Re: [PATCH v4 06/11] media: rockchip: rkcif: add driver for mipi csi-2 host

[Mehdi Djait]

Hi Michael,

thank you for the patches.

Sorry for the big delay!

On Wed, Feb 19, 2025 at 11:16:37AM +0100, Michael Riesch wrote:
> The Rockchip RK3568 MIPI CSI-2 Host is a CSI-2 bridge with one input port
> and one output port. It receives the data with the help of an external
> MIPI PHY (C-PHY or D-PHY) and passes it to the Rockchip RK3568 Video
> Capture (VICAP) block. Add a V4L2 subdevice driver for this unit.
> 
> Signed-off-by: Michael Riesch <michael.riesch@xxxxxxxxxxxxxx>
> ---
>  drivers/media/platform/rockchip/rkcif/Makefile     |   1 +
>  .../platform/rockchip/rkcif/rkcif-mipi-csi-host.c  | 731 +++++++++++++++++++++
>  2 files changed, 732 insertions(+)
> 
> diff --git a/drivers/media/platform/rockchip/rkcif/Makefile b/drivers/media/platform/rockchip/rkcif/Makefile
> index 818424972c7b..0c18efd1f1b4 100644
> --- a/drivers/media/platform/rockchip/rkcif/Makefile
> +++ b/drivers/media/platform/rockchip/rkcif/Makefile
> @@ -4,4 +4,5 @@ rockchip-cif-objs += rkcif-dev.o \
>  	rkcif-capture-dvp.o \
>  	rkcif-capture-mipi.o \
>  	rkcif-interface.o \
> +	rkcif-mipi-csi-host.o \

[..]

>  	rkcif-stream.o
> diff --git a/drivers/media/platform/rockchip/rkcif/rkcif-mipi-csi-host.c b/drivers/media/platform/rockchip/rkcif/rkcif-mipi-csi-host.c
> new file mode 100644
> index 000000000000..fa3f42b2dc55

SNIP

> --- /dev/null
> +++ b/drivers/media/platform/rockchip/rkcif/rkcif-mipi-csi-host.c
> +
> +static struct platform_driver rkcif_csi_drv = {
> +	.driver = {
> +		   .name = "rockchip-mipi-csi",
> +		   .of_match_table = rkcif_csi_of_match,
> +		   .pm = &rkcif_csi_pm_ops,
> +	},
> +	.probe = rkcif_csi_probe,
> +	.remove = rkcif_csi_remove,
> +};
> +module_platform_driver(rkcif_csi_drv);

[..]

When adding the driver for this CSI-2 Host bridge, you added another
call to  module_platform_driver()

but in the definition of this macro:

"Each module may only use this macro once, and
calling it replaces module_init() and module_exit()"

and as you can see in the diff of the Makefile,
rkcif-mipi-csi-host.0 is part of the same module as rkcif-dev.o, where
you already call module_platform_driver()

I think the solution here is to call
platform_register_drivers(drivers, ARRAY_SIZE(drivers)) in rkcif-dev.c

with

static struct platform_driver * const drivers[] = {
	&rkcif_csi_drv,
	&rkcif_plat_drv,
};

then define module_init() and module_exit()

Btw. MODULE_DEVICE_TABLE() is missing both here and in rkcif-dev.c

> +
> +MODULE_DESCRIPTION("Rockchip MIPI CSI-2 Host platform driver");
> +MODULE_LICENSE("GPL");
> 
> -- 
> 2.34.1
> 

--
Kind Regards
Mehdi Djait