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