[WATCHDOG] twl4030 watchdog driver

Implementation of twl4030 watchdog driver.

Signed-off-by: Timo Kokkonen <timo.t.kokkonen@nokia.com>
Signed-off-by: Atal Shargorodsky <ext-atal.shargorodsky@nokia.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 272 insertions, 0 deletions

diff --git a/drivers/watchdog/twl4030_wdt.c b/drivers/watchdog/twl4030_wdt.c
new file mode 100644
index 000000000000..cb46556f2973
--- /dev/null
+++ b/drivers/watchdog/twl4030_wdt.c
@@ -0,0 +1,272 @@
+/*
+ * Copyright (C) Nokia Corporation
+ *
+ * Written by Timo Kokkonen <timo.t.kokkonen at nokia.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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; 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/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/miscdevice.h>
+#include <linux/uaccess.h>
+#include <linux/i2c/twl4030.h>
+
+#define TWL4030_WATCHDOG_CFG_REG_OFFS   0x3
+
+#define TWL4030_WDT_STATE_OPEN          0x1
+#define TWL4030_WDT_STATE_ACTIVE        0x8
+
+static struct platform_device *twl4030_wdt_dev;
+
+struct twl4030_wdt {
+        struct miscdevice       miscdev;
+        int                     timer_margin;
+        unsigned long           state;
+};
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
+        "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static int twl4030_wdt_write(unsigned char val)
+{
+        return twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, val,
+                                        TWL4030_WATCHDOG_CFG_REG_OFFS);
+}
+
+static int twl4030_wdt_enable(struct twl4030_wdt *wdt)
+{
+        return twl4030_wdt_write(wdt->timer_margin + 1);
+}
+
+static int twl4030_wdt_disable(struct twl4030_wdt *wdt)
+{
+        return twl4030_wdt_write(0);
+}
+
+static int twl4030_wdt_set_timeout(struct twl4030_wdt *wdt, int timeout)
+{
+        if (timeout < 0 || timeout > 30) {
+                dev_warn(wdt->miscdev.parent,
+                        "Timeout can only be in the range [0-30] seconds");
+                return -EINVAL;
+        }
+        wdt->timer_margin = timeout;
+        return twl4030_wdt_enable(wdt);
+}
+
+static ssize_t twl4030_wdt_write_fop(struct file *file,
+                const char __user *data, size_t len, loff_t *ppos)
+{
+        struct twl4030_wdt *wdt = file->private_data;
+
+        if (len)
+                twl4030_wdt_enable(wdt);
+
+        return len;
+}
+
+static long twl4030_wdt_ioctl(struct file *file,
+                unsigned int cmd, unsigned long arg)
+{
+        void __user *argp = (void __user *)arg;
+        int __user *p = argp;
+        int new_margin;
+        struct twl4030_wdt *wdt = file->private_data;
+
+        static const struct watchdog_info twl4030_wd_ident = {
+                .identity = "TWL4030 Watchdog",
+                .options = WDIOF_SETTIMEOUT,
+                .firmware_version = 0,
+        };
+
+        switch (cmd) {
+        case WDIOC_GETSUPPORT:
+                return copy_to_user(argp, &twl4030_wd_ident,
+                                sizeof(twl4030_wd_ident)) ? -EFAULT : 0;
+
+        case WDIOC_GETSTATUS:
+        case WDIOC_GETBOOTSTATUS:
+                return put_user(0, p);
+
+        case WDIOC_KEEPALIVE:
+                twl4030_wdt_enable(wdt);
+                break;
+
+        case WDIOC_SETTIMEOUT:
+                if (get_user(new_margin, p))
+                        return -EFAULT;
+                if (twl4030_wdt_set_timeout(wdt, new_margin))
+                        return -EINVAL;
+                return put_user(wdt->timer_margin, p);
+
+        case WDIOC_GETTIMEOUT:
+                return put_user(wdt->timer_margin, p);
+
+        default:
+                return -ENOTTY;
+        }
+
+        return 0;
+}
+
+static int twl4030_wdt_open(struct inode *inode, struct file *file)
+{
+        struct twl4030_wdt *wdt = platform_get_drvdata(twl4030_wdt_dev);
+
+        /* /dev/watchdog can only be opened once */
+        if (test_and_set_bit(0, &wdt->state))
