spi-bcm2835: Disable forced software CS

commit 04313c2a5fe850e7cf3ba246dad6a9b7448c626b from
https://github.com/raspberrypi/linux.git

Select software CS in bcm2708_common.dtsi, and disable the automatic
conversion in the driver to allow hardware CS to be re-enabled with an
overlay.

See: raspberrypi/linux#1547

Signed-off-by: Phil Elwell <[email protected]>
Signed-off-by: Xulin Sun <[email protected]>

Author: Phil Elwell

drivers/spi/spi-bcm2835.c

@@ -705,6 +705,7 @@ static int bcm2835_spi_setup(struct spi_device *spi)
 		return -EINVAL;
 	}
 
+#if 0
 	/* now translate native cs to GPIO */
 	/* first look for chip select pins in the devices pin groups */
 	for (pingroup_index = 0;
@@ -754,6 +755,7 @@ static int bcm2835_spi_setup(struct spi_device *spi)
 			spi->chip_select, spi->cs_gpio, err);
 		return err;
 	}
+#endif
 
 	return 0;
 }