1 /* drivers/rtc/rtc-goldfish.c
2 *
3 * Copyright (C) 2007 Google, Inc.
4 * Copyright (C) 2017 Imagination Technologies Ltd.
5 *
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 */
16
17 #include <linux/module.h>
18 #include <linux/platform_device.h>
19 #include <linux/rtc.h>
20 #include <linux/io.h>
21
22 #define TIMER_TIME_LOW 0x00 /* get low bits of current time */
23 /* and update TIMER_TIME_HIGH */
24 #define TIMER_TIME_HIGH 0x04 /* get high bits of time at last */
25 /* TIMER_TIME_LOW read */
26 #define TIMER_ALARM_LOW 0x08 /* set low bits of alarm and */
27 /* activate it */
28 #define TIMER_ALARM_HIGH 0x0c /* set high bits of next alarm */
29 #define TIMER_IRQ_ENABLED 0x10
30 #define TIMER_CLEAR_ALARM 0x14
31 #define TIMER_ALARM_STATUS 0x18
32 #define TIMER_CLEAR_INTERRUPT 0x1c
33
34 struct goldfish_rtc {
35 void __iomem *base;
36 int irq;
37 struct rtc_device *rtc;
38 };
39
goldfish_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)40 static int goldfish_rtc_read_alarm(struct device *dev,
41 struct rtc_wkalrm *alrm)
42 {
43 u64 rtc_alarm;
44 u64 rtc_alarm_low;
45 u64 rtc_alarm_high;
46 void __iomem *base;
47 struct goldfish_rtc *rtcdrv;
48
49 rtcdrv = dev_get_drvdata(dev);
50 base = rtcdrv->base;
51
52 rtc_alarm_low = readl(base + TIMER_ALARM_LOW);
53 rtc_alarm_high = readl(base + TIMER_ALARM_HIGH);
54 rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low;
55
56 do_div(rtc_alarm, NSEC_PER_SEC);
57 memset(alrm, 0, sizeof(struct rtc_wkalrm));
58
59 rtc_time_to_tm(rtc_alarm, &alrm->time);
60
61 if (readl(base + TIMER_ALARM_STATUS))
62 alrm->enabled = 1;
63 else
64 alrm->enabled = 0;
65
66 return 0;
67 }
68
goldfish_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)69 static int goldfish_rtc_set_alarm(struct device *dev,
70 struct rtc_wkalrm *alrm)
71 {
72 struct goldfish_rtc *rtcdrv;
73 unsigned long rtc_alarm;
74 u64 rtc_alarm64;
75 u64 rtc_status_reg;
76 void __iomem *base;
77 int ret = 0;
78
79 rtcdrv = dev_get_drvdata(dev);
80 base = rtcdrv->base;
81
82 if (alrm->enabled) {
83 ret = rtc_tm_to_time(&alrm->time, &rtc_alarm);
84 if (ret != 0)
85 return ret;
86
87 rtc_alarm64 = rtc_alarm * NSEC_PER_SEC;
88 writel((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
89 writel(rtc_alarm64, base + TIMER_ALARM_LOW);
90 } else {
91 /*
92 * if this function was called with enabled=0
93 * then it could mean that the application is
94 * trying to cancel an ongoing alarm
95 */
96 rtc_status_reg = readl(base + TIMER_ALARM_STATUS);
97 if (rtc_status_reg)
98 writel(1, base + TIMER_CLEAR_ALARM);
99 }
100
101 return ret;
102 }
103
goldfish_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)104 static int goldfish_rtc_alarm_irq_enable(struct device *dev,
105 unsigned int enabled)
106 {
107 void __iomem *base;
108 struct goldfish_rtc *rtcdrv;
109
110 rtcdrv = dev_get_drvdata(dev);
111 base = rtcdrv->base;
112
113 if (enabled)
114 writel(1, base + TIMER_IRQ_ENABLED);
115 else
116 writel(0, base + TIMER_IRQ_ENABLED);
117
118 return 0;
119 }
120
goldfish_rtc_interrupt(int irq,void * dev_id)121 static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
