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Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[mirror_ubuntu-focal-kernel.git] / drivers / rtc / rtc-goldfish.c
1 // SPDX-License-Identifier: GPL-2.0
2 /* drivers/rtc/rtc-goldfish.c
3 *
4 * Copyright (C) 2007 Google, Inc.
5 * Copyright (C) 2017 Imagination Technologies Ltd.
6 */
7
8 #include <linux/io.h>
9 #include <linux/module.h>
10 #include <linux/of.h>
11 #include <linux/platform_device.h>
12 #include <linux/rtc.h>
13
14 #define TIMER_TIME_LOW 0x00 /* get low bits of current time */
15 /* and update TIMER_TIME_HIGH */
16 #define TIMER_TIME_HIGH 0x04 /* get high bits of time at last */
17 /* TIMER_TIME_LOW read */
18 #define TIMER_ALARM_LOW 0x08 /* set low bits of alarm and */
19 /* activate it */
20 #define TIMER_ALARM_HIGH 0x0c /* set high bits of next alarm */
21 #define TIMER_IRQ_ENABLED 0x10
22 #define TIMER_CLEAR_ALARM 0x14
23 #define TIMER_ALARM_STATUS 0x18
24 #define TIMER_CLEAR_INTERRUPT 0x1c
25
26 struct goldfish_rtc {
27 void __iomem *base;
28 int irq;
29 struct rtc_device *rtc;
30 };
31
32 static int goldfish_rtc_read_alarm(struct device *dev,
33 struct rtc_wkalrm *alrm)
34 {
35 u64 rtc_alarm;
36 u64 rtc_alarm_low;
37 u64 rtc_alarm_high;
38 void __iomem *base;
39 struct goldfish_rtc *rtcdrv;
40
41 rtcdrv = dev_get_drvdata(dev);
42 base = rtcdrv->base;
43
44 rtc_alarm_low = readl(base + TIMER_ALARM_LOW);
45 rtc_alarm_high = readl(base + TIMER_ALARM_HIGH);
46 rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low;
47
48 do_div(rtc_alarm, NSEC_PER_SEC);
49 memset(alrm, 0, sizeof(struct rtc_wkalrm));
50
51 rtc_time64_to_tm(rtc_alarm, &alrm->time);
52
53 if (readl(base + TIMER_ALARM_STATUS))
54 alrm->enabled = 1;
55 else
56 alrm->enabled = 0;
57
58 return 0;
59 }
60
61 static int goldfish_rtc_set_alarm(struct device *dev,
62 struct rtc_wkalrm *alrm)
63 {
64 struct goldfish_rtc *rtcdrv;
65 u64 rtc_alarm64;
66 u64 rtc_status_reg;
67 void __iomem *base;
68
69 rtcdrv = dev_get_drvdata(dev);
70 base = rtcdrv->base;
71
72 if (alrm->enabled) {
73 rtc_alarm64 = rtc_tm_to_time64(&alrm->time) * NSEC_PER_SEC;
74 writel((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
75 writel(rtc_alarm64, base + TIMER_ALARM_LOW);
76 } else {
77 /*
78 * if this function was called with enabled=0
79 * then it could mean that the application is
80 * trying to cancel an ongoing alarm
81 */
82 rtc_status_reg = readl(base + TIMER_ALARM_STATUS);
83 if (rtc_status_reg)
84 writel(1, base + TIMER_CLEAR_ALARM);
85 }
86
87 return 0;
88 }
89
90 static int goldfish_rtc_alarm_irq_enable(struct device *dev,
91 unsigned int enabled)
92 {
93 void __iomem *base;
94 struct goldfish_rtc *rtcdrv;
95
96 rtcdrv = dev_get_drvdata(dev);
97 base = rtcdrv->base;
98
99 if (enabled)
100 writel(1, base + TIMER_IRQ_ENABLED);
101 else
102 writel(0, base + TIMER_IRQ_ENABLED);
103
104 return 0;
105 }
106
107 static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
108 {
109 struct goldfish_rtc *rtcdrv = dev_id;
110 void __iomem *base = rtcdrv->base;
111
112 writel(1, base + TIMER_CLEAR_INTERRUPT);
113
114 rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
115
116 return IRQ_HANDLED;
117 }
118
119 static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
120 {
121 struct goldfish_rtc *rtcdrv;
122 void __iomem *base;
123 u64 time_high;
124 u64 time_low;
125 u64 time;
126
127 rtcdrv = dev_get_drvdata(dev);
128 base = rtcdrv->base;
129
130 time_low = readl(base + TIMER_TIME_LOW);
131 time_high = readl(base + TIMER_TIME_HIGH);
132 time = (time_high << 32) | time_low;
133
134 do_div(time, NSEC_PER_SEC);
135
136 rtc_time64_to_tm(time, tm);
137
138 return 0;
139 }
140
141 static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
142 {
143 struct goldfish_rtc *rtcdrv;
144 void __iomem *base;
145 u64 now64;
146
147 rtcdrv = dev_get_drvdata(dev);
148 base = rtcdrv->base;
149
150 now64 = rtc_tm_to_time64(tm) * NSEC_PER_SEC;
151 writel((now64 >> 32), base + TIMER_TIME_HIGH);
152 writel(now64, base + TIMER_TIME_LOW);
153
154 return 0;
155 }
156
157 static const struct rtc_class_ops goldfish_rtc_ops = {
158 .read_time = goldfish_rtc_read_time,
159 .set_time = goldfish_rtc_set_time,
160 .read_alarm = goldfish_rtc_read_alarm,
161 .set_alarm = goldfish_rtc_set_alarm,
162 .alarm_irq_enable = goldfish_rtc_alarm_irq_enable
163 };
164
165 static int goldfish_rtc_probe(struct platform_device *pdev)
166 {
167 struct goldfish_rtc *rtcdrv;
168 struct resource *r;
169 int err;
170
171 rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL);
172 if (!rtcdrv)
173 return -ENOMEM;
174
175 platform_set_drvdata(pdev, rtcdrv);
176
177 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
178 if (!r)
179 return -ENODEV;
180
181 rtcdrv->base = devm_ioremap_resource(&pdev->dev, r);
182 if (IS_ERR(rtcdrv->base))
183 return -ENODEV;
184
185 rtcdrv->irq = platform_get_irq(pdev, 0);
186 if (rtcdrv->irq < 0)
187 return -ENODEV;
188
189 rtcdrv->rtc = devm_rtc_allocate_device(&pdev->dev);
190 if (IS_ERR(rtcdrv->rtc))
191 return PTR_ERR(rtcdrv->rtc);
192
193 rtcdrv->rtc->ops = &goldfish_rtc_ops;
194 rtcdrv->rtc->range_max = U64_MAX / NSEC_PER_SEC;
195
196 err = devm_request_irq(&pdev->dev, rtcdrv->irq,
197 goldfish_rtc_interrupt,
198 0, pdev->name, rtcdrv);
199 if (err)
200 return err;
201
202 return rtc_register_device(rtcdrv->rtc);
203 }
204
205 static const struct of_device_id goldfish_rtc_of_match[] = {
206 { .compatible = "google,goldfish-rtc", },
207 {},
208 };
209 MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match);
210
211 static struct platform_driver goldfish_rtc = {
212 .probe = goldfish_rtc_probe,
213 .driver = {
214 .name = "goldfish_rtc",
215 .of_match_table = goldfish_rtc_of_match,
216 }
217 };
218
219 module_platform_driver(goldfish_rtc);
220
221 MODULE_LICENSE("GPL v2");