Input: pm8941-pwrkey - simulate missed key press events

The status of the keys connected to the KPDPWR_N and RESIN_N pins
is identified by reading corresponding bits in the interrupt real
time status register.  If the status has changed by the time that
the interrupt is handled then a press event will be missed.

Maintain a last known status variable to find unbalanced release
events and simulate press events for each accordingly.

Signed-off-by: David Collins <collinsd@codeaurora.org>
Signed-off-by: Anjelique Melendez <quic_amelende@quicinc.com>
Link: https://lore.kernel.org/r/20220422191239.6271-6-quic_amelende@quicinc.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Author: David Collins

drivers/input/misc/pm8941-pwrkey.c

@@ -77,6 +77,7 @@ struct pm8941_pwrkey {
 	u32 code;
 	u32 sw_debounce_time_us;
 	ktime_t sw_debounce_end_time;
+	bool last_status;
 	const struct pm8941_data *data;
 };
 
@@ -167,6 +168,16 @@ static irqreturn_t pm8941_pwrkey_irq(int irq, void *_data)
 		pwrkey->sw_debounce_end_time = ktime_add_us(ktime_get(),
 						pwrkey->sw_debounce_time_us);
 
+	/*
+	 * Simulate a press event in case a release event occurred without a
+	 * corresponding press event.
+	 */
+	if (!pwrkey->last_status && !sts) {
+		input_report_key(pwrkey->input, pwrkey->code, 1);
+		input_sync(pwrkey->input);
+	}
+	pwrkey->last_status = sts;
+
 	input_report_key(pwrkey->input, pwrkey->code, sts);
 	input_sync(pwrkey->input);