v4.19.13 snapshot.
diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
new file mode 100644
index 0000000..945bd13
--- /dev/null
+++ b/drivers/gpio/gpio-mockup.c
@@ -0,0 +1,412 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * GPIO Testing Device Driver
+ *
+ * Copyright (C) 2014  Kamlakant Patel <kamlakant.patel@broadcom.com>
+ * Copyright (C) 2015-2016  Bamvor Jian Zhang <bamv2005@gmail.com>
+ * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irq_sim.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+
+#include "gpiolib.h"
+
+#define GPIO_MOCKUP_NAME	"gpio-mockup"
+#define GPIO_MOCKUP_MAX_GC	10
+/*
+ * We're storing two values per chip: the GPIO base and the number
+ * of GPIO lines.
+ */
+#define GPIO_MOCKUP_MAX_RANGES	(GPIO_MOCKUP_MAX_GC * 2)
+
+#define gpio_mockup_err(...)	pr_err(GPIO_MOCKUP_NAME ": " __VA_ARGS__)
+
+enum {
+	GPIO_MOCKUP_DIR_IN = 0,
+	GPIO_MOCKUP_DIR_OUT = 1,
+};
+
+/*
+ * struct gpio_pin_status - structure describing a GPIO status
+ * @dir:       Configures direction of gpio as "in" or "out", 0=in, 1=out
+ * @value:     Configures status of the gpio as 0(low) or 1(high)
+ */
+struct gpio_mockup_line_status {
+	int dir;
+	int value;
+};
+
+struct gpio_mockup_chip {
+	struct gpio_chip gc;
+	struct gpio_mockup_line_status *lines;
+	struct irq_sim irqsim;
+	struct dentry *dbg_dir;
+};
+
+struct gpio_mockup_dbgfs_private {
+	struct gpio_mockup_chip *chip;
+	struct gpio_desc *desc;
+	int offset;
+};
+
+struct gpio_mockup_platform_data {
+	int base;
+	int ngpio;
+	int index;
+	bool named_lines;
+};
+
+static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES];
+static int gpio_mockup_num_ranges;
+module_param_array(gpio_mockup_ranges, int, &gpio_mockup_num_ranges, 0400);
+
+static bool gpio_mockup_named_lines;
+module_param_named(gpio_mockup_named_lines,
+		   gpio_mockup_named_lines, bool, 0400);
+
+static struct dentry *gpio_mockup_dbg_dir;
+
+static int gpio_mockup_range_base(unsigned int index)
+{
+	return gpio_mockup_ranges[index * 2];
+}
+
+static int gpio_mockup_range_ngpio(unsigned int index)
+{
+	return gpio_mockup_ranges[index * 2 + 1];
+}
+
+static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
+{
+	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+	return chip->lines[offset].value;
+}
+
+static void gpio_mockup_set(struct gpio_chip *gc,
+			    unsigned int offset, int value)
+{
+	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+	chip->lines[offset].value = !!value;
+}
+
+static void gpio_mockup_set_multiple(struct gpio_chip *gc,
+				     unsigned long *mask, unsigned long *bits)
+{
+	unsigned int bit;
+
+	for_each_set_bit(bit, mask, gc->ngpio)
+		gpio_mockup_set(gc, bit, test_bit(bit, bits));
+
+}
+
+static int gpio_mockup_dirout(struct gpio_chip *gc,
+			      unsigned int offset, int value)
+{
+	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+	gpio_mockup_set(gc, offset, value);
+	chip->lines[offset].dir = GPIO_MOCKUP_DIR_OUT;
+
+	return 0;
+}
+
+static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
+{
+	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+	chip->lines[offset].dir = GPIO_MOCKUP_DIR_IN;
+
+	return 0;
+}
+
+static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+	return !chip->lines[offset].dir;
+}
+
