G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 1 | /* |
| 2 | * drivers/rtc/rtc-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 | * Converted to the generic RTC susbsystem by G. Liakhovetski (2006) |
| 13 | */ |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/i2c.h> |
| 16 | #include <linux/slab.h> |
| 17 | #include <linux/string.h> |
| 18 | #include <linux/mc146818rtc.h> |
| 19 | #include <linux/init.h> |
| 20 | #include <linux/errno.h> |
| 21 | #include <linux/bcd.h> |
| 22 | |
| 23 | struct rtc_mem { |
| 24 | unsigned int loc; |
| 25 | unsigned int nr; |
| 26 | unsigned char *data; |
| 27 | }; |
| 28 | |
| 29 | struct pcf8583 { |
| 30 | struct i2c_client client; |
| 31 | struct rtc_device *rtc; |
| 32 | unsigned char ctrl; |
| 33 | }; |
| 34 | |
| 35 | #define CTRL_STOP 0x80 |
| 36 | #define CTRL_HOLD 0x40 |
| 37 | #define CTRL_32KHZ 0x00 |
| 38 | #define CTRL_MASK 0x08 |
| 39 | #define CTRL_ALARMEN 0x04 |
| 40 | #define CTRL_ALARM 0x02 |
| 41 | #define CTRL_TIMER 0x01 |
| 42 | |
Jean Delvare | 922539a | 2008-01-27 18:14:47 +0100 | [diff] [blame] | 43 | static const unsigned short normal_i2c[] = { 0x50, I2C_CLIENT_END }; |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 44 | |
| 45 | /* Module parameters */ |
| 46 | I2C_CLIENT_INSMOD; |
| 47 | |
| 48 | static struct i2c_driver pcf8583_driver; |
| 49 | |
| 50 | #define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl |
| 51 | #define set_ctrl(x, v) get_ctrl(x) = v |
| 52 | |
| 53 | #define CMOS_YEAR (64 + 128) |
| 54 | #define CMOS_CHECKSUM (63) |
| 55 | |
| 56 | static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt) |
| 57 | { |
| 58 | unsigned char buf[8], addr[1] = { 1 }; |
| 59 | struct i2c_msg msgs[2] = { |
| 60 | { |
| 61 | .addr = client->addr, |
| 62 | .flags = 0, |
| 63 | .len = 1, |
| 64 | .buf = addr, |
| 65 | }, { |
| 66 | .addr = client->addr, |
| 67 | .flags = I2C_M_RD, |
| 68 | .len = 6, |
| 69 | .buf = buf, |
| 70 | } |
| 71 | }; |
| 72 | int ret; |
| 73 | |
| 74 | memset(buf, 0, sizeof(buf)); |
| 75 | |
| 76 | ret = i2c_transfer(client->adapter, msgs, 2); |
| 77 | if (ret == 2) { |
| 78 | dt->tm_year = buf[4] >> 6; |
| 79 | dt->tm_wday = buf[5] >> 5; |
| 80 | |
| 81 | buf[4] &= 0x3f; |
| 82 | buf[5] &= 0x1f; |
| 83 | |
Russell King | f5e5b73 | 2007-03-04 20:12:07 +0000 | [diff] [blame] | 84 | dt->tm_sec = BCD2BIN(buf[1]); |
| 85 | dt->tm_min = BCD2BIN(buf[2]); |
| 86 | dt->tm_hour = BCD2BIN(buf[3]); |
| 87 | dt->tm_mday = BCD2BIN(buf[4]); |
Russell King | 0ed8f21 | 2007-03-04 20:13:13 +0000 | [diff] [blame] | 88 | dt->tm_mon = BCD2BIN(buf[5]) - 1; |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 89 | } |
| 90 | |
| 91 | return ret == 2 ? 0 : -EIO; |
| 92 | } |
| 93 | |
| 94 | static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo) |
| 95 | { |
| 96 | unsigned char buf[8]; |
| 97 | int ret, len = 6; |
| 98 | |
| 99 | buf[0] = 0; |
| 100 | buf[1] = get_ctrl(client) | 0x80; |
| 101 | buf[2] = 0; |
Russell King | f5e5b73 | 2007-03-04 20:12:07 +0000 | [diff] [blame] | 102 | buf[3] = BIN2BCD(dt->tm_sec); |
| 103 | buf[4] = BIN2BCD(dt->tm_min); |
