This patch adds a watchdog driver for devices controlled through GPIO,
(Analog Devices ADM706, for example). Driver written for DT-based systems
only. No description for Documentation/devicetree yet.
Comments are welcome.
Signed-off-by: Alexander Shiyan <shc_work@xxxxxxx>
---
drivers/watchdog/Kconfig | 8 +++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/gpio_wdt.c | 121 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 130 insertions(+)
create mode 100644 drivers/watchdog/gpio_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 3eb1cc6..811030c 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -87,6 +87,14 @@ config DA9055_WATCHDOG
This driver can also be built as a module. If so, the module
will be called da9055_wdt.
+config GPIO_WATCHDOG
+ tristate "Watchdog device controlled through GPIO-line"
+ depends on OF_GPIO
+ select WATCHDOG_CORE
+ help
+ If you say yes here you get support for watchdog device
+ controlled through GPIO-line.
+
config WM831X_WATCHDOG
tristate "WM831x watchdog"
depends on MFD_WM831X
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index ec26899..ca85cbd 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -168,6 +168,7 @@ obj-$(CONFIG_XEN_WDT) += xen_wdt.o
# Architecture Independent
obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o
obj-$(CONFIG_DA9055_WATCHDOG) += da9055_wdt.o
+obj-$(CONFIG_GPIO_WATCHDOG) += gpio_wdt.o
obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o
diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c
new file mode 100644
index 0000000..ee4ffba
--- /dev/null
+++ b/drivers/watchdog/gpio_wdt.c
@@ -0,0 +1,121 @@
+/*
+ * Driver for watchdog device controlled through GPIO-line
+ *
+ * Author: 2013, Alexander Shiyan <shc_work@xxxxxxx>
+ *
+ * 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 <linux/err.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+struct gpio_wdt_priv {
+ int gpio;
+ struct watchdog_device wdd;
+};
+
+static int gpio_wdt_ping(struct watchdog_device *wdd)
+{
+ struct gpio_wdt_priv *priv =
+ container_of(wdd, struct gpio_wdt_priv, wdd);
+
+ /* Toggle output */
+ gpio_set_value(priv->gpio, !gpio_get_value(priv->gpio));
+
+ return 0;
+}
+
+static int gpio_wdt_start(struct watchdog_device *wdd)
+{
+ struct gpio_wdt_priv *priv =
+ container_of(wdd, struct gpio_wdt_priv, wdd);
+
+ /* Enable watchdog by set output to logic level */
+ gpio_direction_output(priv->gpio, 0);
+ gpio_set_value(priv->gpio, 1);
+
+ return 0;
+}
+
+static int gpio_wdt_stop(struct watchdog_device *wdd)
+{
+ struct gpio_wdt_priv *priv =
+ container_of(wdd, struct gpio_wdt_priv, wdd);
+
+ /* Disable watchdog by set output to tristate */
+ return gpio_direction_input(priv->gpio);
+}
+
+static const struct watchdog_info gpio_wdt_ident = {
+ .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+ .identity = "GPIO Watchdog",
+};
+
+static const struct watchdog_ops gpio_wdt_ops = {
+ .owner = THIS_MODULE,
+ .ping = gpio_wdt_ping,
+ .start = gpio_wdt_start,
+ .stop = gpio_wdt_stop,
+};
+
+static int gpio_wdt_probe(struct platform_device *pdev)
+{
+ struct gpio_wdt_priv *priv;
+ bool nowayout;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->gpio = of_get_gpio(pdev->dev.of_node, 0);
+ if (priv->gpio < 0)
+ return priv->gpio;
+
+ platform_set_drvdata(pdev, priv);
+
+ priv->wdd.info = &gpio_wdt_ident;
+ priv->wdd.ops = &gpio_wdt_ops;
+
+ nowayout = of_property_read_bool(pdev->dev.of_node, "wdt,nowayout");
+ if (!nowayout)
+ nowayout = WATCHDOG_NOWAYOUT;
+ watchdog_set_nowayout(&priv->wdd, nowayout);
+
+ return watchdog_register_device(&priv->wdd);
+}
+
+static int gpio_wdt_remove(struct platform_device *pdev)
+{
+ struct gpio_wdt_priv *priv = platform_get_drvdata(pdev);
+
+ watchdog_unregister_device(&priv->wdd);
+
+ return 0;
+}
+
+static const struct of_device_id gpio_wdt_dt_ids[] = {
+ { .compatible = "linux,wdt-gpio", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids);
+
+static struct platform_driver gpio_wdt_driver = {
+ .driver = {
+ .name = "gpio-wdt",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(gpio_wdt_dt_ids),
+ },
+ .probe = gpio_wdt_probe,
+ .remove = gpio_wdt_remove,
+};
+module_platform_driver(gpio_wdt_driver);
+
+MODULE_AUTHOR("Alexander Shiyan <shc_work@xxxxxxx>");
+MODULE_DESCRIPTION("GPIO Watchdog");
+MODULE_LICENSE("GPL");
--
1.8.1.5
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