+static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
+{
+	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+	return irq_sim_irqnum(&chip->irqsim, offset);
+}
+
+static ssize_t gpio_mockup_event_write(struct file *file,
+				       const char __user *usr_buf,
+				       size_t size, loff_t *ppos)
+{
+	struct gpio_mockup_dbgfs_private *priv;
+	struct gpio_mockup_chip *chip;
+	struct seq_file *sfile;
+	struct gpio_desc *desc;
+	int rv, val;
+
+	rv = kstrtoint_from_user(usr_buf, size, 0, &val);
+	if (rv)
+		return rv;
+	if (val != 0 && val != 1)
+		return -EINVAL;
+
+	sfile = file->private_data;
+	priv = sfile->private;
+	desc = priv->desc;
+	chip = priv->chip;
+
+	gpiod_set_value_cansleep(desc, val);
+	irq_sim_fire(&chip->irqsim, priv->offset);
+
+	return size;
+}
+
+static int gpio_mockup_event_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, NULL, inode->i_private);
+}
+
+static const struct file_operations gpio_mockup_event_ops = {
+	.owner = THIS_MODULE,
+	.open = gpio_mockup_event_open,
+	.write = gpio_mockup_event_write,
+	.llseek = no_llseek,
+};
+
+static void gpio_mockup_debugfs_setup(struct device *dev,
+				      struct gpio_mockup_chip *chip)
+{
+	struct gpio_mockup_dbgfs_private *priv;
+	struct dentry *evfile, *link;
+	struct gpio_chip *gc;
+	const char *devname;
+	char *name;
+	int i;
+
+	gc = &chip->gc;
+	devname = dev_name(&gc->gpiodev->dev);
+
+	chip->dbg_dir = debugfs_create_dir(devname, gpio_mockup_dbg_dir);
+	if (IS_ERR_OR_NULL(chip->dbg_dir))
+		goto err;
+
+	link = debugfs_create_symlink(gc->label, gpio_mockup_dbg_dir, devname);
+	if (IS_ERR_OR_NULL(link))
+		goto err;
+
+	for (i = 0; i < gc->ngpio; i++) {
+		name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
+		if (!name)
+			goto err;
+
+		priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+		if (!priv)
+			goto err;
+
+		priv->chip = chip;
+		priv->offset = i;
+		priv->desc = &gc->gpiodev->descs[i];
+
+		evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv,
+					     &gpio_mockup_event_ops);
+		if (IS_ERR_OR_NULL(evfile))
+			goto err;
+	}
+
+	return;
+
+err:
+	dev_err(dev, "error creating debugfs event files\n");
+}
+
+static int gpio_mockup_name_lines(struct device *dev,
+				  struct gpio_mockup_chip *chip)
+{
+	struct gpio_chip *gc = &chip->gc;
+	char **names;
+	int i;
+
+	names = devm_kcalloc(dev, gc->ngpio, sizeof(char *), GFP_KERNEL);
+	if (!names)
+		return -ENOMEM;
+
+	for (i = 0; i < gc->ngpio; i++) {
+		names[i] = devm_kasprintf(dev, GFP_KERNEL,
+					  "%s-%d", gc->label, i);
+		if (!names[i])
+			return -ENOMEM;
+	}
+
+	gc->names = (const char *const *)names;
+
+	return 0;
+}
+
+static int gpio_mockup_probe(struct platform_device *pdev)
+{
+	struct gpio_mockup_platform_data *pdata;
+	struct gpio_mockup_chip *chip;
+	struct gpio_chip *gc;
+	int rv, base, ngpio;
+	struct device *dev;
+	char *name;
+
+	dev = &pdev->dev;
+	pdata = dev_get_platdata(dev);
+	base = pdata->base;
+	ngpio = pdata->ngpio;
+
+	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	name = devm_kasprintf(dev, GFP_KERNEL, "%s-%c",
+			      pdev->name, pdata->index);
+	if (!name)
+		return -ENOMEM;
+
+	gc = &chip->gc;
+	gc->base = base;
+	gc->ngpio = ngpio;
+	gc->label = name;
+	gc->owner = THIS_MODULE;
+	gc->parent = dev;
+	gc->get = gpio_mockup_get;
