[PATCH] spi: Dont call master->setup if not populated

[Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

Currently the master->setup() is called unconditionally.
The assumption is that every driver need to implement this
callback. This encourages drivers to populate empty functions
to prevent crashing.

This patch prevents the call of master->setup() if it is not
populated.

Signed-off-by: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
When developing the driver for tegra20 sflash driver, found
that there is notung to do in setup and hence in palce of
adding the empty API, creating this patch.

 drivers/spi/spi.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 6891a03..37a8a2f 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1159,7 +1159,7 @@ EXPORT_SYMBOL_GPL(spi_busnum_to_master);
 int spi_setup(struct spi_device *spi)
 {
 	unsigned	bad_bits;
-	int		status;
+	int		status = 0;
 
 	/* help drivers fail *cleanly* when they need options
 	 * that aren't supported with their current master
@@ -1174,7 +1174,8 @@ int spi_setup(struct spi_device *spi)
 	if (!spi->bits_per_word)
 		spi->bits_per_word = 8;
 
-	status = spi->master->setup(spi);
+	if (spi->master->setup)
+		status = spi->master->setup(spi);
 
 	dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
 				"%u bits/w, %u Hz max --> %d\n",
-- 
1.7.1.1


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