[PATCH 2/2] watchdog: as3722_wdt: support for AMS AS3722

[Bibek Basu]

Add watchdog timer driver for as3722 device.
The timer can be start/stop and set timing through
watchdog subsystem callbacks.

Change-Id: I5e252fd762764afaa1598cd98fed91864dc23d8d
Signed-off-by: Bibek Basu <bbasu@xxxxxxxxxx>
---
 drivers/watchdog/Kconfig      |   9 ++
 drivers/watchdog/Makefile     |   1 +
 drivers/watchdog/as3722_wdt.c | 300 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/as3722.h    |   1 +
 4 files changed, 311 insertions(+)
 create mode 100644 drivers/watchdog/as3722_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 74f29a2..15a5c08 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -53,6 +53,15 @@ comment "Watchdog Device Drivers"
 
 # Architecture Independent
 
+config AS3722_WATCHDOG
+	tristate "AS3722 watchdog"
+	depends on MFD_AS3722
+	select WATCHDOG_CORE
+	help
+	  Support for the watchdog in the AMS AS3722 PMIC.  When
+	  the watchdog triggers the system will be reset/Off based on
+	  configuration.
+
 config SOFT_WATCHDOG
 	tristate "Software watchdog"
 	select WATCHDOG_CORE
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 91bd95a..dab02f8 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -169,6 +169,7 @@ obj-$(CONFIG_WATCHDOG_CP1XXX)		+= cpwd.o
 obj-$(CONFIG_XEN_WDT) += xen_wdt.o
 
