mt_set_mode() accepts 2 boolean switches indicating whether the device
(if it follows Windows Precision Touchpad specification) should report
hardware buttons and/or surface contacts. For a casual reader it is
completely not clear, as they look at the call site, which exact mode
is being requested.

Define report_mode enum and change mt_set_mode() to accept is as
an argument instead. This allows to write:

	mt_set_modes(hdev, HID_LATENCY_NORMAL, TOUCHPAD_REPORT_ALL);

or

	mt_set_modes(hdev, HID_LATENCY_HIGH, TOUCHPAD_REPORT_BUTTONS);

which makes intent much more clear.

Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---

v2: addressed Benjamin's comments, added his reviewed-by.

 drivers/hid/hid-multitouch.c | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 99812c0f830b..53fb92453e88 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -31,6 +31,7 @@
  * [1] https://gitlab.freedesktop.org/libevdev/hid-tools
  */
 
+#include <linux/bits.h>
 #include <linux/device.h>
 #include <linux/hid.h>
 #include <linux/module.h>
@@ -83,6 +84,13 @@ enum latency_mode {
 	HID_LATENCY_HIGH = 1,
 };
 
+enum report_mode {
+	TOUCHPAD_REPORT_NONE = 0,
+	TOUCHPAD_REPORT_BUTTONS = BIT(0),
+	TOUCHPAD_REPORT_CONTACTS = BIT(1),
+	TOUCHPAD_REPORT_ALL = TOUCHPAD_REPORT_BUTTONS | TOUCHPAD_REPORT_CONTACTS,
+};
+
 #define MT_IO_FLAGS_RUNNING		0
 #define MT_IO_FLAGS_ACTIVE_SLOTS	1
 #define MT_IO_FLAGS_PENDING_SLOTS	2
@@ -1486,8 +1494,7 @@ static bool mt_need_to_apply_feature(struct hid_device *hdev,
 				     struct hid_field *field,
 				     struct hid_usage *usage,
 				     enum latency_mode latency,
-				     bool surface_switch,
-				     bool button_switch,
+				     enum report_mode report_mode,
 				     bool *inputmode_found)
 {
 	struct mt_device *td = hid_get_drvdata(hdev);
@@ -1542,11 +1549,11 @@ static bool mt_need_to_apply_feature(struct hid_device *hdev,
 		return true;
 
 	case HID_DG_SURFACESWITCH:
-		field->value[index] = surface_switch;
+		field->value[index] = !!(report_mode & TOUCHPAD_REPORT_CONTACTS);
 		return true;
 
 	case HID_DG_BUTTONSWITCH:
-		field->value[index] = button_switch;
+		field->value[index] = !!(report_mode & TOUCHPAD_REPORT_BUTTONS);
 		return true;
 	}
 
@@ -1554,7 +1561,7 @@ static bool mt_need_to_apply_feature(struct hid_device *hdev,
 }
 
 static void mt_set_modes(struct hid_device *hdev, enum latency_mode latency,
-			 bool surface_switch, bool button_switch)
+			 enum report_mode report_mode)
 {
 	struct hid_report_enum *rep_enum;
 	struct hid_report *rep;
@@ -1579,8 +1586,7 @@ static void mt_set_modes(struct hid_device *hdev, enum latency_mode latency,
 							     rep->field[i],
 							     usage,
 							     latency,
-							     surface_switch,
-							     button_switch,
+							     report_mode,
 							     &inputmode_found))
 					update_report = true;
 			}
@@ -1820,7 +1826,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 		dev_warn(&hdev->dev, "Cannot allocate sysfs group for %s\n",
 				hdev->name);
 
-	mt_set_modes(hdev, HID_LATENCY_NORMAL, true, true);
+	mt_set_modes(hdev, HID_LATENCY_NORMAL, TOUCHPAD_REPORT_ALL);
 
 	return 0;
 }
@@ -1832,9 +1838,9 @@ static int mt_suspend(struct hid_device *hdev, pm_message_t state)
 	/* High latency is desirable for power savings during S3/S0ix */
 	if ((td->mtclass.quirks & MT_QUIRK_DISABLE_WAKEUP) ||
 	    !hid_hw_may_wakeup(hdev))
-		mt_set_modes(hdev, HID_LATENCY_HIGH, false, false);
+		mt_set_modes(hdev, HID_LATENCY_HIGH, TOUCHPAD_REPORT_NONE);
 	else
-		mt_set_modes(hdev, HID_LATENCY_HIGH, true, true);
+		mt_set_modes(hdev, HID_LATENCY_HIGH, TOUCHPAD_REPORT_ALL);
 
 	return 0;
 }
@@ -1842,7 +1848,7 @@ static int mt_suspend(struct hid_device *hdev, pm_message_t state)
 static int mt_reset_resume(struct hid_device *hdev)
 {
 	mt_release_contacts(hdev);
-	mt_set_modes(hdev, HID_LATENCY_NORMAL, true, true);
+	mt_set_modes(hdev, HID_LATENCY_NORMAL, TOUCHPAD_REPORT_ALL);
 	return 0;
 }
 
@@ -1854,7 +1860,7 @@ static int mt_resume(struct hid_device *hdev)
 
 	hid_hw_idle(hdev, 0, 0, HID_REQ_SET_IDLE);
 
-	mt_set_modes(hdev, HID_LATENCY_NORMAL, true, true);
+	mt_set_modes(hdev, HID_LATENCY_NORMAL, TOUCHPAD_REPORT_ALL);
 
 	return 0;
 }
-- 
2.47.0.163.g1226f6d8fa-goog


-- 
Dmitry

On Mon, 28 Oct 2024 12:07:50 -0700, Dmitry Torokhov wrote:
> mt_set_mode() accepts 2 boolean switches indicating whether the device
> (if it follows Windows Precision Touchpad specification) should report
> hardware buttons and/or surface contacts. For a casual reader it is
> completely not clear, as they look at the call site, which exact mode
> is being requested.
> 
> Define report_mode enum and change mt_set_mode() to accept is as
> an argument instead. This allows to write:
> 
> [...]

Applied to hid/hid.git (for-6.13/multitouch), thanks!

[1/1] HID: multitouch: make mt_set_mode() less cryptic
      https://git.kernel.org/hid/hid/c/5f21e2242f9f

Cheers,
-- 
Benjamin Tissoires <bentiss@kernel.org>