[EXT] Re: [PATCH] mtd: spi-nor: Add prep/unprep for spi_nor_resume

Han Xu han.xu at nxp.com
Thu Jun 6 15:33:29 PDT 2019

> -----Original Message-----
> From: Tudor.Ambarus at microchip.com <Tudor.Ambarus at microchip.com>
> Sent: Thursday, June 6, 2019 12:46 AM
> To: Han Xu <han.xu at nxp.com>; cyrille.pitchen at wedev4u.fr;
> marek.vasut at gmail.com
> Cc: boris.brezillon at free-electrons.com; f.fainelli at gmail.com;
> kdasu.kdev at gmail.com; richard at nod.at; linux-kernel at vger.kernel.org;
> linux-mtd at lists.infradead.org; dl-linux-imx <linux-imx at nxp.com>;
> computersforpeace at gmail.com
> Subject: [EXT] Re: [PATCH] mtd: spi-nor: Add prep/unprep for
> spi_nor_resume
> Caution: EXT Email
> Hi, Han,
> On 04/25/2019 12:08 AM, Han Xu wrote:
> > External E-Mail
> >
> >
> > In the new implemented spi_nor_resume function, the spi_nor_init()
> > should be braced by prep/unprep functions._
> >
> Would you please explain why this is needed? Have you tried a
> suspend/resume cycle while a write was in progress and it failed?

Same as all other functions that hooked up with mtd ops, such as
_read/_write/_lock/_unlock, the _resume function also need to call the
lower level controller's prep/unprep functions to properly handle runtime
pm and mutex.

I didn't try suspend/resume during writing, but found accessing registers
without enabling clock when system resumed.

> Thanks,
> ta

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