From: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Date: Wed, 27 Mar 2019 14:30:51 +0000 (+0000)
Subject: spi: spi-fsl-spi: relax message sanity checking a little
X-Git-Tag: v4.14.322~121
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=379380906bba14c9e2ec68ad01ab9bec1d52dd76;p=thirdparty%2Fkernel%2Fstable.git

spi: spi-fsl-spi: relax message sanity checking a little

commit 17ecffa289489e8442306bbc62ebb964e235cdad upstream.

The comment says that we should not allow changes (to
bits_per_word/speed_hz) while CS is active, and indeed the code below
does fsl_spi_setup_transfer() when the ->cs_change of the previous
spi_transfer was set (and for the very first transfer).

So the sanity checking is a bit too strict - we can change it to
follow the same logic as is used by the actual transfer loop.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/spi/spi-fsl-spi.c b/drivers/spi/spi-fsl-spi.c
index c99fb47d02aed..5eecf399745eb 100644
--- a/drivers/spi/spi-fsl-spi.c
+++ b/drivers/spi/spi-fsl-spi.c
@@ -373,13 +373,15 @@ static int fsl_spi_do_one_msg(struct spi_master *master,
 	}
 
 	/* Don't allow changes if CS is active */
-	first = list_first_entry(&m->transfers, struct spi_transfer,
-			transfer_list);
+	cs_change = 1;
 	list_for_each_entry(t, &m->transfers, transfer_list) {
+		if (cs_change)
+			first = t;
+		cs_change = t->cs_change;
 		if ((first->bits_per_word != t->bits_per_word) ||
 			(first->speed_hz != t->speed_hz)) {
 			dev_err(&spi->dev,
-				"bits_per_word/speed_hz should be same for the same SPI transfer\n");
+				"bits_per_word/speed_hz cannot change while CS is active\n");
 			return -EINVAL;
 		}
 	}