1/*
  2 * Realtek RTD129x watchdog
  3 *
  4 * Copyright (c) 2017 Andreas Färber
  5 *
  6 * SPDX-License-Identifier: GPL-2.0+
  7 */
  8
  9#include <linux/bitops.h>
 10#include <linux/clk.h>
 11#include <linux/io.h>
 12#include <linux/module.h>
 13#include <linux/of.h>
 14#include <linux/of_address.h>
 15#include <linux/platform_device.h>
 16#include <linux/watchdog.h>
 17
 18#define RTD119X_TCWCR		0x0
 19#define RTD119X_TCWTR		0x4
 20#define RTD119X_TCWOV		0xc
 21
 22#define RTD119X_TCWCR_WDEN_DISABLED		0xa5
 23#define RTD119X_TCWCR_WDEN_ENABLED		0xff
 24#define RTD119X_TCWCR_WDEN_MASK			0xff
 25
 26#define RTD119X_TCWTR_WDCLR			BIT(0)
 27
 28struct rtd119x_watchdog_device {
 29	struct watchdog_device wdt_dev;
 30	void __iomem *base;
 31	struct clk *clk;
 32};
 33
 34static int rtd119x_wdt_start(struct watchdog_device *wdev)
 35{
 36	struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
 37	u32 val;
 38
 39	val = readl_relaxed(data->base + RTD119X_TCWCR);
 40	val &= ~RTD119X_TCWCR_WDEN_MASK;
 41	val |= RTD119X_TCWCR_WDEN_ENABLED;
 42	writel(val, data->base + RTD119X_TCWCR);
 43
 44	return 0;
 45}
 46
 47static int rtd119x_wdt_stop(struct watchdog_device *wdev)
 48{
 49	struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
 50	u32 val;
 51
 52	val = readl_relaxed(data->base + RTD119X_TCWCR);
 53	val &= ~RTD119X_TCWCR_WDEN_MASK;
 54	val |= RTD119X_TCWCR_WDEN_DISABLED;
 55	writel(val, data->base + RTD119X_TCWCR);
 56
 57	return 0;
 58}
 59
 60static int rtd119x_wdt_ping(struct watchdog_device *wdev)
 61{
 62	struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
 63
 64	writel_relaxed(RTD119X_TCWTR_WDCLR, data->base + RTD119X_TCWTR);
 65
 66	return rtd119x_wdt_start(wdev);
 67}
 68
 69static int rtd119x_wdt_set_timeout(struct watchdog_device *wdev, unsigned int val)
 70{
 71	struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
 72
 73	writel(val * clk_get_rate(data->clk), data->base + RTD119X_TCWOV);
 74
 75	data->wdt_dev.timeout = val;
 76
 77	return 0;
 78}
 79
 80static const struct watchdog_ops rtd119x_wdt_ops = {
 81	.owner = THIS_MODULE,
 82	.start		= rtd119x_wdt_start,
 83	.stop		= rtd119x_wdt_stop,
 84	.ping		= rtd119x_wdt_ping,
 85	.set_timeout	= rtd119x_wdt_set_timeout,
 86};
 87
 88static const struct watchdog_info rtd119x_wdt_info = {
 89	.identity = "rtd119x-wdt",
 90	.options = 0,
 91};
 92
 93static const struct of_device_id rtd119x_wdt_dt_ids[] = {
 94	 { .compatible = "realtek,rtd1295-watchdog" },
 95	 { }
 96};
 97
 98static int rtd119x_wdt_probe(struct platform_device *pdev)
 99{
100	struct rtd119x_watchdog_device *data;
101	struct resource *res;
102	int ret;
103
104	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
105	if (!data)
106		return -ENOMEM;
107
108	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
109	data->base = devm_ioremap_resource(&pdev->dev, res);
110	if (IS_ERR(data->base))
111		return PTR_ERR(data->base);
112
113	data->clk = of_clk_get(pdev->dev.of_node, 0);
114	if (IS_ERR(data->clk))
115		return PTR_ERR(data->clk);
116
117	ret = clk_prepare_enable(data->clk);
118	if (ret) {
119		clk_put(data->clk);
120		return ret;
121	}
122
123	data->wdt_dev.info = &rtd119x_wdt_info;
124	data->wdt_dev.ops = &rtd119x_wdt_ops;
125	data->wdt_dev.timeout = 120;
126	data->wdt_dev.max_timeout = 0xffffffff / clk_get_rate(data->clk);
127	data->wdt_dev.min_timeout = 1;
128	data->wdt_dev.parent = &pdev->dev;
129
130	watchdog_stop_on_reboot(&data->wdt_dev);
131	watchdog_set_drvdata(&data->wdt_dev, data);
132	platform_set_drvdata(pdev, data);
133
134	writel_relaxed(RTD119X_TCWTR_WDCLR, data->base + RTD119X_TCWTR);
135	rtd119x_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
136	rtd119x_wdt_stop(&data->wdt_dev);
137
138	ret = devm_watchdog_register_device(&pdev->dev, &data->wdt_dev);
139	if (ret) {
140		clk_disable_unprepare(data->clk);
141		clk_put(data->clk);
142		return ret;
143	}
144
145	return 0;
146}
147
148static int rtd119x_wdt_remove(struct platform_device *pdev)
149{
150	struct rtd119x_watchdog_device *data = platform_get_drvdata(pdev);
151
152	watchdog_unregister_device(&data->wdt_dev);
153
154	clk_disable_unprepare(data->clk);
155	clk_put(data->clk);
156
157	return 0;
158}
159
160static struct platform_driver rtd119x_wdt_driver = {
161	.probe = rtd119x_wdt_probe,
162	.remove = rtd119x_wdt_remove,
163	.driver = {
164		.name = "rtd1295-watchdog",
165		.of_match_table	= rtd119x_wdt_dt_ids,
166	},
167};
168builtin_platform_driver(rtd119x_wdt_driver);