Re: [PATCH v3 3/4] hid-logitech-hidpp: add support for high res wheel

[Benjamin Tissoires <benjamin.tissoires@redhat.com>]

Hi Mauro,

On Apr 07 2017 or thereabouts, Mauro Carvalho Chehab wrote:
> Some Logitech mouses (MX Anyware 2 and MX Master) have support
> for a high-resolution wheel.
> 
> This wheel can work in backward-compatible mode, generating
> wheel events via HID normal events, or it can use new
> HID++ events that report not only the wheel movement, but also
> the resolution.
> 
> Add support for it.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
> ---

Please rebase the patch on top of the HID tree 'for-next' branch:
https://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid.git/

>  drivers/hid/hid-logitech-hidpp.c | 199 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 199 insertions(+)
> 
> diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
> index 2e2515a4c070..c208a5107511 100644
> --- a/drivers/hid/hid-logitech-hidpp.c
> +++ b/drivers/hid/hid-logitech-hidpp.c
> @@ -62,6 +62,7 @@ MODULE_PARM_DESC(disable_tap_to_click,
>  #define HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS	BIT(22)
>  #define HIDPP_QUIRK_NO_HIDINPUT			BIT(23)
>  #define HIDPP_QUIRK_FORCE_OUTPUT_REPORTS	BIT(24)
> +#define HIDPP_QUIRK_HIRES_SCROLL		BIT(25)

There has been some addition in the HID tree there, so you'll need to
change the value.

>  
>  #define HIDPP_QUIRK_DELAYED_INIT		(HIDPP_QUIRK_NO_HIDINPUT | \
>  						 HIDPP_QUIRK_CONNECT_EVENTS)
> @@ -1361,6 +1362,67 @@ static int hidpp_ff_deinit(struct hid_device *hid)
>  	return 0;
>  }
>  
> +/* -------------------------------------------------------------------------- */
> +/* 0x2121: High Resolution Wheel                                              */
> +/* -------------------------------------------------------------------------- */
> +
> +#define HIDPP_HIGH_RES_WHEEL		0x2121
> +
> +#define CMD_MOUSE_SET_WHEEL_MODE	0x20
> +#define CMD_MOUSE_GET_WHEEL_RATCHET	0x30
> +
> +struct high_res_wheel_data {
> +	u8 feature_index;
> +	struct input_dev *input;
> +	bool ratchet;
> +};
> +
> +/**
> + * hidpp_mouse_set_wheel_mode - Sets high resolution wheel mode
> + *
> + * @invert:	if true, inverts wheel movement
> + * @high_res:	if true, wheel is in high-resolution mode. Otherwise, low res
> + * @hidpp:	if true, report wheel events via HID++ notification. If false,
> + *		use standard HID events
> + */
> +static int hidpp_mouse_set_wheel_mode(struct hidpp_device *hidpp,
> +				      bool invert,
> +				      bool high_res,
> +				      bool hidpp_mode)
> +{
> +	struct high_res_wheel_data *hrd = hidpp->private_data;
> +	u8 feature_type;
> +	struct hidpp_report response;
> +	int ret;
> +	u8 params[16] = { 0 };
> +
> +	if (!hrd->feature_index) {
> +		ret = hidpp_root_get_feature(hidpp,
> +					    HIDPP_HIGH_RES_WHEEL,
> +					    &hrd->feature_index,
> +					    &feature_type);
> +		if (ret)
> +			/* means that the device is not powered up */
> +			return ret;
> +	}
> +
> +	params[0] = invert     ? 0x4 : 0  |
> +		    high_res   ? 0x2 : 0  |
> +		    hidpp_mode ? 0x1 : 0;

It took me a while, but I finally understood why the behavior was not
working properly. I ended up adding braces (and use of BIT macro):
	params[0] = (invert     ? BIT(2) : 0)  |
		    (high_res   ? BIT(1) : 0)  |
		    (hidpp_mode ? BIT(0) : 0);

> +
> +	ret = hidpp_send_fap_command_sync(hidpp, hrd->feature_index,
> +					  CMD_MOUSE_SET_WHEEL_MODE,
> +					  params, 16, &response);

No need to send 16 parameters when only one is used. Replacing 16 by 1
just works.

