spi: omap3: add support for more word lengths

Current implementation only supports 8 bit word lengths, even though
omap3 can handle anything between 4 and 32.

Update the spi interface to support changing the SPI word length,
and implement it in omap3_spi driver to support the full range of
possible word lengths.
This implementation is backwards compatible by defaulting to the old
behavior of 8 bit word lengths.
Also, it required a change to the omap3_spi non static I/O functions,
but since they are not used anywhere else, no collateral changes are required.

Cc: Tom Rini <trini@ti.com>
Cc: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index ea39d1a1ee..b76a26cef0 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -8,6 +8,18 @@
 #include <malloc.h>
 #include <spi.h>
 
+int spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen)
+{
+	if (wordlen == 0 || wordlen > 32) {
+		printf("spi: invalid wordlen %d\n", wordlen);
+		return -1;
+	}
+
+	slave->wordlen = wordlen;
+
+	return 0;
+}
+
 void *spi_do_alloc_slave(int offset, int size, unsigned int bus,
 			 unsigned int cs)
 {
@@ -20,6 +32,7 @@ void *spi_do_alloc_slave(int offset, int size, unsigned int bus,
 		slave = (struct spi_slave *)(ptr + offset);
 		slave->bus = bus;
 		slave->cs = cs;
+		slave->wordlen = SPI_DEFAULT_WORDLEN;
 	}
 
 	return ptr;