1edf1aaa3SAlessandro Zummo /* 2edf1aaa3SAlessandro Zummo * An rtc/i2c driver for the Dallas DS1672 3edf1aaa3SAlessandro Zummo * Copyright 2005 Alessandro Zummo 4edf1aaa3SAlessandro Zummo * 5edf1aaa3SAlessandro Zummo * This program is free software; you can redistribute it and/or modify 6edf1aaa3SAlessandro Zummo * it under the terms of the GNU General Public License version 2 as 7edf1aaa3SAlessandro Zummo * published by the Free Software Foundation. 8edf1aaa3SAlessandro Zummo */ 9edf1aaa3SAlessandro Zummo 10edf1aaa3SAlessandro Zummo #include <linux/module.h> 11edf1aaa3SAlessandro Zummo #include <linux/i2c.h> 12edf1aaa3SAlessandro Zummo #include <linux/rtc.h> 13edf1aaa3SAlessandro Zummo 14edf1aaa3SAlessandro Zummo #define DRV_VERSION "0.2" 15edf1aaa3SAlessandro Zummo 16edf1aaa3SAlessandro Zummo /* Addresses to scan: none. This chip cannot be detected. */ 17edf1aaa3SAlessandro Zummo static unsigned short normal_i2c[] = { I2C_CLIENT_END }; 18edf1aaa3SAlessandro Zummo 19edf1aaa3SAlessandro Zummo /* Insmod parameters */ 20edf1aaa3SAlessandro Zummo I2C_CLIENT_INSMOD; 21edf1aaa3SAlessandro Zummo 22edf1aaa3SAlessandro Zummo /* Registers */ 23edf1aaa3SAlessandro Zummo 24edf1aaa3SAlessandro Zummo #define DS1672_REG_CNT_BASE 0 25edf1aaa3SAlessandro Zummo #define DS1672_REG_CONTROL 4 26*8a95b252SKumar Gala #define DS1672_REG_CONTROL_EOSC 0x80 27edf1aaa3SAlessandro Zummo #define DS1672_REG_TRICKLE 5 28edf1aaa3SAlessandro Zummo 29edf1aaa3SAlessandro Zummo 30edf1aaa3SAlessandro Zummo /* Prototypes */ 31edf1aaa3SAlessandro Zummo static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind); 32edf1aaa3SAlessandro Zummo 33edf1aaa3SAlessandro Zummo /* 34edf1aaa3SAlessandro Zummo * In the routines that deal directly with the ds1672 hardware, we use 35edf1aaa3SAlessandro Zummo * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch 36edf1aaa3SAlessandro Zummo * Epoch is initialized as 2000. Time is set to UTC. 37edf1aaa3SAlessandro Zummo */ 38edf1aaa3SAlessandro Zummo static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm) 39edf1aaa3SAlessandro Zummo { 40edf1aaa3SAlessandro Zummo unsigned long time; 41edf1aaa3SAlessandro Zummo unsigned char addr = DS1672_REG_CNT_BASE; 42edf1aaa3SAlessandro Zummo unsigned char buf[4]; 43edf1aaa3SAlessandro Zummo 44edf1aaa3SAlessandro Zummo struct i2c_msg msgs[] = { 45edf1aaa3SAlessandro Zummo { client->addr, 0, 1, &addr }, /* setup read ptr */ 46edf1aaa3SAlessandro Zummo { client->addr, I2C_M_RD, 4, buf }, /* read date */ 47edf1aaa3SAlessandro Zummo }; 48edf1aaa3SAlessandro Zummo 49edf1aaa3SAlessandro Zummo /* read date registers */ 50edf1aaa3SAlessandro Zummo if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 51edf1aaa3SAlessandro Zummo dev_err(&client->dev, "%s: read error\n", __FUNCTION__); 52edf1aaa3SAlessandro Zummo return -EIO; 53edf1aaa3SAlessandro Zummo } 54edf1aaa3SAlessandro