| 104 | buf[5] = BIN2BCD(dt->tm_hour); |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 105 | |
| 106 | if (datetoo) { |
| 107 | len = 8; |
Russell King | f5e5b73 | 2007-03-04 20:12:07 +0000 | [diff] [blame] | 108 | buf[6] = BIN2BCD(dt->tm_mday) | (dt->tm_year << 6); |
Russell King | 0ed8f21 | 2007-03-04 20:13:13 +0000 | [diff] [blame] | 109 | buf[7] = BIN2BCD(dt->tm_mon + 1) | (dt->tm_wday << 5); |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 110 | } |
| 111 | |
| 112 | ret = i2c_master_send(client, (char *)buf, len); |
| 113 | if (ret != len) |
| 114 | return -EIO; |
| 115 | |
| 116 | buf[1] = get_ctrl(client); |
| 117 | ret = i2c_master_send(client, (char *)buf, 2); |
| 118 | |
| 119 | return ret == 2 ? 0 : -EIO; |
| 120 | } |
| 121 | |
| 122 | static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl) |
| 123 | { |
| 124 | *ctrl = get_ctrl(client); |
| 125 | return 0; |
| 126 | } |
| 127 | |
| 128 | static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl) |
| 129 | { |
| 130 | unsigned char buf[2]; |
| 131 | |
| 132 | buf[0] = 0; |
| 133 | buf[1] = *ctrl; |
| 134 | set_ctrl(client, *ctrl); |
| 135 | |
| 136 | return i2c_master_send(client, (char *)buf, 2); |
| 137 | } |
| 138 | |
| 139 | static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem) |
| 140 | { |
| 141 | unsigned char addr[1]; |
| 142 | struct i2c_msg msgs[2] = { |
| 143 | { |
| 144 | .addr = client->addr, |
| 145 | .flags = 0, |
| 146 | .len = 1, |
| 147 | .buf = addr, |
| 148 | }, { |
| 149 | .addr = client->addr, |
| 150 | .flags = I2C_M_RD, |
| 151 | .len = mem->nr, |
| 152 | .buf = mem->data, |
| 153 | } |
| 154 | }; |
| 155 | |
| 156 | if (mem->loc < 8) |
| 157 | return -EINVAL; |
| 158 | |
| 159 | addr[0] = mem->loc; |
| 160 | |
| 161 | return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO; |
| 162 | } |
| 163 | |
| 164 | static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem) |
| 165 | { |
Jean Delvare | 037e291 | 2008-02-06 01:38:41 -0800 | [diff] [blame] | 166 | unsigned char buf[9]; |
| 167 | int ret; |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 168 | |
Jean Delvare | 037e291 | 2008-02-06 01:38:41 -0800 | [diff] [blame] | 169 | if (mem->loc < 8 || mem->nr > 8) |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 170 | return -EINVAL; |
| 171 | |
Jean Delvare | 037e291 | 2008-02-06 01:38:41 -0800 | [diff] [blame] | 172 | buf[0] = mem->loc; |
| 173 | memcpy(buf + 1, mem->data, mem->nr); |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 174 | |
Jean Delvare | 037e291 | 2008-02-06 01:38:41 -0800 | [diff] [blame] | 175 | ret = i2c_master_send(client, buf, mem->nr + 1); |
| 176 | return ret == mem->nr + 1 ? 0 : -EIO; |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 177 | } |
| 178 | |
| 179 | static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm) |
| 180 | { |
| 181 | struct i2c_client *client = to_i2c_client(dev); |
| 182 | unsigned char ctrl, year[2]; |
| 183 | struct rtc_mem mem = { CMOS_YEAR, sizeof(year), year }; |
| 184 | int real_year, year_offset, err; |
| 185 | |
| 186 | /* |
| 187 | * Ensure that the RTC is running. |
| 188 | */ |
| 189 | pcf8583_get_ctrl(client, &ctrl); |