> +	if (ret > 0) {
> +		hid_err(hidpp->hid_dev, "%s: received protocol error 0x%02x\n",
> +			__func__, ret);
> +		return -EPROTO;
> +	}
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
>  
>  /* ************************************************************************** */
>  /*                                                                            */
> @@ -1816,6 +1878,119 @@ static int m560_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>  }
>  
>  /* ------------------------------------------------------------------------- */
> +/* Logitech mouse devices with high resolution wheel                         */
> +/* ------------------------------------------------------------------------- */
> +
> +static int high_res_raw_event(struct hid_device *hdev, u8 *data, int size)
> +{
> +	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
> +	struct high_res_wheel_data *hrd = hidpp->private_data;
> +
> +	/* Don't handle special raw events before setting feature_index */
> +	if (!hrd || !hrd->feature_index)
> +		return 0;
> +
> +	if (data[0] != REPORT_ID_HIDPP_LONG ||
> +	    data[2] != hrd->feature_index)
> +		return 1;
> +
> +	if (size < 8) {
> +		hid_err(hdev, "error in report: size = %d: %*ph\n", size,
> +			size, data);
> +		return 0;
> +	}
> +
> +	/*
> +	 * high res wheel mouse events
> +	 *
> +	 * Wheel movement events are like:
> +	 *
> +	 * 11 03 0b 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00
> +	 *
> +	 * data[0] = 0x11
> +	 * data[1] = device-id
> +	 * data[2] = feature index (0b)
> +	 * data[3] = event type: 0x00 - wheel movement
> +	 * data[4] = bitmask:
> +	 *		bits 0-3: number of sampling periods combined
> +	 *		bit 4:
> +	 *			0 = low resolution
> +	 *			1 = high resolution
> +	 * data[5] - deltaV MSB
> +	 * data[6] = deltaV LSB
> +	 * Remaining payload is reserved
> +	 *
> +	 * Ratchet events are like:
> +	 * 11 03 0b 10 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> +	 *
> +	 * data[0] = 0x11
> +	 * data[1] = device-id
> +	 * data[2] = feature index
> +	 * data[3] = event type: 0x10 - ratchet state
> +	 * data[4] = bit 0:
> +	 *		1 = ratchet
> +	 *		0 = free wheel
> +	 * Remaining payload is reserved
> +	 */
> +
> +	if (data[3] == 0) {
> +		s16 delta = data[6] | data[5] << 8;
> +		bool res = data[4] & 0x10;
> +
> +		/*
> +		 * Report high-resolution events as REL_HWHEEL and
> +		 * low-resolution events as REL_WHEEL.
> +		 */
> +		if (res)
> +			input_report_rel(hrd->input, REL_HIRES_WHEEL, delta);
> +		else
> +			input_report_rel(hrd->input, REL_WHEEL, delta);
> +	}
> +
> +	/* FIXME: also report ratchet events to userspace */
> +
> +	return 1;
> +}
> +
> +static void high_res_populate_input(struct hidpp_device *hidpp,
> +		struct input_dev *input_dev, bool origin_is_hid_core)
> +{
> +	struct high_res_wheel_data *hrd = hidpp->private_data;
> +
> +	hrd->input = input_dev;
> +
> +	__set_bit(REL_WHEEL, hrd->input->relbit);
> +	__set_bit(REL_HIRES_WHEEL, hrd->input->relbit);
> +}
> +
> +
> +static int high_res_allocate(struct hid_device *hdev)
> +{
> +	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
> +	struct high_res_wheel_data *hrd;
> +
> +	hrd = devm_kzalloc(&hdev->dev, sizeof(struct high_res_wheel_data),
> +			GFP_KERNEL);
> +	if (!hrd)
> +		return -ENOMEM;
> +
> +	hidpp->private_data = hrd;
> +
> +	return 0;
> +};
> +
