1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/drivers/rtc/rtc-pl030.c 4 * 5 * Copyright (C) 2000-2001 Deep Blue Solutions Ltd. 6 */ 7 #include <linux/module.h> 8 #include <linux/rtc.h> 9 #include <linux/init.h> 10 #include <linux/interrupt.h> 11 #include <linux/amba/bus.h> 12 #include <linux/io.h> 13 #include <linux/slab.h> 14 15 #define RTC_DR (0) 16 #define RTC_MR (4) 17 #define RTC_STAT (8) 18 #define RTC_EOI (8) 19 #define RTC_LR (12) 20 #define RTC_CR (16) 21 #define RTC_CR_MIE (1 << 0) 22 23 struct pl030_rtc { 24 struct rtc_device *rtc; 25 void __iomem *base; 26 }; 27 28 static irqreturn_t pl030_interrupt(int irq, void *dev_id) 29 { 30 struct pl030_rtc *rtc = dev_id; 31 writel(0, rtc->base + RTC_EOI); 32 return IRQ_HANDLED; 33 } 34 35 static int pl030_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 36 { 37 struct pl030_rtc *rtc = dev_get_drvdata(dev); 38 39 rtc_time_to_tm(readl(rtc->base + RTC_MR), &alrm->time); 40 return 0; 41 } 42 43 static int pl030_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 44 { 45 struct pl030_rtc *rtc = dev_get_drvdata(dev); 46 unsigned long time; 47 int ret; 48 49 /* 50 * At the moment, we can only deal with non-wildcarded alarm times. 51 */ 52 ret = rtc_valid_tm(&alrm->time); 53 if (ret == 0) 54 ret = rtc_tm_to_time(&alrm->time, &time); 55 if (ret == 0) 56 writel(time, rtc->base + RTC_MR); 57 return ret; 58 } 59 60 static int pl030_read_time(struct device *dev, struct rtc_time *tm) 61 { 62 struct pl030_rtc *rtc = dev_get_drvdata(dev); 63 64 rtc_time_to_tm(readl(rtc->base + RTC_DR), tm); 65 66 return 0; 67 } 68 69 /* 70 * Set the RTC time. Unfortunately, we can't accurately set 71 * the point at which the counter updates. 72 * 73 * Also, since RTC_LR is transferred to RTC_CR on next rising 74 * edge of the 1Hz clock, we must write the time one second 75 * in advance. 76 */ 77 static int pl030_set_time(struct device *dev, struct rtc_time *tm) 78 { 79 struct pl030_rtc *rtc = dev_get_drvdata(dev); 80 unsigned long time; 81 int ret; 82 83 ret = rtc_tm_to_time(tm, &time); 84 if (ret == 0) 85 writel(time + 1, rtc->base + RTC_LR); 86 87 return ret; 88 } 89 90 static const struct rtc_class_ops pl030_ops = { 91 .read_time = pl030_read_time, 92 .set_time = pl030_set_time, 93 .read_alarm = pl030_read_alarm, 94 .set_alarm = pl030_set_alarm, 95 }; 96 97 static int pl030_probe(struct amba_device *dev, const struct amba_id *id) 98 { 99 struct pl030_rtc *rtc; 100 int ret; 101 102 ret = amba_request_regions(dev, NULL); 103 if (ret) 104 goto err_req; 105 106 rtc = devm_kzalloc(&dev->dev, sizeof(*rtc), GFP_KERNEL); 107 if (!rtc) { 108 ret = -ENOMEM; 109 goto err_rtc; 110 } 111 112 rtc->rtc = devm_rtc_allocate_device(&dev->dev); 113 if (IS_ERR(rtc->rtc)) { 114 ret = PTR_ERR(rtc->rtc); 115 goto err_rtc; 116 } 117 118 rtc->rtc->ops = &pl030_ops; 119 rtc->base = ioremap(dev->res.start, resource_size(&dev->res)); 120 if (!rtc->base) { 121 ret = -ENOMEM; 122 goto err_rtc; 123 } 124 125 __raw_writel(0, rtc->base + RTC_CR); 126 __raw_writel(0, rtc->base + RTC_EOI); 127 128 amba_set_drvdata(dev, rtc); 129 130 ret = request_irq(dev->irq[0], pl030_interrupt, 0, 131 "rtc-pl030", rtc); 132 if (ret) 133 goto err_irq; 134 135 ret = rtc_register_device(rtc->rtc); 136 if (ret) 137 goto err_reg; 138 139 return 0; 140 141 err_reg: 142 free_irq(dev->irq[0], rtc); 143 err_irq: 144 iounmap(rtc->base); 145 err_rtc: 146 amba_release_regions(dev); 147 err_req: 148 return ret; 149 } 150 151 static int pl030_remove(struct amba_device *dev) 152 { 153 struct pl030_rtc *rtc = amba_get_drvdata(dev); 154 155 writel(0, rtc->base + RTC_CR); 156 157 free_irq(dev->irq[0], rtc); 158 iounmap(rtc->base); 159 amba_release_regions(dev); 160 161 return 0; 162 } 163 164 static struct amba_id pl030_ids[] = { 165 { 166 .id = 0x00041030, 167 .mask = 0x000fffff, 168 }, 169 { 0, 0 }, 170 }; 171 172 MODULE_DEVICE_TABLE(amba, pl030_ids); 173 174 static struct amba_driver pl030_driver = { 175 .drv = { 176 .name = "rtc-pl030", 177 }, 178 .probe = pl030_probe, 179 .remove = pl030_remove, 180 .id_table = pl030_ids, 181 }; 182 183 module_amba_driver(pl030_driver); 184 185 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>"); 186 MODULE_DESCRIPTION("ARM AMBA PL030 RTC Driver"); 187 MODULE_LICENSE("GPL"); 188