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Diffstat (limited to '')
| -rw-r--r-- | drivers/rtc/rtc-ds1347.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds1347.c b/drivers/rtc/rtc-ds1347.c new file mode 100644 index 000000000..938512c67 --- /dev/null +++ b/drivers/rtc/rtc-ds1347.c @@ -0,0 +1,175 @@ +/* rtc-ds1347.c + * + * Driver for Dallas Semiconductor DS1347 Low Current, SPI Compatible + * Real Time Clock + * + * Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com> + * + * 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. + * + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> +#include <linux/spi/spi.h> +#include <linux/bcd.h> +#include <linux/regmap.h> + +/* Registers in ds1347 rtc */ + +#define DS1347_SECONDS_REG 0x01 +#define DS1347_MINUTES_REG 0x03 +#define DS1347_HOURS_REG 0x05 +#define DS1347_DATE_REG 0x07 +#define DS1347_MONTH_REG 0x09 +#define DS1347_DAY_REG 0x0B +#define DS1347_YEAR_REG 0x0D +#define DS1347_CONTROL_REG 0x0F +#define DS1347_STATUS_REG 0x17 +#define DS1347_CLOCK_BURST 0x3F + +static const struct regmap_range ds1347_ranges[] = { + { + .range_min = DS1347_SECONDS_REG, + .range_max = DS1347_STATUS_REG, + }, +}; + +static const struct regmap_access_table ds1347_access_table = { + .yes_ranges = ds1347_ranges, + .n_yes_ranges = ARRAY_SIZE(ds1347_ranges), +}; + +static int ds1347_read_time(struct device *dev, struct rtc_time *dt) +{ + struct spi_device *spi = to_spi_device(dev); + struct regmap *map; + int err; + unsigned char buf[8]; + + map = spi_get_drvdata(spi); + + err = regmap_bulk_read(map, DS1347_CLOCK_BURST, buf, 8); + if (err) + return err; + + dt->tm_sec = bcd2bin(buf[0]); + dt->tm_min = bcd2bin(buf[1]); + dt->tm_hour = bcd2bin(buf[2] & 0x3F); + dt->tm_mday = bcd2bin(buf[3]); + dt->tm_mon = bcd2bin(buf[4]) - 1; + dt->tm_wday = bcd2bin(buf[5]) - 1; + dt->tm_year = bcd2bin(buf[6]) + 100; + + return 0; +} + +static int ds1347_set_time(struct device *dev, struct rtc_time *dt) +{ + struct spi_device *spi = to_spi_device(dev); + struct regmap *map; + unsigned char buf[8]; + + map = spi_get_drvdata(spi); + + buf[0] = bin2bcd(dt->tm_sec); + buf[1] = bin2bcd(dt->tm_min); + buf[2] = (bin2bcd(dt->tm_hour) & 0x3F); + buf[3] = bin2bcd(dt->tm_mday); + buf[4] = bin2bcd(dt->tm_mon + 1); + buf[5] = bin2bcd(dt->tm_wday + 1); + + /* year in linux is from 1900 i.e in range of 100 + in rtc it is from 00 to 99 */ + dt->tm_year = dt->tm_year % 100; + + buf[6] = bin2bcd(dt->tm_year); + buf[7] = bin2bcd(0x00); + + /* write the rtc settings */ + return regmap_bulk_write(map, DS1347_CLOCK_BURST, buf, 8); +} + +static const struct rtc_class_ops ds1347_rtc_ops = { + .read_time = ds1347_read_time, + .set_time = ds1347_set_time, +}; + +static int ds1347_probe(struct spi_device *spi) +{ + struct rtc_device *rtc; + struct regmap_config config; + struct regmap *map; + unsigned int data; + int res; + + memset(&config, 0, sizeof(config)); + config.reg_bits = 8; + config.val_bits = 8; + config.read_flag_mask = 0x80; + config.max_register = 0x3F; + config.wr_table = &ds1347_access_table; + + /* spi setup with ds1347 in mode 3 and bits per word as 8 */ + spi->mode = SPI_MODE_3; + spi->bits_per_word = 8; + spi_setup(spi); + + map = devm_regmap_init_spi(spi, &config); + + if (IS_ERR(map)) { + dev_err(&spi->dev, "ds1347 regmap init spi failed\n"); + return PTR_ERR(map); + } + + spi_set_drvdata(spi, map); + + /* RTC Settings */ + res = regmap_read(map, DS1347_SECONDS_REG, &data); + if (res) + return res; + + /* Disable the write protect of rtc */ + regmap_read(map, DS1347_CONTROL_REG, &data); + data = data & ~(1<<7); + regmap_write(map, DS1347_CONTROL_REG, data); + + /* Enable the oscillator , disable the oscillator stop flag, + and glitch filter to reduce current consumption */ + regmap_read(map, DS1347_STATUS_REG, &data); + data = data & 0x1B; + regmap_write(map, DS1347_STATUS_REG, data); + + /* display the settings */ + regmap_read(map, DS1347_CONTROL_REG, &data); + dev_info(&spi->dev, "DS1347 RTC CTRL Reg = 0x%02x\n", data); + + regmap_read(map, DS1347_STATUS_REG, &data); + dev_info(&spi->dev, "DS1347 RTC Status Reg = 0x%02x\n", data); + + rtc = devm_rtc_device_register(&spi->dev, "ds1347", + &ds1347_rtc_ops, THIS_MODULE); + + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + return 0; +} + +static struct spi_driver ds1347_driver = { + .driver = { + .name = "ds1347", + }, + .probe = ds1347_probe, +}; + +module_spi_driver(ds1347_driver); + +MODULE_DESCRIPTION("DS1347 SPI RTC DRIVER"); +MODULE_AUTHOR("Raghavendra C Ganiga <ravi23ganiga@gmail.com>"); +MODULE_LICENSE("GPL v2"); |