[PATCH 1/1] usb: pd: fix the SenderResponseTimer conform to specification

[joswang <joswang1221@gmail.com>]

From: Jos Wang <joswang@lenovo.com>

According to the USB PD3 CTS specification
(https://usb.org/document-library/
usb-power-delivery-compliance-test-specification-0/
USB_PD3_CTS_Q4_2024_OR.zip), the requirements for
tSenderResponse are different in PD2 and PD3 modes, see
Table 19 Timing Table & Calculations. For PD2 mode, the
tSenderResponse min 24ms and max 30ms; for PD3 mode, the
tSenderResponse min 27ms and max 33ms.

For the "TEST.PD.PROT.SRC.2 Get_Source_Cap No Request" test
item, after receiving the Source_Capabilities Message sent by
the UUT, the tester deliberately does not send a Request Message
in order to force the SenderResponse timer on the Source UUT to
timeout. The Tester checks that a Hard Reset is detected between
tSenderResponse min and max，the delay is between the last bit of
the GoodCRC Message EOP has been sent and the first bit of Hard
Reset SOP has been received. The current code does not distinguish
between PD2 and PD3 modes, and tSenderResponse defaults to 60ms.
This will cause this test item and the following tests to fail:
TEST.PD.PROT.SRC3.2 SenderResponseTimer Timeout
TEST.PD.PROT.SNK.6 SenderResponseTimer Timeout

Set the SenderResponseTimer timeout to 27ms to meet the PD2
and PD3 mode requirements.

Fixes: f0690a25a140 ("staging: typec: USB Type-C Port Manager (tcpm)")
Cc: stable@vger.kernel.org
Signed-off-by: Jos Wang <joswang@lenovo.com>
---
 include/linux/usb/pd.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h
index 3068c3084eb6..99ca49bbf376 100644
--- a/include/linux/usb/pd.h
+++ b/include/linux/usb/pd.h
@@ -475,7 +475,7 @@ static inline unsigned int rdo_max_power(u32 rdo)
 #define PD_T_NO_RESPONSE	5000	/* 4.5 - 5.5 seconds */
 #define PD_T_DB_DETECT		10000	/* 10 - 15 seconds */
 #define PD_T_SEND_SOURCE_CAP	150	/* 100 - 200 ms */
-#define PD_T_SENDER_RESPONSE	60	/* 24 - 30 ms, relaxed */
+#define PD_T_SENDER_RESPONSE	27	/* 24 - 30 ms */
 #define PD_T_RECEIVER_RESPONSE	15	/* 15ms max */
 #define PD_T_SOURCE_ACTIVITY	45
 #define PD_T_SINK_ACTIVITY	135
-- 
2.17.1