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Subject: Re: [PATCH 1/3] spi: spi-mem: add automatic poll status functions
To:     Mark Brown <broonie@kernel.org>
CC:     Pratyush Yadav <p.yadav@ti.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
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        Alexandre Torgue <alexandre.torgue@foss.st.com>,
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        <linux-kernel@vger.kernel.org>, <christophe.kerello@foss.st.com>
References: <20210426143934.25275-1-patrice.chotard@foss.st.com>
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 <20210426162610.erpt5ubeddx7paeq@ti.com>
 <20210426165118.GH4590@sirena.org.uk>
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 <20210430155623.GD5981@sirena.org.uk>
From:   Patrice CHOTARD <patrice.chotard@foss.st.com>
Message-ID: <f472d75d-7549-191b-1b42-4e3921280c49@foss.st.com>
Date:   Wed, 5 May 2021 09:21:15 +0200
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Hi Mark

On 4/30/21 5:56 PM, Mark Brown wrote:
> On Fri, Apr 30, 2021 at 04:22:34PM +0200, Patrice CHOTARD wrote:
>> On 4/26/21 6:51 PM, Mark Brown wrote:
>>> On Mon, Apr 26, 2021 at 09:56:12PM +0530, Pratyush Yadav wrote:
> 
>>> Is it possible there's some situation where you're waiting for some bits
>>> to clear as well?
> 
>> Yes, we are waiting STATUS_BUSY bit to be cleared, see patch 2 which is making 
>> usage of this API.
> 
> Then the inverse question applies - is there no circumstance where we
> might be waiting for a bit to be set?
> 
>>> We already have the core handling other timeouts.  We don't pass around
>>> completions but rather have an API function that the driver has to call
>>> when the operation completes, a similar pattern might work here.  Part
> 
>> So, if i correctly understood, you make allusion to what is already done
>> in SPI core framework with spi_finalize_current_transfer() right ?
> 
> Yes, and _current_message().
> 
>>> of the thing with those APIs which I'm missing here is that this will
>>> just return -EOPNOTSUPP if the driver can't do the delay in hardware, I
>>> think it would be cleaner if this API were similar and the core dealt
>>> with doing the delay/poll on the CPU.  That way the users don't need to
>>> repeat the handling for the offload/non-offload cases.
> 
>> Sorry, i didn't catch what you mean here. In PATCH 2, that's the case,
>> if spi_mem_poll_status() is not supported, the core is dealing with 
>> the delay/poll on the CPU in spinand_wait().
> 
> That's in the NAND core, not in spi-mem.  Any other users of spi-mem
> will also need to open code stuff.
> 

Ok, got it, i will transfer what is done in spi_nand_wait() into spi_mem_poll_status() 
in order to get the full feature in spi-mem which will profit to all spi-mem users as requested.

Thanks
Patrice