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_time64_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 47 writel(rtc_tm_to_time64(&alrm->time), rtc->base + RTC_MR); 48 49 return 0; 50 } 51 52 static int pl030_read_time(struct device *dev, struct rtc_time *tm) 53 { 54 struct pl030_rtc *rtc = dev_get_drvdata(dev); 55 56 rtc_time64_to_tm(readl(rtc->base + RTC_DR), tm); 57 58 return 0; 59 } 60 61 /* 62 * Set the RTC time. Unfortunately, we can't accurately set 63 * the point at which the counter updates. 64 * 65 * Also, since RTC_LR is transferred to RTC_CR on next rising 66 * edge of the 1Hz clock, we must write the time one second 67 * in advance. 68 */ 69 static int pl030_set_time(struct device *dev, struct rtc_time *tm) 70 { 71 struct pl030_rtc *rtc = dev_get_drvdata(dev); 72 73 writel(rtc_tm_to_time64(tm) + 1, rtc->base + RTC_LR); 74 75 return 0; 76 } 77 78 static const struct rtc_class_ops pl030_ops = { 79 .read_time = pl030_read_time, 80 .set_time = pl030_set_time, 81 .read_alarm = pl030_read_alarm, 82 .set_alarm = pl030_set_alarm, 83 }; 84 85 static int pl030_probe(struct amba_device *dev, const struct amba_id *id) 86 { 87 struct pl030_rtc *rtc; 88 int ret; 89 90 ret = amba_request_regions(dev, NULL); 91 if (ret) 92 goto err_req; 93 94 rtc = devm_kzalloc(&dev->dev, sizeof(*rtc), GFP_KERNEL); 95 if (!rtc) { 96 ret = -ENOMEM; 97 goto err_rtc; 98 } 99 100 rtc->rtc = devm_rtc_allocate_device(&dev->dev); 101 if (IS_ERR(rtc->rtc)) { 102 ret = PTR_ERR(rtc->rtc); 103 goto err_rtc; 104 } 105 106 rtc->rtc->ops = &pl030_ops; 107 rtc->rtc->range_max = U32_MAX; 108 rtc->base = ioremap(dev->res.start, resource_size(&dev->res)); 109 if (!rtc->base) { 110 ret = -ENOMEM; 111 goto err_rtc; 112 } 113 114 __raw_writel(0, rtc->base + RTC_CR); 115 __raw_writel(0, rtc->base + RTC_EOI); 116 117 amba_set_drvdata(dev, rtc); 118 119 ret = request_irq(dev->irq[0], pl030_interrupt, 0, 120 "rtc-pl030", rtc); 121 if (ret) 122 goto err_irq; 123 124 ret = devm_rtc_register_device(rtc->rtc); 125 if (ret) 126 goto err_reg; 127 128 return 0; 129 130 err_reg: 131 free_irq(dev->irq[0], rtc); 132 err_irq: 133 iounmap(rtc->base); 134 err_rtc: 135 amba_release_regions(dev); 136 err_req: 137 return ret; 138 } 139 140 static int pl030_remove(struct amba_device *dev) 141 { 142 struct pl030_rtc *rtc = amba_get_drvdata(dev); 143 144 writel(0, rtc->base + RTC_CR); 145 146 free_irq(dev->irq[0], rtc); 147 iounmap(rtc->base); 148 amba_release_regions(dev); 149 150 return 0; 151 } 152 153 static struct amba_id pl030_ids[] = { 154 { 155 .id = 0x00041030, 156 .mask = 0x000fffff, 157 }, 158 { 0, 0 }, 159 }; 160 161 MODULE_DEVICE_TABLE(amba, pl030_ids); 162 163 static struct amba_driver pl030_driver = { 164 .drv = { 165 .name = "rtc-pl030", 166 }, 167 .probe = pl030_probe, 168 .remove = pl030_remove, 169 .id_table = pl030_ids, 170 }; 171 172 module_amba_driver(pl030_driver); 173 174 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>"); 175 MODULE_DESCRIPTION("ARM AMBA PL030 RTC Driver"); 176 MODULE_LICENSE("GPL"); 177