On 16/09/2022 14:07, 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.
>
> The wait-pin allocation is now tracked by the gpmc driver in order
> to be sure that the wait pin has been indeed requested by gpmc.
> Therefore the "wait_pin_alloc_mask" has been introduced.
>
> Signed-off-by: Benedikt Niedermayr <benedikt.niedermayr@xxxxxxxxxxx>
> ---
> drivers/memory/omap-gpmc.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
> index d9bf1c2ac319..ea495e93766b 100644
> --- a/drivers/memory/omap-gpmc.c
> +++ b/drivers/memory/omap-gpmc.c
> @@ -232,6 +232,7 @@ struct gpmc_device {
> int irq;
> struct irq_chip irq_chip;
> struct gpio_chip gpio_chip;
> + unsigned long wait_pin_alloc_mask;
> int nirqs;
> struct resource *data;
> };
> @@ -2221,9 +2222,16 @@ 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 &&
> + test_bit(wait_pin, &gpmc->wait_pin_alloc_mask)) {
> + dev_info(&pdev->dev, "shared wait-pin: %d\n", wait_pin);
> + } else {
> + dev_err(&pdev->dev, "invalid wait-pin: %d\n", wait_pin);
> + goto err;
> + }
> + } else {
> + set_bit(wait_pin, &gpmc->wait_pin_alloc_mask);
> }
And how do you handle shared pin when the original owner unbinds?
Best regards,
Krzysztof
