Re: [PATCH v3 3/4] memory: omap-gpmc: Use a compatible match table when checking for NAND controller

From: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
To: Roger Quadros <rogerq@kernel.org>, tony@atomide.com
Cc: robh@kernel.org, kishon@ti.com, nm@ti.com, vigneshr@ti.com,
	linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org
Subject: Re: [PATCH v3 3/4] memory: omap-gpmc: Use a compatible match table when checking for NAND controller
Date: Fri, 17 Dec 2021 16:21:57 +0100	[thread overview]
Message-ID: <88ff0e3e-6709-68fc-88cb-f915dfddbe86@canonical.com> (raw)
In-Reply-To: <20211217102945.17432-4-rogerq@kernel.org>

On 17/12/2021 11:29, Roger Quadros wrote:
> As more compatibles can be added to the GPMC NAND controller driver
> use a compatible match table.
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>
> ---
>  drivers/memory/omap-gpmc.c                   | 8 +++++++-
>  drivers/mtd/nand/raw/omap2.c                 | 2 +-
>  include/linux/platform_data/mtd-nand-omap2.h | 5 +++++
>  3 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
> index 624153048182..814ddb45c13d 100644
> --- a/drivers/memory/omap-gpmc.c
> +++ b/drivers/memory/omap-gpmc.c
> @@ -2091,6 +2091,7 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
>  	u32 val;
>  	struct gpio_desc *waitpin_desc = NULL;
>  	struct gpmc_device *gpmc = platform_get_drvdata(pdev);
> +	bool is_nand = false;
>  
>  	if (of_property_read_u32(child, "reg", &cs) < 0) {
>  		dev_err(&pdev->dev, "%pOF has no 'reg' property\n",
> @@ -2183,7 +2184,12 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
>  		}
>  	}
>  
> -	if (of_device_is_compatible(child, "ti,omap2-nand")) {
> +#if defined(CONFIG_MTD_NAND_OMAP2)

if (IS_ENABLED()) is preferred. If needed, you could make omap_nand_ids
symbol visible always (so without ifdef around it), because extern
structure should not have impact when not defined (if I recall
correctly...).

> +	if (of_match_node(omap_nand_ids, child))
> +		is_nand = true;
> +#endif
> +
> +	if (is_nand) {
>  		/* NAND specific setup */
>  		val = 8;
>  		of_property_read_u32(child, "nand-bus-width", &val);
> diff --git a/drivers/mtd/nand/raw/omap2.c b/drivers/mtd/nand/raw/omap2.c
> index b26d4947af02..fff834ee726f 100644
> --- a/drivers/mtd/nand/raw/omap2.c
> +++ b/drivers/mtd/nand/raw/omap2.c
> @@ -2352,7 +2352,7 @@ static int omap_nand_remove(struct platform_device *pdev)
>  	return ret;
>  }
>  
> -static const struct of_device_id omap_nand_ids[] = {
> +const struct of_device_id omap_nand_ids[] = {
>  	{ .compatible = "ti,omap2-nand", },
>  	{},
>  };

I think OMAP2 NAND driver can be a module, so this should have
EXPORT_SYMBOL.

> diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h
> index de6ada739121..e1bb90a8db03 100644
> --- a/include/linux/platform_data/mtd-nand-omap2.h
> +++ b/include/linux/platform_data/mtd-nand-omap2.h
> @@ -61,4 +61,9 @@ struct gpmc_nand_regs {
>  	void __iomem	*gpmc_bch_result5[GPMC_BCH_NUM_REMAINDER];
>  	void __iomem	*gpmc_bch_result6[GPMC_BCH_NUM_REMAINDER];
>  };
> +
> +#if defined(CONFIG_MTD_NAND_OMAP2)
> +extern const struct of_device_id omap_nand_ids[];
> +#endif
> +
>  #endif
> 

Best regards,
Krzysztof