SPI100k: Fix 8-bit and RX-only transfers
This change fixes 8-bit transfers and RX-only transfers. The
SPI100k framework requires minimum 16-bit words to be written, so 8-bit
transfers must be shited by 8 bits and sent out as a 16-bit word.
Additionally, receive-only transfers were failing due to the
perceived need to fill the TX buffer with something. This is in
fact not needed.
Signed-off-by: Cory Maccarrone <darkstar6262@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/spi/omap_spi_100k.c b/drivers/spi/omap_spi_100k.c
index 24668b3..9bd1c92 100644
--- a/drivers/spi/omap_spi_100k.c
+++ b/drivers/spi/omap_spi_100k.c
@@ -141,7 +141,12 @@
{
struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
- /* write 16-bit word */
+ /* write 16-bit word, shifting 8-bit data if necessary */
+ if (len <= 8) {
+ data <<= 8;
+ len = 16;
+ }
+
spi100k_enable_clock(master);
writew( data , spi100k->base + SPI_TX_MSB);
@@ -162,6 +167,10 @@
int dataH,dataL;
struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
+ /* Always do at least 16 bits */
+ if (len <= 8)
+ len = 16;
+
spi100k_enable_clock(master);
writew(SPI_CTRL_SEN(0) |
SPI_CTRL_WORD_SIZE(len) |
@@ -214,10 +223,6 @@
c = count;
word_len = cs->word_len;
- /* RX_ONLY mode needs dummy data in TX reg */
- if (xfer->tx_buf == NULL)
- spi100k_write_data(spi->master,word_len, 0);
-
if (word_len <= 8) {
u8 *rx;
const u8 *tx;
@@ -227,9 +232,9 @@
do {
c-=1;
if (xfer->tx_buf != NULL)
- spi100k_write_data(spi->master,word_len, *tx);
+ spi100k_write_data(spi->master, word_len, *tx++);
if (xfer->rx_buf != NULL)
- *rx = spi100k_read_data(spi->master,word_len);
+ *rx++ = spi100k_read_data(spi->master, word_len);
} while(c);
} else if (word_len <= 16) {
u16 *rx;
@@ -380,10 +385,6 @@
if (t->len) {
unsigned count;
- /* RX_ONLY mode needs dummy data in TX reg */
- if (t->tx_buf == NULL)
- spi100k_write_data(spi->master, 8, 0);
-
count = omap1_spi100k_txrx_pio(spi, t);
m->actual_length += count;