From patchwork Wed Feb 13 17:34:26 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philipp Zabel X-Patchwork-Id: 2138011 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id 1B1503FCA4 for ; Wed, 13 Feb 2013 17:39:18 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1U5gGF-0003GS-Cv; Wed, 13 Feb 2013 17:36:47 +0000 Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1U5gEE-00021q-PO for linux-arm-kernel@lists.infradead.org; Wed, 13 Feb 2013 17:34:52 +0000 Received: from dude.hi.pengutronix.de ([10.1.0.7] helo=dude.pengutronix.de) by metis.ext.pengutronix.de with esmtp (Exim 4.72) (envelope-from ) id 1U5gE9-0003FX-Tx; Wed, 13 Feb 2013 18:34:37 +0100 From: Philipp Zabel To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 2/8] reset: Add reset controller API Date: Wed, 13 Feb 2013 18:34:26 +0100 Message-Id: <1360776872-18584-3-git-send-email-p.zabel@pengutronix.de> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1360776872-18584-1-git-send-email-p.zabel@pengutronix.de> References: <1360776872-18584-1-git-send-email-p.zabel@pengutronix.de> X-SA-Exim-Connect-IP: 10.1.0.7 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130213_123443_294311_AEA7AEEA X-CRM114-Status: GOOD ( 22.76 ) X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Marek Vasut , Fabio Estevam , Mike Turquette , Philipp Zabel , Stephen Warren , Sascha Hauer , kernel@pengutronix.de, Shawn Guo , devicetree-discuss@lists.ozlabs.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org This adds a simple API for devices to request being reset by separate reset controller hardware and implements the reset signal device tree binding. Signed-off-by: Philipp Zabel Reviewed-by: Stephen Warren --- Changes since v1: - Added missing header files. - Fixed reset_controller_register comment. - Added missing reset_controller_unregister. - Made reset_control_reset/assert/deassert return -ENOSYS if not implemented by the reset controller driver. - Fixed reset_control_put to not access rstc after freeing it. - Whitespace fixes --- drivers/Kconfig | 2 + drivers/Makefile | 3 + drivers/reset/Kconfig | 9 ++ drivers/reset/Makefile | 1 + drivers/reset/core.c | 238 ++++++++++++++++++++++++++++++++++++++ include/linux/reset-controller.h | 39 +++++++ include/linux/reset.h | 17 +++ 7 files changed, 309 insertions(+) create mode 100644 drivers/reset/Kconfig create mode 100644 drivers/reset/Makefile create mode 100644 drivers/reset/core.c create mode 100644 include/linux/reset-controller.h create mode 100644 include/linux/reset.h diff --git a/drivers/Kconfig b/drivers/Kconfig index 202fa6d..847f8e3 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -162,4 +162,6 @@ source "drivers/irqchip/Kconfig" source "drivers/ipack/Kconfig" +source "drivers/reset/Kconfig" + endmenu diff --git a/drivers/Makefile b/drivers/Makefile index 4af933d..682fb7c 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -42,6 +42,9 @@ ifndef CONFIG_ARCH_USES_GETTIMEOFFSET obj-y += clocksource/ endif +# reset controllers early, since gpu drivers might rely on them to initialize +obj-$(CONFIG_RESET_CONTROLLER) += reset/ + # tty/ comes before char/ so that the VT console is the boot-time # default. obj-y += tty/ diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig new file mode 100644 index 0000000..66ac385 --- /dev/null +++ b/drivers/reset/Kconfig @@ -0,0 +1,9 @@ +menuconfig RESET_CONTROLLER + bool "Reset Controller Support" + help + Generic Reset Controller support. + + This framework is designed to abstract reset handling of devices + via GPIOs or SoC-internal reset controller modules. + + If unsure, say no. diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile new file mode 100644 index 0000000..1e2d83f --- /dev/null +++ b/drivers/reset/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_RESET_CONTROLLER) += core.o