diff options
Diffstat (limited to 'drivers/rtc/rtc-rx8581.c')
| -rw-r--r-- | drivers/rtc/rtc-rx8581.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-rx8581.c b/drivers/rtc/rtc-rx8581.c new file mode 100644 index 0000000..c9522f3 --- /dev/null +++ b/drivers/rtc/rtc-rx8581.c @@ -0,0 +1,281 @@ +/* + * An I2C driver for the Epson RX8581 RTC + * + * Author: Martyn Welch <martyn.welch@gefanuc.com> + * Copyright 2008 GE Fanuc 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_FLAG, + (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; + } + + /* 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_FLAG, + (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, +}; + +static int __init rx8581_init(void) +{ + return i2c_add_driver(&rx8581_driver); +} + +static void __exit rx8581_exit(void) +{ + i2c_del_driver(&rx8581_driver); +} + +MODULE_AUTHOR("Martyn Welch <martyn.welch@gefanuc.com>"); +MODULE_DESCRIPTION("Epson RX-8581 RTC driver"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(DRV_VERSION); + +module_init(rx8581_init); +module_exit(rx8581_exit); |