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path: root/drivers/gpio/gpio-mockup.c
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-rw-r--r--drivers/gpio/gpio-mockup.c614
1 files changed, 614 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
new file mode 100644
index 000000000..72a369cf8
--- /dev/null
+++ b/drivers/gpio/gpio-mockup.c
@@ -0,0 +1,614 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/debugfs.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irq_sim.h>
+#include <linux/irqdomain.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/string_helpers.h>
+#include <linux/uaccess.h>
+
+#include "gpiolib.h"
+
+#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)
+/* Maximum of four properties + the sentinel. */
+#define GPIO_MOCKUP_MAX_PROP 5
+
+/*
+ * struct gpio_pin_status - structure describing a GPIO status
+ * @dir: Configures direction of gpio as "in" or "out"
+ * @value: Configures status of the gpio as 0(low) or 1(high)
+ */
+struct gpio_mockup_line_status {
+ int dir;
+ int value;
+ int pull;
+};
+
+struct gpio_mockup_chip {
+ struct gpio_chip gc;
+ struct gpio_mockup_line_status *lines;
+ struct irq_domain *irq_sim_domain;
+ struct dentry *dbg_dir;
+ struct mutex lock;
+};
+
+struct gpio_mockup_dbgfs_private {
+ struct gpio_mockup_chip *chip;
+ struct gpio_desc *desc;
+ unsigned int offset;
+};
+
+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_mockup_chip *chip,
+ unsigned int offset)
+{
+ return chip->lines[offset].value;
+}
+
+static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
+{
+ struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+ int val;
+
+ mutex_lock(&chip->lock);
+ val = __gpio_mockup_get(chip, offset);
+ mutex_unlock(&chip->lock);
+
+ return val;
+}
+
+static int gpio_mockup_get_multiple(struct gpio_chip *gc,
+ unsigned long *mask, unsigned long *bits)
+{
+ struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+ unsigned int bit, val;
+
+ mutex_lock(&chip->lock);
+ for_each_set_bit(bit, mask, gc->ngpio) {
+ val = __gpio_mockup_get(chip, bit);
+ __assign_bit(bit, bits, val);
+ }
+ mutex_unlock(&chip->lock);
+
+ return 0;
+}
+
+static void __gpio_mockup_set(struct gpio_mockup_chip *chip,
+ unsigned int offset, int value)
+{
+ chip->lines[offset].value = !!value;
+}
+
+static void gpio_mockup_set(struct gpio_chip *gc,
+ unsigned int offset, int value)
+{
+ struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+ mutex_lock(&chip->lock);
+ __gpio_mockup_set(chip, offset, value);
+ mutex_unlock(&chip->lock);
+}
+
+static void gpio_mockup_set_multiple(struct gpio_chip *gc,
+ unsigned long *mask, unsigned long *bits)
+{
+ struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+ unsigned int bit;
+
+ mutex_lock(&chip->lock);
+ for_each_set_bit(bit, mask, gc->ngpio)
+ __gpio_mockup_set(chip, bit, test_bit(bit, bits));
+ mutex_unlock(&chip->lock);
+}
+
+static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip,
+ unsigned int offset, int value)
+{
+ struct gpio_chip *gc = &chip->gc;
+ struct gpio_desc *desc = gpiochip_get_desc(gc, offset);
+ int curr, irq, irq_type, ret = 0;
+
+ mutex_lock(&chip->lock);
+
+ if (test_bit(FLAG_REQUESTED, &desc->flags) &&
+ !test_bit(FLAG_IS_OUT, &desc->flags)) {
+ curr = __gpio_mockup_get(chip, offset);
+ if (curr == value)
+ goto out;
+
+ irq = irq_find_mapping(chip->irq_sim_domain, offset);
+ if (!irq)
+ /*
+ * This is fine - it just means, nobody is listening
+ * for interrupts on this line, otherwise
+ * irq_create_mapping() would have been called from
+ * the to_irq() callback.
