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/platform_data/rtc-v3020.h>
  29#include <linux/delay.h>
  30#include <linux/gpio.h>
  31#include <linux/slab.h>
  32
  33#include <linux/io.h>
  34
  35#undef DEBUG
  36
  37struct v3020;
  38
  39struct v3020_chip_ops {
  40        int (*map_io)(struct v3020 *chip, struct platform_device *pdev,
  41                      struct v3020_platform_data *pdata);
  42        void (*unmap_io)(struct v3020 *chip);
  43        unsigned char (*read_bit)(struct v3020 *chip);
  44        void (*write_bit)(struct v3020 *chip, unsigned char bit);
  45};
  46
  47#define V3020_CS        0
  48#define V3020_WR        1
  49#define V3020_RD        2
  50#define V3020_IO        3
  51
  52struct v3020 {
  53        /* MMIO access */
  54        void __iomem *ioaddress;
  55        int leftshift;
  56
  57        /* GPIO access */
  58        struct gpio *gpio;
  59
  60        const struct v3020_chip_ops *ops;
  61
  62        struct rtc_device *rtc;
  63};
  64
  65
  66static int v3020_mmio_map(struct v3020 *chip, struct platform_device *pdev,
  67                          struct v3020_platform_data *pdata)
  68{
  69        if (pdev->num_resources != 1)
  70                return -EBUSY;
  71
  72        if (pdev->resource[0].flags != IORESOURCE_MEM)
  73                return -EBUSY;
  74
  75        chip->leftshift = pdata->leftshift;
  76        chip->ioaddress = ioremap(pdev->resource[0].start, 1);
  77        if (chip->ioaddress == NULL)
  78                return -EBUSY;
  79
  80        return 0;
  81}
  82
  83static void v3020_mmio_unmap(struct v3020 *chip)
  84{
  85        iounmap(chip->ioaddress);
  86}
  87
  88static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
  89{
  90        writel(bit << chip->leftshift, chip->ioaddress);
  91}
  92
  93static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
  94{
  95        return !!(readl(chip->ioaddress) & (1 << chip->leftshift));
  96}
  97
  98static const struct v3020_chip_ops v3020_mmio_ops = {
  99        .map_io         = v3020_mmio_map,
 100        .unmap_io       = v3020_mmio_unmap,
 101        .read_bit       = v3020_mmio_read_bit,
 102        .write_bit      = v3020_mmio_write_bit,
 103};
 104
 105static struct gpio v3020_gpio[] = {
 106        { 0, GPIOF_OUT_INIT_HIGH, "RTC CS"},
 107        { 0, GPIOF_OUT_INIT_HIGH, "RTC WR"},
 108        { 0, GPIOF_OUT_INIT_HIGH, "RTC RD"},
 109        { 0, GPIOF_OUT_INIT_HIGH, "RTC IO"},
 110};
 111
 112static int v3020_gpio_map(struct v3020 *chip, struct platform_device *pdev,
 113                          struct v3020_platform_data *pdata)
 114{
 115        int err;
 116
 117        v3020_gpio[V3020_CS].gpio = pdata->gpio_cs;
 118        v3020_gpio[V3020_WR].gpio = pdata->gpio_wr;
 119        v3020_gpio[V3020_RD].gpio = pdata->gpio_rd;
 120        v3020_gpio[V3020_IO].gpio = pdata->gpio_io;
 121
 122        err = gpio_request_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
 123
 124        if (!err)
 125                chip->gpio = v3020_gpio;
 126
 127        return err;
 128}
 129
 130static void v3020_gpio_unmap(struct v3020 *chip)
 131{
 132        gpio_free_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
 133}
 134
 135static void v3020_gpio_write_bit(struct v3020 *chip, unsigned char bit)
 136{
 137        gpio_direction_output(chip->gpio[V3020_IO].gpio, bit);
 138        gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
 139        gpio_set_value(chip->gpio[V3020_WR].gpio, 0);
 140        udelay(1);
 141        gpio_set_value(chip->gpio[V3020_WR].gpio, 1);
 142        gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
 143}
 144
 145static unsigned char v3020_gpio_read_bit(struct v3020 *chip)
 146{
 147        int bit;
 148
 149        gpio_direction_input(chip->gpio[V3020_IO].gpio);
 150        gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
 151        gpio_set_value(chip->gpio[V3020_RD].gpio, 0);
 152        udelay(1);
 153        bit = !!gpio_get_value(chip->gpio[V3020_IO].gpio);
