Re: [PATCH v4 1/3] gpio: mvebu: add pwm support for Armada 8K/7K - Russell King

From: Russell King - ARM Linux admin <linux@armlinux•org.uk>
To: Baruch Siach <baruch@tkos•co.il>
Cc: "Andrew Lunn" <andrew@lunn•ch>,
	"Sascha Hauer" <s.hauer@pengutronix•de>,
	"Thomas Petazzoni" <thomas.petazzoni@bootlin•com>,
	linux-pwm@vger•kernel.org,
	"Linus Walleij" <linus.walleij@linaro•org>,
	"Chris Packham" <chris.packham@alliedtelesis•co.nz>,
	"Rob Herring" <robh+dt@kernel•org>,
	"Bartosz Golaszewski" <bgolaszewski@baylibre•com>,
	devicetree@vger•kernel.org,
	"Thierry Reding" <thierry.reding@gmail•com>,
	linux-gpio@vger•kernel.org,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix•de>,
	"Ralph Sennhauser" <ralph.sennhauser@gmail•com>,
	"Lee Jones" <lee.jones@linaro•org>,
	"Gregory Clement" <gregory.clement@bootlin•com>,
	linux-arm-kernel@lists•infradead.org,
	"Sebastian Hesselbarth" <sebastian.hesselbarth@gmail•com>
Subject: Re: [PATCH v4 1/3] gpio: mvebu: add pwm support for Armada 8K/7K
Date: Mon, 4 Jan 2021 10:06:53 +0000	[thread overview]
Message-ID: <20210104100653.GB1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <61a022834dce86eefa3144e696078946f332bdfe.1607601615.git.baruch@tkos.co.il>

On Thu, Dec 10, 2020 at 02:15:58PM +0200, Baruch Siach wrote:
> @@ -781,51 +787,80 @@ static int mvebu_pwm_probe(struct platform_device *pdev,
>  	struct device *dev = &pdev->dev;
>  	struct mvebu_pwm *mvpwm;
>  	void __iomem *base;
> +	u32 offset;
>  	u32 set;
>  
> -	if (!of_device_is_compatible(mvchip->chip.of_node,
> -				     "marvell,armada-370-gpio"))
> -		return 0;
> -
> -	/*
> -	 * There are only two sets of PWM configuration registers for
> -	 * all the GPIO lines on those SoCs which this driver reserves
> -	 * for the first two GPIO chips. So if the resource is missing
> -	 * we can't treat it as an error.
> -	 */
> -	if (!platform_get_resource_byname(pdev, IORESOURCE_MEM, "pwm"))
> +	if (of_device_is_compatible(mvchip->chip.of_node,
> +				    "marvell,armada-370-gpio")) {
> +		/*
> +		 * There are only two sets of PWM configuration registers for
> +		 * all the GPIO lines on those SoCs which this driver reserves
> +		 * for the first two GPIO chips. So if the resource is missing
> +		 * we can't treat it as an error.
> +		 */
> +		if (!platform_get_resource_byname(pdev, IORESOURCE_MEM, "pwm"))
> +			return 0;
> +		offset = 0;
> +	} else if (mvchip->soc_variant == MVEBU_GPIO_SOC_VARIANT_A8K) {
> +		int ret = of_property_read_u32(dev->of_node,
> +					       "marvell,pwm-offset", &offset);
> +		if (ret < 0)
> +			return 0;

The reason my patches were rejected was because I was trying to keep
compatibility with the existing DTs w.r.t the clock - and Uwe didn't
like that.

I notice that you keep compatibility by detecting the presence or
absence of the marvell,pwm-offset property which achieves the same
goal.

Also, you are missing fixing a bug in the PWM register calculations
for get_state().

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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