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> 142113852bSPaul Gortmaker #include <linux/module.h> 15edf1aaa3SAlessandro Zummo 16edf1aaa3SAlessandro Zummo /* Registers */ 17edf1aaa3SAlessandro Zummo 18edf1aaa3SAlessandro Zummo #define DS1672_REG_CNT_BASE 0 19edf1aaa3SAlessandro Zummo #define DS1672_REG_CONTROL 4 20edf1aaa3SAlessandro Zummo #define DS1672_REG_TRICKLE 5 21edf1aaa3SAlessandro Zummo 223903586aSAlessandro Zummo #define DS1672_REG_CONTROL_EOSC 0x80 23edf1aaa3SAlessandro Zummo 241716b0feSAlessandro Zummo static struct i2c_driver ds1672_driver; 25edf1aaa3SAlessandro Zummo 26edf1aaa3SAlessandro Zummo /* 27edf1aaa3SAlessandro Zummo * In the routines that deal directly with the ds1672 hardware, we use 28edf1aaa3SAlessandro Zummo * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch 29edf1aaa3SAlessandro Zummo * Epoch is initialized as 2000. Time is set to UTC. 30edf1aaa3SAlessandro Zummo */ 31edf1aaa3SAlessandro Zummo static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm) 32edf1aaa3SAlessandro Zummo { 33edf1aaa3SAlessandro Zummo unsigned long time; 34edf1aaa3SAlessandro Zummo unsigned char addr = DS1672_REG_CNT_BASE; 35edf1aaa3SAlessandro Zummo unsigned char buf[4]; 36edf1aaa3SAlessandro Zummo 37edf1aaa3SAlessandro Zummo struct i2c_msg msgs[] = { 382bfc37dfSShubhrajyoti D {/* setup read ptr */ 392bfc37dfSShubhrajyoti D .addr = client->addr, 402bfc37dfSShubhrajyoti D .len = 1, 412bfc37dfSShubhrajyoti D .buf = &addr 422bfc37dfSShubhrajyoti D }, 432bfc37dfSShubhrajyoti D {/* read date */ 442bfc37dfSShubhrajyoti D .addr = client->addr, 452bfc37dfSShubhrajyoti D .flags = I2C_M_RD, 462bfc37dfSShubhrajyoti D .len = 4, 472bfc37dfSShubhrajyoti D .buf = buf 482bfc37dfSShubhrajyoti D }, 49edf1aaa3SAlessandro Zummo }; 50edf1aaa3SAlessandro Zummo 51edf1aaa3SAlessandro Zummo /* read date registers */ 52edf1aaa3SAlessandro Zummo if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 532a4e2b87SHarvey Harrison dev_err(&client->dev, "%s: read error\n", __func__); 54edf1aaa3SAlessandro Zummo return -EIO; 55edf1aaa3SAlessandro Zummo } 56edf1aaa3SAlessandro Zummo 57edf1aaa3SAlessandro Zummo dev_dbg(&client->dev, 5811966adcSJeff Garzik "%s: raw read data - counters=%02x,%02x,%02x,%02x\n", 592a4e2b87SHarvey Harrison __func__, buf[0], buf[1], buf[2], buf[3]); 60edf1aaa3SAlessandro Zummo 61edf1aaa3SAlessandro Zummo time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; 62edf1aaa3SAlessandro Zummo 63edf1aaa3SAlessandro Zummo rtc_time_to_tm(time, tm); 64edf1aaa3SAlessandro Zummo 65edf1aaa3SAlessandro Zummo dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 66edf1aaa3SAlessandro Zummo "mday=%d, mon=%d, year=%d, wday=%d\n", 672a4e2b87SHarvey Harrison __func__, 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; 768a95b252SKumar 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; 838a95b252SKumar Gala buf[5] = 0; /* set control reg to enable counting */ 84edf1aaa3SAlessandro Zummo 858a95b252SKumar Gala xfer = i2c_master_send(client, buf, 6); 868a95b252SKumar Gala if (xfer != 6) { 872a4e2b87SHarvey Harrison dev_err(&client->dev, "%s: send: %d\n", __func__, xfer); 88edf1aaa3SAlessandro