 154        udelay(1);
 155        gpio_set_value(chip->gpio[V3020_RD].gpio, 1);
 156        gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
 157
 158        return bit;
 159}
 160
 161static const struct v3020_chip_ops v3020_gpio_ops = {
 162        .map_io         = v3020_gpio_map,
 163        .unmap_io       = v3020_gpio_unmap,
 164        .read_bit       = v3020_gpio_read_bit,
 165        .write_bit      = v3020_gpio_write_bit,
 166};
 167
 168static void v3020_set_reg(struct v3020 *chip, unsigned char address,
 169                        unsigned char data)
 170{
 171        int i;
 172        unsigned char tmp;
 173
 174        tmp = address;
 175        for (i = 0; i < 4; i++) {
 176                chip->ops->write_bit(chip, (tmp & 1));
 177                tmp >>= 1;
 178                udelay(1);
 179        }
 180
 181        /* Commands dont have data */
 182        if (!V3020_IS_COMMAND(address)) {
 183                for (i = 0; i < 8; i++) {
 184                        chip->ops->write_bit(chip, (data & 1));
 185                        data >>= 1;
 186                        udelay(1);
 187                }
 188        }
 189}
 190
 191static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
 192{
 193        unsigned int data = 0;
 194        int i;
 195
 196        for (i = 0; i < 4; i++) {
 197                chip->ops->write_bit(chip, (address & 1));
 198                address >>= 1;
 199                udelay(1);
 200        }
 201
 202        for (i = 0; i < 8; i++) {
 203                data >>= 1;
 204                if (chip->ops->read_bit(chip))
 205                        data |= 0x80;
 206                udelay(1);
 207        }
 208
 209        return data;
 210}
 211
 212static int v3020_read_time(struct device *dev, struct rtc_time *dt)
 213{
 214        struct v3020 *chip = dev_get_drvdata(dev);
 215        int tmp;
 216
 217        /* Copy the current time to ram... */
 218        v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);
 219
 220        /* ...and then read constant values. */
 221        tmp = v3020_get_reg(chip, V3020_SECONDS);
 222        dt->tm_sec      = bcd2bin(tmp);
 223        tmp = v3020_get_reg(chip, V3020_MINUTES);
 224        dt->tm_min      = bcd2bin(tmp);
 225        tmp = v3020_get_reg(chip, V3020_HOURS);
 226        dt->tm_hour     = bcd2bin(tmp);
 227        tmp = v3020_get_reg(chip, V3020_MONTH_DAY);
 228        dt->tm_mday     = bcd2bin(tmp);
 229        tmp = v3020_get_reg(chip, V3020_MONTH);
 230        dt->tm_mon    = bcd2bin(tmp) - 1;
 231        tmp = v3020_get_reg(chip, V3020_WEEK_DAY);
 232        dt->tm_wday     = bcd2bin(tmp);
 233        tmp = v3020_get_reg(chip, V3020_YEAR);
 234        dt->tm_year = bcd2bin(tmp)+100;
 235
 236        dev_dbg(dev, "\n%s : Read RTC values\n", __func__);
 237        dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
 238        dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
 239        dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
 240        dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
 241        dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
 242        dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
 243        dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
 244
 245        return 0;
 246}
 247
 248
 249static int v3020_set_time(struct device *dev, struct rtc_time *dt)
 250{
 251        struct v3020 *chip = dev_get_drvdata(dev);
 252
 253        dev_dbg(dev, "\n%s : Setting RTC values\n", __func__);
 254        dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
 255        dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
 256        dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
 257        dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
 258        dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
 259        dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
 260
 261        /* Write all the values to ram... */
