[PATCH v2 0/5] Add support for high-resolution scrolling on Logitech mice

[PATCH v2 0/5] Add support for high-resolution scrolling on Logitech mice

[Harry Cutts]

Hi everyone,

This is v2 of the patch set adding support for high-resolution scroll
wheels on Logitech mice. See the linux-input "Reporting high-resolution
scroll events" thread [0] for previous discussion of the evdev changes.
I would love to hear your feedback.

Thanks,

Harry Cutts
Chrome OS Touch/Input team

[0]: https://www.spinics.net/lists/linux-input/msg57380.html


Changes in v2:
* Changed the REL_WHEEL_HI_RES code to use micrometres (a.k.a. microns)
  as its units, instead of 256ths of a millimetre.
* Removed support for mice connecting over Bluetooth, due to a bug where
  the mouse's high-res mode and the driver's settings get out of sync
  when the mouse is power cycled.
* Moved the creation of the HID++ 1.0 function and the refactor to use
  the LDJ_DEVICE macro into separate patches.
* Added a couple of explanatory comments to the Logitech driver.

Harry Cutts (5):
  Add the `REL_WHEEL_HI_RES` event code
  Create a utility class for counting scroll events
  Add function to enable HID++ 1.0 "scrolling acceleration"
  Enable high-resolution scrolling on Logitech mice
  Use LDJ_DEVICE macro for existing Logitech mice

 Documentation/input/event-codes.rst    |  11 +-
 drivers/hid/hid-input.c                |  45 ++++
 drivers/hid/hid-logitech-hidpp.c       | 311 ++++++++++++++++++++++---
 include/linux/hid.h                    |  28 +++
 include/uapi/linux/input-event-codes.h |   1 +
 5 files changed, 368 insertions(+), 28 deletions(-)

-- 
2.19.0.rc0.228.g281dcd1b4d0-goog

[PATCH v2 1/5] Add the `REL_WHEEL_HI_RES` event code

[Harry Cutts]

This event code represents scroll reports from high-resolution wheels,
and will be used by future patches in this series. See the linux-input
"Reporting high-resolution scroll events" thread [0] for more details.

[0]: https://www.spinics.net/lists/linux-input/msg57380.html

Signed-off-by: Harry Cutts <hcutts@chromium.org>
---

Changes in v2: None

 Documentation/input/event-codes.rst    | 11 ++++++++++-
 include/uapi/linux/input-event-codes.h |  1 +
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/Documentation/input/event-codes.rst b/Documentation/input/event-codes.rst
index a8c0873beb95..cef220c176a4 100644
--- a/Documentation/input/event-codes.rst
+++ b/Documentation/input/event-codes.rst
@@ -190,7 +190,16 @@ A few EV_REL codes have special meanings:
 * REL_WHEEL, REL_HWHEEL:
 
   - These codes are used for vertical and horizontal scroll wheels,
-    respectively.
+    respectively. The value is the number of "notches" moved on the wheel, the
+    physical size of which varies by device. For high-resolution wheels (which
+    report multiple events for each notch of movement, or do not have notches)
+    this may be an approximation based on the high-resolution scroll events.
+
+* REL_WHEEL_HI_RES:
+
+  - If a vertical scroll wheel supports high-resolution scrolling, this code
+    will be emitted in addition to REL_WHEEL. The value is the (approximate)
+    distance travelled by the user's finger, in microns.
 
 EV_ABS
 ------
diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h
index 53fbae27b280..dad8d3890a3a 100644
--- a/include/uapi/linux/input-event-codes.h
+++ b/include/uapi/linux/input-event-codes.h
@@ -708,6 +708,7 @@
 #define REL_DIAL		0x07
 #define REL_WHEEL		0x08
 #define REL_MISC		0x09
+#define REL_WHEEL_HI_RES	0x0a
 #define REL_MAX			0x0f
 #define REL_CNT			(REL_MAX+1)
 
-- 
2.19.0.rc0.228.g281dcd1b4d0-goog

Re: [PATCH v2 1/5] Add the `REL_WHEEL_HI_RES` event code

[Jiri Kosina]

On Thu, 30 Aug 2018, Harry Cutts wrote:

