[v2] drivers/pinctrl: grab default handles from device core

Message ID	1355343907-11535-1-git-send-email-linus.walleij@stericsson.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org> From: Linus Walleij <linus.walleij@stericsson.com> To: <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org> Subject: [PATCH v2] drivers/pinctrl: grab default handles from device core Date: Wed, 12 Dec 2012 21:25:07 +0100 Message-ID: <1355343907-11535-1-git-send-email-linus.walleij@stericsson.com> MIME-Version: 1.0 summary: Content analysis details: (-4.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [207.126.144.119 listed in list.dnswl.org] -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>, Kevin Hilman <khilman@ti.com>, Ulf Hansson <ulf.hansson@linaro.org>, Mark Brown <broonie@opensource.wolfsonmicro.com>, Russell King <linux@arm.linux.org.uk>, Benoit Cousson <b-cousson@ti.com>, Linus Walleij <linus.walleij@linaro.org>, Dmitry Torokhov <dmitry.torokhov@gmail.com>, Felipe Balbi <balbi@ti.com>, Rickard Andersson <rickard.andersson@stericsson.com>, "Rafael J. Wysocki" <rjw@sisk.pl>, Mitch Bradley <wmb@firmworks.com>, Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Precedence: list Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt index da40efb..68836e5 100644 --- a/Documentation/pinctrl.txt +++ b/Documentation/pinctrl.txt @@ -972,6 +972,18 @@ pinmux core. Pin control requests from drivers ================================= +When a device driver is about to probe the device core will automatically +attempt to issue pinctrl_get_select_default() on these devices. +This way driver writers do not need to add any of the boilerplate code +of the type found below. However when doing fine-grained state selection +and not using the "default" state, you may have to do some device driver +handling of the pinctrl handles and states. + +So if you just want to put the pins for a certain device into the default +state and be done with it, there is nothing you need to do besides +providing the proper mapping table. The device core will take care of +the rest. + Generally it is discouraged to let individual drivers get and enable pin control. So if possible, handle the pin control in platform code or some other place where you have access to all the affected struct device * pointers. In @@ -1097,9 +1109,9 @@ situations that can be electrically unpleasant, you will certainly want to mux in and bias pins in a certain way before the GPIO subsystems starts to deal with them. -The above can be hidden: using pinctrl hogs, the pin control driver may be -setting up the config and muxing for the pins when it is probing, -nevertheless orthogonal to the GPIO subsystem. +The above can be hidden: using the device core, the pinctrl core may be +setting up the config and muxing for the pins right before the device is +probing, nevertheless orthogonal to the GPIO subsystem. But there are also situations where it makes sense for the GPIO subsystem to communicate directly with with the pinctrl subsystem, using the latter @@ -1144,6 +1156,12 @@ PIN_MAP_MUX_GROUP_HOG_DEFAULT("pinctrl-foo", NULL /* group */, "power_func") This gives the exact same result as the above construction. +This should not be used for any kind of device which is represented in +the device model, as the pinctrl core will attempt to do the equal of +pinctrl_get_select_default() for these devices right before their device +drivers are probed, so hogging these will just make the model look +strange. Instead put in proper map entries. + Runtime pinmuxing ================= diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 5aa2d70..4e22ce3 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -21,6 +21,7 @@ endif obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o obj-$(CONFIG_REGMAP) += regmap/ obj-$(CONFIG_SOC_BUS) += soc.o +obj-$(CONFIG_PINCTRL) += pinctrl.o ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG diff --git a/drivers/base/dd.c b/drivers/base/dd.c index e3bbed8..65631015 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -24,6 +24,7 @@ #include <linux/wait.h> #include <linux/async.h> #include <linux/pm_runtime.h> +#include <linux/pinctrl/devinfo.h> #include "base.h" #include "power/power.h" @@ -269,6 +270,12 @@ static int really_probe(struct device *dev, struct device_driver *drv) WARN_ON(!list_empty(&dev->devres_head)); dev->driver = drv; + + /* If using pinctrl, bind pins now before probing */ + ret = pinctrl_bind_pins(dev); + if (ret) + goto probe_failed; + if (driver_sysfs_add(dev)) { printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", __func__, dev_name(dev)); diff --git a/drivers/base/pinctrl.c b/drivers/base/pinctrl.c new file mode 100644 index 0000000..edbf8e1 --- /dev/null +++ b/drivers/base/pinctrl.c @@ -0,0 +1,81 @@ +/* + * Driver core interface to the pinctrl subsystem. + * + * Copyright (C) 2012 ST-Ericsson SA + * Written on