spi: Dont call master->setup if not populated

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@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 84c2861d6f4d..619c7df0d27f 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1156,7 +1156,7 @@ 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
@@ -1171,7 +1171,8 @@ 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",