1edf1aaa3SAlessandro Zummo /* 2edf1aaa3SAlessandro Zummo * An rtc/i2c driver for the Dallas DS1672 33903586aSAlessandro Zummo * Copyright 2005-06 Tower Technologies 43903586aSAlessandro Zummo * 53903586aSAlessandro Zummo * Author: Alessandro Zummo <a.zummo@towertech.it> 6edf1aaa3SAlessandro Zummo * 7edf1aaa3SAlessandro Zummo * This program is free software; you can redistribute it and/or modify 8edf1aaa3SAlessandro Zummo * it under the terms of the GNU General Public License version 2 as 9edf1aaa3SAlessandro Zummo * published by the Free Software Foundation. 10edf1aaa3SAlessandro Zummo */ 11edf1aaa3SAlessandro Zummo 12edf1aaa3SAlessandro Zummo #include <linux/i2c.h> 13edf1aaa3SAlessandro Zummo #include <linux/rtc.h> 14*2113852bSPaul Gortmaker #include <linux/module.h> 15edf1aaa3SAlessandro Zummo 161716b0feSAlessandro Zummo #define DRV_VERSION "0.4" 17edf1aaa3SAlessandro Zummo 18edf1aaa3SAlessandro Zummo /* Registers */ 19edf1aaa3SAlessandro Zummo 20edf1aaa3SAlessandro Zummo #define DS1672_REG_CNT_BASE 0 21edf1aaa3SAlessandro Zummo #define DS1672_REG_CONTROL 4 22edf1aaa3SAlessandro Zummo #define DS1672_REG_TRICKLE 5 23edf1aaa3SAlessandro Zummo 243903586aSAlessandro Zummo #define DS1672_REG_CONTROL_EOSC 0x80 25edf1aaa3SAlessandro Zummo 261716b0feSAlessandro Zummo static struct i2c_driver ds1672_driver; 27edf1aaa3SAlessandro Zummo 28edf1aaa3SAlessandro Zummo /* 29edf1aaa3SAlessandro Zummo * In the routines that deal directly with the ds1672 hardware, we use 30edf1aaa3SAlessandro Zummo * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch 31edf1aaa3SAlessandro Zummo * Epoch is initialized as 2000. Time is set to UTC. 32edf1aaa3SAlessandro Zummo */ 33edf1aaa3SAlessandro Zummo static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm) 34edf1aaa3SAlessandro Zummo { 35edf1aaa3SAlessandro Zummo unsigned long time; 36edf1aaa3SAlessandro Zummo unsigned char addr = DS1672_REG_CNT_BASE; 37edf1aaa3SAlessandro Zummo unsigned char buf[4]; 38edf1aaa3SAlessandro Zummo 39edf1aaa3SAlessandro Zummo struct i2c_msg msgs[] = { 40edf1aaa3SAlessandro Zummo {client->addr, 0, 1, &addr}, /* setup read ptr */ 41edf1aaa3SAlessandro Zummo {client->addr, I2C_M_RD, 4, buf}, /* read date */ 42edf1aaa3SAlessandro Zummo }; 43edf1aaa3SAlessandro Zummo 44edf1aaa3SAlessandro Zummo /* read date registers */ 45edf1aaa3SAlessandro Zummo if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 462a4e2b87SHarvey Harrison dev_err(&client->dev, "%s: read error\n", __func__); 47edf1aaa3SAlessandro Zummo return -EIO; 48edf1aaa3SAlessandro Zummo } 49edf1aaa3SAlessandro Zummo 50edf1aaa3SAlessandro Zummo dev_dbg(&client->dev, 5111966adcSJeff Garzik "%s: raw read data - counters=%02x,%02x,%02x,%02x\n", 522a4e2b87SHarvey Harrison __func__, buf[0], buf[1], buf[2], buf[3]); 53edf1aaa3SAlessandro Zummo 54edf1aaa3SAlessandro Zummo time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; 55edf1aaa3SAlessandro Zummo 56edf1aaa3SAlessandro Zummo rtc_time_to_tm(time, tm); 57edf1aaa3SAlessandro Zummo 58edf1aaa3SAlessandro Zummo dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 59edf1aaa3SAlessandro Zummo "mday=%d, mon=%d, year=%d, wday=%d\n", 602a4e2b87SHarvey Harrison __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, 61edf1aaa3SAlessandro Zummo tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 62edf1aaa3SAlessandro Zummo 63edf1aaa3SAlessandro Zummo return 0; 64edf1aaa3SAlessandro Zummo } 65edf1aaa3SAlessandro Zummo 66edf1aaa3SAlessandro Zummo static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs) 67edf1aaa3SAlessandro Zummo { 68edf1aaa3SAlessandro Zummo int xfer; 698a95b252SKumar Gala unsigned