Fixed MTP to work with TWRP

drivers/rtc/rtc-r9701.c

@@ -0,0 +1,186 @@
+/*
+ * Driver for Epson RTC-9701JE
+ *
+ * Copyright (C) 2008 Magnus Damm
+ *
+ * Based on rtc-max6902.c
+ *
+ * Copyright (C) 2006 8D Technologies inc.
+ * Copyright (C) 2004 Compulab 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/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/rtc.h>
+#include <linux/spi/spi.h>
+#include <linux/bcd.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+
+#define RSECCNT	0x00	/* Second Counter */
+#define RMINCNT	0x01	/* Minute Counter */
+#define RHRCNT	0x02	/* Hour Counter */
+#define RWKCNT	0x03	/* Week Counter */
+#define RDAYCNT	0x04	/* Day Counter */
+#define RMONCNT	0x05	/* Month Counter */
+#define RYRCNT	0x06	/* Year Counter */
+#define R100CNT	0x07	/* Y100 Counter */
+#define RMINAR	0x08	/* Minute Alarm */
+#define RHRAR	0x09	/* Hour Alarm */
+#define RWKAR	0x0a	/* Week/Day Alarm */
+#define RTIMCNT	0x0c	/* Interval Timer */
+#define REXT	0x0d	/* Extension Register */
+#define RFLAG	0x0e	/* RTC Flag Register */
+#define RCR	0x0f	/* RTC Control Register */
+
+static int write_reg(struct device *dev, int address, unsigned char data)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	unsigned char buf[2];
+
+	buf[0] = address & 0x7f;
+	buf[1] = data;
+
+	return spi_write(spi, buf, ARRAY_SIZE(buf));
+}
+
+static int read_regs(struct device *dev, unsigned char *regs, int no_regs)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	u8 txbuf[1], rxbuf[1];
+	int k, ret;
+
+	ret = 0;
+
+	for (k = 0; ret == 0 && k < no_regs; k++) {
+		txbuf[0] = 0x80 | regs[k];
+		ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
+		regs[k] = rxbuf[0];
+	}
+
+	return ret;
+}
+
+static int r9701_get_datetime(struct device *dev, struct rtc_time *dt)
+{
+	int ret;
+	unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT,
+				RDAYCNT, RMONCNT, RYRCNT };
+
+	ret = read_regs(dev, buf, ARRAY_SIZE(buf));
+	if (ret)
+		return ret;
+
+	memset(dt, 0, sizeof(*dt));
+
+	dt->tm_sec = bcd2bin(buf[0]); /* RSECCNT */
+	dt->tm_min = bcd2bin(buf[1]); /* RMINCNT */
+	dt->tm_hour = bcd2bin(buf[2]); /* RHRCNT */
+
+	dt->tm_mday = bcd2bin(buf[3]); /* RDAYCNT */
+	dt->tm_mon = bcd2bin(buf[4]) - 1; /* RMONCNT */
+	dt->tm_year = bcd2bin(buf[5]) + 100; /* RYRCNT */
+
+	/* the rtc device may contain illegal values on power up
+	 * according to the data sheet. make sure they are valid.
+	 */
+
+	return rtc_valid_tm(dt);
+}
+
+static int r9701_set_datetime(struct device *dev, struct rtc_time *dt)
+{
+	int ret, year;
+
+	year = dt->tm_year + 1900;
+	if (year >= 2100 || year < 2000)
+		return -EINVAL;
+
+	ret = write_reg(dev, RHRCNT, bin2bcd(dt->tm_hour));
+	ret = ret ? ret : write_reg(dev, RMINCNT, bin2bcd(dt->tm_min));
+	ret = ret ? ret : write_reg(dev, RSECCNT, bin2bcd(dt->tm_sec));
+	ret = ret ? ret : write_reg(dev, RDAYCNT, bin2bcd(dt->tm_mday));
+	ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1));
+	ret = ret ? ret : write_reg(dev, RYRCNT, bin2bcd(dt->tm_year - 100));
+	ret = ret ? ret : write_reg(dev, RWKCNT, 1 << dt->tm_wday);
+
+	return ret;
+}
+
+static const struct rtc_class_ops r9701_rtc_ops = {
+	.read_time	= r9701_get_datetime,
+	.set_time	= r9701_set_datetime,
+};
+
+static int r9701_probe(struct spi_device *spi)
+{
+	struct rtc_device *rtc;
+	struct rtc_time dt;
+	unsigned char tmp;
+	int res;
+
+	tmp = R100CNT;
+	res = read_regs(&spi->dev, &tmp, 1);
+	if (res || tmp != 0x20) {
+		dev_err(&spi->dev, "cannot read RTC register\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * The device seems to be present. Now check if the registers
+	 * contain invalid values. If so, try to write a default date:
+	 * 2000/1/1 00:00:00
+	 */
+	if (r9701_get_datetime(&spi->dev, &dt)) {
+		dev_info(&spi->dev, "trying to repair invalid date/time\n");
+		dt.tm_sec  = 0;
+		dt.tm_min  = 0;
+		dt.tm_hour = 0;
+		dt.tm_mday = 1;
+		dt.tm_mon  = 0;
+		dt.tm_year = 100;
+
+		if (r9701_set_datetime(&spi->dev, &dt) ||
+				r9701_get_datetime(&spi->dev, &dt)) {
+			dev_err(&spi->dev, "cannot repair RTC register\n");
+			return -ENODEV;
+		}
+	}
+
+	rtc = devm_rtc_device_register(&spi->dev, "r9701",
+				&r9701_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+
+	spi_set_drvdata(spi, rtc);
+
+	return 0;
+}
+
+static int r9701_remove(struct spi_device *spi)
+{
+	return 0;
+}
+
+static struct spi_driver r9701_driver = {
+	.driver = {
+		.name	= "rtc-r9701",
+		.owner	= THIS_MODULE,
+	},
+	.probe	= r9701_probe,
+	.remove = r9701_remove,
+};
+
+module_spi_driver(r9701_driver);
+
+MODULE_DESCRIPTION("r9701 spi RTC driver");
+MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:rtc-r9701");