[PATCH] gpio: mxs: implement get_direction callback

[Janusz Użycki]

Hello Uwe,

W dniu 2014-11-17 o 19:42, Uwe Kleine-König pisze:
> Hello Janusz,
>
> On Mon, Nov 17, 2014 at 06:07:53PM +0100, Janusz Użycki wrote:
>>> It looks there could be one more helper useful.
>>> Both atmel_serial.c and mxs-auart.c checks if the line is
>>> supported by mctrl_gpio.
>>> One time it is eg.:
>>> (s->gpio_irq[UART_GPIO_DCD] > 0)
>>> another time it is eg.:
>>> IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(s->gpios, UART_GPIO_RTS))
>>>
>>> The first one is no possible now. The second seems rude.
>>> bool mctrl_gpio_is_gpio((struct mctrl_gpios *gpios, enum
>>> mctrl_gpio_idx gidx);
>>> The name is hard. Moreover the implementation could be very similar
>>> to mctrl_gpio_to_gpiod(). Any ideas?
>> The differences:
>> - faster
>> - not exported
>> - used mainly in uart's interrupt
>> - assumes that struct mctrl_gpios *gpios exists
> I wonder why you need it at all?!

If the line is not supported by gpio it could be supported by native 
uart's hardware
if possible. There are different configurations. One port has the lines, 
other
which uses the same driver doesn't have.
Let's look at disable/enable_ms() in atmet_serial.c.
In mxs-auart DMA is not used if CTS or RTS is gpio line (timming).

best regards
Janusz

>
> Best regards
> Uwe
>