linux/drivers/rtc/rtc-rp5c01.c
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   1/*
   2 *  Ricoh RP5C01 RTC Driver
   3 *
   4 *  Copyright 2009 Geert Uytterhoeven
   5 *
   6 *  Based on the A3000 TOD code in arch/m68k/amiga/config.c
   7 *  Copyright (C) 1993 Hamish Macdonald
   8 */
   9
  10#include <linux/io.h>
  11#include <linux/kernel.h>
  12#include <linux/module.h>
  13#include <linux/platform_device.h>
  14#include <linux/rtc.h>
  15#include <linux/slab.h>
  16
  17
  18enum {
  19        RP5C01_1_SECOND         = 0x0,  /* MODE 00 */
  20        RP5C01_10_SECOND        = 0x1,  /* MODE 00 */
  21        RP5C01_1_MINUTE         = 0x2,  /* MODE 00 and MODE 01 */
  22        RP5C01_10_MINUTE        = 0x3,  /* MODE 00 and MODE 01 */
  23        RP5C01_1_HOUR           = 0x4,  /* MODE 00 and MODE 01 */
  24        RP5C01_10_HOUR          = 0x5,  /* MODE 00 and MODE 01 */
  25        RP5C01_DAY_OF_WEEK      = 0x6,  /* MODE 00 and MODE 01 */
  26        RP5C01_1_DAY            = 0x7,  /* MODE 00 and MODE 01 */
  27        RP5C01_10_DAY           = 0x8,  /* MODE 00 and MODE 01 */
  28        RP5C01_1_MONTH          = 0x9,  /* MODE 00 */
  29        RP5C01_10_MONTH         = 0xa,  /* MODE 00 */
  30        RP5C01_1_YEAR           = 0xb,  /* MODE 00 */
  31        RP5C01_10_YEAR          = 0xc,  /* MODE 00 */
  32
  33        RP5C01_12_24_SELECT     = 0xa,  /* MODE 01 */
  34        RP5C01_LEAP_YEAR        = 0xb,  /* MODE 01 */
  35
  36        RP5C01_MODE             = 0xd,  /* all modes */
  37        RP5C01_TEST             = 0xe,  /* all modes */
  38        RP5C01_RESET            = 0xf,  /* all modes */
  39};
  40
  41#define RP5C01_12_24_SELECT_12  (0 << 0)
  42#define RP5C01_12_24_SELECT_24  (1 << 0)
  43
  44#define RP5C01_10_HOUR_AM       (0 << 1)
  45#define RP5C01_10_HOUR_PM       (1 << 1)
  46
  47#define RP5C01_MODE_TIMER_EN    (1 << 3)        /* timer enable */
  48#define RP5C01_MODE_ALARM_EN    (1 << 2)        /* alarm enable */
  49
  50#define RP5C01_MODE_MODE_MASK   (3 << 0)
  51#define RP5C01_MODE_MODE00      (0 << 0)        /* time */
  52#define RP5C01_MODE_MODE01      (1 << 0)        /* alarm, 12h/24h, leap year */
  53#define RP5C01_MODE_RAM_BLOCK10 (2 << 0)        /* RAM 4 bits x 13 */
  54#define RP5C01_MODE_RAM_BLOCK11 (3 << 0)        /* RAM 4 bits x 13 */
  55
  56#define RP5C01_RESET_1HZ_PULSE  (1 << 3)
  57#define RP5C01_RESET_16HZ_PULSE (1 << 2)
  58#define RP5C01_RESET_SECOND     (1 << 1)        /* reset divider stages for */
  59                                                /* seconds or smaller units */
  60#define RP5C01_RESET_ALARM      (1 << 0)        /* reset all alarm registers */
  61
  62
  63struct rp5c01_priv {
  64        u32 __iomem *regs;
  65        struct rtc_device *rtc;
  66        spinlock_t lock;        /* against concurrent RTC/NVRAM access */
  67        struct bin_attribute nvram_attr;
  68};
  69
  70static inline unsigned int rp5c01_read(struct rp5c01_priv *priv,
  71                                       unsigned int reg)
  72{
  73        return __raw_readl(&priv->regs[reg]) & 0xf;
  74}
  75
  76static inline void rp5c01_write(struct rp5c01_priv *priv, unsigned int val,
  77                                unsigned int reg)
  78{
  79        __raw_writel(val, &priv->regs[reg]);
