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 #include <linux/gpio.h>
  31
  32 #include <linux/io.h>
  33
  34 #undef DEBUG
  35
  36 struct v3020;
  37
  38 struct v3020_chip_ops {
  39         int (*map_io)(struct v3020 *chip, struct platform_device *pdev,
  40                       struct v3020_platform_data *pdata);
  41         void (*unmap_io)(struct v3020 *chip);
  42         unsigned char (*read_bit)(struct v3020 *chip);
  43         void (*write_bit)(struct v3020 *chip, unsigned char bit);
  44 };
  45
  46 #define V3020_CS        0
  47 #define V3020_WR        1
  48 #define V3020_RD        2
  49 #define V3020_IO        3
  50
  51 struct v3020_gpio {
  52         const char *name;
  53         unsigned int gpio;
  54 };
  55
  56 struct v3020 {
  57         /* MMIO access */
  58         void __iomem *ioaddress;
  59         int leftshift;
  60
  61         /* GPIO access */
  62         struct v3020_gpio *gpio;
  63
  64         struct v3020_chip_ops *ops;
  65
  66         struct rtc_device *rtc;
  67 };
  68
  69
  70 static int v3020_mmio_map(struct v3020 *chip, struct platform_device *pdev,
  71                           struct v3020_platform_data *pdata)
  72 {
  73         if (pdev->num_resources != 1)
  74                 return -EBUSY;
  75
  76         if (pdev->resource[0].flags != IORESOURCE_MEM)
  77                 return -EBUSY;
  78
  79         chip->leftshift = pdata->leftshift;
  80         chip->ioaddress = ioremap(pdev->resource[0].start, 1);
  81         if (chip->ioaddress == NULL)
  82                 return -EBUSY;
  83
  84         return 0;
  85 }
  86
  87 static void v3020_mmio_unmap(struct v3020 *chip)
  88 {
  89         iounmap(chip->ioaddress);
  90 }
  91
  92 static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
  93 {
  94         writel(bit << chip->leftshift, chip->ioaddress);
  95 }
  96
  97 static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
  98 {
  99         return !!(readl(chip->ioaddress) & (1 << chip->leftshift));
 100 }
 101
 102 static struct v3020_chip_ops v3020_mmio_ops = {
 103         .map_io         = v3020_mmio_map,
 104         .unmap_io       = v3020_mmio_unmap,
 105         .read_bit       = v3020_mmio_read_bit,
 106         .write_bit      = v3020_mmio_write_bit,
 107 };
 108
 109 static struct v3020_gpio v3020_gpio[] = {
 110         { "RTC CS", 0 },
 111         { "RTC WR", 0 },
 112         { "RTC RD", 0 },
 113         { "RTC IO", 0 },
 114 };
 115
 116 static int v3020_gpio_map(struct v3020 *chip, struct platform_device *pdev,
 117                           struct v3020_platform_data *pdata)
 118 {
 119         int i, err;
 120
 121         v3020_gpio[V3020_CS].gpio = pdata->gpio_cs;
 122         v3020_gpio[V3020_WR].gpio = pdata->gpio_wr;
 123         v3020_gpio[V3020_RD].gpio = pdata->gpio_rd;
 124         v3020_gpio[V3020_IO].gpio = pdata->gpio_io;
 125
 126         for (i = 0; i < ARRAY_SIZE(v3020_gpio); i++) {
 127                 err = gpio_request(v3020_gpio[i].gpio, v3020_gpio[i].name);
 128                 if (err)
 129                         goto err_request;
 130
 131                 gpio_direction_output(v3020_gpio[i].gpio, 1);
 132         }
 133
 134         chip->gpio = v3020_gpio;
 135
 136         return 0;
 137
 138 err_request:
 139         while (--i >= 0)
 140                 gpio_free(v3020_gpio[i].gpio);
 141
 142         return err;
 143 }
 144
 145 static void v3020_gpio_unmap(struct v3020 *chip)
 146 {
 147         int i;
 148
 149         for (i = 0; i < ARRAY_SIZE(v3020_gpio); i++)
 150                 gpio_free(v3020_gpio[i].gpio);
 151 }
 152
 153 static void v3020_gpio_write_bit(struct v3020 *chip, unsigned char bit)
 154 {
 155         gpio_direction_output(chip->gpio[V3020_IO].gpio, bit);
 156         gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
 157         gpio_set_value(chip->gpio[V3020_WR].gpio, 0);
 158         udelay(1);
 159         gpio_set_value(chip->gpio[V3020_WR].gpio, 1);
 160         gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
 161 }
 162
 163 static unsigned char v3020_gpio_read_bit(struct v3020 *chip)
 164 {
 165         int bit;
 166
 167         gpio_direction_input(chip->gpio[V3020_IO].gpio);
 168         gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
 169         gpio_set_value(chip->gpio[V3020_RD].gpio, 0);