+	gc->set = gpio_mockup_set;
+	gc->set_multiple = gpio_mockup_set_multiple;
+	gc->direction_output = gpio_mockup_dirout;
+	gc->direction_input = gpio_mockup_dirin;
+	gc->get_direction = gpio_mockup_get_direction;
+	gc->to_irq = gpio_mockup_to_irq;
+
+	chip->lines = devm_kcalloc(dev, gc->ngpio,
+				   sizeof(*chip->lines), GFP_KERNEL);
+	if (!chip->lines)
+		return -ENOMEM;
+
+	if (pdata->named_lines) {
+		rv = gpio_mockup_name_lines(dev, chip);
+		if (rv)
+			return rv;
+	}
+
+	rv = devm_irq_sim_init(dev, &chip->irqsim, gc->ngpio);
+	if (rv < 0)
+		return rv;
+
+	rv = devm_gpiochip_add_data(dev, &chip->gc, chip);
+	if (rv)
+		return rv;
+
+	if (!IS_ERR_OR_NULL(gpio_mockup_dbg_dir))
+		gpio_mockup_debugfs_setup(dev, chip);
+
+	return 0;
+}
+
+static struct platform_driver gpio_mockup_driver = {
+	.driver = {
+		.name = GPIO_MOCKUP_NAME,
+	},
+	.probe = gpio_mockup_probe,
+};
+
+static struct platform_device *gpio_mockup_pdevs[GPIO_MOCKUP_MAX_GC];
+
+static void gpio_mockup_unregister_pdevs(void)
+{
+	struct platform_device *pdev;
+	int i;
+
+	for (i = 0; i < GPIO_MOCKUP_MAX_GC; i++) {
+		pdev = gpio_mockup_pdevs[i];
+
+		if (pdev)
+			platform_device_unregister(pdev);
+	}
+}
+
+static int __init gpio_mockup_init(void)
+{
+	int i, num_chips, err = 0, index = 'A';
+	struct gpio_mockup_platform_data pdata;
+	struct platform_device *pdev;
+
+	if ((gpio_mockup_num_ranges < 2) ||
+	    (gpio_mockup_num_ranges % 2) ||
+	    (gpio_mockup_num_ranges > GPIO_MOCKUP_MAX_RANGES))
+		return -EINVAL;
+
+	/* Each chip is described by two values. */
+	num_chips = gpio_mockup_num_ranges / 2;
+
+	/*
+	 * The second value in the <base GPIO - number of GPIOS> pair must
+	 * always be greater than 0.
+	 */
+	for (i = 0; i < num_chips; i++) {
+		if (gpio_mockup_range_ngpio(i) < 0)
+			return -EINVAL;
+	}
+
+	gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL);
+	if (IS_ERR_OR_NULL(gpio_mockup_dbg_dir))
+		gpio_mockup_err("error creating debugfs directory\n");
+
+	err = platform_driver_register(&gpio_mockup_driver);
+	if (err) {
+		gpio_mockup_err("error registering platform driver\n");
+		return err;
+	}
+
+	for (i = 0; i < num_chips; i++) {
+		pdata.index = index++;
+		pdata.base = gpio_mockup_range_base(i);
+		pdata.ngpio = pdata.base < 0
+				? gpio_mockup_range_ngpio(i)
+				: gpio_mockup_range_ngpio(i) - pdata.base;
+		pdata.named_lines = gpio_mockup_named_lines;
+
+		pdev = platform_device_register_resndata(NULL,
+							 GPIO_MOCKUP_NAME,
+							 i, NULL, 0, &pdata,
+							 sizeof(pdata));
+		if (IS_ERR(pdev)) {
+			gpio_mockup_err("error registering device");
+			platform_driver_unregister(&gpio_mockup_driver);
+			gpio_mockup_unregister_pdevs();
+			return PTR_ERR(pdev);
+		}
+
+		gpio_mockup_pdevs[i] = pdev;
+	}
+
+	return 0;
+}
+
+static void __exit gpio_mockup_exit(void)
+{
+	debugfs_remove_recursive(gpio_mockup_dbg_dir);
+	platform_driver_unregister(&gpio_mockup_driver);
+	gpio_mockup_unregister_pdevs();
+}
+
+module_init(gpio_mockup_init);
+module_exit(gpio_mockup_exit);
+
+MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
+MODULE_AUTHOR("Bamvor Jian Zhang <bamv2005@gmail.com>");
+MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>");
+MODULE_DESCRIPTION("GPIO Testing driver");
+MODULE_LICENSE("GPL v2");