![Bartosz Golaszewski](/assets/img/avatar_default.png)
Calling read() for a single byte read will return 2 currently. Use
simple_read_from_buffer() which correctly handles all sizes.
Fixes: 2a9e27408e
("gpio: mockup: rework debugfs interface")
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
564 lines
14 KiB
C
564 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* GPIO Testing Device Driver
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*
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* Copyright (C) 2014 Kamlakant Patel <kamlakant.patel@broadcom.com>
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* Copyright (C) 2015-2016 Bamvor Jian Zhang <bamv2005@gmail.com>
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* Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/gpio/driver.h>
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#include <linux/gpio/consumer.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/irq_sim.h>
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#include <linux/debugfs.h>
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#include <linux/uaccess.h>
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#include <linux/property.h>
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#include "gpiolib.h"
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#define GPIO_MOCKUP_NAME "gpio-mockup"
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#define GPIO_MOCKUP_MAX_GC 10
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/*
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* We're storing two values per chip: the GPIO base and the number
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* of GPIO lines.
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*/
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#define GPIO_MOCKUP_MAX_RANGES (GPIO_MOCKUP_MAX_GC * 2)
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/* Maximum of three properties + the sentinel. */
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#define GPIO_MOCKUP_MAX_PROP 4
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#define gpio_mockup_err(...) pr_err(GPIO_MOCKUP_NAME ": " __VA_ARGS__)
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enum {
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GPIO_MOCKUP_DIR_IN = 0,
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GPIO_MOCKUP_DIR_OUT = 1,
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};
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/*
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* struct gpio_pin_status - structure describing a GPIO status
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* @dir: Configures direction of gpio as "in" or "out", 0=in, 1=out
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* @value: Configures status of the gpio as 0(low) or 1(high)
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*/
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struct gpio_mockup_line_status {
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int dir;
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int value;
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int pull;
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};
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struct gpio_mockup_chip {
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struct gpio_chip gc;
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struct gpio_mockup_line_status *lines;
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struct irq_sim irqsim;
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struct dentry *dbg_dir;
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struct mutex lock;
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};
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struct gpio_mockup_dbgfs_private {
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struct gpio_mockup_chip *chip;
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struct gpio_desc *desc;
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unsigned int offset;
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};
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static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES];
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static int gpio_mockup_num_ranges;
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module_param_array(gpio_mockup_ranges, int, &gpio_mockup_num_ranges, 0400);
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static bool gpio_mockup_named_lines;
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module_param_named(gpio_mockup_named_lines,
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gpio_mockup_named_lines, bool, 0400);
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static struct dentry *gpio_mockup_dbg_dir;
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static int gpio_mockup_range_base(unsigned int index)
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{
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return gpio_mockup_ranges[index * 2];
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}
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static int gpio_mockup_range_ngpio(unsigned int index)
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{
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return gpio_mockup_ranges[index * 2 + 1];
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}
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static int __gpio_mockup_get(struct gpio_mockup_chip *chip,
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unsigned int offset)
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{
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return chip->lines[offset].value;
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}
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static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
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{
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
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int val;
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mutex_lock(&chip->lock);
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val = __gpio_mockup_get(chip, offset);
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mutex_unlock(&chip->lock);
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return val;
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}
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static int gpio_mockup_get_multiple(struct gpio_chip *gc,
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unsigned long *mask, unsigned long *bits)
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{
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
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unsigned int bit, val;
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mutex_lock(&chip->lock);
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for_each_set_bit(bit, mask, gc->ngpio) {
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val = __gpio_mockup_get(chip, bit);
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__assign_bit(bit, bits, val);
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}
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mutex_unlock(&chip->lock);
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return 0;
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}
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static void __gpio_mockup_set(struct gpio_mockup_chip *chip,
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unsigned int offset, int value)
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{
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chip->lines[offset].value = !!value;
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}
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static void gpio_mockup_set(struct gpio_chip *gc,
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unsigned int offset, int value)
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{
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
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mutex_lock(&chip->lock);
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__gpio_mockup_set(chip, offset, value);
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mutex_unlock(&chip->lock);
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}
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static void gpio_mockup_set_multiple(struct gpio_chip *gc,
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unsigned long *mask, unsigned long *bits)
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{
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
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unsigned int bit;
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mutex_lock(&chip->lock);
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for_each_set_bit(bit, mask, gc->ngpio)
