ucsi_ccg: Check DEV_INT bit only when starting CCG4

CCGx clears Bit 0:Device Interrupt in the INTR_REG
if CCGx is reset successfully. However, there might
be a chance that other bits in INTR_REG are not
cleared due to internal data queued in PPM. This case
misleads the driver that CCGx reset failed.

The commit checks bit 0 in INTR_REG and ignores other
bits. The ucsi driver would reset PPM later.

Fixes: 247c554 ("usb: typec: ucsi: add support for Cypress CCGx")
Cc: [email protected]
Reviewed-by: Heikki Krogerus <[email protected]>
Signed-off-by: Sing-Han Chen <[email protected]>
Signed-off-by: Wayne Chang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Sing-Han Chen

drivers/usb/typec/ucsi/ucsi_ccg.c

@@ -325,7 +325,7 @@ static int ucsi_ccg_init(struct ucsi_ccg *uc)
 		if (status < 0)
 			return status;
 
-		if (!data)
+		if (!(data & DEV_INT))
 			return 0;
 
 		status = ccg_write(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));