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path: root/drivers/watchdog/rtd119x_wdt.c
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Diffstat (limited to 'drivers/watchdog/rtd119x_wdt.c')
-rw-r--r--drivers/watchdog/rtd119x_wdt.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/drivers/watchdog/rtd119x_wdt.c b/drivers/watchdog/rtd119x_wdt.c
new file mode 100644
index 000000000..834b94ff3
--- /dev/null
+++ b/drivers/watchdog/rtd119x_wdt.c
@@ -0,0 +1,153 @@
+/*
+ * Realtek RTD129x watchdog
+ *
+ * Copyright (c) 2017 Andreas Färber
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#define RTD119X_TCWCR 0x0
+#define RTD119X_TCWTR 0x4
+#define RTD119X_TCWOV 0xc
+
+#define RTD119X_TCWCR_WDEN_DISABLED 0xa5
+#define RTD119X_TCWCR_WDEN_ENABLED 0xff
+#define RTD119X_TCWCR_WDEN_MASK 0xff
+
+#define RTD119X_TCWTR_WDCLR BIT(0)
+
+struct rtd119x_watchdog_device {
+ struct watchdog_device wdt_dev;
+ void __iomem *base;
+ struct clk *clk;
+};
+
+static int rtd119x_wdt_start(struct watchdog_device *wdev)
+{
+ struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
+ u32 val;
+
+ val = readl_relaxed(data->base + RTD119X_TCWCR);
+ val &= ~RTD119X_TCWCR_WDEN_MASK;
+ val |= RTD119X_TCWCR_WDEN_ENABLED;
+ writel(val, data->base + RTD119X_TCWCR);
+
+ return 0;
+}
+
+static int rtd119x_wdt_stop(struct watchdog_device *wdev)
+{
+ struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
+ u32 val;
+
+ val = readl_relaxed(data->base + RTD119X_TCWCR);
+ val &= ~RTD119X_TCWCR_WDEN_MASK;
+ val |= RTD119X_TCWCR_WDEN_DISABLED;
+ writel(val, data->base + RTD119X_TCWCR);
+
+ return 0;
+}
+
+static int rtd119x_wdt_ping(struct watchdog_device *wdev)
+{
+ struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
+
+ writel_relaxed(RTD119X_TCWTR_WDCLR, data->base + RTD119X_TCWTR);
+
+ return rtd119x_wdt_start(wdev);
+}
+
+static int rtd119x_wdt_set_timeout(struct watchdog_device *wdev, unsigned int val)
+{
+ struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
+
+ writel(val * clk_get_rate(data->clk), data->base + RTD119X_TCWOV);
+
+ data->wdt_dev.timeout = val;
+
+ return 0;
+}
+
+static const struct watchdog_ops rtd119x_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = rtd119x_wdt_start,
+ .stop = rtd119x_wdt_stop,
+ .ping = rtd119x_wdt_ping,
+ .set_timeout = rtd119x_wdt_set_timeout,
+};
+
+static const struct watchdog_info rtd119x_wdt_info = {
+ .identity = "rtd119x-wdt",
+ .options = 0,
+};
+
+static const struct of_device_id rtd119x_wdt_dt_ids[] = {
+ { .compatible = "realtek,rtd1295-watchdog" },
+ { }
+};
+
+static void rtd119x_clk_disable_unprepare(void *data)
+{
+ clk_disable_unprepare(data);
+}
+
+static int rtd119x_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct rtd119x_watchdog_device *data;
+ int ret;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(data->base))
+ return PTR_ERR(data->base);
+
+ data->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(data->clk))
+ return PTR_ERR(data->clk);
+
+ ret = clk_prepare_enable(data->clk);
+ if (ret)
+ return ret;
+ ret = devm_add_action_or_reset(dev, rtd119x_clk_disable_unprepare,
+ data->clk);
+ if (ret)
+ return ret;
+
+ data->wdt_dev.info = &rtd119x_wdt_info;
+ data->wdt_dev.ops = &rtd119x_wdt_ops;
+ data->wdt_dev.timeout = 120;
+ data->wdt_dev.max_timeout = 0xffffffff / clk_get_rate(data->clk);
+ data->wdt_dev.min_timeout = 1;
+ data->wdt_dev.parent = dev;
+
+ watchdog_stop_on_reboot(&data->wdt_dev);
+ watchdog_set_drvdata(&data->wdt_dev, data);
+ platform_set_drvdata(pdev, data);
+
+ writel_relaxed(RTD119X_TCWTR_WDCLR, data->base + RTD119X_TCWTR);
+ rtd119x_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
+ rtd119x_wdt_stop(&data->wdt_dev);
+
+ return devm_watchdog_register_device(dev, &data->wdt_dev);
+}
+
+static struct platform_driver rtd119x_wdt_driver = {
+ .probe = rtd119x_wdt_probe,
+ .driver = {
+ .name = "rtd1295-watchdog",
+ .of_match_table = rtd119x_wdt_dt_ids,
+ },
+};
+builtin_platform_driver(rtd119x_wdt_driver);