From b9d228f9e896df1af787b2f3467889ab0832370a Mon Sep 17 00:00:00 2001
From: Matthias Brugger <matthias.bgg@gmail.com>
Date: Wed, 13 Oct 2010 17:51:02 +0200
Subject: [PATCH] spi/atmel: let transfers through if not changing
bits_per_word
bits_per_word option in spi_transfer are allowed if it does not change
the csr register.
This is necessary for the driver in
drivers/staging/iio/adis16260_core.c, as it uses this option.
Signed-off-by: Matthias Brugger <mensch0815@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
drivers/spi/atmel_spi.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index c4e04428992d..5c03a5bb168a 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -654,6 +654,8 @@ static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
struct spi_transfer *xfer;
unsigned long flags;
struct device *controller = spi->master->dev.parent;
+ u8 bits;
+ struct atmel_spi_device *asd;
as = spi_master_get_devdata(spi->master);
@@ -672,8 +674,18 @@ static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
return -EINVAL;
}
+ if (xfer->bits_per_word) {
+ asd = spi->controller_state;
+ bits = (asd->csr >> 4) & 0xf;
+ if (bits != xfer->bits_per_word - 8) {
+ dev_dbg(&spi->dev, "you can't yet change "
+ "bit_per_word in transfers\n");
+ return -ENOPROTOOPT;
+ }
+ }
+
/* FIXME implement these protocol options!! */
- if (xfer->bits_per_word || xfer->speed_hz) {
+ if (xfer->speed_hz) {
dev_dbg(&spi->dev, "no protocol options yet\n");
return -ENOPROTOOPT;
}
--
2.34.1