[PATCH 1/7] driver: introduce less error-prone dev_get_drvdata alternative

Sascha Hauer s.hauer at pengutronix.de
Tue Sep 29 02:45:38 EDT 2020


On Mon, Sep 28, 2020 at 05:42:41PM +0200, Ahmad Fatoum wrote:
> We use dev_get_drvdata to get the driver match data associated with a
> device. This has two shortcomings:
> 
>  - Linux has dev_get_drvdata too, which returns a private pointer for
>    driver specific info to associate with a device. We use dev->priv
>    (or more often container_of) for that in barebox instead
> 
>  - It nearly always involves a cast to a double pointer, which is
>    error-prone as size and alignment match need to be ensured
>    on the programmer's part and can easily be gotten wrong:
> 	enum dev_type type
> 	dev_get_drvdata(dev, (const void **)&type);
> 
> Add a new function that instead of using a double pointer argument,
> returns the pointer directly:
> 
>  - For normal pointer driver data, no cast is necessary
>  - For integer driver data casted to a pointer for storage,
>    the cast is still necessary, but

but what?

Sascha


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