diff options
Diffstat (limited to 'drivers/rtc/rtc-ds1390.c')
| -rw-r--r-- | drivers/rtc/rtc-ds1390.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds1390.c b/drivers/rtc/rtc-ds1390.c new file mode 100644 index 0000000..599e976 --- /dev/null +++ b/drivers/rtc/rtc-ds1390.c @@ -0,0 +1,220 @@ +/* + * rtc-ds1390.c -- driver for DS1390/93/94 + * + * Copyright (C) 2008 Mercury IMC Ltd + * Written by Mark Jackson <mpfj@mimc.co.uk> + * + * 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. + * + * NOTE : Currently this driver only supports the bare minimum for read + * and write the RTC. The extra features provided by the chip family + * (alarms, trickle charger, different control registers) are unavailable. + */ + +#include <linux/platform_device.h> +#include <linux/rtc.h> +#include <linux/spi/spi.h> +#include <linux/bcd.h> + +#define DS1390_REG_100THS 0x00 +#define DS1390_REG_SECONDS 0x01 +#define DS1390_REG_MINUTES 0x02 +#define DS1390_REG_HOURS 0x03 +#define DS1390_REG_DAY 0x04 +#define DS1390_REG_DATE 0x05 +#define DS1390_REG_MONTH_CENT 0x06 +#define DS1390_REG_YEAR 0x07 + +#define DS1390_REG_ALARM_100THS 0x08 +#define DS1390_REG_ALARM_SECONDS 0x09 +#define DS1390_REG_ALARM_MINUTES 0x0A +#define DS1390_REG_ALARM_HOURS 0x0B +#define DS1390_REG_ALARM_DAY_DATE 0x0C + +#define DS1390_REG_CONTROL 0x0D +#define DS1390_REG_STATUS 0x0E +#define DS1390_REG_TRICKLE 0x0F + +struct ds1390 { + struct rtc_device *rtc; + u8 txrx_buf[9]; /* cmd + 8 registers */ +}; + +static void ds1390_set_reg(struct device *dev, unsigned char address, + unsigned char data) +{ + struct spi_device *spi = to_spi_device(dev); + struct ds1390 *chip = dev_get_drvdata(dev); + + /* Set MSB to indicate write */ + chip->txrx_buf[0] = address | 0x80; + chip->txrx_buf[1] = data; + + /* do the i/o */ + spi_write_then_read(spi, chip->txrx_buf, 2, NULL, 0); +} + +static int ds1390_get_reg(struct device *dev, unsigned char address, + unsigned char *data) +{ + struct spi_device *spi = to_spi_device(dev); + struct ds1390 *chip = dev_get_drvdata(dev); + int status; + + if (!data) + return -EINVAL; + + /* Clear MSB to indicate read */ + chip->txrx_buf[0] = address & 0x7f; + /* do the i/o */ + status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 1); + if (status != 0) + return status; + + *data = chip->txrx_buf[1]; + + return 0; +} + +static int ds1390_get_datetime(struct device *dev, struct rtc_time *dt) +{ + struct spi_device *spi = to_spi_device(dev); + struct ds1390 *chip = dev_get_drvdata(dev); + int status; + + /* build the message */ + chip->txrx_buf[0] = DS1390_REG_SECONDS; + + /* do the i/o */ + status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 8); + if (status != 0) + return status; + + /* The chip sends data in this order: + * Seconds, Minutes, Hours, Day, Date, Month / Century, Year */ + dt->tm_sec = bcd2bin(chip->txrx_buf[0]); + dt->tm_min = bcd2bin(chip->txrx_buf[1]); + dt->tm_hour = bcd2bin(chip->txrx_buf[2]); + dt->tm_wday = bcd2bin(chip->txrx_buf[3]); + dt->tm_mday = bcd2bin(chip->txrx_buf[4]); + /* mask off century bit */ + dt->tm_mon = bcd2bin(chip->txrx_buf[5] & 0x7f) - 1; + /* adjust for century bit */ + dt->tm_year = bcd2bin(chip->txrx_buf[6]) + ((chip->txrx_buf[5] & 0x80) ? 100 : 0); + + return rtc_valid_tm(dt); +} + +static int ds1390_set_datetime(struct device *dev, struct rtc_time *dt) +{ + struct spi_device *spi = to_spi_device(dev); + struct ds1390 *chip = dev_get_drvdata(dev); + + /* build the message */ + chip->txrx_buf[0] = DS1390_REG_SECONDS | 0x80; + chip->txrx_buf[1] = bin2bcd(dt->tm_sec); + chip->txrx_buf[2] = bin2bcd(dt->tm_min); + chip->txrx_buf[3] = bin2bcd(dt->tm_hour); + chip->txrx_buf[4] = bin2bcd(dt->tm_wday); + chip->txrx_buf[5] = bin2bcd(dt->tm_mday); + chip->txrx_buf[6] = bin2bcd(dt->tm_mon + 1) | + ((dt->tm_year > 99) ? 0x80 : 0x00); + chip->txrx_buf[7] = bin2bcd(dt->tm_year % 100); + + /* do the i/o */ + return spi_write_then_read(spi, chip->txrx_buf, 8, NULL, 0); +} + +static int ds1390_read_time(struct device *dev, struct rtc_time *tm) +{ + return ds1390_get_datetime(dev, tm); +} + +static int ds1390_set_time(struct device *dev, struct rtc_time *tm) +{ + return ds1390_set_datetime(dev, tm); +} + +static const struct rtc_class_ops ds1390_rtc_ops = { + .read_time = ds1390_read_time, + .set_time = ds1390_set_time, +}; + +static int __devinit ds1390_probe(struct spi_device *spi) +{ + struct rtc_device *rtc; + unsigned char tmp; + struct ds1390 *chip; + int res; + + printk(KERN_DEBUG "DS1390 SPI RTC driver\n"); + + rtc = rtc_device_register("ds1390", + &spi->dev, &ds1390_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) { + printk(KERN_ALERT "RTC : unable to register device\n"); + return PTR_ERR(rtc); + } + + spi->mode = SPI_MODE_3; + spi->bits_per_word = 8; + spi_setup(spi); + + chip = kzalloc(sizeof *chip, GFP_KERNEL); + if (!chip) { + printk(KERN_ALERT "RTC : unable to allocate device memory\n"); + rtc_device_unregister(rtc); + return -ENOMEM; + } + chip->rtc = rtc; + dev_set_drvdata(&spi->dev, chip); + + res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp); + if (res) { + printk(KERN_ALERT "RTC : unable to read device\n"); + rtc_device_unregister(rtc); + return res; + } + + return 0; +} + +static int __devexit ds1390_remove(struct spi_device *spi) +{ + struct ds1390 *chip = platform_get_drvdata(spi); + struct rtc_device *rtc = chip->rtc; + + if (rtc) + rtc_device_unregister(rtc); + + kfree(chip); + + return 0; +} + +static struct spi_driver ds1390_driver = { + .driver = { + .name = "rtc-ds1390", + .owner = THIS_MODULE, + }, + .probe = ds1390_probe, + .remove = __devexit_p(ds1390_remove), +}; + +static __init int ds1390_init(void) +{ + return spi_register_driver(&ds1390_driver); +} +module_init(ds1390_init); + +static __exit void ds1390_exit(void) +{ + spi_unregister_driver(&ds1390_driver); +} +module_exit(ds1390_exit); + +MODULE_DESCRIPTION("DS1390/93/94 SPI RTC driver"); +MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>"); +MODULE_LICENSE("GPL"); |
