| Message ID | 1351241067-9521-3-git-send-email-benjamin.tissoires@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Jiri Kosina |
| Headers | show |
Hi Benjamin, > HID spec details special values for the HID field unit exponent. > Basically, the range [0x8..0xf] correspond to [-8..-1]. > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com> > --- Standard two's complement, in other words? > drivers/hid/hid-core.c | 10 +++++++++- > drivers/hid/hid-input.c | 19 +++++++++++++------ > 2 files changed, 22 insertions(+), 7 deletions(-) > > diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c > index 9904776..6bde6e4 100644 > --- a/drivers/hid/hid-core.c > +++ b/drivers/hid/hid-core.c > @@ -315,6 +315,7 @@ static s32 item_sdata(struct hid_item *item) > > static int hid_parser_global(struct hid_parser *parser, struct hid_item *item) > { > + __u32 raw_value; > switch (item->tag) { > case HID_GLOBAL_ITEM_TAG_PUSH: > > @@ -365,7 +366,14 @@ static int hid_parser_global(struct hid_parser *parser, struct hid_item *item) > return 0; > > case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT: > - parser->global.unit_exponent = item_sdata(item); > + /* Units exponent negative numbers are given through a special > + * table. > + * See "6.2.2.7 Global Items" for more information. */ > + raw_value = item_udata(item); > + if ((raw_value >> 3) == 1) > + parser->global.unit_exponent = raw_value - 16; > + else > + parser->global.unit_exponent = raw_value; I beleive the function you want is snto32(value, 4). > return 0; > > case HID_GLOBAL_ITEM_TAG_UNIT: > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c > index 1b0adc3..fc9f2b5 100644 > --- a/drivers/hid/hid-input.c > +++ b/drivers/hid/hid-input.c > @@ -215,7 +215,7 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code) > field->logical_minimum; > __s32 physical_extents = field->physical_maximum - > field->physical_minimum; > - __s32 prev; > + __s32 prev, tmp_exponent; > > /* Check if the extents are sane */ > if (logical_extents <= 0 || physical_extents <= 0) > @@ -235,17 +235,24 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code) > case ABS_MT_TOOL_Y: > case ABS_MT_TOUCH_MAJOR: > case ABS_MT_TOUCH_MINOR: > - if (field->unit == 0x11) { /* If centimeters */ > + if (field->unit & 0xffffff00) /* Not a length */ > + return 0; > + tmp_exponent = field->unit >> 4; > + if ((tmp_exponent >> 3) == 1) > + tmp_exponent -= 16; Ditto. > + switch (field->unit & 0xf) { > + case 0x1: /* If centimeters */ > /* Convert to millimeters */ > - unit_exponent += 1; > - } else if (field->unit == 0x13) { /* If inches */ > + unit_exponent += tmp_exponent; > + break; > + case 0x3: /* If inches */ > /* Convert to millimeters */ > prev = physical_extents; > physical_extents *= 254; > if (physical_extents < prev) > return 0; > - unit_exponent -= 1; > - } else { > + unit_exponent += tmp_exponent - 2; > + default: > return 0; > } > break; > -- > 1.7.11.7 > Thanks, Henrik -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Henrik, On Mon, Oct 29, 2012 at 8:05 PM, Henrik Rydberg <rydberg@euromail.se> wrote: > Hi Benjamin, > >> HID spec details special values for the HID field unit exponent. >> Basically, the range [0x8..0xf] correspond to [-8..-1]. >> >> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com> >> --- > > Standard two's complement, in other words? yes, but for 4-bits values. The thing is that I didn't managed to figure out if it was allowed to give unit exponent with more than 4 bits... > >> drivers/hid/hid-core.c | 10 +++++++++- >> drivers/hid/hid-input.c | 19 +++++++++++++------ >> 2 files changed, 22 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c >> index 9904776..6bde6e4 100644 >> --- a/drivers/hid/hid-core.c >> +++ b/drivers/hid/hid-core.c >> @@ -315,6 +315,7 @@ static s32 item_sdata(struct hid_item *item) >> >> static int hid_parser_global(struct hid_parser *parser, struct hid_item *item) >> { >> + __u32 raw_value; >> switch (item->tag) { >> case HID_GLOBAL_ITEM_TAG_PUSH: >> >> @@ -365,7 +366,14 @@ static int hid_parser_global(struct hid_parser *parser, struct hid_item *item) >> return 0; >> >> case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT: >> - parser->global.unit_exponent = item_sdata(item); >> + /* Units exponent negative numbers are given through a special >> + * table. >> + * See "6.2.2.7 