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 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 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 } 103 104 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 } 120 121 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 } 132 133 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 } 154 155 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 }; 183 184 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