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 "0.1" 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 return 0; 105 } 106 107 static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm) 108 { 109 struct platform_device *pdev = to_platform_device(dev); 110 struct ds1216_priv *priv = platform_get_drvdata(pdev); 111 struct ds1216_regs regs; 112 113 ds1216_switch_ds_to_clock(priv->ioaddr); 114 ds1216_read(priv->ioaddr, (u8 *)®s); 115 116 regs.tsec = 0; /* clear 0.1 and 0.01 seconds */ 117 regs.sec = BIN2BCD(tm->tm_sec); 118 regs.min = BIN2BCD(tm->tm_min); 119 regs.hour &= DS1216_HOUR_1224; 120 if (regs.hour && tm->tm_hour > 12) { 121 regs.hour |= DS1216_HOUR_AMPM; 122 tm->tm_hour -= 12; 123 } 124 regs.hour |= BIN2BCD(tm->tm_hour); 125 regs.wday &= ~7; 126 regs.wday |= tm->tm_wday; 127 regs.mday = BIN2BCD(tm->tm_mday); 128 regs.month = BIN2BCD(tm->tm_mon); 129 regs.year = BIN2BCD(tm->tm_year % 100); 130 131 ds1216_switch_ds_to_clock(priv->ioaddr); 132 ds1216_write(priv->ioaddr, (u8 *)®s); 133 return 0; 134 } 135 136 static const struct rtc_class_ops ds1216_rtc_ops = { 137 .read_time = ds1216_rtc_read_time, 138 .set_time = ds1216_rtc_set_time, 139 }; 140 141 static int __devinit ds1216_rtc_probe(struct platform_device *pdev) 142 { 143 struct rtc_device *rtc; 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 priv->size = res->end - res->start + 1; 156 if (!request_mem_region(res->start, priv->size, pdev->name)) { 157 ret = -EBUSY; 158 goto out; 159 } 160 priv->baseaddr = res->start; 161 priv->ioaddr = ioremap(priv->baseaddr, priv->size); 162 if (!priv->ioaddr) { 163 ret = -ENOMEM; 164 goto out; 165 } 166 rtc = rtc_device_register("ds1216", &pdev->dev, 167 &ds1216_rtc_ops, THIS_MODULE); 168 if (IS_ERR(rtc)) { 169 ret = PTR_ERR(rtc); 170 goto out; 171 } 172 priv->rtc = rtc; 173 platform_set_drvdata(pdev, priv); 174 175 /* dummy read to get clock into a known state */ 176 ds1216_read(priv->ioaddr, dummy); 177 return 0; 178 179 out: 180 if (priv->rtc) 181 rtc_device_unregister(priv->rtc); 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 } 189 190 static int __devexit 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 } 200 201 static struct platform_driver ds1216_rtc_platform_driver = { 202 .driver = { 203 .name = "rtc-ds1216", 204 .owner = THIS_MODULE, 205 }, 206 .probe = ds1216_rtc_probe, 207 .remove = __devexit_p(ds1216_rtc_remove), 208 }; 209 210 static int __init ds1216_rtc_init(void) 211 { 212 return platform_driver_register(&ds1216_rtc_platform_driver); 213 } 214 215 static void __exit ds1216_rtc_exit(void) 216 { 217 platform_driver_unregister(&ds1216_rtc_platform_driver); 218 } 219 220 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>"); 221 MODULE_DESCRIPTION("DS1216 RTC driver"); 222 MODULE_LICENSE("GPL"); 223 MODULE_VERSION(DRV_VERSION); 224 225 module_init(ds1216_rtc_init); 226 module_exit(ds1216_rtc_exit); 227