[PATCH] Fix regression on spi-fsl-spi.c following modification on spi.c

From: Christophe Leroy
Date: Sun Jun 09 2013 - 05:30:58 EST


spi-fsl-spi.c made the assumption that t->bits_per_word and t->speed_hz were
set only when wanting to change the setting.
Since commit e6811d1d7a6a38ee637fe219c3b67dbfe17e8b3f, t->bits_per_word has
been set in all transfers, therefore the assumption made by the driver leads to
failure. This patch fixes the issue by comparing the t->new bits_per_word and
t->speed_hz with the previous one in order to determine if one of them changed.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>

--- linux-3.8.13/drivers/spi/spi-fsl-spi.c 2013-05-11 22:57:46.000000000 +0200
+++ linux/drivers/spi/spi-fsl-spi.c 2013-06-09 00:13:30.000000000 +0200
@@ -476,11 +476,14 @@
unsigned int cs_change;
const int nsecs = 50;
int status;
+ u32 prev_speed_hz = 0;
+ u8 prev_bits_per_word = 0;

cs_change = 1;
status = 0;
list_for_each_entry(t, &m->transfers, transfer_list) {
- if (t->bits_per_word || t->speed_hz) {
+ if (prev_bits_per_word != t->bits_per_word
+ || prev_speed_hz != t->speed_hz) {
/* Don't allow changes if CS is active */
status = -EINVAL;

@@ -488,6 +491,8 @@
status = fsl_spi_setup_transfer(spi, t);
if (status < 0)
break;
+ prev_bits_per_word = t->bits_per_word;
+ prev_speed_hz = t->speed_hz;
}

if (cs_change) {
--
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