[PATCH 2/2] watchdog: add support for Sigma Designs SMP86xx

[Mans Rullgard]

This adds support for the Sigma Designs SMP86xx family built-in
watchdog.

Signed-off-by: Mans Rullgard <mans@xxxxxxxxx>
---
 drivers/watchdog/Kconfig      |   7 ++
 drivers/watchdog/Makefile     |   1 +
 drivers/watchdog/tangox_wdt.c | 185 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 193 insertions(+)
 create mode 100644 drivers/watchdog/tangox_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 79e1aa1..0ed5ee8 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1337,6 +1337,13 @@ config RALINK_WDT
 	help
 	  Hardware driver for the Ralink SoC Watchdog Timer.
 
+config TANGOX_WDT
+	tristate "SMP86xx watchdog"
+	select WATCHDOG_CORE
+	depends on ARCH_TANGOX
+	help
+	  Watchdog driver for Sigma Designs SMP86xx.
+
 # PARISC Architecture
 
 # POWERPC Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 0c616e3..ed00796 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -148,6 +148,7 @@ octeon-wdt-y := octeon-wdt-main.o octeon-wdt-nmi.o
 obj-$(CONFIG_LANTIQ_WDT) += lantiq_wdt.o
 obj-$(CONFIG_RALINK_WDT) += rt2880_wdt.o
 obj-$(CONFIG_IMGPDC_WDT) += imgpdc_wdt.o
+obj-$(CONFIG_TANGOX_WDT) += tangox_wdt.o
 
 # PARISC Architecture
 
diff --git a/drivers/watchdog/tangox_wdt.c b/drivers/watchdog/tangox_wdt.c
new file mode 100644
index 0000000..305759f
--- /dev/null
+++ b/drivers/watchdog/tangox_wdt.c
@@ -0,0 +1,185 @@
+/*
+ *  Copyright (C) 2014, Mans Rullgard <mans@xxxxxxxxx>
+ *  SMP86xx Watchdog driver
+ *
+ *  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/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/notifier.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#define DEFAULT_TIMEOUT	30
+#define MAX_TIMEOUT	120
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+		 "Watchdog cannot be stopped once started (default="
+		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static unsigned int timeout = DEFAULT_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(watchdog_timeout, "Watchdog timeout");
+
+#define WD_COUNTER	0
+#define WD_CONFIG	4
+
+struct tangox_wdt_device {
+	struct watchdog_device wdt;
+	void __iomem *base;
+	unsigned int timeout;
+	struct clk *clk;
+	struct notifier_block restart;
+};
+
+static int tangox_wdt_ping(struct watchdog_device *wdt)
+{
+	struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
+
+	writel(dev->timeout, dev->base + WD_COUNTER);
+
+	return 0;
+}
+
+static int tangox_wdt_set_timeout(struct watchdog_device *wdt,
+				  unsigned int new_timeout)
+{
+	struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
+
+	wdt->timeout = new_timeout;
+	dev->timeout = 1 + new_timeout * clk_get_rate(dev->clk);
+
+	tangox_wdt_ping(wdt);
+
+	return 0;
+}
+
+static int tangox_wdt_start(struct watchdog_device *wdt)
+{
+	return tangox_wdt_set_timeout(wdt, wdt->timeout);
+}
+
+static int tangox_wdt_stop(struct watchdog_device *wdt)
+{
+	struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
+
+	writel(0, dev->base + WD_COUNTER);
+
+	return 0;
+}
+
+static const struct watchdog_info tangox_wdt_info = {
+	.options  = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "tangox watchdog",
+};
+
+static const struct watchdog_ops tangox_wdt_ops = {
+	.start		= tangox_wdt_start,
+	.stop		= tangox_wdt_stop,
+	.ping		= tangox_wdt_ping,
+	.set_timeout	= tangox_wdt_set_timeout,
+};
+
+static int tangox_wdt_restart(struct notifier_block *nb, unsigned long action,
+			      void *data)
+{
+	struct tangox_wdt_device *dev =
+		container_of(nb, struct tangox_wdt_device, restart);
+
+	writel(1, dev->base + WD_COUNTER);
+
+	return NOTIFY_DONE;
+}
+
+static int tangox_wdt_probe(struct platform_device *pdev)
+{
+	struct tangox_wdt_device *dev;
+	struct resource *res;
+	int err;
+
+	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->wdt.parent = &pdev->dev;
+	dev->wdt.info = &tangox_wdt_info;
+	dev->wdt.ops = &tangox_wdt_ops;
+	dev->wdt.timeout = timeout;
+	dev->wdt.min_timeout = 1;
+	dev->wdt.max_timeout = MAX_TIMEOUT;
+	watchdog_set_nowayout(&dev->wdt, nowayout);
+	watchdog_set_drvdata(&dev->wdt, dev);
+
+	dev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dev->clk))
+		return PTR_ERR(dev->clk);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
+
+	dev->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(dev->base))
+		return PTR_ERR(dev->base);
+
+	writel(0, dev->base + WD_COUNTER);
+	writel(1, dev->base + WD_CONFIG);
+
+	err = watchdog_register_device(&dev->wdt);
+	if (err)
+		return err;
+
+	platform_set_drvdata(pdev, dev);
+
+	dev->restart.notifier_call = tangox_wdt_restart;
+	dev->restart.priority = 128;
+	err = register_restart_handler(&dev->restart);
+	if (err)
+		dev_err(&pdev->dev, "failed to register restart handler\n");
+
+	dev_info(dev->wdt.dev, "SMP86xx watchdog registered\n");
+
+	return 0;
+}
+
+static int tangox_wdt_remove(struct platform_device *pdev)
+{
+	struct tangox_wdt_device *dev = platform_get_drvdata(pdev);
+
+	tangox_wdt_stop(&dev->wdt);
+	unregister_restart_handler(&dev->restart);
+	watchdog_unregister_device(&dev->wdt);
+
+	return 0;
+}
+
+static const struct of_device_id tangox_wdt_dt_ids[] = {
+	{ .compatible = "sigma,smp8642-wdt" },
+	{ }
+};
+
+static struct platform_driver tangox_wdt_driver = {
+	.probe	= tangox_wdt_probe,
+	.remove	= tangox_wdt_remove,
+	.driver	= {
+		.name		= "tangox-wdt",
+		.of_match_table	= tangox_wdt_dt_ids,
+	},
+};
+
+module_platform_driver(tangox_wdt_driver);
+
+MODULE_AUTHOR("Mans Rullgard <mans@xxxxxxxxx>");
+MODULE_DESCRIPTION("SMP86xx Watchdog driver");
+MODULE_LICENSE("GPL");
-- 
2.6.2

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