[PATCH 2/2] mtd: spi-nor: Disable the flash quad mode in spi_nor_restore()

[Matthias Weißer]

Am Di., 16. Juni 2020 um 15:03 Uhr schrieb Yicong Yang
<yangyicong at hisilicon.com>:
> If the flash's quad mode is enabled, it'll remain in the quad mode when
> it's removed. If we drive the flash next time in SPI/Dual mode, then
> problem occurs as the flash's quad enable bit is not cleared.

On flash devices with a non-volatile quad enable bit (we use S25FL512S)
this will wear out the quad enable bit as on every boot the bit is
set and reset on shutdown. Or do I miss something here?

> Disable the quad mode in spi_nor_restore(), the flash will leave
> quad mode when remove. This will make sure the flash always enter the
> correct mode when loaded.

We have a system which relies on an enabled quad mode on boot
(bootloader uses quad mode without enabling it) so using this patch
will prevent our device from booting.

Regards,
Matthias