drivers/rtc/rtc-v3020.c

   1 /* drivers/rtc/rtc-v3020.c
   2  *
   3  * Copyright (C) 2006 8D Technologies inc.
   4  * Copyright (C) 2004 Compulab Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Driver for the V3020 RTC
  11  *
  12  * Changelog:
  13  *
  14  *  10-May-2006: Raphael Assenat <raph@8d.com>
  15  *                              - Converted to platform driver
  16  *                              - Use the generic rtc class
  17  *
  18  *  ??-???-2004: Someone at Compulab
  19  *                      - Initial driver creation.
  20  *
  21  */
  22 #include <linux/platform_device.h>
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25 #include <linux/rtc.h>
  26 #include <linux/types.h>
  27 #include <linux/bcd.h>
  28 #include <linux/rtc-v3020.h>
  29 #include <linux/delay.h>
  30
  31 #include <asm/io.h>
  32
  33 #undef DEBUG
  34
  35 struct v3020 {
  36         void __iomem *ioaddress;
  37         int leftshift;
  38         struct rtc_device *rtc;
  39 };
  40
  41 static void v3020_set_reg(struct v3020 *chip, unsigned char address,
  42                         unsigned char data)
  43 {
  44         int i;
  45         unsigned char tmp;
  46
  47         tmp = address;
  48         for (i = 0; i < 4; i++) {
  49                 writel((tmp & 1) << chip->leftshift, chip->ioaddress);
  50                 tmp >>= 1;
  51                 udelay(1);
  52         }
  53
  54         /* Commands dont have data */
  55         if (!V3020_IS_COMMAND(address)) {
  56                 for (i = 0; i < 8; i++) {
  57                         writel((data & 1) << chip->leftshift, chip->ioaddress);
  58                         data >>= 1;
  59                         udelay(1);
  60                 }
  61         }
  62 }
  63
  64 static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
  65 {
  66         unsigned int data=0;
  67         int i;
  68
  69         for (i = 0; i < 4; i++) {
  70                 writel((address & 1) << chip->leftshift, chip->ioaddress);
  71                 address >>= 1;
  72                 udelay(1);
  73         }
  74
  75         for (i = 0; i < 8; i++) {
  76                 data >>= 1;
  77                 if (readl(chip->ioaddress) & (1 << chip->leftshift))
  78                         data |= 0x80;
  79                 udelay(1);
  80         }
  81
  82         return data;
  83 }
  84
  85 static int v3020_read_time(struct device *dev, struct rtc_time *dt)
  86 {
  87         struct v3020 *chip = dev_get_drvdata(dev);
  88         int tmp;
  89
  90         /* Copy the current time to ram... */
  91         v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);
  92
  93         /* ...and then read constant values. */
  94         tmp = v3020_get_reg(chip, V3020_SECONDS);
  95         dt->tm_sec      = BCD2BIN(tmp);
  96         tmp = v3020_get_reg(chip, V3020_MINUTES);
  97         dt->tm_min      = BCD2BIN(tmp);
  98         tmp = v3020_get_reg(chip, V3020_HOURS);
  99         dt->tm_hour     = BCD2BIN(tmp);
 100         tmp = v3020_get_reg(chip, V3020_MONTH_DAY);
 101         dt->tm_mday     = BCD2BIN(tmp);
 102         tmp = v3020_get_reg(chip, V3020_MONTH);
 103         dt->tm_mon    = BCD2BIN(tmp) - 1;
 104         tmp = v3020_get_reg(chip, V3020_WEEK_DAY);
 105         dt->tm_wday     = BCD2BIN(tmp);
 106         tmp = v3020_get_reg(chip, V3020_YEAR);
 107         dt->tm_year = BCD2BIN(tmp)+100;
 108
 109 #ifdef DEBUG
 110         printk("\n%s : Read RTC values\n",__func__);
 111         printk("tm_hour: %i\n",dt->tm_hour);
 112         printk("tm_min : %i\n",dt->tm_min);
 113         printk("tm_sec : %i\n",dt->tm_sec);
 114         printk("tm_year: %i\n",dt->tm_year);
 115         printk("tm_mon : %i\n",dt->tm_mon);
 116         printk("tm_mday: %i\n",dt->tm_mday);
 117         printk("tm_wday: %i\n",dt->tm_wday);
 118 #endif
 119
 120         return 0;
 121 }
 122
 123
 124 static int v3020_set_time(struct device *dev, struct rtc_time *dt)
 125 {
 126         struct v3020 *chip = dev_get_drvdata(dev);
 127
 128 #ifdef DEBUG
 129         printk("\n%s : Setting RTC values\n",__func__);
 130         printk("tm_sec : %i\n",dt->tm_sec);
 131         printk("tm_min : %i\n",dt->tm_min);
 132         printk("tm_hour: %i\n",dt->tm_hour);
 133         printk("tm_mday: %i\n",dt->tm_mday);
 134         printk("tm_wday: %i\n",dt->tm_wday);
