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