Re: [PATCH 4/7] HID: multitouch: add handling for pen in dual-sensors device

["Henrik Rydberg" <rydberg@euromail.se>]

Hi Benjamin,

> Dual sensors devices reports pen and touch on two different reports.
> Using the quirk HID_QUIRK_MULTI_INPUT allows us to create a new input
> device to forward pen events.
> 
> The quirk HID_QUIRK_NO_EMPTY_INPUT avoids the creation of input devices
> for the not used mouse emulation present on Win7 certified devices.
> 
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> ---
>  drivers/hid/hid-multitouch.c | 55 ++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 51 insertions(+), 4 deletions(-)

I like the approach, it is indeed quite simple. Some comment below, though.

> 
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index 315500c..77ba751 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -100,6 +100,7 @@ struct mt_device {
>  	unsigned last_field_index;	/* last field index of the report */
>  	unsigned last_slot_field;	/* the last field of a slot */
>  	unsigned mt_report_id;	/* the report ID of the multitouch device */
> +	unsigned pen_report_id;	/* the report ID of the pen device */
>  	__s8 inputmode;		/* InputMode HID feature, -1 if non-existent */
>  	__s8 inputmode_index;	/* InputMode HID feature index in the report */
>  	__s8 maxcontact_report_id;	/* Maximum Contact Number HID feature,
> @@ -365,6 +366,35 @@ static void mt_store_field(struct hid_usage *usage, struct mt_device *td,
>  	f->usages[f->length++] = usage->hid;
>  }
>  
> +static int mt_pen_input_mapping(struct hid_device *hdev, struct hid_input *hi,
> +		struct hid_field *field, struct hid_usage *usage,
> +		unsigned long **bit, int *max)
> +{
> +	struct mt_device *td = hid_get_drvdata(hdev);
> +
> +	td->pen_report_id = field->report->id;
> +
> +	return 0;
> +}
> +
> +static int mt_pen_input_mapped(struct hid_device *hdev, struct hid_input *hi,
> +		struct hid_field *field, struct hid_usage *usage,
> +		unsigned long **bit, int *max)
> +{
> +	return 0;
> +}
> +
> +static int mt_pen_event(struct hid_device *hid, struct hid_field *field,
> +				struct hid_usage *usage, __s32 value)
> +{
> +	/* let hid-input handle it */
> +	return 0;
> +}
> +
> +static void mt_pen_report(struct hid_device *hid, struct hid_report *report)
> +{
> +}

Should the next patch not go in here directly?

> +
>  static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>  		struct hid_field *field, struct hid_usage *usage,
>  		unsigned long **bit, int *max)
> @@ -725,14 +755,12 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>  	* We need to ignore fields that belong to other collections
>  	* such as Mouse that might have the same GenericDesktop usages. */
>  	if (field->application != HID_DG_TOUCHSCREEN &&
> +	    field->application != HID_DG_PEN &&
>  	    field->application != HID_DG_TOUCHPAD)
>  		return -1;
>  
> -	/* eGalax devices provide a Digitizer.Stylus input which overrides
> -	 * the correct Digitizers.Finger X/Y ranges.
> -	 * Let's just ignore this input. */
>  	if (field->physical == HID_DG_STYLUS)
> -		return -1;
> +		return mt_pen_input_mapping(hdev, hi, field, usage, bit, max);
>  
>  	return mt_touch_input_mapping(hdev, hi, field, usage, bit, max);
>  }
> @@ -741,6 +769,9 @@ static int mt_input_mapped(struct hid_device *hdev, struct hid_input *hi,
>  		struct hid_field *field, struct hid_usage *usage,
>  		unsigned long **bit, int *max)
>  {
> +	if (field->physical == HID_DG_STYLUS)
> +		return mt_pen_input_mapped(hdev, hi, field, usage, bit, max);
> +
>  	return mt_touch_input_mapped(hdev, hi, field, usage, bit, max);
>  }
>  
> @@ -752,6 +783,9 @@ static int mt_event(struct hid_device *hid, struct hid_field *field,
>  	if (field->report->id == td->mt_report_id)
>  		return mt_touch_event(hid, field, usage, value);
>  
> +	if (field->report->id == td->pen_report_id)
> +		return mt_pen_event(hid, field, usage, value);
> +
>  	/* ignore other reports */
>  	return 1;
>  }
> @@ -765,6 +799,9 @@ static void mt_report(struct hid_device *hid, struct hid_report *report)
>  
>  	if (report->id == td->mt_report_id)
>  		mt_touch_report(hid, report);
> +
> +	if (report->id == td->pen_report_id)
> +		mt_pen_report(hid, report);
>  }
>  
>  static void mt_set_input_mode(struct hid_device *hdev)
> @@ -887,6 +924,14 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>  	 */
>  	hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;
>  
> +	/*
> +	 * This allows the driver to handle different input sensors
> +	 * that emits events through different reports on the same HID
> +	 * device.
> +	 */
> +	hdev->quirks |= HID_QUIRK_MULTI_INPUT;
> +	hdev->quirks |= HID_QUIRK_NO_EMPTY_INPUT;

I seem to recall problem with MULTI_INPUT on some devices. Should
these not be turned on based on the device type?

> +
>  	td = kzalloc(sizeof(struct mt_device), GFP_KERNEL);
>  	if (!td) {
>  		dev_err(&hdev->dev, "cannot allocate multitouch data\n");
> @@ -896,6 +941,8 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>  	td->inputmode = -1;
>  	td->maxcontact_report_id = -1;
>  	td->cc_index = -1;
> +	td->mt_report_id = -1;
> +	td->pen_report_id = -1;
>  	hid_set_drvdata(hdev, td);
>  
>  	td->fields = kzalloc(sizeof(struct mt_fields), GFP_KERNEL);
> -- 
> 1.8.1.2
> 

Thanks,
Henrik