diff options
Diffstat (limited to 'drivers/watchdog/rtd119x_wdt.c')
| -rw-r--r-- | drivers/watchdog/rtd119x_wdt.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/drivers/watchdog/rtd119x_wdt.c b/drivers/watchdog/rtd119x_wdt.c new file mode 100644 index 000000000000..d001c17ddfde --- /dev/null +++ b/drivers/watchdog/rtd119x_wdt.c @@ -0,0 +1,168 @@ +/* + * 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/module.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 int rtd119x_wdt_probe(struct platform_device *pdev) +{ + struct rtd119x_watchdog_device *data; + struct resource *res; + int ret; + + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + data->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(data->base)) + return PTR_ERR(data->base); + + data->clk = of_clk_get(pdev->dev.of_node, 0); + if (IS_ERR(data->clk)) + return PTR_ERR(data->clk); + + ret = clk_prepare_enable(data->clk); + if (ret) { + clk_put(data->clk); + 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 = &pdev->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); + + ret = devm_watchdog_register_device(&pdev->dev, &data->wdt_dev); + if (ret) { + clk_disable_unprepare(data->clk); + clk_put(data->clk); + return ret; + } + + return 0; +} + +static int rtd119x_wdt_remove(struct platform_device *pdev) +{ + struct rtd119x_watchdog_device *data = platform_get_drvdata(pdev); + + watchdog_unregister_device(&data->wdt_dev); + + clk_disable_unprepare(data->clk); + clk_put(data->clk); + + return 0; +} + +static struct platform_driver rtd119x_wdt_driver = { + .probe = rtd119x_wdt_probe, + .remove = rtd119x_wdt_remove, + .driver = { + .name = "rtd1295-watchdog", + .of_match_table = rtd119x_wdt_dt_ids, + }, +}; +builtin_platform_driver(rtd119x_wdt_driver); |