  80}
  81
  82static void rp5c01_lock(struct rp5c01_priv *priv)
  83{
  84        rp5c01_write(priv, RP5C01_MODE_MODE00, RP5C01_MODE);
  85}
  86
  87static void rp5c01_unlock(struct rp5c01_priv *priv)
  88{
  89        rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
  90                     RP5C01_MODE);
  91}
  92
  93static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
  94{
  95        struct rp5c01_priv *priv = dev_get_drvdata(dev);
  96
  97        spin_lock_irq(&priv->lock);
  98        rp5c01_lock(priv);
  99
 100        tm->tm_sec  = rp5c01_read(priv, RP5C01_10_SECOND) * 10 +
 101                      rp5c01_read(priv, RP5C01_1_SECOND);
 102        tm->tm_min  = rp5c01_read(priv, RP5C01_10_MINUTE) * 10 +
 103                      rp5c01_read(priv, RP5C01_1_MINUTE);
 104        tm->tm_hour = rp5c01_read(priv, RP5C01_10_HOUR) * 10 +
 105                      rp5c01_read(priv, RP5C01_1_HOUR);
 106        tm->tm_mday = rp5c01_read(priv, RP5C01_10_DAY) * 10 +
 107                      rp5c01_read(priv, RP5C01_1_DAY);
 108        tm->tm_wday = rp5c01_read(priv, RP5C01_DAY_OF_WEEK);
 109        tm->tm_mon  = rp5c01_read(priv, RP5C01_10_MONTH) * 10 +
 110                      rp5c01_read(priv, RP5C01_1_MONTH) - 1;
 111        tm->tm_year = rp5c01_read(priv, RP5C01_10_YEAR) * 10 +
 112                      rp5c01_read(priv, RP5C01_1_YEAR);
 113        if (tm->tm_year <= 69)
 114                tm->tm_year += 100;
 115
 116        rp5c01_unlock(priv);
 117        spin_unlock_irq(&priv->lock);
 118
 119        return rtc_valid_tm(tm);
 120}
 121
 122static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
 123{
 124        struct rp5c01_priv *priv = dev_get_drvdata(dev);
 125
 126        spin_lock_irq(&priv->lock);
 127        rp5c01_lock(priv);
 128
 129        rp5c01_write(priv, tm->tm_sec / 10, RP5C01_10_SECOND);
 130        rp5c01_write(priv, tm->tm_sec % 10, RP5C01_1_SECOND);
 131        rp5c01_write(priv, tm->tm_min / 10, RP5C01_10_MINUTE);
 132        rp5c01_write(priv, tm->tm_min % 10, RP5C01_1_MINUTE);
 133        rp5c01_write(priv, tm->tm_hour / 10, RP5C01_10_HOUR);
 134        rp5c01_write(priv, tm->tm_hour % 10, RP5C01_1_HOUR);
 135        rp5c01_write(priv, tm->tm_mday / 10, RP5C01_10_DAY);
 136        rp5c01_write(priv, tm->tm_mday % 10, RP5C01_1_DAY);
 137        if (tm->tm_wday != -1)
 138                rp5c01_write(priv, tm->tm_wday, RP5C01_DAY_OF_WEEK);
 139        rp5c01_write(priv, (tm->tm_mon + 1) / 10, RP5C01_10_MONTH);
 140        rp5c01_write(priv, (tm->tm_mon + 1) % 10, RP5C01_1_MONTH);
 141        if (tm->tm_year >= 100)
 142                tm->tm_year -= 100;
 143        rp5c01_write(priv, tm->tm_year / 10, RP5C01_10_YEAR);
 144        rp5c01_write(priv, tm->tm_year % 10, RP5C01_1_YEAR);
 145
 146        rp5c01_unlock(priv);
 147        spin_unlock_irq(&priv->lock);
 148        return 0;
 149}
 150
 151static const struct rtc_class_ops rp5c01_rtc_ops = {
 152        .read_time      = rp5c01_read_time,
 153        .set_time       = rp5c01_set_time,
 154};
 155
 156
 157/*
 158 * The NVRAM is organized as 2 blocks of 13 nibbles of 4 bits.
 159 * We provide access to them like AmigaOS does: the high nibble of each 8-bit
 160 * byte is stored in BLOCK10, the low nibble in BLOCK11.
