[PATCH RFT] spi: dw: Fix off-by-one for checking fifo depth

[Axel Lin <axel.lin-8E1dMatC8ynQT0dZR+AlfA@public.gmane.org>]

The fifo depth could be from 2 to 256 from HW spec, so fix off-by-one for
checking fifo depth.
Without this patch, fifo is 258 after for loop iteration for the "no-match"
case. So below line does not catch the "no-match" case.
        dws->fifo_len = (fifo == 257) ? 0 : fifo;

Signed-off-by: Axel Lin <axel.lin-8E1dMatC8ynQT0dZR+AlfA@public.gmane.org>
---
Hi,
I don't have this hardware handy, so please test it.

BTW, I'm wondering if it make sense to set dws->fifo_len to 0.
Isn't it suppose to be 2 ~ 256?

Thanks.
 drivers/spi/spi-dw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
index d0d5542..74b27479 100644
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -621,7 +621,7 @@ static void spi_hw_init(struct dw_spi *dws)
 	if (!dws->fifo_len) {
 		u32 fifo;
 
-		for (fifo = 2; fifo <= 257; fifo++) {
+		for (fifo = 2; fifo <= 256; fifo++) {
 			dw_writew(dws, DW_SPI_TXFLTR, fifo);
 			if (fifo != dw_readw(dws, DW_SPI_TXFLTR))
 				break;
-- 
1.9.1



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