--- /dev/null
+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ */
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#define WDT_RST 0x0
+#define WDT_EN 0x8
+#define WDT_BITE_TIME 0x24
+
+struct qcom_wdt {
+ struct watchdog_device wdd;
+ struct clk *clk;
+ unsigned long rate;
+ void __iomem *base;
+};
+
+static inline
+struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
+{
+ return container_of(wdd, struct qcom_wdt, wdd);
+}
+
+static int qcom_wdt_start(struct watchdog_device *wdd)
+{
+ struct qcom_wdt *wdt = to_qcom_wdt(wdd);
+
+ writel(0, wdt->base + WDT_EN);
+ writel(1, wdt->base + WDT_RST);
+ writel(wdd->timeout * wdt->rate, wdt->base + WDT_BITE_TIME);
+ writel(1, wdt->base + WDT_EN);
+ return 0;
+}
+
+static int qcom_wdt_stop(struct watchdog_device *wdd)
+{
+ struct qcom_wdt *wdt = to_qcom_wdt(wdd);
+
+ writel(0, wdt->base + WDT_EN);
+ return 0;
+}
+
+static int qcom_wdt_ping(struct watchdog_device *wdd)
+{
+ struct qcom_wdt *wdt = to_qcom_wdt(wdd);
+
+ writel(1, wdt->base + WDT_RST);
+ return 0;
+}
+
+static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ wdd->timeout = timeout;
+ return qcom_wdt_start(wdd);
+}
+
+static const struct watchdog_ops qcom_wdt_ops = {
+ .start = qcom_wdt_start,
+ .stop = qcom_wdt_stop,
+ .ping = qcom_wdt_ping,
+ .set_timeout = qcom_wdt_set_timeout,
+ .owner = THIS_MODULE,
+};
+
+static const struct watchdog_info qcom_wdt_info = {
+ .options = WDIOF_KEEPALIVEPING
+ | WDIOF_MAGICCLOSE
+ | WDIOF_SETTIMEOUT,
+ .identity = KBUILD_MODNAME,
+};
+
+static int qcom_wdt_probe(struct platform_device *pdev)
+{
+ struct qcom_wdt *wdt;
+ struct resource *res;
+ int ret;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ wdt->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(wdt->base))
+ return PTR_ERR(wdt->base);
+
+ wdt->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(wdt->clk)) {
+ dev_err(&pdev->dev, "failed to get input clock\n");
+ return PTR_ERR(wdt->clk);
+ }
+
+ ret = clk_prepare_enable(wdt->clk);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to setup clock\n");
+ return ret;
+ }
+
+ /*
+ * We use the clock rate to calculate the max timeout, so ensure it's
+ * not zero to avoid a divide-by-zero exception.
+ *
+ * WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
+ * that it would bite before a second elapses it's usefulness is
+ * limited. Bail if this is the case.
+ */
+ wdt->rate = clk_get_rate(wdt->clk);
+ if (wdt->rate == 0 ||
+ wdt->rate > 0x10000000U) {
+ dev_err(&pdev->dev, "invalid clock rate\n");
+ ret = -EINVAL;
+ goto err_clk_unprepare;
+ }
+
+ wdt->wdd.dev = &pdev->dev;
+ wdt->wdd.info = &qcom_wdt_info;
+ wdt->wdd.ops = &qcom_wdt_ops;
+ wdt->wdd.min_timeout = 1;
+ wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
+
+ /*
+ * If 'timeout-sec' unspecified in devicetree, assume a 30 second
+ * default, unless the max timeout is less than 30 seconds, then use
+ * the max instead.
+ */
+ wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
+ watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
+
+ ret = watchdog_register_device(&wdt->wdd);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register watchdog\n");
+ goto err_clk_unprepare;
+ }
+
+ platform_set_drvdata(pdev, wdt);
+ return 0;
+
+err_clk_unprepare:
+ clk_disable_unprepare(wdt->clk);
+ return ret;
+}
+
+static int qcom_wdt_remove(struct platform_device *pdev)
+{
+ struct qcom_wdt *wdt = platform_get_drvdata(pdev);
+
+ watchdog_unregister_device(&wdt->wdd);
+ clk_disable_unprepare(wdt->clk);
+ return 0;
+}
+
+static const struct of_device_id qcom_wdt_of_table[] = {
+ { .compatible = "qcom,kpss-wdt-msm8960", },
+ { .compatible = "qcom,kpss-wdt-apq8064", },
+ { .compatible = "qcom,kpss-wdt-ipq8064", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);
+
+static struct platform_driver qcom_watchdog_driver = {
+ .probe = qcom_wdt_probe,
+ .remove = qcom_wdt_remove,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = qcom_wdt_of_table,
+ },
+};
+module_platform_driver(qcom_watchdog_driver);
+
+MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
+MODULE_LICENSE("GPL v2");
projects / mirror_ubuntu-zesty-kernel.git / commitdiff