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Subject[PATCH v2 2/2] watchdog: add support for Sigma Designs SMP86xx/SMP87xx
Date
This adds support for the Sigma Designs SMP86xx/SMP87xx family built-in
watchdog.

Signed-off-by: Mans Rullgard <mans@mansr.com>
---
Changes:
- combine start and ping functions
- use watchdog_init_timeout()
- calculate max timeout from clock rate
- add get_timeleft callback
- check if already running on startup
- add explanatory comments
- improve kconfig text
---
drivers/watchdog/Kconfig | 10 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/tangox_wdt.c | 213 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 224 insertions(+)
create mode 100644 drivers/watchdog/tangox_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 7a8a6c6..f43ff7a 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -135,6 +135,16 @@ config MENF21BMC_WATCHDOG
This driver can also be built as a module. If so the module
will be called menf21bmc_wdt.

+config TANGOX_WATCHDOG
+ tristate "Sigma Designs SMP86xx/SMP87xx watchdog"
+ select WATCHDOG_CORE
+ depends on ARCH_TANGOX || COMPILE_TEST
+ help
+ Support for the watchdog in Sigma Designs SMP86xx (tango3)
+ and SMP87xx (tango4) family chips.
+
+ This driver can be built as a module. The module name is tangox_wdt.
+
config WM831X_WATCHDOG
tristate "WM831x watchdog"
depends on MFD_WM831X
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 53d4827..46cb387 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -187,6 +187,7 @@ obj-$(CONFIG_DA9055_WATCHDOG) += da9055_wdt.o
obj-$(CONFIG_DA9062_WATCHDOG) += da9062_wdt.o
obj-$(CONFIG_DA9063_WATCHDOG) += da9063_wdt.o
obj-$(CONFIG_GPIO_WATCHDOG) += gpio_wdt.o
+obj-$(CONFIG_TANGOX_WATCHDOG) += tangox_wdt.o
obj-$(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/tangox_wdt.c b/drivers/watchdog/tangox_wdt.c
new file mode 100644
index 0000000..0b458ff
--- /dev/null
+++ b/drivers/watchdog/tangox_wdt.c
@@ -0,0 +1,213 @@
+/*
+ * Copyright (C) 2015 Mans Rullgard <mans@mansr.com>
+ * SMP86xx/SMP87xx 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/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/notifier.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/watchdog.h>
+
+#define DEFAULT_TIMEOUT 30
+
+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;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout");
+
+/*
+ * Counter counts down from programmed value. Reset asserts when
+ * the counter reaches 1.
+ */
+#define WD_COUNTER 0
+
+#define WD_CONFIG 4
+#define WD_CONFIG_XTAL_IN BIT(0)
+#define WD_CONFIG_DISABLE BIT(31)
+
+struct tangox_wdt_device {
+ struct watchdog_device wdt;
+ void __iomem *base;
+ unsigned long clk_rate;
+ struct clk *clk;
+ struct notifier_block restart;
+};
+
+static int tangox_wdt_set_timeout(struct watchdog_device *wdt,
+ unsigned int new_timeout)
+{
+ wdt->timeout = new_timeout;
+
+ return 0;
+}
+
+static int tangox_wdt_start(struct watchdog_device *wdt)
+{
+ struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
+ u32 ticks;
+
+ ticks = 1 + wdt->timeout * dev->clk_rate;
+ writel(ticks, dev->base + WD_COUNTER);
+
+ return 0;
+}
+
+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 unsigned int tangox_wdt_get_timeleft(struct watchdog_device *wdt)
+{
+ struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
+ u32 count;
+
+ count = readl(dev->base + WD_COUNTER);
+
+ if (!count)
+ return 0;
+
+ return (count - 1) / dev->clk_rate;
+}
+
+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,
+ .set_timeout = tangox_wdt_set_timeout,
+ .get_timeleft = tangox_wdt_get_timeleft,
+};
+
+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;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ dev->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(dev->base))
+ return PTR_ERR(dev->base);
+
+ dev->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(dev->clk))
+ return PTR_ERR(dev->clk);
+
+ err = clk_prepare_enable(dev->clk);
+ if (err)
+ return err;
+
+ dev->clk_rate = clk_get_rate(dev->clk);
+
+ dev->wdt.parent = &pdev->dev;
+ dev->wdt.info = &tangox_wdt_info;
+ dev->wdt.ops = &tangox_wdt_ops;
+ dev->wdt.timeout = DEFAULT_TIMEOUT;
+ dev->wdt.min_timeout = 1;
+ dev->wdt.max_timeout = (U32_MAX - 1) / dev->clk_rate;
+
+ watchdog_init_timeout(&dev->wdt, timeout, &pdev->dev);
+ watchdog_set_nowayout(&dev->wdt, nowayout);
+ watchdog_set_drvdata(&dev->wdt, dev);
+
+ writel(WD_CONFIG_XTAL_IN, dev->base + WD_CONFIG);
+
+ /*
+ * Mark as active and restart with configured timeout if
+ * already running.
+ */
+ if (readl(dev->base + WD_COUNTER)) {
+ set_bit(WDOG_ACTIVE, &dev->wdt.status);
+ tangox_wdt_start(&dev->wdt);
+ }
+
+ 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_warn(&pdev->dev, "failed to register restart handler\n");
+
+ dev_info(dev->wdt.dev, "SMP86xx/SMP87xx 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);
+ clk_disable_unprepare(dev->clk);
+
+ 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" },
+ { .compatible = "sigma,smp8759-wdt" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, tangox_wdt_dt_ids);
+
+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@mansr.com>");
+MODULE_DESCRIPTION("SMP86xx/SMP87xx Watchdog driver");
+MODULE_LICENSE("GPL");
--
2.6.3


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