Re: [PATCH v3 -next] Input: gpio_keys: set input direction explicitly for gpio keys

From: Sudeep Holla
Date: Thu Nov 17 2016 - 04:48:37 EST

On 17/11/16 01:18, Dmitry Torokhov wrote:
On Wed, Nov 16, 2016 at 06:38:22PM +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@xxxxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
drivers/input/keyboard/gpio_keys.c | 10 +++++++++-
drivers/input/keyboard/gpio_keys_polled.c | 10 +++++++++-
2 files changed, 18 insertions(+), 2 deletions(-)

- Added error handling and error message

diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
index 5576f2ae0b71..ed38a05b3039 100644
--- a/drivers/input/keyboard/gpio_keys.c
+++ b/drivers/input/keyboard/gpio_keys.c
@@ -502,7 +502,7 @@ static int gpio_keys_setup_key(struct platform_device *pdev,
* Legacy GPIO number, so request the GPIO here and
* convert it to descriptor.
- unsigned flags = GPIOF_IN;
+ unsigned flags = 0;

if (button->active_low)

Sudeep, I looked into this aa bit deeper, and I have issue with this
part: in absence of GPIOF_IN devm_gpio_request_one() will attempt to
configure GPIO line as output, which may not work. Because of this I
think we should move gpiod_direction_input() call into the "modern"
branch and leave legacy branch as is.

Does the version below work for you?

Yes it does and in fact I started with something similar and then saw
that I can make it common between legacy and new branch conditions. So I
am fine with the modified version you sent.