 262        v3020_set_reg(chip, V3020_SECONDS,      bin2bcd(dt->tm_sec));
 263        v3020_set_reg(chip, V3020_MINUTES,      bin2bcd(dt->tm_min));
 264        v3020_set_reg(chip, V3020_HOURS,        bin2bcd(dt->tm_hour));
 265        v3020_set_reg(chip, V3020_MONTH_DAY,    bin2bcd(dt->tm_mday));
 266        v3020_set_reg(chip, V3020_MONTH,        bin2bcd(dt->tm_mon + 1));
 267        v3020_set_reg(chip, V3020_WEEK_DAY,     bin2bcd(dt->tm_wday));
 268        v3020_set_reg(chip, V3020_YEAR,         bin2bcd(dt->tm_year % 100));
 269
 270        /* ...and set the clock. */
 271        v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);
 272
 273        /* Compulab used this delay here. I dont know why,
 274         * the datasheet does not specify a delay. */
 275        /*mdelay(5);*/
 276
 277        return 0;
 278}
 279
 280static const struct rtc_class_ops v3020_rtc_ops = {
 281        .read_time      = v3020_read_time,
 282        .set_time       = v3020_set_time,
 283};
 284
 285static int rtc_probe(struct platform_device *pdev)
 286{
 287        struct v3020_platform_data *pdata = dev_get_platdata(&pdev->dev);
 288        struct v3020 *chip;
 289        int retval = -EBUSY;
 290        int i;
 291        int temp;
 292
 293        chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
 294        if (!chip)
 295                return -ENOMEM;
 296
 297        if (pdata->use_gpio)
 298                chip->ops = &v3020_gpio_ops;
 299        else
 300                chip->ops = &v3020_mmio_ops;
 301
 302        retval = chip->ops->map_io(chip, pdev, pdata);
 303        if (retval)
 304                return retval;
 305
 306        /* Make sure the v3020 expects a communication cycle
 307         * by reading 8 times */
 308        for (i = 0; i < 8; i++)
 309                temp = chip->ops->read_bit(chip);
 310
 311        /* Test chip by doing a write/read sequence
 312         * to the chip ram */
 313        v3020_set_reg(chip, V3020_SECONDS, 0x33);
 314        if (v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
 315                retval = -ENODEV;
 316                goto err_io;
 317        }
 318
 319        /* Make sure frequency measurement mode, test modes, and lock
 320         * are all disabled */
 321        v3020_set_reg(chip, V3020_STATUS_0, 0x0);
 322
 323        if (pdata->use_gpio)
 324                dev_info(&pdev->dev, "Chip available at GPIOs "
 325                         "%d, %d, %d, %d\n",
 326                         chip->gpio[V3020_CS].gpio, chip->gpio[V3020_WR].gpio,
 327                         chip->gpio[V3020_RD].gpio, chip->gpio[V3020_IO].gpio);
 328        else
 329                dev_info(&pdev->dev, "Chip available at "
 330                         "physical address 0x%llx,"
 331                         "data connected to D%d\n",
 332                         (unsigned long long)pdev->resource[0].start,
 333                         chip->leftshift);
 334
 335        platform_set_drvdata(pdev, chip);
 336
 337        chip->rtc = devm_rtc_device_register(&pdev->dev, "v3020",
 338                                        &v3020_rtc_ops, THIS_MODULE);
 339        if (IS_ERR(chip->rtc)) {
 340                retval = PTR_ERR(chip->rtc);
 341                goto err_io;
 342        }
 343
 344        return 0;
 345
 346err_io:
 347        chip->ops->unmap_io(chip);
 348
 349        return retval;
 350}
 351
 352static int rtc_remove(struct platform_device *dev)
 353{
 354        struct v3020 *chip = platform_get_drvdata(dev);
 355
 356        chip->ops->unmap_io(chip);
 357
 358        return 0;
 359}
 360
 361static struct platform_driver rtc_device_driver = {
 362        .probe  = rtc_probe,
 363        .remove = rtc_remove,
 364        .driver = {
 365                .name   = "v3020",
 366        },
 367};
 368
 369module_platform_driver(rtc_device_driver);
 370
 371MODULE_DESCRIPTION("V3020 RTC");
 372MODULE_AUTHOR("Raphael Assenat");
 373MODULE_LICENSE("GPL");
 374MODULE_ALIAS("platform:v3020");
 375