Fixed MTP to work with TWRP

drivers/rtc/rtc-ds3234.c

@@ -0,0 +1,172 @@
+/* rtc-ds3234.c
+ *
+ * Driver for Dallas Semiconductor (DS3234) SPI RTC with Integrated Crystal
+ * and SRAM.
+ *
+ * Copyright (C) 2008 MIMOMax Wireless Ltd.
+ *
+ * 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>
+
+#define DS3234_REG_SECONDS	0x00
+#define DS3234_REG_MINUTES	0x01
+#define DS3234_REG_HOURS	0x02
+#define DS3234_REG_DAY		0x03
+#define DS3234_REG_DATE		0x04
+#define DS3234_REG_MONTH	0x05
+#define DS3234_REG_YEAR		0x06
+#define DS3234_REG_CENTURY	(1 << 7) /* Bit 7 of the Month register */
+
+#define DS3234_REG_CONTROL	0x0E
+#define DS3234_REG_CONT_STAT	0x0F
+
+static int ds3234_set_reg(struct device *dev, unsigned char address,
+				unsigned char data)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	unsigned char buf[2];
+
+	/* MSB must be '1' to indicate write */
+	buf[0] = address | 0x80;
+	buf[1] = data;
+
+	return spi_write_then_read(spi, buf, 2, NULL, 0);
+}
+
+static int ds3234_get_reg(struct device *dev, unsigned char address,
+				unsigned char *data)
+{
+	struct spi_device *spi = to_spi_device(dev);
+
+	*data = address & 0x7f;
+
+	return spi_write_then_read(spi, data, 1, data, 1);
+}
+
+static int ds3234_read_time(struct device *dev, struct rtc_time *dt)
+{
+	int err;
+	unsigned char buf[8];
+	struct spi_device *spi = to_spi_device(dev);
+
+	buf[0] = 0x00; /* Start address */
+
+	err = spi_write_then_read(spi, buf, 1, buf, 8);
+	if (err != 0)
+		return err;
+
+	/* Seconds, Minutes, Hours, Day, Date, Month, Year */
+	dt->tm_sec	= bcd2bin(buf[0]);
+	dt->tm_min	= bcd2bin(buf[1]);
+	dt->tm_hour	= bcd2bin(buf[2] & 0x3f);
+	dt->tm_wday	= bcd2bin(buf[3]) - 1; /* 0 = Sun */
+	dt->tm_mday	= bcd2bin(buf[4]);
+	dt->tm_mon	= bcd2bin(buf[5] & 0x1f) - 1; /* 0 = Jan */
+	dt->tm_year	= bcd2bin(buf[6] & 0xff) + 100; /* Assume 20YY */
+
+	return rtc_valid_tm(dt);
+}
+
+static int ds3234_set_time(struct device *dev, struct rtc_time *dt)
+{
+	ds3234_set_reg(dev, DS3234_REG_SECONDS, bin2bcd(dt->tm_sec));
+	ds3234_set_reg(dev, DS3234_REG_MINUTES, bin2bcd(dt->tm_min));
+	ds3234_set_reg(dev, DS3234_REG_HOURS, bin2bcd(dt->tm_hour) & 0x3f);
+
+	/* 0 = Sun */
+	ds3234_set_reg(dev, DS3234_REG_DAY, bin2bcd(dt->tm_wday + 1));
+	ds3234_set_reg(dev, DS3234_REG_DATE, bin2bcd(dt->tm_mday));
+
+	/* 0 = Jan */
+	ds3234_set_reg(dev, DS3234_REG_MONTH, bin2bcd(dt->tm_mon + 1));
+
+	/* Assume 20YY although we just want to make sure not to go negative. */
+	if (dt->tm_year > 100)
+		dt->tm_year -= 100;
+
+	ds3234_set_reg(dev, DS3234_REG_YEAR, bin2bcd(dt->tm_year));
+
+	return 0;
+}
+
+static const struct rtc_class_ops ds3234_rtc_ops = {
+	.read_time	= ds3234_read_time,
+	.set_time	= ds3234_set_time,
+};
+
+static int ds3234_probe(struct spi_device *spi)
+{
+	struct rtc_device *rtc;
+	unsigned char tmp;
+	int res;
+
+	spi->mode = SPI_MODE_3;
+	spi->bits_per_word = 8;
+	spi_setup(spi);
+
+	res = ds3234_get_reg(&spi->dev, DS3234_REG_SECONDS, &tmp);
+	if (res != 0)
+		return res;
+
+	/* Control settings
+	 *
+	 * CONTROL_REG
+	 * BIT 7	6	5	4	3	2	1	0
+	 *     EOSC	BBSQW	CONV	RS2	RS1	INTCN	A2IE	A1IE
+	 *
+	 *     0	0	0	1	1	1	0	0
+	 *
+	 * CONTROL_STAT_REG
+	 * BIT 7	6	5	4	3	2	1	0
+	 *     OSF	BB32kHz	CRATE1	CRATE0	EN32kHz	BSY	A2F	A1F
+	 *
+	 *     1	0	0	0	1	0	0	0
+	 */
+	ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp);
+	ds3234_set_reg(&spi->dev, DS3234_REG_CONTROL, tmp & 0x1c);
+
+	ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp);
+	ds3234_set_reg(&spi->dev, DS3234_REG_CONT_STAT, tmp & 0x88);
+
+	/* Print our settings */
+	ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp);
+	dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp);
+
+	ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp);
+	dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp);
+
+	rtc = devm_rtc_device_register(&spi->dev, "ds3234",
+				&ds3234_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+
+	spi_set_drvdata(spi, rtc);
+
+	return 0;
+}
+
+static struct spi_driver ds3234_driver = {
+	.driver = {
+		.name	 = "ds3234",
+		.owner	= THIS_MODULE,
+	},
+	.probe	 = ds3234_probe,
+};
+
+module_spi_driver(ds3234_driver);
+
+MODULE_DESCRIPTION("DS3234 SPI RTC driver");
+MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:ds3234");