linux-kernel - [PATCH v2] usb: typec: mux: intel: Handle alt mode HPD

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Date:   Tue, 28 Apr 2020 22:44:28 -0700
From:   Prashant Malani <pmalani@...omium.org>
To:     linux-kernel@...r.kernel.org
Cc:     heikki.krogerus@...ux.intel.com, bleung@...omium.org,
        Prashant Malani <pmalani@...omium.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org (open list:USB TYPEC CLASS)
Subject: [PATCH v2] usb: typec: mux: intel: Handle alt mode HPD_HIGH

According to the PMC Type C Subsystem (TCSS) Mux programming guide rev
0.6, when a device is transitioning to DP Alternate Mode state, if the
HPD_STATE (bit 7) field in the status update command VDO is set to
HPD_HIGH, the HPD_HIGH field in the Alternate Mode request “mode_data”
field (bit 14) should also be set. Ensure the bit is correctly handled
while issuing the Alternate Mode request.

Signed-off-by: Prashant Malani <pmalani@...omium.org>
Fixes: 6701adfa9693 ("usb: typec: driver for Intel PMC mux control")
---

Changes in v2:
- Clarified the commit message to mention the proper field names.

 drivers/usb/typec/mux/intel_pmc_mux.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/typec/mux/intel_pmc_mux.c b/drivers/usb/typec/mux/intel_pmc_mux.c
index f5c5e0aef66f..c599112559e7 100644
--- a/drivers/usb/typec/mux/intel_pmc_mux.c
+++ b/drivers/usb/typec/mux/intel_pmc_mux.c
@@ -157,6 +157,10 @@ pmc_usb_mux_dp(struct pmc_usb_port *port, struct typec_mux_state *state)
 	req.mode_data |= (state->mode - TYPEC_STATE_MODAL) <<
 			 PMC_USB_ALTMODE_DP_MODE_SHIFT;
 
+	if (data->status & DP_STATUS_HPD_STATE)
+		req.mode_data |= PMC_USB_DP_HPD_LVL <<
+				 PMC_USB_ALTMODE_DP_MODE_SHIFT;
+
 	return pmc_usb_command(port, (void *)&req, sizeof(req));
 }
 
-- 
2.26.2.303.gf8c07b1a785-goog