Re: [PATCH V3 07/11] mfd: bcm2835-pm: Add support for BCM2711

[Lee Jones <lee.jones@linaro.org>]

On Tue, 07 Jun 2022, Stefan Wahren wrote:

> In BCM2711 the new RPiVid ASB took over V3D. The old ASB is still present
> with the ISP and H264 bits, and V3D is in the same place in the new ASB
> as the old one.
> 
> As per the devicetree bindings, BCM2711 will provide both the old and
> new ASB resources, so get both of them and pass them into
> 'bcm2835-power,' which will take care of selecting which one to use
> accordingly.
> 
> Since the RPiVid ASB's resources were being provided prior to formalizing
> the bindings[1], also support the old DT files that didn't use
> 'reg-names.'
> 
> Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
> Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
> 
> [1] See: 7dbe8c62ceeb ("ARM: dts: Add minimal Raspberry Pi 4 support")
> ---
>  drivers/mfd/bcm2835-pm.c       | 21 +++++++++++++++++++++
>  include/linux/mfd/bcm2835-pm.h |  1 +
>  2 files changed, 22 insertions(+)
> 
> diff --git a/drivers/mfd/bcm2835-pm.c b/drivers/mfd/bcm2835-pm.c
> index ff0dae5a026d..4a2be669674a 100644
> --- a/drivers/mfd/bcm2835-pm.c
> +++ b/drivers/mfd/bcm2835-pm.c
> @@ -28,6 +28,8 @@ static const struct mfd_cell bcm2835_power_devs[] = {
>  static int bcm2835_pm_get_pdata(struct platform_device *pdev,
>  				struct bcm2835_pm *pm)
>  {
> +	bool is_bcm2711 = of_device_is_compatible(pm->dev->of_node, "brcm,bcm2711-pm");
> +

Since this is only used once, probably better to call
of_device_is_compatible() in-place.

>  	/* If no 'reg-names' property is found we can assume we're using old
>  	 * firmware.
>  	 */
> @@ -39,6 +41,7 @@ static int bcm2835_pm_get_pdata(struct platform_device *pdev,
>  			return PTR_ERR(pm->base);
>  
>  		pm->asb = devm_platform_ioremap_resource(pdev, 1);
> +		pm->rpivid_asb = devm_platform_ioremap_resource(pdev, 2);
>  	} else {
>  		struct resource *res;
>  
> @@ -50,11 +53,28 @@ static int bcm2835_pm_get_pdata(struct platform_device *pdev,
>  						    "asb");
>  		if (res)
>  			pm->asb = devm_ioremap_resource(&pdev->dev, res);
> +
> +		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> +						    "rpivid_asb");
> +		if (res)
> +			pm->rpivid_asb = devm_ioremap_resource(&pdev->dev,
> +								res);
>  	}
>  
>  	if (IS_ERR(pm->asb))
>  		pm->asb = NULL;
>  
> +	if (IS_ERR(pm->rpivid_asb))
> +		pm->rpivid_asb = NULL;
> +
> +	/* Ensure that rpivid_asb is set only for BCM2711, so subsequent
> +	 * driver can rely on this and don't get confused by broken DTB.
> +	 */

Please use proper formatting.

> +	if (pm->rpivid_asb && !is_bcm2711) {
> +		dev_err(pm->dev, "Unexpected rpivid_asb register, please fix your DTB.\n");

Not sure we should be validating values from DT like this.

If incorrect hardware information is placed into DT, unexpected
behaviour will occur.  This is known.  Perhaps a mention of this
should be placed into the DT binding documentation, but checking for
it here seems odd.

Same goes for the previous patch come to think of it.  Please remove
the "update your DTB" warning from there too.

> +		return -EINVAL;
> +	}
> +
>  	return 0;
>  }
>  
> @@ -95,6 +115,7 @@ static int bcm2835_pm_probe(struct platform_device *pdev)
>  static const struct of_device_id bcm2835_pm_of_match[] = {
>  	{ .compatible = "brcm,bcm2835-pm-wdt", },
>  	{ .compatible = "brcm,bcm2835-pm", },
> +	{ .compatible = "brcm,bcm2711-pm", },
>  	{},
>  };
>  MODULE_DEVICE_TABLE(of, bcm2835_pm_of_match);
> diff --git a/include/linux/mfd/bcm2835-pm.h b/include/linux/mfd/bcm2835-pm.h
> index ed37dc40e82a..f70a810c55f7 100644
> --- a/include/linux/mfd/bcm2835-pm.h
> +++ b/include/linux/mfd/bcm2835-pm.h
> @@ -9,6 +9,7 @@ struct bcm2835_pm {
>  	struct device *dev;
>  	void __iomem *base;
>  	void __iomem *asb;
> +	void __iomem *rpivid_asb;
>  };
>  
>  #endif /* BCM2835_MFD_PM_H */

-- 
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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