linux-kernel - [PATCH 0/5] gpio: refactor of_parse_own_gpio() and of_get_named_gpiod

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Message-Id: <1465898827-2229-1-git-send-email-yamada.masahiro@socionext.com>
Date:	Tue, 14 Jun 2016 19:07:02 +0900
From:	Masahiro Yamada <yamada.masahiro@...ionext.com>
To:	linux-gpio@...r.kernel.org
Cc:	Masahiro Yamada <yamada.masahiro@...ionext.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Alexandre Courbot <gnurou@...il.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 0/5] gpio: refactor of_parse_own_gpio() and of_get_named_gpiod_flags()

I found one bug in of_parse_own_gpio(); of_gpiochip_find_and_xlate()
fills gg_data->out_gpio with an error pointer if the .of_xlate()
callback fails, but of_parse_own_gpio() only checks whether the
out_gpio is NULL.  This is a problem because the error pointer might
be passed to the desc_to_gpio() in the failure path.

At first, I was trying to fix it with the following patch:

    @@ -165,6 +165,9 @@ static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
                return ERR_PTR(ret);

        gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
    +   if (IS_ERR(gg_data.out_gpio)){
    +           return gg_data.out_gpio;
    +   }
        if (!gg_data.out_gpio) {
                if (np->parent == np)
                        return ERR_PTR(-ENXIO);

But, after reading this code around, I thought it was more complex
than needed.  So, I decided to clean-up it instead of fix the bug.

Talking about of_parse_own_gpio(), does it need to call gpiochip_find()
in the first place?

The caller of this function, of_gpiochip_scan_gpios() already knows the
gpio_chip.  I want to make the implementation more straight-forward.

Masahiro Yamada (5):
  gpio: of: optimize "gpios" property parsing of of_parse_own_gpio()
  gpio: of: drop needless gpio_chip look-up in of_parse_own_gpio()
  gpio: of: move chip->of_gpio_n_cells checking to of_gpiochip_add()
  gpio: of: remove of_gpiochip_and_xlate() and struct gg_data
  gpio: of: factor out common code to a new helper function

 drivers/gpio/gpiolib-of.c | 126 +++++++++++++++++++++-------------------------
 1 file changed, 58 insertions(+), 68 deletions(-)

-- 
1.9.1