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SubjectRe: [PATCH v2] Input: elantech: Enable SMBus on new (2018+) systems
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at 16:33, Benjamin Tissoires <benjamin.tissoires@redhat.com> wrote:

> On Mon, Jan 21, 2019 at 8:03 AM Kai-Heng Feng
> <kai.heng.feng@canonical.com> wrote:
>> There are some new HP laptops with Elantech touchpad don't support
>> multitouch.
>>
>> Currently we use ETP_NEW_IC_SMBUS_HOST_NOTIFY() to check if SMBus is
>> supported, but in addition to firmware version, the bus type also
>> informs us if the IC can support SMBus, so also check that.
>>
>> In case of breaking old ICs, only enables SMBus on systems manufactured
>> after 2018, alongsides aforementioned checks.
>>
>> Lastly, consolidats all check into elantech_use_host_notify() and use it
>> to determine whether to use PS/2 or SMBus.
>>
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>> ---
>> v2:
>> - Wording.
>> - Further restrain on older systems (< 2018).
>>
>> drivers/input/mouse/elantech.c | 63 ++++++++++++++++++----------------
>> 1 file changed, 34 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/input/mouse/elantech.c
>> b/drivers/input/mouse/elantech.c
>> index 9fe075c137dc..2594130b0079 100644
>> --- a/drivers/input/mouse/elantech.c
>> +++ b/drivers/input/mouse/elantech.c
>> @@ -1799,6 +1799,39 @@ static int elantech_create_smbus(struct psmouse
>> *psmouse,
>> leave_breadcrumbs);
>> }
>>
>> +static bool elantech_use_host_notify(struct psmouse *psmouse,
>> + struct elantech_device_info *info)
>> +{
>> + bool host_notify = false;
>> +
>> + if (ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version))
>> + host_notify = true;
>> + else {
>> + switch (info->bus) {
>> + case ETP_BUS_PS2_ONLY:
>> + /* expected case */
>> + break;
>> + case ETP_BUS_SMB_ALERT_ONLY:
>> + /* fall-through */
>> + case ETP_BUS_PS2_SMB_ALERT:
>> + psmouse_dbg(psmouse, "Ignoring SMBus provider
>> through alert protocol.\n");
>> + break;
>> + case ETP_BUS_SMB_HST_NTFY_ONLY:
>> + /* fall-through */
>> + case ETP_BUS_PS2_SMB_HST_NTFY:
>> + host_notify = true;
>> + break;
>> + default:
>> + psmouse_dbg(psmouse,
>> + "Ignoring SMBus bus provider %d.\n",
>> + info->bus);
>> + }
>> + }
>> +
>> + /* SMbus implementation is stable after 2018 */
>> + return host_notify && (dmi_get_bios_year() >= 2018);
>
> Strictly speaking, the check for the year should be in the `switch
> (info->bus)`, but OTOH, laptops with ETP_NEW_IC_SMBUS_HOST_NOTIFY
> should be manufactured after 2018 too, so we should be good.
>
> Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Hi Dmitry,

Would it be possible to include this patch?

Kai-Heng

>
> Cheers,
> Benjamin
>
>> +}
>> +
>> /**
>> * elantech_setup_smbus - called once the PS/2 devices are enumerated
>> * and decides to instantiate a SMBus InterTouch device.
>> @@ -1818,7 +1851,7 @@ static int elantech_setup_smbus(struct psmouse
>> *psmouse,
>> * i2c_blacklist_pnp_ids.
>> * Old ICs are up to the user to decide.
>> */
>> - if (!ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version) ||
>> + if (!elantech_use_host_notify(psmouse, info) ||
>> psmouse_matches_pnp_id(psmouse, i2c_blacklist_pnp_ids))
>> return -ENXIO;
>> }
>> @@ -1838,34 +1871,6 @@ static int elantech_setup_smbus(struct psmouse
>> *psmouse,
>> return 0;
>> }
>>
>> -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 */
>> - break;
>> - case ETP_BUS_SMB_ALERT_ONLY:
>> - /* fall-through */
>> - case ETP_BUS_PS2_SMB_ALERT:
>> - psmouse_dbg(psmouse, "Ignoring SMBus provider through
>> alert protocol.\n");
>> - break;
>> - case ETP_BUS_SMB_HST_NTFY_ONLY:
>> - /* fall-through */
>> - case ETP_BUS_PS2_SMB_HST_NTFY:
>> - return true;
>> - default:
>> - psmouse_dbg(psmouse,
>> - "Ignoring SMBus bus provider %d.\n",
>> - info->bus);
>> - }
>> -
>> - return false;
>> -}
>> -
>> int elantech_init_smbus(struct psmouse *psmouse)
>> {
>> struct elantech_device_info info;
>> —

>> 2.17.1

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