Re: [PATCH v1] gpio: keystone: add dsp gpio controller driver

[Grygorii Strashko <grygorii.strashko@xxxxxx>]

Hi Alexander, Linus,

On 07/23/2014 06:19 PM, Alexander Shiyan wrote:
> Wed, 23 Jul 2014 17:10:26 +0200 от Linus Walleij <linus.walleij@xxxxxxxxxx>:
>> On Wed, Jul 16, 2014 at 12:43 PM, Grygorii Strashko
>> <grygorii.strashko@xxxxxx> wrote:
>>
>>> From: Murali Karicheri <m-karicheri2@xxxxxx>
>>>
>>> On Keystone SOCs, ARM host can send interrupts to DSP cores using the
>>> DSP GPIO controller IP. Each DSP GPIO controller provides 28 IRQ signals for
>>> each DSP core. This is one of the component used by the IPC mechanism used
>>> on Keystone SOCs.
>>>
>>> Keystone 2 DSP GPIO controller has specific features:
>>> - each GPIO can be configured only as output pin;
>>> - setting GPIO value to 1 causes IRQ generation on target DSP core;
>>> - reading pin value returns 0 - if IRQ was handled or 1 - IRQ is still
>>>    pending.
>>>
>>> Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>
>>> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
> ...
>> And if you proceed with this, please integrate it with
>> drivers/gpio/gpio-syscon.c, I don't need more special
>> syscons GPIO handlers.

Thanks for your comments.

I'm going to update it for using "gpio-syscon".
But "gpio-syscon" driver itself will need to be modified to support our
device specific callbacks:
- gpiochip.set(): it should set bit 0 to 1 always to physically apply GPIO values
- gpiochip.direction_output(): it should do nothing in our case, just return 0

So, I'll extend struct syscon_gpio_data to support custom implementation of
set/direction_output callbacks. Will it be ok for you?

Best regards,
- grygorii
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