When probing gpio-mockup, create a debugfs directory structure that allows the user to inject line events by writing either 0 (falling-edge) or 1 (rising-edge) to debugfs files.
The gpio-mockup-event directory has one sub-directory per chip and a single event file per line. Signed-off-by: Bartosz Golaszewski <[email protected]> --- drivers/gpio/gpio-mockup.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c index cf8b1b2..c5eb530 100644 --- a/drivers/gpio/gpio-mockup.c +++ b/drivers/gpio/gpio-mockup.c @@ -15,6 +15,10 @@ #include <linux/module.h> #include <linux/gpio/driver.h> #include <linux/platform_device.h> +#include <linux/debugfs.h> +#include <linux/uaccess.h> + +#include "gpiolib.h" #define GPIO_NAME "gpio-mockup" #define MAX_GC 10 @@ -37,6 +41,7 @@ struct gpio_pin_status { struct mockup_gpio_controller { struct gpio_chip gc; struct gpio_pin_status *stats; + struct dentry *dbg_dir; }; static int gpio_mockup_ranges[MAX_GC << 1]; @@ -44,6 +49,7 @@ static int gpio_mockup_params_nr; module_param_array(gpio_mockup_ranges, int, &gpio_mockup_params_nr, 0400); static const char pins_name_start = 'A'; +static struct dentry *dbg_dir; static int mockup_gpio_get(struct gpio_chip *gc, unsigned int offset) { @@ -85,6 +91,80 @@ static int mockup_gpio_get_direction(struct gpio_chip *gc, unsigned int offset) return cntr->stats[offset].dir; } +static ssize_t mockup_gpio_event_write(struct file *file, + const char __user *usr_buf, + size_t size, loff_t *ppos) +{ + struct gpio_desc *desc; + struct seq_file *sfile; + int status, val; + char buf; + + sfile = file->private_data; + desc = sfile->private; + + status = copy_from_user(&buf, usr_buf, 1); + if (status) + return status; + + if (buf == '0') + val = 0; + else if (buf == '1') + val = 1; + else + return -EINVAL; + + gpiod_set_value_cansleep(desc, val); + gpiod_inject_event(desc); + + return size; +} + +static int mockup_gpio_event_open(struct inode *inode, struct file *file) +{ + return single_open(file, NULL, inode->i_private); +} + +static const struct file_operations mockup_gpio_event_ops = { + .owner = THIS_MODULE, + .open = mockup_gpio_event_open, + .write = mockup_gpio_event_write, + .llseek = no_llseek, +}; + +static void mockup_gpio_debugfs_setup(struct mockup_gpio_controller *cntr) +{ + struct dentry *evfile; + struct gpio_chip *gc; + struct device *dev; + char *name; + int i; + + gc = &cntr->gc; + dev = &gc->gpiodev->dev; + + cntr->dbg_dir = debugfs_create_dir(gc->label, dbg_dir); + if (!cntr->dbg_dir) + goto err; + + for (i = 0; i < gc->ngpio; i++) { + name = devm_kasprintf(dev, GFP_KERNEL, "%d", i); + if (!name) + goto err; + + evfile = debugfs_create_file(name, 0200, cntr->dbg_dir, + &gc->gpiodev->descs[i], + &mockup_gpio_event_ops); + if (!evfile) + goto err; + } + + return; + +err: + dev_err(dev, "error creating debugfs directory\n"); +} + static int mockup_gpio_add(struct device *dev, struct mockup_gpio_controller *cntr, const char *name, int base, int ngpio) @@ -112,6 +192,9 @@ static int mockup_gpio_add(struct device *dev, if (ret) goto err; + if (dbg_dir) + mockup_gpio_debugfs_setup(cntr); + dev_info(dev, "gpio<%d..%d> add successful!", base, base + ngpio); return 0; err: @@ -182,6 +265,10 @@ static int __init mock_device_init(void) { int err; + dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL); + if (!dbg_dir) + pr_err("%s: error creating debugfs directory\n", GPIO_NAME); + pdev = platform_device_alloc(GPIO_NAME, -1); if (!pdev) return -ENOMEM; @@ -203,6 +290,7 @@ static int __init mock_device_init(void) static void __exit mock_device_exit(void) { + debugfs_remove_recursive(dbg_dir); platform_driver_unregister(&mockup_gpio_driver); platform_device_unregister(pdev); } -- 2.9.3
