diff mbox

[v2] spi: bitbang: Make setup_transfer() callback optional

Message ID 1429018817-18117-1-git-send-email-per.nilsson@xelmo.com (mailing list archive)
State Accepted
Commit 7d0ec8b6f40b356f780b79de63eeafd6b907d68c
Headers show

Commit Message

Pelle Nilsson April 14, 2015, 1:40 p.m. UTC
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@xelmo.com>
---
 drivers/spi/spi-bitbang.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

Comments

Ezequiel Garcia April 14, 2015, 3:36 p.m. UTC | #1
On 04/14/2015 10:40 AM, Pelle Nilsson wrote:
> 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@xelmo.com>

Reviewed-by: Ezequiel Garcia <ezequiel.garcia@vanguardiasur.com.ar>

Please note the merge window is open, so don't expect Mark to pick
your change soon.
Mark Brown April 18, 2015, 11 a.m. UTC | #2
On Tue, Apr 14, 2015 at 03:40:17PM +0200, Pelle Nilsson wrote:
> 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).

I've applied this but really for something like this the commit message
should be explaining *why* it's reasonable for the callback to be
omitted.
diff mbox

Patch

diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c
index 5ef6638..840a498 100644
--- a/drivers/spi/spi-bitbang.c
+++ b/drivers/spi/spi-bitbang.c
@@ -180,7 +180,6 @@  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);
@@ -197,9 +196,11 @@  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);
 
@@ -295,9 +296,11 @@  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;
 		}