2018-02-16 19:36:27

by Daniel Kurtz

Subject: [PATCH] pinctrl/amd: add get_direction handler

On boot, gpiochip_add_data() initializes the FLAG_IS_OUT bit in
desc->flags iff its gpio_chip does not have ->direction_input() handler,
else it is initialized to 0, which implies the GPIO is an "input".

Later, the sysfs "direction" handler will use gpiod_get_direction() to
get the current direction, but if no ->get_direction() handler is
installed, the result will just be the current (initial) value of flags,
which will always be OUT irregardless of the initial register value.

Add a get_direction() handler to pinctrl-amd to fix this and always
provide the correct value for direction.

Signed-off-by: Daniel Kurtz <[email protected]>
---
drivers/pinctrl/pinctrl-amd.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
index 61d830c2bc17..281b700fe7e9 100644
--- a/drivers/pinctrl/pinctrl-amd.c
+++ b/drivers/pinctrl/pinctrl-amd.c
@@ -40,6 +40,19 @@
#include "pinctrl-utils.h"
#include "pinctrl-amd.h"

+static int amd_gpio_get_direction(struct gpio_chip *gc, unsigned offset)
+{
+ unsigned long flags;
+ u32 pin_reg;
+ struct amd_gpio *gpio_dev = gpiochip_get_data(gc);
+
+ raw_spin_lock_irqsave(&gpio_dev->lock, flags);
+ pin_reg = readl(gpio_dev->base + offset * 4);
+ raw_spin_unlock_irqrestore(&gpio_dev->lock, flags);
+
+ return !(pin_reg & BIT(OUTPUT_ENABLE_OFF));
+}
+
static int amd_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
{
unsigned long flags;
@@ -845,6 +858,7 @@ static int amd_gpio_probe(struct platform_device *pdev)
#endif

gpio_dev->pdev = pdev;
+ gpio_dev->gc.get_direction = amd_gpio_get_direction;
gpio_dev->gc.direction_input = amd_gpio_direction_input;
gpio_dev->gc.direction_output = amd_gpio_direction_output;
gpio_dev->gc.get = amd_gpio_get_value;
--
2.16.1.291.g4437f3f132-goog

2018-02-22 14:54:19

by Linus Walleij

Subject: Re: [PATCH] pinctrl/amd: add get_direction handler

On Fri, Feb 16, 2018 at 8:12 PM, Daniel Kurtz <[email protected]> wrote:

> On boot, gpiochip_add_data() initializes the FLAG_IS_OUT bit in
> desc->flags iff its gpio_chip does not have ->direction_input() handler,
> else it is initialized to 0, which implies the GPIO is an "input".
>
> Later, the sysfs "direction" handler will use gpiod_get_direction() to
> get the current direction, but if no ->get_direction() handler is
> installed, the result will just be the current (initial) value of flags,
> which will always be OUT irregardless of the initial register value.
>
> Add a get_direction() handler to pinctrl-amd to fix this and always
> provide the correct value for direction.
>
> Signed-off-by: Daniel Kurtz <[email protected]>

Hm, please don't use the sysfs... use the chardev!

Anyways, patch is fine and applied.

Yours,
Linus Walleij