From patchwork Mon Apr 14 08:21:49 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philipp Zabel X-Patchwork-Id: 3978141 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id DA32D9F387 for ; Mon, 14 Apr 2014 08:24:50 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C144B201DE for ; Mon, 14 Apr 2014 08:24:49 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4185D20121 for ; Mon, 14 Apr 2014 08:24:45 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WZcA5-00022Q-RK; Mon, 14 Apr 2014 08:22:41 +0000 Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WZc9u-00014d-6x for linux-arm-kernel@lists.infradead.org; Mon, 14 Apr 2014 08:22:31 +0000 Received: from paszta.hi.pengutronix.de ([10.1.0.120] helo=paszta.pengutronix.de.) by metis.ext.pengutronix.de with esmtp (Exim 4.72) (envelope-from ) id 1WZc9Q-0002JQ-4u; Mon, 14 Apr 2014 10:22:00 +0200 From: Philipp Zabel To: linux-kernel@vger.kernel.org, Arnd Bergmann Arnd Bergmann Subject: [PATCH v4 2/2] reset: Add GPIO support to reset controller framework Date: Mon, 14 Apr 2014 10:21:49 +0200 Message-Id: <1397463709-19405-2-git-send-email-p.zabel@pengutronix.de> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1397463709-19405-1-git-send-email-p.zabel@pengutronix.de> References: <1397463709-19405-1-git-send-email-p.zabel@pengutronix.de> X-SA-Exim-Connect-IP: 10.1.0.120 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-20140414_012230_891180_68B5688E X-CRM114-Status: GOOD ( 24.08 ) X-Spam-Score: -1.0 (-) Cc: Mark Rutland , devicetree@vger.kernel.org, Philipp Zabel , Stephen Warren , kernel@pengutronix.de, Maxime Ripard , linux-arm-kernel@lists.infradead.org, Roger Quadros X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.9 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This adds support for GPIO controlled reset pins on peripheral ICs to the reset controller framework. Currently there is no support for specifying a delay between assertion and de-assertion of the reset signal, so this has to be handled by the drivers. Signed-off-by: Philipp Zabel --- Changes since v3: - Rebased onto v3.15-rc1 - Turned gpiod_get error into debug message, we don't want this to trigger for optional resets if no GPIO is given. --- drivers/reset/Kconfig | 17 ++++++ drivers/reset/Makefile | 9 ++- drivers/reset/core.c | 29 +++++----- drivers/reset/gpio-reset.c | 137 +++++++++++++++++++++++++++++++++++++++++++++ drivers/reset/reset-core.h | 48 ++++++++++++++++ 5 files changed, 225 insertions(+), 15 deletions(-) create mode 100644 drivers/reset/gpio-reset.c create mode 100644 drivers/reset/reset-core.h diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig index 0615f50..26a1d24 100644 --- a/drivers/reset/Kconfig +++ b/drivers/reset/Kconfig @@ -10,6 +10,23 @@ menuconfig RESET_CONTROLLER This framework is designed to abstract reset handling of devices via GPIOs or SoC-internal reset controller modules. + If the device tree contains any resets or reset-gpio properties, + this probably should be enabled. + If unsure, say no. +if RESET_CONTROLLER + +menuconfig RESET_GPIO + bool "GPIO Reset Support" + depends on GPIOLIB + default y if GPIOLIB + help + GPIO Reset Controller support. + + This option lets the reset controller framework handle reset lines + connected to GPIOs. + +endif + source "drivers/reset/sti/Kconfig" diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile index 4f60caf..44c96b3 100644 --- a/drivers/reset/Makefile +++ b/drivers/reset/Makefile @@ -1,3 +1,10 @@ -obj-$(CONFIG_RESET_CONTROLLER) += core.o +reset-core-objs := core.o + +obj-$(CONFIG_RESET_CONTROLLER) += reset-core.o + +ifeq ($(CONFIG_RESET_GPIO),y) + reset-core-objs += gpio-reset.o +endif + obj-$(CONFIG_ARCH_SUNXI) += reset-sunxi.o obj-$(CONFIG_ARCH_STI) += sti/ diff --git a/drivers/reset/core.c b/drivers/reset/core.c index baeaf82..6bfd2d2 100644 --- a/drivers/reset/core.c +++ b/drivers/reset/core.c @@ -18,23 +18,12 @@ #include #include +#include "reset-core.h" + static DEFINE_MUTEX(reset_controller_list_mutex); static LIST_HEAD(reset_controller_list); /** - * struct reset_control - a reset control - * @rcdev: a pointer to the reset controller device - * this reset control belongs to - * @id: ID of the reset controller in the reset - * controller device - */ -struct reset_control { - struct reset_controller_dev *rcdev; - struct device *dev; - unsigned int id; -}; - -/** * of_reset_simple_xlate - translate reset_spec to the reset line number * @rcdev: a pointer to the reset controller device * @reset_spec: reset line specifier as found in the device tree @@ -149,6 +138,8 @@ struct reset_control *of_reset_control_get(struct device_node *node, "reset-names", id); ret = of_parse_phandle_with_args(node, "resets", "#reset-cells", index, &args); + if (index == -EINVAL) + return