behalf of Linaro for ST-Ericsson + * Based on bits of regulator core, gpio core and clk core + * + * Author: Linus Walleij <linus.walleij@linaro.org> + * + * License terms: GNU General Public License (GPL) version 2 + */ + +#include <linux/device.h> +#include <linux/pinctrl/devinfo.h> +#include <linux/pinctrl/consumer.h> +#include <linux/slab.h> + +/** + * pinctrl_bind_pins() - called by the device core before probe + * @dev: the device that is just about to probe + */ +int pinctrl_bind_pins(struct device *dev) +{ + struct dev_pin_info *dpi; + int ret; + + /* Allocate a pin state container on-the-fly */ + if (!dev->pins) { + dpi = devm_kzalloc(dev, sizeof(*dpi), GFP_KERNEL); + if (!dpi) + return -ENOMEM; + } else + dpi = dev->pins; + + /* + * Check if we already have a pinctrl handle, as we may arrive here + * after a deferral in the state selection below + */ + if (!dpi->p) { + dpi->p = devm_pinctrl_get(dev); + if (IS_ERR_OR_NULL(dpi->p)) { + int ret = PTR_ERR(dpi->p); + + dev_dbg(dev, "no pinctrl handle\n"); + /* Only return deferrals */ + if (ret == -EPROBE_DEFER) + return ret; + return 0; + } + } + + /* + * For a newly allocated info struct, here is where we keep it, + * since at this point it actually contains something. + */ + dev->pins = dpi; + + /* + * We may have looked up the state earlier as well. + */ + if (!dpi->default_state) { + dpi->default_state = pinctrl_lookup_state(dpi->p, + PINCTRL_STATE_DEFAULT); + if (IS_ERR(dpi->default_state)) { + dev_dbg(dev, "no default pinctrl state\n"); + return 0; + } + } + + ret = pinctrl_select_state(dpi->p, dpi->default_state); + if (ret) { + dev_dbg(dev, "failed to activate default pinctrl state\n"); + + /* Only return deferrals */ + if (ret == -EPROBE_DEFER) + return ret; + return 0; + } + + return 0; +} diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c index 5b4885c..6947bf0 100644 --- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -734,9 +734,16 @@ static struct pinctrl *pinctrl_get_locked(struct device *dev) if (WARN_ON(!dev)) return ERR_PTR(-EINVAL); + /* + * See if somebody else (such as the device core) has already + * obtained a handle to the pinctrl for this device. In that case, + * return another pointer to it. + */ p = find_pinctrl(dev); - if (p != NULL) - return ERR_PTR(-EBUSY); + if (p != NULL) { + dev_dbg(dev, "obtain a copy of previously claimed pinctrl\n"); + return p; + } return create_pinctrl(dev); } diff --git a/include/linux/device.h b/include/linux/device.h index 86ef6ab..86d11f7 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -21,6 +21,7 @@ #include <linux/compiler.h> #include <linux/types.h> #include <linux/mutex.h> +#include <linux/pinctrl/devinfo.h> #include <linux/pm.h> #include <linux/atomic.h> #include <linux/ratelimit.h> @@ -605,6 +606,8 @@ struct device_dma_parameters { * @pm_domain: Provide callbacks that are executed during system suspend, * hibernation, system resume and during runtime PM transitions * along with subsystem-level and driver-level callbacks. + * @pins: For device pin management. + * See Documentation/pinctrl.txt for details. * @numa_node: NUMA node this device is close to. * @dma_mask: Dma mask (if dma'ble device). * @coherent_dma_mask: Like dma_mask, but for alloc_coherent mapping as not all @@ -656,6 +659,10 @@ struct device { struct dev_pm_info power; struct dev_pm_domain *pm_domain; +#ifdef CONFIG_PINCTRL + struct dev_pin_info *pins; +#endif + #ifdef CONFIG_NUMA int numa_node; /* NUMA node this device is close to */ #endif diff --git a/include/linux/pinctrl/devinfo.h b/include/linux/pinctrl/devinfo.h new file mode 100644 index 0000000..6e5f8a9 --- /dev/null +++ b/include/linux/pinctrl/devinfo.h @@ -0,0 +1,45 @@ +/* + * Per-device information from the pin control system. + * This is the stuff that get included into the device + * core. + * + * Copyright (C) 2012 ST-Ericsson SA + * Written on behalf of Linaro for ST-Ericsson + * This interface is used in the core to keep track of pins. + * + * Author: Linus Walleij <linus.walleij@linaro.org> + * + * License terms: GNU General Public License (GPL) version 2 + */ + +#ifndef PINCTRL_DEVINFO_H +#define PINCTRL_DEVINFO_H + +#ifdef CONFIG_PINCTRL + +/* The device core acts as a consumer toward pinctrl */ +#include <linux/pinctrl/consumer.h> + +/** + * struct dev_pin_info - pin state container for devices + * @p: pinctrl handle for the containing device + * @default_state: the default state for the handle, if found + */ +struct dev_pin_info { + struct pinctrl *p; + struct pinctrl_state *default_state; +}; + +extern int pinctrl_bind_pins(struct device *dev); + +#else + +/* Stubs if we're not using pinctrl */ + +static inline int pinctrl_bind_pins(struct device *dev) +{ + return 0; +} + +#endif /* CONFIG_PINCTRL */ +#endif /* PINCTRL_DEVINFO_H */

[v2] drivers/pinctrl: grab default handles from device core

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