linux-kernel - Re: [PATCH] pinctrl: renesas: rza1: Check pin state before configuring

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Message-ID: <aICI6M61N9_PH35L@ninjato>
Date: Wed, 23 Jul 2025 09:02:00 +0200
From: Wolfram Sang <wsa+renesas@...g-engineering.com>
To: Magnus Damm <damm@...nsource.se>
Cc: linux-renesas-soc@...r.kernel.org, geert+renesas@...der.be,
	linux-gpio@...r.kernel.org, linus.walleij@...aro.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] pinctrl: renesas: rza1: Check pin state before
 configuring

Hi Magnus,

On Sat, Jul 12, 2025 at 05:25:38PM +0200, Magnus Damm wrote:
> From: Magnus Damm <damm@...nsource.se>
> 
> Add code to the RZ/A1 pinctrl driver to check the state of the pin before
> writing any registers. As it is without this patch, resetting the pin state
> for every pin regardless of preious state might negatively be affecting
> certain shared pins like for instance address and data bus pins.
> 
> Signed-off-by: Magnus Damm <damm@...nsource.se>
> ---
> 
>   This makes the following patch work with Linux:
>   [PATCH] Update r7s72100 Genmai DTS to include NOR Flash pinctrl

True that.

Tested-by: Wolfram Sang <wsa+renesas@...g-engineering.com>

I can't say if it is feasible to have this code in the driver. I leave
this for Geert or the RZ team. But I can say it works with the above DTS
patch.

> +static int rza1_pin_mux_needs_update(struct rza1_pinctrl *rza1_pctl,
> +				     struct rza1_mux_conf *mux_conf)

Minor: I'd make this a bool, though...

> +	if (!!(mux_flags & MUX_FLAGS_BIDIR) !=
> +	  !!rza1_get_bit(port, RZA1_PBDC_REG, pin))
> +		return 1;

... and treturn true / false.

Happy hacking,

   Wolfram


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