From 825911492eb15bf8bb7fb94bc0c0421fe7a6327d Mon Sep 17 00:00:00 2001
From: Sing-Han Chen <singhanc@nvidia.com>
Date: Wed, 12 Jan 2022 17:41:43 +0800
Subject: [PATCH] ucsi_ccg: Check DEV_INT bit only when starting CCG4
Git-commit: 825911492eb15bf8bb7fb94bc0c0421fe7a6327d
References: git-fixes
Patch-mainline: v5.17-rc2

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: 247c554a14aa ("usb: typec: ucsi: add support for Cypress CCGx")
Cc: stable@vger.kernel.org
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Sing-Han Chen <singhanc@nvidia.com>
Signed-off-by: Wayne Chang <waynec@nvidia.com>
Link: https://lore.kernel.org/r/20220112094143.628610-1-waynec@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/typec/ucsi/ucsi_ccg.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/usb/typec/ucsi/ucsi_ccg.c
+++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
@@ -17,6 +17,8 @@
 #include <asm/unaligned.h>
 #include "ucsi.h"
 
+#define  DEV_INT				BIT(0)
+
 struct ucsi_ccg {
 	struct device *dev;
 	struct ucsi *ucsi;
@@ -130,7 +132,7 @@ static int ucsi_ccg_init(struct ucsi_ccg
 		if (status < 0)
 			return status;
 
-		if (!data)
+		if (!(data & DEV_INT))
 			return 0;
 
 		status = ccg_write(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));