Re: [PATCH v2 01/14] mtd: nand: pxa3xx: Introduce 'marvell,armada370-nand' compatible string

[Brian Norris <computersforpeace@gmail.com>]

On Wed, Aug 07, 2013 at 09:31:06AM -0300, Ezequiel Garcia wrote:
> This driver supports NFCv1 (as found in PXA SoC) and NFCv2 (as found in
> Armada 370/XP SoC). As both controller has a few differences, a way of
> distinguishing between the two is needed.
> 
> This commit introduces a new compatible string 'marvell,armada370-nand'
> and assigns a compatible data of type enum pxa3xx_nand_variant to allow
> such distinction.
> 
> Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
> ---
>  drivers/mtd/nand/pxa3xx_nand.c | 38 +++++++++++++++++++++++++++++++++++++-
>  1 file changed, 37 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
> index 501e380..2582e1f 100644
> --- a/drivers/mtd/nand/pxa3xx_nand.c
> +++ b/drivers/mtd/nand/pxa3xx_nand.c
> @@ -123,6 +123,11 @@ enum {
>  	STATE_READY,
>  };
>  
> +enum pxa3xx_nand_variant {
> +	PXA3XX_NAND_VARIANT_PXA,
> +	PXA3XX_NAND_VARIANT_ARMADA370,
> +};
> +
>  struct pxa3xx_nand_host {
>  	struct nand_chip	chip;
>  	struct pxa3xx_nand_cmdset *cmdset;
> @@ -171,6 +176,12 @@ struct pxa3xx_nand_info {
>  	struct pxa3xx_nand_host *host[NUM_CHIP_SELECT];
>  	unsigned int		state;
>  
> +	/*
> +	 * This driver supports NFCv1 (as found in PXA SoC)
> +	 * and NFCv2 (as found in Armada 370/XP SoC).
> +	 */
> +	enum pxa3xx_nand_variant variant;
> +
>  	int			cs;
>  	int			use_ecc;	/* use HW ECC ? */
>  	int			use_dma;	/* use DMA ? */
> @@ -1192,7 +1203,14 @@ static int pxa3xx_nand_remove(struct platform_device *pdev)
>  
>  #ifdef CONFIG_OF
>  static struct of_device_id pxa3xx_nand_dt_ids[] = {
> -	{ .compatible = "marvell,pxa3xx-nand" },
> +	{
> +		.compatible = "marvell,pxa3xx-nand",
> +		.data       = (void *) PXA3XX_NAND_VARIANT_PXA,

It's a little more common to avoid a space between the cast and the
rvalue. But that's a nitpick that can go either way (it's not in
CodingStyle, for one).

> +	},
> +	{
> +		.compatible = "marvell,armada370-nand",
> +		.data       = (void *) PXA3XX_NAND_VARIANT_ARMADA370,
> +	},
>  	{}
>  };
>  MODULE_DEVICE_TABLE(of, pxa3xx_nand_dt_ids);
> @@ -1221,11 +1239,28 @@ static int pxa3xx_nand_probe_dt(struct platform_device *pdev)
>  
>  	return 0;
>  }
> +
> +static enum pxa3xx_nand_variant
> +pxa3xx_nand_get_variant(struct platform_device *pdev)
> +{
> +	const struct of_device_id *of_id =
> +			of_match_device(pxa3xx_nand_dt_ids, &pdev->dev);
> +	if (!of_id)
> +		return PXA3XX_NAND_VARIANT_PXA;
> +	return (enum pxa3xx_nand_variant) of_id->data;
> +}
>  #else
>  static inline int pxa3xx_nand_probe_dt(struct platform_device *pdev)
>  {
>  	return 0;
>  }

It looks like before this patch, you don't actually need the whole
#ifdef/#else CONFIG_OF block. All the of_* helpers have default inline
implementations that allow things to compile even without CONFIG_OF. So
without CONFIG_OF, of_match_device() will just return NULL and the
compiler can easiliy figure out that pxa3xx_nand_probe_dt() always
should return 0.

IOW, you only need a single pxa3xx_nand_probe_dt() implementation.

And directly related to this patch: you don't need two
pxa3xx_nand_get_variant() implementations either. Again,
of_match_device() returns NULL in the !defined(CONFIG_OF) case.

> +
> +static enum pxa3xx_nand_variant
> +pxa3xx_nand_get_variant(struct platform_device *pdev)
> +{
> +	/* Default lefacy (non-DT) variant */

s/lefacy/legacy/

> +	return PXA3XX_NAND_VARIANT_PXA;
> +}

Given the above comments, you won't need this version of
pxa3xx_nand_get_variant().

>  #endif
>  
>  static int pxa3xx_nand_probe(struct platform_device *pdev)
> @@ -1252,6 +1287,7 @@ static int pxa3xx_nand_probe(struct platform_device *pdev)
>  	}
>  
>  	info = platform_get_drvdata(pdev);
> +	info->variant = pxa3xx_nand_get_variant(pdev);
>  	probe_success = 0;
>  	for (cs = 0; cs < pdata->num_cs; cs++) {
>  		info->cs = cs;

I would recommend rewriting this patch to remove the #ifdef CONFIG_OF.

Thanks,
Brian