Re: [PATCH v2] driver: fpga: xilinx-selectmap: add csi and rdwr support

Michal Simek <[email protected]> Wed, 22 Jul 2026 08:55:43 +0200
Newsgroups org.kernel.vger.linux-fpga,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-kernel
Message-ID <[email protected]>

On 7/21/26 13:42, Heiko Schocher wrote:
> Add csi_b and rdwr pin support for the xilinx,selectmap driver.
> 
> In current driver the pins are configured from DTS and set to
> GPIOD_OUT_HIGH. This works in case you have one FPGA.
> 
> Extend this to really implement csi_b and rdwr pin function in
> driver, so it works with more than one FPGA.
> 
> Tested on AM625 based board with 2 FPGAs connected to GPMC.
> 
> Signed-off-by: Heiko Schocher <[email protected]>
> ---
> 
> Changes in v2:
> - add comments from Michal
>    - skip check if gpio descriptor variables csi_b/rdwr_b are valid,
>      as validate_desc() checks this in gpiod_set_value() call.
>    - initialize the gpio variables csi_b/rdwr_b immediately with
>      the return value from devm_gpiod_get_optional(), so we can
>      drop local gpio variable at all
> 
>   drivers/fpga/xilinx-selectmap.c | 23 ++++++++++++++++-------
>   1 file changed, 16 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/fpga/xilinx-selectmap.c b/drivers/fpga/xilinx-selectmap.c
> index d0cbb5fdfe3a..d5175f9430e4 100644
> --- a/drivers/fpga/xilinx-selectmap.c
> +++ b/drivers/fpga/xilinx-selectmap.c
> @@ -19,6 +19,8 @@
>   struct xilinx_selectmap_conf {
>   	struct xilinx_fpga_core core;
>   	void __iomem *base;
> +	struct gpio_desc *csi_b;
> +	struct gpio_desc *rdwr_b;
>   };
>   
>   #define to_xilinx_selectmap_conf(obj) \
> @@ -30,16 +32,21 @@ static int xilinx_selectmap_write(struct xilinx_fpga_core *core,
>   	struct xilinx_selectmap_conf *conf = to_xilinx_selectmap_conf(core);
>   	size_t i;
>   
> +	gpiod_set_value(conf->csi_b, GPIOD_OUT_HIGH);
> +	gpiod_set_value(conf->rdwr_b, GPIOD_OUT_HIGH);

I think GPIOD_OUT_HIGH/LOW is wrong in this context.
If you do "git grep gpiod_set_value" you will see that values are 0/1

Thanks,
Michal