Zummo return -EIO; 89edf1aaa3SAlessandro Zummo } 90edf1aaa3SAlessandro Zummo 91edf1aaa3SAlessandro Zummo return 0; 92edf1aaa3SAlessandro Zummo } 93edf1aaa3SAlessandro Zummo 94edf1aaa3SAlessandro Zummo static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm) 95edf1aaa3SAlessandro Zummo { 96edf1aaa3SAlessandro Zummo return ds1672_get_datetime(to_i2c_client(dev), tm); 97edf1aaa3SAlessandro Zummo } 98edf1aaa3SAlessandro Zummo 99edf1aaa3SAlessandro Zummo static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs) 100edf1aaa3SAlessandro Zummo { 101edf1aaa3SAlessandro Zummo return ds1672_set_mmss(to_i2c_client(dev), secs); 102edf1aaa3SAlessandro Zummo } 103edf1aaa3SAlessandro Zummo 1048a95b252SKumar Gala static int ds1672_get_control(struct i2c_client *client, u8 *status) 1058a95b252SKumar Gala { 1068a95b252SKumar Gala unsigned char addr = DS1672_REG_CONTROL; 1078a95b252SKumar Gala 1088a95b252SKumar Gala struct i2c_msg msgs[] = { 1092bfc37dfSShubhrajyoti D {/* setup read ptr */ 1102bfc37dfSShubhrajyoti D .addr = client->addr, 1112bfc37dfSShubhrajyoti D .len = 1, 1122bfc37dfSShubhrajyoti D .buf = &addr 1132bfc37dfSShubhrajyoti D }, 1142bfc37dfSShubhrajyoti D {/* read control */ 1152bfc37dfSShubhrajyoti D .addr = client->addr, 1162bfc37dfSShubhrajyoti D .flags = I2C_M_RD, 1172bfc37dfSShubhrajyoti D .len = 1, 1182bfc37dfSShubhrajyoti D .buf = status 1192bfc37dfSShubhrajyoti D }, 1208a95b252SKumar Gala }; 1218a95b252SKumar Gala 1228a95b252SKumar Gala /* read control register */ 1238a95b252SKumar Gala if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 1242a4e2b87SHarvey Harrison dev_err(&client->dev, "%s: read error\n", __func__); 1258a95b252SKumar Gala return -EIO; 1268a95b252SKumar Gala } 1278a95b252SKumar Gala 1288a95b252SKumar Gala return 0; 1298a95b252SKumar Gala } 1308a95b252SKumar Gala 1318a95b252SKumar Gala /* following are the sysfs callback functions */ 1321716b0feSAlessandro Zummo static ssize_t show_control(struct device *dev, struct device_attribute *attr, 1331716b0feSAlessandro Zummo char *buf) 1348a95b252SKumar Gala { 1358a95b252SKumar Gala struct i2c_client *client = to_i2c_client(dev); 1368a95b252SKumar Gala u8 control; 1378a95b252SKumar Gala int err; 1388a95b252SKumar Gala 1398a95b252SKumar Gala err = ds1672_get_control(client, &control); 1408a95b252SKumar Gala if (err) 1418a95b252SKumar Gala return err; 1428a95b252SKumar Gala 1433903586aSAlessandro Zummo return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC) 1443903586aSAlessandro Zummo ? "disabled" : "enabled"); 1458a95b252SKumar Gala } 1461716b0feSAlessandro Zummo 1478a95b252SKumar Gala static DEVICE_ATTR(control, S_IRUGO, show_control, NULL); 1488a95b252SKumar Gala 149ff8371acSDavid Brownell static const struct rtc_class_ops ds1672_rtc_ops = { 150edf1aaa3SAlessandro Zummo .read_time = ds1672_rtc_read_time, 151edf1aaa3SAlessandro Zummo .set_mmss = ds1672_rtc_set_mmss, 152edf1aaa3SAlessandro Zummo }; 153edf1aaa3SAlessandro Zummo 1541716b0feSAlessandro Zummo static int ds1672_probe(struct i2c_client *client, 1551716b0feSAlessandro Zummo const struct i2c_device_id *id) 156edf1aaa3SAlessandro Zummo { 157edf1aaa3SAlessandro