> +static int high_res_connect(struct hid_device *hdev, bool connected)
> +{
> +	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
> +
> +	if (!connected)
> +		return 0;
> +
> +	/* Enable HID++ wheel event output mode */
> +	return hidpp_mouse_set_wheel_mode(hidpp, false, false, true);
> +}
> +
> +/* ------------------------------------------------------------------------- */
>  /* Logitech K400 devices                                                     */
>  /* ------------------------------------------------------------------------- */
>  
> @@ -1955,6 +2130,9 @@ static void hidpp_populate_input(struct hidpp_device *hidpp,
>  		wtp_populate_input(hidpp, input, origin_is_hid_core);
>  	else if (hidpp->quirks & HIDPP_QUIRK_CLASS_M560)
>  		m560_populate_input(hidpp, input, origin_is_hid_core);
> +	else if (hidpp->quirks & HIDPP_QUIRK_HIRES_SCROLL)
> +		high_res_populate_input(hidpp, input, origin_is_hid_core);
> +
>  }
>  
>  static int hidpp_input_configured(struct hid_device *hdev,
> @@ -2054,6 +2232,8 @@ static int hidpp_raw_event(struct hid_device *hdev, struct hid_report *report,
>  		return wtp_raw_event(hdev, data, size);
>  	else if (hidpp->quirks & HIDPP_QUIRK_CLASS_M560)
>  		return m560_raw_event(hdev, data, size);
> +	else if (hidpp->quirks & HIDPP_QUIRK_HIRES_SCROLL)
> +		return high_res_raw_event(hdev, data, size);
>  
>  	return 0;
>  }
> @@ -2141,6 +2321,10 @@ static void hidpp_connect_event(struct hidpp_device *hidpp)
>  		ret = k400_connect(hdev, connected);
>  		if (ret)
>  			return;
> +	} else if (hidpp->quirks & HIDPP_QUIRK_HIRES_SCROLL) {
> +		ret = high_res_connect(hdev, connected);
> +		if (ret)
> +			return;
>  	}
>  
>  	if (!connected || hidpp->delayed_input)
> @@ -2215,6 +2399,7 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
>  		hidpp->quirks &= ~HIDPP_QUIRK_CLASS_WTP;
>  		hidpp->quirks &= ~HIDPP_QUIRK_CONNECT_EVENTS;
>  		hidpp->quirks &= ~HIDPP_QUIRK_NO_HIDINPUT;
> +		hidpp->quirks &= ~HIDPP_QUIRK_HIRES_SCROLL;
>  	}
>  
>  	if (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP) {
> @@ -2229,6 +2414,10 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
>  		ret = k400_allocate(hdev);
>  		if (ret)
>  			goto allocate_fail;
> +	} else if (hidpp->quirks & HIDPP_QUIRK_HIRES_SCROLL) {
> +		ret = high_res_allocate(hdev);
> +		if (ret)
> +			goto allocate_fail;
>  	}
>  
>  	INIT_WORK(&hidpp->work, delayed_work_cb);
> @@ -2354,6 +2543,16 @@ static const struct hid_device_id hidpp_devices[] = {
>  	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
>  		USB_VENDOR_ID_LOGITECH, 0x402d),
>  	  .driver_data = HIDPP_QUIRK_DELAYED_INIT | HIDPP_QUIRK_CLASS_M560 },
> +	{ /* Logitech MX Master with high resolution scroll */
> +	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
> +		USB_VENDOR_ID_LOGITECH, 0x4041),
> +	  .driver_data = HIDPP_QUIRK_CONNECT_EVENTS |

HIDPP_QUIRK_CONNECT_EVENTS is now applied by default, so there is no
need to add it.

> +			 HIDPP_QUIRK_HIRES_SCROLL },
> +	{ /* Logitech MX Anywhere 2 with high resolution scroll */
> +	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
> +		USB_VENDOR_ID_LOGITECH, 0x404a),
> +	  .driver_data = HIDPP_QUIRK_CONNECT_EVENTS |
> +			 HIDPP_QUIRK_HIRES_SCROLL },
>  	{ /* Keyboard logitech K400 */
>  	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
>  		USB_VENDOR_ID_LOGITECH, 0x4024),
> -- 
> 2.9.3
> 

Cheers,
Benjamin