/* * An rtc/i2c driver for the Dallas DS1672 * Copyright 2005-06 Tower Technologies * * Author: Alessandro Zummo <a.zummo@towertech.it> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/i2c.h> #include <linux/rtc.h> #include <linux/module.h> #define DRV_VERSION "0.4" /* Registers */ #define DS1672_REG_CNT_BASE 0 #define DS1672_REG_CONTROL 4 #define DS1672_REG_TRICKLE 5 #define DS1672_REG_CONTROL_EOSC 0x80 static struct i2c_driver ds1672_driver; /* * In the routines that deal directly with the ds1672 hardware, we use * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch * Epoch is initialized as 2000. Time is set to UTC. */ static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm) { unsigned long time; unsigned char addr = DS1672_REG_CNT_BASE; unsigned char buf[4]; struct i2c_msg msgs[] = { {client->addr, 0, 1, &addr}, /* setup read ptr */ {client->addr, I2C_M_RD, 4, buf}, /* read date */ }; /* read date registers */ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { dev_err(&client->dev, "%s: read error\n", __func__); return -EIO; } dev_dbg(&client->dev, "%s: raw read data - counters=%02x,%02x,%02x,%02x\n", __func__, buf[0], buf[1], buf[2], buf[3]); time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; rtc_time_to_tm(time, tm); dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " "mday=%d, mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); return 0; } static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs) { int xfer; unsigned char buf[6]; buf[0] = DS1672_REG_CNT_BASE; buf[1] = secs & 0x000000FF; buf[2] = (secs & 0x0000FF00) >> 8; buf[3] = (secs & 0x00FF0000) >> 16; buf[4] = (secs & 0xFF000000) >> 24; buf[5] = 0; /* set control reg to enable counting */ xfer = i2c_master_send(client, buf, 6); if (xfer != 6) { dev_err(&client->dev, "%s: send: %d\n", __func__, xfer); return -EIO; } return 0; } static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm) { return ds1672_get_datetime(to_i2c_client(dev), tm); } static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs) { return ds1672_set_mmss(to_i2c_client(dev), secs); } static int ds1672_get_control(struct i2c_client *client, u8 *status) { unsigned char addr = DS1672_REG_CONTROL; struct i2c_msg msgs[] = { {client->addr, 0, 1, &addr}, /* setup read ptr */ {client->addr, I2C_M_RD, 1, status}, /* read control */ }; /* read control register */ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { dev_err(&client->dev, "%s: read error\n", __func__); return -EIO; } return 0; } /* following are the sysfs callback functions */ static ssize_t show_control(struct device *dev, struct device_attribute *attr, char *buf) { struct i2c_client *client = to_i2c_client(dev); u8 control; int err; err = ds1672_get_control(client, &control); if (err) return err; return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC) ? "disabled" : "enabled"); } static DEVICE_ATTR(control, S_IRUGO, show_control, NULL); static const struct rtc_class_ops ds1672_rtc_ops = { .read_time = ds1672_rtc_read_time, .set_mmss = ds1672_rtc_set_mmss, }; static int ds1672_remove(struct i2c_client *client) { struct rtc_device *rtc = i2c_get_clientdata(client); if (rtc) rtc_device_unregister(rtc); return 0; } static int ds1672_probe(struct i2c_client *client, const struct i2c_device_id *id) { int err = 0; u8 control; struct rtc_device *rtc; dev_dbg(&client->dev, "%s\n", __func__); if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) return -ENODEV; dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev, &ds1672_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); i2c_set_clientdata(client, rtc); /* read control register */ err = ds1672_get_control(client, &control); if (err) goto exit_devreg; if (control & DS1672_REG_CONTROL_EOSC) dev_warn(&client->dev, "Oscillator not enabled. " "Set time to enable.\n"); /* Register sysfs hooks */ err = device_create_file(&client->dev, &dev_attr_control); if (err) goto exit_devreg; return 0; exit_devreg: rtc_device_unregister(rtc); return err; } static struct i2c_device_id ds1672_id[] = { { "ds1672", 0 }, { } }; static struct i2c_driver ds1672_driver = { .driver = { .name = "rtc-ds1672", }, .probe = &ds1672_probe, .remove = &ds1672_remove, .id_table = ds1672_id, }; static int __init ds1672_init(void) { return i2c_add_driver(&ds1672_driver); } static void __exit ds1672_exit(void) { i2c_del_driver(&ds1672_driver); } MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver"); MODULE_LICENSE("GPL"); MODULE_VERSION(DRV_VERSION); module_init(ds1672_init); module_exit(ds1672_exit);