[PATCH] mtd: nand: gpio: make nCE GPIO optional

[Marek Vasut]

On 02/10/2017 03:01 PM, Christophe Leroy wrote:
> On some hardware,

Can you be more specific or is that confidential ? Anyway, that's just
my curiosity, what hardware is done like that.

> the nCE signal is wired to the ChipSelect associated
> to bus address of the NAND, so it is automatically driven during the
> memory access and it is not managed by a GPIO.
> 
> Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>

Reviewed-by: Marek Vasut <marek.vasut at gmail.com>

but please wait for the NAND experts ...

> ---
>  drivers/mtd/nand/gpio.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mtd/nand/gpio.c b/drivers/mtd/nand/gpio.c
> index 0d24857..85294f1 100644
> --- a/drivers/mtd/nand/gpio.c
> +++ b/drivers/mtd/nand/gpio.c
> @@ -78,7 +78,9 @@ static void gpio_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
>  	gpio_nand_dosync(gpiomtd);
>  
>  	if (ctrl & NAND_CTRL_CHANGE) {
> -		gpio_set_value(gpiomtd->plat.gpio_nce, !(ctrl & NAND_NCE));
> +		if (gpio_is_valid(gpiomtd->plat.gpio_nce))
> +			gpio_set_value(gpiomtd->plat.gpio_nce,
> +				       !(ctrl & NAND_NCE));
>  		gpio_set_value(gpiomtd->plat.gpio_cle, !!(ctrl & NAND_CLE));
>  		gpio_set_value(gpiomtd->plat.gpio_ale, !!(ctrl & NAND_ALE));
>  		gpio_nand_dosync(gpiomtd);
> @@ -201,7 +203,8 @@ static int gpio_nand_remove(struct platform_device *pdev)
>  
>  	if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
>  		gpio_set_value(gpiomtd->plat.gpio_nwp, 0);
> -	gpio_set_value(gpiomtd->plat.gpio_nce, 1);
> +	if (gpio_is_valid(gpiomtd->plat.gpio_nce))
> +		gpio_set_value(gpiomtd->plat.gpio_nce, 1);
>  
>  	return 0;
>  }
> @@ -239,10 +242,13 @@ static int gpio_nand_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> -	ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nce, "NAND NCE");
> -	if (ret)
> -		return ret;
> -	gpio_direction_output(gpiomtd->plat.gpio_nce, 1);
> +	if (gpio_is_valid(gpiomtd->plat.gpio_nce)) {
> +		ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nce,
> +					"NAND NCE");
> +		if (ret)
> +			return ret;
> +		gpio_direction_output(gpiomtd->plat.gpio_nce, 1);
> +	}
>  
>  	if (gpio_is_valid(gpiomtd->plat.gpio_nwp)) {
>  		ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nwp,
> 


-- 
Best regards,
Marek Vasut