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| From | "M'boumba Cedric Madianga" <cedric.madianga@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v7 3/5] ARM: dts: stm32: Add I2C1 support for STM32F429 SoC |
| Date | 2016-12-30 15:40 +0100 |
| Message-ID | <sU6vD-5zf-7@gated-at.bofh.it> (permalink) |
| References | <sRbLc-1E8-3@gated-at.bofh.it> <sRbUS-1Hh-3@gated-at.bofh.it> <sRh4e-52z-19@gated-at.bofh.it> <sRxVo-7o6-5@gated-at.bofh.it> <sU1mh-2n7-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Hi Linus,
2016-12-30 10:07 GMT+01:00 Linus Walleij <linus.walleij@linaro.org>:
> On Fri, Dec 23, 2016 at 2:09 PM, M'boumba Cedric Madianga
> <cedric.madianga@gmail.com> wrote:
>> 2016-12-22 20:11 GMT+01:00 Uwe Kleine-König <u.kleine-koenig@pengutronix.de>:
>>> 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 think I2C SDA/SCL must be open drain by definition.
>
> It also requires pull-up resistors, I guess you have these mounted on the board
> so you do not need pull-up from the pin controller?
Yes, I have 1 pull-up resistor of 1,5K ohm for each line (SDA & SCL)
on the board
>
> Yours,
> Linus Walleij
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[PATCH v7 0/5] Add support for the STM32F4 I2C M'boumba Cedric Madianga <cedric.madianga@gmail.com> - 2016-12-22 14:40 +0100
[PATCH v7 5/5] ARM: configs: stm32: Add I2C support for STM32 defconfig M'boumba Cedric Madianga <cedric.madianga@gmail.com> - 2016-12-22 14:40 +0100
[PATCH v7 4/5] ARM: dts: stm32: Add I2C1 support for STM32429 eval board M'boumba Cedric Madianga <cedric.madianga@gmail.com> - 2016-12-22 14:40 +0100
[PATCH v7 3/5] ARM: dts: stm32: Add I2C1 support for STM32F429 SoC M'boumba Cedric Madianga <cedric.madianga@gmail.com> - 2016-12-22 14:50 +0100
Re: [PATCH v7 3/5] ARM: dts: stm32: Add I2C1 support for STM32F429 SoC Uwe Kleine-König <u.kleine-koenig@pengutronix.de> - 2016-12-22 20:20 +0100
Re: [PATCH v7 3/5] ARM: dts: stm32: Add I2C1 support for STM32F429 SoC "M'boumba Cedric Madianga" <cedric.madianga@gmail.com> - 2016-12-23 14:20 +0100
Re: [PATCH v7 3/5] ARM: dts: stm32: Add I2C1 support for STM32F429 SoC Linus Walleij <linus.walleij@linaro.org> - 2016-12-30 10:10 +0100
Re: [PATCH v7 3/5] ARM: dts: stm32: Add I2C1 support for STM32F429 SoC "M'boumba Cedric Madianga" <cedric.madianga@gmail.com> - 2016-12-30 15:40 +0100
[PATCH v7 2/5] i2c: Add STM32F4 I2C driver M'boumba Cedric Madianga <cedric.madianga@gmail.com> - 2016-12-22 14:50 +0100
Re: [PATCH v7 2/5] i2c: Add STM32F4 I2C driver Uwe Kleine-König <u.kleine-koenig@pengutronix.de> - 2016-12-23 10:10 +0100
Re: [PATCH v7 2/5] i2c: Add STM32F4 I2C driver Uwe Kleine-König <u.kleine-koenig@pengutronix.de> - 2016-12-28 22:30 +0100
Re: [PATCH v7 2/5] i2c: Add STM32F4 I2C driver "M'boumba Cedric Madianga" <cedric.madianga@gmail.com> - 2016-12-28 23:30 +0100
Re: [PATCH v7 2/5] i2c: Add STM32F4 I2C driver "M'boumba Cedric Madianga" <cedric.madianga@gmail.com> - 2017-01-02 14:40 +0100
[PATCH v7 1/5] dt-bindings: Document the STM32 I2C bindings M'boumba Cedric Madianga <cedric.madianga@gmail.com> - 2016-12-22 14:50 +0100
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