> This event code represents scroll reports from high-resolution wheels,
> and will be used by future patches in this series. See the linux-input
> "Reporting high-resolution scroll events" thread [0] for more details.
> 
> [0]: https://www.spinics.net/lists/linux-input/msg57380.html
> 
> Signed-off-by: Harry Cutts <hcutts@chromium.org>
> ---
> 
> Changes in v2: None
> 
>  Documentation/input/event-codes.rst    | 11 ++++++++++-
>  include/uapi/linux/input-event-codes.h |  1 +
>  2 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/input/event-codes.rst b/Documentation/input/event-codes.rst
> index a8c0873beb95..cef220c176a4 100644
> --- a/Documentation/input/event-codes.rst
> +++ b/Documentation/input/event-codes.rst
> @@ -190,7 +190,16 @@ A few EV_REL codes have special meanings:
>  * REL_WHEEL, REL_HWHEEL:
>  
>    - These codes are used for vertical and horizontal scroll wheels,
> -    respectively.
> +    respectively. The value is the number of "notches" moved on the wheel, the
> +    physical size of which varies by device. For high-resolution wheels (which
> +    report multiple events for each notch of movement, or do not have notches)
> +    this may be an approximation based on the high-resolution scroll events.
> +
> +* REL_WHEEL_HI_RES:
> +
> +  - If a vertical scroll wheel supports high-resolution scrolling, this code
> +    will be emitted in addition to REL_WHEEL. The value is the (approximate)
> +    distance travelled by the user's finger, in microns.
>  
>  EV_ABS
>  ------
> diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h
> index 53fbae27b280..dad8d3890a3a 100644
> --- a/include/uapi/linux/input-event-codes.h
> +++ b/include/uapi/linux/input-event-codes.h
> @@ -708,6 +708,7 @@
>  #define REL_DIAL		0x07
>  #define REL_WHEEL		0x08
>  #define REL_MISC		0x09
> +#define REL_WHEEL_HI_RES	0x0a
>  #define REL_MAX			0x0f
>  #define REL_CNT			(REL_MAX+1)

Dmitry, is this OK with you?

Thanks,

-- 
Jiri Kosina
SUSE Labs

Re: [PATCH v2 1/5] Add the `REL_WHEEL_HI_RES` event code

[Dmitry Torokhov]

On Mon, Sep 03, 2018 at 03:43:13PM +0200, Jiri Kosina wrote:
> On Thu, 30 Aug 2018, Harry Cutts wrote:
> 
> > This event code represents scroll reports from high-resolution wheels,
> > and will be used by future patches in this series. See the linux-input
> > "Reporting high-resolution scroll events" thread [0] for more details.
> > 
> > [0]: https://www.spinics.net/lists/linux-input/msg57380.html
> > 
> > Signed-off-by: Harry Cutts <hcutts@chromium.org>
> > ---
> > 
> > Changes in v2: None
> > 
> >  Documentation/input/event-codes.rst    | 11 ++++++++++-
> >  include/uapi/linux/input-event-codes.h |  1 +
> >  2 files changed, 11 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/input/event-codes.rst b/Documentation/input/event-codes.rst
> > index a8c0873beb95..cef220c176a4 100644
> > --- a/Documentation/input/event-codes.rst
> > +++ b/Documentation/input/event-codes.rst
> > @@ -190,7 +190,16 @@ A few EV_REL codes have special meanings:
> >  * REL_WHEEL, REL_HWHEEL:
> >  
> >    - These codes are used for vertical and horizontal scroll wheels,
> > -    respectively.
> > +    respectively. The value is the number of "notches" moved on the wheel, the
> > +    physical size of which varies by device. For high-resolution wheels (which
> > +    report multiple events for each notch of movement, or do not have notches)
> > +    this may be an approximation based on the high-resolution scroll events.
> > +
> > +* REL_WHEEL_HI_RES:
> > +
> > +  - If a vertical scroll wheel supports high-resolution scrolling, this code
> > +    will be emitted in addition to REL_WHEEL. The value is the (approximate)
> > +    distance travelled by the user's finger, in microns.
> >  
> >  EV_ABS
> >  ------
> > diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h
> > index 53fbae27b280..dad8d3890a3a 100644
> > --- a/include/uapi/linux/input-event-codes.h
> > +++ b/include/uapi/linux/input-event-codes.h
> > @@ -708,6 +708,7 @@
> >  #define REL_DIAL		0x07
> >  #define REL_WHEEL		0x08
> >  #define REL_MISC		0x09
> > +#define REL_WHEEL_HI_RES	0x0a
> >  #define REL_MAX			0x0f
> >  #define REL_CNT			(REL_MAX+1)
> 
> Dmitry, is this OK with you?

Yep, please feel free to merge through your tree.

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Thanks.

-- 
Dmitry

Re: [PATCH v2 1/5] Add the `REL_WHEEL_HI_RES` event code

[Peter Hutterer]

On Thu, Aug 30, 2018 at 02:56:18PM -0700, Harry Cutts wrote:
> This event code represents scroll reports from high-resolution wheels,
> and will be used by future patches in this series. See the linux-input
> "Reporting high-resolution scroll events" thread [0] for more details.
> 
> [0]: https://www.spinics.net/lists/linux-input/msg57380.html
> 
> Signed-off-by: Harry Cutts <hcutts@chromium.org>

looks good to me, thanks. For the archives, the libinput issue filed for
this is here: https://gitlab.freedesktop.org/libinput/libinput/issues/130

