mcp23s08 spi gpio expander support

Basic driver for 8-bit SPI based MCP23S08 GPIO expander, without support for
IRQs or the shared chipselect mechanism.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Eric Miao <eric.miao@marvell.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/include/linux/spi/mcp23s08.h b/include/linux/spi/mcp23s08.h
new file mode 100644
index 0000000000..835ddf47d4
--- /dev/null
+++ b/include/linux/spi/mcp23s08.h
@@ -0,0 +1,24 @@
+
+/* FIXME driver should be able to handle all four slaves that
+ * can be hooked up to each chipselect, as well as IRQs...
+ */
+
+struct mcp23s08_platform_data {
+        /* four slaves can share one SPI chipselect */
+        u8              slave;
+
+        /* number assigned to the first GPIO */
+        unsigned        base;
+
+        /* pins with pullups */
+        u8              pullups;
+
+        void            *context;       /* param to setup/teardown */
+
+        int             (*setup)(struct spi_device *spi,
+                                        int gpio, unsigned ngpio,
+                                        void *context);
+        int             (*teardown)(struct spi_device *spi,
+                                        int gpio, unsigned ngpio,
+                                        void *context);
+};