 161 */
 162
 163static ssize_t rp5c01_nvram_read(struct file *filp, struct kobject *kobj,
 164                                 struct bin_attribute *bin_attr,
 165                                 char *buf, loff_t pos, size_t size)
 166{
 167        struct device *dev = container_of(kobj, struct device, kobj);
 168        struct rp5c01_priv *priv = dev_get_drvdata(dev);
 169        ssize_t count;
 170
 171        spin_lock_irq(&priv->lock);
 172
 173        for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
 174                u8 data;
 175
 176                rp5c01_write(priv,
 177                             RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
 178                             RP5C01_MODE);
 179                data = rp5c01_read(priv, pos) << 4;
 180                rp5c01_write(priv,
 181                             RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
 182                             RP5C01_MODE);
 183                data |= rp5c01_read(priv, pos++);
 184                rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
 185                             RP5C01_MODE);
 186                *buf++ = data;
 187        }
 188
 189        spin_unlock_irq(&priv->lock);
 190        return count;
 191}
 192
 193static ssize_t rp5c01_nvram_write(struct file *filp, struct kobject *kobj,
 194                                  struct bin_attribute *bin_attr,
 195                                  char *buf, loff_t pos, size_t size)
 196{
 197        struct device *dev = container_of(kobj, struct device, kobj);
 198        struct rp5c01_priv *priv = dev_get_drvdata(dev);
 199        ssize_t count;
 200
 201        spin_lock_irq(&priv->lock);
 202
 203        for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
 204                u8 data = *buf++;
 205
 206                rp5c01_write(priv,
 207                             RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
 208                             RP5C01_MODE);
 209                rp5c01_write(priv, data >> 4, pos);
 210                rp5c01_write(priv,
 211                             RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
 212                             RP5C01_MODE);
 213                rp5c01_write(priv, data & 0xf, pos++);
 214                rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
 215                             RP5C01_MODE);
 216        }
 217
 218        spin_unlock_irq(&priv->lock);
 219        return count;
 220}
 221
 222static int __init rp5c01_rtc_probe(struct platform_device *dev)
 223{
 224        struct resource *res;
 225        struct rp5c01_priv *priv;
 226        struct rtc_device *rtc;
 227        int error;
 228
 229        res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 230        if (!res)
 231                return -ENODEV;
 232
 233        priv = devm_kzalloc(&dev->dev, sizeof(*priv), GFP_KERNEL);
 234        if (!priv)
 235                return -ENOMEM;
 236
 237        priv->regs = devm_ioremap(&dev->dev, res->start, resource_size(res));
 238        if (!priv->regs)
 239                return -ENOMEM;
 240
 241        sysfs_bin_attr_init(&priv->nvram_attr);
 242        priv->nvram_attr.attr.name = "nvram";
 243        priv->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
 244        priv->nvram_attr.read = rp5c01_nvram_read;
 245        priv->nvram_attr.write = rp5c01_nvram_write;
 246        priv->nvram_attr.size = RP5C01_MODE;
 247
 248        spin_lock_init(&priv->lock);
 249
 250        platform_set_drvdata(dev, priv);
 251
 252        rtc = devm_rtc_device_register(&dev->dev, "rtc-rp5c01", &rp5c01_rtc_ops,
 253                                  THIS_MODULE);
 254        if (IS_ERR(rtc)) {
 255                error = PTR_ERR(rtc);
 256                goto out;
 257        }
 258        priv->rtc = rtc;
 259
 260        error = sysfs_create_bin_file(&dev->dev.kobj, &priv->nvram_attr);
 261        if (error)
 262                goto out;
 263
 264        return 0;
 265
 266out:
 267        platform_set_drvdata(dev, NULL);
 268        return error;
 269}
 270
 271static int __exit rp5c01_rtc_remove(struct platform_device *dev)
 272{
 273        struct rp5c01_priv *priv = platform_get_drvdata(dev);
 274
 275        sysfs_remove_bin_file(&dev->dev.kobj, &priv->nvram_attr);
 276        return 0;
 277}
 278
 279static struct platform_driver rp5c01_rtc_driver = {
 280        .driver = {
 281                .name   = "rtc-rp5c01",
 282                .owner  = THIS_MODULE,
 283        },
 284        .remove = __exit_p(rp5c01_rtc_remove),
 285};
 286
 287module_platform_driver_probe(rp5c01_rtc_driver, rp5c01_rtc_probe);
 288
 289MODULE_AUTHOR("Geert Uytterhoeven <geert@linux-m68k.org>");
 290MODULE_LICENSE("GPL");
 291MODULE_DESCRIPTION("Ricoh RP5C01 RTC driver");
 292MODULE_ALIAS("platform:rtc-rp5c01");
 293
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