122 {
123 struct goldfish_rtc *rtcdrv = dev_id;
124 void __iomem *base = rtcdrv->base;
125
126 writel(1, base + TIMER_CLEAR_INTERRUPT);
127
128 rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
129
130 return IRQ_HANDLED;
131 }
132
goldfish_rtc_read_time(struct device * dev,struct rtc_time * tm)133 static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
134 {
135 struct goldfish_rtc *rtcdrv;
136 void __iomem *base;
137 u64 time_high;
138 u64 time_low;
139 u64 time;
140
141 rtcdrv = dev_get_drvdata(dev);
142 base = rtcdrv->base;
143
144 time_low = readl(base + TIMER_TIME_LOW);
145 time_high = readl(base + TIMER_TIME_HIGH);
146 time = (time_high << 32) | time_low;
147
148 do_div(time, NSEC_PER_SEC);
149
150 rtc_time_to_tm(time, tm);
151
152 return 0;
153 }
154
goldfish_rtc_set_time(struct device * dev,struct rtc_time * tm)155 static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
156 {
157 struct goldfish_rtc *rtcdrv;
158 void __iomem *base;
159 unsigned long now;
160 u64 now64;
161 int ret;
162
163 rtcdrv = dev_get_drvdata(dev);
164 base = rtcdrv->base;
165
166 ret = rtc_tm_to_time(tm, &now);
167 if (ret == 0) {
168 now64 = now * NSEC_PER_SEC;
169 writel((now64 >> 32), base + TIMER_TIME_HIGH);
170 writel(now64, base + TIMER_TIME_LOW);
171 }
172
173 return ret;
174 }
175
176 static const struct rtc_class_ops goldfish_rtc_ops = {
177 .read_time = goldfish_rtc_read_time,
178 .set_time = goldfish_rtc_set_time,
179 .read_alarm = goldfish_rtc_read_alarm,
180 .set_alarm = goldfish_rtc_set_alarm,
181 .alarm_irq_enable = goldfish_rtc_alarm_irq_enable
182 };
183
goldfish_rtc_probe(struct platform_device * pdev)184 static int goldfish_rtc_probe(struct platform_device *pdev)
185 {
186 struct goldfish_rtc *rtcdrv;
187 struct resource *r;
188 int err;
189
190 rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL);
191 if (!rtcdrv)
192 return -ENOMEM;
193
194 platform_set_drvdata(pdev, rtcdrv);
195
196 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
197 if (!r)
198 return -ENODEV;
199
200 rtcdrv->base = devm_ioremap_resource(&pdev->dev, r);
201 if (IS_ERR(rtcdrv->base))
202 return -ENODEV;
203
204 rtcdrv->irq = platform_get_irq(pdev, 0);
205 if (rtcdrv->irq < 0)
206 return -ENODEV;
207
208 rtcdrv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
209 &goldfish_rtc_ops,
210 THIS_MODULE);
211 if (IS_ERR(rtcdrv->rtc))
212 return PTR_ERR(rtcdrv->rtc);
213
214 err = devm_request_irq(&pdev->dev, rtcdrv->irq,
215 goldfish_rtc_interrupt,
216 0, pdev->name, rtcdrv);
217 if (err)
218 return err;
219
220 return 0;
221 }
222
223 static const struct of_device_id goldfish_rtc_of_match[] = {
224 { .compatible = "google,goldfish-rtc", },
225 {},
226 };
227 MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match);
228
229 static struct platform_driver goldfish_rtc = {
230 .probe = goldfish_rtc_probe,
231 .driver = {
232 .name = "goldfish_rtc",
233 .of_match_table = goldfish_rtc_of_match,
234 }
235 };
236
237 module_platform_driver(goldfish_rtc);
238
239 MODULE_LICENSE("GPL v2");
240