char buf[6]; 70edf1aaa3SAlessandro Zummo 71edf1aaa3SAlessandro Zummo buf[0] = DS1672_REG_CNT_BASE; 72edf1aaa3SAlessandro Zummo buf[1] = secs & 0x000000FF; 73edf1aaa3SAlessandro Zummo buf[2] = (secs & 0x0000FF00) >> 8; 74edf1aaa3SAlessandro Zummo buf[3] = (secs & 0x00FF0000) >> 16; 75edf1aaa3SAlessandro Zummo buf[4] = (secs & 0xFF000000) >> 24; 768a95b252SKumar Gala buf[5] = 0; /* set control reg to enable counting */ 77edf1aaa3SAlessandro Zummo 788a95b252SKumar Gala xfer = i2c_master_send(client, buf, 6); 798a95b252SKumar Gala if (xfer != 6) { 802a4e2b87SHarvey Harrison dev_err(&client->dev, "%s: send: %d\n", __func__, xfer); 81edf1aaa3SAlessandro Zummo return -EIO; 82edf1aaa3SAlessandro Zummo } 83edf1aaa3SAlessandro Zummo 84edf1aaa3SAlessandro Zummo return 0; 85edf1aaa3SAlessandro Zummo } 86edf1aaa3SAlessandro Zummo 87edf1aaa3SAlessandro Zummo static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm) 88edf1aaa3SAlessandro Zummo { 89edf1aaa3SAlessandro Zummo return ds1672_get_datetime(to_i2c_client(dev), tm); 90edf1aaa3SAlessandro Zummo } 91edf1aaa3SAlessandro Zummo 92edf1aaa3SAlessandro Zummo static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs) 93edf1aaa3SAlessandro Zummo { 94edf1aaa3SAlessandro Zummo return ds1672_set_mmss(to_i2c_client(dev), secs); 95edf1aaa3SAlessandro Zummo } 96edf1aaa3SAlessandro Zummo 978a95b252SKumar Gala static int ds1672_get_control(struct i2c_client *client, u8 *status) 988a95b252SKumar Gala { 998a95b252SKumar Gala unsigned char addr = DS1672_REG_CONTROL; 1008a95b252SKumar Gala 1018a95b252SKumar Gala struct i2c_msg msgs[] = { 1028a95b252SKumar Gala {client->addr, 0, 1, &addr}, /* setup read ptr */ 1038a95b252SKumar Gala {client->addr, I2C_M_RD, 1, status}, /* read control */ 1048a95b252SKumar Gala }; 1058a95b252SKumar Gala 1068a95b252SKumar Gala /* read control register */ 1078a95b252SKumar Gala if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 1082a4e2b87SHarvey Harrison dev_err(&client->dev, "%s: read error\n", __func__); 1098a95b252SKumar Gala return -EIO; 1108a95b252SKumar Gala } 1118a95b252SKumar Gala 1128a95b252SKumar Gala return 0; 1138a95b252SKumar Gala } 1148a95b252SKumar Gala 1158a95b252SKumar Gala /* following are the sysfs callback functions */ 1161716b0feSAlessandro Zummo static ssize_t show_control(struct device *dev, struct device_attribute *attr, 1171716b0feSAlessandro Zummo char *buf) 1188a95b252SKumar Gala { 1198a95b252SKumar Gala struct i2c_client *client = to_i2c_client(dev); 1208a95b252SKumar Gala u8 control; 1218a95b252SKumar Gala int err; 1228a95b252SKumar Gala 1238a95b252SKumar Gala err = ds1672_get_control(client, &control); 1248a95b252SKumar Gala if (err) 1258a95b252SKumar Gala return err; 1268a95b252SKumar Gala 1273903586aSAlessandro Zummo return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC) 1283903586aSAlessandro Zummo ? "disabled" : "enabled"); 1298a95b252SKumar Gala } 1301716b0feSAlessandro Zummo 1318a95b252SKumar Gala static DEVICE_ATTR(control, S_IRUGO, show_control, NULL); 1328a95b252SKumar Gala 133ff8371acSDavid Brownell static const struct rtc_class_ops ds1672_rtc_ops = { 134edf1aaa3SAlessandro Zummo .read_time = ds1672_rtc_read_time, 135edf1aaa3SAlessandro Zummo .set_mmss = ds1672_rtc_set_mmss, 136edf1aaa3SAlessandro Zummo }; 137edf1aaa3SAlessandro Zummo 1381716b0feSAlessandro Zummo static int ds1672_remove(struct i2c_client *client) 139edf1aaa3SAlessandro Zummo { 140edf1aaa3SAlessandro Zummo struct rtc_device *rtc = i2c_get_clientdata(client); 141edf1aaa3SAlessandro Zummo 142edf1aaa3SAlessandro Zummo if (rtc) 143edf1aaa3SAlessandro Zummo rtc_device_unregister(rtc); 