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   1 /*
   2  *  linux/drivers/acorn/char/pcf8583.c
   3  *
   4  *  Copyright (C) 2000 Russell King
   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 PCF8583 RTC & RAM chip
  11  */
  12 #include <linux/module.h>
  13 #include <linux/i2c.h>
  14 #include <linux/slab.h>
  15 #include <linux/string.h>
  16 #include <linux/mc146818rtc.h>
  17 #include <linux/init.h>
  18 #include <linux/errno.h>
  19 #include <linux/bcd.h>
  20
  21 #include "pcf8583.h"
  22
  23 static struct i2c_driver pcf8583_driver;
  24
  25 static unsigned short ignore[] = { I2C_CLIENT_END };
  26 static unsigned short normal_addr[] = { 0x50, I2C_CLIENT_END };
  27 static unsigned short *forces[] = { NULL };
  28
  29 static struct i2c_client_address_data addr_data = {
  30         .normal_i2c             = normal_addr,
  31         .probe                  = ignore,
  32         .ignore                 = ignore,
  33         .forces                 = forces,
  34 };
  35
  36 #define set_ctrl(x, v) i2c_set_clientdata(x, (void *)(unsigned int)(v))
  37 #define get_ctrl(x)    ((unsigned int)i2c_get_clientdata(x))
  38
  39 static int
  40 pcf8583_attach(struct i2c_adapter *adap, int addr, int kind)
  41 {
  42         struct i2c_client *c;
  43         unsigned char buf[1], ad[1] = { 0 };
  44         struct i2c_msg msgs[2] = {
  45                 {
  46                         .addr = addr,
  47                         .flags = 0,
  48                         .len = 1,
  49                         .buf = ad,
  50                 }, {
  51                         .addr = addr,
  52                         .flags = I2C_M_RD,
  53                         .len = 1,
  54                         .buf = buf,
  55                 }
  56         };
  57
  58         c = kmalloc(sizeof(*c), GFP_KERNEL);
  59         if (!c)
  60                 return -ENOMEM;
  61
  62         memset(c, 0, sizeof(*c));
  63         c->addr         = addr;
  64         c->adapter      = adap;
  65         c->driver       = &pcf8583_driver;
  66
  67         if (i2c_transfer(c->adapter, msgs, 2) == 2)
  68                 set_ctrl(c, buf[0]);
  69
  70         return i2c_attach_client(c);
  71 }
  72
  73 static int
  74 pcf8583_probe(struct i2c_adapter *adap)
  75 {
  76         return i2c_probe(adap, &addr_data, pcf8583_attach);
  77 }
  78
  79 static int
  80 pcf8583_detach(struct i2c_client *client)
  81 {
  82         i2c_detach_client(client);
  83         kfree(client);
  84         return 0;
  85 }
  86
  87 static int
  88 pcf8583_get_datetime(struct i2c_client *client, struct rtc_tm *dt)
  89 {
  90         unsigned char buf[8], addr[1] = { 1 };
  91         struct i2c_msg msgs[2] = {
  92                 {
  93                         .addr = client->addr,
  94                         .flags = 0,
  95                         .len = 1,
  96                         .buf = addr,
  97                 }, {
  98                         .addr = client->addr,
  99                         .flags = I2C_M_RD,
 100                         .len = 6,
 101                         .buf = buf,
 102                 }
 103         };
 104         int ret = -EIO;
 105
 106         memset(buf, 0, sizeof(buf));
 107
 108         ret = i2c_transfer(client->adapter, msgs, 2);
 109         if (ret == 2) {
 110                 dt->year_off = buf[4] >> 6;
 111                 dt->wday     = buf[5] >> 5;
 112
 113                 buf[4] &= 0x3f;
 114                 buf[5] &= 0x1f;
 115
 116                 dt->cs       = BCD_TO_BIN(buf[0]);
 117                 dt->secs     = BCD_TO_BIN(buf[1]);
 118                 dt->mins     = BCD_TO_BIN(buf[2]);
 119                 dt->hours    = BCD_TO_BIN(buf[3]);
 120                 dt->mday     = BCD_TO_BIN(buf[4]);
 121                 dt->mon      = BCD_TO_BIN(buf[5]);
 122
 123                 ret = 0;
 124         }
 125
 126         return ret;
 127 }
 128
 129 static int
 130 pcf8583_set_datetime(struct i2c_client *client, struct rtc_tm *dt, int datetoo)
 131 {
 132         unsigned char buf[8];
 133         int ret, len = 6;
 134
 135         buf[0] = 0;
 136         buf[1] = get_ctrl(client) | 0x80;
 137         buf[2] = BIN_TO_BCD(dt->cs);
 138         buf[3] = BIN_TO_BCD(dt->secs);
