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spi: pxa2xx: Add ready signal

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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@v3.sk>
Tested-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Lubomir Rintel 2018-11-13 11:22:27 +01:00 committed by Mark Brown
parent 8ae13d0b0d
commit 77d33897c6
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
2 changed files with 18 additions and 1 deletions
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16
drivers/spi/spi-pxa2xx.c
View File

@ -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);

3
drivers/spi/spi-pxa2xx.h
View File

@ -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 {