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#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_gpio {
  53        const char *name;
  54        unsigned int gpio;
  55};
  56
  57struct v3020 {
  58        /* MMIO access */
  59        void __iomem *ioaddress;
  60        int leftshift;
  61
  62        /* GPIO access */
  63        struct v3020_gpio *gpio;
  64
  65        struct v3020_chip_ops *ops;
  66
  67        struct rtc_device *rtc;
  68};
  69
  70
  71static int v3020_mmio_map(struct v3020 *chip, struct platform_device *pdev,
  72                          struct v3020_platform_data *pdata)
  73{
  74        if (pdev->num_resources != 1)
  75                return -EBUSY;
  76
  77        if (pdev->resource[0].flags != IORESOURCE_MEM)
  78                return -EBUSY;
  79
  80        chip->leftshift = pdata->leftshift;
  81        chip->ioaddress = ioremap(pdev->resource[0].start, 1);
  82        if (chip->ioaddress == NULL)
  83                return -EBUSY;
  84
  85        return 0;
  86}
  87
  88static void v3020_mmio_unmap(struct v3020 *chip)
  89{
  90        iounmap(chip->ioaddress);
  91}
  92
  93static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
  94{
  95        writel(bit << chip->leftshift, chip->ioaddress);
  96}
  97
  98static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
  99{
 100        return !!(readl(chip->ioaddress) & (1 << chip->leftshift));
 101}
 102
 103static struct v3020_chip_ops v3020_mmio_ops = {
 104        .map_io         = v3020_mmio_map,
 105        .unmap_io       = v3020_mmio_unmap,
 106        .read_bit       = v3020_mmio_read_bit,
 107        .write_bit      = v3020_mmio_write_bit,
 108};
 109
 110static struct v3020_gpio v3020_gpio[] = {
 111        { "RTC CS", 0 },
 112        { "RTC WR", 0 },
 113        { "RTC RD", 0 },
 114        { "RTC IO", 0 },
 115};
 116
 117static int v3020_gpio_map(struct v3020 *chip, struct platform_device *pdev,
 118                          struct v3020_platform_data *pdata)
 119{
 120        int i, err;
 121
 122        v3020_gpio[V3020_CS].gpio = pdata->gpio_cs;
 123        v3020_gpio[V3020_WR].gpio = pdata->gpio_wr;
 124        v3020_gpio[V3020_RD].gpio = pdata->gpio_rd;
 125        v3020_gpio[V3020_IO].gpio = pdata->gpio_io;
 126
 127        for (i = 0; i < ARRAY_SIZE(v3020_gpio); i++) {
 128                err = gpio_request(v3020_gpio[i].gpio, v3020_gpio[i].name);
 129                if (err)
 130                        goto err_request;
 131
 132                gpio_direction_output(v3020_gpio[i].gpio, 1);
 133        }
 134
 135        chip->gpio = v3020_gpio;
 136
 137        return 0;
 138
 139err_request:
 140        while (--i >= 0)
 141                gpio_free(v3020_gpio[i].gpio);
 142
 143        return err;
 144}
 145
 146static void v3020_gpio_unmap(struct v3020 *chip)
 147{
 148        int i;
 149
 150        for (i = 0; i < ARRAY_SIZE(v3020_gpio); i++)
 151                gpio_free(v3020_gpio[i].gpio);
 152}
 153
 154static void v3020_gpio_write_bit(struct v3020 *chip, unsigned char bit)
 155{
 156        gpio_direction_output(chip->gpio[V3020_IO].gpio, bit);
 157        gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
 158        gpio_set_value(chip->gpio[V3020_WR].gpio, 0);
 159        udelay(1);
 160        gpio_set_value(chip->gpio[V3020_WR].gpio, 1);
 161        gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
 162}
 163
 164static unsigned char v3020_gpio_read_bit(struct v3020 *chip)
 165{
 166        int bit;
 167
 168        gpio_direction_input(chip->gpio[V3020_IO].gpio);
 169        gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
 170        gpio_set_value(chip->gpio[V3020_RD].gpio, 0);
 171        udelay(1);
 172        bit = !!gpio_get_value(chip->gpio[V3020_IO].gpio);
 173        udelay(1);
 174        gpio_set_value(chip->gpio[V3020_RD].gpio, 1);
 175        gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
 176
 177        return bit;
 178}
 179
 180static struct v3020_chip_ops v3020_gpio_ops = {
