spi: bitbang: Make setup_transfer() callback optional
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>
Signed-off-by: Mark Brown <broonie@kernel.org>
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 @@
{
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 @@
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 @@
/* 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;
}