[PATCH v3 2/3] HID: multitouch: add control of the feature "Maximum Contact Number"

From: benjamin.tissoires
Date: Sat Feb 04 2012 - 11:09:08 EST


From: Benjamin Tissoires <benjamin.tissoires@xxxxxxx>

Some devices, like Perixx Peripad 701 do not work if the feature
"Maximum Contact Number" is not set to the right value.
This patch allows hid-multitouch to control this feature.

If the programmer fills the field maxcontacts in the mt_class,
then the driver will set the feature to this value. It is safe
for current drivers as the feature is read/write in the HID norm
and all devices should implement the norm.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxx>
---
drivers/hid/hid-multitouch.c | 32 ++++++++++++++++++++++++++++++++
1 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 4c69749..825759e 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -77,6 +77,8 @@ struct mt_device {
unsigned last_slot_field; /* the last field of a slot */
int last_mt_collection; /* last known mt-related collection */
__s8 inputmode; /* InputMode HID feature, -1 if non-existent */
+ __s8 maxcontact_report_id; /* Maximum Contact Number HID feature,
+ -1 if non-existent */
__u8 num_received; /* how many contacts we received */
__u8 num_expected; /* expected last contact index */
__u8 maxcontacts;
@@ -242,6 +244,7 @@ static void mt_feature_mapping(struct hid_device *hdev,
td->inputmode = field->report->id;
break;
case HID_DG_CONTACTMAX:
+ td->maxcontact_report_id = field->report->id;
td->maxcontacts = field->value[0];
if (td->mtclass.maxcontacts)
/* check if the maxcontacts is given by the class */
@@ -606,6 +609,32 @@ static void mt_set_input_mode(struct hid_device *hdev)
}
}

+static void mt_set_maxcontacts(struct hid_device *hdev)
+{
+ struct mt_device *td = hid_get_drvdata(hdev);
+ struct hid_report *r;
+ struct hid_report_enum *re;
+ int fieldmax, max;
+
+ if (td->maxcontact_report_id < 0)
+ return;
+
+ if (!td->mtclass.maxcontacts)
+ return;
+
+ re = &hdev->report_enum[HID_FEATURE_REPORT];
+ r = re->report_id_hash[td->maxcontact_report_id];
+ if (r) {
+ max = td->mtclass.maxcontacts;
+ fieldmax = r->field[0]->logical_maximum;
+ max = min(fieldmax, max);
+ if (r->field[0]->value[0] != max) {
+ r->field[0]->value[0] = max;
+ usbhid_submit_report(hdev, r, USB_DIR_OUT);
+ }
+ }
+}
+
static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
int ret, i;
@@ -631,6 +660,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
}
td->mtclass = *mtclass;
td->inputmode = -1;
+ td->maxcontact_report_id = -1;
td->last_mt_collection = -1;
hid_set_drvdata(hdev, td);

@@ -653,6 +683,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)

ret = sysfs_create_group(&hdev->dev.kobj, &mt_attribute_group);

+ mt_set_maxcontacts(hdev);
mt_set_input_mode(hdev);

return 0;
@@ -665,6 +696,7 @@ fail:
#ifdef CONFIG_PM
static int mt_reset_resume(struct hid_device *hdev)
{
+ mt_set_maxcontacts(hdev);
mt_set_input_mode(hdev);
return 0;
}
--
1.7.7.6

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