+                return -EBUSY;
+
+        wdt->state |= TWL4030_WDT_STATE_ACTIVE;
+        file->private_data = (void *) wdt;
+
+        twl4030_wdt_enable(wdt);
+        return nonseekable_open(inode, file);
+}
+
+static int twl4030_wdt_release(struct inode *inode, struct file *file)
+{
+        struct twl4030_wdt *wdt = file->private_data;
+        if (nowayout) {
+                dev_alert(wdt->miscdev.parent,
+                       "Unexpected close, watchdog still running!\n");
+                twl4030_wdt_enable(wdt);
+        } else {
+                if (twl4030_wdt_disable(wdt))
+                        return -EFAULT;
+                wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
+        }
+
+        clear_bit(0, &wdt->state);
+        return 0;
+}
+
+static const struct file_operations twl4030_wdt_fops = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .open           = twl4030_wdt_open,
+        .release        = twl4030_wdt_release,
+        .unlocked_ioctl = twl4030_wdt_ioctl,
+        .write          = twl4030_wdt_write_fop,
+};
+
+static int __devinit twl4030_wdt_probe(struct platform_device *pdev)
+{
+        int ret = 0;
+        struct twl4030_wdt *wdt;
+
+        wdt = kzalloc(sizeof(struct twl4030_wdt), GFP_KERNEL);
+        if (!wdt)
+                return -ENOMEM;
+
+        wdt->state              = 0;
+        wdt->timer_margin       = 30;
+        wdt->miscdev.parent     = &pdev->dev;
+        wdt->miscdev.fops       = &twl4030_wdt_fops;
+        wdt->miscdev.minor      = WATCHDOG_MINOR;
+        wdt->miscdev.name       = "watchdog";
+
+        platform_set_drvdata(pdev, wdt);
+
+        twl4030_wdt_dev = pdev;
+
+        ret = misc_register(&wdt->miscdev);
+        if (ret) {
+                dev_err(wdt->miscdev.parent,
+                        "Failed to register misc device\n");
+                platform_set_drvdata(pdev, NULL);
+                kfree(wdt);
+                twl4030_wdt_dev = NULL;
+                return ret;
+        }
+        return 0;
+}
+
+static int __devexit twl4030_wdt_remove(struct platform_device *pdev)
+{
+        struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
+
+        if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
+                if (twl4030_wdt_disable(wdt))
+                        return -EFAULT;
+
+        wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
+        misc_deregister(&wdt->miscdev);
+
+        platform_set_drvdata(pdev, NULL);
+        kfree(wdt);
+        twl4030_wdt_dev = NULL;
+
+        return 0;
+}
+
+#ifdef CONFIG_PM
+static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
+{
+        struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
+        if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
+                return twl4030_wdt_disable(wdt);
+
+        return 0;
+}
+
+static int twl4030_wdt_resume(struct platform_device *pdev)
+{
+        struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
+        if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
+                return twl4030_wdt_enable(wdt);
+
+        return 0;
+}
+#else
+#define twl4030_wdt_suspend        NULL
+#define twl4030_wdt_resume         NULL
+#endif
+
+static struct platform_driver twl4030_wdt_driver = {
+        .probe          = twl4030_wdt_probe,
+        .remove         = __devexit_p(twl4030_wdt_remove),
+        .suspend        = twl4030_wdt_suspend,
+        .resume         = twl4030_wdt_resume,
+        .driver         = {
+                .owner  = THIS_MODULE,
+                .name   = "twl4030_wdt",
+        },
+};
+
+static int __devinit twl4030_wdt_init(void)
+{
+        return platform_driver_register(&twl4030_wdt_driver);
+}
+module_init(twl4030_wdt_init);
+
+static void __devexit twl4030_wdt_exit(void)
+{
+        platform_driver_unregister(&twl4030_wdt_driver);
+}
+module_exit(twl4030_wdt_exit);
+
+MODULE_AUTHOR("Nokia Corporation");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform:twl4030_wdt");
+