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Diffstat (limited to 'drivers/rtc/rtc-em3027.c')
-rw-r--r--drivers/rtc/rtc-em3027.c158
1 files changed, 158 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-em3027.c b/drivers/rtc/rtc-em3027.c
new file mode 100644
index 000000000..53f9f9391
--- /dev/null
+++ b/drivers/rtc/rtc-em3027.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * An rtc/i2c driver for the EM Microelectronic EM3027
+ * Copyright 2011 CompuLab, Ltd.
+ *
+ * Author: Mike Rapoport <mike@compulab.co.il>
+ *
+ * Based on rtc-ds1672.c by Alessandro Zummo <a.zummo@towertech.it>
+ */
+
+#include <linux/i2c.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+/* Registers */
+#define EM3027_REG_ON_OFF_CTRL 0x00
+#define EM3027_REG_IRQ_CTRL 0x01
+#define EM3027_REG_IRQ_FLAGS 0x02
+#define EM3027_REG_STATUS 0x03
+#define EM3027_REG_RST_CTRL 0x04
+
+#define EM3027_REG_WATCH_SEC 0x08
+#define EM3027_REG_WATCH_MIN 0x09
+#define EM3027_REG_WATCH_HOUR 0x0a
+#define EM3027_REG_WATCH_DATE 0x0b
+#define EM3027_REG_WATCH_DAY 0x0c
+#define EM3027_REG_WATCH_MON 0x0d
+#define EM3027_REG_WATCH_YEAR 0x0e
+
+#define EM3027_REG_ALARM_SEC 0x10
+#define EM3027_REG_ALARM_MIN 0x11
+#define EM3027_REG_ALARM_HOUR 0x12
+#define EM3027_REG_ALARM_DATE 0x13
+#define EM3027_REG_ALARM_DAY 0x14
+#define EM3027_REG_ALARM_MON 0x15
+#define EM3027_REG_ALARM_YEAR 0x16
+
+static struct i2c_driver em3027_driver;
+
+static int em3027_get_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+
+ unsigned char addr = EM3027_REG_WATCH_SEC;
+ unsigned char buf[7];
+
+ struct i2c_msg msgs[] = {
+ {/* setup read addr */
+ .addr = client->addr,
+ .len = 1,
+ .buf = &addr
+ },
+ {/* read time/date */
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 7,
+ .buf = buf
+ },
+ };
+
+ /* read time/date registers */
+ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ return -EIO;
+ }
+
+ tm->tm_sec = bcd2bin(buf[0]);
+ tm->tm_min = bcd2bin(buf[1]);
+ tm->tm_hour = bcd2bin(buf[2]);
+ tm->tm_mday = bcd2bin(buf[3]);
+ tm->tm_wday = bcd2bin(buf[4]);
+ tm->tm_mon = bcd2bin(buf[5]) - 1;
+ tm->tm_year = bcd2bin(buf[6]) + 100;
+
+ return 0;
+}
+
+static int em3027_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned char buf[8];
+
+ struct i2c_msg msg = {
+ .addr = client->addr,
+ .len = 8,
+ .buf = buf, /* write time/date */
+ };
+
+ buf[0] = EM3027_REG_WATCH_SEC;
+ buf[1] = bin2bcd(tm->tm_sec);
+ buf[2] = bin2bcd(tm->tm_min);
+ buf[3] = bin2bcd(tm->tm_hour);
+ buf[4] = bin2bcd(tm->tm_mday);
+ buf[5] = bin2bcd(tm->tm_wday);
+ buf[6] = bin2bcd(tm->tm_mon + 1);
+ buf[7] = bin2bcd(tm->tm_year % 100);
+
+ /* write time/date registers */
+ if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {
+ dev_err(&client->dev, "%s: write error\n", __func__);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static const struct rtc_class_ops em3027_rtc_ops = {
+ .read_time = em3027_get_time,
+ .set_time = em3027_set_time,
+};
+
+static int em3027_probe(struct i2c_client *client)
+{
+ struct rtc_device *rtc;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ rtc = devm_rtc_device_register(&client->dev, em3027_driver.driver.name,
+ &em3027_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ i2c_set_clientdata(client, rtc);
+
+ return 0;
+}
+
+static const struct i2c_device_id em3027_id[] = {
+ { "em3027", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, em3027_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id em3027_of_match[] = {
+ { .compatible = "emmicro,em3027", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, em3027_of_match);
+#endif
+
+static struct i2c_driver em3027_driver = {
+ .driver = {
+ .name = "rtc-em3027",
+ .of_match_table = of_match_ptr(em3027_of_match),
+ },
+ .probe_new = em3027_probe,
+ .id_table = em3027_id,
+};
+
+module_i2c_driver(em3027_driver);
+
+MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
+MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");
+MODULE_LICENSE("GPL");