1/* 2 * Dallas DS1216 RTC driver 3 * 4 * Copyright (c) 2007 Thomas Bogendoerfer 5 * 6 */ 7 8#include <linux/module.h> 9#include <linux/rtc.h> 10#include <linux/platform_device.h> 11#include <linux/bcd.h> 12#include <linux/slab.h> 13 14#define DRV_VERSION "0.2" 15 16struct ds1216_regs { 17 u8 tsec; 18 u8 sec; 19 u8 min; 20 u8 hour; 21 u8 wday; 22 u8 mday; 23 u8 month; 24 u8 year; 25}; 26 27#define DS1216_HOUR_1224 (1 << 7) 28#define DS1216_HOUR_AMPM (1 << 5) 29 30struct ds1216_priv { 31 struct rtc_device *rtc; 32 void __iomem *ioaddr; 33 size_t size; 34 unsigned long baseaddr; 35}; 36 37static const u8 magic[] = { 38 0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c 39}; 40 41/* 42 * Read the 64 bit we'd like to have - It a series 43 * of 64 bits showing up in the LSB of the base register. 44 * 45 */ 46static void ds1216_read(u8 __iomem *ioaddr, u8 *buf) 47{ 48 unsigned char c; 49 int i, j; 50 51 for (i = 0; i < 8; i++) { 52 c = 0; 53 for (j = 0; j < 8; j++) 54 c |= (readb(ioaddr) & 0x1) << j; 55 buf[i] = c; 56 } 57} 58 59static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf) 60{ 61 unsigned char c; 62 int i, j; 63 64 for (i = 0; i < 8; i++) { 65 c = buf[i]; 66 for (j = 0; j < 8; j++) { 67 writeb(c, ioaddr); 68 c = c >> 1; 69 } 70 } 71} 72 73static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr) 74{ 75 /* Reset magic pointer */ 76 readb(ioaddr); 77 /* Write 64 bit magic to DS1216 */ 78 ds1216_write(ioaddr, magic); 79} 80 81static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm) 82{ 83 struct platform_device *pdev = to_platform_device(dev); 84 struct ds1216_priv *priv = platform_get_drvdata(pdev); 85 struct ds1216_regs regs; 86 87 ds1216_switch_ds_to_clock(priv->ioaddr); 88 ds1216_read(priv->ioaddr, (u8 *)®s); 89 90 tm->tm_sec = bcd2bin(regs.sec); 91 tm->tm_min = bcd2bin(regs.min); 92 if (regs.hour & DS1216_HOUR_1224) { 93 /* AM/PM mode */ 94 tm->tm_hour = bcd2bin(regs.hour & 0x1f); 95 if (regs.hour & DS1216_HOUR_AMPM) 96 tm->tm_hour += 12; 97 } else 98 tm->tm_hour = bcd2bin(regs.hour & 0x3f); 99 tm->tm_wday = (regs.wday & 7) - 1; 100 tm->tm_mday = bcd2bin(regs.mday & 0x3f); 101 tm->tm_mon = bcd2bin(regs.month & 0x1f); 102 tm->tm_year = bcd2bin(regs.year); 103 if (tm->tm_year < 70) 104 tm->tm_year += 100; 105 106 return rtc_valid_tm(tm); 107} 108 109static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm) 110{ 111 struct platform_device *pdev = to_platform_device(dev); 112 struct ds1216_priv *priv = platform_get_drvdata(pdev); 113 struct ds1216_regs regs; 114 115 ds1216_switch_ds_to_clock(priv->ioaddr); 116 ds1216_read(priv->ioaddr, (u8 *)®s); 117 118 regs.tsec = 0; /* clear 0.1 and 0.01 seconds */ 119 regs.sec = bin2bcd(tm->tm_sec); 120 regs.min = bin2bcd(tm->tm_min); 121 regs.hour &= DS1216_HOUR_1224; 122 if (regs.hour && tm->tm_hour > 12) { 123 regs.hour |= DS1216_HOUR_AMPM; 124 tm->tm_hour -= 12; 125 } 126 regs.hour |= bin2bcd(tm->tm_hour); 127 regs.wday &= ~7; 128 regs.wday |= tm->tm_wday; 129 regs.mday = bin2bcd(tm->tm_mday); 130 regs.month = bin2bcd(tm->tm_mon); 131 regs.year = bin2bcd(tm->tm_year % 100); 132 133 ds1216_switch_ds_to_clock(priv->ioaddr); 134 ds1216_write(priv->ioaddr, (u8 *)®s); 135 return 0; 136} 137 138static const struct rtc_class_ops ds1216_rtc_ops = { 139 .read_time = ds1216_rtc_read_time, 140 .set_time = ds1216_rtc_set_time, 141}; 142 143static int __init ds1216_rtc_probe(struct platform_device *pdev) 144{ 145 struct resource *res; 146 struct ds1216_priv *priv; 147 int ret = 0; 148 u8 dummy[8]; 149 150 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 151 if (!res) 152 return -ENODEV; 153 priv = kzalloc(sizeof *priv, GFP_KERNEL); 154 if (!priv) 155 return -ENOMEM; 156 157 platform_set_drvdata(pdev, priv); 158 159 priv->size = resource_size(res); 160 if (!request_mem_region(res->start, priv->size, pdev->name)) { 161 ret = -EBUSY; 162 goto out; 163 } 164 priv->baseaddr = res->start; 165 priv->ioaddr = ioremap(priv->baseaddr, priv->size); 166 if (!priv->ioaddr) { 167 ret = -ENOMEM; 168 goto out; 169 } 170 priv->rtc = rtc_device_register("ds1216", &pdev->dev, 171 &ds1216_rtc_ops, THIS_MODULE); 172 if (IS_ERR(priv->rtc)) { 173 ret = PTR_ERR(priv->rtc); 174 goto out; 175 } 176 177 /* dummy read to get clock into a known state */ 178 ds1216_read(priv->ioaddr, dummy); 179 return 0; 180 181out: 182 if (priv->ioaddr) 183 iounmap(priv->ioaddr); 184 if (priv->baseaddr) 185 release_mem_region(priv->baseaddr, priv->size); 186 kfree(priv); 187 return ret; 188} 189 190static int __exit ds1216_rtc_remove(struct platform_device *pdev) 191{ 192 struct ds1216_priv *priv = platform_get_drvdata(pdev); 193 194 rtc_device_unregister(priv->rtc); 195 iounmap(priv->ioaddr); 196 release_mem_region(priv->baseaddr, priv->size); 197 kfree(priv); 198 return 0; 199} 200 201static struct platform_driver ds1216_rtc_platform_driver = { 202 .driver = { 203 .name = "rtc-ds1216", 204 .owner = THIS_MODULE, 205 }, 206 .remove = __exit_p(ds1216_rtc_remove), 207}; 208 209static int __init ds1216_rtc_init(void) 210{ 211 return platform_driver_probe(&ds1216_rtc_platform_driver, ds1216_rtc_probe); 212} 213 214static void __exit ds1216_rtc_exit(void) 215{ 216 platform_driver_unregister(&ds1216_rtc_platform_driver); 217} 218 219MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>"); 220MODULE_DESCRIPTION("DS1216 RTC driver"); 221MODULE_LICENSE("GPL"); 222MODULE_VERSION(DRV_VERSION); 223MODULE_ALIAS("platform:rtc-ds1216"); 224 225module_init(ds1216_rtc_init); 226module_exit(ds1216_rtc_exit); 227