xref: /openbmc/linux/drivers/rtc/rtc-rtd119x.c (revision 0824a15b)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Realtek RTD129x RTC
4  *
5  * Copyright (c) 2017 Andreas Färber
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 
42 struct rtd119x_rtc {
43 	void __iomem *base;
44 	struct clk *clk;
45 	struct rtc_device *rtcdev;
46 	unsigned int base_year;
47 };
48 
rtd119x_rtc_days_in_year(int year)49 static inline int rtd119x_rtc_days_in_year(int year)
50 {
51 	return 365 + (is_leap_year(year) ? 1 : 0);
52 }
53 
rtd119x_rtc_reset(struct device * dev)54 static 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 
rtd119x_rtc_set_enabled(struct device * dev,bool enable)67 static 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 
rtd119x_rtc_read_time(struct device * dev,struct rtc_time * tm)82 static 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 
rtd119x_rtc_set_time(struct device * dev,struct rtc_time * tm)126 static 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 
156 static const struct rtc_class_ops rtd119x_rtc_ops = {
157 	.read_time	= rtd119x_rtc_read_time,
158 	.set_time	= rtd119x_rtc_set_time,
159 };
160 
161 static const struct of_device_id rtd119x_rtc_dt_ids[] = {
162 	 { .compatible = "realtek,rtd1295-rtc" },
163 	 { }
164 };
165 
rtd119x_rtc_probe(struct platform_device * pdev)166 static 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 
rtd119x_rtc_remove(struct platform_device * pdev)219 static 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 
229 static 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 };
237 builtin_platform_driver(rtd119x_rtc_driver);
238