 139         buf[4] = BIN_TO_BCD(dt->mins);
 140         buf[5] = BIN_TO_BCD(dt->hours);
 141
 142         if (datetoo) {
 143                 len = 8;
 144                 buf[6] = BIN_TO_BCD(dt->mday) | (dt->year_off << 6);
 145                 buf[7] = BIN_TO_BCD(dt->mon)  | (dt->wday << 5);
 146         }
 147
 148         ret = i2c_master_send(client, (char *)buf, len);
 149         if (ret == len)
 150                 ret = 0;
 151
 152         buf[1] = get_ctrl(client);
 153         i2c_master_send(client, (char *)buf, 2);
 154
 155         return ret;
 156 }
 157
 158 static int
 159 pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)
 160 {
 161         *ctrl = get_ctrl(client);
 162         return 0;
 163 }
 164
 165 static int
 166 pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl)
 167 {
 168         unsigned char buf[2];
 169
 170         buf[0] = 0;
 171         buf[1] = *ctrl;
 172         set_ctrl(client, *ctrl);
 173
 174         return i2c_master_send(client, (char *)buf, 2);
 175 }
 176
 177 static int
 178 pcf8583_read_mem(struct i2c_client *client, struct mem *mem)
 179 {
 180         unsigned char addr[1];
 181         struct i2c_msg msgs[2] = {
 182                 {
 183                         .addr = client->addr,
 184                         .flags = 0,
 185                         .len = 1,
 186                         .buf = addr,
 187                 }, {
 188                         .addr = client->addr,
 189                         .flags = I2C_M_RD,
 190                         .len = mem->nr,
 191                         .buf = mem->data,
 192                 }
 193         };
 194
 195         if (mem->loc < 8)
 196                 return -EINVAL;
 197
 198         addr[0] = mem->loc;
 199
 200         return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
 201 }
 202
 203 static int
 204 pcf8583_write_mem(struct i2c_client *client, struct mem *mem)
 205 {
 206         unsigned char addr[1];
 207         struct i2c_msg msgs[2] = {
 208                 {
 209                         .addr = client->addr,
 210                         .flags = 0,
 211                         .len = 1,
 212                         .buf = addr,
 213                 }, {
 214                         .addr = client->addr,
 215                         .flags = I2C_M_NOSTART,
 216                         .len = mem->nr,
 217                         .buf = mem->data,
 218                 }
 219         };
 220
 221         if (mem->loc < 8)
 222                 return -EINVAL;
 223
 224         addr[0] = mem->loc;
 225
 226         return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
 227 }
 228
 229 static int
 230 pcf8583_command(struct i2c_client *client, unsigned int cmd, void *arg)
 231 {
 232         switch (cmd) {
 233         case RTC_GETDATETIME:
 234                 return pcf8583_get_datetime(client, arg);
 235
 236         case RTC_SETTIME:
 237                 return pcf8583_set_datetime(client, arg, 0);
 238
 239         case RTC_SETDATETIME:
 240                 return pcf8583_set_datetime(client, arg, 1);
 241
 242         case RTC_GETCTRL:
 243                 return pcf8583_get_ctrl(client, arg);
 244
 245         case RTC_SETCTRL:
 246                 return pcf8583_set_ctrl(client, arg);
 247
 248         case MEM_READ:
 249                 return pcf8583_read_mem(client, arg);
 250
 251         case MEM_WRITE:
 252                 return pcf8583_write_mem(client, arg);
 253
 254         default:
 255                 return -EINVAL;
 256         }
 257 }
 258
 259 static struct i2c_driver pcf8583_driver = {
 260         .driver = {
 261                 .name   = "PCF8583",
 262         },
 263         .id             = I2C_DRIVERID_PCF8583,
 264         .attach_adapter = pcf8583_probe,
 265         .detach_client  = pcf8583_detach,
 266         .command        = pcf8583_command
 267 };
 268
 269 static __init int pcf8583_init(void)
 270 {
 271         return i2c_add_driver(&pcf8583_driver);
 272 }
 273
 274 static __exit void pcf8583_exit(void)
 275 {
 276         i2c_del_driver(&pcf8583_driver);
 277 }
 278
 279 module_init(pcf8583_init);
 280 module_exit(pcf8583_exit);
 281
 282 MODULE_AUTHOR("Russell King");
 283 MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
 284 MODULE_LICENSE("GPL");