linux-kernel - Re: [PATCH v2 1/2] platform/x86: hp-wmi: Add HP WMI camera switch

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Message-ID: <7a3a2c7b-5302-6c56-270c-69c811368118@redhat.com>
Date:   Wed, 26 Apr 2023 18:06:44 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Jonathan Singer <jes965@....edu>,
        Mario Limonciello <Mario.Limonciello@....com>,
        Mark Gross <markgross@...nel.org>
Cc:     Jorge Lopez <jorge.lopez2@...com>,
        Rishit Bansal <rishitbansal0@...il.com>,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
        Kai-Heng Feng <kai.heng.feng@...onical.com>
Subject: Re: [PATCH v2 1/2] platform/x86: hp-wmi: Add HP WMI camera switch

Hi Jonathan,

On 4/26/23 17:21, Jonathan Singer wrote:
> Previously, when the camera toggle switch was hit, the hp-wmi driver
> would report an invalid event code. By adding a case for that in the
> event handling switch statement we can eliminate that error code and
> enable a framework for potential further kernel handling of that key.
> This change was tested on my HP Envy x360 15-ey0023dx laptop, but it
> would likely work for any HP laptop with a camera toggle button. Now
> we emit an SW_CAMERA_LENS_COVER event, on a device that gets created
> on the first such event so as to not report incorrectly the state of
> the camera shutter before we can know its state.
> 
> Signed-off-by: Jonathan Singer <jes965@....edu>
> ---
>  drivers/platform/x86/hp/hp-wmi.c | 50 ++++++++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
> 
> diff --git a/drivers/platform/x86/hp/hp-wmi.c b/drivers/platform/x86/hp/hp-wmi.c
> index 873f59c3e280..a7fb33ac49b8 100644
> --- a/drivers/platform/x86/hp/hp-wmi.c
> +++ b/drivers/platform/x86/hp/hp-wmi.c
> @@ -90,6 +90,7 @@ enum hp_wmi_event_ids {
>  	HPWMI_PEAKSHIFT_PERIOD		= 0x0F,
>  	HPWMI_BATTERY_CHARGE_PERIOD	= 0x10,
>  	HPWMI_SANITIZATION_MODE		= 0x17,
> +	HPWMI_CAMERA_TOGGLE		= 0x1A,
>  	HPWMI_OMEN_KEY			= 0x1D,
>  	HPWMI_SMART_EXPERIENCE_APP	= 0x21,
>  };
> @@ -228,6 +229,7 @@ static const struct key_entry hp_wmi_keymap[] = {
>  };
>  
>  static struct input_dev *hp_wmi_input_dev;
> +static struct input_dev *camera_shutter_input_dev;
>  static struct platform_device *hp_wmi_platform_dev;
>  static struct platform_profile_handler platform_profile_handler;
>  static bool platform_profile_support;
> @@ -739,6 +741,36 @@ static ssize_t postcode_store(struct device *dev, struct device_attribute *attr,
>  	return count;
>  }
>  
> +static int camera_shutter_input_setup(void)
> +{
> +	int err;
> +
> +	camera_shutter_input_dev = input_allocate_device();
> +	if (!camera_shutter_input_dev)
> +		return -ENOMEM;
> +
> +	camera_shutter_input_dev->name = "HP WMI camera shutter";
> +	camera_shutter_input_dev->phys = "wmi/input1";
> +	camera_shutter_input_dev->id.bustype = BUS_HOST;
> +
> +	__set_bit(EV_SW, camera_shutter_input_dev->evbit);
> +	__set_bit(SW_CAMERA_LENS_COVER, camera_shutter_input_dev->swbit);
> +
> +	/* Set initial hardware state */
> +	input_sync(camera_shutter_input_dev);

This initial sync is only necessary if you have actually
read + set an initial state, which is not happening here,
so please drop this.

The caller of camera_shutter_input_setup() will set
a state + call input_sync() immediately afterwards anyways,
so there is no need to set an initial state.

Otherwise this looks good to me, thank you for working on this.

Regards,

Hans


> +
> +	err = input_register_device(camera_shutter_input_dev);
> +	if (err)
> +		goto err_free_dev;
> +
> +	return 0;
> +
> + err_free_dev:
> +	input_free_device(camera_shutter_input_dev);
> +	camera_shutter_input_dev = NULL;
> +	return err;
> +}
> +
>  static DEVICE_ATTR_RO(display);
>  static DEVICE_ATTR_RO(hddtemp);
>  static DEVICE_ATTR_RW(als);
> @@ -866,6 +898,20 @@ static void hp_wmi_notify(u32 value, void *context)
>  		break;
>  	case HPWMI_SANITIZATION_MODE:
>  		break;
> +	case HPWMI_CAMERA_TOGGLE:
> +		if (!camera_shutter_input_dev)
> +			if (camera_shutter_input_setup()) {
> +				pr_info("Failed to setup camera shutter input device\n");
> +				break;
> +			}
> +		if (event_data == 0xff)
> +			input_report_switch(camera_shutter_input_dev, SW_CAMERA_LENS_COVER, 1);
> +		else if (event_data == 0xfe)
> +			input_report_switch(camera_shutter_input_dev, SW_CAMERA_LENS_COVER, 0);
> +		else
> +			pr_info("Unknown camera shutter state - 0x%x\n", event_data);
> +		input_sync(camera_shutter_input_dev);
> +		break;
>  	case HPWMI_SMART_EXPERIENCE_APP:
>  		break;
>  	default:
> @@ -1564,9 +1610,13 @@ static void __exit hp_wmi_exit(void)
>  	if (wmi_has_guid(HPWMI_EVENT_GUID))
>  		hp_wmi_input_destroy();
>  
> +	if (camera_shutter_input_dev)
> +		input_unregister_device(camera_shutter_input_dev);
> +
>  	if (hp_wmi_platform_dev) {
>  		platform_device_unregister(hp_wmi_platform_dev);
>  		platform_driver_unregister(&hp_wmi_driver);
>  	}
> +
>  }
>  module_exit(hp_wmi_exit);