Re: [PATCH v7 3/5] ARM: dts: stm32: Add I2C1 support for STM32F429 SoC

[M'boumba Cedric Madianga]

Hi,


2016-12-22 20:11 GMT+01:00 Uwe Kleine-KÃnig <u.kleine-koenig@xxxxxxxxxxxxxx>:
> Hello,
>
> On Thu, Dec 22, 2016 at 02:35:02PM +0100, M'boumba Cedric Madianga wrote:
>> @@ -337,6 +350,16 @@
>>                                       slew-rate = <2>;
>>                               };
>>                       };
>> +
>> +                     i2c1_pins_b: i2c1@0 {
>> +                             pins1 {
>> +                                     pinmux = <STM32F429_PB9_FUNC_I2C1_SDA>;
>> +                                     drive-open-drain;
>> +                             };
>> +                             pins2 {
>> +                                     pinmux = <STM32F429_PB6_FUNC_I2C1_SCL>;
>> +                             };
>
> the second doesn't need the open-drain property? Why?
I thought that open-drain was only needed for SDA line.
But after double-checking I2C specification, it seems that SDA and SCL
lines need open-drain or open-collector to perform the wired-AND
function.
I will do some trials with this config and will fix it in the V8.
Thanks

>
>> +                     };
>>               };
>
> Best regards
> Uwe
>
> --
> Pengutronix e.K.                           | Uwe Kleine-KÃnig            |
> Industrial Linux Solutions                 | http://www.pengutronix.de/  |