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__gpio_mockup_set(chip, bit, test_bit(bit, bits));
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mutex_unlock(&chip->lock);
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}
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static int gpio_mockup_dirout(struct gpio_chip *gc,
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unsigned int offset, int value)
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{
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
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mutex_lock(&chip->lock);
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chip->lines[offset].dir = GPIO_MOCKUP_DIR_OUT;
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__gpio_mockup_set(chip, offset, value);
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mutex_unlock(&chip->lock);
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return 0;
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}
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static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
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{
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
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mutex_lock(&chip->lock);
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chip->lines[offset].dir = GPIO_MOCKUP_DIR_IN;
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mutex_unlock(&chip->lock);
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return 0;
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}
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static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
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{
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
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int direction;
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mutex_lock(&chip->lock);
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direction = !chip->lines[offset].dir;
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mutex_unlock(&chip->lock);
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return direction;
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}
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static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
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{
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
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return irq_sim_irqnum(&chip->irqsim, offset);
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}
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static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset)
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{
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
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__gpio_mockup_set(chip, offset, chip->lines[offset].pull);
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}
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static ssize_t gpio_mockup_debugfs_read(struct file *file,
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char __user *usr_buf,
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size_t size, loff_t *ppos)
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{
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struct gpio_mockup_dbgfs_private *priv;
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struct gpio_mockup_chip *chip;
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struct seq_file *sfile;
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struct gpio_chip *gc;
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int val, cnt;
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char buf[3];
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if (*ppos != 0)
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return 0;
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sfile = file->private_data;
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priv = sfile->private;
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chip = priv->chip;
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gc = &chip->gc;
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val = gpio_mockup_get(gc, priv->offset);
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cnt = snprintf(buf, sizeof(buf), "%d\n", val);
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return simple_read_from_buffer(usr_buf, size, ppos, buf, cnt);
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}
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static ssize_t gpio_mockup_debugfs_write(struct file *file,
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const char __user *usr_buf,
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size_t size, loff_t *ppos)
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{
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struct gpio_mockup_dbgfs_private *priv;
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int rv, val, curr, irq, irq_type;
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struct gpio_mockup_chip *chip;
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struct seq_file *sfile;
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struct gpio_desc *desc;
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struct gpio_chip *gc;
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struct irq_sim *sim;
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if (*ppos != 0)
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return -EINVAL;
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rv = kstrtoint_from_user(usr_buf, size, 0, &val);
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if (rv)
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return rv;
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if (val != 0 && val != 1)
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return -EINVAL;
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sfile = file->private_data;
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priv = sfile->private;
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chip = priv->chip;
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gc = &chip->gc;
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desc = &gc->gpiodev->descs[priv->offset];
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sim = &chip->irqsim;
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mutex_lock(&chip->lock);
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if (test_bit(FLAG_REQUESTED, &desc->flags) &&
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!test_bit(FLAG_IS_OUT, &desc->flags)) {
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curr = __gpio_mockup_get(chip, priv->offset);
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if (curr == val)
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goto out;
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irq = irq_sim_irqnum(sim, priv->offset);
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irq_type = irq_get_trigger_type(irq);
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if ((val == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
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(val == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING)))
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irq_sim_fire(sim, priv->offset);
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}
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/* Change the value unless we're actively driving the line. */
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if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
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!test_bit(FLAG_IS_OUT, &desc->flags))
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__gpio_mockup_set(chip, priv->offset, val);
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out:
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chip->lines[priv->offset].pull = val;
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mutex_unlock(&chip->lock);
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return size;
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}
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static int gpio_mockup_debugfs_open(struct inode *inode, struct file *file)
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{
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return single_open(file, NULL, inode->i_private);
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}
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/*
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* Each mockup chip is represented by a directory named after the chip's device
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* name under /sys/kernel/debug/gpio-mockup/. Each line is represented by
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* a file using the line's offset as the name under the chip's directory.
