watchdog: palmas: add palams wathdog timer

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

The driver also support wakeup capability and wakeup can be enable/disable
through user level power wakeup sysfs interface.

Change-Id: Icda02290f22ccdc45f2cfa675b8a7dae73f4d313
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-on: http://git-master/r/203663

3 files changed, 314 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index f6337394b2cc..63162a7552b8 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -53,6 +53,15 @@ comment "Watchdog Device Drivers"
 
 # Architecture Independent
 
+config PALMAS_WATCHDOG
+	tristate "PALMAS watchdog"
+	depends on MFD_PALMAS
+	select WATCHDOG_CORE
+	help
+	  Support for the watchdog in the TI Palmas PMIC PMICs.  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 a8030d225db9..eb8383a14c82 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -166,6 +166,7 @@ obj-$(CONFIG_WATCHDOG_CP1XXX)		+= cpwd.o
 obj-$(CONFIG_XEN_WDT) += xen_wdt.o
 
 # Architecture Independent
+obj-$(CONFIG_PALMAS_WATCHDOG) += palmas_wdt.o
 obj-$(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/palmas_wdt.c b/drivers/watchdog/palmas_wdt.c
new file mode 100644
index 000000000000..d85dfee5d09d
--- /dev/null
+++ b/drivers/watchdog/palmas_wdt.c
@@ -0,0 +1,304 @@
+/*
+ * palmas_wdt.c -- Palmas Watchdog Timer.
+ *
+ * Watchdog timer for Palmas PMIC.
+ *
+ * Copyright (c) 2013, NVIDIA Corporation.
+ *
+ * Author: Laxman Dewangan <ldewangan@nvidia.com>
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307, USA
+ */
+
+#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/palmas.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/watchdog.h>
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+struct palmas_wdt {
+	struct watchdog_device wdt_dev;
+	struct device *dev;
+	struct palmas *palmas;
+	int timeout;
+	int irq;
+	int locked;
+};
+
+static irqreturn_t palmas_wdt_irq(int irq, void *data)
+{
+	struct palmas_wdt *wdt = data;
+
+	dev_info(wdt->dev, "WDT interrupt occur\n");
+	return IRQ_HANDLED;
+}
+
+static int palmas_wdt_start(struct watchdog_device *wdt_dev)
+{
+	struct palmas_wdt *wdt = watchdog_get_drvdata(wdt_dev);
+	int ret;
+
+	if (wdt->locked) {
+		dev_err(wdt->dev,
+			"Watchdog timer is locked, can not control\n");
+		return -EBUSY;
+	}
+
+	ret = palmas_update_bits(wdt->palmas, PALMAS_PMU_CONTROL_BASE,
+			PALMAS_WATCHDOG, PALMAS_WATCHDOG_ENABLE,
+			PALMAS_WATCHDOG_ENABLE);
+	if (ret < 0) {
+		dev_err(wdt->dev, "WATCHDOG update failed: %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static int palmas_wdt_stop(struct watchdog_device *wdt_dev)
+{
+	struct palmas_wdt *wdt = watchdog_get_drvdata(wdt_dev);
+	int ret;
+
+	if (wdt->locked) {
+		dev_err(wdt->dev,
+			"Watchdog timer is locked, can not control\n");
+		return -EBUSY;
+	}
+
+	ret = palmas_update_bits(wdt->palmas, PALMAS_PMU_CONTROL_BASE,
+			PALMAS_WATCHDOG, PALMAS_WATCHDOG_ENABLE, 0);
+	if (ret < 0) {
+		dev_err(wdt->dev, "WATCHDOG update failed: %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static int palmas_wdt_set_timeout(struct watchdog_device *wdt_dev,
+		unsigned int timeout)
+{
+	struct palmas_wdt *wdt = watchdog_get_drvdata(wdt_dev);
+	int i;
+	int ret;
+	unsigned int bit = 1;
+
+	for (i = 0; i < 7; ++i) {
+		if (timeout <= bit)
+			break;
+
+		bit <<= 1;
+	}
+
+	ret = palmas_update_bits(wdt->palmas, PALMAS_PMU_CONTROL_BASE,
+			PALMAS_WATCHDOG, PALMAS_WATCHDOG_TIMER_MASK, i);
+	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 palmas_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
+	.identity = "Palmas Watchdog",
+};
+
+static const struct watchdog_ops palmas_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = palmas_wdt_start,
+	.stop = palmas_wdt_stop,
+	.set_timeout = palmas_wdt_set_timeout,
+};
+
+static int __devinit palmas_wdt_probe(struct platform_device *pdev)
+{
+	struct palmas_platform_data *pdata;
+	struct palmas_wdt *wdt;
+	struct watchdog_device *wdt_dev;
+	unsigned int regval;
+	int ret;
+
+	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	pdata = dev_get_platdata(pdev->dev.parent);
+
+	wdt->dev = &pdev->dev;
+	wdt->irq = platform_get_irq(pdev, 0);
+	wdt->palmas = dev_get_drvdata(pdev->dev.parent);
+	wdt_dev = &wdt->wdt_dev;
+
+	wdt_dev->info = &palmas_wdt_info;
+	wdt_dev->ops = &palmas_wdt_ops;
+	wdt_dev->timeout = 128;
+	wdt_dev->min_timeout = 1;
+	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, palmas_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;
+	}
+
+	ret = palmas_read(wdt->palmas, PALMAS_PMU_CONTROL_BASE,
+			PALMAS_WATCHDOG, &regval);
+	if (ret < 0) {
+		dev_err(wdt->dev, "WATCHDOG read failed: %d\n", ret);
+		goto scrub;
+	}
+
+	if (regval & PALMAS_WATCHDOG_LOCK) {
+		dev_info(wdt->dev, "watchdog timer Locked\n");
+		wdt->locked = true;
+	} else {
+		dev_info(wdt->dev, "watchdog timer unlocked\n");
+		wdt->locked = false;
+	}
+
+	if (!wdt->locked) {
+		ret = palmas_wdt_stop(wdt_dev);
+		if (ret < 0) {
+			dev_err(wdt->dev, "wdt stop failed: %d\n", ret);
+			goto scrub;
+		}
+	}
+
+	ret = palmas_update_bits(wdt->palmas, PALMAS_PMU_CONTROL_BASE,
+			PALMAS_WATCHDOG, PALMAS_WATCHDOG_MODE, 0);
+	if (ret < 0) {
+		dev_err(wdt->dev, "WATCHDOG update failed: %d\n", ret);
+		goto scrub;
+	}
+
+	if (pdata && (pdata->watchdog_timer_initial_period > 0)) {
+		ret = palmas_wdt_set_timeout(wdt_dev,
+					pdata->watchdog_timer_initial_period);
+		if (ret < 0) {
+			dev_err(wdt->dev, "wdt set timeout failed: %d\n", ret);
+			goto scrub;
+		}
+		if (!wdt->locked) {
+			ret = palmas_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 __devexit palmas_wdt_remove(struct platform_device *pdev)
+{
+	struct palmas_wdt *wdt = platform_get_drvdata(pdev);
+
+	palmas_wdt_stop(&wdt->wdt_dev);
+	watchdog_unregister_device(&wdt->wdt_dev);
+	free_irq(wdt->irq, wdt);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int palmas_wdt_suspend(struct device *dev)
+{
+	struct palmas_wdt *wdt = dev_get_drvdata(dev);
+	int ret;
+
+	if (device_may_wakeup(dev)) {
+		enable_irq_wake(wdt->irq);
+	} else if (wdt->timeout > 0) {
+		ret = palmas_wdt_stop(&wdt->wdt_dev);
+		if (ret < 0)
+			dev_err(wdt->dev, "wdt stop failed: %d\n", ret);
+	}
+	return 0;
+}
+
+static int palmas_wdt_resume(struct device *dev)
+{
+	struct palmas_wdt *wdt = dev_get_drvdata(dev);
+	int ret;
+
+	if (device_may_wakeup(dev)) {
+		disable_irq_wake(wdt->irq);
+	} else if (wdt->timeout > 0) {
+		ret = palmas_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 palmas_wdt_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(palmas_wdt_suspend, palmas_wdt_resume)
+};
+
+static struct platform_driver palmas_wdt_driver = {
+	.driver	= {
+		.name	= "palmas-wdt",
+		.owner	= THIS_MODULE,
+		.pm = &palmas_wdt_pm_ops,
+	},
+	.probe	= palmas_wdt_probe,
+	.remove	= __devexit_p(palmas_wdt_remove),
+};
+
+static int __init palmas_wdt_init(void)
+{
+	return platform_driver_register(&palmas_wdt_driver);
+}
+subsys_initcall(palmas_wdt_init);
+
+static void __exit palmas_wdt_exit(void)
+{
+	platform_driver_unregister(&palmas_wdt_driver);
+}
+module_exit(palmas_wdt_exit);
+
+MODULE_ALIAS("platform:palmas-wdt");
+MODULE_DESCRIPTION("TI Palmas watchdog timer driver");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_LICENSE("GPL v2");