:58PM +0100, Heiner Kallweit wrote:
> There are slave devices that understand I2C but have read-only SDA and
> SCL. Examples are FD650 7-segment LED controller and its derivatives.
> Typical board designs don't even have a pull-up for both pins.
> Therefore add properties for not using open-drain. For write-only SCL
> we have a property already, add one for write-only SDA.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

Applied to for-next, thanks!
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml b/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml
index e0d76d5eb..afd4925c2 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml
+++ b/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml
@@ -33,6 +33,10 @@  properties:
       open drain.
     maxItems: 1
 
+  i2c-gpio,sda-output-only:
+    description: sda as output only
+    type: boolean
+
   i2c-gpio,scl-output-only:
     description: scl as output only
     type: boolean
@@ -63,6 +67,28 @@  properties:
       GPIO line used for SCL into open drain mode, and that something is not
       the GPIO chip. It is essentially an inconsistency flag.
 
+  i2c-gpio,sda-has-no-pullup:
+    type: boolean
+    description: sda is used in a non-compliant way and has no pull-up.
+      Therefore disable open-drain. This property is mutually-exclusive
+      with i2c-gpio,sda-open-drain.
+
+  i2c-gpio,scl-has-no-pullup:
+    type: boolean
+    description: scl is used in a non-compliant way and has no pull-up.
+      Therefore disable open-drain. This property is mutually-exclusive
+      with i2c-gpio,scl-open-drain.
+
+dependencies:
+  i2c-gpio,sda-has-no-pullup:
+    not:
+      required:
+        - i2c-gpio,sda-open-drain
+  i2c-gpio,scl-has-no-pullup:
+    not:
+      required:
+        - i2c-gpio,scl-open-drain
+
 required:
   - compatible
   - sda-gpios