Cheers,
   Peter

> ---
> 
> Changes in v2: None
> 
>  Documentation/input/event-codes.rst    | 11 ++++++++++-
>  include/uapi/linux/input-event-codes.h |  1 +
>  2 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/input/event-codes.rst b/Documentation/input/event-codes.rst
> index a8c0873beb95..cef220c176a4 100644
> --- a/Documentation/input/event-codes.rst
> +++ b/Documentation/input/event-codes.rst
> @@ -190,7 +190,16 @@ A few EV_REL codes have special meanings:
>  * REL_WHEEL, REL_HWHEEL:
>  
>    - These codes are used for vertical and horizontal scroll wheels,
> -    respectively.
> +    respectively. The value is the number of "notches" moved on the wheel, the
> +    physical size of which varies by device. For high-resolution wheels (which
> +    report multiple events for each notch of movement, or do not have notches)
> +    this may be an approximation based on the high-resolution scroll events.
> +
> +* REL_WHEEL_HI_RES:
> +
> +  - If a vertical scroll wheel supports high-resolution scrolling, this code
> +    will be emitted in addition to REL_WHEEL. The value is the (approximate)
> +    distance travelled by the user's finger, in microns.
>  
>  EV_ABS
>  ------
> diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h
> index 53fbae27b280..dad8d3890a3a 100644
> --- a/include/uapi/linux/input-event-codes.h
> +++ b/include/uapi/linux/input-event-codes.h
> @@ -708,6 +708,7 @@
>  #define REL_DIAL		0x07
>  #define REL_WHEEL		0x08
>  #define REL_MISC		0x09
> +#define REL_WHEEL_HI_RES	0x0a
>  #define REL_MAX			0x0f
>  #define REL_CNT			(REL_MAX+1)
>  
> -- 
> 2.19.0.rc0.228.g281dcd1b4d0-goog
> 

[PATCH v2 2/5] Create a utility class for counting scroll events

[Harry Cutts]

To avoid code duplication, this class counts high-resolution scroll
movements and emits the legacy low-resolution events when appropriate.
Drivers should be able to create one instance for each scroll wheel that
they need to handle.

Signed-off-by: Harry Cutts <hcutts@chromium.org>
---

Changes in v2: None

 drivers/hid/hid-input.c | 45 +++++++++++++++++++++++++++++++++++++++++
 include/linux/hid.h     | 28 +++++++++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 4e94ea3e280a..6e84e7b9afcb 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -1826,3 +1826,48 @@ void hidinput_disconnect(struct hid_device *hid)
 }
 EXPORT_SYMBOL_GPL(hidinput_disconnect);
 
+/**
+ * hid_scroll_counter_handle_scroll() - Send high- and low-resolution scroll
+ *                                      events given a high-resolution wheel
+ *                                      movement.
+ * @counter: a hid_scroll_counter struct describing the wheel.
+ * @hi_res_value: the movement of the wheel, in the mouse's high-resolution
+ *                units.
+ *
+ * Given a high-resolution movement, this function converts the movement into
+ * microns and emits high-resolution scroll events for the input device. It also
+ * uses the multiplier from &struct hid_scroll_counter to emit low-resolution
+ * scroll events when appropriate for backwards-compatibility with userspace
+ * input libraries.
+ */
+void hid_scroll_counter_handle_scroll(struct hid_scroll_counter *counter,
+				      int hi_res_value)
+{
+	int low_res_scroll_amount;
+	/* Some wheels will rest 7/8ths of a notch from the previous notch
+	 * after slow movement, so we want the threshold for low-res events to
+	 * be in the middle of the notches (e.g. after 4/8ths) as opposed to on
+	 * the notches themselves (8/8ths).
+	 */
+	int threshold = counter->resolution_multiplier / 2;
+
+	input_report_rel(counter->dev, REL_WHEEL_HI_RES,
+			 hi_res_value * counter->microns_per_hi_res_unit);
+
+	counter->remainder += hi_res_value;
+	if (abs(counter->remainder) >= threshold) {
+		/* Add (or subtract) 1 because we want to trigger when the wheel
+		 * is half-way to the next notch (i.e. scroll 1 notch after a
+		 * 1/2 notch movement, 2 notches after a 1 1/2 notch movement,
+		 * etc.).
+		 */
+		low_res_scroll_amount =
+			counter->remainder / counter->resolution_multiplier
+			+ (hi_res_value > 0 ? 1 : -1);
+		input_report_rel(counter->dev, REL_WHEEL,
+				 low_res_scroll_amount);
+		counter->remainder -=
+			low_res_scroll_amount * counter->resolution_multiplier;
+	}
+}
+EXPORT_SYMBOL_GPL(hid_scroll_counter_handle_scroll);
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 834e6461a690..037e37b0b0e6 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -1138,6 +1138,34 @@ static inline u32 hid_report_len(struct hid_report *report)
 int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
 		int interrupt);
 
+
+/**
+ * struct hid_scroll_counter - Utility class for processing high-resolution
+ *                             scroll events.
+ * @dev: the input device for which events should be reported.
+ * @microns_per_hi_res_unit: the amount moved by the user's finger for each
+ *                           high-resolution unit reported by the mouse, in
+ *                           microns.
+ * @resolution_multiplier: the wheel's resolution in high-resolution mode as a
+ *                         multiple of its lower resolution. For example, if
+ *                         moving the wheel by one "notch" would result in a
+ *                         value of 1 in low-resolution mode but 8 in
+ *                         high-resolution, the multiplier is 8.
+ * @remainder: counts the number of high-resolution units moved since the last
+ *             low-resolution event (REL_WHEEL or REL_HWHEEL) was sent. Should
+ *             only be used by class methods.
+ */
+struct hid_scroll_counter {
+	struct input_dev *dev;
+	int microns_per_hi_res_unit;
+	int resolution_multiplier;
+
+	int remainder;
+};
+
+void hid_scroll_counter_handle_scroll(struct hid_scroll_counter *counter,
+				      int hi_res_value);
+
 /* HID quirks API */
 unsigned long hid_lookup_quirk(const struct hid_device *hdev);
 int hid_quirks_init(char **quirks_param, __u16 bus, int count);
-- 
2.19.0.rc0.228.g281dcd1b4d0-goog

