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From: Andy Shevchenko <andy@kernel.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Linus Walleij <linusw@kernel.org>, Imre Kaloz <kaloz@openwrt.org>,
	Krzysztof Halasa <khalasa@piap.pl>,
	Bartosz Golaszewski <brgl@bgdev.pl>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org,
	devicetree@vger.kernel.org
Subject: Re: [PATCH 2/2] gpio: ixp4xx: Handle clock output on pin 14 and 15
Date: Thu, 21 Sep 2023 14:22:42 +0300	[thread overview]
Message-ID: <ZQwngrU9fxdSGSKs@smile.fi.intel.com> (raw)
In-Reply-To: <20230921-ixp4xx-gpio-clocks-v1-2-574942bf944a@linaro.org>

On Thu, Sep 21, 2023 at 12:23:46AM +0200, Linus Walleij wrote:
> This makes it possible to provide basic clock output on pins
> 14 and 15. The clocks are typically used by random electronics,
> not modeled in the device tree, so they just need to be provided
> on request.

...

> +	val = __raw_readl(g->base + IXP4XX_REG_GPCLK);

Do we need to read this...

>  	/*
>  	 * Make sure GPIO 14 and 15 are NOT used as clocks but GPIO on
>  	 * specific machines.
>  	 */
>  	if (of_machine_is_compatible("dlink,dsm-g600-a") ||
>  	    of_machine_is_compatible("iom,nas-100d"))
> -		__raw_writel(0x0, g->base + IXP4XX_REG_GPCLK);
> +		val = 0;

...if we are going to discard it anyway here?

Maybe

	if (...)
		val = 0;
	else
		val = readl();

?

...

> +	/*
> +	 * Enable clock outputs with default timings of requested clock.
> +	 * If you need control over TC and DC, add these to the device
> +	 * tree bindings and use them here.
> +	 */

Shouldn't this be integrated into PPS subsystem?

-- 
With Best Regards,
Andy Shevchenko



WARNING: multiple messages have this Message-ID (diff)
From: Andy Shevchenko <andy@kernel.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Linus Walleij <linusw@kernel.org>, Imre Kaloz <kaloz@openwrt.org>,
	Krzysztof Halasa <khalasa@piap.pl>,
	Bartosz Golaszewski <brgl@bgdev.pl>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org,
	devicetree@vger.kernel.org
Subject: Re: [PATCH 2/2] gpio: ixp4xx: Handle clock output on pin 14 and 15
Date: Thu, 21 Sep 2023 14:22:42 +0300	[thread overview]
Message-ID: <ZQwngrU9fxdSGSKs@smile.fi.intel.com> (raw)
In-Reply-To: <20230921-ixp4xx-gpio-clocks-v1-2-574942bf944a@linaro.org>

On Thu, Sep 21, 2023 at 12:23:46AM +0200, Linus Walleij wrote:
> This makes it possible to provide basic clock output on pins
> 14 and 15. The clocks are typically used by random electronics,
> not modeled in the device tree, so they just need to be provided
> on request.

...

> +	val = __raw_readl(g->base + IXP4XX_REG_GPCLK);

Do we need to read this...

>  	/*
>  	 * Make sure GPIO 14 and 15 are NOT used as clocks but GPIO on
>  	 * specific machines.
>  	 */
>  	if (of_machine_is_compatible("dlink,dsm-g600-a") ||
>  	    of_machine_is_compatible("iom,nas-100d"))
> -		__raw_writel(0x0, g->base + IXP4XX_REG_GPCLK);
> +		val = 0;

...if we are going to discard it anyway here?

Maybe

	if (...)
		val = 0;
	else
		val = readl();

?

...

> +	/*
> +	 * Enable clock outputs with default timings of requested clock.
> +	 * If you need control over TC and DC, add these to the device
> +	 * tree bindings and use them here.
> +	 */

Shouldn't this be integrated into PPS subsystem?

-- 
With Best Regards,
Andy Shevchenko



_______________________________________________
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linux-arm-kernel@lists.infradead.org
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  reply	other threads:[~2023-09-21 17:07 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-20 22:23 [PATCH 0/2] gpio: ixp4xx: Handle external clock output Linus Walleij
2023-09-20 22:23 ` Linus Walleij
2023-09-20 22:23 ` [PATCH 1/2] gpio: Rewrite IXP4xx GPIO bindings in schema Linus Walleij
2023-09-20 22:23   ` Linus Walleij
2023-09-21 18:44   ` Rob Herring
2023-09-21 18:44     ` Rob Herring
2023-09-20 22:23 ` [PATCH 2/2] gpio: ixp4xx: Handle clock output on pin 14 and 15 Linus Walleij
2023-09-20 22:23   ` Linus Walleij
2023-09-21 11:22   ` Andy Shevchenko [this message]
2023-09-21 11:22     ` Andy Shevchenko
2023-09-21 12:34     ` Linus Walleij
2023-09-21 12:34       ` Linus Walleij

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