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HID: dockchannel-hid: settle 50 ms after releasing the AFE reset #1083

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Merged
RyanTheTide merged 1 commit into from
Nov 8, 2026
Merged

HID: dockchannel-hid: settle 50 ms after releasing the AFE reset #1083

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24 changes: 18 additions & 6 deletions drivers/hid/dockchannel-hid/dockchannel-hid.c
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Original file line number Diff line number Diff line change
Expand Up @@ -535,7 +535,8 @@ static int dchid_register_ring(struct dockchannel_hid *dchid)
/*
* Power method 2: announce the transition, drive the AFE reset line to the
* new state and confirm the transition. The reset is asserted for a power-off
* and held for 50 ms, and released for a power-on.
* and held for 50 ms, and released for a power-on and given 50 ms to settle
* before the transition is confirmed.
*/
static int dchid_pm2_set_power(struct dchid_iface *iface, u8 state)
{
Expand All @@ -553,12 +554,23 @@ static int dchid_pm2_set_power(struct dchid_iface *iface, u8 state)
if (state == DCHID_POWER_STATE_ON)
fsleep(50 * USEC_PER_MSEC);
} else {
ret = gpiod_set_value_cansleep(dchid->afe_reset,
state == DCHID_POWER_STATE_OFF);
if (ret < 0)
bool off = state == DCHID_POWER_STATE_OFF;

ret = gpiod_set_value_cansleep(dchid->afe_reset, off);
if (ret < 0) {
dev_err(dchid->dev, "%s: failed to %s the AFE reset: %d\n",
iface->name, off ? "assert" : "release", ret);
return ret;
if (state == DCHID_POWER_STATE_OFF)
fsleep(50 * USEC_PER_MSEC);
}
dev_dbg(dchid->dev, "%s: AFE reset %s\n", iface->name,
off ? "asserted" : "released");
/*
* The sequence validated on J716s (M5 Pro, MTP firmware
* 6320.86.1, "Touch MT ready" on 3 of 3 boots) also waits
* 50 ms after the release before HasChanged, as the
* firmware-managed path above does.
*/
fsleep(50 * USEC_PER_MSEC);
}

dchid_pm2_command(iface->index, state, true, msg);
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