[PATCH v2 3/5] Add function to enable HID++ 1.0 "scrolling acceleration"

[Harry Cutts]

"Scrolling acceleration" is a bit of a misnomer: it doesn't deal with
acceleration at all. However, that's the name used in Logitech's spec,
so I used it here.

Signed-off-by: Harry Cutts <hcutts@chromium.org>
---

Changes in v2: None

 drivers/hid/hid-logitech-hidpp.c | 47 +++++++++++++++++++++++---------
 1 file changed, 34 insertions(+), 13 deletions(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 19cc980eebce..7f8218f6ff56 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -400,32 +400,53 @@ static void hidpp_prefix_name(char **name, int name_length)
 #define HIDPP_SET_LONG_REGISTER				0x82
 #define HIDPP_GET_LONG_REGISTER				0x83
 
-#define HIDPP_REG_GENERAL				0x00
-
-static int hidpp10_enable_battery_reporting(struct hidpp_device *hidpp_dev)
+/**
+ * hidpp10_set_register_bit() - Sets a single bit in a HID++ 1.0 register.
+ * @hidpp_dev: the device to set the register on.
+ * @register_address: the address of the register to modify.
+ * @byte: the byte of the register to modify. Should be less than 3.
+ * Return: 0 if successful, otherwise a negative error code.
+ */
+static int hidpp10_set_register_bit(struct hidpp_device *hidpp_dev,
+	u8 register_address, u8 byte, u8 bit)
 {
 	struct hidpp_report response;
 	int ret;
 	u8 params[3] = { 0 };
 
 	ret = hidpp_send_rap_command_sync(hidpp_dev,
-					REPORT_ID_HIDPP_SHORT,
-					HIDPP_GET_REGISTER,
-					HIDPP_REG_GENERAL,
-					NULL, 0, &response);
+					  REPORT_ID_HIDPP_SHORT,
+					  HIDPP_GET_REGISTER,
+					  register_address,
+					  NULL, 0, &response);
 	if (ret)
 		return ret;
 
 	memcpy(params, response.rap.params, 3);
 
-	/* Set the battery bit */
-	params[0] |= BIT(4);
+	params[byte] |= BIT(bit);
 
 	return hidpp_send_rap_command_sync(hidpp_dev,
-					REPORT_ID_HIDPP_SHORT,
-					HIDPP_SET_REGISTER,
-					HIDPP_REG_GENERAL,
-					params, 3, &response);
+					   REPORT_ID_HIDPP_SHORT,
+					   HIDPP_SET_REGISTER,
+					   register_address,
+					   params, 3, &response);
+}
+
+
+#define HIDPP_REG_GENERAL				0x00
+
+static int hidpp10_enable_battery_reporting(struct hidpp_device *hidpp_dev)
+{
+	return hidpp10_set_register_bit(hidpp_dev, HIDPP_REG_GENERAL, 0, 4);
+}
+
+#define HIDPP_REG_FEATURES				0x01
+
+/* On HID++ 1.0 devices, high-res scroll was called "scrolling acceleration". */
+static int hidpp10_enable_scrolling_acceleration(struct hidpp_device *hidpp_dev)
+{
+	return hidpp10_set_register_bit(hidpp_dev, HIDPP_REG_FEATURES, 0, 6);
 }
 
 #define HIDPP_REG_BATTERY_STATUS			0x07
-- 
2.19.0.rc0.228.g281dcd1b4d0-goog

[PATCH v2 4/5] Enable high-resolution scrolling on Logitech mice

[Harry Cutts]

There are three features used by various Logitech mice for
high-resolution scrolling: the scrolling acceleration bit in HID++ 1.0,
and the x2120 and x2121 features in HID++ 2.0 and above. This patch
supports all three, and uses the multiplier reported by the mouse for
the HID++ 2.0+ features.

The full list of product IDs of mice which support high-resolution
scrolling was provided by Logitech, but the patch was tested using the
following mice (using the Unifying receiver):

* HID++ 1.0: Anywhere MX, Performance MX
* x2120: M560
* x2121: MX Anywhere 2, MX Master 2S

