[3.13.y-ckt stable] Patch "spi: bitbang: Make setup_transfer() callback optional" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    spi: bitbang: Make setup_transfer() callback optional

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt22.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 01d70850e2c3ae34e49a3fbbe756d5a761cc495b Mon Sep 17 00:00:00 2001
From: Pelle Nilsson <per.nilsson at xelmo.com>
Date: Tue, 14 Apr 2015 15:40:17 +0200
Subject: spi: bitbang: Make setup_transfer() callback optional

commit 7d0ec8b6f40b356f780b79de63eeafd6b907d68c upstream.

Some controller drivers have no need of this callback (spi-altera even
causes a NULL pointer dereference because it doesn't register the callback,
falsely assuming that it is already optional).

Fixes: 30af9b558a56 ("spi/bitbang: Drop empty setup() functions")
Signed-off-by: Pelle Nilsson <per.nilsson at xelmo.com>
Reviewed-by: Ezequiel Garcia <ezequiel.garcia at vanguardiasur.com.ar>
Signed-off-by: Mark Brown <broonie at kernel.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/spi/spi-bitbang.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c
index bd222f6..4244415 100644
--- a/drivers/spi/spi-bitbang.c
+++ b/drivers/spi/spi-bitbang.c
@@ -185,7 +185,6 @@ int spi_bitbang_setup(struct spi_device *spi)
 {
 	struct spi_bitbang_cs	*cs = spi->controller_state;
 	struct spi_bitbang	*bitbang;
-	int			retval;
 	unsigned long		flags;

 	bitbang = spi_master_get_devdata(spi->master);
@@ -202,9 +201,11 @@ int spi_bitbang_setup(struct spi_device *spi)
 	if (!cs->txrx_word)
 		return -EINVAL;

-	retval = bitbang->setup_transfer(spi, NULL);
-	if (retval < 0)
-		return retval;
+	if (bitbang->setup_transfer) {
+		int retval = bitbang->setup_transfer(spi, NULL);
+		if (retval < 0)
+			return retval;
+	}

 	dev_dbg(&spi->dev, "%s, %u nsec/bit\n", __func__, 2 * cs->nsecs);

@@ -300,9 +301,11 @@ static int spi_bitbang_transfer_one(struct spi_master *master,

 		/* init (-1) or override (1) transfer params */
 		if (do_setup != 0) {
-			status = bitbang->setup_transfer(spi, t);
-			if (status < 0)
-				break;
+			if (bitbang->setup_transfer) {
+				status = bitbang->setup_transfer(spi, t);
+				if (status < 0)
+					break;
+			}
 			if (do_setup == -1)
 				do_setup = 0;
 		}
--
1.9.1