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 writel(1, base + TIMER_IRQ_ENABLED); 77 } else { 78 /* 79 * if this function was called with enabled=0 80 * then it could mean that the application is 81 * trying to cancel an ongoing alarm 82 */ 83 rtc_status_reg = readl(base + TIMER_ALARM_STATUS); 84 if (rtc_status_reg) 85 writel(1, base + TIMER_CLEAR_ALARM); 86 } 87 88 return 0; 89 } 90 91 static int goldfish_rtc_alarm_irq_enable(struct device *dev, 92 unsigned int enabled) 93 { 94 void __iomem *base; 95 struct goldfish_rtc *rtcdrv; 96 97 rtcdrv = dev_get_drvdata(dev); 98 base = rtcdrv->base; 99 100 if (enabled) 101 writel(1, base + TIMER_IRQ_ENABLED); 102 else 103 writel(0, base + TIMER_IRQ_ENABLED); 104 105 return 0; 106 } 107 108 static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id) 109 { 110 struct goldfish_rtc *rtcdrv = dev_id; 111 void __iomem *base = rtcdrv->base; 112 113 writel(1, base + TIMER_CLEAR_INTERRUPT); 114 115 rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF); 116 117 return IRQ_HANDLED; 118 } 119 120 static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm) 121 { 122 struct goldfish_rtc *rtcdrv; 123 void __iomem *base; 124 u64 time_high; 125 u64 time_low; 126 u64 time; 127 128 rtcdrv = dev_get_drvdata(dev); 129 base = rtcdrv->base; 130 131 time_low = readl(base + TIMER_TIME_LOW); 132 time_high = readl(base + TIMER_TIME_HIGH); 133 time = (time_high << 32) | time_low; 134 135 do_div(time, NSEC_PER_SEC); 136 137 rtc_time64_to_tm(time, tm); 138 139 return 0; 140 } 141 142 static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm) 143 { 144 struct goldfish_rtc *rtcdrv; 145 void __iomem *base; 146 u64 now64; 147 148 rtcdrv = dev_get_drvdata(dev); 149 base = rtcdrv->base; 150 151 now64 = rtc_tm_to_time64(tm) * NSEC_PER_SEC; 152 writel((now64 >> 32), base + TIMER_TIME_HIGH); 153 writel(now64, base + TIMER_TIME_LOW); 154 155 return 0; 156 } 157 158 static const struct rtc_class_ops goldfish_rtc_ops = { 159 .read_time = goldfish_rtc_read_time, 160 .set_time = goldfish_rtc_set_time, 161 .read_alarm = goldfish_rtc_read_alarm, 162 .set_alarm = goldfish_rtc_set_alarm, 163 .alarm_irq_enable = goldfish_rtc_alarm_irq_enable 164 }; 165 166 static int goldfish_rtc_probe(struct platform_device *pdev) 167 { 168 struct goldfish_rtc *rtcdrv; 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 rtcdrv->base = devm_platform_ioremap_resource(pdev, 0); 177 if (IS_ERR(rtcdrv->base)) 178 return PTR_ERR(rtcdrv->base); 179 180 rtcdrv->irq = platform_get_irq(pdev, 0); 181 if (rtcdrv->irq < 0) 182 return -ENODEV; 183 184 rtcdrv->rtc = devm_rtc_allocate_device(&pdev->dev); 185 if (IS_ERR(rtcdrv->rtc)) 186 return PTR_ERR(rtcdrv->rtc); 187 188 rtcdrv->rtc->ops = &goldfish_rtc_ops; 189 rtcdrv->rtc->range_max = U64_MAX / NSEC_PER_SEC; 190 191 err = devm_request_irq(&pdev->dev, rtcdrv->irq, 192 goldfish_rtc_interrupt, 193 0, pdev->name, rtcdrv); 194 if (err) 195 return err; 196 197 return rtc_register_device(rtcdrv->rtc); 198 } 199 200 static const struct of_device_id goldfish_rtc_of_match[] = { 201 { .compatible = "google,goldfish-rtc", }, 202 {}, 203 }; 204 MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match); 205 206 static struct platform_driver goldfish_rtc = { 207 .probe = goldfish_rtc_probe, 208 .driver = { 209 .name = "goldfish_rtc", 210 .of_match_table = goldfish_rtc_of_match, 211 } 212 }; 213 214 module_platform_driver(goldfish_rtc); 215 216 MODULE_LICENSE("GPL v2"); 217