linux-kernel - Re: [PATCH v3 3/3] ACPI / PMIC: AXP288: support virtual GPIO in ACPI table

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Date:	Mon, 24 Nov 2014 02:06:05 +0100
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Aaron Lu <aaron.lu@...el.com>
Cc:	Lee Jones <lee.jones@...aro.org>,
	Jacob Pan <jacob.jun.pan@...ux.intel.com>,
	Yegnesh Iyer <yegnesh.s.iyer@...el.com>,
	linux-acpi@...r.kernel.org, linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/3] ACPI / PMIC: AXP288: support virtual GPIO in ACPI table

On Friday, November 21, 2014 03:11:51 PM Aaron Lu wrote:
> The same virtual GPIO strategy is also used for the AXP288 PMIC in that
> various control methods that are used to do power rail handling and
> sensor reading/setting will touch GPIO fields defined under the PMIC
> device. The GPIO fileds are only defined by the ACPI code while the
> actual hardware doesn't really have a GPIO controller, but to make those
> control method execution succeed, we have to install a GPIO handler for
> the PMIC device handle. Since we do not need the virtual GPIO strategy,
> we can simply do nothing in that handler.
> 
> Signed-off-by: Aaron Lu <aaron.lu@...el.com>
> ---
>  drivers/acpi/pmic/intel_pmic_xpower.c | 27 +++++++++++++++++++++++----
>  1 file changed, 23 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/acpi/pmic/intel_pmic_xpower.c b/drivers/acpi/pmic/intel_pmic_xpower.c
> index 6c4d6ce0cff1..480c41c36444 100644
> --- a/drivers/acpi/pmic/intel_pmic_xpower.c
> +++ b/drivers/acpi/pmic/intel_pmic_xpower.c
> @@ -251,13 +251,32 @@ static struct intel_pmic_opregion_data intel_xpower_pmic_opregion_data = {
>  	.thermal_table_count = ARRAY_SIZE(thermal_table),
>  };
>  
> +static acpi_status intel_xpower_pmic_gpio_handler(u32 function,
> +		acpi_physical_address address, u32 bit_width, u64 *value,
> +		void *handler_context, void *region_context)
> +{
> +	return AE_OK;
> +}
>  
>  static int intel_xpower_pmic_opregion_probe(struct platform_device *pdev)
>  {
> -	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
> -	return intel_pmic_install_opregion_handler(&pdev->dev,
> -			ACPI_HANDLE(pdev->dev.parent), axp20x->regmap,
> -			&intel_xpower_pmic_opregion_data);
> +	struct device *parent = pdev->dev.parent;
> +	struct axp20x_dev *axp20x = dev_get_drvdata(parent);
> +	acpi_status status;
> +	int result;
> +
> +	result = intel_pmic_install_opregion_handler(&pdev->dev,
> +					ACPI_HANDLE(parent), axp20x->regmap,
> +					&intel_xpower_pmic_opregion_data);
> +	if (!result) {
> +		status = acpi_install_address_space_handler(
> +				ACPI_HANDLE(parent), ACPI_ADR_SPACE_GPIO,
> +				intel_xpower_pmic_gpio_handler, NULL, NULL);

So here we have a problem, because we can't unregister the opregion handler
registered above if this fails.  Not nice.

> +		if (ACPI_FAILURE(status))
> +			result = -ENODEV;
> +	}
> +
> +	return result;
>  }
>  
>  static struct platform_driver intel_xpower_pmic_opregion_driver = {
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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