On Wed 2018-10-10 19:09:35, Lubomir Rintel wrote:
> Strobe a GPIO line when the slave TX FIFO is filled. This is how the
> Embedded Controller on an OLPC XO-1.75 machine, that happens to be a SPI
> master, learns that it can initiate a transaction.
>
> Signed-off-by: Lubomir Rintel <lkundrak@xxxxx>
Acked-by: Pavel Machek <pavel@xxxxxx>
> ---
> drivers/spi/spi-pxa2xx.c | 12 ++++++++++++
> drivers/spi/spi-pxa2xx.h | 3 +++
> 2 files changed, 15 insertions(+)
>
> diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
> index 3848842d68fd..a3b4b12c1077 100644
> --- a/drivers/spi/spi-pxa2xx.c
> +++ b/drivers/spi/spi-pxa2xx.c
> @@ -1079,6 +1079,9 @@ static int pxa2xx_spi_transfer_one(struct spi_controller *master,
> if (spi_controller_is_slave(master)) {
> while (drv_data->write(drv_data))
> ;
> + gpiod_set_value(drv_data->gpiod_ready, 1);
> + udelay(1);
> + gpiod_set_value(drv_data->gpiod_ready, 0);
> }
>
> /*
> @@ -1784,6 +1787,15 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
> }
> }
>
> + if (platform_info->is_slave) {
> + drv_data->gpiod_ready = devm_gpiod_get_optional(dev,
> + "ready", GPIOD_OUT_LOW);
> + if (IS_ERR(drv_data->gpiod_ready)) {
> + status = (int)PTR_ERR(drv_data->gpiod_ready);
> + goto out_error_clock_enabled;
> + }
> + }
> +
> pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
> pm_runtime_use_autosuspend(&pdev->dev);
> pm_runtime_set_active(&pdev->dev);
> diff --git a/drivers/spi/spi-pxa2xx.h b/drivers/spi/spi-pxa2xx.h
> index 513c53aaeab2..4e324da66ef7 100644
> --- a/drivers/spi/spi-pxa2xx.h
> +++ b/drivers/spi/spi-pxa2xx.h
> @@ -64,6 +64,9 @@ struct driver_data {
>
> /* GPIOs for chip selects */
> struct gpio_desc **cs_gpiods;
> +
> + /* Optional slave FIFO ready signal */
> + struct gpio_desc *gpiod_ready;
> };
>
> struct chip_data {
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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