[PATCH v2] gpio: of: fix GPIO drivers with multiple gpio_chip for a single node

[PATCH v2] gpio: of: fix GPIO drivers with multiple gpio_chip for a single node

[Masahiro Yamada]

Sylvain Lemieux reports the LPC32xx GPIO driver is broken since
commit 762c2e46c059 ("gpio: of: remove of_gpiochip_and_xlate() and
struct gg_data").  Probably, gpio-etraxfs.c and gpio-davinci.c are
broken too.

Those drivers register multiple gpio_chip that are associated to a
single OF node, and their own .of_xlate() checks if the passed
gpio_chip is valid.

Now, the problem is of_find_gpiochip_by_node() returns the first
gpio_chip found to match the given node.  So, .of_xlate() fails,
except for the first GPIO bank.

Reverting the commit could be a solution, but I do not want to go
back to the mess of struct gg_data.  Another solution here is to
take the match by a node pointer and the success of .of_xlate().
It is a bit clumsy to call .of_xlate twice; for gpio_chip matching
and for really getting the gpio_desc index.  Perhaps, our long-term
goal might be to convert the drivers to single chip registration,
but this commit will solve the problem until then.

Fixes: 762c2e46c059 ("gpio: of: remove of_gpiochip_and_xlate() and struct gg_data")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reported-by: Sylvain Lemieux <slemieux.tyco@gmail.com>
Tested-by: David Lechner <david@lechnology.com>
---

Changes in v2:
  - correcton pointed out by Sylvain:
       chip->of_xlate(chip, gpiospec, NULL) >= 0

 drivers/gpio/gpiolib-of.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index ecad3f0..193f15d 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -26,14 +26,18 @@
 
 #include "gpiolib.h"
 
-static int of_gpiochip_match_node(struct gpio_chip *chip, void *data)
+static int of_gpiochip_match_node_and_xlate(struct gpio_chip *chip, void *data)
 {
-	return chip->gpiodev->dev.of_node == data;
+	struct of_phandle_args *gpiospec = data;
+
+	return chip->gpiodev->dev.of_node == gpiospec->np &&
+				chip->of_xlate(chip, gpiospec, NULL) >= 0;
 }
 
-static struct gpio_chip *of_find_gpiochip_by_node(struct device_node *np)
+static struct gpio_chip *of_find_gpiochip_by_xlate(
+					struct of_phandle_args *gpiospec)
 {
-	return gpiochip_find(np, of_gpiochip_match_node);
+	return gpiochip_find(gpiospec, of_gpiochip_match_node_and_xlate);
 }
 
 static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip,
@@ -79,7 +83,7 @@ struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
 		return ERR_PTR(ret);
 	}
 
-	chip = of_find_gpiochip_by_node(gpiospec.np);
+	chip = of_find_gpiochip_by_xlate(&gpiospec);
 	if (!chip) {
 		desc = ERR_PTR(-EPROBE_DEFER);
 		goto out;
-- 
1.9.1

Re: [PATCH v2] gpio: of: fix GPIO drivers with multiple gpio_chip for a single node

[Linus Walleij]

On Tue, Oct 25, 2016 at 3:47 AM, Masahiro Yamada
<yamada.masahiro@socionext.com> wrote:

> Sylvain Lemieux reports the LPC32xx GPIO driver is broken since
> commit 762c2e46c059 ("gpio: of: remove of_gpiochip_and_xlate() and
> struct gg_data").  Probably, gpio-etraxfs.c and gpio-davinci.c are
> broken too.
>
> Those drivers register multiple gpio_chip that are associated to a
> single OF node, and their own .of_xlate() checks if the passed
> gpio_chip is valid.
>
> Now, the problem is of_find_gpiochip_by_node() returns the first
> gpio_chip found to match the given node.  So, .of_xlate() fails,
> except for the first GPIO bank.
>
> Reverting the commit could be a solution, but I do not want to go
> back to the mess of struct gg_data.  Another solution here is to
> take the match by a node pointer and the success of .of_xlate().
> It is a bit clumsy to call .of_xlate twice; for gpio_chip matching
> and for really getting the gpio_desc index.  Perhaps, our long-term
> goal might be to convert the drivers to single chip registration,
> but this commit will solve the problem until then.
>
> Fixes: 762c2e46c059 ("gpio: of: remove of_gpiochip_and_xlate() and struct gg_data")
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> Reported-by: Sylvain Lemieux <slemieux.tyco@gmail.com>
> Tested-by: David Lechner <david@lechnology.com>
> ---
>
> Changes in v2:
>   - correcton pointed out by Sylvain:
>        chip->of_xlate(chip, gpiospec, NULL) >= 0

Patch applied for fixes.

Yours,
Linus Walleij