[PATCH] watchdog: Add MOXA ART watchdog driver

[Jonas Jensen <jonas.jensen@gmail.com>]

Add watchdog driver for MOXA ART SoCs.

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
---

Notes:
    Applies to next-20130711

 drivers/watchdog/Kconfig      |  10 +++
 drivers/watchdog/Makefile     |   1 +
 drivers/watchdog/moxart_wdt.c | 190 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 201 insertions(+)
 create mode 100644 drivers/watchdog/moxart_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 362085d..6883aab 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -382,6 +382,16 @@ config RETU_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called retu_wdt.
 
+config MOXART_WDT
+	tristate "MOXART watchdog"
+	depends on ARCH_MOXART
+	help
+	  Say Y here to include Watchdog timer support for the watchdog
+	  existing on the MOXA ART SoC series platforms.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called moxart_wdt.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 2f26a0b..7cab53a 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
 obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
 obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
 obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
+obj-$(CONFIG_MOXART_WDT) += moxart_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/moxart_wdt.c b/drivers/watchdog/moxart_wdt.c
new file mode 100644
index 0000000..c6c00bf
--- /dev/null
+++ b/drivers/watchdog/moxart_wdt.c
@@ -0,0 +1,190 @@
+/*
+ * MOXA ART SoCs watchdog driver.
+ *
+ * Copyright (C) 2013 Jonas Jensen
+ *
+ * Jonas Jensen <jonas.jensen@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#include <asm/system_misc.h>
+
+#define REG_COUNT			0x4
+#define REG_MODE			0x8
+#define REG_ENABLE			0xC
+
+struct moxart_wdt_dev {
+	struct watchdog_device wdt_dev;
+	void __iomem *wdt_base;
+};
+
+static struct moxart_wdt_dev *moxart_wdt;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+static int heartbeat;
+static unsigned int clock_frequency;
+static unsigned int max_timeout;
+
+static void moxart_wdt_restart(enum reboot_mode reboot_mode, const char *cmd)
+{
+	writel(1, moxart_wdt->wdt_base + REG_COUNT);
+	writel(0x5ab9, moxart_wdt->wdt_base + REG_MODE);
+	writel(0x03, moxart_wdt->wdt_base + REG_ENABLE);
+}
+
+static int moxart_wdt_stop(struct watchdog_device *wdt_dev)
+{
+	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
+	void __iomem *wdt_base = moxart_wdt->wdt_base;
+
+	writel(0, wdt_base + REG_ENABLE);
+
+	return 0;
+}
+
+static int moxart_wdt_start(struct watchdog_device *wdt_dev)
+{
+	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
+	void __iomem *wdt_base = moxart_wdt->wdt_base;
+
+	writel(clock_frequency * moxart_wdt->wdt_dev.timeout,
+	       wdt_base + REG_COUNT);
+	writel(0x5ab9, wdt_base + REG_MODE);
+	writel(0x03, wdt_base + REG_ENABLE);
+
+	return 0;
+}
+
+static int moxart_wdt_ping(struct watchdog_device *wdt_dev)
+{
+	moxart_wdt_start(wdt_dev);
+	return 0;
+}
+
+static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev,
+				  unsigned int timeout)
+{
+	dev_dbg(wdt_dev->dev, "%s: timeout=%u\n", __func__, timeout);
+
+	if (timeout > max_timeout)
+		return -EINVAL;
+
+	moxart_wdt->wdt_dev.timeout = timeout;
+
+	return 0;
+}
+
+static const struct watchdog_info moxart_wdt_info = {
+	.identity       = "moxart-wdt",
+	.options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+			  WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops moxart_wdt_ops = {
+	.owner          = THIS_MODULE,
+	.start          = moxart_wdt_start,
+	.stop           = moxart_wdt_stop,
+	.ping           = moxart_wdt_ping,
+	.set_timeout    = moxart_wdt_set_timeout,
+};
+
+static int moxart_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	struct resource *res;
+	struct clk *clk;
+	int err;
+
+	moxart_wdt = devm_kzalloc(&pdev->dev, sizeof(*moxart_wdt), GFP_KERNEL);
+	if (!moxart_wdt)
+		return -EINVAL;
+
+	platform_set_drvdata(pdev, moxart_wdt);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	moxart_wdt->wdt_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(moxart_wdt->wdt_base))
+		return PTR_ERR(moxart_wdt->wdt_base);
+
+	arm_pm_restart = moxart_wdt_restart;
+
+	clk = of_clk_get(node, 0);
+	if (IS_ERR(clk)) {
+		pr_err("%s: of_clk_get failed\n", __func__);
+		return PTR_ERR(clk);
+	}
+
+	clock_frequency = clk_get_rate(clk);
+
+	max_timeout = UINT_MAX / clock_frequency;
+
+	moxart_wdt->wdt_dev.info = &moxart_wdt_info;
+	moxart_wdt->wdt_dev.ops = &moxart_wdt_ops;
+	moxart_wdt->wdt_dev.timeout = max_timeout;
+	moxart_wdt->wdt_dev.min_timeout = 1;
+	moxart_wdt->wdt_dev.max_timeout = max_timeout;
+	moxart_wdt->wdt_dev.parent = &pdev->dev;
+
+	watchdog_init_timeout(&moxart_wdt->wdt_dev, heartbeat, &pdev->dev);
+	watchdog_set_nowayout(&moxart_wdt->wdt_dev, nowayout);
+
+	watchdog_set_drvdata(&moxart_wdt->wdt_dev, moxart_wdt);
+
+	err = watchdog_register_device(&moxart_wdt->wdt_dev);
+	if (unlikely(err))
+		return err;
+
+	dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n",
+		 moxart_wdt->wdt_dev.timeout, nowayout);
+
+	return 0;
+}
+
+static int moxart_wdt_remove(struct platform_device *pdev)
+{
+	struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev);
+
+	watchdog_unregister_device(&moxart_wdt->wdt_dev);
+	watchdog_set_drvdata(&moxart_wdt->wdt_dev, NULL);
+
+	return 0;
+}
+
+static const struct of_device_id moxart_watchdog_match[] = {
+	{ .compatible = "moxa,moxart-watchdog" },
+	{ },
+};
+
+static struct platform_driver moxart_wdt_driver = {
+	.probe      = moxart_wdt_probe,
+	.remove     = moxart_wdt_remove,
+	.driver     = {
+		.name		= "moxart-watchdog",
+		.owner		= THIS_MODULE,
+		.of_match_table	= moxart_watchdog_match,
+	},
+};
+module_platform_driver(moxart_wdt_driver);
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");
+
+MODULE_DESCRIPTION("MOXART watchdog driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
-- 
1.8.2.1