1 /* 2 * An rtc/i2c driver for the Dallas DS1672 3 * Copyright 2005-06 Tower Technologies 4 * 5 * Author: Alessandro Zummo <a.zummo@towertech.it> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12 #include <linux/module.h> 13 #include <linux/i2c.h> 14 #include <linux/rtc.h> 15 16 #define DRV_VERSION "0.3" 17 18 /* Addresses to scan: none. This chip cannot be detected. */ 19 static unsigned short normal_i2c[] = { I2C_CLIENT_END }; 20 21 /* Insmod parameters */ 22 I2C_CLIENT_INSMOD; 23 24 /* Registers */ 25 26 #define DS1672_REG_CNT_BASE 0 27 #define DS1672_REG_CONTROL 4 28 #define DS1672_REG_TRICKLE 5 29 30 #define DS1672_REG_CONTROL_EOSC 0x80 31 32 /* Prototypes */ 33 static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind); 34 35 /* 36 * In the routines that deal directly with the ds1672 hardware, we use 37 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch 38 * Epoch is initialized as 2000. Time is set to UTC. 39 */ 40 static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm) 41 { 42 unsigned long time; 43 unsigned char addr = DS1672_REG_CNT_BASE; 44 unsigned char buf[4]; 45 46 struct i2c_msg msgs[] = { 47 { client->addr, 0, 1, &addr }, /* setup read ptr */ 48 { client->addr, I2C_M_RD, 4, buf }, /* read date */ 49 }; 50 51 /* read date registers */ 52 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 53 dev_err(&client->dev, "%s: read error\n", __FUNCTION__); 54 return -EIO; 55 } 56 57 dev_dbg(&client->dev, 58 "%s: raw read data - counters=%02x,%02x,%02x,%02x\n" 59 __FUNCTION__, buf[0], buf[1], buf[2], buf[3]); 60 61 time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; 62 63 rtc_time_to_tm(time, tm); 64 65 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 66 "mday=%d, mon=%d, year=%d, wday=%d\n", 67 __FUNCTION__, tm->tm_sec, tm->tm_min, tm->tm_hour, 68 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 69 70 return 0; 71 } 72 73 static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs) 74 { 75 int xfer; 76 unsigned char buf[6]; 77 78 buf[0] = DS1672_REG_CNT_BASE; 79 buf[1] = secs & 0x000000FF; 80 buf[2] = (secs & 0x0000FF00) >> 8; 81 buf[3] = (secs & 0x00FF0000) >> 16; 82 buf[4] = (secs & 0xFF000000) >> 24; 83 buf[5] = 0; /* set control reg to enable counting */ 84 85 xfer = i2c_master_send(client, buf, 6); 86 if (xfer != 6) { 87 dev_err(&client->dev, "%s: send: %d\n", __FUNCTION__, xfer); 88 return -EIO; 89 } 90 91 return 0; 92 } 93 94 static int ds1672_set_datetime(struct i2c_client *client, struct rtc_time *tm) 95 { 96 unsigned long secs; 97 98 dev_dbg(&client->dev, 99 "%s: secs=%d, mins=%d, hours=%d, ", 100 "mday=%d, mon=%d, year=%d, wday=%d\n", 101 __FUNCTION__, 102 tm->tm_sec, tm->tm_min, tm->tm_hour, 103 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 104 105 rtc_tm_to_time(tm, &secs); 106 107 return ds1672_set_mmss(client, secs); 108 } 109 110 static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm) 111 { 112 return ds1672_get_datetime(to_i2c_client(dev), tm); 113 } 114 115 static int ds1672_rtc_set_time(struct device *dev, struct rtc_time *tm) 116 { 117 return ds1672_set_datetime(to_i2c_client(dev), tm); 118 } 119 120 static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs) 121 { 122 return ds1672_set_mmss(to_i2c_client(dev), secs); 123 } 124 125 static int ds1672_get_control(struct i2c_client *client, u8 *status) 126 { 127 unsigned char addr = DS1672_REG_CONTROL; 128 129 struct i2c_msg msgs[] = { 130 { client->addr, 0, 1, &addr }, /* setup read ptr */ 131 { client->addr, I2C_M_RD, 