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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/i2c.h>
  13 #include <linux/slab.h>
  14 #include <linux/string.h>
  15 #include <linux/mc146818rtc.h>
  16 #include <linux/init.h>
  17 #include <linux/errno.h>
  18 #include <linux/bcd.h>
  19
  20 #include "pcf8583.h"
  21
  22 static struct i2c_driver pcf8583_driver;
  23
  24 static unsigned short ignore[] = { I2C_CLIENT_END };
  25 static unsigned short normal_addr[] = { 0x50, I2C_CLIENT_END };
  26 static unsigned short *forces[] = { NULL };
  27
  28 static struct i2c_client_address_data addr_data = {
  29         .normal_i2c             = normal_addr,
  30         .probe                  = ignore,
  31         .ignore                 = ignore,
  32         .forces                 = forces,
  33 };
  34
  35 #define DAT(x) ((unsigned int)(x->dev.driver_data))
  36
  37 static int
  38 pcf8583_attach(struct i2c_adapter *adap, int addr, int kind)
  39 {
  40         struct i2c_client *c;
  41         unsigned char buf[1], ad[1] = { 0 };
  42         struct i2c_msg msgs[2] = {
  43                 { addr, 0,        1, ad  },
  44                 { addr, I2C_M_RD, 1, buf }
  45         };
  46
  47         c = kmalloc(sizeof(*c), GFP_KERNEL);
  48         if (!c)
  49                 return -ENOMEM;
  50
  51         memset(c, 0, sizeof(*c));
  52         c->addr         = addr;
  53         c->adapter      = adap;
  54         c->driver       = &pcf8583_driver;
  55
  56         if (i2c_transfer(c->adapter, msgs, 2) == 2)
  57                 DAT(c) = buf[0];
  58
  59         return i2c_attach_client(c);
  60 }
  61
  62 static int
  63 pcf8583_probe(struct i2c_adapter *adap)
  64 {
  65         return i2c_probe(adap, &addr_data, pcf8583_attach);
  66 }
  67
  68 static int
  69 pcf8583_detach(struct i2c_client *client)
  70 {
  71         i2c_detach_client(client);
  72         kfree(client);
  73         return 0;
  74 }
  75
  76 static int
  77 pcf8583_get_datetime(struct i2c_client *client, struct rtc_tm *dt)
  78 {
  79         unsigned char buf[8], addr[1] = { 1 };
  80         struct i2c_msg msgs[2] = {
  81                 { client->addr, 0,        1, addr },
  82                 { client->addr, I2C_M_RD, 6, buf  }
  83         };
  84         int ret = -EIO;
  85
  86         memset(buf, 0, sizeof(buf));
  87
  88         ret = i2c_transfer(client->adapter, msgs, 2);
  89         if (ret == 2) {
  90                 dt->year_off = buf[4] >> 6;
  91                 dt->wday     = buf[5] >> 5;
  92
  93                 buf[4] &= 0x3f;
  94                 buf[5] &= 0x1f;
  95
  96                 dt->cs       = BCD_TO_BIN(buf[0]);
  97                 dt->secs     = BCD_TO_BIN(buf[1]);
  98                 dt->mins     = BCD_TO_BIN(buf[2]);
  99                 dt->hours    = BCD_TO_BIN(buf[3]);
 100                 dt->mday     = BCD_TO_BIN(buf[4]);
 101                 dt->mon      = BCD_TO_BIN(buf[5]);
 102
 103                 ret = 0;
 104         }
 105
 106         return ret;
 107 }
 108
 109 static int
 110 pcf8583_set_datetime(struct i2c_client *client, struct rtc_tm *dt, int datetoo)
 111 {
 112         unsigned char buf[8];
 113         int ret, len = 6;
 114
 115         buf[0] = 0;
 116         buf[1] = DAT(client) | 0x80;
 117         buf[2] = BIN_TO_BCD(dt->cs);
 118         buf[3] = BIN_TO_BCD(dt->secs);
 119         buf[4] = BIN_TO_BCD(dt->mins);
 120         buf[5] = BIN_TO_BCD(dt->hours);
 121
 122         if (datetoo) {
 123                 len = 8;
 124                 buf[6] = BIN_TO_BCD(dt->mday) | (dt->year_off << 6);
 125                 buf[7] = BIN_TO_BCD(dt->mon)  | (dt->wday << 5);
 126         }
 127
 128         ret = i2c_master_send(client, (char *)buf, len);
 129         if (ret == len)
 130                 ret = 0;
 131
 132         buf[1] = DAT(client);
 133         i2c_master_send(client, (char *)buf, 2);
 134
 135         return ret;
 136 }
 137
 138 static int
 139 pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)
 140 {
 141         *ctrl = DAT(client);
 142         return 0;
 143 }
 144
 145 static int
 146 pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl)
 147 {
 148         unsigned char buf[2];
 149
 150         buf[0] = 0;
 151         buf[1] = *ctrl;
 152         DAT(client) = *ctrl;
 153
 154         return i2c_master_send(client, (char *)buf, 2);
 155 }
 156
 157 static int
 158 pcf8583_read_mem(struct i2c_client *client, struct mem *mem)
 159 {
 160         unsigned char addr[1];
 161         struct i2c_msg msgs[2] = {
 162                 { client->addr, 0,        1, addr },
 163                 { client->addr, I2C_M_RD, 0, mem->data }
 164         };
 165
 166         if (mem->loc < 8)
 167                 return -EINVAL;
 168
 169         addr[0] = mem->loc;
 170         msgs[1].len = mem->nr;
 171
 172         return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
 173 }
 174
 175 static int
 176 pcf8583_write_mem(struct i2c_client *client, struct mem *mem)
 177 {
 178         unsigned char addr[1];
 179         struct i2c_msg msgs[2] = {
 180                 { client->addr, 0, 1, addr },
 181                 { client->addr, 0, 0, mem->data }
 182         };
 183
 184         if (mem->loc < 8)
 185                 return -EINVAL;
 186
 187         addr[0] = mem->loc;
 188         msgs[1].len = mem->nr;
 189
 190         return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
 191 }
 192
 193 static int
 194 pcf8583_command(struct i2c_client *client, unsigned int cmd, void *arg)
 195 {
 196         switch (cmd) {
 197         case RTC_GETDATETIME:
 198                 return pcf8583_get_datetime(client, arg);
 199
 200         case RTC_SETTIME:
 201                 return pcf8583_set_datetime(client, arg, 0);
 202
 203         case RTC_SETDATETIME:
 204                 return pcf8583_set_datetime(client, arg, 1);
 205
 206         case RTC_GETCTRL:
 207                 return pcf8583_get_ctrl(client, arg);
 208
 209         case RTC_SETCTRL:
 210                 return pcf8583_set_ctrl(client, arg);
 211
 212         case MEM_READ:
 213                 return pcf8583_read_mem(client, arg);
 214
 215         case MEM_WRITE:
 216                 return pcf8583_write_mem(client, arg);
 217
 218         default:
 219                 return -EINVAL;
 220         }
 221 }
 222
 223 static struct i2c_driver pcf8583_driver = {
 224         .name           = "PCF8583",
 225         .id             = I2C_DRIVERID_PCF8583,
 226         .flags          = I2C_DF_NOTIFY,
 227         .attach_adapter = pcf8583_probe,
 228         .detach_client  = pcf8583_detach,
 229         .command        = pcf8583_command
 230 };
 231
 232 static __init int pcf8583_init(void)
 233 {
 234         return i2c_add_driver(&pcf8583_driver);
 235 }
 236
 237 __initcall(pcf8583_init);