From 77d33897c68d56797a3201e06bdf10e2094a96d6 Mon Sep 17 00:00:00 2001 From: Lubomir Rintel Date: Tue, 13 Nov 2018 11:22:27 +0100 Subject: [PATCH] spi: pxa2xx: Add ready signal 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 Tested-by: Pavel Machek Reviewed-by: Geert Uytterhoeven Signed-off-by: Mark Brown --- drivers/spi/spi-pxa2xx.c | 16 +++++++++++++++- drivers/spi/spi-pxa2xx.h | 3 +++ 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c index a057c3be7e3b..69b221e34b2d 100644 --- a/drivers/spi/spi-pxa2xx.c +++ b/drivers/spi/spi-pxa2xx.c @@ -1081,6 +1081,11 @@ static int pxa2xx_spi_transfer_one(struct spi_controller *master, if (spi_controller_is_slave(master)) { while (drv_data->write(drv_data)) ; + if (drv_data->gpiod_ready) { + gpiod_set_value(drv_data->gpiod_ready, 1); + udelay(1); + gpiod_set_value(drv_data->gpiod_ready, 0); + } } /* @@ -1778,7 +1783,7 @@ static int pxa2xx_spi_probe(struct platform_device *pdev) if (PTR_ERR(gpiod) == -ENOENT) continue; - status = (int)PTR_ERR(gpiod); + status = PTR_ERR(gpiod); goto out_error_clock_enabled; } else { drv_data->cs_gpiods[i] = gpiod; @@ -1786,6 +1791,15 @@ 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 = 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 { -- 2.11.0