usb: typec: tcpci: clear the fault status bit

According the "USB Type-C Port Controller Interface Specification v2.0"
the TCPC sets the fault status register bit-7
(AllRegistersResetToDefault) once the registers have been reset to
their default values.

This triggers an alert(-irq) on PTN5110 devices albeit we do mask the
fault-irq, which may cause a kernel hang. Fix this generically by writing
a one to the corresponding bit-7.

Cc: [e-mail]
Fixes: 74e656d6b055 ("staging: typec: Type-C Port Controller Interface driver (tcpci)")
Reported-by: "Angus Ainslie (Purism)" <[e-mail]>
Closes: https://lore.kernel.org/all/[e-mail]/
Reported-by: Christian Bach <[e-mail]>
Closes: https://lore.kernel.org/regressions/[e-mail]/t/
Signed-off-by: Marco Felsch <[e-mail]>
Signed-off-by: Fabio Estevam <[e-mail]>
Reviewed-by: Guenter Roeck <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/typec/tcpm/tcpci.c

···
 	if (time_after(jiffies, timeout))
 		return -ETIMEDOUT;
 
+	ret = tcpci_write16(tcpci, TCPC_FAULT_STATUS, TCPC_FAULT_STATUS_ALL_REG_RST_TO_DEFAULT);
+	if (ret < 0)
+		return ret;
+
 	/* Handle vendor init */
 	if (tcpci->data->init) {
 		ret = tcpci->data->init(tcpci, tcpci->data);

include/linux/usb/tcpci.h

···
 #define TCPC_POWER_STATUS_SINKING_VBUS	BIT(0)
 
 #define TCPC_FAULT_STATUS		0x1f
+#define TCPC_FAULT_STATUS_ALL_REG_RST_TO_DEFAULT BIT(7)
 
 #define TCPC_ALERT_EXTENDED		0x21