linux-kernel - [PATCH v1] usb: typec: intel_pmc_mux: Configure HPD first for HPD+IRQ request

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Message-Id: <20201216140918.49197-1-madhusudanarao.amara@intel.com>
Date:   Wed, 16 Dec 2020 19:39:18 +0530
From:   Madhusudanarao Amara <madhusudanarao.amara@...el.com>
To:     heikki.krogerus@...el.com, gregkh@...uxfoundation.org,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     heikki.krogerus@...ux.intel.com, madhusudanarao.amara@...el.com
Subject: [PATCH v1] usb: typec: intel_pmc_mux: Configure HPD first for HPD+IRQ request

Warm reboot scenarios some times type C Mux driver gets Mux configuration
request as HPD=1,IRQ=1. In that scenario typeC Mux driver need to configure
Mux as follows as per IOM requirement:
 (1). Confgiure Mux HPD = 1, IRQ = 0
 (2). Configure Mux with HPD = 1, IRQ = 1

IOM expects TypeC Mux configuration as follows:
 (1). HPD=1, IRQ=0
 (2). HPD=1, IRQ=1
if IOM gets mux config request (2) without configuring (1), it will ignore
the request. The impact of this is there is no DP_alt mode display.

Fixes: 43d596e32276 ("usb: typec: intel_pmc_mux: Check the port status before connect")
Cc: stable@...r.kernel.org
Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Signed-off-by: Madhusudanarao Amara <madhusudanarao.amara@...el.com>
---
 drivers/usb/typec/mux/intel_pmc_mux.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/usb/typec/mux/intel_pmc_mux.c b/drivers/usb/typec/mux/intel_pmc_mux.c
index cf37a59ce130..46a25b8db72e 100644
--- a/drivers/usb/typec/mux/intel_pmc_mux.c
+++ b/drivers/usb/typec/mux/intel_pmc_mux.c
@@ -207,10 +207,21 @@ static int
 pmc_usb_mux_dp_hpd(struct pmc_usb_port *port, struct typec_displayport_data *dp)
 {
 	u8 msg[2] = { };
+	int ret;
 
 	msg[0] = PMC_USB_DP_HPD;
 	msg[0] |= port->usb3_port << PMC_USB_MSG_USB3_PORT_SHIFT;
 
+	/* Configure HPD first if HPD,IRQ comes together */
+	if (!IOM_PORT_HPD_ASSERTED(port->iom_status) &&
+	    dp->status & DP_STATUS_IRQ_HPD &&
+	    dp->status & DP_STATUS_HPD_STATE) {
+		msg[1] = PMC_USB_DP_HPD_LVL;
+		ret = pmc_usb_command(port, msg, sizeof(msg));
+		if (ret)
+			return ret;
+	}
+
 	if (dp->status & DP_STATUS_IRQ_HPD)
 		msg[1] = PMC_USB_DP_HPD_IRQ;
 
-- 
2.17.1