1 /* 2 * Driver for the SGS-Thomson M48T35 Timekeeper RAM chip 3 * 4 * Copyright (C) 2000 Silicon Graphics, Inc. 5 * Written by Ulf Carlsson (ulfc@engr.sgi.com) 6 * 7 * Copyright (C) 2008 Thomas Bogendoerfer 8 * 9 * Based on code written by Paul Gortmaker. 10 * 11 * This program is free software; you can redistribute it and/or modify it 12 * under the terms of the GNU General Public License as published by the 13 * Free Software Foundation; either version 2 of the License, or (at your 14 * option) any later version. 15 */ 16 17 #include <linux/module.h> 18 #include <linux/rtc.h> 19 #include <linux/platform_device.h> 20 #include <linux/bcd.h> 21 22 #define DRV_VERSION "1.0" 23 24 struct m48t35_rtc { 25 u8 pad[0x7ff8]; /* starts at 0x7ff8 */ 26 u8 control; 27 u8 sec; 28 u8 min; 29 u8 hour; 30 u8 day; 31 u8 date; 32 u8 month; 33 u8 year; 34 }; 35 36 #define M48T35_RTC_SET 0x80 37 #define M48T35_RTC_READ 0x40 38 39 struct m48t35_priv { 40 struct rtc_device *rtc; 41 struct m48t35_rtc __iomem *reg; 42 size_t size; 43 unsigned long baseaddr; 44 spinlock_t lock; 45 }; 46 47 static int m48t35_read_time(struct device *dev, struct rtc_time *tm) 48 { 49 struct m48t35_priv *priv = dev_get_drvdata(dev); 50 u8 control; 51 52 /* 53 * Only the values that we read from the RTC are set. We leave 54 * tm_wday, tm_yday and tm_isdst untouched. Even though the 55 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated 56 * by the RTC when initially set to a non-zero value. 57 */ 58 spin_lock_irq(&priv->lock); 59 control = readb(&priv->reg->control); 60 writeb(control | M48T35_RTC_READ, &priv->reg->control); 61 tm->tm_sec = readb(&priv->reg->sec); 62 tm->tm_min = readb(&priv->reg->min); 63 tm->tm_hour = readb(&priv->reg->hour); 64 tm->tm_mday = readb(&priv->reg->date); 65 tm->tm_mon = readb(&priv->reg->month); 66 tm->tm_year = readb(&priv->reg->year); 67 writeb(control, &priv->reg->control); 68 spin_unlock_irq(&priv->lock); 69 70 tm->tm_sec = bcd2bin(tm->tm_sec); 71 tm->tm_min = bcd2bin(tm->tm_min); 72 tm->tm_hour = bcd2bin(tm->tm_hour); 73 tm->tm_mday = bcd2bin(tm->tm_mday); 74 tm->tm_mon = bcd2bin(tm->tm_mon); 75 tm->tm_year = bcd2bin(tm->tm_year); 76 77 /* 78 * Account for differences between how the RTC uses the values 79 * and how they are defined in a struct rtc_time; 80 */ 81 tm->tm_year += 70; 82 if (tm->tm_year <= 69) 83 tm->tm_year += 100; 84 85 tm->tm_mon--; 86 return rtc_valid_tm(tm); 87 } 88 89 static int m48t35_set_time(struct device *dev, struct rtc_time *tm) 90 { 91 struct m48t35_priv *priv = dev_get_drvdata(dev); 92 unsigned char mon, day, hrs, min, sec; 93 unsigned int yrs; 94 u8 control; 95 96 yrs = tm->tm_year + 1900; 97 mon = tm->tm_mon + 1; /* tm_mon starts at zero */ 98 day = tm->tm_mday; 99 hrs = tm->tm_hour; 100 min = tm->tm_min; 101 sec = tm->tm_sec; 102 103 if (yrs < 1970) 104 return -EINVAL; 105 106 yrs -= 1970; 107 if (yrs > 255) /* They are unsigned */ 108 return -EINVAL; 109 110 if (yrs > 169) 111 return -EINVAL; 112 113 if (yrs >= 100) 114 yrs -= 100; 115 116 sec = bin2bcd(sec); 