1, status }, /* read control */ 132 }; 133 134 /* read control register */ 135 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 136 dev_err(&client->dev, "%s: read error\n", __FUNCTION__); 137 return -EIO; 138 } 139 140 return 0; 141 } 142 143 /* following are the sysfs callback functions */ 144 static ssize_t show_control(struct device *dev, struct device_attribute *attr, char *buf) 145 { 146 struct i2c_client *client = to_i2c_client(dev); 147 u8 control; 148 int err; 149 150 err = ds1672_get_control(client, &control); 151 if (err) 152 return err; 153 154 return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC) 155 ? "disabled" : "enabled"); 156 } 157 static DEVICE_ATTR(control, S_IRUGO, show_control, NULL); 158 159 static const struct rtc_class_ops ds1672_rtc_ops = { 160 .read_time = ds1672_rtc_read_time, 161 .set_time = ds1672_rtc_set_time, 162 .set_mmss = ds1672_rtc_set_mmss, 163 }; 164 165 static int ds1672_attach(struct i2c_adapter *adapter) 166 { 167 return i2c_probe(adapter, &addr_data, ds1672_probe); 168 } 169 170 static int ds1672_detach(struct i2c_client *client) 171 { 172 int err; 173 struct rtc_device *rtc = i2c_get_clientdata(client); 174 175 if (rtc) 176 rtc_device_unregister(rtc); 177 178 if ((err = i2c_detach_client(client))) 179 return err; 180 181 kfree(client); 182 183 return 0; 184 } 185 186 static struct i2c_driver ds1672_driver = { 187 .driver = { 188 .name = "ds1672", 189 }, 190 .id = I2C_DRIVERID_DS1672, 191 .attach_adapter = &ds1672_attach, 192 .detach_client = &ds1672_detach, 193 }; 194 195 static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind) 196 { 197 int err = 0; 198 u8 control; 199 struct i2c_client *client; 200 struct rtc_device *rtc; 201 202 dev_dbg(&adapter->dev, "%s\n", __FUNCTION__); 203 204 if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) { 205 err = -ENODEV; 206 goto exit; 207 } 208 209 if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) { 210 err = -ENOMEM; 211 goto exit; 212 } 213 214 /* I2C client */ 215 client->addr = address; 216 client->driver = &ds1672_driver; 217 client->adapter = adapter; 218 219 strlcpy(client->name, ds1672_driver.driver.name, I2C_NAME_SIZE); 220 221 /* Inform the i2c layer */ 222 if ((err = i2c_attach_client(client))) 223 goto exit_kfree; 224 225 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 226 227 rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev, 228 &ds1672_rtc_ops, THIS_MODULE); 229 230 if (IS_ERR(rtc)) { 231 err = PTR_ERR(rtc); 232 goto exit_detach; 233 } 234 235 i2c_set_clientdata(client, rtc); 236 237 /* read control register */ 238 err = ds1672_get_control(client, &control); 239 if (err) 240 goto exit_detach; 241 242 if (control & DS1672_REG_CONTROL_EOSC) 243 dev_warn(&client->dev, "Oscillator not enabled. " 244 "Set time to enable.\n"); 245 246 /* Register sysfs hooks */ 247 device_create_file(&client->dev, &dev_attr_control); 248 249 return 0; 250 251 exit_detach: 252 i2c_detach_client(client); 253 254 exit_kfree: 255 kfree(client); 256 257 exit: 258 return err; 259 } 260 261 static int __init ds1672_init(void) 262 { 263 return i2c_add_driver(&ds1672_driver); 264 } 265 266 static void __exit ds1672_exit(void) 267 { 268 i2c_del_driver(&ds1672_driver); 269 } 270 271 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 272 MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver"); 273 MODULE_LICENSE("GPL"); 274 MODULE_VERSION(DRV_VERSION); 275 276 module_init(ds1672_init); 277 module_exit(ds1672_exit); 278