regmap: Add support for writing to regmap registers via debugfs

To enable writing to the regmap debugfs registers file users will
need to modify the source directly and #define REGMAP_ALLOW_WRITE_DEBUGFS.
The reason for this is that it is dangerous to expose this
functionality in general where clients could potentially be PMICs.

[A couple of minor style updates -- broonie]

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Dimitris Papastamos 2012-02-22 12:43:50 +00:00 committed by Mark Brown
parent b8fb5ab156
commit 09c6ecd394
1 changed files with 42 additions and 0 deletions

View File

@ -103,9 +103,51 @@ out:
return ret;
}
#undef REGMAP_ALLOW_WRITE_DEBUGFS
#ifdef REGMAP_ALLOW_WRITE_DEBUGFS
/*
* This can be dangerous especially when we have clients such as
* PMICs, therefore don't provide any real compile time configuration option
* for this feature, people who want to use this will need to modify
* the source code directly.
*/
static ssize_t regmap_map_write_file(struct file *file,
const char __user *user_buf,
size_t count, loff_t *ppos)
{
char buf[32];
size_t buf_size;
char *start = buf;
unsigned long reg, value;
struct regmap *map = file->private_data;
buf_size = min(count, (sizeof(buf)-1));
if (copy_from_user(buf, user_buf, buf_size))
return -EFAULT;
buf[buf_size] = 0;
while (*start == ' ')
start++;
reg = simple_strtoul(start, &start, 16);
while (*start == ' ')
start++;
if (strict_strtoul(start, 16, &value))
return -EINVAL;
/* Userspace has been fiddling around behind the kernel's back */
add_taint(TAINT_USER);
regmap_write(map, reg, value);
return buf_size;
}
#else
#define regmap_map_write_file NULL
#endif
static const struct file_operations regmap_map_fops = {
.open = regmap_open_file,
.read = regmap_map_read_file,
.write = regmap_map_write_file,
.llseek = default_llseek,
};