1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Realtek RTD129x RTC
4 *
5 * Copyright (c) 2017 Andreas F��rber
6 */
7
8#include <linux/clk.h>
9#include <linux/io.h>
10#include <linux/module.h>
11#include <linux/of.h>
12#include <linux/of_address.h>
13#include <linux/platform_device.h>
14#include <linux/rtc.h>
15#include <linux/spinlock.h>
16
17#define RTD_RTCSEC		0x00
18#define RTD_RTCMIN		0x04
19#define RTD_RTCHR		0x08
20#define RTD_RTCDATE1		0x0c
21#define RTD_RTCDATE2		0x10
22#define RTD_RTCACR		0x28
23#define RTD_RTCEN		0x2c
24#define RTD_RTCCR		0x30
25
26#define RTD_RTCSEC_RTCSEC_MASK		0x7f
27
28#define RTD_RTCMIN_RTCMIN_MASK		0x3f
29
30#define RTD_RTCHR_RTCHR_MASK		0x1f
31
32#define RTD_RTCDATE1_RTCDATE1_MASK	0xff
33
34#define RTD_RTCDATE2_RTCDATE2_MASK	0x7f
35
36#define RTD_RTCACR_RTCPWR		BIT(7)
37
38#define RTD_RTCEN_RTCEN_MASK		0xff
39
40#define RTD_RTCCR_RTCRST		BIT(6)
41
42struct rtd119x_rtc {
43	void __iomem *base;
44	struct clk *clk;
45	struct rtc_device *rtcdev;
46	unsigned int base_year;
47};
48
49static inline int rtd119x_rtc_days_in_year(int year)
50{
51	return 365 + (is_leap_year(year) ? 1 : 0);
52}
53
54static void rtd119x_rtc_reset(struct device *dev)
55{
56	struct rtd119x_rtc *data = dev_get_drvdata(dev);
57	u32 val;
58
59	val = readl_relaxed(data->base + RTD_RTCCR);
60	val |= RTD_RTCCR_RTCRST;
61	writel_relaxed(val, data->base + RTD_RTCCR);
62
63	val &= ~RTD_RTCCR_RTCRST;
64	writel(val, data->base + RTD_RTCCR);
65}
66
67static void rtd119x_rtc_set_enabled(struct device *dev, bool enable)
68{
69	struct rtd119x_rtc *data = dev_get_drvdata(dev);
70	u32 val;
71
72	val = readl_relaxed(data->base + RTD_RTCEN);
73	if (enable) {
74		if ((val & RTD_RTCEN_RTCEN_MASK) == 0x5a)
75			return;
76		writel_relaxed(0x5a, data->base + RTD_RTCEN);
77	} else {
78		writel_relaxed(0, data->base + RTD_RTCEN);
79	}
80}
81
82static int rtd119x_rtc_read_time(struct device *dev, struct rtc_time *tm)
83{
84	struct rtd119x_rtc *data = dev_get_drvdata(dev);
85	s32 day;
86	u32 sec;
87	unsigned int year;
88	int tries = 0;
89
90	while (true) {
91		tm->tm_sec = (readl_relaxed(data->base + RTD_RTCSEC) & RTD_RTCSEC_RTCSEC_MASK) >> 1;
92		tm->tm_min  = readl_relaxed(data->base + RTD_RTCMIN) & RTD_RTCMIN_RTCMIN_MASK;
93		tm->tm_hour = readl_relaxed(data->base + RTD_RTCHR) & RTD_RTCHR_RTCHR_MASK;
94		day  =  readl_relaxed(data->base + RTD_RTCDATE1) & RTD_RTCDATE1_RTCDATE1_MASK;
95		day |= (readl_relaxed(data->base + RTD_RTCDATE2) & RTD_RTCDATE2_RTCDATE2_MASK) << 8;
96		sec  = (readl_relaxed(data->base + RTD_RTCSEC) & RTD_RTCSEC_RTCSEC_MASK) >> 1;
97		tries++;
98
99		if (sec == tm->tm_sec)
100			break;
101
102		if (tries >= 3)
103			return -EINVAL;
104	}
105	if (tries > 1)
106		dev_dbg(dev, "%s: needed %i tries\n", __func__, tries);
107
108	year = data->base_year;
109	while (day >= rtd119x_rtc_days_in_year(year)) {
110		day -= rtd119x_rtc_days_in_year(year);
111		year++;
112	}
113	tm->tm_year = year - 1900;
114	tm->tm_yday = day;
115
116	tm->tm_mon = 0;
117	while (day >= rtc_month_days(tm->tm_mon, year)) {
118		day -= rtc_month_days(tm->tm_mon, year);
119		tm->tm_mon++;
120	}
121	tm->tm_mday = day + 1;
122
123	return 0;
124}
125
