From patchwork Tue Jul 16 14:33:22 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philipp Zabel X-Patchwork-Id: 2828151 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 31739C0AB2 for ; Tue, 16 Jul 2013 14:34:07 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CA123201C6 for ; Tue, 16 Jul 2013 14:34:05 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E85FC201C2 for ; Tue, 16 Jul 2013 14:34:03 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Uz6KF-0003uB-B9; Tue, 16 Jul 2013 14:33:59 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Uz6KD-0006Uy-2O; Tue, 16 Jul 2013 14:33:57 +0000 Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Uz6K8-0006U6-Vf for linux-arm-kernel@lists.infradead.org; Tue, 16 Jul 2013 14:33:54 +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 1Uz6Jl-0003k0-RP; Tue, 16 Jul 2013 16:33:29 +0200 From: Philipp Zabel To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v9] reset: Add driver for gpio-controlled reset pins Date: Tue, 16 Jul 2013 16:33:22 +0200 Message-Id: <1373985202-16353-1-git-send-email-p.zabel@pengutronix.de> X-Mailer: git-send-email 1.8.3.2 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-20130716_103353_595830_CCCABEA8 X-CRM114-Status: GOOD ( 26.93 ) X-Spam-Score: -2.3 (--) Cc: Marek Vasut , Fabio Estevam , Mike Turquette , Philipp Zabel , Arnd Bergmann , Len Brown , Sascha Hauer , Stephen Warren , "Rafael J. Wysocki" , Pavel Machek , Olof Johansson , Shawn Guo , devicetree-discuss@lists.ozlabs.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=-4.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, 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 driver implements a reset controller device that toggle a gpio connected to a reset pin of a peripheral IC. The delay between assertion and de-assertion of the reset signal can be configured via device tree. Signed-off-by: Philipp Zabel Reviewed-by: Stephen Warren --- Changes since v8, as suggested by Shawn: - added support for I2C gpios via gpio_set_value_cansleep - switched from module_init to arch_initcall to avoid unnecessary probe deferral of subsys_initcall drivers like gpio-pca953x. --- .../devicetree/bindings/reset/gpio-reset.txt | 35 ++++ drivers/reset/Kconfig | 11 ++ drivers/reset/Makefile | 1 + drivers/reset/gpio-reset.c | 188 +++++++++++++++++++++ 4 files changed, 235 insertions(+) create mode 100644 Documentation/devicetree/bindings/reset/gpio-reset.txt create mode 100644 drivers/reset/gpio-reset.c diff --git a/Documentation/devicetree/bindings/reset/gpio-reset.txt b/Documentation/devicetree/bindings/reset/gpio-reset.txt new file mode 100644 index 0000000..bca5348 --- /dev/null +++ b/Documentation/devicetree/bindings/reset/gpio-reset.txt @@ -0,0 +1,35 @@ +GPIO reset controller +===================== + +A GPIO reset controller controls a single GPIO that is connected to the reset +pin of a peripheral IC. Please also refer to reset.txt in this directory for +common reset controller binding usage. + +Required properties: +- compatible: Should be "gpio-reset" +- reset-gpios: A gpio used as reset line. The gpio specifier for this property + depends on the gpio controller that provides the gpio. +- #reset-cells: 0, see below + +Optional properties: +- reset-delay-us: delay in microseconds. The gpio reset line will be asserted for + this duration to reset. +- initially-in-reset: boolean. If not set, the initial state should be a + deasserted reset line. If this property exists, the + reset line should be kept in reset. + +example: + +sii902x_reset: gpio-reset { + compatible = "gpio-reset"; + reset-gpios = <&gpio5 0 GPIO_ACTIVE_LOW>; + reset-delay-us = <10000>; + initially-in-reset; + #reset-cells = <0>; +}; + +/* Device with nRESET pin connected to GPIO5_0 */ +sii902x@39 { + /* ... */ + resets = <&sii902x_reset>; /* active-low GPIO5_0, 10 ms delay */ +}; diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig index c9d04f7..1a862df 100644 --- a/drivers/reset/Kconfig +++ b/drivers/reset/Kconfig @@ -11,3 +11,14 @@ menuconfig RESET_CONTROLLER via GPIOs or SoC-internal reset controller modules. If unsure, say no. + +if RESET_CONTROLLER + +config RESET_GPIO + tristate "GPIO reset controller support" + depends on GPIOLIB && OF + help + This driver provides support for reset lines that are controlled + directly by GPIOs. + +endif diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile index 1e2d83f..b854f20 100644 --- a/drivers/reset/Makefile +++ b/drivers/reset/Makefile @@ -1 +1,2 @@ obj-$(CONFIG_RESET_CONTROLLER) += core.o +obj-$(CONFIG_RESET_GPIO) += gpio-reset.o diff --git a/drivers/reset/gpio-reset.c b/drivers/reset/gpio-reset.c new file mode 100644 index 0000000..e9c15c0 --- /dev/null +++ b/drivers/reset/gpio-reset.c @@ -0,0 +1,188 @@ +/* + * GPIO Reset Controller driver + * + * 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 + +struct gpio_reset_data { + struct reset_controller_dev rcdev; + unsigned int gpio; + bool active_low; + s32 delay_us; +}; + +static void gpio_reset_set(struct reset_controller_dev *rcdev, int asserted) +{ + struct gpio_reset_data *drvdata = container_of(rcdev, + struct gpio_reset_data, rcdev); + int value = asserted; + + if (drvdata->active_low) + value = !value; + + gpio_set_value(drvdata->gpio, value); + if (gpio_cansleep(drvdata->gpio)) + gpio_set_value_cansleep(drvdata->gpio, value); + else + gpio_set_value(drvdata->gpio, value); +} + +static int gpio_reset(struct reset_controller_dev *rcdev, unsigned long id) +{ + struct gpio_reset_data *drvdata = container_of(rcdev, + struct gpio_reset_data, rcdev); + + if (drvdata->delay_us < 0) + return -ENOSYS; + + gpio_reset_set(rcdev, 1); + udelay(drvdata->delay_us); + gpio_reset_set(rcdev, 0); + + return 0; +} + +static int gpio_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + gpio_reset_set(rcdev, 1); + + return 0; +} + +static int gpio_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + gpio_reset_set(rcdev, 0); + + return 0; +} + +static struct reset_control_ops gpio_reset_ops = { + .reset = gpio_reset, + .assert = gpio_reset_assert, + .deassert = gpio_reset_deassert, +}; + +static int of_gpio_reset_xlate(struct reset_controller_dev *rcdev, + const struct of_phandle_args *reset_spec) +{ + if (WARN_ON(reset_spec->args_count != 0)) + return -EINVAL; + + return 0; +} + +static int gpio_reset_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct gpio_reset_data *drvdata; + enum of_gpio_flags flags; + unsigned long gpio_flags; + bool initially_in_reset; + int ret; + + drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL); + if (drvdata == NULL) + return -ENOMEM; + + if (of_gpio_named_count(np, "reset-gpios") != 1) { + dev_err(&pdev->dev, + "reset-gpios property missing, or not a single gpio\n"); + return -EINVAL; + } + + drvdata->gpio = of_get_named_gpio_flags(np, "reset-gpios", 0, &flags); + if (drvdata->gpio == -EPROBE_DEFER) { + return drvdata->gpio; + } else if (!gpio_is_valid(drvdata->gpio)) { + dev_err(&pdev->dev, "invalid reset gpio: %d\n", drvdata->gpio); + return drvdata->gpio; + } + + drvdata->active_low = flags & OF_GPIO_ACTIVE_LOW; + + ret = of_property_read_u32(np, "reset-delay-us", &drvdata->delay_us); + if (ret < 0) + drvdata->delay_us = -1; + else if (drvdata->delay_us < 0) + dev_warn(&pdev->dev, "reset delay too high\n"); + + initially_in_reset = of_property_read_bool(np, "initially-in-reset"); + if (drvdata->active_low ^ initially_in_reset) + gpio_flags = GPIOF_OUT_INIT_HIGH; + else + gpio_flags = GPIOF_OUT_INIT_LOW; + + ret = devm_gpio_request_one(&pdev->dev, drvdata->gpio, gpio_flags, NULL); + if (ret < 0) { + dev_err(&pdev->dev, "failed to request gpio %d: %d\n", + drvdata->gpio, ret); + return ret; + } + + platform_set_drvdata(pdev, drvdata); + + drvdata->rcdev.of_node = np; + drvdata->rcdev.owner = THIS_MODULE; + drvdata->rcdev.nr_resets = 1; + drvdata->rcdev.ops = &gpio_reset_ops; + drvdata->rcdev.of_xlate = of_gpio_reset_xlate; + reset_controller_register(&drvdata->rcdev); + + return 0; +} + +static int gpio_reset_remove(struct platform_device *pdev) +{ + struct gpio_reset_data *drvdata = platform_get_drvdata(pdev); + + reset_controller_unregister(&drvdata->rcdev); + + return 0; +} + +static struct of_device_id gpio_reset_dt_ids[] = { + { .compatible = "gpio-reset" }, + { } +}; + +static struct platform_driver gpio_reset_driver = { + .probe = gpio_reset_probe, + .remove = gpio_reset_remove, + .driver = { + .name = "gpio-reset", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(gpio_reset_dt_ids), + }, +}; + +static int __init gpio_reset_init(void) +{ + return platform_driver_register(&gpio_reset_driver); +} +arch_initcall(gpio_reset_init); + +static void __exit gpio_reset_exit(void) +{ + platform_driver_unregister(&gpio_reset_driver); +} +module_exit(gpio_reset_exit); + +MODULE_AUTHOR("Philipp Zabel "); +MODULE_DESCRIPTION("gpio reset controller"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:gpio-reset"); +MODULE_DEVICE_TABLE(of, gpio_reset_dt_ids);