Global Items" for more information. */ >> + raw_value = item_udata(item); >> + if ((raw_value >> 3) == 1) >> + parser->global.unit_exponent = raw_value - 16; >> + else >> + parser->global.unit_exponent = raw_value; > > I beleive the function you want is snto32(value, 4). but to be sure, we should still do a test against (raw_value & 0xf0) for values with more than 4 bits, no? Cheers, Benjamin > >> return 0; >> >> case HID_GLOBAL_ITEM_TAG_UNIT: >> diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c >> index 1b0adc3..fc9f2b5 100644 >> --- a/drivers/hid/hid-input.c >> +++ b/drivers/hid/hid-input.c >> @@ -215,7 +215,7 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code) >> field->logical_minimum; >> __s32 physical_extents = field->physical_maximum - >> field->physical_minimum; >> - __s32 prev; >> + __s32 prev, tmp_exponent; >> >> /* Check if the extents are sane */ >> if (logical_extents <= 0 || physical_extents <= 0) >> @@ -235,17 +235,24 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code) >> case ABS_MT_TOOL_Y: >> case ABS_MT_TOUCH_MAJOR: >> case ABS_MT_TOUCH_MINOR: >> - if (field->unit == 0x11) { /* If centimeters */ >> + if (field->unit & 0xffffff00) /* Not a length */ >> + return 0; >> + tmp_exponent = field->unit >> 4; >> + if ((tmp_exponent >> 3) == 1) >> + tmp_exponent -= 16; > > Ditto. > >> + switch (field->unit & 0xf) { >> + case 0x1: /* If centimeters */ >> /* Convert to millimeters */ >> - unit_exponent += 1; >> - } else if (field->unit == 0x13) { /* If inches */ >> + unit_exponent += tmp_exponent; >> + break; >> + case 0x3: /* If inches */ >> /* Convert to millimeters */ >> prev = physical_extents; >> physical_extents *= 254; >> if (physical_extents < prev) >> return 0; >> - unit_exponent -= 1; >> - } else { >> + unit_exponent += tmp_exponent - 2; >> + default: >> return 0; >> } >> break; >> -- >> 1.7.11.7 >> > > Thanks, > Henrik -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 9904776..6bde6e4 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -315,6 +315,7 @@ static s32 item_sdata(struct hid_item *item) static int hid_parser_global(struct hid_parser *parser, struct hid_item *item) { + __u32 raw_value; switch (item->tag) { case HID_GLOBAL_ITEM_TAG_PUSH: @@ -365,7 +366,14 @@ static int hid_parser_global(struct hid_parser *parser, struct hid_item *item) return 0; case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT: - parser->global.unit_exponent = item_sdata(item); + /* Units exponent negative numbers are given through a special + * table. + * See "6.2.2.7 Global Items" for more information. */ + raw_value = item_udata(item); + if ((raw_value >> 3) == 1) + parser->global.unit_exponent = raw_value - 16; + else + parser->global.unit_exponent = raw_value; return 0; case HID_GLOBAL_ITEM_TAG_UNIT: diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index 1b0adc3..fc9f2b5 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -215,7 +215,7 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code) field->logical_minimum; __s32 physical_extents = field->physical_maximum - field->physical_minimum; - __s32 prev; + __s32 prev, tmp_exponent; /* Check if the extents are sane */ if (logical_extents <= 0 || physical_extents <= 0) @@ -235,17 +235,24 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code) case ABS_MT_TOOL_Y: case ABS_MT_TOUCH_MAJOR: case ABS_MT_TOUCH_MINOR: - if (field->unit == 0x11) { /* If centimeters */ + if (field->unit & 0xffffff00) /* Not a length */ + return 0; + tmp_exponent = field->unit >> 4; + if ((tmp_exponent >> 3) == 1) + tmp_exponent -= 16; + switch (field->unit & 0xf) { + case 0x1: /* If centimeters */ /* Convert to millimeters */ - unit_exponent += 1; - } else if (field->unit == 0x13) { /* If inches */ + unit_exponent += tmp_exponent; + break; + case 0x3: /* If inches */ /* Convert to millimeters */ prev = physical_extents; physical_extents *= 254; if (physical_extents < prev) return 0; - unit_exponent -= 1; - } else { + unit_exponent += tmp_exponent - 2; + default: return 0; } break;
HID spec details special values for the HID field unit exponent. Basically, the range [0x8..0xf] correspond to [-8..-1]. Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com> --- drivers/hid/hid-core.c | 10 +++++++++- drivers/hid/hid-input.c | 19 +++++++++++++------ 2 files changed, 22 insertions(+), 7 deletions(-)