Zummo 55edf1aaa3SAlessandro Zummo dev_dbg(&client->dev, 56edf1aaa3SAlessandro Zummo "%s: raw read data - counters=%02x,%02x,%02x,%02x\n" 57edf1aaa3SAlessandro Zummo __FUNCTION__, 58edf1aaa3SAlessandro Zummo buf[0], buf[1], buf[2], buf[3]); 59edf1aaa3SAlessandro Zummo 60edf1aaa3SAlessandro Zummo time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; 61edf1aaa3SAlessandro Zummo 62edf1aaa3SAlessandro Zummo rtc_time_to_tm(time, tm); 63edf1aaa3SAlessandro Zummo 64edf1aaa3SAlessandro Zummo dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 65edf1aaa3SAlessandro Zummo "mday=%d, mon=%d, year=%d, wday=%d\n", 66edf1aaa3SAlessandro Zummo __FUNCTION__, 67edf1aaa3SAlessandro Zummo tm->tm_sec, tm->tm_min, tm->tm_hour, 68edf1aaa3SAlessandro Zummo tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 69edf1aaa3SAlessandro Zummo 70edf1aaa3SAlessandro Zummo return 0; 71edf1aaa3SAlessandro Zummo } 72edf1aaa3SAlessandro Zummo 73edf1aaa3SAlessandro Zummo static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs) 74edf1aaa3SAlessandro Zummo { 75edf1aaa3SAlessandro Zummo int xfer; 76*8a95b252SKumar Gala unsigned char buf[6]; 77edf1aaa3SAlessandro Zummo 78edf1aaa3SAlessandro Zummo buf[0] = DS1672_REG_CNT_BASE; 79edf1aaa3SAlessandro Zummo buf[1] = secs & 0x000000FF; 80edf1aaa3SAlessandro Zummo buf[2] = (secs & 0x0000FF00) >> 8; 81edf1aaa3SAlessandro Zummo buf[3] = (secs & 0x00FF0000) >> 16; 82edf1aaa3SAlessandro Zummo buf[4] = (secs & 0xFF000000) >> 24; 83*8a95b252SKumar Gala buf[5] = 0; /* set control reg to enable counting */ 84edf1aaa3SAlessandro Zummo 85*8a95b252SKumar Gala xfer = i2c_master_send(client, buf, 6); 86*8a95b252SKumar Gala if (xfer != 6) { 87edf1aaa3SAlessandro Zummo dev_err(&client->dev, "%s: send: %d\n", __FUNCTION__, xfer); 88edf1aaa3SAlessandro Zummo return -EIO; 89edf1aaa3SAlessandro Zummo } 90edf1aaa3SAlessandro Zummo 91edf1aaa3SAlessandro Zummo return 0; 92edf1aaa3SAlessandro Zummo } 93edf1aaa3SAlessandro Zummo 94edf1aaa3SAlessandro Zummo static int ds1672_set_datetime(struct i2c_client *client, struct rtc_time *tm) 95edf1aaa3SAlessandro Zummo { 96edf1aaa3SAlessandro Zummo unsigned long secs; 97edf1aaa3SAlessandro Zummo 98edf1aaa3SAlessandro Zummo dev_dbg(&client->dev, 99edf1aaa3SAlessandro Zummo "%s: secs=%d, mins=%d, hours=%d, ", 100edf1aaa3SAlessandro Zummo "mday=%d, mon=%d, year=%d, wday=%d\n", 101edf1aaa3SAlessandro Zummo __FUNCTION__, 102edf1aaa3SAlessandro Zummo tm->tm_sec, tm->tm_min, tm->tm_hour, 103edf1aaa3SAlessandro Zummo tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 104edf1aaa3SAlessandro Zummo 105edf1aaa3SAlessandro Zummo rtc_tm_to_time(tm, &secs); 106edf1aaa3SAlessandro Zummo 107edf1aaa3SAlessandro Zummo return ds1672_set_mmss(client, secs); 108edf1aaa3SAlessandro Zummo } 109edf1aaa3SAlessandro Zummo 110edf1aaa3SAlessandro Zummo static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm) 