linux-kernel - Re: [RFC PATCH] mtd: rawnand: ams-delta: use ->exec

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Date:   Wed, 03 Oct 2018 15:55:25 +0200
From:   Janusz Krzysztofik <jmkrzyszt@...il.com>
To:     Boris Brezillon <boris.brezillon@...tlin.com>
Cc:     Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Janusz Krzysztofik <jmkrzyszt@...il.com>
Subject: Re: [RFC PATCH] mtd: rawnand: ams-delta: use ->exec_op()

On Wednesday, October 3, 2018 2:30:54 PM CEST Boris Brezillon wrote:
> Hi Janusz,
> 
> On Wed,  3 Oct 2018 14:00:28 +0200
> Janusz Krzysztofik <jmkrzyszt@...il.com> wrote:
> 
> > Replace legacy callbacks with ->select_chip() and ->exec_op().
> 
> Thanks for working on that, that's really appreciated.
> 
> > 
> > Implementation of NAND_OP_WAITRDY_INSTR has been based on legacy
> > nand_wait_ready(),
> 
> I don't remember what the ams-delta ->dev_ready()/->waitfunc() hooks
> are doing, but is shouldn't be too hard to replace them by an
> ams_delta_wait_ready() func.

Default nand_wait() is used as ->waitfunc(), and ->dev_ready() returns R/B 
GPIO pin status.

> > otherwise that function would probabaly have to be
> 
> 				^ probably

Do you think other drivers which now provide ->dev_ready() won't require 
reimplementation of nand_wait_ready()?

> > reimplemented inside the driver.  Hence, legacy callback ->dev_ready()
> > is still used.
> > 
> > Use of IO_ADDR_R and IO_ADDR_W legacy structure members will be dropped
> > later, as soon as the driver is converted to use GPIO API for data I/O.
> 
> In the meantime, can you move the iomem pointer to the ams_delta
> private struct so that this driver no longer uses the ->IO_ADDR_R/W
> fields?

OK

> > 
> > Suggested-by: Boris Brezillon <boris.brezillon@...tlin.com>
> > Signed-off-by: Janusz Krzysztofik <jmkrzyszt@...il.com>
> > ---
> > Hi,
> > 
> > I've not tested the change on hardware yet as I'm not sure if:
> > - handling of NCE limited to that inside ->select_chip() is
> >   sufficient,
> 
> I think it is.
> 
> > - releasing ALE / CLE immediately after ams_delta_write_buf() is
> >   correct.
> 
> Well, you should probably consider waiting for instr->ctx.delay_ns
> nanoseconds after each instruction, but, if it was working before the
> conversion to ->exec_op(), it should work just fine now.

OK, I'll give it a try.

Thanks,
Janusz