Re: [PATCH v14 1/4] drivers pps/generators: replace copy of pps-gen info struct with const pointer
From: Andy Shevchenko
Date: Fri Feb 14 2025 - 09:55:10 EST
On Fri, Feb 14, 2025 at 02:37:52PM +0530, subramanian.mohan@xxxxxxxxx wrote:
> From: Subramanian Mohan <subramanian.mohan@xxxxxxxxx>
>
> Some PPS generator drivers may need to retrieve a pointer to their
> internal data while executing the PPS generator enable() method.
>
> During the driver registration the pps_gen_device pointer is returned
> from the framework, and for that reason, there is difficulty in
> getting generator driver data back in the enable function. We won't be
> able to use container_of macro as it results in static assert, and we
> might end up in using static pointer.
>
> To solve the issue and to get back the generator driver data back, we
> should not copy the struct pps_gen_source_info within the struct
> pps_gen_device during the registration stage, but simply save the
> pointer of the driver one. In this manner, driver may get a pointer
> to their internal data as shown below:
>
> struct pps_gen_foo_data_s {
> ...
> struct pps_gen_source_info gen_info;
> struct pps_gen_device *pps_gen;
> ...
> };
>
> static int __init pps_gen_foo_init(void)
> {
> struct pps_gen_foo_data_s *foo;
> ...
> foo->pps_gen = pps_gen_register_source(&foo->gen_info);
> ...
> }
>
> Then, in the enable() method, we can retrieve the pointer to the main
> struct by using the code below:
>
> static int pps_gen_foo_enable(struct pps_gen_device *pps_gen, bool enable)
> {
> struct pps_gen_foo_data_s *foo = container_of(pps_gen->info,
> struct pps_gen_foo_data_s, gen_info);
> ...
> }
Shouldn't Subject start with "pps: generators: ..."?
With that fixed,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
--
With Best Regards,
Andy Shevchenko