linux-kernel - Re: [PATCH 2/3] mtd: spi-nor: support vcc-supply regulator

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Message-ID: <20240920090959.67y7h57yirtahfuh@pengutronix.de>
Date: Fri, 20 Sep 2024 11:09:59 +0200
From: Marco Felsch <m.felsch@...gutronix.de>
To: "Peng Fan (OSS)" <peng.fan@....nxp.com>
Cc: Tudor Ambarus <tudor.ambarus@...aro.org>,
	Pratyush Yadav <pratyush@...nel.org>,
	Michael Walle <mwalle@...nel.org>,
	Miquel Raynal <miquel.raynal@...tlin.com>,
	Richard Weinberger <richard@....at>,
	Vignesh Raghavendra <vigneshr@...com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>, devicetree@...r.kernel.org,
	Peng Fan <peng.fan@....com>, imx@...ts.linux.dev,
	linux-kernel@...r.kernel.org, linux-mtd@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 2/3] mtd: spi-nor: support vcc-supply regulator

On 24-09-20, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@....com>
> 
> spi nor flash needs power supply to work properly. The power supply
> maybe software controllable per board design. So add the support
> for an optional vcc-supply regulator.
> 
> Signed-off-by: Peng Fan <peng.fan@....com>
> ---
>  drivers/mtd/spi-nor/core.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index 9d6e85bf227b..0449afe6bb20 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -17,6 +17,7 @@
>  #include <linux/mtd/spi-nor.h>
>  #include <linux/mutex.h>
>  #include <linux/of_platform.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/sched/task_stack.h>
>  #include <linux/sizes.h>
>  #include <linux/slab.h>
> @@ -3462,6 +3463,10 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>  	if (!nor->bouncebuf)
>  		return -ENOMEM;
>  
> +	ret = devm_regulator_get_enable_optional(dev, "vcc");
> +	if (ret)

This returns -ENODEV if no regulator was specified. In general all
SPI-NOR devices need a VCC supply, so don't use the regulator optional
API here, please check the regulator API doc.

In contrast to that the dt-bindings should have the vcc-supply as
optional to not cause a regression for exisiting systems.

Regards,
  Marco

> +		return ret;
> +
>  	ret = spi_nor_hw_reset(nor);
>  	if (ret)
>  		return ret;
> 
> -- 
> 2.37.1
> 
> 
>