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 #include <linux/slab.h>
  32
  33 #include <linux/io.h>
  34
  35 #undef DEBUG
  36
  37 struct v3020;
  38
  39 struct 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
  52 struct v3020_gpio {
  53         const char *name;
  54         unsigned int gpio;
  55 };
  56
  57 struct 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
  71 static 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
  88 static void v3020_mmio_unmap(struct v3020 *chip)
  89 {
  90         iounmap(chip->ioaddress);
  91 }
  92
  93 static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
  94 {
  95         writel(bit << chip->leftshift, chip->ioaddress);
  96 }
  97
  98 static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
  99 {
 100         return !!(readl(chip->ioaddress) & (1 << chip->leftshift));
 101 }
 102
 103 static 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
 110 static struct v3020_gpio v3020_gpio[] = {
 111         { "RTC CS", 0 },
 112         { "RTC WR", 0 },
 113         { "RTC RD", 0 },
 114         { "RTC IO", 0 },
 115 };
 116
 117 static 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
 139 err_request:
 140         while (--i >= 0)
 141                 gpio_free(v3020_gpio[i].gpio);
 142
 143         return err;
 144 }
 145
 146 static 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
 154 static 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
 164 static 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
 180 static 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
 187 static 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
 210 static 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
 231 static 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
 268 static 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
 299 static const struct rtc_class_ops v3020_rtc_ops = {
 300         .read_time      = v3020_read_time,
 301         .set_time       = v3020_set_time,
 302 };
 303
 304 static 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 = devm_kzalloc(&pdev->dev, 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                 return retval;
 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 = devm_rtc_device_register(&pdev->dev, "v3020",
 357                                         &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
 365 err_io:
 366         chip->ops->unmap_io(chip);
 367
 368         return retval;
 369 }
 370
 371 static int rtc_remove(struct platform_device *dev)
 372 {
 373         struct v3020 *chip = platform_get_drvdata(dev);
 374
 375         chip->ops->unmap_io(chip);
 376
 377         return 0;
 378 }
 379
 380 static struct platform_driver rtc_device_driver = {
 381         .probe  = rtc_probe,
 382         .remove = rtc_remove,
 383         .driver = {
 384                 .name   = "v3020",
 385                 .owner  = THIS_MODULE,
 386         },
 387 };
 388
 389 module_platform_driver(rtc_device_driver);
 390
 391 MODULE_DESCRIPTION("V3020 RTC");
 392 MODULE_AUTHOR("Raphael Assenat");
 393 MODULE_LICENSE("GPL");
 394 MODULE_ALIAS("platform:v3020");