linux/drivers/rtc/rtc-v3020.c
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   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
  35struct v3020 {
  36        void __iomem *ioaddress;
  37        int leftshift;
  38        struct rtc_device *rtc;
  39};
  40
  41static 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
  64static 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
  85static 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
 124static 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
 157static const struct rtc_class_ops v3020_rtc_ops = {
 158        .read_time      = v3020_read_time,
 159        .set_time       = v3020_set_time,
 160};
 161
 162static 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
 220err_io:
 221        iounmap(chip->ioaddress);
 222err_chip:
 223        kfree(chip);
 224
 225        return retval;
 226}
 227
 228static 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
 242static 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
 251static __init int v3020_init(void)
 252{
 253        return platform_driver_register(&rtc_device_driver);
 254}
 255
 256static __exit void v3020_exit(void)
 257{
 258        platform_driver_unregister(&rtc_device_driver);
 259}
 260
 261module_init(v3020_init);
 262module_exit(v3020_exit);
 263
 264MODULE_DESCRIPTION("V3020 RTC");
 265MODULE_AUTHOR("Raphael Assenat");
 266MODULE_LICENSE("GPL");
 267MODULE_ALIAS("platform:v3020");
 268
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