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authorDavid Riley <davidriley@chromium.org>2014-08-27 12:23:51 -0700
committerSebastian Reichel <sre@kernel.org>2014-09-26 19:51:15 +0200
commit371bb20d6927f204ef5a7887ecddb06b2501c0d9 (patch)
treeddfd58bf6787b7f459d3fde499a4b83c290835cb /drivers/power
parent1670d8569eeb5c5c15776d37b00a2afb5255bf28 (diff)
downloadop-kernel-dev-371bb20d6927f204ef5a7887ecddb06b2501c0d9.zip
op-kernel-dev-371bb20d6927f204ef5a7887ecddb06b2501c0d9.tar.gz
power: Add simple gpio-restart driver
This driver registers a restart handler to set a GPIO line high/low to reset a board based on devicetree bindings. Signed-off-by: David Riley <davidriley@chromium.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Sebastian Reichel <sre@kernel.org>
Diffstat (limited to 'drivers/power')
-rw-r--r--drivers/power/reset/Kconfig8
-rw-r--r--drivers/power/reset/Makefile1
-rw-r--r--drivers/power/reset/gpio-restart.c149
3 files changed, 158 insertions, 0 deletions
diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 88603b6..a178e9c 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -39,6 +39,14 @@ config POWER_RESET_GPIO
If your board needs a GPIO high/low to power down, say Y and
create a binding in your devicetree.
+config POWER_RESET_GPIO_RESTART
+ bool "GPIO restart driver"
+ depends on OF_GPIO && POWER_RESET
+ help
+ This driver supports restarting your board via a GPIO line.
+ If your board needs a GPIO high/low to restart, say Y and
+ create a binding in your devicetree.
+
config POWER_RESET_HISI
bool "Hisilicon power-off driver"
depends on POWER_RESET && ARCH_HISI
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index 06f106b..ab8cd34 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -2,6 +2,7 @@ obj-$(CONFIG_POWER_RESET_AS3722) += as3722-poweroff.o
obj-$(CONFIG_POWER_RESET_AXXIA) += axxia-reset.o
obj-$(CONFIG_POWER_RESET_BRCMSTB) += brcmstb-reboot.o
obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
+obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o
obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o
obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
diff --git a/drivers/power/reset/gpio-restart.c b/drivers/power/reset/gpio-restart.c
new file mode 100644
index 0000000..a76829b
--- /dev/null
+++ b/drivers/power/reset/gpio-restart.c
@@ -0,0 +1,149 @@
+/*
+ * Toggles a GPIO pin to restart a device
+ *
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Based on the gpio-poweroff driver.
+ */
+#include <linux/reboot.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of_platform.h>
+#include <linux/module.h>
+
+struct gpio_restart {
+ struct gpio_desc *reset_gpio;
+ struct notifier_block restart_handler;
+ u32 active_delay_ms;
+ u32 inactive_delay_ms;
+ u32 wait_delay_ms;
+};
+
+static int gpio_restart_notify(struct notifier_block *this,
+ unsigned long mode, void *cmd)
+{
+ struct gpio_restart *gpio_restart =
+ container_of(this, struct gpio_restart, restart_handler);
+
+ /* drive it active, also inactive->active edge */
+ gpiod_direction_output(gpio_restart->reset_gpio, 1);
+ mdelay(gpio_restart->active_delay_ms);
+
+ /* drive inactive, also active->inactive edge */
+ gpiod_set_value(gpio_restart->reset_gpio, 0);
+ mdelay(gpio_restart->inactive_delay_ms);
+
+ /* drive it active, also inactive->active edge */
+ gpiod_set_value(gpio_restart->reset_gpio, 1);
+
+ /* give it some time */
+ mdelay(gpio_restart->wait_delay_ms);
+
+ WARN_ON(1);
+
+ return NOTIFY_DONE;
+}
+
+static int gpio_restart_probe(struct platform_device *pdev)
+{
+ struct gpio_restart *gpio_restart;
+ bool open_source = false;
+ u32 property;
+ int ret;
+
+ gpio_restart = devm_kzalloc(&pdev->dev, sizeof(*gpio_restart),
+ GFP_KERNEL);
+ if (!gpio_restart)
+ return -ENOMEM;
+
+ open_source = of_property_read_bool(pdev->dev.of_node, "open-source");
+
+ gpio_restart->reset_gpio = devm_gpiod_get(&pdev->dev, NULL,
+ open_source ? GPIOD_IN : GPIOD_OUT_LOW);
+ if (IS_ERR(gpio_restart->reset_gpio)) {
+ dev_err(&pdev->dev, "Could net get reset GPIO\n");
+ return PTR_ERR(gpio_restart->reset_gpio);
+ }
+
+ gpio_restart->restart_handler.notifier_call = gpio_restart_notify;
+ gpio_restart->restart_handler.priority = 128;
+ gpio_restart->active_delay_ms = 100;
+ gpio_restart->inactive_delay_ms = 100;
+ gpio_restart->wait_delay_ms = 3000;
+
+ ret = of_property_read_u32(pdev->dev.of_node, "priority", &property);
+ if (!ret) {
+ if (property > 255)
+ dev_err(&pdev->dev, "Invalid priority property: %u\n",
+ property);
+ else
+ gpio_restart->restart_handler.priority = property;
+ }
+
+ of_property_read_u32(pdev->dev.of_node, "active-delay",
+ &gpio_restart->active_delay_ms);
+ of_property_read_u32(pdev->dev.of_node, "inactive-delay",
+ &gpio_restart->inactive_delay_ms);
+ of_property_read_u32(pdev->dev.of_node, "wait-delay",
+ &gpio_restart->wait_delay_ms);
+
+ platform_set_drvdata(pdev, gpio_restart);
+
+ ret = register_restart_handler(&gpio_restart->restart_handler);
+ if (ret) {
+ dev_err(&pdev->dev, "%s: cannot register restart handler, %d\n",
+ __func__, ret);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static int gpio_restart_remove(struct platform_device *pdev)
+{
+ struct gpio_restart *gpio_restart = platform_get_drvdata(pdev);
+ int ret;
+
+ ret = unregister_restart_handler(&gpio_restart->restart_handler);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "%s: cannot unregister restart handler, %d\n",
+ __func__, ret);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id of_gpio_restart_match[] = {
+ { .compatible = "gpio-restart", },
+ {},
+};
+
+static struct platform_driver gpio_restart_driver = {
+ .probe = gpio_restart_probe,
+ .remove = gpio_restart_remove,
+ .driver = {
+ .name = "restart-gpio",
+ .owner = THIS_MODULE,
+ .of_match_table = of_gpio_restart_match,
+ },
+};
+
+module_platform_driver(gpio_restart_driver);
+
+MODULE_AUTHOR("David Riley <davidriley@chromium.org>");
+MODULE_DESCRIPTION("GPIO restart driver");
+MODULE_LICENSE("GPL");
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