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*
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* Reading from the line's file yields the current *value*, writing to the
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* line's file changes the current *pull*. Default pull for mockup lines is
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* down.
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*
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* Examples:
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* - when a line pulled down is requested in output mode and driven high, its
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* value will return to 0 once it's released
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* - when the line is requested in output mode and driven high, writing 0 to
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* the corresponding debugfs file will change the pull to down but the
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* reported value will still be 1 until the line is released
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* - line requested in input mode always reports the same value as its pull
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* configuration
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* - when the line is requested in input mode and monitored for events, writing
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* the same value to the debugfs file will be a noop, while writing the
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* opposite value will generate a dummy interrupt with an appropriate edge
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*/
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static const struct file_operations gpio_mockup_debugfs_ops = {
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.owner = THIS_MODULE,
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.open = gpio_mockup_debugfs_open,
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.read = gpio_mockup_debugfs_read,
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.write = gpio_mockup_debugfs_write,
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.llseek = no_llseek,
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};
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static void gpio_mockup_debugfs_setup(struct device *dev,
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struct gpio_mockup_chip *chip)
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{
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struct gpio_mockup_dbgfs_private *priv;
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struct dentry *evfile;
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struct gpio_chip *gc;
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const char *devname;
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char *name;
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int i;
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gc = &chip->gc;
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devname = dev_name(&gc->gpiodev->dev);
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chip->dbg_dir = debugfs_create_dir(devname, gpio_mockup_dbg_dir);
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if (IS_ERR_OR_NULL(chip->dbg_dir))
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goto err;
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for (i = 0; i < gc->ngpio; i++) {
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name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
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if (!name)
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goto err;
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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goto err;
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priv->chip = chip;
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priv->offset = i;
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priv->desc = &gc->gpiodev->descs[i];
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evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv,
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&gpio_mockup_debugfs_ops);
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if (IS_ERR_OR_NULL(evfile))
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goto err;
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}
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return;
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err:
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dev_err(dev, "error creating debugfs files\n");
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}
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static int gpio_mockup_name_lines(struct device *dev,
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struct gpio_mockup_chip *chip)
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{
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struct gpio_chip *gc = &chip->gc;
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char **names;
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int i;
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names = devm_kcalloc(dev, gc->ngpio, sizeof(char *), GFP_KERNEL);
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if (!names)
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return -ENOMEM;
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for (i = 0; i < gc->ngpio; i++) {
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names[i] = devm_kasprintf(dev, GFP_KERNEL,
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"%s-%d", gc->label, i);
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if (!names[i])
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return -ENOMEM;
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}
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gc->names = (const char *const *)names;
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return 0;
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}
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static int gpio_mockup_probe(struct platform_device *pdev)
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{
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struct gpio_mockup_chip *chip;
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struct gpio_chip *gc;
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struct device *dev;
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const char *name;
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int rv, base;
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u16 ngpio;
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dev = &pdev->dev;
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rv = device_property_read_u32(dev, "gpio-base", &base);
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if (rv)
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base = -1;
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rv = device_property_read_u16(dev, "nr-gpios", &ngpio);
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if (rv)
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return rv;
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rv = device_property_read_string(dev, "chip-name", &name);
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if (rv)
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name = NULL;
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chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
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if (!chip)
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return -ENOMEM;
