[PATCH AUTOSEL for 4.14 069/135] mtd: spi-nor: stm32-quadspi: Fix uninitialized error return code

[alexander . levin]

From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>

[ Upstream commit 05521bd3d117704a1458eb4d0c3ae821858658f2 ]

With gcc 4.1.2:

    drivers/mtd/spi-nor/stm32-quadspi.c: In function âstm32_qspi_tx_pollâ:
    drivers/mtd/spi-nor/stm32-quadspi.c:230: warning: âretâ may be used uninitialized in this function

Indeed, if stm32_qspi_cmd.len is zero, ret will be uninitialized.
This length is passed from outside the driver using the
spi_nor.{read,write}{,_reg}() callbacks.

Several functions in drivers/mtd/spi-nor/spi-nor.c (e.g. write_enable(),
write_disable(), and erase_chip()) call spi_nor.write_reg() with a zero
length.

Fix this by returning an explicit zero on success.

Fixes: 0d43d7ab277a048c ("mtd: spi-nor: add driver for STM32 quad spi flash controller")
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Acked-by: Ludovic Barre <ludovic.barre@xxxxxx>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
 drivers/mtd/spi-nor/stm32-quadspi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c b/drivers/mtd/spi-nor/stm32-quadspi.c
index 86c0931543c5..ad6a3e1844cb 100644
--- a/drivers/mtd/spi-nor/stm32-quadspi.c
+++ b/drivers/mtd/spi-nor/stm32-quadspi.c
@@ -240,12 +240,12 @@ static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
 						 STM32_QSPI_FIFO_TIMEOUT_US);
 		if (ret) {
 			dev_err(qspi->dev, "fifo timeout (stat:%#x)\n", sr);
-			break;
+			return ret;
 		}
 		tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
 	}
 
-	return ret;
+	return 0;
 }
 
 static int stm32_qspi_tx_mm(struct stm32_qspi *qspi,
-- 
2.11.0