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Subject[PATCH 21/23] gpio: mockup: provide a way to delete dummy chips
Date
From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Add a new debugfs attribute 'delete_device' to which the chip label can
be written to dynamically remove the associated dummy device.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
drivers/gpio/gpio-mockup.c | 70 +++++++++++++++++++++++++++++++++++++-
1 file changed, 69 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index 1353239dc315..9d2de78a45c2 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -19,6 +19,7 @@
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/slab.h>
+#include <linux/string.h>
#include <linux/string_helpers.h>
#include <linux/uaccess.h>

@@ -668,14 +669,81 @@ static int __init gpio_mockup_register_chips_from_params(void)
return 0;
}

-static int __init gpio_mockup_init(void)
+static ssize_t gpio_mockup_debugfs_delete_device_write(struct file *file,
+ const char __user *usr_buf,
+ size_t size, loff_t *ppos)
{
+ struct gpio_mockup_device *mockup_dev;
+ char label[GPIO_MOCKUP_LABEL_SIZE];
+ struct list_head *curr;
+ struct device *dev;
+ const char *prop;
int ret;

+ if (*ppos != 0)
+ return -EINVAL;
+
+ ret = getline_from_user(label, sizeof(label), usr_buf, size);
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&gpio_mockup_devices_lock);
+
+ list_for_each(curr, &gpio_mockup_devices) {
+ mockup_dev = list_entry(curr, struct gpio_mockup_device, list);
+ dev = &mockup_dev->pdev->dev;
+
+ ret = device_property_read_string(dev, "chip-label", &prop);
+ if (ret) {
+ mutex_unlock(&gpio_mockup_devices_lock);
+ return ret;
+ }
+
+ if (sysfs_streq(label, prop)) {
+ gpio_mockup_unregister_one_device(mockup_dev);
+ mutex_unlock(&gpio_mockup_devices_lock);
+ return size;
+ }
+ }
+
+ mutex_unlock(&gpio_mockup_devices_lock);
+ return -ENODEV;
+}
+
+static const struct file_operations gpio_mockup_debugfs_delete_device_ops = {
+ .owner = THIS_MODULE,
+ .open = gpio_mockup_debugfs_open,
+ .write = gpio_mockup_debugfs_delete_device_write,
+ .llseek = no_llseek,
+ .release = single_release,
+};
+
+static int __init gpio_mockup_debugfs_init(void)
+{
+ struct dentry *entry;
+
gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup", NULL);
if (IS_ERR(gpio_mockup_dbg_dir))
return PTR_ERR(gpio_mockup_dbg_dir);

+ entry = debugfs_create_file("delete_device", 0200, gpio_mockup_dbg_dir,
+ NULL, &gpio_mockup_debugfs_delete_device_ops);
+ if (IS_ERR(entry)) {
+ debugfs_remove_recursive(gpio_mockup_dbg_dir);
+ return PTR_ERR(entry);
+ }
+
+ return 0;
+}
+
+static int __init gpio_mockup_init(void)
+{
+ int ret;
+
+ ret = gpio_mockup_debugfs_init();
+ if (ret)
+ return ret;
+
ret = platform_driver_register(&gpio_mockup_driver);
if (ret) {
pr_err("error registering platform driver\n");
--
2.26.1
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