Signed-off-by: Harry Cutts <hcutts@chromium.org>
---

Changes in v2: None

 drivers/hid/hid-logitech-hidpp.c | 249 ++++++++++++++++++++++++++++++-
 1 file changed, 245 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 7f8218f6ff56..fd6a8c325fa0 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -64,6 +64,14 @@ MODULE_PARM_DESC(disable_tap_to_click,
 #define HIDPP_QUIRK_NO_HIDINPUT			BIT(23)
 #define HIDPP_QUIRK_FORCE_OUTPUT_REPORTS	BIT(24)
 #define HIDPP_QUIRK_UNIFYING			BIT(25)
+#define HIDPP_QUIRK_HI_RES_SCROLL_1P0		BIT(26)
+#define HIDPP_QUIRK_HI_RES_SCROLL_X2120		BIT(27)
+#define HIDPP_QUIRK_HI_RES_SCROLL_X2121		BIT(28)
+
+/* Convenience constant to check for any high-res support. */
+#define HIDPP_QUIRK_HI_RES_SCROLL	(HIDPP_QUIRK_HI_RES_SCROLL_1P0 | \
+					 HIDPP_QUIRK_HI_RES_SCROLL_X2120 | \
+					 HIDPP_QUIRK_HI_RES_SCROLL_X2121)
 
 #define HIDPP_QUIRK_DELAYED_INIT		HIDPP_QUIRK_NO_HIDINPUT
 
@@ -149,6 +157,7 @@ struct hidpp_device {
 	unsigned long capabilities;
 
 	struct hidpp_battery battery;
+	struct hid_scroll_counter vertical_wheel_counter;
 };
 
 /* HID++ 1.0 error codes */
@@ -1157,6 +1166,101 @@ static int hidpp_battery_get_property(struct power_supply *psy,
 	return ret;
 }
 
+/* -------------------------------------------------------------------------- */
+/* 0x2120: Hi-resolution scrolling                                            */
+/* -------------------------------------------------------------------------- */
+
+#define HIDPP_PAGE_HI_RESOLUTION_SCROLLING			0x2120
+
+#define CMD_HI_RESOLUTION_SCROLLING_SET_HIGHRES_SCROLLING_MODE	0x10
+
+static int hidpp_hrs_set_highres_scrolling_mode(struct hidpp_device *hidpp,
+	bool enabled, u8 *multiplier)
+{
+	u8 feature_index;
+	u8 feature_type;
+	int ret;
+	u8 params[1];
+	struct hidpp_report response;
+
+	ret = hidpp_root_get_feature(hidpp,
+				     HIDPP_PAGE_HI_RESOLUTION_SCROLLING,
+				     &feature_index,
+				     &feature_type);
+	if (ret)
+		return ret;
+
+	params[0] = enabled ? BIT(0) : 0;
+	ret = hidpp_send_fap_command_sync(hidpp, feature_index,
+					  CMD_HI_RESOLUTION_SCROLLING_SET_HIGHRES_SCROLLING_MODE,
+					  params, sizeof(params), &response);
+	if (ret)
+		return ret;
+	*multiplier = response.fap.params[1];
+	return 0;
+}
+
+/* -------------------------------------------------------------------------- */
+/* 0x2121: HiRes Wheel                                                        */
+/* -------------------------------------------------------------------------- */
+
+#define HIDPP_PAGE_HIRES_WHEEL		0x2121
+
+#define CMD_HIRES_WHEEL_GET_WHEEL_CAPABILITY	0x00
+#define CMD_HIRES_WHEEL_SET_WHEEL_MODE		0x20
+
+static int hidpp_hrw_get_wheel_capability(struct hidpp_device *hidpp,
+	u8 *multiplier)
+{
+	u8 feature_index;
+	u8 feature_type;
+	int ret;
+	struct hidpp_report response;
+
+	ret = hidpp_root_get_feature(hidpp, HIDPP_PAGE_HIRES_WHEEL,
+				     &feature_index, &feature_type);
+	if (ret)
+		goto return_default;
+
+	ret = hidpp_send_fap_command_sync(hidpp, feature_index,
+					  CMD_HIRES_WHEEL_GET_WHEEL_CAPABILITY,
+					  NULL, 0, &response);
+	if (ret)
+		goto return_default;
+
+	*multiplier = response.fap.params[0];
+	return 0;
+return_default:
+	*multiplier = 8;
+	hid_warn(hidpp->hid_dev,
+		 "Couldn't get wheel multiplier (error %d), assuming %d.\n",
+		 ret, *multiplier);
+	return ret;
+}
+
+static int hidpp_hrw_set_wheel_mode(struct hidpp_device *hidpp, bool invert,
+	bool high_resolution, bool use_hidpp)
+{
+	u8 feature_index;
+	u8 feature_type;
+	int ret;
+	u8 params[1];
+	struct hidpp_report response;
+
+	ret = hidpp_root_get_feature(hidpp, HIDPP_PAGE_HIRES_WHEEL,
+				     &feature_index, &feature_type);
+	if (ret)
+		return ret;
+
+	params[0] = (invert          ? BIT(2) : 0) |
+		    (high_resolution ? BIT(1) : 0) |
+		    (use_hidpp       ? BIT(0) : 0);
+
+	return hidpp_send_fap_command_sync(hidpp, feature_index,
+					   CMD_HIRES_WHEEL_SET_WHEEL_MODE,
+					   params, sizeof(params), &response);
+}
+
 /* -------------------------------------------------------------------------- */
 /* 0x4301: Solar Keyboard                                                     */
 /* -------------------------------------------------------------------------- */
@@ -2420,7 +2524,8 @@ static int m560_raw_event(struct hid_device *hdev, u8 *data, int size)
 		input_report_rel(mydata->input, REL_Y, v);
 
 		v = hid_snto32(data[6], 8);
-		input_report_rel(mydata->input, REL_WHEEL, v);
+		hid_scroll_counter_handle_scroll(
+				&hidpp->vertical_wheel_counter, v);
 
 		input_sync(mydata->input);
 	}
@@ -2548,6 +2653,73 @@ static int g920_get_config(struct hidpp_device *hidpp)
 	return 0;
 }
 