 170         udelay(1);
 171         bit = !!gpio_get_value(chip->gpio[V3020_IO].gpio);
 172         udelay(1);
 173         gpio_set_value(chip->gpio[V3020_RD].gpio, 1);
 174         gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
 175
 176         return bit;
 177 }
 178
 179 static struct v3020_chip_ops v3020_gpio_ops = {
 180         .map_io         = v3020_gpio_map,
 181         .unmap_io       = v3020_gpio_unmap,
 182         .read_bit       = v3020_gpio_read_bit,
 183         .write_bit      = v3020_gpio_write_bit,
 184 };
 185
 186 static void v3020_set_reg(struct v3020 *chip, unsigned char address,
 187                         unsigned char data)
 188 {
 189         int i;
 190         unsigned char tmp;
 191
 192         tmp = address;
 193         for (i = 0; i < 4; i++) {
 194                 chip->ops->write_bit(chip, (tmp & 1));
 195                 tmp >>= 1;
 196                 udelay(1);
 197         }
 198
 199         /* Commands dont have data */
 200         if (!V3020_IS_COMMAND(address)) {
 201                 for (i = 0; i < 8; i++) {
 202                         chip->ops->write_bit(chip, (data & 1));
 203                         data >>= 1;
 204                         udelay(1);
 205                 }
 206         }
 207 }
 208
 209 static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
 210 {
 211         unsigned int data = 0;
 212         int i;
 213
 214         for (i = 0; i < 4; i++) {
 215                 chip->ops->write_bit(chip, (address & 1));
 216                 address >>= 1;
 217                 udelay(1);
 218         }
 219
 220         for (i = 0; i < 8; i++) {
 221                 data >>= 1;
 222                 if (chip->ops->read_bit(chip))
 223                         data |= 0x80;
 224                 udelay(1);
 225         }
 226
 227         return data;
 228 }
 229
 230 static int v3020_read_time(struct device *dev, struct rtc_time *dt)
 231 {
 232         struct v3020 *chip = dev_get_drvdata(dev);
 233         int tmp;
 234
 235         /* Copy the current time to ram... */
 236         v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);
 237
 238         /* ...and then read constant values. */
 239         tmp = v3020_get_reg(chip, V3020_SECONDS);
 240         dt->tm_sec      = bcd2bin(tmp);
 241         tmp = v3020_get_reg(chip, V3020_MINUTES);
 242         dt->tm_min      = bcd2bin(tmp);
 243         tmp = v3020_get_reg(chip, V3020_HOURS);
 244         dt->tm_hour     = bcd2bin(tmp);
 245         tmp = v3020_get_reg(chip, V3020_MONTH_DAY);
 246         dt->tm_mday     = bcd2bin(tmp);
 247         tmp = v3020_get_reg(chip, V3020_MONTH);
 248         dt->tm_mon    = bcd2bin(tmp) - 1;
 249         tmp = v3020_get_reg(chip, V3020_WEEK_DAY);
 250         dt->tm_wday     = bcd2bin(tmp);
 251         tmp = v3020_get_reg(chip, V3020_YEAR);
 252         dt->tm_year = bcd2bin(tmp)+100;
 253
 254         dev_dbg(dev, "\n%s : Read RTC values\n", __func__);
 255         dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
 256         dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
 257         dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
 258         dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
 259         dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
 260         dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
 261         dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
 262
 263         return 0;
 264 }
 265
 266
 267 static int v3020_set_time(struct device *dev, struct rtc_time *dt)
 268 {
 269         struct v3020 *chip = dev_get_drvdata(dev);
 270
 271         dev_dbg(dev, "\n%s : Setting RTC values\n", __func__);
 272         dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
 273         dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
 274         dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
 275         dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
 276         dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
 277         dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
 278
 279         /* Write all the values to ram... */
 280         v3020_set_reg(chip, V3020_SECONDS,      bin2bcd(dt->tm_sec));
 281         v3020_set_reg(chip, V3020_MINUTES,      bin2bcd(dt->tm_min));
 282         v3020_set_reg(chip, V3020_HOURS,        bin2bcd(dt->tm_hour));
