From: "Nandan, Apurva" <a-nandan@ti.com>
To: Mark Brown <broonie@kernel.org>
Cc: <linux-spi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Pratyush Yadav <p.yadav@ti.com>,
Vignesh Raghavendra <vigneshr@ti.com>
Subject: Re: [EXTERNAL] Re: [PATCH 2/2] spi: cadence-quadspi: Fix check condition for DTR ops
Date: Wed, 14 Jul 2021 18:24:28 +0530 [thread overview]
Message-ID: <bea11e83-2c26-57b5-1a42-8ce852dc26ba@ti.com> (raw)
In-Reply-To: <20210713183903.GH4098@sirena.org.uk>
On 14-Jul-21 12:09 AM, Mark Brown wrote:
> On Tue, Jul 13, 2021 at 12:57:42PM +0000, Apurva Nandan wrote:
>
>> + f_pdata->dtr = op->cmd.dtr &&
>> + (op->addr.dtr || !op->addr.nbytes) &&
>> + (op->data.dtr || !op->data.nbytes);
>
> I'm not sure anyone reading this code is going to figure out what it's
> doing without thinking about it, the combination of writing the bytes
> check with a !, putting it after the check for .dtr and not having any
> comments is a bit obscure. Something like
>
> (op->addr.nbytes && op.addr.dtr)
>
> might be a bit clearer, or a comment explicitly spelling it out.
>
Okay, I will add a comment explaining it, as other logic (with &&) won't
deliver the behavior we expect.
The logic it implements is: for an op to be dtr, if any phase has
non-zero bytes, it must have dtr field set as true. So, it does p
implies q: p->q = (!p || q) i.e. if phase has non-zero bytes (p) then
check its dtr field (q). If all phases are empty, then follow what
op.cmd.dtr says.
Regards,
Apurva Nandan
next prev parent reply other threads:[~2021-07-14 12:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-13 12:57 [PATCH 0/2] spi: cadence-quadspi: Fix DTR op checks and timeout in SPI NAND write operations Apurva Nandan
2021-07-13 12:57 ` [PATCH 1/2] spi: cadence-quadspi: Disable Auto-HW polling Apurva Nandan
2021-07-13 18:25 ` Mark Brown
2021-07-14 13:22 ` Nandan, Apurva
2021-07-14 16:28 ` Mark Brown
2021-07-14 17:51 ` Apurva Nandan
2021-07-15 16:27 ` Apurva Nandan
2021-07-15 16:41 ` Mark Brown
2021-07-15 18:36 ` Pratyush Yadav
2021-07-16 18:04 ` Mark Brown
2021-07-13 12:57 ` [PATCH 2/2] spi: cadence-quadspi: Fix check condition for DTR ops Apurva Nandan
2021-07-13 18:39 ` Mark Brown
2021-07-14 12:54 ` Nandan, Apurva [this message]
2021-07-16 18:31 ` (subset) [PATCH 0/2] spi: cadence-quadspi: Fix DTR op checks and timeout in SPI NAND write operations Mark Brown
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