Re: [PATCH v4 3/4] usb: typec: ucsi: Enable debugfs for message_out data structure

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Tue, Sep 09, 2025 at 06:52:06PM -0700, Pooja Katiyar wrote:
> Add debugfs entry for writing message_out data structure to handle
> UCSI 2.1 and 3.0 commands through debugfs interface.
> 
> Users writing to the message_out debugfs file should ensure the input
> data adheres to the following format:
> 1. Input must be a non-empty valid hexadecimal string.
> 2. Input length of hexadecimal string must not exceed 256 bytes of
>    length to be in alignment with the message out data structure size
>    as per the UCSI specification v2.1.
> 3. If the input string length is odd, then user needs to prepend a
>    '0' to the first character for proper hex conversion.
> 
> Below are examples of valid hex strings. Note that these values are
> just examples. The exact values depend on specific command use case.
> 
>         #echo 1A2B3C4D > message_out
>         #echo 01234567 > message_out
> 
> Signed-off-by: Pooja Katiyar <pooja.katiyar@intel.com>
> ---
> Changelog v4:
> - Fixed build errors reported by kernel test robot.
> - Added changelogs.

Ah, you just copied the same changelog to all patches. You could just
put the log to the cover letter in that case IMO.

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> Changelog v3:
> - Updated debugfs message_out write handler to use message_out fields in
>   UCSI structure.
> 
> Changelog v2:
> - No changes.
> 
>  drivers/usb/typec/ucsi/debugfs.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/usb/typec/ucsi/debugfs.c b/drivers/usb/typec/ucsi/debugfs.c
> index 4bf3a8f65a4e..0693acf04c37 100644
> --- a/drivers/usb/typec/ucsi/debugfs.c
> +++ b/drivers/usb/typec/ucsi/debugfs.c
> @@ -109,6 +109,30 @@ static int ucsi_vbus_volt_show(struct seq_file *m, void *v)
>  }
>  DEFINE_SHOW_ATTRIBUTE(ucsi_vbus_volt);
>  
> +static ssize_t ucsi_message_out_write(struct file *file,
> +				      const char __user *data, size_t count, loff_t *ppos)
> +{
> +	struct ucsi *ucsi = file->private_data;
> +	int ret;
> +
> +	char *buf __free(kfree) = memdup_user_nul(data, count);
> +	if (IS_ERR(buf))
> +		return PTR_ERR(buf);
> +
> +	ucsi->message_out_size = min(count / 2, UCSI_MAX_MESSAGE_OUT_LENGTH);
> +	ret = hex2bin(ucsi->message_out, buf, ucsi->message_out_size);
> +	if (ret)
> +		return ret;
> +
> +	return count;
> +}
> +
> +static const struct file_operations ucsi_message_out_fops = {
> +	.open = simple_open,
> +	.write = ucsi_message_out_write,
> +	.llseek = generic_file_llseek,
> +};
> +
>  void ucsi_debugfs_register(struct ucsi *ucsi)
>  {
>  	ucsi->debugfs = kzalloc(sizeof(*ucsi->debugfs), GFP_KERNEL);
> @@ -121,6 +145,8 @@ void ucsi_debugfs_register(struct ucsi *ucsi)
>  	debugfs_create_file("peak_current", 0400, ucsi->debugfs->dentry, ucsi, &ucsi_peak_curr_fops);
>  	debugfs_create_file("avg_current", 0400, ucsi->debugfs->dentry, ucsi, &ucsi_avg_curr_fops);
>  	debugfs_create_file("vbus_voltage", 0400, ucsi->debugfs->dentry, ucsi, &ucsi_vbus_volt_fops);
> +	debugfs_create_file("message_out", 0200, ucsi->debugfs->dentry, ucsi,
> +			    &ucsi_message_out_fops);
>  }
>  
>  void ucsi_debugfs_unregister(struct ucsi *ucsi)
> -- 
> 2.43.0

-- 
heikki