Zummo int err = 0; 1588a95b252SKumar Gala u8 control; 159edf1aaa3SAlessandro Zummo struct rtc_device *rtc; 160edf1aaa3SAlessandro Zummo 1611716b0feSAlessandro Zummo dev_dbg(&client->dev, "%s\n", __func__); 162edf1aaa3SAlessandro Zummo 1631716b0feSAlessandro Zummo if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 1641716b0feSAlessandro Zummo return -ENODEV; 165edf1aaa3SAlessandro Zummo 166aac8703cSJingoo Han rtc = devm_rtc_device_register(&client->dev, ds1672_driver.driver.name, 167edf1aaa3SAlessandro Zummo &ds1672_rtc_ops, THIS_MODULE); 168edf1aaa3SAlessandro Zummo 1691716b0feSAlessandro Zummo if (IS_ERR(rtc)) 1701716b0feSAlessandro Zummo return PTR_ERR(rtc); 171edf1aaa3SAlessandro Zummo 172edf1aaa3SAlessandro Zummo i2c_set_clientdata(client, rtc); 173edf1aaa3SAlessandro Zummo 1748a95b252SKumar Gala /* read control register */ 1758a95b252SKumar Gala err = ds1672_get_control(client, &control); 1764071ea25SAlessandro Zummo if (err) { 1774071ea25SAlessandro Zummo dev_warn(&client->dev, "Unable to read the control register\n"); 1784071ea25SAlessandro Zummo } 1798a95b252SKumar Gala 1808a95b252SKumar Gala if (control & DS1672_REG_CONTROL_EOSC) 1818a95b252SKumar Gala dev_warn(&client->dev, "Oscillator not enabled. " 1828a95b252SKumar Gala "Set time to enable.\n"); 1838a95b252SKumar Gala 1848a95b252SKumar Gala /* Register sysfs hooks */ 18591046a8aSJeff Garzik err = device_create_file(&client->dev, &dev_attr_control); 18691046a8aSJeff Garzik if (err) 1874071ea25SAlessandro Zummo dev_err(&client->dev, "Unable to create sysfs entry: %s\n", 1884071ea25SAlessandro Zummo dev_attr_control.attr.name); 1898a95b252SKumar Gala 190edf1aaa3SAlessandro Zummo return 0; 191edf1aaa3SAlessandro Zummo } 192edf1aaa3SAlessandro Zummo 193fe102c71SAlessandro Zummo static struct i2c_device_id ds1672_id[] = { 194fe102c71SAlessandro Zummo { "ds1672", 0 }, 195fe102c71SAlessandro Zummo { } 196fe102c71SAlessandro Zummo }; 1978ad0f5b6SAxel Lin MODULE_DEVICE_TABLE(i2c, ds1672_id); 198fe102c71SAlessandro Zummo 199*23194ac0SJavier Martinez Canillas static const struct of_device_id ds1672_of_match[] = { 200*23194ac0SJavier Martinez Canillas { .compatible = "dallas,ds1672" }, 201*23194ac0SJavier Martinez Canillas { } 202*23194ac0SJavier Martinez Canillas }; 203*23194ac0SJavier Martinez Canillas MODULE_DEVICE_TABLE(of, ds1672_of_match); 204*23194ac0SJavier Martinez Canillas 2051716b0feSAlessandro Zummo static struct i2c_driver ds1672_driver = { 2061716b0feSAlessandro Zummo .driver = { 2071716b0feSAlessandro Zummo .name = "rtc-ds1672", 208*23194ac0SJavier Martinez Canillas .of_match_table = of_match_ptr(ds1672_of_match), 2091716b0feSAlessandro Zummo }, 2101716b0feSAlessandro Zummo .probe = &ds1672_probe, 211fe102c71SAlessandro Zummo .id_table = ds1672_id, 2121716b0feSAlessandro Zummo }; 2131716b0feSAlessandro Zummo 2140abc9201SAxel Lin module_i2c_driver(ds1672_driver); 215edf1aaa3SAlessandro Zummo 216edf1aaa3SAlessandro Zummo MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 217edf1aaa3SAlessandro Zummo MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver"); 218edf1aaa3SAlessandro Zummo MODULE_LICENSE("GPL"); 219