mtd: st_spi_fsm: Update Macronix 'QE' configuration

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=cc6668637ebed620eaafc807802f3d85b193f534
Commit:     cc6668637ebed620eaafc807802f3d85b193f534
Parent:     009e7e61b1f15b16964f1b4b6bb1e30e6b03dc3b
Author:     Angus Clark <angus.clark at st.com>
AuthorDate: Wed Mar 26 16:39:17 2014 +0000
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Mon Apr 14 11:22:59 2014 -0700

    mtd: st_spi_fsm: Update Macronix 'QE' configuration
    
    Update the configuration of the Macronix 'QE' bit, such that
    we only set or clear the bit if required.
    
    Signed-off-by: Angus Clark <angus.clark at st.com>
    Signed-off-by: Lee Jones <lee.jones at linaro.org>
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
 drivers/mtd/devices/st_spi_fsm.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/devices/st_spi_fsm.c b/drivers/mtd/devices/st_spi_fsm.c
index 40eb830..f86d3e0 100644
--- a/drivers/mtd/devices/st_spi_fsm.c
+++ b/drivers/mtd/devices/st_spi_fsm.c
@@ -1164,12 +1164,27 @@ static int stfsm_mx25_config(struct stfsm *fsm)
 					      CFG_ERASESEC_TOGGLE_32BIT_ADDR);
 	}
 
-	/* For QUAD mode, set 'QE' STATUS bit */
+	/* Check status of 'QE' bit */
+	stfsm_read_status(fsm, FLASH_CMD_RDSR, &sta);
 	data_pads = ((fsm->stfsm_seq_read.seq_cfg >> 16) & 0x3) + 1;
 	if (data_pads == 4) {
-		stfsm_read_status(fsm, FLASH_CMD_RDSR, &sta);
-		sta |= MX25_STATUS_QE;
-		stfsm_write_status(fsm, sta, 1);
+		if (!(sta & MX25_STATUS_QE)) {
+			/* Set 'QE' */
+			sta |= MX25_STATUS_QE;
+
+			stfsm_write_status(fsm, sta, 1);
+
+			stfsm_wait_busy(fsm);
+		}
+	} else {
+		if (sta & MX25_STATUS_QE) {
+			/* Clear 'QE' */
+			sta &= ~MX25_STATUS_QE;
+
+			stfsm_write_status(fsm, sta, 1);
+
+			stfsm_wait_busy(fsm);
+		}
 	}
 
 	return 0;