| /* |
| * 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 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 = devm_rtc_device_register(&client->dev, rx8581_driver.driver.name, |
| &rx8581_rtc_ops, THIS_MODULE); |
| |
| if (IS_ERR(rtc)) |
| return PTR_ERR(rtc); |
| |
| i2c_set_clientdata(client, 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, |
| .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); |