 181        .map_io         = v3020_gpio_map,
 182        .unmap_io       = v3020_gpio_unmap,
 183        .read_bit       = v3020_gpio_read_bit,
 184        .write_bit      = v3020_gpio_write_bit,
 185};
 186
 187static void v3020_set_reg(struct v3020 *chip, unsigned char address,
 188                        unsigned char data)
 189{
 190        int i;
 191        unsigned char tmp;
 192
 193        tmp = address;
 194        for (i = 0; i < 4; i++) {
 195                chip->ops->write_bit(chip, (tmp & 1));
 196                tmp >>= 1;
 197                udelay(1);
 198        }
 199
 200        /* Commands dont have data */
 201        if (!V3020_IS_COMMAND(address)) {
 202                for (i = 0; i < 8; i++) {
 203                        chip->ops->write_bit(chip, (data & 1));
 204                        data >>= 1;
 205                        udelay(1);
 206                }
 207        }
 208}
 209
 210static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
 211{
 212        unsigned int data = 0;
 213        int i;
 214
 215        for (i = 0; i < 4; i++) {
 216                chip->ops->write_bit(chip, (address & 1));
 217                address >>= 1;
 218                udelay(1);
 219        }
 220
 221        for (i = 0; i < 8; i++) {
 222                data >>= 1;
 223                if (chip->ops->read_bit(chip))
 224                        data |= 0x80;
 225                udelay(1);
 226        }
 227
 228        return data;
 229}
 230
 231static int v3020_read_time(struct device *dev, struct rtc_time *dt)
 232{
 233        struct v3020 *chip = dev_get_drvdata(dev);
 234        int tmp;
 235
 236        /* Copy the current time to ram... */
 237        v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);
 238
 239        /* ...and then read constant values. */
 240        tmp = v3020_get_reg(chip, V3020_SECONDS);
 241        dt->tm_sec      = bcd2bin(tmp);
 242        tmp = v3020_get_reg(chip, V3020_MINUTES);
 243        dt->tm_min      = bcd2bin(tmp);
 244        tmp = v3020_get_reg(chip, V3020_HOURS);
 245        dt->tm_hour     = bcd2bin(tmp);
 246        tmp = v3020_get_reg(chip, V3020_MONTH_DAY);
 247        dt->tm_mday     = bcd2bin(tmp);
 248        tmp = v3020_get_reg(chip, V3020_MONTH);
 249        dt->tm_mon    = bcd2bin(tmp) - 1;
 250        tmp = v3020_get_reg(chip, V3020_WEEK_DAY);
 251        dt->tm_wday     = bcd2bin(tmp);
 252        tmp = v3020_get_reg(chip, V3020_YEAR);
 253        dt->tm_year = bcd2bin(tmp)+100;
 254
 255        dev_dbg(dev, "\n%s : Read RTC values\n", __func__);
 256        dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
 257        dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
 258        dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
 259        dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
 260        dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
 261        dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
 262        dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
 263
 264        return 0;
 265}
 266
 267
 268static int v3020_set_time(struct device *dev, struct rtc_time *dt)
 269{
 270        struct v3020 *chip = dev_get_drvdata(dev);
 271
 272        dev_dbg(dev, "\n%s : Setting RTC values\n", __func__);
 273        dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
 274        dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
 275        dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
 276        dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
 277        dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
 278        dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
 279
 280        /* Write all the values to ram... */
 281        v3020_set_reg(chip, V3020_SECONDS,      bin2bcd(dt->tm_sec));
 282        v3020_set_reg(chip, V3020_MINUTES,      bin2bcd(dt->tm_min));
 283        v3020_set_reg(chip, V3020_HOURS,        bin2bcd(dt->tm_hour));
