linux-kernel - [PATCH v2 1/2] platform/chrome: cros_ec

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Message-ID: <20250711003502.857536-1-raduvele@google.com>
Date: Fri, 11 Jul 2025 00:35:01 +0000
From: Radu Vele <raduvele@...gle.com>
To: Benson Leung <bleung@...omium.org>, 
	Abhishek Pandit-Subedi <abhishekpandit@...omium.org>, Jameson Thies <jthies@...gle.com>, 
	Andrei Kuchynski <akuchynski@...omium.org>, Tzung-Bi Shih <tzungbi@...nel.org>
Cc: chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/2] platform/chrome: cros_ec_typec: Add role swap ops

From: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>

Add the pr_set and dr_set typec_operations to registered typec ports.
This enables sysfs to control power and data role when the port is
capable of doing so.

Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
Co-developed-by: Radu Vele <raduvele@...gle.com>
Signed-off-by: Radu Vele <raduvele@...gle.com>

---
  Changes in v2:
    - addressed comments from Tzung-Bi
    - after EC command to swap role is issued we check if the returned
      role in the response matches the target role. While testing this
      I observed that for power role swap the ec returns >0 but the
      returned role doesn't ever match the target role (but the role
      swap happens as expected). This may be an EC bug, I am
      investigating.
---
 drivers/platform/chrome/cros_ec_typec.c | 85 ++++++++++++++++++++++++-
 1 file changed, 84 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
index 7678e3d05fd3..e689bfaf95dc 100644
--- a/drivers/platform/chrome/cros_ec_typec.c
+++ b/drivers/platform/chrome/cros_ec_typec.c
@@ -58,8 +58,91 @@ static int cros_typec_enter_usb_mode(struct typec_port *tc_port, enum usb_mode m
 			  &req, sizeof(req), NULL, 0);
 }
 
+static int cros_typec_perform_role_swap(struct typec_port *tc_port, int target_role, u8 swap_type)
+{
+	struct cros_typec_port *port = typec_get_drvdata(tc_port);
+	struct cros_typec_data *data = port->typec_data;
+	struct ec_response_usb_pd_control_v2 resp;
+	struct ec_params_usb_pd_control req;
+	int role, ret;
+
+	/* Must be at least v1 to support role swap. */
+	if (!data->pd_ctrl_ver)
+		return -EOPNOTSUPP;
+
+	/* First query the state */
+	req.port = port->port_num;
+	req.role = USB_PD_CTRL_ROLE_NO_CHANGE;
+	req.mux = USB_PD_CTRL_MUX_NO_CHANGE;
+	req.swap = USB_PD_CTRL_SWAP_NONE;
+
+	ret = cros_ec_cmd(data->ec, data->pd_ctrl_ver, EC_CMD_USB_PD_CONTROL,
+				&req, sizeof(req), &resp, sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	switch (swap_type) {
+	case USB_PD_CTRL_SWAP_DATA:
+		role = (resp.role & PD_CTRL_RESP_ROLE_DATA) ? TYPEC_HOST :
+						TYPEC_DEVICE;
+		break;
+	case USB_PD_CTRL_SWAP_POWER:
+		role = (resp.role & PD_CTRL_RESP_ROLE_POWER) ? TYPEC_SOURCE :
+						TYPEC_SINK;
+		break;
+	default:
+		dev_warn(data->dev, "Unsupported role swap type %d\n", swap_type);
+		return -EOPNOTSUPP;
+	}
+
+	if (role == target_role)
+		return 0;
+
+	req.swap = swap_type;
+	ret = cros_ec_cmd(data->ec, data->pd_ctrl_ver, EC_CMD_USB_PD_CONTROL,
+				&req, sizeof(req), &resp, sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	switch (swap_type) {
+	case USB_PD_CTRL_SWAP_DATA:
+		role = resp.role & PD_CTRL_RESP_ROLE_DATA ? TYPEC_HOST : TYPEC_DEVICE;
+		if (role != target_role) {
+			dev_err(data->dev, "Data role swap failed despite EC returning success\n");
+			return -EIO;
+		}
+		typec_set_data_role(tc_port, target_role);
+		break;
+	case USB_PD_CTRL_SWAP_POWER:
+		role = resp.role & PD_CTRL_RESP_ROLE_POWER ? TYPEC_SOURCE : TYPEC_SINK;
+		if (role != target_role) {
+			dev_err(data->dev, "Power role swap failed despite EC returning success\n");
+			return -EIO;
+		}
+		typec_set_pwr_role(tc_port, target_role);
+		break;
+	default:
+		/* Should never execute */
+		break;
+	}
+
+	return 0;
+}
+
+static int cros_typec_dr_swap(struct typec_port *port, enum typec_data_role role)
+{
+	return cros_typec_perform_role_swap(port, role, USB_PD_CTRL_SWAP_DATA);
+}
+
+static int cros_typec_pr_swap(struct typec_port *port, enum typec_role role)
+{
+	return cros_typec_perform_role_swap(port, role, USB_PD_CTRL_SWAP_POWER);
+}
+
 static const struct typec_operations cros_typec_usb_mode_ops = {
-	.enter_usb_mode = cros_typec_enter_usb_mode
+	.enter_usb_mode = cros_typec_enter_usb_mode,
+	.dr_set = cros_typec_dr_swap,
+	.pr_set = cros_typec_pr_swap,
 };
 
 static int cros_typec_parse_port_props(struct typec_capability *cap,
-- 
2.50.0.727.gbf7dc18ff4-goog