v4.19.13 snapshot.
diff --git a/drivers/rtc/rtc-v3020.c b/drivers/rtc/rtc-v3020.c
new file mode 100644
index 0000000..1f3117b
--- /dev/null
+++ b/drivers/rtc/rtc-v3020.c
@@ -0,0 +1,374 @@
+/* drivers/rtc/rtc-v3020.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.
+ *
+ * Driver for the V3020 RTC
+ *
+ * Changelog:
+ *
+ *  10-May-2006: Raphael Assenat <raph@8d.com>
+ *				- Converted to platform driver
+ *				- Use the generic rtc class
+ *
+ *  ??-???-2004: Someone at Compulab
+ *			- Initial driver creation.
+ *
+ */
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rtc.h>
+#include <linux/types.h>
+#include <linux/bcd.h>
+#include <linux/platform_data/rtc-v3020.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/slab.h>
+
+#include <linux/io.h>
+
+#undef DEBUG
+
+struct v3020;
+
+struct v3020_chip_ops {
+	int (*map_io)(struct v3020 *chip, struct platform_device *pdev,
+		      struct v3020_platform_data *pdata);
+	void (*unmap_io)(struct v3020 *chip);
+	unsigned char (*read_bit)(struct v3020 *chip);
+	void (*write_bit)(struct v3020 *chip, unsigned char bit);
+};
+
+#define V3020_CS	0
+#define V3020_WR	1
+#define V3020_RD	2
+#define V3020_IO	3
+
+struct v3020 {
+	/* MMIO access */
+	void __iomem *ioaddress;
+	int leftshift;
+
+	/* GPIO access */
+	struct gpio *gpio;
+
+	const struct v3020_chip_ops *ops;
+
+	struct rtc_device *rtc;
+};
+
+
+static int v3020_mmio_map(struct v3020 *chip, struct platform_device *pdev,
+			  struct v3020_platform_data *pdata)
+{
+	if (pdev->num_resources != 1)
+		return -EBUSY;
+
+	if (pdev->resource[0].flags != IORESOURCE_MEM)
+		return -EBUSY;
+
+	chip->leftshift = pdata->leftshift;
+	chip->ioaddress = ioremap(pdev->resource[0].start, 1);
+	if (chip->ioaddress == NULL)
+		return -EBUSY;
+
+	return 0;
+}
+
+static void v3020_mmio_unmap(struct v3020 *chip)
+{
+	iounmap(chip->ioaddress);
+}
+
+static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
+{
+	writel(bit << chip->leftshift, chip->ioaddress);
+}
+
+static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
+{
+	return !!(readl(chip->ioaddress) & (1 << chip->leftshift));
+}
+
+static const struct v3020_chip_ops v3020_mmio_ops = {
+	.map_io		= v3020_mmio_map,
+	.unmap_io	= v3020_mmio_unmap,
+	.read_bit	= v3020_mmio_read_bit,
+	.write_bit	= v3020_mmio_write_bit,
+};
+
+static struct gpio v3020_gpio[] = {
+	{ 0, GPIOF_OUT_INIT_HIGH, "RTC CS"},
+	{ 0, GPIOF_OUT_INIT_HIGH, "RTC WR"},
+	{ 0, GPIOF_OUT_INIT_HIGH, "RTC RD"},
+	{ 0, GPIOF_OUT_INIT_HIGH, "RTC IO"},
+};
+
+static int v3020_gpio_map(struct v3020 *chip, struct platform_device *pdev,
+			  struct v3020_platform_data *pdata)
+{
+	int err;
+
+	v3020_gpio[V3020_CS].gpio = pdata->gpio_cs;
+	v3020_gpio[V3020_WR].gpio = pdata->gpio_wr;
+	v3020_gpio[V3020_RD].gpio = pdata->gpio_rd;
+	v3020_gpio[V3020_IO].gpio = pdata->gpio_io;
+
+	err = gpio_request_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
+
+	if (!err)
+		chip->gpio = v3020_gpio;
+
+	return err;
+}
+
+static void v3020_gpio_unmap(struct v3020 *chip)
+{
+	gpio_free_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
+}
+
+static void v3020_gpio_write_bit(struct v3020 *chip, unsigned char bit)
+{