| 190 | if (ctrl & (CTRL_STOP | CTRL_HOLD)) { |
| 191 | unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD); |
| 192 | |
| 193 | printk(KERN_WARNING "RTC: resetting control %02x -> %02x\n", |
| 194 | ctrl, new_ctrl); |
| 195 | |
| 196 | if ((err = pcf8583_set_ctrl(client, &new_ctrl)) < 0) |
| 197 | return err; |
| 198 | } |
| 199 | |
| 200 | if (pcf8583_get_datetime(client, tm) || |
| 201 | pcf8583_read_mem(client, &mem)) |
| 202 | return -EIO; |
| 203 | |
| 204 | real_year = year[0]; |
| 205 | |
| 206 | /* |
| 207 | * The RTC year holds the LSB two bits of the current |
| 208 | * year, which should reflect the LSB two bits of the |
| 209 | * CMOS copy of the year. Any difference indicates |
| 210 | * that we have to correct the CMOS version. |
| 211 | */ |
| 212 | year_offset = tm->tm_year - (real_year & 3); |
| 213 | if (year_offset < 0) |
| 214 | /* |
| 215 | * RTC year wrapped. Adjust it appropriately. |
| 216 | */ |
| 217 | year_offset += 4; |
| 218 | |
Russell King | 0ed8f21 | 2007-03-04 20:13:13 +0000 | [diff] [blame] | 219 | tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900; |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 220 | |
| 221 | return 0; |
| 222 | } |
| 223 | |
| 224 | static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm) |
| 225 | { |
| 226 | struct i2c_client *client = to_i2c_client(dev); |
| 227 | unsigned char year[2], chk; |
| 228 | struct rtc_mem cmos_year = { CMOS_YEAR, sizeof(year), year }; |
| 229 | struct rtc_mem cmos_check = { CMOS_CHECKSUM, 1, &chk }; |
Russell King | 0ed8f21 | 2007-03-04 20:13:13 +0000 | [diff] [blame] | 230 | unsigned int proper_year = tm->tm_year + 1900; |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 231 | int ret; |
| 232 | |
| 233 | /* |
| 234 | * The RTC's own 2-bit year must reflect the least |
| 235 | * significant two bits of the CMOS year. |
| 236 | */ |
| 237 | |
| 238 | ret = pcf8583_set_datetime(client, tm, 1); |
| 239 | if (ret) |
| 240 | return ret; |
| 241 | |
| 242 | ret = pcf8583_read_mem(client, &cmos_check); |
| 243 | if (ret) |
| 244 | return ret; |
| 245 | |
| 246 | ret = pcf8583_read_mem(client, &cmos_year); |
| 247 | if (ret) |
| 248 | return ret; |
| 249 | |
| 250 | chk -= year[1] + year[0]; |
| 251 | |
Russell King | 0ed8f21 | 2007-03-04 20:13:13 +0000 | [diff] [blame] | 252 | year[1] = proper_year / 100; |
| 253 | year[0] = proper_year % 100; |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 254 | |
| 255 | chk += year[1] + year[0]; |
| 256 | |
| 257 | ret = pcf8583_write_mem(client, &cmos_year); |
| 258 | |
| 259 | if (ret) |
| 260 | return ret; |
| 261 | |
| 262 | ret = pcf8583_write_mem(client, &cmos_check); |
| 263 | |
| 264 | return ret; |
| 265 | } |
| 266 | |
David Brownell | ff8371a | 2006-09-30 23:28:17 -0700 | [diff] [blame] | 267 | static const struct rtc_class_ops pcf8583_rtc_ops = { |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 268 | .read_time = pcf8583_rtc_read_time, |
| 269 | .set_time = pcf8583_rtc_set_time, |
| 270 | }; |
| 271 | |
| 272 | static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind); |
| 273 | |
| 274 | static int pcf8583_attach(struct i2c_adapter *adap) |
