From 98210b7f73f1db182bd9a558a031093cd166e907 Mon Sep 17 00:00:00 2001 From: Arend van Spriel Date: Sun, 9 Nov 2014 11:31:58 +0100 Subject: debugfs: add helper function to create device related seq_file This patch adds a helper function that simplifies adding a so-called single_open sequence file for device drivers. The calling device driver needs to provide a read function and a device pointer. The field struct seq_file::private will reference the device pointer upon call to the read function so the driver can obtain his data from it and do its task of providing the file content using seq_printf() calls and alike. Using this helper function also gets rid of the need to specify file operations per debugfs file. Signed-off-by: Arend van Spriel Signed-off-by: Greg Kroah-Hartman --- fs/debugfs/file.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) (limited to 'fs/debugfs/file.c') diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 76c08c2beb2f..a2f8ec70fe8d 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -22,6 +22,7 @@ #include #include #include +#include static ssize_t default_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) @@ -761,3 +762,56 @@ struct dentry *debugfs_create_regset32(const char *name, umode_t mode, EXPORT_SYMBOL_GPL(debugfs_create_regset32); #endif /* CONFIG_HAS_IOMEM */ + +struct debugfs_devm_entry { + int (*read)(struct seq_file *seq, void *data); + struct device *dev; +}; + +static int debugfs_devm_entry_open(struct inode *inode, struct file *f) +{ + struct debugfs_devm_entry *entry = inode->i_private; + + return single_open(f, entry->read, entry->dev); +} + +static const struct file_operations debugfs_devm_entry_ops = { + .owner = THIS_MODULE, + .open = debugfs_devm_entry_open, + .release = single_release, + .read = seq_read, + .llseek = seq_lseek +}; + +/** + * debugfs_create_devm_seqfile - create a debugfs file that is bound to device. + * + * @dev: device related to this debugfs file. + * @name: name of the debugfs file. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @read_fn: function pointer called to print the seq_file content. + */ +struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name, + struct dentry *parent, + int (*read_fn)(struct seq_file *s, + void *data)) +{ + struct debugfs_devm_entry *entry; + + if (IS_ERR(parent)) + return ERR_PTR(-ENOENT); + + entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL); + if (!entry) + return ERR_PTR(-ENOMEM); + + entry->read = read_fn; + entry->dev = dev; + + return debugfs_create_file(name, S_IRUGO, parent, entry, + &debugfs_devm_entry_ops); +} +EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile); + -- cgit v1.2.3