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Diffstat (limited to 'target/linux/generic-2.6/patches-2.6.29/920-02-spi-gpio-without-cs.patch')
-rw-r--r--target/linux/generic-2.6/patches-2.6.29/920-02-spi-gpio-without-cs.patch73
1 files changed, 73 insertions, 0 deletions
diff --git a/target/linux/generic-2.6/patches-2.6.29/920-02-spi-gpio-without-cs.patch b/target/linux/generic-2.6/patches-2.6.29/920-02-spi-gpio-without-cs.patch
new file mode 100644
index 0000000000..8b2198ef14
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.29/920-02-spi-gpio-without-cs.patch
@@ -0,0 +1,73 @@
+Optionally omit the CS signal, if there's only one device on the bus.
+
+--mb
+
+
+
+--- a/drivers/spi/spi_gpio.c
++++ b/drivers/spi/spi_gpio.c
+@@ -178,8 +178,10 @@ static void spi_gpio_chipselect(struct s
+ if (is_active)
+ setsck(spi, spi->mode & SPI_CPOL);
+
+- /* SPI is normally active-low */
+- gpio_set_value(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
++ if (cs != SPI_GPIO_NO_CHIPSELECT) {
++ /* SPI is normally active-low */
++ gpio_set_value(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
++ }
+ }
+
+ static int spi_gpio_setup(struct spi_device *spi)
+@@ -191,15 +193,17 @@ static int spi_gpio_setup(struct spi_dev
+ return -EINVAL;
+
+ if (!spi->controller_state) {
+- status = gpio_request(cs, spi->dev.bus_id);
+- if (status)
+- return status;
+- status = gpio_direction_output(cs, spi->mode & SPI_CS_HIGH);
++ if (cs != SPI_GPIO_NO_CHIPSELECT) {
++ status = gpio_request(cs, spi->dev.bus_id);
++ if (status)
++ return status;
++ status = gpio_direction_output(cs, spi->mode & SPI_CS_HIGH);
++ }
+ }
+ if (!status)
+ status = spi_bitbang_setup(spi);
+ if (status) {
+- if (!spi->controller_state)
++ if (!spi->controller_state && cs != SPI_GPIO_NO_CHIPSELECT)
+ gpio_free(cs);
+ }
+ return status;
+@@ -209,7 +213,8 @@ static void spi_gpio_cleanup(struct spi_
+ {
+ unsigned long cs = (unsigned long) spi->controller_data;
+
+- gpio_free(cs);
++ if (cs != SPI_GPIO_NO_CHIPSELECT)
++ gpio_free(cs);
+ spi_bitbang_cleanup(spi);
+ }
+
+--- a/include/linux/spi/spi_gpio.h
++++ b/include/linux/spi/spi_gpio.h
+@@ -25,10 +25,16 @@
+ * ...
+ * };
+ *
++ * If chipselect is not used (there's only one device on the bus), assign
++ * SPI_GPIO_NO_CHIPSELECT to the controller_data:
++ * .controller_data = (void *) SPI_GPIO_NO_CHIPSELECT;
++ *
+ * If the bitbanged bus is later switched to a "native" controller,
+ * that platform_device and controller_data should be removed.
+ */
+
++#define SPI_GPIO_NO_CHIPSELECT ((unsigned long)-1l)
++
+ /**
+ * struct spi_gpio_platform_data - parameter for bitbanged SPI master
+ * @sck: number of the GPIO used for clock output