Hi,
On 15/09/2022 12:13, B. Niedermayr wrote:
> From: Benedikt Niedermayr <benedikt.niedermayr@xxxxxxxxxxx>
>
> Newer kernels refuse to probe when using the same wait pin for
> different chipselect regions.
>
> But this may be a usecase when connecting for example FPGA or ASIC
> modules to the gpmc, which only got one wait pin installed.
>
> Signed-off-by: Benedikt Niedermayr <benedikt.niedermayr@xxxxxxxxxxx>
> ---
> drivers/memory/omap-gpmc.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
> index d9bf1c2ac319..e3674a15b934 100644
> --- a/drivers/memory/omap-gpmc.c
> +++ b/drivers/memory/omap-gpmc.c
> @@ -2221,9 +2221,13 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
> GPIO_ACTIVE_HIGH,
> GPIOD_IN);
> if (IS_ERR(waitpin_desc)) {
> - dev_err(&pdev->dev, "invalid wait-pin: %d\n", wait_pin);
> ret = PTR_ERR(waitpin_desc);
> - goto err;
> + if (ret == -EBUSY) {
> + dev_info(&pdev->dev, "shared wait-pin: %d\n", wait_pin);
What if this GPI was taken by someone other than us for wait-pin usage?
e.g. some other device driver for GPI usage?
In that case that GPIO functionality will break if we now start using it for wait-pin usage. Right?
One solution could be keep track if we reserved that pin for wait-pin usage
and if so sharing the wait-pin for wait-pin usage is fine.
> + } else {
> + dev_err(&pdev->dev, "invalid wait-pin: %d\n", wait_pin);
> + goto err;
> + }
> }
> }
>
cheers,
-roger
