Re: [PATCH RESEND 09/13] platform/chrome: cros_ec_lpc: Add MKBP events support over ACPI

[Benson Leung <bleung@google.com>]

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Hi Enric and Thierry,

Just one minor question about this commit.

On Tue, May 16, 2017 at 06:13:15PM +0200, Enric Balletbo i Serra wrote:
> From: Gwendal Grignou <gwendal@chromium.org>
> 
> This patch installs a notify handler to process MKBP events for EC
> firmware directing them over ACPI.
> 
> Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
> Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
> ---
>  drivers/platform/chrome/cros_ec_lpc.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
> index 89afad7..eeb187e 100644
> --- a/drivers/platform/chrome/cros_ec_lpc.c
> +++ b/drivers/platform/chrome/cros_ec_lpc.c
> @@ -227,9 +227,20 @@ static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset,
>  	return cnt;
>  }
>  
> +static void cros_ec_lpc_acpi_notify(acpi_handle device, u32 value, void *data)
> +{
> +	struct cros_ec_device *ec_dev = data;
> +
> +	if (ec_dev->mkbp_event_supported && cros_ec_get_next_event(ec_dev) > 0)
> +		blocking_notifier_call_chain(&ec_dev->event_notifier, 0,
> +					     ec_dev);
> +}
> +
>  static int cros_ec_lpc_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> +	struct acpi_device *adev;
> +	acpi_status status;
>  	struct cros_ec_device *ec_dev;
>  	u8 buf[2];
>  	int ret;
> @@ -277,12 +288,33 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> +	/*
> +	 * Connect a notify handler to process MKBP messages if we have a
> +	 * companion ACPI device.
> +	 */
> +	adev = ACPI_COMPANION(dev);
> +	if (adev) {
> +		status = acpi_install_notify_handler(adev->handle,
> +						     ACPI_ALL_NOTIFY,

Is there a reason you're using ACPI_ALL_NOTIFY here instead of
ACPI_SYSTEM_NOTIFY that is done in the CHROMIUM version of this?

> +						     cros_ec_lpc_acpi_notify,
> +						     ec_dev);
> +		if (ACPI_FAILURE(status))
> +			dev_warn(dev, "Failed to register notifier %08x\n",
> +				 status);
> +	}
> +
>  	return 0;
>  }
>  
>  static int cros_ec_lpc_remove(struct platform_device *pdev)
>  {
>  	struct cros_ec_device *ec_dev;
> +	struct acpi_device *adev;
> +
> +	adev = ACPI_COMPANION(&pdev->dev);
> +	if (adev)
> +		acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
> +					   cros_ec_lpc_acpi_notify);
>  
>  	ec_dev = platform_get_drvdata(pdev);
>  	cros_ec_remove(ec_dev);
> -- 
> 2.9.3
> 

-- 
Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
bleung@google.com
Chromium OS Project
bleung@chromium.org

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