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Release 4.14 drivers/rtc/rtc-ds1347.c

Directory: drivers/rtc
/* 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 rtc_valid_tm(dt); }

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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); }

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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; }

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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");

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Directory: drivers/rtc
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