+	gpio_direction_output(chip->gpio[V3020_IO].gpio, bit);
+	gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
+	gpio_set_value(chip->gpio[V3020_WR].gpio, 0);
+	udelay(1);
+	gpio_set_value(chip->gpio[V3020_WR].gpio, 1);
+	gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
+}
+
+static unsigned char v3020_gpio_read_bit(struct v3020 *chip)
+{
+	int bit;
+
+	gpio_direction_input(chip->gpio[V3020_IO].gpio);
+	gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
+	gpio_set_value(chip->gpio[V3020_RD].gpio, 0);
+	udelay(1);
+	bit = !!gpio_get_value(chip->gpio[V3020_IO].gpio);
+	udelay(1);
+	gpio_set_value(chip->gpio[V3020_RD].gpio, 1);
+	gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
+
+	return bit;
+}
+
+static const struct v3020_chip_ops v3020_gpio_ops = {
+	.map_io		= v3020_gpio_map,
+	.unmap_io	= v3020_gpio_unmap,
+	.read_bit	= v3020_gpio_read_bit,
+	.write_bit	= v3020_gpio_write_bit,
+};
+
+static void v3020_set_reg(struct v3020 *chip, unsigned char address,
+			unsigned char data)
+{
+	int i;
+	unsigned char tmp;
+
+	tmp = address;
+	for (i = 0; i < 4; i++) {
+		chip->ops->write_bit(chip, (tmp & 1));
+		tmp >>= 1;
+		udelay(1);
+	}
+
+	/* Commands dont have data */
+	if (!V3020_IS_COMMAND(address)) {
+		for (i = 0; i < 8; i++) {
+			chip->ops->write_bit(chip, (data & 1));
+			data >>= 1;
+			udelay(1);
+		}
+	}
+}
+
+static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
+{
+	unsigned int data = 0;
+	int i;
+
+	for (i = 0; i < 4; i++) {
+		chip->ops->write_bit(chip, (address & 1));
+		address >>= 1;
+		udelay(1);
+	}
+
+	for (i = 0; i < 8; i++) {
+		data >>= 1;
+		if (chip->ops->read_bit(chip))
+			data |= 0x80;
+		udelay(1);
+	}
+
+	return data;
+}
+
+static int v3020_read_time(struct device *dev, struct rtc_time *dt)
+{
+	struct v3020 *chip = dev_get_drvdata(dev);
+	int tmp;
+
+	/* Copy the current time to ram... */
+	v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);
+
+	/* ...and then read constant values. */
+	tmp = v3020_get_reg(chip, V3020_SECONDS);
+	dt->tm_sec	= bcd2bin(tmp);
+	tmp = v3020_get_reg(chip, V3020_MINUTES);
+	dt->tm_min	= bcd2bin(tmp);
+	tmp = v3020_get_reg(chip, V3020_HOURS);
+	dt->tm_hour	= bcd2bin(tmp);
+	tmp = v3020_get_reg(chip, V3020_MONTH_DAY);
+	dt->tm_mday	= bcd2bin(tmp);
+	tmp = v3020_get_reg(chip, V3020_MONTH);
+	dt->tm_mon    = bcd2bin(tmp) - 1;
+	tmp = v3020_get_reg(chip, V3020_WEEK_DAY);
+	dt->tm_wday	= bcd2bin(tmp);
+	tmp = v3020_get_reg(chip, V3020_YEAR);
+	dt->tm_year = bcd2bin(tmp)+100;
+
+	dev_dbg(dev, "\n%s : Read RTC values\n", __func__);
+	dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
+	dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
+	dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
+	dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
+	dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
+	dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
+	dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
+
+	return 0;
+}
+
+
+static int v3020_set_time(struct device *dev, struct rtc_time *dt)
+{
+	struct v3020 *chip = dev_get_drvdata(dev);
+
+	dev_dbg(dev, "\n%s : Setting RTC values\n", __func__);
+	dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
