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/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
  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 {
  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
  66 static 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
  83 static void v3020_mmio_unmap(struct v3020 *chip)
  84 {
  85         iounmap(chip->ioaddress);
  86 }
  87
  88 static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
  89 {
  90         writel(bit << chip->leftshift, chip->ioaddress);
  91 }
  92
  93 static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
  94 {
  95         return !!(readl(chip->ioaddress) & (1 << chip->leftshift));
  96 }
  97
  98 static 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
 105 static 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
 112 static 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
 130 static void v3020_gpio_unmap(struct v3020 *chip)
 131 {
 132         gpio_free_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
 133 }
 134
 135 static 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
 145 static 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
 161 static 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
 168 static 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
 191 static 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
 212 static 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
 249 static 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
 280 static const struct rtc_class_ops v3020_rtc_ops = {
 281         .read_time      = v3020_read_time,
 282         .set_time       = v3020_set_time,
 283 };
 284
 285 static 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
 346 err_io:
 347         chip->ops->unmap_io(chip);
 348
 349         return retval;
 350 }
 351
 352 static 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
 361 static struct platform_driver rtc_device_driver = {
 362         .probe  = rtc_probe,
 363         .remove = rtc_remove,
 364         .driver = {
 365                 .name   = "v3020",
 366         },
 367 };
 368
 369 module_platform_driver(rtc_device_driver);
 370
 371 MODULE_DESCRIPTION("V3020 RTC");
 372 MODULE_AUTHOR("Raphael Assenat");
 373 MODULE_LICENSE("GPL");
 374 MODULE_ALIAS("platform:v3020");