Re: [PATCH v1.1 3/3] device property: fwnode_property_read_string_array() returns nr of strings

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Wed, Mar 15, 2017 at 03:31:28PM +0200, Sakari Ailus wrote:
> Functionally fwnode_property_read_string_array() should match
> of_property_read_string_array() and work as a drop-in substitute for the
> latter. of_property_read_string_array() returns the number of strings read
> if the target string pointer array is non-NULL. Make
> fwnode_property_read_string_array() do the same.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
> This patch replaces v1 3/3 patch in this set.
> 
> Instead of changing the return value of fwnode / device property API
> string array access on OF, change the behaviour on pset and ACPI instead.
> This makes them to return the number of strings read on success.
> 
> I can merge this with patch 2/3 which is changing the same part of the
> file, however I'm sending this separately at least for now as I think it's
> easier to review this way, rather than making a bugfix and a change of the
> behaviour in the same patch.
> 
> Regards,
> Sakari
> 
>  drivers/base/property.c | 64 +++++++++++++++++++++++++++++++++++--------------
>  1 file changed, 46 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/base/property.c b/drivers/base/property.c
> index 8c98390..82187ac 100644
> --- a/drivers/base/property.c
> +++ b/drivers/base/property.c
> @@ -340,8 +340,8 @@ EXPORT_SYMBOL_GPL(device_property_read_u64_array);
>   * Function reads an array of string properties with @propname from the device
>   * firmware description and stores them to @val if found.
>   *
> - * Return: number of values if @val was %NULL,
> - *         %0 if the property was found (success),
> + * Return: number of values read on success if @val is non-NULL,
> + *	   number of values available on success if @val is NULL,
>   *	   %-EINVAL if given arguments are not valid,
>   *	   %-ENODATA if the property does not have a value,
>   *	   %-EPROTO or %-EILSEQ if the property is not an array of strings,
> @@ -549,29 +549,57 @@ static int __fwnode_property_read_string_array(struct fwnode_handle *fwnode,
>  			of_property_read_string_array(to_of_node(fwnode),
>  						      propname, val, nval) :
>  			of_property_count_strings(to_of_node(fwnode), propname);
> -	else if (is_acpi_node(fwnode))
> -		return acpi_node_prop_read(fwnode, propname, DEV_PROP_STRING,
> -					   val, nval);
> -	else if (is_pset_node(fwnode)) {
> +	else if (is_acpi_node(fwnode)) {
> +		int array_len =
> +			acpi_node_prop_read(fwnode, propname, DEV_PROP_STRING,

Why not change acpi_node_prop_read() instead? This way you don't need to
add the extra code dealing with the return value here.

Ditto for the pset counterpart.