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From d1d81802522ade84128a2c66c0d500e372474dca Mon Sep 17 00:00:00 2001
From: Torsten Fleischer <torfl6749@gmail.com>
Date: Mon, 3 Nov 2014 17:17:55 +0100
Subject: [PATCH] spi: spi-gpio: Add dt support for a single device with no
chip select
In order to describe a single slave device that has no chip select line
the 'num-chipselects' property has to be <0> and the 'cs-gpios' property
doesn't need to be set.
Signed-off-by: Torsten Fleischer <torfl6749@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
Documentation/devicetree/bindings/spi/spi-gpio.txt | 6 ++++--
drivers/spi/spi-gpio.c | 21 +++++++++++++++------
2 files changed, 19 insertions(+), 8 deletions(-)
--- a/Documentation/devicetree/bindings/spi/spi-gpio.txt
+++ b/Documentation/devicetree/bindings/spi/spi-gpio.txt
@@ -8,8 +8,10 @@ Required properties:
- gpio-sck: GPIO spec for the SCK line to use
- gpio-miso: GPIO spec for the MISO line to use
- gpio-mosi: GPIO spec for the MOSI line to use
- - cs-gpios: GPIOs to use for chipselect lines
- - num-chipselects: number of chipselect lines
+ - cs-gpios: GPIOs to use for chipselect lines.
+ Not needed if num-chipselects = <0>.
+ - num-chipselects: Number of chipselect lines. Should be <0> if a single device
+ with no chip select is connected.
Example:
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -425,6 +425,7 @@ static int spi_gpio_probe(struct platfor
struct spi_gpio_platform_data *pdata;
u16 master_flags = 0;
bool use_of = 0;
+ int num_devices;
status = spi_gpio_probe_dt(pdev);
if (status < 0)
@@ -434,16 +435,21 @@ static int spi_gpio_probe(struct platfor
pdata = dev_get_platdata(&pdev->dev);
#ifdef GENERIC_BITBANG
- if (!pdata || !pdata->num_chipselect)
+ if (!pdata || (!use_of && !pdata->num_chipselect))
return -ENODEV;
#endif
+ if (use_of && !SPI_N_CHIPSEL)
+ num_devices = 1;
+ else
+ num_devices = SPI_N_CHIPSEL;
+
status = spi_gpio_request(pdata, dev_name(&pdev->dev), &master_flags);
if (status < 0)
return status;
master = spi_alloc_master(&pdev->dev, sizeof(*spi_gpio) +
- (sizeof(int) * SPI_N_CHIPSEL));
+ (sizeof(int) * num_devices));
if (!master) {
status = -ENOMEM;
goto gpio_free;
@@ -458,7 +464,7 @@ static int spi_gpio_probe(struct platfor
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
master->flags = master_flags;
master->bus_num = pdev->id;
- master->num_chipselect = SPI_N_CHIPSEL;
+ master->num_chipselect = num_devices;
master->setup = spi_gpio_setup;
master->cleanup = spi_gpio_cleanup;
#ifdef CONFIG_OF
@@ -473,9 +479,12 @@ static int spi_gpio_probe(struct platfor
* property of the node.
*/
- for (i = 0; i < SPI_N_CHIPSEL; i++)
- spi_gpio->cs_gpios[i] =
- of_get_named_gpio(np, "cs-gpios", i);
+ if (!SPI_N_CHIPSEL)
+ spi_gpio->cs_gpios[0] = SPI_GPIO_NO_CHIPSELECT;
+ else
+ for (i = 0; i < SPI_N_CHIPSEL; i++)
+ spi_gpio->cs_gpios[i] =
+ of_get_named_gpio(np, "cs-gpios", i);
}
#endif
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