 # Architecture Independent
+obj-$(CONFIG_AS3722_WATCHDOG) += as3722_wdt.o
 obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o
 obj-$(CONFIG_DA9055_WATCHDOG) += da9055_wdt.o
 obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
diff --git a/drivers/watchdog/as3722_wdt.c b/drivers/watchdog/as3722_wdt.c
new file mode 100644
index 0000000..0ce0866
--- /dev/null
+++ b/drivers/watchdog/as3722_wdt.c
@@ -0,0 +1,300 @@
+/*
+ * as3722_wdt.c -- AS3722 Watchdog Timer.
+ *
+ * Watchdog timer for AS3722 PMIC.
+ *
+ * Copyright (c) 2013, NVIDIA Corporation. All rights reserved.
+ *
+ * Author: Bibek Basu <bbasu@xxxxxxxxxx>
+ * based on Palmas_wdt driver (c) Laxman Dewangan , 2013
+ *
+ * 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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
+ * whether express or implied; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ */
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mfd/as3722.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/watchdog.h>
+#include <linux/of.h>
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+struct as3722_wdt {
+	struct watchdog_device wdt_dev;
+	struct device *dev;
+	struct as3722 *as3722;
+	int timeout;
+	int irq;
+	int timer_initial_period;
+	int timer_mode;
+};
+
+static irqreturn_t as3722_wdt_irq(int irq, void *data)
+{
+	struct as3722_wdt *wdt = data;
+	int ret;
+
+	ret = as3722_update_bits(wdt->as3722,
+			AS3722_WATCHDOG_SOFTWARE_SIGNAL_REG,
+			AS3722_WATCHDOG_SW_SIG, AS3722_WATCHDOG_SW_SIG);
+	if (ret < 0)
+		dev_err(wdt->dev, "WATCHDOG kick failed: %d\n", ret);
+	dev_info(wdt->dev, "WDT interrupt occur\n");
+	return IRQ_HANDLED;
+}
+
+static int as3722_wdt_start(struct watchdog_device *wdt_dev)
+{
+	struct as3722_wdt *wdt = watchdog_get_drvdata(wdt_dev);
+	int ret;
+
+	ret = as3722_update_bits(wdt->as3722, AS3722_WATCHDOG_CONTROL_REG,
+			AS3722_WATCHDOG_ON, AS3722_WATCHDOG_ON);
+	if (ret < 0) {
+		dev_err(wdt->dev, "WATCHDOG update failed: %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static int as3722_wdt_stop(struct watchdog_device *wdt_dev)
+{
+	struct as3722_wdt *wdt = watchdog_get_drvdata(wdt_dev);
+	int ret;
+
+	ret = as3722_update_bits(wdt->as3722, AS3722_WATCHDOG_CONTROL_REG,
+			AS3722_WATCHDOG_ON, 0);
+	if (ret < 0) {
+		dev_err(wdt->dev, "WATCHDOG update failed: %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static int as3722_wdt_set_timeout(struct watchdog_device *wdt_dev,
+		unsigned int timeout)
+{
+	struct as3722_wdt *wdt = watchdog_get_drvdata(wdt_dev);
+	int ret;
+	unsigned int val = timeout - 1;
+
+	ret = as3722_update_bits(wdt->as3722, AS3722_WATCHDOG_TIMER_REG,
+			AS3722_WATCHDOG_TIMER_MAX, val);
+	if (ret < 0) {
+		dev_err(wdt->dev, "WATCHDOG update failed: %d\n", ret);
+		return ret;
+	}
+	wdt->timeout = timeout;
+	return 0;
+}
+
+static const struct watchdog_info as3722_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
+	.identity = "AS3722 Watchdog",
+};
+
+static const struct watchdog_ops as3722_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = as3722_wdt_start,
+	.stop = as3722_wdt_stop,
+	.set_timeout = as3722_wdt_set_timeout,
+};
+
+#ifdef CONFIG_OF
+static int as3722_parse_dt_wdt_data(
+		struct platform_device *pdev,
+		struct as3722_wdt *wdt)
+{
+	struct device_node *np = pdev->dev.of_node;
+	const __be32 *prop;
+
+	prop = of_get_property(np, "ams,timer_initial_period", NULL);
+	if (prop)
+		wdt->timer_initial_period = be32_to_cpu(*prop);
+
+	prop = of_get_property(np, "ams,timer_mode", NULL);
+	if (prop)
+		wdt->timer_mode =  be32_to_cpu(*prop);
+	else
+		wdt->timer_mode = -1;
+	return 0;
+}
+#else
+static inline int as3722_parse_dt_wdt_data(
+		struct platform_device *pdev,
+		struct as3722_wdt *wdt)
+{
+	return 0;
+}
+#endif
+
+static int as3722_wdt_probe(struct platform_device *pdev)
+{
+	struct as3722 *as3722 = dev_get_drvdata(pdev->dev.parent);
+	struct as3722_wdt *wdt;
+	struct watchdog_device *wdt_dev;
+	int ret;
+
+	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	as3722_parse_dt_wdt_data(pdev, wdt);
+	wdt->dev = &pdev->dev;
