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