linux-kernel - Re: [PATCH v2 -next] Input: gpio_keys: set input direction explicitly for gpio keys

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Date:   Wed, 16 Nov 2016 17:42:15 +0000
From:   Sudeep Holla <sudeep.holla@....com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     Sudeep Holla <sudeep.holla@....com>, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Linus Walleij <linus.walleij@...aro.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>
Subject: Re: [PATCH v2 -next] Input: gpio_keys: set input direction explicitly
 for gpio keys



On 16/11/16 17:36, Dmitry Torokhov wrote:
> On Wed, Nov 16, 2016 at 01:42:14PM +0000, Sudeep Holla wrote:
>> Commit 700a38b27eef ("Input: gpio_keys - switch to using generic device
>> properties") switched to use generic device properties for GPIO keys and
>> commit 5feeca3c1e39 ("Input: gpio_keys - add support for GPIO descriptors")
>> switched from legacy GPIO numbers to GPIO descriptors.
>>
>> Previously devm_gpio_request_one was explicitly passed GPIOF_DIR_IN flag
>> to set the GPIO direction as input. However devm_get_gpiod_from_child
>> doesn't have such provisions and hence fwnode_get_named_gpiod can't set
>> it as input.
>>
>> This breaks few platforms with the following error:
>> " gpiochip_lock_as_irq: tried to flag a GPIO set as output for IRQ
>>   unable to lock HW IRQ <n> for IRQ
>>   genirq: Failed to request resources for POWER (irq <x>) on irqchip
>>   gpio_keys: Unable to claim irq <x>; error -22
>>   gpio-keys: probe failed with error -22 "
>>
>> This patch fixes the issue by setting input direction explicitly for
>> gpio input keys. It also remove the existing GPIOF_DIR_IN flag setting
>> for the legacy gpios and merges into single gpiod_direction_input call.
>>
>> Fixes: 700a38b27eef ("Input: gpio_keys - switch to using generic device properties")
>> Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>
>> Cc: Linus Walleij <linus.walleij@...aro.org>
>> Cc: Geert Uytterhoeven <geert+renesas@...der.be>
>> Cc: Mika Westerberg <mika.westerberg@...ux.intel.com>
>> Signed-off-by: Sudeep Holla <sudeep.holla@....com>
>> ---
>>  drivers/input/keyboard/gpio_keys.c        | 5 ++++-
>>  drivers/input/keyboard/gpio_keys_polled.c | 5 ++++-
>>  2 files changed, 8 insertions(+), 2 deletions(-)
>>
>> v1->v2:
>> 	- Fix the build(had sent a wrong version by accident)
>>
>> Hi Dmitry,
>>
>> The other option would be to pass the flag explicitly and add support to
>> handle it in the path devm_get_gpiod_from_child would take.
>
> Hi Sudeep,
>
> No, I think explicitly configuring it for input is good (at least for
> now), but we need error handling.
>

Sure, a quick glance makes me think: all I need is to return the error
as everything is handled by devm_* APIs. If so I will respin with that
change, otherwise please let me know if I am missing anything here.

-- 
Regards,
Sudeep