linux-kernel - Re: [PATCH] pinctrl: at91: Enable slewrate by default on SAM9X60

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Message-ID: <20191029213757.GA8829@bogus>
Date:   Tue, 29 Oct 2019 16:37:57 -0500
From:   Rob Herring <robh@...nel.org>
To:     Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        ludovic.desroches@...rochip.com, linus.walleij@...aro.org,
        nicolas.ferre@...rochip.com, alexandre.belloni@...tlin.com,
        claudiu.beznea@...rochip.com
Subject: Re: [PATCH] pinctrl: at91: Enable slewrate by default on SAM9X60

On Thu, Oct 24, 2019 at 08:22:34PM +0300, Codrin Ciubotariu wrote:
> On SAM9X60, slewrate should be enabled on pins with a switching frequency
> below 50Mhz. Since most of our pins do not exceed this value, we enable
> slewrate by default. Pins with a switching value that exceeds 50Mhz will
> have to explicitly disable slewrate.
> 
> Suggested-by: Ludovic Desroches <ludovic.desroches@...rochip.com>
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
> ---
>  drivers/pinctrl/pinctrl-at91.c     | 4 ++--
>  include/dt-bindings/pinctrl/at91.h | 4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-at91.c b/drivers/pinctrl/pinctrl-at91.c
> index 117075b5798f..c135149e84e9 100644
> --- a/drivers/pinctrl/pinctrl-at91.c
> +++ b/drivers/pinctrl/pinctrl-at91.c
> @@ -85,8 +85,8 @@ enum drive_strength_bit {
>  					 DRIVE_STRENGTH_SHIFT)
>  
>  enum slewrate_bit {
> -	SLEWRATE_BIT_DIS,
>  	SLEWRATE_BIT_ENA,
> +	SLEWRATE_BIT_DIS,
>  };
>  
>  #define SLEWRATE_BIT_MSK(name)		(SLEWRATE_BIT_##name << SLEWRATE_SHIFT)
> @@ -669,7 +669,7 @@ static void at91_mux_sam9x60_set_slewrate(void __iomem *pio, unsigned pin,
>  {
>  	unsigned int tmp;
>  
> -	if (setting < SLEWRATE_BIT_DIS || setting > SLEWRATE_BIT_ENA)
> +	if (setting < SLEWRATE_BIT_ENA || setting > SLEWRATE_BIT_DIS)
>  		return;
>  
>  	tmp = readl_relaxed(pio + SAM9X60_PIO_SLEWR);
> diff --git a/include/dt-bindings/pinctrl/at91.h b/include/dt-bindings/pinctrl/at91.h
> index 3831f91fb3ba..e8e117306b1b 100644
> --- a/include/dt-bindings/pinctrl/at91.h
> +++ b/include/dt-bindings/pinctrl/at91.h
> @@ -27,8 +27,8 @@
>  #define AT91_PINCTRL_DRIVE_STRENGTH_MED			(0x2 << 5)
>  #define AT91_PINCTRL_DRIVE_STRENGTH_HI			(0x3 << 5)
>  
> -#define AT91_PINCTRL_SLEWRATE_DIS	(0x0 << 9)
> -#define AT91_PINCTRL_SLEWRATE_ENA	(0x1 << 9)
> +#define AT91_PINCTRL_SLEWRATE_ENA	(0x0 << 9)
> +#define AT91_PINCTRL_SLEWRATE_DIS	(0x1 << 9)

This is an ABI. You can't just change the definition.

Rob