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From: Yicong Yang <yangyicong@hisilicon.com>
To: <tudor.ambarus@microchip.com>, <linux-mtd@lists.infradead.org>
Cc: vigneshr@ti.com, sergei.shtylyov@cogentembedded.com,
	richard@nod.at, me@yadavpratyush.com, john.garry@huawei.com,
	linuxarm@huawei.com, yangyicong@hisilicon.com,
	alexander.sverdlin@nokia.com, miquel.raynal@bootlin.com
Subject: [RFC PATCH v2 0/2] Add support to Disable the flash quad mode
Date: Tue, 12 May 2020 19:26:57 +0800	[thread overview]
Message-ID: <1589282819-42358-1-git-send-email-yangyicong@hisilicon.com> (raw)

Previously we didn't disable the flash's quad mode when it's removed
Then comes the problem that if we next time load the flash
in SPI/Dual mode, it will not be correctly enabled as the quad enable
bits has not been cleared. I validated the condition on Cypress s25fs128s1.

This series adds the capability to disable the flash's quad mode. And
restore the flash when it's removed in spi_nor_restore().

RFC:
- I cleared quad mode bit in spi_nor_restore() when flash removed or
shutdown, follow what reset 4byte address does. But I don't know if
there is a situation that the flash is in quad mode by default. If so,
we should disable it in probe stage.
- The issue occurs when the user switch the spi mode of the flash.
Not sure whether a situation exists.

Changes since v1:
- modify the comments and fix the condition suggested by Pratyush's.
Link: https://lore.kernel.org/linux-mtd/1587720044-49172-1-git-send-email-yangyicong@hisilicon.com/

Yicong Yang (2):
  mtd: spi-nor: Add capability to disable flash quad mode
  mtd: spi-nor: Disable the flash quad mode in spi_nor_restore()

 drivers/mtd/spi-nor/core.c | 56 +++++++++++++++++++++++++++++++++-------------
 drivers/mtd/spi-nor/core.h |  8 +++----
 2 files changed, 44 insertions(+), 20 deletions(-)

-- 
2.8.1


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             reply	other threads:[~2020-05-12 11:27 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-12 11:26 Yicong Yang [this message]
2020-05-12 11:26 ` [RFC PATCH v2 1/2] mtd: spi-nor: Add capability to disable flash quad mode Yicong Yang
2020-06-15 10:53   ` Pratyush Yadav
2020-06-16  7:10     ` Yicong Yang
2020-05-12 11:26 ` [RFC PATCH v2 2/2] mtd: spi-nor: Disable the flash quad mode in spi_nor_restore() Yicong Yang
2020-06-15 10:56   ` Pratyush Yadav
2020-06-15  9:19 ` [RFC PATCH v2 0/2] Add support to Disable the flash quad mode Yicong Yang

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