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[v3,08/17] HID: input: calculate resolution for pressure

Message ID 20220513093927.1632262-9-acz@semihalf.com
State Superseded
Headers show
Series *** Implement simple haptic HID support *** | expand

Commit Message

Angela Czubak May 13, 2022, 9:39 a.m. UTC 
Assume that if the pressure is given in newtons it should be normalized
to grams. If the pressure has no unit do not calculate resolution.

Signed-off-by: Angela Czubak <acz@semihalf.com>
---
 drivers/hid/hid-input.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)
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Patch

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 77f2930f78f5..c9f8405c0522 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -303,6 +303,19 @@  __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code)
 		}
 		break;
 
+	case ABS_PRESSURE:
+	case ABS_MT_PRESSURE:
+		if (field->unit == HID_UNIT_NEWTON) {
+			/* Convert to grams, 1 newton is 101.97 grams */
+			prev = physical_extents;
+			physical_extents *= 10197;
+			if (physical_extents < prev)
+				return 0;
+			unit_exponent -= 2;
+		} else if (field->unit != HID_UNIT_GRAM) {
+			return 0;
+		}
+		break;
 	default:
 		return 0;
 	}