[U-Boot] [PATCH] mx6: Add IOMUX_CONFIG_SION flag to all GPIO pins

Otavio Salvador otavio at ossystems.com.br
Tue Oct 1 14:01:48 CEST 2013


On Tue, Oct 1, 2013 at 5:33 AM, Stefano Babic <sbabic at denx.de> wrote:
> Hi Otavio,
>
> On 30/09/2013 00:15, Otavio Salvador wrote:
>> The IOMUX_CONFIG_SION allows for reading PAD value from PSR register.
>>
>> The following quote from the datasheet:
>>
>> ,----
>> | ...
>> | 28.4.2.2 GPIO Write Mode
>> | The programming sequence for driving output signals should be as follows:
>> | 1. Configure IOMUX to select GPIO mode (Via IOMUXC), also enable SION if need
>> | to read loopback pad value through PSR
>> | 2. Configure GPIO direction register to output (GPIO_GDIR[GDIR] set to 1b).
>> | 3. Write value to data register (GPIO_DR).
>> | ...
>> `----
>>
>> This fixes the gpio_get_value to properly work when a GPIO is set for
>> output and has no conflicts.
>>
>> Thanks for Benoît Thébaudeau <benoit.thebaudeau at advansee.com>, Fabio
>> Estevam <fabio.estevam at freescale.com> and Eric Bénard
>> <eric at eukrea.com> for helping to properly trace this down.
>>
>> Signed-off-by: Otavio Salvador <otavio at ossystems.com.br>
>> ---
>
> I come later in the discussion, but I see you all have found the
> solution ;-).
>
> I suggest you add in the commit message that this patch is only for
> i.MX6 (if you do not plan to extend it to the other i.MXes...), so that
> we can track that the same must be done also for the other SOCs.

I think this is clear from the commit prefix.

I am under heavy load now and I cannot check their datasheet to verify
if they all need this or not.

If someone does not does it, I can take a look for sure.

-- 
Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://code.ossystems.com.br
Mobile: +55 (53) 9981-7854            Mobile: +1 (347) 903-9750


More information about the U-Boot mailing list