+ */
+ goto set_value;
+
+ irq_type = irq_get_trigger_type(irq);
+
+ if ((value == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
+ (value == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING))) {
+ ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING,
+ true);
+ if (ret)
+ goto out;
+ }
+ }
+
+set_value:
+ /* Change the value unless we're actively driving the line. */
+ if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
+ !test_bit(FLAG_IS_OUT, &desc->flags))
+ __gpio_mockup_set(chip, offset, value);
+
+out:
+ chip->lines[offset].pull = value;
+ mutex_unlock(&chip->lock);
+ return ret;
+}
+
+static int gpio_mockup_set_config(struct gpio_chip *gc,
+ unsigned int offset, unsigned long config)
+{
+ struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+ switch (pinconf_to_config_param(config)) {
+ case PIN_CONFIG_BIAS_PULL_UP:
+ return gpio_mockup_apply_pull(chip, offset, 1);
+ case PIN_CONFIG_BIAS_PULL_DOWN:
+ return gpio_mockup_apply_pull(chip, offset, 0);
+ default:
+ break;
+ }
+ return -ENOTSUPP;
+}
+
+static int gpio_mockup_dirout(struct gpio_chip *gc,
+ unsigned int offset, int value)
+{
+ struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+ mutex_lock(&chip->lock);
+ chip->lines[offset].dir = GPIO_LINE_DIRECTION_OUT;
+ __gpio_mockup_set(chip, offset, value);
+ mutex_unlock(&chip->lock);
+
+ return 0;
+}
+
+static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
+{
+ struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+ mutex_lock(&chip->lock);
+ chip->lines[offset].dir = GPIO_LINE_DIRECTION_IN;
+ mutex_unlock(&chip->lock);
+
+ return 0;
+}
+
+static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+ struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+ int direction;
+
+ mutex_lock(&chip->lock);
+ direction = chip->lines[offset].dir;
+ mutex_unlock(&chip->lock);
+
+ return direction;
+}
+
+static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
+{
+ struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+ return irq_create_mapping(chip->irq_sim_domain, offset);
+}
+
+static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset)
+{
+ struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+ __gpio_mockup_set(chip, offset, chip->lines[offset].pull);
+}
+
+static ssize_t gpio_mockup_debugfs_read(struct file *file,
+ 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_chip *gc;
+ int val, cnt;
+ char buf[3];
+
+ if (*ppos != 0)
+ return 0;
+
+ sfile = file->private_data;
+ priv = sfile->private;
+ chip = priv->chip;
+ gc = &chip->gc;
+
+ val = gpio_mockup_get(gc, priv->offset);
+ cnt = snprintf(buf, sizeof(buf), "%d\n", val);
+
+ return simple_read_from_buffer(usr_buf, size, ppos, buf, cnt);
+}
+
+static ssize_t gpio_mockup_debugfs_write(struct file *file,
+ const char __user *usr_buf,
+ size_t size, loff_t *ppos)
+{
+ struct gpio_mockup_dbgfs_private *priv;
+ int rv, val;
+ struct seq_file *sfile;
+
+ if (*ppos != 0)
+ return -EINVAL;
+
+ 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;
+ rv = gpio_mockup_apply_pull(priv->chip, priv->offset, val);
+ if (rv)
+ return rv;
+
+ return size;
+}
+
+static int gpio_mockup_debugfs_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, NULL, inode->i_private);
+}
+
+/*
+ * Each mockup chip is represented by a directory named after the chip's device
+ * name under /sys/kernel/debug/gpio-mockup/. Each line is represented by
+ * a file using the line's offset as the name under the chip's directory.
+ *
+ * Reading from the line's file yields the current *value*, writing to the
+ * line's file changes the current *pull*. Default pull for mockup lines is
+ * down.