117 min = bin2bcd(min); 118 hrs = bin2bcd(hrs); 119 day = bin2bcd(day); 120 mon = bin2bcd(mon); 121 yrs = bin2bcd(yrs); 122 123 spin_lock_irq(&priv->lock); 124 control = readb(&priv->reg->control); 125 writeb(control | M48T35_RTC_SET, &priv->reg->control); 126 writeb(yrs, &priv->reg->year); 127 writeb(mon, &priv->reg->month); 128 writeb(day, &priv->reg->date); 129 writeb(hrs, &priv->reg->hour); 130 writeb(min, &priv->reg->min); 131 writeb(sec, &priv->reg->sec); 132 writeb(control, &priv->reg->control); 133 spin_unlock_irq(&priv->lock); 134 return 0; 135 } 136 137 static const struct rtc_class_ops m48t35_ops = { 138 .read_time = m48t35_read_time, 139 .set_time = m48t35_set_time, 140 }; 141 142 static int __devinit m48t35_probe(struct platform_device *pdev) 143 { 144 struct rtc_device *rtc; 145 struct resource *res; 146 struct m48t35_priv *priv; 147 int ret = 0; 148 149 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 150 if (!res) 151 return -ENODEV; 152 priv = kzalloc(sizeof(struct m48t35_priv), GFP_KERNEL); 153 if (!priv) 154 return -ENOMEM; 155 156 priv->size = res->end - res->start + 1; 157 /* 158 * kludge: remove the #ifndef after ioc3 resource 159 * conflicts are resolved 160 */ 161 #ifndef CONFIG_SGI_IP27 162 if (!request_mem_region(res->start, priv->size, pdev->name)) { 163 ret = -EBUSY; 164 goto out; 165 } 166 #endif 167 priv->baseaddr = res->start; 168 priv->reg = ioremap(priv->baseaddr, priv->size); 169 if (!priv->reg) { 170 ret = -ENOMEM; 171 goto out; 172 } 173 spin_lock_init(&priv->lock); 174 rtc = rtc_device_register("m48t35", &pdev->dev, 175 &m48t35_ops, THIS_MODULE); 176 if (IS_ERR(rtc)) { 177 ret = PTR_ERR(rtc); 178 goto out; 179 } 180 priv->rtc = rtc; 181 platform_set_drvdata(pdev, priv); 182 return 0; 183 184 out: 185 if (priv->rtc) 186 rtc_device_unregister(priv->rtc); 187 if (priv->reg) 188 iounmap(priv->reg); 189 if (priv->baseaddr) 190 release_mem_region(priv->baseaddr, priv->size); 191 kfree(priv); 192 return ret; 193 } 194 195 static int __devexit m48t35_remove(struct platform_device *pdev) 196 { 197 struct m48t35_priv *priv = platform_get_drvdata(pdev); 198 199 rtc_device_unregister(priv->rtc); 200 iounmap(priv->reg); 201 #ifndef CONFIG_SGI_IP27 202 release_mem_region(priv->baseaddr, priv->size); 203 #endif 204 kfree(priv); 205 return 0; 206 } 207 208 static struct platform_driver m48t35_platform_driver = { 209 .driver = { 210 .name = "rtc-m48t35", 211 .owner = THIS_MODULE, 212 }, 213 .probe = m48t35_probe, 214 .remove = __devexit_p(m48t35_remove), 215 }; 216 217 static int __init m48t35_init(void) 218 { 219 return platform_driver_register(&m48t35_platform_driver); 220 } 221 222 static void __exit m48t35_exit(void) 223 { 224 platform_driver_unregister(&m48t35_platform_driver); 225 } 226 227 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>"); 228 MODULE_DESCRIPTION("M48T35 RTC driver"); 229 MODULE_LICENSE("GPL"); 230 MODULE_VERSION(DRV_VERSION); 231 MODULE_ALIAS("platform:rtc-m48t35"); 232 233 module_init(m48t35_init); 234 module_exit(m48t35_exit); 235