Re: [PATCH v6 05/17] spi: spi-mem: add execute_tuning callback and spi_mem_execute_tuning()

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Santhosh Kumar K <s-k6@ti.com>
Cc: <broonie@kernel.org>,  <robh@kernel.org>,  <krzk+dt@kernel.org>,
	<conor+dt@kernel.org>,  <richard@nod.at>,  <vigneshr@ti.com>,
	<pratyush@kernel.org>,  <mwalle@kernel.org>,
	<takahiro.kuwano@infineon.com>,  <linux-spi@vger.kernel.org>,
	<devicetree@vger.kernel.org>,  <linux-kernel@vger.kernel.org>,
	<linux-mtd@lists.infradead.org>,  <praneeth@ti.com>,
	 <u-kumar1@ti.com>, <a-dutta@ti.com>
Subject: Re: [PATCH v6 05/17] spi: spi-mem: add execute_tuning callback and spi_mem_execute_tuning()
Date: Wed, 29 Jul 2026 10:37:31 +0200	[thread overview]
Message-ID: <87qzkmmbsk.fsf@bootlin.com> (raw)
In-Reply-To: <20260723110219.3180747-6-s-k6@ti.com> (Santhosh Kumar K.'s message of "Thu, 23 Jul 2026 16:32:07 +0530")

Hello Santhosh,

On 23/07/2026 at 16:32:07 +0530, Santhosh Kumar K <s-k6@ti.com> wrote:

> Add an execute_tuning callback to struct spi_controller_mem_ops. The
> callback receives a mandatory read op template and an optional write op
> template. On success the controller sets op->max_freq in each provided
> template to the validated clock rate.
>
> Add the corresponding spi_mem_execute_tuning() wrapper that checks for
> callback availability and returns -EOPNOTSUPP when the controller has
> not implemented it, allowing callers to handle controllers that do not
> support tuning gracefully.
>
> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> Signed-off-by: Santhosh Kumar K <s-k6@ti.com>

Sashiko found two issues which I think are easy yet worth fixing:

- [High] spi_mem_execute_tuning() directly invokes the controller callback without acquiring the SPI bus locks or ensuring the controller is powered on.
- [High] spi_mem_execute_tuning() does not check if the SPI device is using a GPIO chip select before invoking the hardware tuning callback.

Can you please have a look?

Thanks,
Miquèl