I2C MUXes described by the i2c-gpio-mux sometimes need a significant
amount of time to switch from a bus to another. When a new bus is
selected, the first I2C transfer can fail if it occurs too early. There
is no way to describe this transition delay that has to be waited before
starting the first I2C transfer.

Add a 'settle-time-us' property that indicates the delay to be
respected before doing the first i2c transfer.

Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>
---
 Documentation/devicetree/bindings/i2c/i2c-mux-gpio.yaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.yaml
index f34cc7ad5a00..4a93d1f78f93 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.yaml
+++ b/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.yaml
@@ -57,6 +57,9 @@ properties:
       last value used.
     $ref: /schemas/types.yaml#/definitions/uint32
 
+  settle-time-us:
+    description: Delay to wait before doing any transfer when a new bus gets selected.
+
 allOf:
   - $ref: i2c-mux.yaml
 
-- 
2.45.0

$subject should be "mux-gpio" instead of just "gpio". It could be mixed
up with the i2c-gpio controller driver otherwise.

2024-06-17 at 14:08, Bastien Curutchet wrote:
> I2C MUXes described by the i2c-gpio-mux sometimes need a significant
> amount of time to switch from a bus to another. When a new bus is
> selected, the first I2C transfer can fail if it occurs too early. There
> is no way to describe this transition delay that has to be waited before
> starting the first I2C transfer.
> 
> Add a 'settle-time-us' property that indicates the delay to be
> respected before doing the first i2c transfer.
> 
> Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>

Acked-by: Peter Rosin <peda@axentia.se>

Cheers,
Peter

Hi,

On Mon, Jun 17, 2024 at 02:08:16PM GMT, Bastien Curutchet wrote:
> I2C MUXes described by the i2c-gpio-mux sometimes need a significant
> amount of time to switch from a bus to another. When a new bus is
> selected, the first I2C transfer can fail if it occurs too early. There
> is no way to describe this transition delay that has to be waited before
> starting the first I2C transfer.
> 
> Add a 'settle-time-us' property that indicates the delay to be
> respected before doing the first i2c transfer.
> 
> Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>

Reviewed-by: Andi Shyti <andi.shyti@kernel.org> 

Andi

On 17/06/2024 14:08, Bastien Curutchet wrote:
> I2C MUXes described by the i2c-gpio-mux sometimes need a significant
> amount of time to switch from a bus to another. When a new bus is
> selected, the first I2C transfer can fail if it occurs too early. There
> is no way to describe this transition delay that has to be waited before
> starting the first I2C transfer.
> 
> Add a 'settle-time-us' property that indicates the delay to be
> respected before doing the first i2c transfer.
> 
> Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>


Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof