--- /dev/null
+/*
+ * Moschip MCS814x Watchdog driver
+ *
+ * Copyright (C) 2012, Florian Fainelli <florian@openwrt.org>
+ *
+ * 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/slab.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+
+#define WDT_COUNT 0x00
+#define WDT_CTRL 0x04
+#define WDT_CTRL_EN 0x1
+
+/* watchdog frequency */
+#define WDT_MAX_VALUE (0xffffffff)
+
+struct mcs814x_wdt {
+ void __iomem *regs;
+ spinlock_t lock;
+ struct watchdog_device wdt_dev;
+ struct clk *clk;
+};
+
+static int mcs814x_wdt_start(struct watchdog_device *dev)
+{
+ struct mcs814x_wdt *wdt = watchdog_get_drvdata(dev);
+ u32 reg;
+
+ spin_lock(&wdt->lock);
+ reg = readl_relaxed(wdt->regs + WDT_CTRL);
+ reg |= WDT_CTRL_EN;
+ writel_relaxed(reg, wdt->regs + WDT_CTRL);
+ spin_unlock(&wdt->lock);
+
+ return 0;
+}
+
+static int mcs814x_wdt_stop(struct watchdog_device *dev)
+{
+ struct mcs814x_wdt *wdt = watchdog_get_drvdata(dev);
+ u32 reg;
+
+ spin_lock(&wdt->lock);
+ reg = readl_relaxed(wdt->regs + WDT_CTRL);
+ reg &= ~WDT_CTRL_EN;
+ writel_relaxed(reg, wdt->regs + WDT_CTRL);
+ spin_unlock(&wdt->lock);
+
+ return 0;
+}
+
+static int mcs814x_wdt_set_timeout(struct watchdog_device *dev,
+ unsigned int new_timeout)
+{
+ struct mcs814x_wdt *wdt = watchdog_get_drvdata(dev);
+
+ spin_lock(&wdt->lock);
+ /* watchdog counts upward and rollover (0xfffffff -> 0)
+ * triggers the reboot
+ */
+ writel_relaxed(WDT_MAX_VALUE - (new_timeout * clk_get_rate(wdt->clk)),
+ wdt->regs + WDT_COUNT);
+ spin_unlock(&wdt->lock);
+
+ return 0;
+}
+
+static int mcs814x_wdt_ping(struct watchdog_device *dev)
+{
+ /* restart the watchdog */
+ mcs814x_wdt_stop(dev);
+ mcs814x_wdt_set_timeout(dev, dev->timeout);
+ mcs814x_wdt_start(dev);
+
+ return 0;
+}
+
+static const struct watchdog_info mcs814x_wdt_ident = {
+ .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT |
+ WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+ .identity = "MCS814x Watchdog",
+};
+
+static struct watchdog_ops mcs814x_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = mcs814x_wdt_start,
+ .stop = mcs814x_wdt_stop,
+ .set_timeout = mcs814x_wdt_set_timeout,
+ .ping = mcs814x_wdt_ping,
+};
+
+static int mcs814x_wdt_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct mcs814x_wdt *wdt;
+ int ret;
+ struct clk *clk;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ clk = clk_get(NULL, "wdt");
+ if (IS_ERR_OR_NULL(clk)) {
+ dev_err(&pdev->dev, "failed to get watchdog clock\n");
+ return PTR_ERR(clk);
+ }
+
+ wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
+ if (!wdt) {
+ ret = -ENOMEM;
+ goto out_clk;
+ }
+
+ spin_lock_init(&wdt->lock);
+ wdt->clk = clk;
+ wdt->wdt_dev.info = &mcs814x_wdt_ident;
+ wdt->wdt_dev.ops = &mcs814x_wdt_ops;
+ wdt->wdt_dev.min_timeout = 1;
+ /* approximately 10995 secs */
+ wdt->wdt_dev.max_timeout = (WDT_MAX_VALUE / clk_get_rate(clk));
+
+ platform_set_drvdata(pdev, wdt);
+
+ /* only ioremap registers, because the register is shared */
+ wdt->regs = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+ if (!wdt->regs) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ watchdog_set_drvdata(&wdt->wdt_dev, wdt);
+
+ ret = watchdog_register_device(&wdt->wdt_dev);
+ if (ret) {
+ dev_err(&pdev->dev, "cannot register watchdog: %d\n", ret);
+ goto out;
+ }
+
+ dev_info(&pdev->dev, "registered\n");
+ return 0;
+
+out:
+ platform_set_drvdata(pdev, NULL);
+ kfree(wdt);
+out_clk:
+ clk_put(clk);
+ return ret;
+}
+
+static int mcs814x_wdt_remove(struct platform_device *pdev)
+{
+ struct mcs814x_wdt *wdt = platform_get_drvdata(pdev);
+
+ clk_put(wdt->clk);
+ watchdog_unregister_device(&wdt->wdt_dev);
+ watchdog_set_drvdata(&wdt->wdt_dev, NULL);
+ kfree(wdt);
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+static const struct of_device_id mcs814x_wdt_ids[] = {
+ { .compatible = "moschip,mcs814x-wdt", },
+ { /* sentinel */ },
+};
+
+static struct platform_driver mcs814x_wdt_driver = {
+ .driver = {
+ .name = "mcs814x-wdt",
+ .owner = THIS_MODULE,
+ .of_match_table = mcs814x_wdt_ids,
+ },
+ .probe = mcs814x_wdt_probe,
+ .remove = mcs814x_wdt_remove,
+};
+
+module_platform_driver(mcs814x_wdt_driver);
+
+MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
+MODULE_DESCRIPTION("Moschip MCS814x Watchdog driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform:mcs814x-wdt");
projects / 15.05 / openwrt.git / blobdiff