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Input: elantech - detect new ICs and setup Host Notify for them

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New ICs are using a different scheme for the alternate bus parameter.
Given that they are new and are only using either PS2 only or PS2 + SMBus
Host Notify, we force those new ICs to use the SMBus solution for enhanced
reporting.

This allows the touchpad found on the Lenovo T480s to report 5 fingers
every 8 ms, instead of having a limit of 2 every 8 ms.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: KT Liao <kt.liao@emc.com.tw>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Benjamin Tissoires 2018-05-22 17:30:07 -07:00 committed by Dmitry Torokhov
parent 21c48dbde0
commit df077237cf
2 changed files with 22 additions and 4 deletions
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11
drivers/input/mouse/elantech.c
View file

@ -1793,11 +1793,11 @@ static int elantech_setup_smbus(struct psmouse *psmouse,
if (elantech_smbus == ELANTECH_SMBUS_NOT_SET) {
/*
* FIXME:
* constraint the I2C capable devices by using FW version,
* board version, or by using DMI matching
* New ICs are enabled by default.
* Old ICs are up to the user to decide.
*/
return -ENXIO;
if (!ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version))
return -ENXIO;
}
psmouse_info(psmouse, "Trying to set up SMBus access\n");
@ -1818,6 +1818,9 @@ static int elantech_setup_smbus(struct psmouse *psmouse,
static bool elantech_use_host_notify(struct psmouse *psmouse,
struct elantech_device_info *info)
{
if (ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version))
return true;
switch (info->bus) {
case ETP_BUS_PS2_ONLY:
/* expected case */

15
drivers/input/mouse/elantech.h
View file

@ -115,6 +115,21 @@
#define ETP_BUS_PS2_SMB_ALERT 3
#define ETP_BUS_PS2_SMB_HST_NTFY 4
/*
* New ICs are either using SMBus Host Notify or just plain PS2.
*
* ETP_FW_VERSION_QUERY is:
* Byte 1:
* - bit 0..3: IC BODY
* Byte 2:
* - bit 4: HiddenButton
* - bit 5: PS2_SMBUS_NOTIFY
* - bit 6: PS2CRCCheck
*/
#define ETP_NEW_IC_SMBUS_HOST_NOTIFY(fw_version) \
((((fw_version) & 0x0f2000) == 0x0f2000) && \
((fw_version) & 0x0000ff) > 0)
/*
* The base position for one finger, v4 hardware
*/