 135         printk("tm_year: %i\n",dt->tm_year);
 136 #endif
 137
 138         /* Write all the values to ram... */
 139         v3020_set_reg(chip, V3020_SECONDS,      BIN2BCD(dt->tm_sec));
 140         v3020_set_reg(chip, V3020_MINUTES,      BIN2BCD(dt->tm_min));
 141         v3020_set_reg(chip, V3020_HOURS,        BIN2BCD(dt->tm_hour));
 142         v3020_set_reg(chip, V3020_MONTH_DAY,    BIN2BCD(dt->tm_mday));
 143         v3020_set_reg(chip, V3020_MONTH,     BIN2BCD(dt->tm_mon + 1));
 144         v3020_set_reg(chip, V3020_WEEK_DAY,     BIN2BCD(dt->tm_wday));
 145         v3020_set_reg(chip, V3020_YEAR,         BIN2BCD(dt->tm_year % 100));
 146
 147         /* ...and set the clock. */
 148         v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);
 149
 150         /* Compulab used this delay here. I dont know why,
 151          * the datasheet does not specify a delay. */
 152         /*mdelay(5);*/
 153
 154         return 0;
 155 }
 156
 157 static const struct rtc_class_ops v3020_rtc_ops = {
 158         .read_time      = v3020_read_time,
 159         .set_time       = v3020_set_time,
 160 };
 161
 162 static int rtc_probe(struct platform_device *pdev)
 163 {
 164         struct v3020_platform_data *pdata = pdev->dev.platform_data;
 165         struct v3020 *chip;
 166         struct rtc_device *rtc;
 167         int retval = -EBUSY;
 168         int i;
 169         int temp;
 170
 171         if (pdev->num_resources != 1)
 172                 return -EBUSY;
 173
 174         if (pdev->resource[0].flags != IORESOURCE_MEM)
 175                 return -EBUSY;
 176
 177         chip = kzalloc(sizeof *chip, GFP_KERNEL);
 178         if (!chip)
 179                 return -ENOMEM;
 180
 181         chip->leftshift = pdata->leftshift;
 182         chip->ioaddress = ioremap(pdev->resource[0].start, 1);
 183         if (chip->ioaddress == NULL)
 184                 goto err_chip;
 185
 186         /* Make sure the v3020 expects a communication cycle
 187          * by reading 8 times */
 188         for (i = 0; i < 8; i++)
 189                 temp = readl(chip->ioaddress);
 190
 191         /* Test chip by doing a write/read sequence
 192          * to the chip ram */
 193         v3020_set_reg(chip, V3020_SECONDS, 0x33);
 194         if(v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
 195                 retval = -ENODEV;
 196                 goto err_io;
 197         }
 198
 199         /* Make sure frequency measurment mode, test modes, and lock
 200          * are all disabled */
 201         v3020_set_reg(chip, V3020_STATUS_0, 0x0);
 202
 203         dev_info(&pdev->dev, "Chip available at physical address 0x%llx,"
 204                 "data connected to D%d\n",
 205                 (unsigned long long)pdev->resource[0].start,
 206                 chip->leftshift);
 207
 208         platform_set_drvdata(pdev, chip);
 209
 210         rtc = rtc_device_register("v3020",
 211                                 &pdev->dev, &v3020_rtc_ops, THIS_MODULE);
 212         if (IS_ERR(rtc)) {
 213                 retval = PTR_ERR(rtc);
 214                 goto err_io;
 215         }
 216         chip->rtc = rtc;
 217
 218         return 0;
 219
 220 err_io:
 221         iounmap(chip->ioaddress);
 222 err_chip:
 223         kfree(chip);
 224
 225         return retval;
 226 }
 227
 228 static int rtc_remove(struct platform_device *dev)
 229 {
 230         struct v3020 *chip = platform_get_drvdata(dev);
 231         struct rtc_device *rtc = chip->rtc;
 232
 233         if (rtc)
 234                 rtc_device_unregister(rtc);
 235
 236         iounmap(chip->ioaddress);
 237         kfree(chip);
 238
 239         return 0;
 240 }
 241
 242 static struct platform_driver rtc_device_driver = {
 243         .probe  = rtc_probe,
 244         .remove = rtc_remove,
 245         .driver = {
 246                 .name   = "v3020",
 247                 .owner  = THIS_MODULE,
 248         },
 249 };
 250
 251 static __init int v3020_init(void)
 252 {
 253         return platform_driver_register(&rtc_device_driver);
 254 }
 255
 256 static __exit void v3020_exit(void)
 257 {
 258         platform_driver_unregister(&rtc_device_driver);
 259 }
 260
 261 module_init(v3020_init);
 262 module_exit(v3020_exit);
 263
 264 MODULE_DESCRIPTION("V3020 RTC");
 265 MODULE_AUTHOR("Raphael Assenat");
 266 MODULE_LICENSE("GPL");
 267 MODULE_ALIAS("platform:v3020");