+ *
+ * Examples:
+ * - when a line pulled down is requested in output mode and driven high, its
+ * value will return to 0 once it's released
+ * - when the line is requested in output mode and driven high, writing 0 to
+ * the corresponding debugfs file will change the pull to down but the
+ * reported value will still be 1 until the line is released
+ * - line requested in input mode always reports the same value as its pull
+ * configuration
+ * - when the line is requested in input mode and monitored for events, writing
+ * the same value to the debugfs file will be a noop, while writing the
+ * opposite value will generate a dummy interrupt with an appropriate edge
+ */
+static const struct file_operations gpio_mockup_debugfs_ops = {
+ .owner = THIS_MODULE,
+ .open = gpio_mockup_debugfs_open,
+ .read = gpio_mockup_debugfs_read,
+ .write = gpio_mockup_debugfs_write,
+ .llseek = no_llseek,
+ .release = single_release,
+};
+
+static void gpio_mockup_debugfs_setup(struct device *dev,
+ struct gpio_mockup_chip *chip)
+{
+ struct gpio_mockup_dbgfs_private *priv;
+ 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);
+
+ for (i = 0; i < gc->ngpio; i++) {
+ name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
+ if (!name)
+ return;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return;
+
+ priv->chip = chip;
+ priv->offset = i;
+ priv->desc = gpiochip_get_desc(gc, i);
+
+ debugfs_create_file(name, 0600, chip->dbg_dir, priv,
+ &gpio_mockup_debugfs_ops);
+ }
+}
+
+static void gpio_mockup_debugfs_cleanup(void *data)
+{
+ struct gpio_mockup_chip *chip = data;
+
+ debugfs_remove_recursive(chip->dbg_dir);
+}
+
+static void gpio_mockup_dispose_mappings(void *data)
+{
+ struct gpio_mockup_chip *chip = data;
+ struct gpio_chip *gc = &chip->gc;
+ int i, irq;
+
+ for (i = 0; i < gc->ngpio; i++) {
+ irq = irq_find_mapping(chip->irq_sim_domain, i);
+ if (irq)
+ irq_dispose_mapping(irq);
+ }
+}
+
+static int gpio_mockup_probe(struct platform_device *pdev)
+{
+ struct gpio_mockup_chip *chip;
+ struct gpio_chip *gc;
+ struct device *dev;
+ const char *name;
+ int rv, base, i;
+ u16 ngpio;
+
+ dev = &pdev->dev;
+
+ rv = device_property_read_u32(dev, "gpio-base", &base);
+ if (rv)
+ base = -1;
+
+ rv = device_property_read_u16(dev, "nr-gpios", &ngpio);
+ if (rv)
+ return rv;
+
+ rv = device_property_read_string(dev, "chip-label", &name);
+ if (rv)
+ name = dev_name(dev);
+
+ chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ mutex_init(&chip->lock);
+
+ 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->get_multiple = gpio_mockup_get_multiple;
+ 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->set_config = gpio_mockup_set_config;
+ gc->to_irq = gpio_mockup_to_irq;
+ gc->free = gpio_mockup_free;
+
+ chip->lines = devm_kcalloc(dev, gc->ngpio,
+ sizeof(*chip->lines), GFP_KERNEL);
+ if (!chip->lines)
+ return -ENOMEM;
+
+ for (i = 0; i < gc->ngpio; i++)
+ chip->lines[i].dir = GPIO_LINE_DIRECTION_IN;
+
+ chip->irq_sim_domain = devm_irq_domain_create_sim(dev, NULL,
+ gc->ngpio);
+ if (IS_ERR(chip->irq_sim_domain))
+ return PTR_ERR(chip->irq_sim_domain);
+
+ rv = devm_add_action_or_reset(dev, gpio_mockup_dispose_mappings, chip);
+ if (rv)
+ return rv;
+
+ rv = devm_gpiochip_add_data(dev, &chip->gc, chip);
