v4.19.13 snapshot.
diff --git a/drivers/rtc/rtc-ds1672.c b/drivers/rtc/rtc-ds1672.c
new file mode 100644
index 0000000..9caaccc
--- /dev/null
+++ b/drivers/rtc/rtc-ds1672.c
@@ -0,0 +1,218 @@
+/*
+ * An rtc/i2c driver for the Dallas DS1672
+ * Copyright 2005-06 Tower Technologies
+ *
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * 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/i2c.h>
+#include <linux/rtc.h>
+#include <linux/module.h>
+
+/* Registers */
+
+#define DS1672_REG_CNT_BASE 0
+#define DS1672_REG_CONTROL 4
+#define DS1672_REG_TRICKLE 5
+
+#define DS1672_REG_CONTROL_EOSC 0x80
+
+static struct i2c_driver ds1672_driver;
+
+/*
+ * In the routines that deal directly with the ds1672 hardware, we use
+ * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
+ * Epoch is initialized as 2000. Time is set to UTC.
+ */
+static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ unsigned long time;
+ unsigned char addr = DS1672_REG_CNT_BASE;
+ unsigned char buf[4];
+
+ struct i2c_msg msgs[] = {
+ {/* setup read ptr */
+ .addr = client->addr,
+ .len = 1,
+ .buf = &addr
+ },
+ {/* read date */
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 4,
+ .buf = buf
+ },
+ };
+
+ /* read date registers */
+ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ return -EIO;
+ }
+
+ dev_dbg(&client->dev,
+ "%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
+ __func__, buf[0], buf[1], buf[2], buf[3]);
+
+ time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+
+ rtc_time_to_tm(time, tm);
+
+ dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
+ "mday=%d, mon=%d, year=%d, wday=%d\n",
+ __func__, tm->tm_sec, tm->tm_min, tm->tm_hour,
+ tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+ return 0;
+}
+
+static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
+{
+ int xfer;
+ unsigned char buf[6];
+
+ buf[0] = DS1672_REG_CNT_BASE;
+ buf[1] = secs & 0x000000FF;
+ buf[2] = (secs & 0x0000FF00) >> 8;
+ buf[3] = (secs & 0x00FF0000) >> 16;
+ buf[4] = (secs & 0xFF000000) >> 24;
+ buf[5] = 0; /* set control reg to enable counting */
+
+ xfer = i2c_master_send(client, buf, 6);
+ if (xfer != 6) {
+ dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return ds1672_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
+{
+ return ds1672_set_mmss(to_i2c_client(dev), secs);
+}
+
+static int ds1672_get_control(struct i2c_client *client, u8 *status)
+{
+ unsigned char addr = DS1672_REG_CONTROL;
+
+ struct i2c_msg msgs[] = {
+ {/* setup read ptr */
+ .addr = client->addr,
+ .len = 1,
+ .buf = &addr
+ },
+ {/* read control */
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 1,
+ .buf = status
+ },
+ };
+
+ /* read control register */
+ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+/* following are the sysfs callback functions */
+static ssize_t show_control(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ u8 control;
+ int err;
+
+ err = ds1672_get_control(client, &control);
+ if (err)
+ return err;
+
+ return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC)
+ ? "disabled" : "enabled");
+}
+
+static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);
+
+static const struct rtc_class_ops ds1672_rtc_ops = {
+ .read_time = ds1672_rtc_read_time,
+ .set_mmss = ds1672_rtc_set_mmss,
+};
+
+static int ds1672_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int err = 0;
+ u8 control;
+ struct rtc_device *rtc;
+
+ dev_dbg(&client->dev, "%s\n", __func__);
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ rtc = devm_rtc_device_register(&client->dev, ds1672_driver.driver.name,
+ &ds1672_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ i2c_set_clientdata(client, rtc);
+
+ /* read control register */
+ err = ds1672_get_control(client, &control);
+ if (err) {
+ dev_warn(&client->dev, "Unable to read the control register\n");
+ }
+
+ if (control & DS1672_REG_CONTROL_EOSC)
+ dev_warn(&client->dev, "Oscillator not enabled. "
+ "Set time to enable.\n");
+
+ /* Register sysfs hooks */
+ err = device_create_file(&client->dev, &dev_attr_control);
+ if (err)
+ dev_err(&client->dev, "Unable to create sysfs entry: %s\n",
+ dev_attr_control.attr.name);
+
+ return 0;
+}
+
+static const struct i2c_device_id ds1672_id[] = {
+ { "ds1672", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ds1672_id);
+
+static const struct of_device_id ds1672_of_match[] = {
+ { .compatible = "dallas,ds1672" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ds1672_of_match);
+
+static struct i2c_driver ds1672_driver = {
+ .driver = {
+ .name = "rtc-ds1672",
+ .of_match_table = of_match_ptr(ds1672_of_match),
+ },
+ .probe = &ds1672_probe,
+ .id_table = ds1672_id,
+};
+
+module_i2c_driver(ds1672_driver);
+
+MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
+MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
+MODULE_LICENSE("GPL");