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authormb <mb@3c298f89-4303-0410-b956-a3cf2f4a3e73>2009-02-11 18:02:59 +0000
committermb <mb@3c298f89-4303-0410-b956-a3cf2f4a3e73>2009-02-11 18:02:59 +0000
commitdf128b7feabfe9bf587f18fde89ea35427546b58 (patch)
tree4e22965116e19c81419c09755a8170268967f86b /target/linux
parent8b2a65b25d5c933955844b8958188d3497ea3226 (diff)
spi-gpio: Support busses without chipselect (only one device on the bus)
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@14476 3c298f89-4303-0410-b956-a3cf2f4a3e73
Diffstat (limited to 'target/linux')
-rw-r--r--target/linux/generic-2.6/patches-2.6.28/920-02-spi-gpio-without-cs.patch77
1 files changed, 77 insertions, 0 deletions
diff --git a/target/linux/generic-2.6/patches-2.6.28/920-02-spi-gpio-without-cs.patch b/target/linux/generic-2.6/patches-2.6.28/920-02-spi-gpio-without-cs.patch
new file mode 100644
index 000000000..a67ec5953
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.28/920-02-spi-gpio-without-cs.patch
@@ -0,0 +1,77 @@
+Optionally omit the CS signal, if there's only one device on the bus.
+
+--mb
+
+
+
+Index: linux-2.6.28.2/drivers/spi/spi_gpio.c
+===================================================================
+--- linux-2.6.28.2.orig/drivers/spi/spi_gpio.c 2009-02-11 18:48:23.000000000 +0100
++++ linux-2.6.28.2/drivers/spi/spi_gpio.c 2009-02-11 18:48:50.000000000 +0100
+@@ -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);
+ }
+
+Index: linux-2.6.28.2/include/linux/spi/spi_gpio.h
+===================================================================
+--- linux-2.6.28.2.orig/include/linux/spi/spi_gpio.h 2009-02-11 18:48:23.000000000 +0100
++++ linux-2.6.28.2/include/linux/spi/spi_gpio.h 2009-02-11 18:58:31.000000000 +0100
+@@ -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