[U-Boot] [RFC PATCH 1/3] at91: add new gpio pin macros

[Heiko Schocher]

Hello Andreas,

Am 30.10.2013 19:59, schrieb Andreas Bießmann:
> Hi Jens,
>
> On 30.10.13 18:19, Jens Scharsig wrote:
>> Am 30.10.2013 11:39, schrieb Andreas Bießmann:
>>> Hi Bo,
>>>
>>> +Jens, he did the rewrite of the at91 gpio driver.
>>>
>>
>>>
>>> I think this is a job for gpio_is_valid() then. How is this case handled
>>> in kernel?
>>>
>>> Here are a few things to discuss. First of all I'd like to get some
>>> insights why the at91 gpio API was changed back in 2010. It was a plain
>>> number before and was changed to PORT + PIN as two separate parameters.
>>> Jens, could you please shed some light on this?
>>>
>>
>> Sorry, but I don't remember me why we do this. I think, it was a
>> compromise between number of changes and code size.
>
> found it:
> http://article.gmane.org/gmane.comp.boot-loaders.u-boot/74579
>
> ---8<---
> Jens Scharsig wrote:
>> +#endif
>> +
>> +#define AT91_PIN_TO_MASK(x)	(1<<x)
>> +#define AT91_PORTPIN(PORT, PIN)	((0x0##PORT - 9) * 32 + ((PIN)&  0x1F))
>> +#define	AT91_PIO_PORTA		0x0
>> +#define	AT91_PIO_PORTB		0x1
>> +#define	AT91_PIO_PORTC		0x2
>> +#define	AT91_PIO_PORTD		0x3
>> +#define	AT91_PIO_PORTE		0x4
>> +
>
> Tom.Rix at windriver.com:
> Is this necessary?
> You are packing arguments that you are passing to the gpio functions.
> It would be better if there were seperate port, pin parameters than
> combining and then uncombining.
> Please change this.
> --->8---
>
> I think we should shift toward the linux kernel at91_pio API which uses
> a single number for identifying the GPIO. Any complaints?

Full Ack.

> I think it would make sense to retain some PORT + MASK functions to
> easily switch multiple I/O in one go. What do you think about?

That would be good.

bye,
Heiko
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