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if (!name) {
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name = devm_kasprintf(dev, GFP_KERNEL,
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"%s-%c", pdev->name, pdev->id + 'A');
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if (!name)
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return -ENOMEM;
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}
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mutex_init(&chip->lock);
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gc = &chip->gc;
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gc->base = base;
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gc->ngpio = ngpio;
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gc->label = name;
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gc->owner = THIS_MODULE;
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gc->parent = dev;
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gc->get = gpio_mockup_get;
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gc->set = gpio_mockup_set;
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gc->get_multiple = gpio_mockup_get_multiple;
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gc->set_multiple = gpio_mockup_set_multiple;
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gc->direction_output = gpio_mockup_dirout;
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gc->direction_input = gpio_mockup_dirin;
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gc->get_direction = gpio_mockup_get_direction;
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gc->to_irq = gpio_mockup_to_irq;
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gc->free = gpio_mockup_free;
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chip->lines = devm_kcalloc(dev, gc->ngpio,
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sizeof(*chip->lines), GFP_KERNEL);
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if (!chip->lines)
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return -ENOMEM;
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if (device_property_read_bool(dev, "named-gpio-lines")) {
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rv = gpio_mockup_name_lines(dev, chip);
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if (rv)
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return rv;
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}
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rv = devm_irq_sim_init(dev, &chip->irqsim, gc->ngpio);
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if (rv < 0)
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return rv;
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rv = devm_gpiochip_add_data(dev, &chip->gc, chip);
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if (rv)
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return rv;
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if (!IS_ERR_OR_NULL(gpio_mockup_dbg_dir))
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gpio_mockup_debugfs_setup(dev, chip);
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return 0;
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}
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static struct platform_driver gpio_mockup_driver = {
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.driver = {
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.name = GPIO_MOCKUP_NAME,
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},
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.probe = gpio_mockup_probe,
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};
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static struct platform_device *gpio_mockup_pdevs[GPIO_MOCKUP_MAX_GC];
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static void gpio_mockup_unregister_pdevs(void)
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{
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struct platform_device *pdev;
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int i;
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for (i = 0; i < GPIO_MOCKUP_MAX_GC; i++) {
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pdev = gpio_mockup_pdevs[i];
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if (pdev)
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platform_device_unregister(pdev);
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}
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}
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static int __init gpio_mockup_init(void)
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{
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struct property_entry properties[GPIO_MOCKUP_MAX_PROP];
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int i, prop, num_chips, err = 0, base;
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struct platform_device_info pdevinfo;
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struct platform_device *pdev;
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u16 ngpio;
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if ((gpio_mockup_num_ranges < 2) ||
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(gpio_mockup_num_ranges % 2) ||
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(gpio_mockup_num_ranges > GPIO_MOCKUP_MAX_RANGES))
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return -EINVAL;
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/* Each chip is described by two values. */
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num_chips = gpio_mockup_num_ranges / 2;
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/*
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* The second value in the <base GPIO - number of GPIOS> pair must
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* always be greater than 0.
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*/
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for (i = 0; i < num_chips; i++) {
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if (gpio_mockup_range_ngpio(i) < 0)
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return -EINVAL;
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}
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gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup", NULL);
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if (IS_ERR_OR_NULL(gpio_mockup_dbg_dir))
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gpio_mockup_err("error creating debugfs directory\n");
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err = platform_driver_register(&gpio_mockup_driver);
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if (err) {
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gpio_mockup_err("error registering platform driver\n");
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return err;
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}
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|
|
|
for (i = 0; i < num_chips; i++) {
|
|
memset(properties, 0, sizeof(properties));
|
|
memset(&pdevinfo, 0, sizeof(pdevinfo));
|
|
prop = 0;
|
|
|
|
base = gpio_mockup_range_base(i);
|
|
if (base >= 0)
|
|
properties[prop++] = PROPERTY_ENTRY_U32("gpio-base",
|
|
base);
|
|
|
|
ngpio = base < 0 ? gpio_mockup_range_ngpio(i)
|
|
: gpio_mockup_range_ngpio(i) - base;
|
|
properties[prop++] = PROPERTY_ENTRY_U16("nr-gpios", ngpio);
|
|
|
|
if (gpio_mockup_named_lines)
|
|
properties[prop++] = PROPERTY_ENTRY_BOOL(
|
|
"named-gpio-lines");
|
|
|
|
pdevinfo.name = GPIO_MOCKUP_NAME;
|
|
pdevinfo.id = i;
|
|
pdevinfo.properties = properties;
|
|
|
|
pdev = platform_device_register_full(&pdevinfo);
|
|
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");
|