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Date:   Mon, 15 Aug 2022 20:33:55 -0700
Message-Id: <20220816033355.1259400-1-badhri@google.com>
Mime-Version: 1.0
Subject: [PATCH v1] usb: typec: tcpm: Return ENOTSUPP for power supply prop writes
From:   Badhri Jagan Sridharan <badhri@google.com>
To:     Guenter Roeck <linux@roeck-us.net>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Kyle Tso <kyletso@google.com>, stable@vger.kernel.org,
        Badhri Jagan Sridharan <badhri@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

When the port does not support USB PD, prevent transition to PD
only states when power supply property is written. In this case,
TCPM transitions to SNK_NEGOTIATE_CAPABILITIES
which should not be the case given that the port is not pd_capable.

[   84.308251] state change SNK_READY -> SNK_NEGOTIATE_CAPABILITIES [rev3 NONE_AMS]
[   84.308335] Setting usb_comm capable false
[   84.323367] set_auto_vbus_discharge_threshold mode:3 pps_active:n vbus:5000 ret:0
[   84.323376] state change SNK_NEGOTIATE_CAPABILITIES -> SNK_WAIT_CAPABILITIES [rev3 NONE_AMS]

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index ea5a917c51b1..904c7b4ce2f0 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -6320,6 +6320,13 @@ static int tcpm_psy_set_prop(struct power_supply *psy,
 	struct tcpm_port *port = power_supply_get_drvdata(psy);
 	int ret;
 
+	/*
+	 * All the properties below are related to USB PD. The check needs to be
+	 * property specific when a non-pd related property is added.
+	 */
+	if (!port->pd_supported)
+		return -EOPNOTSUPP;
+
 	switch (psp) {
 	case POWER_SUPPLY_PROP_ONLINE:
 		ret = tcpm_psy_set_online(port, val);
-- 
2.37.1.595.g718a3a8f04-goog