111edf1aaa3SAlessandro Zummo { 112edf1aaa3SAlessandro Zummo return ds1672_get_datetime(to_i2c_client(dev), tm); 113edf1aaa3SAlessandro Zummo } 114edf1aaa3SAlessandro Zummo 115edf1aaa3SAlessandro Zummo static int ds1672_rtc_set_time(struct device *dev, struct rtc_time *tm) 116edf1aaa3SAlessandro Zummo { 117edf1aaa3SAlessandro Zummo return ds1672_set_datetime(to_i2c_client(dev), tm); 118edf1aaa3SAlessandro Zummo } 119edf1aaa3SAlessandro Zummo 120edf1aaa3SAlessandro Zummo static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs) 121edf1aaa3SAlessandro Zummo { 122edf1aaa3SAlessandro Zummo return ds1672_set_mmss(to_i2c_client(dev), secs); 123edf1aaa3SAlessandro Zummo } 124edf1aaa3SAlessandro Zummo 125*8a95b252SKumar Gala static int ds1672_get_control(struct i2c_client *client, u8 *status) 126*8a95b252SKumar Gala { 127*8a95b252SKumar Gala unsigned char addr = DS1672_REG_CONTROL; 128*8a95b252SKumar Gala 129*8a95b252SKumar Gala struct i2c_msg msgs[] = { 130*8a95b252SKumar Gala { client->addr, 0, 1, &addr }, /* setup read ptr */ 131*8a95b252SKumar Gala { client->addr, I2C_M_RD, 1, status }, /* read control */ 132*8a95b252SKumar Gala }; 133*8a95b252SKumar Gala 134*8a95b252SKumar Gala /* read control register */ 135*8a95b252SKumar Gala if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 136*8a95b252SKumar Gala dev_err(&client->dev, "%s: read error\n", __FUNCTION__); 137*8a95b252SKumar Gala return -EIO; 138*8a95b252SKumar Gala } 139*8a95b252SKumar Gala 140*8a95b252SKumar Gala return 0; 141*8a95b252SKumar Gala } 142*8a95b252SKumar Gala 143*8a95b252SKumar Gala /* following are the sysfs callback functions */ 144*8a95b252SKumar Gala static ssize_t show_control(struct device *dev, struct device_attribute *attr, char *buf) 145*8a95b252SKumar Gala { 146*8a95b252SKumar Gala struct i2c_client *client = to_i2c_client(dev); 147*8a95b252SKumar Gala char *state = "enabled"; 148*8a95b252SKumar Gala u8 control; 149*8a95b252SKumar Gala int err; 150*8a95b252SKumar Gala 151*8a95b252SKumar Gala err = ds1672_get_control(client, &control); 152*8a95b252SKumar Gala if (err) 153*8a95b252SKumar Gala return err; 154*8a95b252SKumar Gala 155*8a95b252SKumar Gala if (control & DS1672_REG_CONTROL_EOSC) 156*8a95b252SKumar Gala state = "disabled"; 157*8a95b252SKumar Gala 158*8a95b252SKumar Gala return sprintf(buf, "%s\n", state); 159*8a95b252SKumar Gala } 160*8a95b252SKumar Gala 161*8a95b252SKumar Gala static DEVICE_ATTR(control, S_IRUGO, show_control, NULL); 162*8a95b252SKumar Gala 163edf1aaa3SAlessandro Zummo static struct rtc_class_ops ds1672_rtc_ops = { 164edf1aaa3SAlessandro Zummo .read_time = ds1672_rtc_read_time, 165edf1aaa3SAlessandro Zummo .set_time = ds1672_rtc_set_time, 166edf1aaa3SAlessandro Zummo .set_mmss = ds1672_rtc_set_mmss, 167edf1aaa3SAlessandro Zummo }; 168edf1aaa3SAlessandro Zummo 169edf1aaa3SAlessandro Zummo