[PATCH 3.10 132/173] HID:hid-lg4ff: Scale autocentering force properly on Logitech wheel

Greg Kroah-Hartman
2013-12-02T19:11:55Z

From: Simon Wood <simon@mungewell.org>

commit f8c231569a7a455dfa1907294a46ba52b3aa8859 upstream.

Adjust the scaling and lineartity to match that of the Windows
driver (from MOMO testing).

Reported-by: Elias Vanderstuyft <elias.vds@gmail.com>
Signed-off-by: Simon Wood <simon@mungewell.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/hid/hid-lg4ff.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

--- a/drivers/hid/hid-lg4ff.c
+++ b/drivers/hid/hid-lg4ff.c
@@ -218,12 +218,21 @@ static void hid_lg4ff_set_autocenter_def
struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
__s32 *value = report->field[0]->value;
+ __u32 expand_a, expand_b;
+
+ if (magnitude <= 0xaaaa) {
+ expand_a = 0x0c * magnitude;
+ expand_b = 0x80 * magnitude;
+ } else {
+ expand_a = (0x0c * 0xaaaa) + 0x06 * (magnitude - 0xaaaa);
+ expand_b = (0x80 * 0xaaaa) + 0xff * (magnitude - 0xaaaa);
+ }

value[0] = 0xfe;
value[1] = 0x0d;
- value[2] = magnitude >> 13;
- value[3] = magnitude >> 13;
- value[4] = magnitude >> 8;
+ value[2] = expand_a / 0xaaaa;
+ value[3] = expand_a / 0xaaaa;
+ value[4] = expand_b / 0xaaaa;
value[5] = 0x00;
value[6] = 0x00;