[PATCH] cmd: Ensure sf operates on spi flash

[Sean Anderson <seanga2@gmail.com>]

Currently, the sf command will probe anything attached to an spi bus, regardless
of whether it is UCLASS_SPI_FLASH. This came up when testing the mmc_spi driver,
which is accessed via spi but is UCLASS_MMC. If the uclass is not what sf
expects, then the "flash" variable will not actually have type spi_nor. This
patch adds a check so we don't clobber any data if the user requests us to probe
a device which is not an spi flash.

Signed-off-by Sean Anderson <seanga2@gmail.com>
---
 cmd/sf.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/cmd/sf.c b/cmd/sf.c
index e993b3e5ad..21a410c40f 100644
--- a/cmd/sf.c
+++ b/cmd/sf.c
@@ -132,6 +132,10 @@ static int do_spi_flash_probe(int argc, char * const argv[])
 		printf("Failed to initialize SPI flash at %u:%u (error %d)\n",
 		       bus, cs, ret);
 		return 1;
+	} else if (new->driver->id != UCLASS_SPI_FLASH) {
+		printf("SPI device is not SPI flash: uclass is %d, expected %d\n",
+		       new->driver->id, UCLASS_SPU_FLASH);
+		return 1;
 	}
 
 	flash = dev_get_uclass_priv(new);
-- 
2.25.0