If a SPI transfer is set up, but does not explicitly set bits-per-word
and speed_hz, then the transaction fails, because spi_ppc4xx_setupxfer
rejects it.
This patch modifies the logic to chose the struct spi_transfer parameters
only if they are non-zero. Otherwise, the struct spi_device parameters
are used.
Additionally, since there is no OF binding for bits-per-word, we have to
tolerate the case where both t->bits_per_word and spi->bits_per_word are
zero.
---
This was brought to light by a pending patch to spi_bitbang, which results
in more calls to spi_ppc4xx_setupxfer.
drivers/spi/spi_ppc4xx.c | 22 +++++++++++++++-------
1 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/drivers/spi/spi_ppc4xx.c b/drivers/spi/spi_ppc4xx.c
index e46292b..9775bf2 100644
--- a/drivers/spi/spi_ppc4xx.c
+++ b/drivers/spi/spi_ppc4xx.c
@@ -151,16 +151,24 @@ static int spi_ppc4xx_setupxfer(struct spi_device *spi,
struct spi_transfer *t)
/* Write new configration */
out_8(&hw->regs->mode, cs->mode);
+ /* Start with the generic configuration for this device. */
+ bpw = spi->bits_per_word;
+ cs->speed_hz = spi->max_speed_hz;
+
/*
- * Allow platform reduce the interrupt load on the CPU during SPI
- * transfers. We do not target maximum performance, but rather allow
- * platform to limit SPI bus frequency and interrupt rate.
+ * Allow the platform to reduce the interrupt load on the CPU during
+ * SPI transfers. We do not target maximum performance, but rather
+ * allow the platform to limit SPI bus frequency and interrupt rate.
*/
- bpw = t ? t->bits_per_word : spi->bits_per_word;
- cs->speed_hz = t ? min(t->speed_hz, spi->max_speed_hz) :
- spi->max_speed_hz;
+ if(t) {
+ if(t->bits_per_word)
+ bpw = t->bits_per_word;
+
+ if(t->speed_hz)
+ cs->speed_hz = min(t->speed_hz, spi->max_speed_hz);
+ }
- if (bpw != 8) {
+ if (bpw && bpw != 8) {
dev_err(&spi->dev, "invalid bits-per-word (%d)\n", bpw);
return -EINVAL;
}
--
1.6.0.2
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