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