static int ds1672_attach(struct i2c_adapter *adapter) 170edf1aaa3SAlessandro Zummo { 171edf1aaa3SAlessandro Zummo dev_dbg(&adapter->dev, "%s\n", __FUNCTION__); 172edf1aaa3SAlessandro Zummo return i2c_probe(adapter, &addr_data, ds1672_probe); 173edf1aaa3SAlessandro Zummo } 174edf1aaa3SAlessandro Zummo 175edf1aaa3SAlessandro Zummo static int ds1672_detach(struct i2c_client *client) 176edf1aaa3SAlessandro Zummo { 177edf1aaa3SAlessandro Zummo int err; 178edf1aaa3SAlessandro Zummo struct rtc_device *rtc = i2c_get_clientdata(client); 179edf1aaa3SAlessandro Zummo 180edf1aaa3SAlessandro Zummo dev_dbg(&client->dev, "%s\n", __FUNCTION__); 181edf1aaa3SAlessandro Zummo 182edf1aaa3SAlessandro Zummo if (rtc) 183edf1aaa3SAlessandro Zummo rtc_device_unregister(rtc); 184edf1aaa3SAlessandro Zummo 185edf1aaa3SAlessandro Zummo if ((err = i2c_detach_client(client))) 186edf1aaa3SAlessandro Zummo return err; 187edf1aaa3SAlessandro Zummo 188edf1aaa3SAlessandro Zummo kfree(client); 189edf1aaa3SAlessandro Zummo 190edf1aaa3SAlessandro Zummo return 0; 191edf1aaa3SAlessandro Zummo } 192edf1aaa3SAlessandro Zummo 193edf1aaa3SAlessandro Zummo static struct i2c_driver ds1672_driver = { 194edf1aaa3SAlessandro Zummo .driver = { 195edf1aaa3SAlessandro Zummo .name = "ds1672", 196edf1aaa3SAlessandro Zummo }, 197edf1aaa3SAlessandro Zummo .id = I2C_DRIVERID_DS1672, 198edf1aaa3SAlessandro Zummo .attach_adapter = &ds1672_attach, 199edf1aaa3SAlessandro Zummo .detach_client = &ds1672_detach, 200edf1aaa3SAlessandro Zummo }; 201edf1aaa3SAlessandro Zummo 202edf1aaa3SAlessandro Zummo static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind) 203edf1aaa3SAlessandro Zummo { 204edf1aaa3SAlessandro Zummo int err = 0; 205*8a95b252SKumar Gala u8 control; 206edf1aaa3SAlessandro Zummo struct i2c_client *client; 207edf1aaa3SAlessandro Zummo struct rtc_device *rtc; 208edf1aaa3SAlessandro Zummo 209edf1aaa3SAlessandro Zummo dev_dbg(&adapter->dev, "%s\n", __FUNCTION__); 210edf1aaa3SAlessandro Zummo 211edf1aaa3SAlessandro Zummo if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) { 212edf1aaa3SAlessandro Zummo err = -ENODEV; 213edf1aaa3SAlessandro Zummo goto exit; 214edf1aaa3SAlessandro Zummo } 215edf1aaa3SAlessandro Zummo 216edf1aaa3SAlessandro Zummo if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) { 217edf1aaa3SAlessandro Zummo err = -ENOMEM; 218edf1aaa3SAlessandro Zummo goto exit; 219edf1aaa3SAlessandro Zummo } 220edf1aaa3SAlessandro Zummo 221edf1aaa3SAlessandro Zummo /* I2C client */ 222edf1aaa3SAlessandro Zummo client->addr = address; 223edf1aaa3SAlessandro Zummo client->driver = &ds1672_driver; 224edf1aaa3SAlessandro Zummo client->adapter = adapter; 225edf1aaa3SAlessandro Zummo 226edf1aaa3SAlessandro Zummo strlcpy(client->name, ds1672_driver.driver.name, I2C_NAME_SIZE); 227edf1aaa3SAlessandro Zummo 228edf1aaa3SAlessandro Zummo /* Inform the i2c