+	wdt->as3722 = as3722;
+	wdt->irq = as3722_irq_get_virq(wdt->as3722, AS3722_IRQ_WATCHDOG);
+	wdt_dev = &wdt->wdt_dev;
+
+	wdt_dev->info = &as3722_wdt_info;
+	wdt_dev->ops = &as3722_wdt_ops;
+	wdt_dev->timeout = 128;
+	wdt_dev->min_timeout = 8;
+	wdt_dev->max_timeout = 128;
+	watchdog_set_nowayout(wdt_dev, nowayout);
+	watchdog_set_drvdata(wdt_dev, wdt);
+	platform_set_drvdata(pdev, wdt);
+
+	ret = request_threaded_irq(wdt->irq, NULL, as3722_wdt_irq,
+			IRQF_ONESHOT | IRQF_EARLY_RESUME,
+			dev_name(&pdev->dev), wdt);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "request IRQ:%d failed, err = %d\n",
+			 wdt->irq, ret);
+		return ret;
+	}
+
+	ret = watchdog_register_device(wdt_dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "watchdog registration failed: %d\n", ret);
+		return ret;
+	}
+
+	/* set mode */
+	if (wdt->timer_mode >= 0) {
+		ret = as3722_update_bits(wdt->as3722,
+			AS3722_WATCHDOG_CONTROL_REG,
+			AS3722_WATCHDOG_MODE_MASK, wdt->timer_mode);
+		if (ret < 0) {
+			dev_err(wdt->dev, "WATCHDOG update mode failed: %d\n",
+					ret);
+			goto scrub;
+		}
+	}
+
+	/* configure timer */
+	if (wdt->timer_initial_period > 0) {
+		ret = as3722_wdt_set_timeout(wdt_dev,
+				wdt->timer_initial_period);
+		if (ret < 0) {
+			dev_err(wdt->dev, "wdt set timeout failed: %d\n", ret);
+			goto scrub;
+		}
+		ret = as3722_wdt_start(wdt_dev);
+		if (ret < 0) {
+			dev_err(wdt->dev,
+					"wdt start failed: %d\n", ret);
+			goto scrub;
+		}
+	}
+
+	device_set_wakeup_capable(&pdev->dev, 1);
+	return 0;
+scrub:
+	free_irq(wdt->irq, wdt);
+	watchdog_unregister_device(&wdt->wdt_dev);
+	return ret;
+}
+
+static int as3722_wdt_remove(struct platform_device *pdev)
+{
+	struct as3722_wdt *wdt = platform_get_drvdata(pdev);
+
+	as3722_wdt_stop(&wdt->wdt_dev);
+	watchdog_unregister_device(&wdt->wdt_dev);
+	free_irq(wdt->irq, wdt);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int as3722_wdt_suspend(struct device *dev)
+{
+	struct as3722_wdt *wdt = dev_get_drvdata(dev);
+	int ret;
+
+	if (device_may_wakeup(dev)) {
+		enable_irq_wake(wdt->irq);
+	} else if (wdt->timeout > 0) {
+		ret = as3722_wdt_stop(&wdt->wdt_dev);
+		if (ret < 0)
+			dev_err(wdt->dev, "wdt stop failed: %d\n", ret);
+	}
+	return 0;
+}
+
+static int as3722_wdt_resume(struct device *dev)
+{
+	struct as3722_wdt *wdt = dev_get_drvdata(dev);
+	int ret;
+
+	if (device_may_wakeup(dev)) {
+		disable_irq_wake(wdt->irq);
+	} else if (wdt->timeout > 0) {
+		ret = as3722_wdt_start(&wdt->wdt_dev);
+		if (ret < 0)
+			dev_err(wdt->dev, "wdt start failed: %d\n", ret);
+	}
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops as3722_wdt_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(as3722_wdt_suspend, as3722_wdt_resume)
+};
+
+static const struct of_device_id as3722_wdt_of_match[] = {
+	{ .compatible = "ams,as3722-wdt", },
+	{ /* end */ }
+};
+
+static struct platform_driver as3722_wdt_driver = {
+	.driver	= {
+		.name	= "as3722-wdt",
+		.owner	= THIS_MODULE,
+		.pm = &as3722_wdt_pm_ops,
+		.of_match_table = as3722_wdt_of_match,
+	},
+	.probe	= as3722_wdt_probe,
+	.remove	= as3722_wdt_remove,
+};
+
+static int __init as3722_wdt_init(void)
+{
+	return platform_driver_register(&as3722_wdt_driver);
+}
+subsys_initcall(as3722_wdt_init);
+
+static void __exit as3722_wdt_exit(void)
+{
+	platform_driver_unregister(&as3722_wdt_driver);
+}
+module_exit(as3722_wdt_exit);
+
+MODULE_ALIAS("platform:as3722-wdt");
+MODULE_DESCRIPTION("AMS AS3722 watchdog timer driver");
+MODULE_AUTHOR("Bibek Basu <bbasu@xxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/as3722.h b/include/linux/mfd/as3722.h
index 16bf8a0..9290fd6 100644
--- a/include/linux/mfd/as3722.h
+++ b/include/linux/mfd/as3722.h
@@ -336,6 +336,7 @@
 #define AS3722_WATCHDOG_TIMER_MAX			0x7F
 #define AS3722_WATCHDOG_ON				BIT(0)
 #define AS3722_WATCHDOG_SW_SIG				BIT(0)
+#define AS3722_WATCHDOG_MODE_MASK                       0x06
 
 #define AS3722_EXT_CONTROL_ENABLE1			0x1
 #define AS3722_EXT_CONTROL_ENABLE2			0x2
-- 
1.8.1.5

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