openwrtv3/target/linux/generic/backport-4.9/062-v4.11-0002-mtd-spi-nor-improve-macronix_quad_enable.patch

From 1e99d0d51ec97bf48edd277658004ce030543d98 Mon Sep 17 00:00:00 2001
From: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Date: Tue, 6 Dec 2016 17:01:41 +0100
Subject: [PATCH] mtd: spi-nor: improve macronix_quad_enable()

The patch checks whether the Quad Enable bit is already set in the Status
Register. If so, the function exits immediately with a successful return
code.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
Acked-by: Marek Vasut <marek.vasut@gmail.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1311,6 +1311,9 @@ static int macronix_quad_enable(struct s
 	val = read_sr(nor);
 	if (val < 0)
 		return val;
+	if (val & SR_QUAD_EN_MX)
+		return 0;
+
 	write_enable(nor);
 
 	write_sr(nor, val | SR_QUAD_EN_MX);