Re: [PATCH v1 2/3] of: Add support for reading a s32 from a multi-value property.

From: Heiko Stübner
Date: Tue Aug 16 2016 - 08:10:32 EST


Hi Finley,

Am Dienstag, 16. August 2016, 10:38:58 schrieb Finlye Xiao:
> From: Finley Xiao <finley.xiao@xxxxxxxxxxxxxx>
>
> This patch adds an of_property_read_s32_index() function to allow
> reading a single indexed s32 value from a property containing multiple
> s32 values.
>
> Signed-off-by: Finley Xiao <finley.xiao@xxxxxxxxxxxxxx>

for people reading along, this simply duplicates what of_property_read_s32
already does, only for indexed properties.

But I do have one issue below.

> ---
> drivers/of/base.c | 23 +++++++++++++++++++++++
> include/linux/of.h | 10 ++++++++++
> 2 files changed, 33 insertions(+)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 7792266..346457d 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -1200,6 +1200,29 @@ int of_property_read_u32_index(const struct
> device_node *np, EXPORT_SYMBOL_GPL(of_property_read_u32_index);
>
> /**
> + * of_property_read_s32_index - Find and read a s32 from a multi-value
> property. + *
> + * @np: device node from which the property value is to be read.
> + * @propname: name of the property to be searched.
> + * @index: index of the u32 in the list of values
> + * @out_value: pointer to return value, modified only if no error.
> + *
> + * Search for a property in a device node and read nth 32-bit value from
> + * it. Returns 0 on success, -EINVAL if the property does not exist,
> + * -ENODATA if property does not have a value, and -EOVERFLOW if the
> + * property data isn't large enough.
> + *
> + * The out_value is modified only if a valid s32 value can be decoded.
> + */
> +int of_property_read_s32_index(const struct device_node *np,
> + const char *propname, u32 index, s32 *out_value)
> +{
> + return of_property_read_u32_index(np, propname, index,
> + (u32 *)out_value);
> +}
> +EXPORT_SYMBOL_GPL(of_property_read_s32_index);

I think this could very well live directly in the of.h header below
of_property_read_s32 or so.

As this also only calls the more generic u32 variant, it can be just a static
inline there and does not need to duplicate the whole stub voodoo, as the
of_property_read_u32_index will also generate the -ENOSYS error in the !OF
case.


Heiko