+/* -------------------------------------------------------------------------- */
+/* High-resolution scroll wheels                                              */
+/* -------------------------------------------------------------------------- */
+
+/**
+ * struct hi_res_scroll_info - Stores info on a device's high-res scroll wheel.
+ * @product_id: the HID product ID of the device being described.
+ * @microns_per_hi_res_unit: the distance moved by the user's finger for each
+ *                         high-resolution unit reported by the device, in
+ *                         256ths of a millimetre.
+ */
+struct hi_res_scroll_info {
+	__u32 product_id;
+	int microns_per_hi_res_unit;
+};
+
+static struct hi_res_scroll_info hi_res_scroll_devices[] = {
+	{ /* Anywhere MX */
+	  .product_id = 0x1017, .microns_per_hi_res_unit = 445 },
+	{ /* Performance MX */
+	  .product_id = 0x101a, .microns_per_hi_res_unit = 406 },
+	{ /* M560 */
+	  .product_id = 0x402d, .microns_per_hi_res_unit = 435 },
+	{ /* MX Master 2S */
+	  .product_id = 0x4069, .microns_per_hi_res_unit = 406 },
+};
+
+static int hi_res_scroll_look_up_microns(__u32 product_id)
+{
+	int i;
+	int num_devices = sizeof(hi_res_scroll_devices)
+			  / sizeof(hi_res_scroll_devices[0]);
+	for (i = 0; i < num_devices; i++) {
+		if (hi_res_scroll_devices[i].product_id == product_id)
+			return hi_res_scroll_devices[i].microns_per_hi_res_unit;
+	}
+	/* We don't have a value for this device, so use a sensible default. */
+	return 406;
+}
+
+static int hi_res_scroll_enable(struct hidpp_device *hidpp)
+{
+	int ret;
+	u8 multiplier;
+
+	if (hidpp->quirks & HIDPP_QUIRK_HI_RES_SCROLL_X2121) {
+		ret = hidpp_hrw_set_wheel_mode(hidpp, false, true, false);
+		hidpp_hrw_get_wheel_capability(hidpp, &multiplier);
+	} else if (hidpp->quirks & HIDPP_QUIRK_HI_RES_SCROLL_X2120) {
+		ret = hidpp_hrs_set_highres_scrolling_mode(hidpp, true,
+							   &multiplier);
+	} else /* if (hidpp->quirks & HIDPP_QUIRK_HI_RES_SCROLL_1P0) */ {
+		ret = hidpp10_enable_scrolling_acceleration(hidpp);
+		multiplier = 8;
+	}
+	if (ret)
+		return ret;
+
+	hidpp->vertical_wheel_counter.resolution_multiplier = multiplier;
+	hidpp->vertical_wheel_counter.microns_per_hi_res_unit =
+		hi_res_scroll_look_up_microns(hidpp->hid_dev->product);
+	hid_info(hidpp->hid_dev, "multiplier = %d, microns = %d\n",
+		 multiplier,
+		 hidpp->vertical_wheel_counter.microns_per_hi_res_unit);
+	return 0;
+}
+
 /* -------------------------------------------------------------------------- */
 /* Generic HID++ devices                                                      */
 /* -------------------------------------------------------------------------- */
@@ -2593,6 +2765,11 @@ 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);
+
+	if (hidpp->quirks & HIDPP_QUIRK_HI_RES_SCROLL) {
+		input_set_capability(input, EV_REL, REL_WHEEL_HI_RES);
+		hidpp->vertical_wheel_counter.dev = input;
+	}
 }
 
 static int hidpp_input_configured(struct hid_device *hdev,
@@ -2711,6 +2888,27 @@ static int hidpp_raw_event(struct hid_device *hdev, struct hid_report *report,
 	return 0;
 }
 
+static int hidpp_event(struct hid_device *hdev, struct hid_field *field,
+	struct hid_usage *usage, __s32 value)
+{
+	/* This function will only be called for scroll events, due to the
+	 * restriction imposed in hidpp_usages.
+	 */
+	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
+	struct hid_scroll_counter *counter = &hidpp->vertical_wheel_counter;
+	/* A scroll event may occur before the multiplier has been retrieved or
+	 * the input device set, or high-res scroll enabling may fail. In such
+	 * cases we must return early (falling back to default behaviour) to
+	 * avoid a crash in hid_scroll_counter_handle_scroll.
+	 */
+	if (!(hidpp->quirks & HIDPP_QUIRK_HI_RES_SCROLL) || value == 0
+	    || counter->dev == NULL || counter->resolution_multiplier == 0)
+		return 0;
+
+	hid_scroll_counter_handle_scroll(counter, value);
+	return 1;
+}
+
 static int hidpp_initialize_battery(struct hidpp_device *hidpp)
 {
 	static atomic_t battery_no = ATOMIC_INIT(0);
@@ -2922,6 +3120,9 @@ static void hidpp_connect_event(struct hidpp_device *hidpp)
 	if (hidpp->battery.ps)
 		power_supply_changed(hidpp->battery.ps);
 
