[U-Boot] [PATCH v3 0/5] Add get_alt_function ops

[Michal Simek]

Hi,

On 11.9.2018 09:31, Patrice CHOTARD wrote:
> Hi Michal
> 
> On 09/11/2018 07:51 AM, Michal Simek wrote:
>> On 10.9.2018 18:11, Patrice Chotard wrote:
>>>
>>> This series :
>>>   - Add new gpio ops get_alt_function
>>>   - Add get_function and get_alt_function support to stm32 gpio driver
>>>   - Add get_alt_function test
>>
>>
>> I went quickly over this series and TBH I am not getting what this is
>> for. It looks like that this is the part of pinmux.
>>
>> Can you please elaborate more what this is for?
> 
> Currently, get_function callback returns the state of a gpio
> (GPIOF_INPUT, GPIOF_OUTPUT or GPIO_FUNC).
> 
> If a pin's state is GPIO_FUNC, it's useful to know which alternate
> function is selected for debug purpose.
> 
> As example, on STM32 SoCs, a pins can be configured as GPIO or also
> configured with up to 16 alternate function. Using command "gpio", user
> can retrieve this information as shown below:
> 
> STM32MP> gpio state -a
> 
> Bank GPIOA:
> GPIOA0: unused: 0 [ ]
> GPIOA1: unused: 0 [ ]
> GPIOA2: unused: 0 [ ]
> GPIOA3: unused: 0 [ ]
> GPIOA4: unused: 0 [ ]
> GPIOA5: unused: 0 [ ]
> GPIOA6: unused: 0 [ ]
> GPIOA7: unused: 0 [ ]
> GPIOA8: func: 9
> GPIOA9: func: 10
> GPIOA10: unused: 0 [ ]
> GPIOA11: unused: 0 [ ]
> GPIOA12: unused: 0 [ ]
> GPIOA13: output: 1 [x] red.gpios
> GPIOA14: output: 0 [x] green.gpios
> GPIOA15: unused: 0 [ ]
> 
> It shows that pin 8 and 9 of bank A are configured respectively in
> alternate function 9 and 10.

Can you list that functionality? Isn't it something what should be shown
with a name instead of number?
I expect that user has to go to any decode table to find out what 9 or
10 means.

Thanks,
Michal