+ if (rv)
+ return rv;
+
+ gpio_mockup_debugfs_setup(dev, chip);
+
+ return devm_add_action_or_reset(dev, gpio_mockup_debugfs_cleanup, chip);
+}
+
+static const struct of_device_id gpio_mockup_of_match[] = {
+ { .compatible = "gpio-mockup", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, gpio_mockup_of_match);
+
+static struct platform_driver gpio_mockup_driver = {
+ .driver = {
+ .name = "gpio-mockup",
+ .of_match_table = gpio_mockup_of_match,
+ },
+ .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;
+ struct fwnode_handle *fwnode;
+ int i;
+
+ for (i = 0; i < GPIO_MOCKUP_MAX_GC; i++) {
+ pdev = gpio_mockup_pdevs[i];
+ if (!pdev)
+ continue;
+
+ fwnode = dev_fwnode(&pdev->dev);
+ platform_device_unregister(pdev);
+ fwnode_remove_software_node(fwnode);
+ }
+}
+
+static int __init gpio_mockup_register_chip(int idx)
+{
+ struct property_entry properties[GPIO_MOCKUP_MAX_PROP];
+ struct platform_device_info pdevinfo;
+ struct platform_device *pdev;
+ struct fwnode_handle *fwnode;
+ char **line_names = NULL;
+ char chip_label[32];
+ int prop = 0, base;
+ u16 ngpio;
+
+ memset(properties, 0, sizeof(properties));
+ memset(&pdevinfo, 0, sizeof(pdevinfo));
+
+ snprintf(chip_label, sizeof(chip_label), "gpio-mockup-%c", idx + 'A');
+ properties[prop++] = PROPERTY_ENTRY_STRING("chip-label", chip_label);
+
+ base = gpio_mockup_range_base(idx);
+ if (base >= 0)
+ properties[prop++] = PROPERTY_ENTRY_U32("gpio-base", base);
+
+ ngpio = base < 0 ? gpio_mockup_range_ngpio(idx)
+ : gpio_mockup_range_ngpio(idx) - base;
+ properties[prop++] = PROPERTY_ENTRY_U16("nr-gpios", ngpio);
+
+ if (gpio_mockup_named_lines) {
+ line_names = kasprintf_strarray(GFP_KERNEL, chip_label, ngpio);
+ if (!line_names)
+ return -ENOMEM;
+
+ properties[prop++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
+ "gpio-line-names", line_names, ngpio);
+ }
+
+ fwnode = fwnode_create_software_node(properties, NULL);
+ if (IS_ERR(fwnode)) {
+ kfree_strarray(line_names, ngpio);
+ return PTR_ERR(fwnode);
+ }
+
+ pdevinfo.name = "gpio-mockup";
+ pdevinfo.id = idx;
+ pdevinfo.fwnode = fwnode;
+
+ pdev = platform_device_register_full(&pdevinfo);
+ kfree_strarray(line_names, ngpio);
+ if (IS_ERR(pdev)) {
+ fwnode_remove_software_node(fwnode);
+ pr_err("error registering device");
+ return PTR_ERR(pdev);
+ }
+
+ gpio_mockup_pdevs[idx] = pdev;
+
+ return 0;
+}
+
+static int __init gpio_mockup_init(void)
+{
+ int i, num_chips, err;
+
+ if ((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", NULL);
+
+ err = platform_driver_register(&gpio_mockup_driver);
+ if (err) {
+ pr_err("error registering platform driver\n");
+ debugfs_remove_recursive(gpio_mockup_dbg_dir);
+ return err;
+ }
+
+ for (i = 0; i < num_chips; i++) {
+ err = gpio_mockup_register_chip(i);
+ if (err) {
+ platform_driver_unregister(&gpio_mockup_driver);
+ gpio_mockup_unregister_pdevs();
+ debugfs_remove_recursive(gpio_mockup_dbg_dir);
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+static void __exit gpio_mockup_exit(void)
+{
+ gpio_mockup_unregister_pdevs();
+ debugfs_remove_recursive(gpio_mockup_dbg_dir);
+ platform_driver_unregister(&gpio_mockup_driver);
+}
+
+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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 08:43:19 +0000