From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladimir Zapolskiy Subject: Re: [RFC PATCH] gpio: of: fix GPIO drivers with multiple gpio_chip for a single node Date: Tue, 25 Oct 2016 01:07:13 +0300 Message-ID: References: <1477295033-6008-1-git-send-email-yamada.masahiro@socionext.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mleia.com ([178.79.152.223]:37157 "EHLO mail.mleia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750813AbcJXWHP (ORCPT ); Mon, 24 Oct 2016 18:07:15 -0400 In-Reply-To: <1477295033-6008-1-git-send-email-yamada.masahiro@socionext.com> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Masahiro Yamada , linux-gpio@vger.kernel.org Cc: Linus Walleij , Alexandre Courbot , linux-kernel@vger.kernel.org Hi Masahiro, On 24.10.2016 10:43, Masahiro Yamada 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 as well. > > 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, the long-term > goal might be to convert drivers to single chip registration, but > this commit will solve the problem until then. > > Signed-off-by: Masahiro Yamada > Reported-by: Fixes: 762c2e46c059 ("gpio: of: remove of_gpiochip_and_xlate() and struct gg_data") > --- > > 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..f996596 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); That's an awful but hopefully safe hack to support 3-4 broken GPIO drivers, however it should work with a correction given by Sylvain. Here I would recommend to expand the statement, so it will be easier to simplify it in future: if (chip->gpiodev->dev.of_node != gpiospec->np) return 0; if (chip->of_xlate(chip, gpiospec, NULL) < 0) return 0; return 1; As far as I can say it should work correctly with of_gpio_simple_xlate(), brcmstb_gpio_of_xlate(), lpc32xx_of_xlate(), davinci_gpio_of_xlate(), pxa_gpio_of_xlate() and etraxfs_gpio_of_xlate() flavours. > } > > -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; > -- With best wishes, Vladimir