 283         v3020_set_reg(chip, V3020_MONTH_DAY,    bin2bcd(dt->tm_mday));
 284         v3020_set_reg(chip, V3020_MONTH,     bin2bcd(dt->tm_mon + 1));
 285         v3020_set_reg(chip, V3020_WEEK_DAY,     bin2bcd(dt->tm_wday));
 286         v3020_set_reg(chip, V3020_YEAR,         bin2bcd(dt->tm_year % 100));
 287
 288         /* ...and set the clock. */
 289         v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);
 290
 291         /* Compulab used this delay here. I dont know why,
 292          * the datasheet does not specify a delay. */
 293         /*mdelay(5);*/
 294
 295         return 0;
 296 }
 297
 298 static const struct rtc_class_ops v3020_rtc_ops = {
 299         .read_time      = v3020_read_time,
 300         .set_time       = v3020_set_time,
 301 };
 302
 303 static int rtc_probe(struct platform_device *pdev)
 304 {
 305         struct v3020_platform_data *pdata = pdev->dev.platform_data;
 306         struct v3020 *chip;
 307         int retval = -EBUSY;
 308         int i;
 309         int temp;
 310
 311         chip = kzalloc(sizeof *chip, GFP_KERNEL);
 312         if (!chip)
 313                 return -ENOMEM;
 314
 315         if (pdata->use_gpio)
 316                 chip->ops = &v3020_gpio_ops;
 317         else
 318                 chip->ops = &v3020_mmio_ops;
 319
 320         retval = chip->ops->map_io(chip, pdev, pdata);
 321         if (retval)
 322                 goto err_chip;
 323
 324         /* Make sure the v3020 expects a communication cycle
 325          * by reading 8 times */
 326         for (i = 0; i < 8; i++)
 327                 temp = chip->ops->read_bit(chip);
 328
 329         /* Test chip by doing a write/read sequence
 330          * to the chip ram */
 331         v3020_set_reg(chip, V3020_SECONDS, 0x33);
 332         if (v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
 333                 retval = -ENODEV;
 334                 goto err_io;
 335         }
 336
 337         /* Make sure frequency measurement mode, test modes, and lock
 338          * are all disabled */
 339         v3020_set_reg(chip, V3020_STATUS_0, 0x0);
 340
 341         if (pdata->use_gpio)
 342                 dev_info(&pdev->dev, "Chip available at GPIOs "
 343                          "%d, %d, %d, %d\n",
 344                          chip->gpio[V3020_CS].gpio, chip->gpio[V3020_WR].gpio,
 345                          chip->gpio[V3020_RD].gpio, chip->gpio[V3020_IO].gpio);
 346         else
 347                 dev_info(&pdev->dev, "Chip available at "
 348                          "physical address 0x%llx,"
 349                          "data connected to D%d\n",
 350                          (unsigned long long)pdev->resource[0].start,
 351                          chip->leftshift);
 352
 353         platform_set_drvdata(pdev, chip);
 354
 355         chip->rtc = rtc_device_register("v3020",
 356                                 &pdev->dev, &v3020_rtc_ops, THIS_MODULE);
 357         if (IS_ERR(chip->rtc)) {
 358                 retval = PTR_ERR(chip->rtc);
 359                 goto err_io;
 360         }
 361
 362         return 0;
 363
 364 err_io:
 365         chip->ops->unmap_io(chip);
 366 err_chip:
 367         kfree(chip);
 368
 369         return retval;
 370 }
 371
 372 static int rtc_remove(struct platform_device *dev)
 373 {
 374         struct v3020 *chip = platform_get_drvdata(dev);
 375         struct rtc_device *rtc = chip->rtc;
 376
 377         if (rtc)
 378                 rtc_device_unregister(rtc);
 379
 380         chip->ops->unmap_io(chip);
 381         kfree(chip);
 382
 383         return 0;
 384 }
 385
 386 static struct platform_driver rtc_device_driver = {
 387         .probe  = rtc_probe,
 388         .remove = rtc_remove,
 389         .driver = {
 390                 .name   = "v3020",
 391                 .owner  = THIS_MODULE,
 392         },
 393 };
 394
 395 static __init int v3020_init(void)
 396 {
 397         return platform_driver_register(&rtc_device_driver);
 398 }
 399
 400 static __exit void v3020_exit(void)
 401 {
 402         platform_driver_unregister(&rtc_device_driver);
 403 }
 404
 405 module_init(v3020_init);
 406 module_exit(v3020_exit);
 407
 408 MODULE_DESCRIPTION("V3020 RTC");
 409 MODULE_AUTHOR("Raphael Assenat");
 410 MODULE_LICENSE("GPL");
 411 MODULE_ALIAS("platform:v3020");