126static int rtd119x_rtc_set_time(struct device *dev, struct rtc_time *tm)
127{
128	struct rtd119x_rtc *data = dev_get_drvdata(dev);
129	unsigned int day;
130	int i;
131
132	if (1900 + tm->tm_year < data->base_year)
133		return -EINVAL;
134
135	day = 0;
136	for (i = data->base_year; i < 1900 + tm->tm_year; i++)
137		day += rtd119x_rtc_days_in_year(i);
138
139	day += tm->tm_yday;
140	if (day > 0x7fff)
141		return -EINVAL;
142
143	rtd119x_rtc_set_enabled(dev, false);
144
145	writel_relaxed((tm->tm_sec << 1) & RTD_RTCSEC_RTCSEC_MASK, data->base + RTD_RTCSEC);
146	writel_relaxed(tm->tm_min & RTD_RTCMIN_RTCMIN_MASK, data->base + RTD_RTCMIN);
147	writel_relaxed(tm->tm_hour & RTD_RTCHR_RTCHR_MASK, data->base + RTD_RTCHR);
148	writel_relaxed(day & RTD_RTCDATE1_RTCDATE1_MASK, data->base + RTD_RTCDATE1);
149	writel_relaxed((day >> 8) & RTD_RTCDATE2_RTCDATE2_MASK, data->base + RTD_RTCDATE2);
150
151	rtd119x_rtc_set_enabled(dev, true);
152
153	return 0;
154}
155
156static const struct rtc_class_ops rtd119x_rtc_ops = {
157	.read_time	= rtd119x_rtc_read_time,
158	.set_time	= rtd119x_rtc_set_time,
159};
160
161static const struct of_device_id rtd119x_rtc_dt_ids[] = {
162	 { .compatible = "realtek,rtd1295-rtc" },
163	 { }
164};
165
166static int rtd119x_rtc_probe(struct platform_device *pdev)
167{
168	struct rtd119x_rtc *data;
169	u32 val;
170	int ret;
171
172	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
173	if (!data)
174		return -ENOMEM;
175
176	platform_set_drvdata(pdev, data);
177	data->base_year = 2014;
178
179	data->base = devm_platform_ioremap_resource(pdev, 0);
180	if (IS_ERR(data->base))
181		return PTR_ERR(data->base);
182
183	data->clk = of_clk_get(pdev->dev.of_node, 0);
184	if (IS_ERR(data->clk))
185		return PTR_ERR(data->clk);
186
187	ret = clk_prepare_enable(data->clk);
188	if (ret) {
189		clk_put(data->clk);
190		return ret;
191	}
192
193	val = readl_relaxed(data->base + RTD_RTCACR);
194	if (!(val & RTD_RTCACR_RTCPWR)) {
195		writel_relaxed(RTD_RTCACR_RTCPWR, data->base + RTD_RTCACR);
196
197		rtd119x_rtc_reset(&pdev->dev);
198
199		writel_relaxed(0, data->base + RTD_RTCMIN);
200		writel_relaxed(0, data->base + RTD_RTCHR);
201		writel_relaxed(0, data->base + RTD_RTCDATE1);
202		writel_relaxed(0, data->base + RTD_RTCDATE2);
203	}
204
205	rtd119x_rtc_set_enabled(&pdev->dev, true);
206
207	data->rtcdev = devm_rtc_device_register(&pdev->dev, "rtc",
208						&rtd119x_rtc_ops, THIS_MODULE);
209	if (IS_ERR(data->rtcdev)) {
210		dev_err(&pdev->dev, "failed to register rtc device");
211		clk_disable_unprepare(data->clk);
212		clk_put(data->clk);
213		return PTR_ERR(data->rtcdev);
214	}
215
216	return 0;
217}
218
219static void rtd119x_rtc_remove(struct platform_device *pdev)
220{
221	struct rtd119x_rtc *data = platform_get_drvdata(pdev);
222
223	rtd119x_rtc_set_enabled(&pdev->dev, false);
224
225	clk_disable_unprepare(data->clk);
226	clk_put(data->clk);
227}
228
229static struct platform_driver rtd119x_rtc_driver = {
230	.probe = rtd119x_rtc_probe,
231	.remove_new = rtd119x_rtc_remove,
232	.driver = {
233		.name = "rtd1295-rtc",
234		.of_match_table	= rtd119x_rtc_dt_ids,
235	},
236};
237builtin_platform_driver(rtd119x_rtc_driver);
238