| 275 | { |
| 276 | return i2c_probe(adap, &addr_data, pcf8583_probe); |
| 277 | } |
| 278 | |
| 279 | static int pcf8583_detach(struct i2c_client *client) |
| 280 | { |
| 281 | int err; |
| 282 | struct pcf8583 *pcf = i2c_get_clientdata(client); |
| 283 | struct rtc_device *rtc = pcf->rtc; |
| 284 | |
| 285 | if (rtc) |
| 286 | rtc_device_unregister(rtc); |
| 287 | |
| 288 | if ((err = i2c_detach_client(client))) |
| 289 | return err; |
| 290 | |
| 291 | kfree(pcf); |
| 292 | return 0; |
| 293 | } |
| 294 | |
| 295 | static struct i2c_driver pcf8583_driver = { |
| 296 | .driver = { |
| 297 | .name = "pcf8583", |
| 298 | }, |
| 299 | .id = I2C_DRIVERID_PCF8583, |
| 300 | .attach_adapter = pcf8583_attach, |
| 301 | .detach_client = pcf8583_detach, |
| 302 | }; |
| 303 | |
| 304 | static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind) |
| 305 | { |
| 306 | struct pcf8583 *pcf; |
| 307 | struct i2c_client *client; |
| 308 | struct rtc_device *rtc; |
| 309 | unsigned char buf[1], ad[1] = { 0 }; |
| 310 | int err; |
| 311 | struct i2c_msg msgs[2] = { |
| 312 | { |
| 313 | .addr = addr, |
| 314 | .flags = 0, |
| 315 | .len = 1, |
| 316 | .buf = ad, |
| 317 | }, { |
| 318 | .addr = addr, |
| 319 | .flags = I2C_M_RD, |
| 320 | .len = 1, |
| 321 | .buf = buf, |
| 322 | } |
| 323 | }; |
| 324 | |
Jean Delvare | c018664 | 2007-10-16 01:28:18 -0700 | [diff] [blame] | 325 | if (!i2c_check_functionality(adap, I2C_FUNC_I2C)) |
| 326 | return 0; |
| 327 | |
G. Liakhovetski | 9c0c570 | 2006-06-25 05:48:18 -0700 | [diff] [blame] | 328 | pcf = kzalloc(sizeof(*pcf), GFP_KERNEL); |
| 329 | if (!pcf) |
| 330 | return -ENOMEM; |
| 331 | |
| 332 | client = &pcf->client; |
| 333 | |
| 334 | client->addr = addr; |
| 335 | client->adapter = adap; |
| 336 | client->driver = &pcf8583_driver; |
| 337 | |
| 338 | strlcpy(client->name, pcf8583_driver.driver.name, I2C_NAME_SIZE); |
| 339 | |
| 340 | if (i2c_transfer(client->adapter, msgs, 2) != 2) { |
| 341 | err = -EIO; |
| 342 | goto exit_kfree; |
| 343 | } |
| 344 | |
| 345 | err = i2c_attach_client(client); |
| 346 | |
| 347 | if (err) |
| 348 | goto exit_kfree; |
| 349 | |
| 350 | rtc = rtc_device_register(pcf8583_driver.driver.name, &client->dev, |
| 351 | &pcf8583_rtc_ops, THIS_MODULE); |
| 352 | |
| 353 | if (IS_ERR(rtc)) { |
| 354 | err = PTR_ERR(rtc); |
| 355 | goto exit_detach; |
| 356 | } |
| 357 | |
| 358 | pcf->rtc = rtc; |
| 359 | i2c_set_clientdata(client, pcf); |
| 360 | set_ctrl(client, buf[0]); |
| 361 | |
| 362 | return 0; |
| 363 | |
| 364 | exit_detach: |
| 365 | i2c_detach_client(client); |
| 366 | |
| 367 | exit_kfree: |
| 368 | kfree(pcf); |
| 369 | |
| 370 | return err; |
| 371 | } |
| 372 | |
| 373 | static __init int pcf8583_init(void) |
| 374 | { |
| 375 | return i2c_add_driver(&pcf8583_driver); |
| 376 | } |
| 377 | |
| 378 | static __exit void pcf8583_exit(void) |
| 379 | { |
| 380 | i2c_del_driver(&pcf8583_driver); |
| 381 | } |
| 382 | |
| 383 | module_init(pcf8583_init); |
| 384 | module_exit(pcf8583_exit); |
| 385 | |
| 386 | MODULE_AUTHOR("Russell King"); |
| 387 | MODULE_DESCRIPTION("PCF8583 I2C RTC driver"); |
| 388 | MODULE_LICENSE("GPL"); |