From mboxrd@z Thu Jan 1 00:00:00 1970 From: swarren@wwwdotorg.org (Stephen Warren) Date: Wed, 23 May 2012 14:44:03 -0600 Subject: [PATCH RFC v3 3/3] pinctrl: add pinctrl gpio binding support In-Reply-To: <1337779362-31259-3-git-send-email-b29396@freescale.com> References: <1337779362-31259-1-git-send-email-b29396@freescale.com> <1337779362-31259-3-git-send-email-b29396@freescale.com> Message-ID: <4FBD4C13.8080209@wwwdotorg.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 05/23/2012 07:22 AM, Dong Aisheng wrote: > From: Dong Aisheng > > This patch implements a standard common binding for pinctrl gpio ranges. > Each SoC can add gpio ranges through device tree by adding a gpio-maps property > under their pinctrl devices node with the format: > <&gpio $gpio_offset $pin_offset $npin>. > > Then the pinctrl driver can call pinctrl_dt_add_gpio_ranges(pctldev, node) > to parse and register the gpio ranges from device tree. > > Signed-off-by: Dong Aisheng This is mostly good. Just a few comments: > +gpio-maps: 4 integers array, each entry in the array represents a gpio > +range with the format: <&gpio $gpio_offset $pin_offset $count> > +- gpio: phandle pointing at gpio device node > +- gpio_offset: integer, the local offset of $gpio > +- pin_offset: integer, the pin offset or pin id > +- npins: integer, the gpio ranges starting from pin_offset This uses a single cell to represent a GPIO ID within a GPIO controller. The standard GPIO bindings use #gpio-cells, where that's a property in the GPIO controller's node. I wonder if we shouldn't do the same here, and call into the GPIO driver to parse #gpio-cells and give back the Linux GPIO ID, just like of_get_named_gpio_flags() does. This would also make this code able to cope with the GPIO of_xlate function returning a different GPIO chip, which Grant put in place for banked GPIO controllers. > diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c > +int pinctrl_dt_add_gpio_ranges(struct pinctrl_dev *pctldev, The locking I was talking about before is between the following line: > + ranges[i].gc = of_node_to_gpiochip(np_gpio); and this code: > + ranges[i].name = dev_name(pctldev->dev); > + ranges[i].base = ranges[i].gc->base + gpio_offset; > + ranges[i].pin_base = pin_offset; > + ranges[i].npins = npins; If of_node_to_gpiochip() doesn't mark the GPIO chip as "in use", then the module that provides that device could be unloaded between the two blocks of code above. Re: your locking comments in your other email: ranges[i].gc doesn't appear to be used anywhere else in pinctrl, so I think it's OK not to lock the GPIO chip for any more time than between the above two blocks of code. Finally, just a minor nit: > + ranges[i].gc = of_node_to_gpiochip(np_gpio); > + if (!ranges[i].gc) { > + dev_err(pctldev->dev, > + "can not find gpio chip of node(%s)\n", > + np_gpio->name); > + of_node_put(np_gpio); > + return -EPROBE_DEFER; > + } > + > + of_node_put(np_gpio); could be slightly simpler: + ranges[i].gc = of_node_to_gpiochip(np_gpio); + of_node_put(np_gpio); <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< + if (!ranges[i].gc) { + dev_err(pctldev->dev, + "can not find gpio chip of node(%s)\n", + np_gpio->name); + return -EPROBE_DEFER; + } From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH RFC v3 3/3] pinctrl: add pinctrl gpio binding support Date: Wed, 23 May 2012 14:44:03 -0600 Message-ID: <4FBD4C13.8080209@wwwdotorg.org> References: <1337779362-31259-1-git-send-email-b29396@freescale.com> <1337779362-31259-3-git-send-email-b29396@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1337779362-31259-3-git-send-email-b29396@freescale.com> Sender: linux-kernel-owner@vger.kernel.org To: Dong Aisheng , Grant Likely Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linus.walleij@stericsson.com, devicetree-discuss , Rob Herring List-Id: devicetree@vger.kernel.org On 05/23/2012 07:22 AM, Dong Aisheng wrote: > From: Dong Aisheng > > This patch implements a standard common binding for pinctrl gpio ranges. > Each SoC can add gpio ranges through device tree by adding a gpio-maps property > under their pinctrl devices node with the format: > <&gpio $gpio_offset $pin_offset $npin>. > > Then the pinctrl driver can call pinctrl_dt_add_gpio_ranges(pctldev, node) > to parse and register the gpio ranges from device tree. > > Signed-off-by: Dong Aisheng This is mostly good. Just a few comments: > +gpio-maps: 4 integers array, each entry in the array represents a gpio > +range with the format: <&gpio $gpio_offset $pin_offset $count> > +- gpio: phandle pointing at gpio device node > +- gpio_offset: integer, the local offset of $gpio > +- pin_offset: integer, the pin offset or pin id > +- npins: integer, the gpio ranges starting from pin_offset This uses a single cell to represent a GPIO ID within a GPIO controller. The standard GPIO bindings use #gpio-cells, where that's a property in the GPIO controller's node. I wonder if we shouldn't do the same here, and call into the GPIO driver to parse #gpio-cells and give back the Linux GPIO ID, just like of_get_named_gpio_flags() does. This would also make this code able to cope with the GPIO of_xlate function returning a different GPIO chip, which Grant put in place for banked GPIO controllers. > diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c > +int pinctrl_dt_add_gpio_ranges(struct pinctrl_dev *pctldev, The locking I was talking about before is between the following line: > + ranges[i].gc = of_node_to_gpiochip(np_gpio); and this code: > + ranges[i].name = dev_name(pctldev->dev); > + ranges[i].base = ranges[i].gc->base + gpio_offset; > + ranges[i].pin_base = pin_offset; > + ranges[i].npins = npins; If of_node_to_gpiochip() doesn't mark the GPIO chip as "in use", then the module that provides that device could be unloaded between the two blocks of code above. Re: your locking comments in your other email: ranges[i].gc doesn't appear to be used anywhere else in pinctrl, so I think it's OK not to lock the GPIO chip for any more time than between the above two blocks of code. Finally, just a minor nit: > + ranges[i].gc = of_node_to_gpiochip(np_gpio); > + if (!ranges[i].gc) { > + dev_err(pctldev->dev, > + "can not find gpio chip of node(%s)\n", > + np_gpio->name); > + of_node_put(np_gpio); > + return -EPROBE_DEFER; > + } > + > + of_node_put(np_gpio); could be slightly simpler: + ranges[i].gc = of_node_to_gpiochip(np_gpio); + of_node_put(np_gpio); <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< + if (!ranges[i].gc) { + dev_err(pctldev->dev, + "can not find gpio chip of node(%s)\n", + np_gpio->name); + return -EPROBE_DEFER; + }