watchdog: add new driver for STMP3xxx and i.MX23/28

Replace the existing STMP3xxx driver because it has enough drawbacks
that a rewrite is apropriate. The new driver is designed to use the
watchdog framework which makes it a lot smaller and avoids open coding
the watchdog API again. It also uses now an explicitly exported function
from the RTC driver to set up its registers (the old driver silently
reused the hopefully(!) already remapped RTC registers). Also, this
driver is mach independent, while the old one depends on a mach replaced
by another one a year ago. Since the user interface is still the
standard watchdog API, users don't need to adapt.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 111 insertions, 0 deletions

diff --git a/drivers/watchdog/stmp3xxx_rtc_wdt.c b/drivers/watchdog/stmp3xxx_rtc_wdt.c
new file mode 100644
index 000000000000..c97e98dcde62
--- /dev/null
+++ b/drivers/watchdog/stmp3xxx_rtc_wdt.c
@@ -0,0 +1,111 @@
+/*
+ * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28
+ *
+ * Author: Wolfram Sang <w.sang@pengutronix.de>
+ *
+ * Copyright (C) 2011-12 Wolfram Sang, Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/stmp3xxx_rtc_wdt.h>
+
+#define WDOG_TICK_RATE 1000 /* 1 kHz clock */
+#define STMP3XXX_DEFAULT_TIMEOUT 19
+#define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE)
+
+static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT;
+module_param(heartbeat, uint, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to "
+		 __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default "
+		 __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT));
+
+static int wdt_start(struct watchdog_device *wdd)
+{
+	struct device *dev = watchdog_get_drvdata(wdd);
+	struct stmp3xxx_wdt_pdata *pdata = dev->platform_data;
+
+	pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE);
+	return 0;
+}
+
+static int wdt_stop(struct watchdog_device *wdd)
+{
+	struct device *dev = watchdog_get_drvdata(wdd);
+	struct stmp3xxx_wdt_pdata *pdata = dev->platform_data;
+
+	pdata->wdt_set_timeout(dev->parent, 0);
+	return 0;
+}
+
+static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout)
+{
+	wdd->timeout = new_timeout;
+	return wdt_start(wdd);
+}
+
+static const struct watchdog_info stmp3xxx_wdt_ident = {
+	.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+	.identity = "STMP3XXX RTC Watchdog",
+};
+
+static const struct watchdog_ops stmp3xxx_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = wdt_start,
+	.stop = wdt_stop,
+	.set_timeout = wdt_set_timeout,
+};
+
+static struct watchdog_device stmp3xxx_wdd = {
+	.info = &stmp3xxx_wdt_ident,
+	.ops = &stmp3xxx_wdt_ops,
+	.min_timeout = 1,
+	.max_timeout = STMP3XXX_MAX_TIMEOUT,
+	.status = WATCHDOG_NOWAYOUT_INIT_STATUS,
+};
+
+static int stmp3xxx_wdt_probe(struct platform_device *pdev)
+{
+	int ret;
+
+	watchdog_set_drvdata(&stmp3xxx_wdd, &pdev->dev);
+
+	stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT);
+
+	ret = watchdog_register_device(&stmp3xxx_wdd);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "cannot register watchdog device\n");
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "initialized watchdog with heartbeat %ds\n",
+			stmp3xxx_wdd.timeout);
+	return 0;
+}
+
+static int stmp3xxx_wdt_remove(struct platform_device *pdev)
+{
+	watchdog_unregister_device(&stmp3xxx_wdd);
+	return 0;
+}
+
+static struct platform_driver stmp3xxx_wdt_driver = {
+	.driver = {
+		.name = "stmp3xxx_rtc_wdt",
+	},
+	.probe = stmp3xxx_wdt_probe,
+	.remove = stmp3xxx_wdt_remove,
+};
+module_platform_driver(stmp3xxx_wdt_driver);
+
+MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);