Re: [PATCH 2/2] spi: qcom-geni: Use GPIO to notify master of SPI target activity

On 8/6/2026 3:43 PM, Praveen Talari wrote:
> When operating in SPI target mode, the GENI controller relies on an
> external GPIO to notify the SPI master about the target's active state.
> 
> Add support for an optional device GPIO that is asserted when a target
> transfer begins and deasserted when the transfer completes, is aborted,
> or hits a timeout. This allows the target to explicitly signal its
> availability to the master and ensures the GPIO is released in all error
> and completion paths, preventing the master from observing a stale or
> incorrect target-ready indication.
> 
> The GPIO is optional and requested only when target mode is enabled,
> using devm_gpiod_get_index_optional() so targets without this signal
> continue to work unchanged.

if this is an optional for something like showing target readiness,
why it's required ? if not defined, what mechanism makes it work properly ?

Like does it depend on any timing or sync mechanism if not the GPIO way?

> 
> Signed-off-by: Praveen Talari <[email protected]>
> ---
>   drivers/spi/spi-geni-qcom.c | 25 +++++++++++++++++++++++--
>   1 file changed, 23 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c

[...]

> @@ -1116,8 +1129,16 @@ static int spi_geni_probe(struct platform_device *pdev)
>   	init_completion(&mas->rx_reset_done);
>   	spin_lock_init(&mas->lock);
>   
> -	if (spi->target)
> +	if (spi->target) {
>   		spi->target_abort = spi_geni_target_abort;
> +		mas->target_gpio = devm_gpiod_get_index_optional(dev, "device", 0,
> +								 GPIOD_OUT_LOW);
> +		if (IS_ERR(mas->target_gpio)) {
> +			dev_err(dev, "Failed to request GPIO: %ld\n",
> +				PTR_ERR(mas->target_gpio));
> +			mas->target_gpio = NULL;
IIUC, this GPIO is an optional one. if so, please add a comment to let 
go ahead with an error.

Else need to return an error.
> +		}
> +	}
>   
>   	pm_runtime_use_autosuspend(&pdev->dev);
>   	pm_runtime_set_autosuspend_delay(&pdev->dev, 250);
>