 284        v3020_set_reg(chip, V3020_MONTH_DAY,    bin2bcd(dt->tm_mday));
 285        v3020_set_reg(chip, V3020_MONTH,     bin2bcd(dt->tm_mon + 1));
 286        v3020_set_reg(chip, V3020_WEEK_DAY,     bin2bcd(dt->tm_wday));
 287        v3020_set_reg(chip, V3020_YEAR,         bin2bcd(dt->tm_year % 100));
 288
 289        /* ...and set the clock. */
 290        v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);
 291
 292        /* Compulab used this delay here. I dont know why,
 293         * the datasheet does not specify a delay. */
 294        /*mdelay(5);*/
 295
 296        return 0;
 297}
 298
 299static const struct rtc_class_ops v3020_rtc_ops = {
 300        .read_time      = v3020_read_time,
 301        .set_time       = v3020_set_time,
 302};
 303
 304static int rtc_probe(struct platform_device *pdev)
 305{
 306        struct v3020_platform_data *pdata = pdev->dev.platform_data;
 307        struct v3020 *chip;
 308        int retval = -EBUSY;
 309        int i;
 310        int temp;
 311
 312        chip = kzalloc(sizeof *chip, GFP_KERNEL);
 313        if (!chip)
 314                return -ENOMEM;
 315
 316        if (pdata->use_gpio)
 317                chip->ops = &v3020_gpio_ops;
 318        else
 319                chip->ops = &v3020_mmio_ops;
 320
 321        retval = chip->ops->map_io(chip, pdev, pdata);
 322        if (retval)
 323                goto err_chip;
 324
 325        /* Make sure the v3020 expects a communication cycle
 326         * by reading 8 times */
 327        for (i = 0; i < 8; i++)
 328                temp = chip->ops->read_bit(chip);
 329
 330        /* Test chip by doing a write/read sequence
 331         * to the chip ram */
 332        v3020_set_reg(chip, V3020_SECONDS, 0x33);
 333        if (v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
 334                retval = -ENODEV;
 335                goto err_io;
 336        }
 337
 338        /* Make sure frequency measurement mode, test modes, and lock
 339         * are all disabled */
 340        v3020_set_reg(chip, V3020_STATUS_0, 0x0);
 341
 342        if (pdata->use_gpio)
 343                dev_info(&pdev->dev, "Chip available at GPIOs "
 344                         "%d, %d, %d, %d\n",
 345                         chip->gpio[V3020_CS].gpio, chip->gpio[V3020_WR].gpio,
 346                         chip->gpio[V3020_RD].gpio, chip->gpio[V3020_IO].gpio);
 347        else
 348                dev_info(&pdev->dev, "Chip available at "
 349                         "physical address 0x%llx,"
 350                         "data connected to D%d\n",
 351                         (unsigned long long)pdev->resource[0].start,
 352                         chip->leftshift);
 353
 354        platform_set_drvdata(pdev, chip);
 355
 356        chip->rtc = rtc_device_register("v3020",
 357                                &pdev->dev, &v3020_rtc_ops, THIS_MODULE);
 358        if (IS_ERR(chip->rtc)) {
 359                retval = PTR_ERR(chip->rtc);
 360                goto err_io;
 361        }
 362
 363        return 0;
 364
 365err_io:
 366        chip->ops->unmap_io(chip);
 367err_chip:
 368        kfree(chip);
 369
 370        return retval;
 371}
 372
 373static int rtc_remove(struct platform_device *dev)
 374{
 375        struct v3020 *chip = platform_get_drvdata(dev);
 376        struct rtc_device *rtc = chip->rtc;
 377
 378        if (rtc)
 379                rtc_device_unregister(rtc);
 380
 381        chip->ops->unmap_io(chip);
 382        kfree(chip);
 383
 384        return 0;
 385}
 386
 387static struct platform_driver rtc_device_driver = {
 388        .probe  = rtc_probe,
 389        .remove = rtc_remove,
 390        .driver = {
 391                .name   = "v3020",
 392                .owner  = THIS_MODULE,
 393        },
 394};
 395
 396module_platform_driver(rtc_device_driver);
 397
 398MODULE_DESCRIPTION("V3020 RTC");
 399MODULE_AUTHOR("Raphael Assenat");
 400MODULE_LICENSE("GPL");
 401MODULE_ALIAS("platform:v3020");
 402
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