mtd: spi-nor: core: disable Octal DTR mode on suspend.

On resume, the init procedure will be run that will re-enable it.
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20201005153138.6437-14-p.yadav@ti.com

drivers/mtd/spi-nor/core.c

@@ -3216,6 +3216,20 @@ static void spi_nor_soft_reset(struct spi_nor *nor)
 	usleep_range(SPI_NOR_SRST_SLEEP_MIN, SPI_NOR_SRST_SLEEP_MAX);
 }
 
+/* mtd suspend handler */
+static int spi_nor_suspend(struct mtd_info *mtd)
+{
+	struct spi_nor *nor = mtd_to_spi_nor(mtd);
+	int ret;
+
+	/* Disable octal DTR mode if we enabled it. */
+	ret = spi_nor_octal_dtr_enable(nor, false);
+	if (ret)
+		dev_err(nor->dev, "suspend() failed\n");
+
+	return ret;
+}
+
 /* mtd resume handler */
 static void spi_nor_resume(struct mtd_info *mtd)
 {
@@ -3421,6 +3435,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
 	mtd->size = nor->params->size;
 	mtd->_erase = spi_nor_erase;
 	mtd->_read = spi_nor_read;
+	mtd->_suspend = spi_nor_suspend;
 	mtd->_resume = spi_nor_resume;
 
 	if (nor->params->locking_ops) {