144edf1aaa3SAlessandro Zummo 145edf1aaa3SAlessandro Zummo return 0; 146edf1aaa3SAlessandro Zummo } 147edf1aaa3SAlessandro Zummo 1481716b0feSAlessandro Zummo static int ds1672_probe(struct i2c_client *client, 1491716b0feSAlessandro Zummo const struct i2c_device_id *id) 150edf1aaa3SAlessandro Zummo { 151edf1aaa3SAlessandro Zummo int err = 0; 1528a95b252SKumar Gala u8 control; 153edf1aaa3SAlessandro Zummo struct rtc_device *rtc; 154edf1aaa3SAlessandro Zummo 1551716b0feSAlessandro Zummo dev_dbg(&client->dev, "%s\n", __func__); 156edf1aaa3SAlessandro Zummo 1571716b0feSAlessandro Zummo if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 1581716b0feSAlessandro Zummo return -ENODEV; 159edf1aaa3SAlessandro Zummo 160edf1aaa3SAlessandro Zummo dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 161edf1aaa3SAlessandro Zummo 162edf1aaa3SAlessandro Zummo rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev, 163edf1aaa3SAlessandro Zummo &ds1672_rtc_ops, THIS_MODULE); 164edf1aaa3SAlessandro Zummo 1651716b0feSAlessandro Zummo if (IS_ERR(rtc)) 1661716b0feSAlessandro Zummo return PTR_ERR(rtc); 167edf1aaa3SAlessandro Zummo 168edf1aaa3SAlessandro Zummo i2c_set_clientdata(client, rtc); 169edf1aaa3SAlessandro Zummo 1708a95b252SKumar Gala /* read control register */ 1718a95b252SKumar Gala err = ds1672_get_control(client, &control); 1723903586aSAlessandro Zummo if (err) 17391046a8aSJeff Garzik goto exit_devreg; 1748a95b252SKumar Gala 1758a95b252SKumar Gala if (control & DS1672_REG_CONTROL_EOSC) 1768a95b252SKumar Gala dev_warn(&client->dev, "Oscillator not enabled. " 1778a95b252SKumar Gala "Set time to enable.\n"); 1788a95b252SKumar Gala 1798a95b252SKumar Gala /* Register sysfs hooks */ 18091046a8aSJeff Garzik err = device_create_file(&client->dev, &dev_attr_control); 18191046a8aSJeff Garzik if (err) 18291046a8aSJeff Garzik goto exit_devreg; 1838a95b252SKumar Gala 184edf1aaa3SAlessandro Zummo return 0; 185edf1aaa3SAlessandro Zummo 18691046a8aSJeff Garzik exit_devreg: 18791046a8aSJeff Garzik rtc_device_unregister(rtc); 188edf1aaa3SAlessandro Zummo return err; 189edf1aaa3SAlessandro Zummo } 190edf1aaa3SAlessandro Zummo 191fe102c71SAlessandro Zummo static struct i2c_device_id ds1672_id[] = { 192fe102c71SAlessandro Zummo { "ds1672", 0 }, 193fe102c71SAlessandro Zummo { } 194fe102c71SAlessandro Zummo }; 195fe102c71SAlessandro Zummo 1961716b0feSAlessandro Zummo static struct i2c_driver ds1672_driver = { 1971716b0feSAlessandro Zummo .driver = { 1981716b0feSAlessandro Zummo .name = "rtc-ds1672", 1991716b0feSAlessandro Zummo }, 2001716b0feSAlessandro Zummo .probe = &ds1672_probe, 2011716b0feSAlessandro Zummo .remove = &ds1672_remove, 202fe102c71SAlessandro Zummo .id_table = ds1672_id, 2031716b0feSAlessandro Zummo }; 2041716b0feSAlessandro Zummo 205edf1aaa3SAlessandro Zummo static int __init ds1672_init(void) 206edf1aaa3SAlessandro Zummo { 207edf1aaa3SAlessandro Zummo return i2c_add_driver(&ds1672_driver); 208edf1aaa3SAlessandro Zummo } 209edf1aaa3SAlessandro Zummo 210edf1aaa3SAlessandro Zummo static void __exit ds1672_exit(void) 211edf1aaa3SAlessandro Zummo { 212edf1aaa3SAlessandro Zummo i2c_del_driver(&ds1672_driver); 213edf1aaa3SAlessandro Zummo } 214edf1aaa3SAlessandro Zummo 215edf1aaa3SAlessandro Zummo MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 216edf1aaa3SAlessandro Zummo MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver"); 217edf1aaa3SAlessandro Zummo MODULE_LICENSE("GPL"); 218edf1aaa3SAlessandro Zummo MODULE_VERSION(DRV_VERSION); 219edf1aaa3SAlessandro Zummo 220edf1aaa3SAlessandro Zummo module_init(ds1672_init); 221edf1aaa3SAlessandro Zummo module_exit(ds1672_exit); 222