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![Alexandre Belloni](/assets/img/avatar_default.png)
The DS1347 can handle years from 0 to 9999, add century register support. Link: https://lore.kernel.org/r/20191007134724.15505-10-alexandre.belloni@bootlin.com Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
183 lines
4.2 KiB
C
183 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* rtc-ds1347.c
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*
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* Driver for Dallas Semiconductor DS1347 Low Current, SPI Compatible
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* Real Time Clock
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*
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* Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/platform_device.h>
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#include <linux/rtc.h>
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#include <linux/spi/spi.h>
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#include <linux/bcd.h>
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#include <linux/regmap.h>
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/* Registers in ds1347 rtc */
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#define DS1347_SECONDS_REG 0x01
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#define DS1347_MINUTES_REG 0x03
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#define DS1347_HOURS_REG 0x05
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#define DS1347_DATE_REG 0x07
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#define DS1347_MONTH_REG 0x09
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#define DS1347_DAY_REG 0x0B
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#define DS1347_YEAR_REG 0x0D
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#define DS1347_CONTROL_REG 0x0F
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#define DS1347_CENTURY_REG 0x13
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#define DS1347_STATUS_REG 0x17
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#define DS1347_CLOCK_BURST 0x3F
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#define DS1347_WP_BIT BIT(7)
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#define DS1347_NEOSC_BIT BIT(7)
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#define DS1347_OSF_BIT BIT(2)
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static const struct regmap_range ds1347_ranges[] = {
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{
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.range_min = DS1347_SECONDS_REG,
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.range_max = DS1347_STATUS_REG,
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},
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};
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static const struct regmap_access_table ds1347_access_table = {
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.yes_ranges = ds1347_ranges,
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.n_yes_ranges = ARRAY_SIZE(ds1347_ranges),
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};
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static int ds1347_read_time(struct device *dev, struct rtc_time *dt)
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{
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struct regmap *map = dev_get_drvdata(dev);
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unsigned int status, century, secs;
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unsigned char buf[8];
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int err;
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err = regmap_read(map, DS1347_STATUS_REG, &status);
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if (err)
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return err;
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if (status & DS1347_OSF_BIT)
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return -EINVAL;
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do {
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err = regmap_bulk_read(map, DS1347_CLOCK_BURST, buf, 8);
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if (err)
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return err;
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err = regmap_read(map, DS1347_CENTURY_REG, ¢ury);
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if (err)
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return err;
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err = regmap_read(map, DS1347_SECONDS_REG, &secs);
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if (err)
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return err;
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} while (buf[0] != secs);
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dt->tm_sec = bcd2bin(buf[0]);
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dt->tm_min = bcd2bin(buf[1] & 0x7f);
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dt->tm_hour = bcd2bin(buf[2] & 0x3F);
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dt->tm_mday = bcd2bin(buf[3]);
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dt->tm_mon = bcd2bin(buf[4]) - 1;
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dt->tm_wday = bcd2bin(buf[5]) - 1;
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dt->tm_year = (bcd2bin(century) * 100) + bcd2bin(buf[6]) - 1900;
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return 0;
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}
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static int ds1347_set_time(struct device *dev, struct rtc_time *dt)
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{
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struct regmap *map = dev_get_drvdata(dev);
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unsigned int century;
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unsigned char buf[8];
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int err;
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err = regmap_update_bits(map, DS1347_STATUS_REG,
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DS1347_NEOSC_BIT, DS1347_NEOSC_BIT);
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if (err)
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return err;
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buf[0] = bin2bcd(dt->tm_sec);
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buf[1] = bin2bcd(dt->tm_min);
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buf[2] = (bin2bcd(dt->tm_hour) & 0x3F);
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buf[3] = bin2bcd(dt->tm_mday);
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buf[4] = bin2bcd(dt->tm_mon + 1);
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buf[5] = bin2bcd(dt->tm_wday + 1);
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buf[6] = bin2bcd(dt->tm_year % 100);
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buf[7] = bin2bcd(0x00);
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err = regmap_bulk_write(map, DS1347_CLOCK_BURST, buf, 8);
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if (err)
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return err;
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century = (dt->tm_year / 100) + 19;
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err = regmap_write(map, DS1347_CENTURY_REG, century);
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if (err)
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return err;
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return regmap_update_bits(map, DS1347_STATUS_REG,
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DS1347_NEOSC_BIT | DS1347_OSF_BIT, 0);
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}
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static const struct rtc_class_ops ds1347_rtc_ops = {
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.read_time = ds1347_read_time,
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.set_time = ds1347_set_time,
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};
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static int ds1347_probe(struct spi_device *spi)
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{
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struct rtc_device *rtc;
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struct regmap_config config;
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struct regmap *map;
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int err;
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memset(&config, 0, sizeof(config));
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config.reg_bits = 8;
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config.val_bits = 8;
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config.read_flag_mask = 0x80;
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config.max_register = 0x3F;
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config.wr_table = &ds1347_access_table;
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/* spi setup with ds1347 in mode 3 and bits per word as 8 */
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spi->mode = SPI_MODE_3;
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spi->bits_per_word = 8;
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spi_setup(spi);
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map = devm_regmap_init_spi(spi, &config);
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if (IS_ERR(map)) {
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dev_err(&spi->dev, "ds1347 regmap init spi failed\n");
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return PTR_ERR(map);
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}
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spi_set_drvdata(spi, map);
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/* Disable the write protect of rtc */
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err = regmap_update_bits(map, DS1347_CONTROL_REG, DS1347_WP_BIT, 0);
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if (err)
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return err;
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rtc = devm_rtc_allocate_device(&spi->dev);
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if (IS_ERR(rtc))
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return PTR_ERR(rtc);
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rtc->ops = &ds1347_rtc_ops;
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rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
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rtc->range_max = RTC_TIMESTAMP_END_9999;
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return rtc_register_device(rtc);
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}
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static struct spi_driver ds1347_driver = {
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.driver = {
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.name = "ds1347",
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},
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.probe = ds1347_probe,
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};
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module_spi_driver(ds1347_driver);
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MODULE_DESCRIPTION("DS1347 SPI RTC DRIVER");
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MODULE_AUTHOR("Raghavendra C Ganiga <ravi23ganiga@gmail.com>");
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MODULE_LICENSE("GPL v2");
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