v4.19.13 snapshot.
diff --git a/drivers/rtc/rtc-ds1347.c b/drivers/rtc/rtc-ds1347.c
new file mode 100644
index 0000000..938512c
--- /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");