+	if (hidpp->quirks & HIDPP_QUIRK_HI_RES_SCROLL)
+		hi_res_scroll_enable(hidpp);
+
 	if (!(hidpp->quirks & HIDPP_QUIRK_NO_HIDINPUT) || hidpp->delayed_input)
 		/* if the input nodes are already created, we can stop now */
 		return;
@@ -3107,6 +3308,10 @@ static void hidpp_remove(struct hid_device *hdev)
 	mutex_destroy(&hidpp->send_mutex);
 }
 
+#define LDJ_DEVICE(product) \
+	HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE, \
+		   USB_VENDOR_ID_LOGITECH, (product))
+
 static const struct hid_device_id hidpp_devices[] = {
 	{ /* wireless touchpad */
 	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
@@ -3121,10 +3326,39 @@ static const struct hid_device_id hidpp_devices[] = {
 	  HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_LOGITECH,
 		USB_DEVICE_ID_LOGITECH_T651),
 	  .driver_data = HIDPP_QUIRK_CLASS_WTP },
+	{ /* Mouse Logitech Anywhere MX */
+	  LDJ_DEVICE(0x1017), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_1P0 },
+	{ /* Mouse Logitech Cube */
+	  LDJ_DEVICE(0x4010), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2120 },
+	{ /* Mouse Logitech M335 */
+	  LDJ_DEVICE(0x4050), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ /* Mouse Logitech M515 */
+	  LDJ_DEVICE(0x4007), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2120 },
 	{ /* Mouse logitech M560 */
-	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
-		USB_VENDOR_ID_LOGITECH, 0x402d),
-	  .driver_data = HIDPP_QUIRK_DELAYED_INIT | HIDPP_QUIRK_CLASS_M560 },
+	  LDJ_DEVICE(0x402d),
+	  .driver_data = HIDPP_QUIRK_DELAYED_INIT | HIDPP_QUIRK_CLASS_M560
+		| HIDPP_QUIRK_HI_RES_SCROLL_X2120 },
+	{ /* Mouse Logitech M705 (firmware RQM17) */
+	  LDJ_DEVICE(0x101b), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_1P0 },
+	{ /* Mouse Logitech M705 (firmware RQM67) */
+	  LDJ_DEVICE(0x406d), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ /* Mouse Logitech M720 */
+	  LDJ_DEVICE(0x405e), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ /* Mouse Logitech MX Anywhere 2 */
+	  LDJ_DEVICE(0x404a), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ LDJ_DEVICE(0xb013), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ LDJ_DEVICE(0xb018), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ LDJ_DEVICE(0xb01f), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ /* Mouse Logitech MX Anywhere 2S */
+	  LDJ_DEVICE(0x406a), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ /* Mouse Logitech MX Master */
+	  LDJ_DEVICE(0x4041), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ LDJ_DEVICE(0x4060), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ LDJ_DEVICE(0x4071), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ /* Mouse Logitech MX Master 2S */
+	  LDJ_DEVICE(0x4069), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_X2121 },
+	{ /* Mouse Logitech Performance MX */
+	  LDJ_DEVICE(0x101a), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_1P0 },
 	{ /* Keyboard logitech K400 */
 	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
 		USB_VENDOR_ID_LOGITECH, 0x4024),
@@ -3144,12 +3378,19 @@ static const struct hid_device_id hidpp_devices[] = {
 
 MODULE_DEVICE_TABLE(hid, hidpp_devices);
 
+static const struct hid_usage_id hidpp_usages[] = {
+	{ HID_GD_WHEEL, EV_REL, REL_WHEEL },
+	{ HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1}
+};
+
 static struct hid_driver hidpp_driver = {
 	.name = "logitech-hidpp-device",
 	.id_table = hidpp_devices,
 	.probe = hidpp_probe,
 	.remove = hidpp_remove,
 	.raw_event = hidpp_raw_event,
+	.usage_table = hidpp_usages,
+	.event = hidpp_event,
 	.input_configured = hidpp_input_configured,
 	.input_mapping = hidpp_input_mapping,
 	.input_mapped = hidpp_input_mapped,
-- 
2.19.0.rc0.228.g281dcd1b4d0-goog

[PATCH v2 5/5] Use LDJ_DEVICE macro for existing Logitech mice

[Harry Cutts]

Signed-off-by: Harry Cutts <hcutts@chromium.org>
---

Changes in v2:
* Changed the REL_WHEEL_HI_RES code to use micrometres (a.k.a. microns)
  as its units, instead of 256ths of a millimetre.
* Removed support for mice connecting over Bluetooth, due to a bug where
  the mouse's high-res mode and the driver's settings get out of sync
  when the mouse is power cycled.
* Moved the creation of the HID++ 1.0 function and the refactor to use
  the LDJ_DEVICE macro into separate patches.
* Added a couple of explanatory comments to the Logitech driver.

