diff options
Diffstat (limited to 'drivers/rtc/rtc-rx8581.c')
| -rw-r--r-- | drivers/rtc/rtc-rx8581.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-rx8581.c b/drivers/rtc/rtc-rx8581.c new file mode 100644 index 000000000..eac882169 --- /dev/null +++ b/drivers/rtc/rtc-rx8581.c @@ -0,0 +1,244 @@ +/* + * 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/regmap.h> +#include <linux/rtc.h> +#include <linux/log2.h> + +#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 */ + +struct rx8581 { + struct regmap *regmap; + struct rtc_device *rtc; +}; + +/* + * 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_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct i2c_client *client = to_i2c_client(dev); + unsigned char date[7]; + unsigned int data; + int err; + struct rx8581 *rx8581 = i2c_get_clientdata(client); + + /* 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. + */ + err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data); + if (err < 0) + return err; + + if (data & RX8581_FLAG_VLF) { + dev_warn(dev, + "low voltage detected, date/time is not reliable.\n"); + return -EINVAL; + } + + do { + /* If update flag set, clear it */ + if (data & RX8581_FLAG_UF) { + err = regmap_write(rx8581->regmap, RX8581_REG_FLAG, + data & ~RX8581_FLAG_UF); + if (err < 0) + return err; + } + + /* Now read time and date */ + err = regmap_bulk_read(rx8581->regmap, RX8581_REG_SC, date, + sizeof(date)); + if (err < 0) + return err; + + /* Check flag register */ + err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data); + if (err < 0) + return err; + } while (data & RX8581_FLAG_UF); + + dev_dbg(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]) + 100; + + dev_dbg(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 rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct i2c_client *client = to_i2c_client(dev); + int err; + unsigned char buf[7]; + struct rx8581 *rx8581 = i2c_get_clientdata(client); + + dev_dbg(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 */ + err = regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL, + RX8581_CTRL_STOP, RX8581_CTRL_STOP); + if (err < 0) + return err; + + /* write register's data */ + err = regmap_bulk_write(rx8581->regmap, RX8581_REG_SC, + buf, sizeof(buf)); + if (err < 0) + return err; + + /* get VLF and clear it */ + err = regmap_update_bits(rx8581->regmap, RX8581_REG_FLAG, + RX8581_FLAG_VLF, 0); + if (err < 0) + return err; + + /* Restart the clock */ + return regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL, + RX8581_CTRL_STOP, 0); +} + +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 rx8581 *rx8581; + static const struct regmap_config config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = 0xf, + }; + + dev_dbg(&client->dev, "%s\n", __func__); + + rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL); + if (!rx8581) + return -ENOMEM; + + i2c_set_clientdata(client, rx8581); + + rx8581->regmap = devm_regmap_init_i2c(client, &config); + if (IS_ERR(rx8581->regmap)) + return PTR_ERR(rx8581->regmap); + + rx8581->rtc = devm_rtc_allocate_device(&client->dev); + if (IS_ERR(rx8581->rtc)) + return PTR_ERR(rx8581->rtc); + + rx8581->rtc->ops = &rx8581_rtc_ops; + rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; + rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099; + rx8581->rtc->start_secs = 0; + rx8581->rtc->set_start_time = true; + + return rtc_register_device(rx8581->rtc); +} + +static const struct i2c_device_id rx8581_id[] = { + { "rx8581", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, rx8581_id); + +static const struct of_device_id rx8581_of_match[] = { + { .compatible = "epson,rx8581" }, + { } +}; +MODULE_DEVICE_TABLE(of, rx8581_of_match); + +static struct i2c_driver rx8581_driver = { + .driver = { + .name = "rtc-rx8581", + .of_match_table = of_match_ptr(rx8581_of_match), + }, + .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"); |