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 = 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