[PATCH 05/15] Input - wacom: compute the HID report size to get the actual packet size

From: Benjamin Tissoires
Date: Mon Jun 30 2014 - 17:30:04 EST


This removes an USB dependency and is more accurate: the computed pktlen
is the actual maximum size of the reports forwarded by the device.

Given that the pktlen is correctly computed/validated, we can store it now
in the features struct instead of having a special handling in the rest of
the code.

Likewise, this information is not mandatory anymore in the description
of devices in wacom_wac.c. They will be removed in a separate patch.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
---
drivers/input/tablet/wacom_sys.c | 58 ++++++++++++++++++----------------------
1 file changed, 26 insertions(+), 32 deletions(-)

diff --git a/drivers/input/tablet/wacom_sys.c b/drivers/input/tablet/wacom_sys.c
index cd3d936..3f1cee6 100644
--- a/drivers/input/tablet/wacom_sys.c
+++ b/drivers/input/tablet/wacom_sys.c
@@ -149,7 +149,6 @@ static int wacom_parse_logical_collection(unsigned char *report,
if (features->type == BAMBOO_PT) {

/* Logical collection is only used by 3rd gen Bamboo Touch */
- features->pktlen = WACOM_PKGLEN_BBTOUCH3;
features->device_type = BTN_TOOL_FINGER;

features->x_max = features->y_max =
@@ -240,29 +239,6 @@ static int wacom_parse_hid(struct hid_device *hdev,
features->device_type = BTN_TOOL_FINGER;
/* touch device at least supports one touch point */
touch_max = 1;
- switch (features->type) {
- case TABLETPC2FG:
- features->pktlen = WACOM_PKGLEN_TPC2FG;
- break;
-
- case MTSCREEN:
- case WACOM_24HDT:
- features->pktlen = WACOM_PKGLEN_MTOUCH;
- break;
-
- case MTTPC:
- case MTTPC_B:
- features->pktlen = WACOM_PKGLEN_MTTPC;
- break;
-
- case BAMBOO_PT:
- features->pktlen = WACOM_PKGLEN_BBTOUCH;
- break;
-
- default:
- features->pktlen = WACOM_PKGLEN_GRAPHIRE;
- break;
- }

switch (features->type) {
case BAMBOO_PT:
@@ -305,8 +281,6 @@ static int wacom_parse_hid(struct hid_device *hdev,
}
} else if (pen) {
/* penabled only accepts exact bytes of data */
- if (features->type >= TABLETPC)
- features->pktlen = WACOM_PKGLEN_GRAPHIRE;
features->device_type = BTN_TOOL_PEN;
features->x_max =
get_unaligned_le16(&report[i + 3]);
@@ -1227,12 +1201,34 @@ static void wacom_calculate_res(struct wacom_features *features)
features->unitExpo);
}

+static int wacom_hid_report_len(struct hid_report *report)
+{
+ /* equivalent to DIV_ROUND_UP(report->size, 8) + !!(report->id > 0) */
+ return ((report->size - 1) >> 3) + 1 + (report->id > 0);
+}
+
+static size_t wacom_compute_pktlen(struct hid_device *hdev)
+{
+ struct hid_report_enum *report_enum;
+ struct hid_report *report;
+ size_t size = 0;
+
+ report_enum = hdev->report_enum + HID_INPUT_REPORT;
+
+ list_for_each_entry(report, &report_enum->report_list, list) {
+ size_t report_size = wacom_hid_report_len(report);
+ if (report_size > size)
+ size = report_size;
+ }
+
+ return size;
+}
+
static int wacom_probe(struct hid_device *hdev,
const struct hid_device_id *id)
{
struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
struct usb_device *dev = interface_to_usbdev(intf);
- struct usb_endpoint_descriptor *endpoint;
struct wacom *wacom;
struct wacom_wac *wacom_wac;
struct wacom_features *features;
@@ -1258,6 +1254,7 @@ static int wacom_probe(struct hid_device *hdev,
wacom_wac = &wacom->wacom_wac;
wacom_wac->features = *((struct wacom_features *)id->driver_data);
features = &wacom_wac->features;
+ features->pktlen = wacom_compute_pktlen(hdev);
if (features->pktlen > WACOM_PKGLEN_MAX) {
error = -EINVAL;
goto fail1;
@@ -1275,8 +1272,6 @@ static int wacom_probe(struct hid_device *hdev,
usb_make_path(dev, wacom->phys, sizeof(wacom->phys));
strlcat(wacom->phys, "/input0", sizeof(wacom->phys));

- endpoint = &intf->cur_altsetting->endpoint[0].desc;
-
/* set the default size in case we do not get them from hid */
wacom_set_default_phy(features);

@@ -1287,13 +1282,12 @@ static int wacom_probe(struct hid_device *hdev,

/*
* Intuos5 has no useful data about its touch interface in its
- * HID descriptor. If this is the touch interface (wMaxPacketSize
+ * HID descriptor. If this is the touch interface (PacketSize
* of WACOM_PKGLEN_BBTOUCH3), override the table values.
*/
if (features->type >= INTUOS5S && features->type <= INTUOSHT) {
- if (endpoint->wMaxPacketSize == WACOM_PKGLEN_BBTOUCH3) {
+ if (features->pktlen == WACOM_PKGLEN_BBTOUCH3) {
features->device_type = BTN_TOOL_FINGER;
- features->pktlen = WACOM_PKGLEN_BBTOUCH3;

features->x_max = 4096;
features->y_max = 4096;
--
2.0.0

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