 drivers/hid/hid-logitech-hidpp.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index fd6a8c325fa0..5f0c080059c6 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -3314,13 +3314,11 @@ static void hidpp_remove(struct hid_device *hdev)
 
 static const struct hid_device_id hidpp_devices[] = {
 	{ /* wireless touchpad */
-	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
-		USB_VENDOR_ID_LOGITECH, 0x4011),
+	  LDJ_DEVICE(0x4011),
 	  .driver_data = HIDPP_QUIRK_CLASS_WTP | HIDPP_QUIRK_DELAYED_INIT |
 			 HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS },
 	{ /* wireless touchpad T650 */
-	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
-		USB_VENDOR_ID_LOGITECH, 0x4101),
+	  LDJ_DEVICE(0x4101),
 	  .driver_data = HIDPP_QUIRK_CLASS_WTP | HIDPP_QUIRK_DELAYED_INIT },
 	{ /* wireless touchpad T651 */
 	  HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_LOGITECH,
@@ -3360,16 +3358,13 @@ static const struct hid_device_id hidpp_devices[] = {
 	{ /* Mouse Logitech Performance MX */
 	  LDJ_DEVICE(0x101a), .driver_data = HIDPP_QUIRK_HI_RES_SCROLL_1P0 },
 	{ /* Keyboard logitech K400 */
-	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
-		USB_VENDOR_ID_LOGITECH, 0x4024),
+	  LDJ_DEVICE(0x4024),
 	  .driver_data = HIDPP_QUIRK_CLASS_K400 },
 	{ /* Solar Keyboard Logitech K750 */
-	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
-		USB_VENDOR_ID_LOGITECH, 0x4002),
+	  LDJ_DEVICE(0x4002),
 	  .driver_data = HIDPP_QUIRK_CLASS_K750 },
 
-	{ HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
-		USB_VENDOR_ID_LOGITECH, HID_ANY_ID)},
+	{ LDJ_DEVICE(HID_ANY_ID) },
 
 	{ HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_LOGITECH_G920_WHEEL),
 		.driver_data = HIDPP_QUIRK_CLASS_G920 | HIDPP_QUIRK_FORCE_OUTPUT_REPORTS},
-- 
2.19.0.rc0.228.g281dcd1b4d0-goog

Re: [PATCH v2 0/5] Add support for high-resolution scrolling on Logitech mice

[Benjamin Tissoires]

Hi Harry,

On Thu, Aug 30, 2018 at 11:56 PM Harry Cutts <hcutts@chromium.org> wrote:
>
> Hi everyone,
>
> This is v2 of the patch set adding support for high-resolution scroll
> wheels on Logitech mice. See the linux-input "Reporting high-resolution
> scroll events" thread [0] for previous discussion of the evdev changes.
> I would love to hear your feedback.

Series looks good. I just tested it on a regular Logitech mouse and a
MX Master with high-res scrolling and everything works as expected.

Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Cheers,
Benjamin

>
> Thanks,
>
> Harry Cutts
> Chrome OS Touch/Input team
>
> [0]: https://www.spinics.net/lists/linux-input/msg57380.html
>
>
> Changes in v2:
> * Changed the REL_WHEEL_HI_RES code to use micrometres (a.k.a. microns)
>   as its units, instead of 256ths of a millimetre.
> * Removed support for mice connecting over Bluetooth, due to a bug where
>   the mouse's high-res mode and the driver's settings get out of sync
>   when the mouse is power cycled.
> * Moved the creation of the HID++ 1.0 function and the refactor to use
>   the LDJ_DEVICE macro into separate patches.
> * Added a couple of explanatory comments to the Logitech driver.
>
> Harry Cutts (5):
>   Add the `REL_WHEEL_HI_RES` event code
>   Create a utility class for counting scroll events
>   Add function to enable HID++ 1.0 "scrolling acceleration"
>   Enable high-resolution scrolling on Logitech mice
>   Use LDJ_DEVICE macro for existing Logitech mice
>
>  Documentation/input/event-codes.rst    |  11 +-
>  drivers/hid/hid-input.c                |  45 ++++
>  drivers/hid/hid-logitech-hidpp.c       | 311 ++++++++++++++++++++++---
>  include/linux/hid.h                    |  28 +++
>  include/uapi/linux/input-event-codes.h |   1 +
>  5 files changed, 368 insertions(+), 28 deletions(-)
>
> --
> 2.19.0.rc0.228.g281dcd1b4d0-goog
>

Re: [PATCH v2 0/5] Add support for high-resolution scrolling on Logitech mice

[Jiri Kosina]

On Thu, 30 Aug 2018, Harry Cutts wrote:

> This is v2 of the patch set adding support for high-resolution scroll 
> wheels on Logitech mice. See the linux-input "Reporting high-resolution 
> scroll events" thread [0] for previous discussion of the evdev changes. 
> I would love to hear your feedback.

Queued in for-4.20/logitech-highres. Thanks,

-- 
Jiri Kosina
SUSE Labs