Orange Pi5 kernel

// 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/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)
{
<------>int curr, irq, irq_type, ret = 0;
<------>struct gpio_desc *desc;
<------>struct gpio_chip *gc;
 
<------>gc = &chip->gc;
<------>desc = &gc->gpiodev->descs[offset];
 
<------>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 = &gc->gpiodev->descs[i];
 
<------><------>debugfs_create_file(name, 0200, chip->dbg_dir, priv,
<------><------><------><------>    &gpio_mockup_debugfs_ops);
<------>}
}
 
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 0;
}
 
static struct platform_driver gpio_mockup_driver = {
<------>.driver = {
<------><------>.name = "gpio-mockup",
<------>},
<------>.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 __init char **gpio_mockup_make_line_names(const char *label,
<------><------><------><------><------><------> unsigned int num_lines)
{
<------>unsigned int i;
<------>char **names;
 
<------>names = kcalloc(num_lines + 1, sizeof(char *), GFP_KERNEL);
<------>if (!names)
<------><------>return NULL;
 
<------>for (i = 0; i < num_lines; i++) {
<------><------>names[i] = kasprintf(GFP_KERNEL, "%s-%u", label, i);
<------><------>if (!names[i]) {
<------><------><------>kfree_strarray(names, i);
<------><------><------>return NULL;
<------><------>}
<------>}
 
<------>return names;
}
 
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;
<------>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 = gpio_mockup_make_line_names(chip_label, ngpio);
<------><------>if (!line_names)
<------><------><------>return -ENOMEM;
 
<------><------>properties[prop++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
<------><------><------><------><------>"gpio-line-names", line_names, ngpio);
<------>}
 
<------>pdevinfo.name = "gpio-mockup";
<------>pdevinfo.id = idx;
<------>pdevinfo.properties = properties;
 
<------>pdev = platform_device_register_full(&pdevinfo);
<------>kfree_strarray(line_names, ngpio);
<------>if (IS_ERR(pdev)) {
<------><------>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 % 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)
{
<------>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");