diff --git a/drivers/reset/core.c b/drivers/reset/core.c new file mode 100644 index 0000000..468f831 --- /dev/null +++ b/drivers/reset/core.c @@ -0,0 +1,238 @@ +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_MUTEX(reset_controller_list_mutex); +static LIST_HEAD(reset_controller_list); + +/** + * struct reset_control - a reset control + * + * @id: ID of the reset controller in the reset + * controller device + */ +struct reset_control { + struct reset_controller_dev *rcdev; + unsigned int id; +}; + +/** + * reset_controller_register - register a reset controller device + * + * @rcdev: a pointer to struct reset_controller_dev + */ +int reset_controller_register(struct reset_controller_dev *rcdev) +{ + mutex_lock(&reset_controller_list_mutex); + list_add(&rcdev->list, &reset_controller_list); + mutex_unlock(&reset_controller_list_mutex); + + return 0; +} + +/** + * reset_controller_unregister - unregister a reset controller device + * + * @rcdev: a pointer to struct reset_controller_dev + */ +void reset_controller_unregister(struct reset_controller_dev *rcdev) +{ + mutex_lock(&reset_controller_list_mutex); + list_del(&rcdev->list); + mutex_unlock(&reset_controller_list_mutex); +} + +/** + * reset_control_reset - reset the controlled device + * @rstc: reset controller + */ +int reset_control_reset(struct reset_control *rstc) +{ + if (rstc->rcdev->ops->reset) + return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); + + return -ENOSYS; +} +EXPORT_SYMBOL_GPL(reset_control_reset); + +/** + * reset_control_assert - asserts the reset line + * @rstc: reset controller + */ +int reset_control_assert(struct reset_control *rstc) +{ + if (rstc->rcdev->ops->assert) + return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); + + return -ENOSYS; +} +EXPORT_SYMBOL_GPL(reset_control_assert); + +/** + * reset_control_deassert - deasserts the reset line + * @rstc: reset controller + */ +int reset_control_deassert(struct reset_control *rstc) +{ + if (rstc->rcdev->ops->deassert) + return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); + + return -ENOSYS; +} +EXPORT_SYMBOL_GPL(reset_control_deassert); + +/** + * reset_control_get - Lookup and obtain a reference to a reset controller. + * @dev: device to be reset by the controller + * @id: reset line name + * + * Returns a struct reset_control or IS_ERR() condition containing errno. + * + * Use of id names is optional. + */ +struct reset_control *reset_control_get(struct device *dev, const char *id) +{ + struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER); + struct reset_controller_dev *r, *rcdev; + struct device_node *rcdev_node; + struct of_phandle_args args; + int rcdev_index; + int ret; + int i; + + if (!dev) + return ERR_PTR(-EINVAL); + + rcdev_node = NULL; + for (i = 0; rcdev_node == NULL; i++) { + ret = of_parse_phandle_with_args(dev->of_node, "resets", + "#reset-cells", i, &args); + if (ret) + return ERR_PTR(ret); + of_node_put(args.np); + if (args.args_count <= 0) + return ERR_PTR(-EINVAL); + + if (id) { + const char *reset_name; + ret = of_property_read_string_index(dev->of_node, + "reset-names", i, + &reset_name); + if (ret) + return ERR_PTR(ret); + if (strcmp(id, reset_name) != 0) + continue; + } + + rcdev_index = args.args[0]; + rcdev_node = args.np; + break; + } + + mutex_lock(&reset_controller_list_mutex); + rcdev = NULL; + list_for_each_entry(r, &reset_controller_list, list) { + if (rcdev_node == r->of_node) { + rcdev = r; + break; + } + } + mutex_unlock(&reset_controller_list_mutex); + + if (!rcdev) + return ERR_PTR(-ENODEV); + + try_module_get(rcdev->owner); + + rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); + if (!rstc) + return ERR_PTR(-ENOMEM); + + rstc->rcdev = rcdev; + rstc->id = rcdev_index; + + return rstc; +} +EXPORT_SYMBOL_GPL(reset_control_get); + +/** + * reset_control_put - free the reset controller + * @reset: reset controller + */ + +void reset_control_put(struct reset_control *rstc) +{ + if (IS_ERR(rstc)) + return; + + module_put(rstc->rcdev->owner); + kfree(rstc); +} +EXPORT_SYMBOL_GPL(reset_control_put); + +static void devm_reset_control_release(struct device *dev, void *res) +{ + reset_control_put(*(struct reset_control **)res); +} + +/** + * devm_reset_control_get - resource managed reset_control_get() + * @dev: device to be reset by the controller + * @id: reset line name + * + * Managed reset_control_get(). For reset controllers returned from this + * function, reset_control_put() is called automatically on driver detach. + * See reset_control_get() for more information. + */ +struct reset_control *devm_reset_control_get(struct device *dev, const char *id) +{ + struct reset_control **ptr, *rstc; + + ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), + GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + rstc = reset_control_get(dev, id); + if (!IS_ERR(rstc)) { + *ptr = rstc; + devres_add(dev, ptr); + } else { + devres_free(ptr); + } + + return rstc; +} +EXPORT_SYMBOL_GPL(devm_reset_control_get); + +/** + * device_reset - find reset controller associated with the device + * and perform reset + * @dev: device to be reset by the controller + * + * Convenience wrapper for reset_control_get() and reset_control_reset(). + * This is useful for the common case of devices with single, dedicated reset + * lines. + */ +int device_reset(struct device *dev) +{ + struct reset_control *rstc; + int ret; + + rstc = reset_control_get(dev, NULL); + if (IS_ERR(rstc)) + return PTR_ERR(rstc); + + ret = reset_control_reset(rstc); + + kfree(rstc); + + return ret; +} +EXPORT_SYMBOL_GPL(device_reset); diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h new file mode 100644 index 0000000..4d38aa3 --- /dev/null +++ b/include/linux/reset-controller.h @@ -0,0 +1,39 @@ +#ifndef _LINUX_RESET_CONTROLLER_H_ +#define _LINUX_RESET_CONTROLLER_H_ + +#include + +struct reset_controller_dev; + +/** + * struct reset_control_ops + * + * @reset: for self-deasserting resets, does all necessary + * things to reset the device + * @assert: manually assert the reset line, if supported + * @deassert: manually deassert the reset line, if supported + */ +struct reset_control_ops { + int (*reset)(struct reset_controller_dev *rcdev, unsigned long id); + int (*assert)(struct reset_controller_dev *rcdev, unsigned long id); + int (*deassert)(struct reset_controller_dev *rcdev, unsigned long id); +}; + +struct module; +struct device_node; + +/** + * struct reset_controller - reset controller entity that might + * provide multiple reset controls + */ +struct reset_controller_dev { + struct reset_control_ops *ops; + struct module *owner; + struct list_head list; + struct device_node *of_node; +}; + +int reset_controller_register(struct reset_controller_dev *rcdev); +void reset_controller_unregister(struct reset_controller_dev *rcdev); + +#endif diff --git a/include/linux/reset.h b/include/linux/reset.h new file mode 100644 index 0000000..c4119c5 --- /dev/null +++ b/include/linux/reset.h @@ -0,0 +1,17 @@ +#ifndef _LINUX_RESET_H_ +#define _LINUX_RESET_H_ + +struct device; +struct reset_control; + +int reset_control_reset(struct reset_control *rstc); +int reset_control_assert(struct reset_control *rstc); +int reset_control_deassert(struct reset_control *rstc); + +struct reset_control *reset_controlr_get(struct device *dev, const char *id); +void reset_control_put(struct reset_control *rstc); +struct reset_control *devm_reset_control_get(struct device *dev, const char *id); + +int device_reset(struct device *dev); + +#endif