/* * An I2C driver for the Epson RX8581 RTC * * Author: Martyn Welch <martyn.welch@ge.com> * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc. * * 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. * * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC) * Copyright 2005-06 Tower Technologies */ #include <linux/module.h> #include <linux/i2c.h> #include <linux/bcd.h> #include <linux/rtc.h> #include <linux/log2.h> #define DRV_VERSION "0.1" #define RX8581_REG_SC 0x00 /* Second in BCD */ #define RX8581_REG_MN 0x01 /* Minute in BCD */ #define RX8581_REG_HR 0x02 /* Hour in BCD */ #define RX8581_REG_DW 0x03 /* Day of Week */ #define RX8581_REG_DM 0x04 /* Day of Month in BCD */ #define RX8581_REG_MO 0x05 /* Month in BCD */ #define RX8581_REG_YR 0x06 /* Year in BCD */ #define RX8581_REG_RAM 0x07 /* RAM */ #define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/ #define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */ #define RX8581_REG_ADM 0x0A #define RX8581_REG_ADW 0x0A #define RX8581_REG_TMR0 0x0B #define RX8581_REG_TMR1 0x0C #define RX8581_REG_EXT 0x0D /* Extension Register */ #define RX8581_REG_FLAG 0x0E /* Flag Register */ #define RX8581_REG_CTRL 0x0F /* Control Register */ /* Flag Register bit definitions */ #define RX8581_FLAG_UF 0x20 /* Update */ #define RX8581_FLAG_TF 0x10 /* Timer */ #define RX8581_FLAG_AF 0x08 /* Alarm */ #define RX8581_FLAG_VLF 0x02 /* Voltage Low */ /* Control Register bit definitions */ #define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */ #define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */ #define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */ #define RX8581_CTRL_STOP 0x02 /* STOP bit */ #define RX8581_CTRL_RESET 0x01 /* RESET bit */ static struct i2c_driver rx8581_driver; /* * In the routines that deal directly with the rx8581 hardware, we use * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. */ static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm) { unsigned char date[7]; int data, err; /* First we ensure that the "update flag" is not set, we read the * time and date then re-read the "update flag". If the update flag * has been set, we know that the time has changed during the read so * we repeat the whole process again. */ data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); if (data < 0) { dev_err(&client->dev, "Unable to read device flags\n"); return -EIO; } do { /* If update flag set, clear it */ if (data & RX8581_FLAG_UF) { err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF)); if (err != 0) { dev_err(&client->dev, "Unable to write device " "flags\n"); return -EIO; } } /* Now read time and date */ err = i2c_smbus_read_i2c_block_data(client, RX8581_REG_SC, 7, date); if (err < 0) { dev_err(&client->dev, "Unable to read date\n"); return -EIO; } /* Check flag register */ data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); if (data < 0) { dev_err(&client->dev, "Unable to read device flags\n"); return -EIO; } } while (data & RX8581_FLAG_UF); if (data & RX8581_FLAG_VLF) dev_info(&client->dev, "low voltage detected, date/time is not reliable.\n"); dev_dbg(&client->dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, " "wday=%02x, mday=%02x, mon=%02x, year=%02x\n", __func__, date[0], date[1], date[2], date[3], date[4], date[5], date[6]); tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F); tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F); tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */ tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F); tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F); tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ tm->tm_year = bcd2bin(date[RX8581_REG_YR]); if (tm->tm_year < 70) tm->tm_year += 100; /* assume we are in 1970...2069 */ 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); err = rtc_valid_tm(tm); if (err < 0) dev_err(&client->dev, "retrieved date/time is not valid.\n"); return err; } static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm) { int data, err; unsigned char buf[7]; dev_dbg(&client->dev, "%s: 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); /* hours, minutes and seconds */ buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec); buf[RX8581_REG_MN] = bin2bcd(tm->tm_min); buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour); buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday); /* month, 1 - 12 */ buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1); /* year and century */ buf[RX8581_REG_YR] = bin2bcd(tm->tm_year % 100); buf[RX8581_REG_DW] = (0x1 << tm->tm_wday); /* Stop the clock */ data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL); if (data < 0) { dev_err(&client->dev, "Unable to read control register\n"); return -EIO; } err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL, (data | RX8581_CTRL_STOP)); if (err < 0) { dev_err(&client->dev, "Unable to write control register\n"); return -EIO; } /* write register's data */ err = i2c_smbus_write_i2c_block_data(client, RX8581_REG_SC, 7, buf); if (err < 0) { dev_err(&client->dev, "Unable to write to date registers\n"); return -EIO; } /* get VLF and clear it */ data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); if (data < 0) { dev_err(&client->dev, "Unable to read flag register\n"); return -EIO; } err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG, (data & ~(RX8581_FLAG_VLF))); if (err != 0) { dev_err(&client->dev, "Unable to write flag register\n"); return -EIO; } /* Restart the clock */ data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL); if (data < 0) { dev_err(&client->dev, "Unable to read control register\n"); return -EIO; } err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL, (data & ~(RX8581_CTRL_STOP))); if (err != 0) { dev_err(&client->dev, "Unable to write control register\n"); return -EIO; } return 0; } static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm) { return rx8581_get_datetime(to_i2c_client(dev), tm); } static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm) { return rx8581_set_datetime(to_i2c_client(dev), tm); } static const struct rtc_class_ops rx8581_rtc_ops = { .read_time = rx8581_rtc_read_time, .set_time = rx8581_rtc_set_time, }; static int __devinit rx8581_probe(struct i2c_client *client, const struct i2c_device_id *id) { 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(rx8581_driver.driver.name, &client->dev, &rx8581_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); i2c_set_clientdata(client, rtc); return 0; } static int __devexit rx8581_remove(struct i2c_client *client) { struct rtc_device *rtc = i2c_get_clientdata(client); rtc_device_unregister(rtc); return 0; } static const struct i2c_device_id rx8581_id[] = { { "rx8581", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, rx8581_id); static struct i2c_driver rx8581_driver = { .driver = { .name = "rtc-rx8581", .owner = THIS_MODULE, }, .probe = rx8581_probe, .remove = __devexit_p(rx8581_remove), .id_table = rx8581_id, }; module_i2c_driver(rx8581_driver); MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>"); MODULE_DESCRIPTION("Epson RX-8581 RTC driver"); MODULE_LICENSE("GPL"); MODULE_VERSION(DRV_VERSION);