ERR_PTR(-ENOENT); if (ret) return ERR_PTR(ret); @@ -209,6 +200,13 @@ struct reset_control *reset_control_get(struct device *dev, const char *id) if (!IS_ERR(rstc)) rstc->dev = dev; + /* + * If there is no dedicated reset controller device, check if we have + * a reset line controlled by a GPIO instead. + */ + if (PTR_ERR(rstc) == -ENOENT) + return gpio_reset_control_get(dev, id); + return rstc; } EXPORT_SYMBOL_GPL(reset_control_get); @@ -223,7 +221,10 @@ void reset_control_put(struct reset_control *rstc) if (IS_ERR(rstc)) return; - module_put(rstc->rcdev->owner); + if (reset_control_is_gpio(rstc)) + gpio_reset_control_put(rstc); + else + module_put(rstc->rcdev->owner); kfree(rstc); } EXPORT_SYMBOL_GPL(reset_control_put); diff --git a/drivers/reset/gpio-reset.c b/drivers/reset/gpio-reset.c new file mode 100644 index 0000000..4b12136 --- /dev/null +++ b/drivers/reset/gpio-reset.c @@ -0,0 +1,137 @@ +/* + * GPIO Reset Controller + * + * Copyright 2013 Philipp Zabel, Pengutronix + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ +#include +#include +#include +#include +#include +#include +#include + +#include "reset-core.h" + +/* + * Global GPIO reset controller + */ +static struct reset_controller_dev *gpio_rcdev; + +static int gpio_reset_set(struct reset_controller_dev *rcdev, + unsigned int gpio, int asserted) +{ + struct gpio_desc *gpiod = gpio_to_desc(gpio); + + if (!gpiod) + return -EINVAL; + + gpiod_set_value_cansleep(gpiod, asserted); + + return 0; +} + +static int gpio_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return gpio_reset_set(rcdev, id, 1); +} + +static int gpio_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return gpio_reset_set(rcdev, id, 0); +} + +static struct reset_control_ops gpio_reset_ops = { + .assert = gpio_reset_assert, + .deassert = gpio_reset_deassert, +}; + +struct reset_controller_dev *reset_get_gpio_rcdev(void) +{ + if (gpio_rcdev) + return gpio_rcdev; + + gpio_rcdev = kzalloc(sizeof(*gpio_rcdev), GFP_KERNEL); + if (!gpio_rcdev) + return NULL; + + gpio_rcdev->owner = THIS_MODULE; + gpio_rcdev->ops = &gpio_reset_ops; + + reset_controller_register(gpio_rcdev); + + return gpio_rcdev; +} + +struct reset_control *gpio_reset_control_get(struct device *dev, const char *id) +{ + const char *assert_prop = "reset-boot-asserted"; + const char *gpio_con_id = "reset"; + struct reset_controller_dev *rcdev; + struct reset_control *rstc; + struct gpio_desc *gpiod; + char scratch[48]; + bool asserted; + int ret; + + if (id) { + snprintf(scratch, 48, "%s-reset-boot-asserted", id); + assert_prop = scratch; + } + + asserted = of_property_read_bool(dev->of_node, assert_prop); + + if (id) { + snprintf(scratch, 48, "%s-reset", id); + gpio_con_id = scratch; + } + + gpiod = gpiod_get(dev, gpio_con_id); + if (IS_ERR(gpiod)) { + dev_dbg(dev, "Failed to get GPIO reset: %ld\n", PTR_ERR(gpiod)); + return ERR_CAST(gpiod); + } + + ret = gpiod_direction_output(gpiod, asserted); + if (ret < 0) + goto err_put; + + ret = -ENOMEM; + rcdev = reset_get_gpio_rcdev(); + if (!rcdev) + goto err_put; + + rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); + if (!rstc) + goto err_put; + + rstc->dev = dev; + rstc->rcdev = rcdev; + rstc->id = desc_to_gpio(gpiod); + + return rstc; + +err_put: + gpiod_put(gpiod); + return ERR_PTR(ret); +} + +bool reset_control_is_gpio(struct reset_control *rstc) +{ + return rstc->rcdev == gpio_rcdev; +} + +void gpio_reset_control_put(struct reset_control *rstc) +{ + struct gpio_desc *gpiod = gpio_to_desc(rstc->id); + + if (gpiod) + gpiod_put(gpiod); +} diff --git a/drivers/reset/reset-core.h b/drivers/reset/reset-core.h new file mode 100644 index 0000000..ef50100 --- /dev/null +++ b/drivers/reset/reset-core.h @@ -0,0 +1,48 @@ +/* + * Reset Controller framework + * + * Copyright 2013 Philipp Zabel, Pengutronix + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#ifndef __RESET_CORE_H__ +#define __RESET_CORE_H__ + +/** + * struct reset_control - a reset control + * @rcdev: a pointer to the reset controller device + * this reset control belongs to + * @id: ID of the reset controller in the reset + * controller device + */ +struct reset_control { + struct reset_controller_dev *rcdev; + struct device *dev; + unsigned int id; +}; + +#if IS_ENABLED(CONFIG_RESET_GPIO) +struct reset_control *gpio_reset_control_get(struct device *dev, + const char *id); +bool reset_control_is_gpio(struct reset_control *rstc); +void gpio_reset_control_put(struct reset_control *rstc); +#else +static inline struct reset_control *gpio_reset_control_get(struct device *dev, + const char *id) +{ + return -ENOSYS; +} + +static inline bool reset_control_is_gpio(struct reset_control *rstc) +{ + return false; +} + +static inline void gpio_reset_control_put(struct reset_control *rstc) { } +#endif + +#endif