layer */ 229edf1aaa3SAlessandro Zummo if ((err = i2c_attach_client(client))) 230edf1aaa3SAlessandro Zummo goto exit_kfree; 231edf1aaa3SAlessandro Zummo 232edf1aaa3SAlessandro Zummo dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 233edf1aaa3SAlessandro Zummo 234edf1aaa3SAlessandro Zummo rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev, 235edf1aaa3SAlessandro Zummo &ds1672_rtc_ops, THIS_MODULE); 236edf1aaa3SAlessandro Zummo 237edf1aaa3SAlessandro Zummo if (IS_ERR(rtc)) { 238edf1aaa3SAlessandro Zummo err = PTR_ERR(rtc); 239edf1aaa3SAlessandro Zummo dev_err(&client->dev, 240edf1aaa3SAlessandro Zummo "unable to register the class device\n"); 241edf1aaa3SAlessandro Zummo goto exit_detach; 242edf1aaa3SAlessandro Zummo } 243edf1aaa3SAlessandro Zummo 244edf1aaa3SAlessandro Zummo i2c_set_clientdata(client, rtc); 245edf1aaa3SAlessandro Zummo 246*8a95b252SKumar Gala /* read control register */ 247*8a95b252SKumar Gala err = ds1672_get_control(client, &control); 248*8a95b252SKumar Gala if (err) { 249*8a95b252SKumar Gala dev_err(&client->dev, "%s: read error\n", __FUNCTION__); 250*8a95b252SKumar Gala goto exit_detach; 251*8a95b252SKumar Gala } 252*8a95b252SKumar Gala 253*8a95b252SKumar Gala if (control & DS1672_REG_CONTROL_EOSC) 254*8a95b252SKumar Gala dev_warn(&client->dev, "Oscillator not enabled. " 255*8a95b252SKumar Gala "Set time to enable.\n"); 256*8a95b252SKumar Gala 257*8a95b252SKumar Gala /* Register sysfs hooks */ 258*8a95b252SKumar Gala device_create_file(&client->dev, &dev_attr_control); 259*8a95b252SKumar Gala 260edf1aaa3SAlessandro Zummo return 0; 261edf1aaa3SAlessandro Zummo 262edf1aaa3SAlessandro Zummo exit_detach: 263edf1aaa3SAlessandro Zummo i2c_detach_client(client); 264edf1aaa3SAlessandro Zummo 265edf1aaa3SAlessandro Zummo exit_kfree: 266edf1aaa3SAlessandro Zummo kfree(client); 267edf1aaa3SAlessandro Zummo 268edf1aaa3SAlessandro Zummo exit: 269edf1aaa3SAlessandro Zummo return err; 270edf1aaa3SAlessandro Zummo } 271edf1aaa3SAlessandro Zummo 272edf1aaa3SAlessandro Zummo static int __init ds1672_init(void) 273edf1aaa3SAlessandro Zummo { 274edf1aaa3SAlessandro Zummo return i2c_add_driver(&ds1672_driver); 275edf1aaa3SAlessandro Zummo } 276edf1aaa3SAlessandro Zummo 277edf1aaa3SAlessandro Zummo static void __exit ds1672_exit(void) 278edf1aaa3SAlessandro Zummo { 279edf1aaa3SAlessandro Zummo i2c_del_driver(&ds1672_driver); 280edf1aaa3SAlessandro Zummo } 281edf1aaa3SAlessandro Zummo 282edf1aaa3SAlessandro Zummo MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 283edf1aaa3SAlessandro Zummo MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver"); 284edf1aaa3SAlessandro Zummo MODULE_LICENSE("GPL"); 285edf1aaa3SAlessandro Zummo MODULE_VERSION(DRV_VERSION); 286edf1aaa3SAlessandro Zummo 287edf1aaa3SAlessandro Zummo module_init(ds1672_init); 288edf1aaa3SAlessandro Zummo module_exit(ds1672_exit); 289