Fixed MTP to work with TWRP

drivers/rtc/rtc-ds1672.c

@@ -0,0 +1,215 @@
+/*
+ * 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>
+
+#define DRV_VERSION "0.4"
+
+/* 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;
+
+	dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+
+	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 struct i2c_device_id ds1672_id[] = {
+	{ "ds1672", 0 },
+	{ }
+};
+
+static struct i2c_driver ds1672_driver = {
+	.driver = {
+		   .name = "rtc-ds1672",
+		   },
+	.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");
+MODULE_VERSION(DRV_VERSION);