+	dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
+	dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
+	dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
+	dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
+	dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
+
+	/* Write all the values to ram... */
+	v3020_set_reg(chip, V3020_SECONDS,	bin2bcd(dt->tm_sec));
+	v3020_set_reg(chip, V3020_MINUTES,	bin2bcd(dt->tm_min));
+	v3020_set_reg(chip, V3020_HOURS,	bin2bcd(dt->tm_hour));
+	v3020_set_reg(chip, V3020_MONTH_DAY,	bin2bcd(dt->tm_mday));
+	v3020_set_reg(chip, V3020_MONTH,	bin2bcd(dt->tm_mon + 1));
+	v3020_set_reg(chip, V3020_WEEK_DAY,	bin2bcd(dt->tm_wday));
+	v3020_set_reg(chip, V3020_YEAR,		bin2bcd(dt->tm_year % 100));
+
+	/* ...and set the clock. */
+	v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);
+
+	/* Compulab used this delay here. I dont know why,
+	 * the datasheet does not specify a delay. */
+	/*mdelay(5);*/
+
+	return 0;
+}
+
+static const struct rtc_class_ops v3020_rtc_ops = {
+	.read_time	= v3020_read_time,
+	.set_time	= v3020_set_time,
+};
+
+static int rtc_probe(struct platform_device *pdev)
+{
+	struct v3020_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct v3020 *chip;
+	int retval = -EBUSY;
+	int i;
+	int temp;
+
+	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	if (pdata->use_gpio)
+		chip->ops = &v3020_gpio_ops;
+	else
+		chip->ops = &v3020_mmio_ops;
+
+	retval = chip->ops->map_io(chip, pdev, pdata);
+	if (retval)
+		return retval;
+
+	/* Make sure the v3020 expects a communication cycle
+	 * by reading 8 times */
+	for (i = 0; i < 8; i++)
+		temp = chip->ops->read_bit(chip);
+
+	/* Test chip by doing a write/read sequence
+	 * to the chip ram */
+	v3020_set_reg(chip, V3020_SECONDS, 0x33);
+	if (v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
+		retval = -ENODEV;
+		goto err_io;
+	}
+
+	/* Make sure frequency measurement mode, test modes, and lock
+	 * are all disabled */
+	v3020_set_reg(chip, V3020_STATUS_0, 0x0);
+
+	if (pdata->use_gpio)
+		dev_info(&pdev->dev, "Chip available at GPIOs "
+			 "%d, %d, %d, %d\n",
+			 chip->gpio[V3020_CS].gpio, chip->gpio[V3020_WR].gpio,
+			 chip->gpio[V3020_RD].gpio, chip->gpio[V3020_IO].gpio);
+	else
+		dev_info(&pdev->dev, "Chip available at "
+			 "physical address 0x%llx,"
+			 "data connected to D%d\n",
+			 (unsigned long long)pdev->resource[0].start,
+			 chip->leftshift);
+
+	platform_set_drvdata(pdev, chip);
+
+	chip->rtc = devm_rtc_device_register(&pdev->dev, "v3020",
+					&v3020_rtc_ops, THIS_MODULE);
+	if (IS_ERR(chip->rtc)) {
+		retval = PTR_ERR(chip->rtc);
+		goto err_io;
+	}
+
+	return 0;
+
+err_io:
+	chip->ops->unmap_io(chip);
+
+	return retval;
+}
+
+static int rtc_remove(struct platform_device *dev)
+{
+	struct v3020 *chip = platform_get_drvdata(dev);
+
+	chip->ops->unmap_io(chip);
+
+	return 0;
+}
+
+static struct platform_driver rtc_device_driver = {
+	.probe	= rtc_probe,
+	.remove = rtc_remove,
+	.driver = {
+		.name	= "v3020",
+	},
+};
+
+module_platform_driver(rtc_device_driver);
+
+MODULE_DESCRIPTION("V3020 RTC");
+MODULE_AUTHOR("Raphael Assenat");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:v3020");