[v3,5/7] platform/chrome: cros_ec_typec: Displayport support

diff --git a/MAINTAINERS b/MAINTAINERS
index cd6aa609deba..5f9d8b8f1cb3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5369,9 +5369,12 @@  F:	include/linux/platform_data/cros_usbpd_notify.h
 
 CHROMEOS EC USB TYPE-C DRIVER
 M:	Prashant Malani <pmalani@chromium.org>
+M:	Benson Leung <bleung@chromium.org>
+M:	Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
 L:	chrome-platform@lists.linux.dev
 S:	Maintained
 F:	drivers/platform/chrome/cros_ec_typec.*
+F:	drivers/platform/chrome/cros_typec_altmode.*
 F:	drivers/platform/chrome/cros_typec_switch.c
 F:	drivers/platform/chrome/cros_typec_vdm.*
 
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 2dcc6ccc2302..2f90d4db8099 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -18,7 +18,11 @@  obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
 obj-$(CONFIG_CROS_EC_UART)		+= cros_ec_uart.o
 cros_ec_lpcs-objs			:= cros_ec_lpc.o cros_ec_lpc_mec.o
 cros-ec-typec-objs			:= cros_ec_typec.o cros_typec_vdm.o
+ifneq ($(CONFIG_TYPEC_DP_ALTMODE),)
+	cros-ec-typec-objs		+= cros_typec_altmode.o
+endif
 obj-$(CONFIG_CROS_EC_TYPEC)		+= cros-ec-typec.o
+
 obj-$(CONFIG_CROS_EC_LPC)		+= cros_ec_lpcs.o
 obj-$(CONFIG_CROS_EC_PROTO)		+= cros_ec_proto.o cros_ec_trace.o
 obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)	+= cros_kbd_led_backlight.o
diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
index e3eabe5e42ac..3a6f5f2717b9 100644
--- a/drivers/platform/chrome/cros_ec_typec.c
+++ b/drivers/platform/chrome/cros_ec_typec.c
@@ -18,6 +18,7 @@ 
 
 #include "cros_ec_typec.h"
 #include "cros_typec_vdm.h"
+#include "cros_typec_altmode.h"
 
 #define DRV_NAME "cros-ec-typec"
 
@@ -293,12 +294,11 @@  static int cros_typec_register_port_altmodes(struct cros_typec_data *typec,
 	desc.svid = USB_TYPEC_DP_SID;
 	desc.mode = USB_TYPEC_DP_MODE;
 	desc.vdo = DP_PORT_VDO;
-	amode = typec_port_register_altmode(port->port, &desc);
+	amode = cros_typec_register_displayport(port, &desc,
+						typec->ap_driven_altmode);
 	if (IS_ERR(amode))
 		return PTR_ERR(amode);
 	port->port_altmode[CROS_EC_ALTMODE_DP] = amode;
-	typec_altmode_set_drvdata(amode, port);
-	amode->ops = &port_amode_ops;
 
 	/*
 	 * Register TBT compatibility alt mode. The EC will not enter the mode
@@ -575,6 +575,10 @@  static int cros_typec_enable_dp(struct cros_typec_data *typec,
 	if (!ret)
 		ret = typec_mux_set(port->mux, &port->state);
 
+	if (!ret)
+		cros_typec_displayport_status_update(port->state.alt,
+						     port->state.data);
+
 	return ret;
 }
 
@@ -1254,6 +1258,8 @@  static int cros_typec_probe(struct platform_device *pdev)
 
 	typec->typec_cmd_supported = cros_ec_check_features(ec_dev, EC_FEATURE_TYPEC_CMD);
 	typec->needs_mux_ack = cros_ec_check_features(ec_dev, EC_FEATURE_TYPEC_MUX_REQUIRE_AP_ACK);
+	typec->ap_driven_altmode = cros_ec_check_features(
+		ec_dev, EC_FEATURE_TYPEC_REQUIRE_AP_MODE_ENTRY);
 
 	ret = cros_ec_cmd(typec->ec, 0, EC_CMD_USB_PD_PORTS, NULL, 0,
 			  &resp, sizeof(resp));
diff --git a/drivers/platform/chrome/cros_ec_typec.h b/drivers/platform/chrome/cros_ec_typec.h
index deda180a646f..9fd5342bb0ad 100644
--- a/drivers/platform/chrome/cros_ec_typec.h
+++ b/drivers/platform/chrome/cros_ec_typec.h
@@ -39,6 +39,7 @@  struct cros_typec_data {
 	struct work_struct port_work;
 	bool typec_cmd_supported;
 	bool needs_mux_ack;
+	bool ap_driven_altmode;
 };
 
 /* Per port data. */
diff --git a/drivers/platform/chrome/cros_typec_altmode.c b/drivers/platform/chrome/cros_typec_altmode.c
new file mode 100644
index 000000000000..3598b8a6ceee
--- /dev/null
+++ b/drivers/platform/chrome/cros_typec_altmode.c
@@ -0,0 +1,275 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Alt-mode implementation on ChromeOS EC.
+ *
+ * Copyright 2024 Google LLC
+ * Author: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
+ */
+#include "cros_ec_typec.h"
+
+#include <linux/usb/typec_dp.h>
+#include <linux/usb/pd_vdo.h>
+
+#include "cros_typec_altmode.h"
+
+struct cros_typec_altmode_data {
+	struct work_struct work;
+	struct cros_typec_port *port;
+	struct typec_altmode *alt;
+	bool ap_mode_entry;
+
+	u32 header;
+	u32 *vdo_data;
+	u8 vdo_size;
+
+	u16 sid;
+	u8 mode;
+};
+
+struct cros_typec_dp_data {
+	struct cros_typec_altmode_data adata;
+	struct typec_displayport_data data;
+	bool configured;
+	bool pending_status_update;
+};
+
+static void cros_typec_altmode_work(struct work_struct *work)
+{
+	struct cros_typec_altmode_data *data =
+		container_of(work, struct cros_typec_altmode_data, work);
+
+	if (typec_altmode_vdm(data->alt, data->header, data->vdo_data,
+			      data->vdo_size))
+		dev_err(&data->alt->dev, "VDM 0x%x failed", data->header);
+
+	data->header = 0;
+	data->vdo_data = NULL;
+	data->vdo_size = 0;
+}
+
+static int cros_typec_altmode_enter(struct typec_altmode *alt, u32 *vdo)
+{
+	struct cros_typec_altmode_data *data = typec_altmode_get_drvdata(alt);
+	struct ec_params_typec_control req = {
+		.port = data->port->port_num,
+		.command = TYPEC_CONTROL_COMMAND_ENTER_MODE,
+	};
+	int svdm_version;
+	int ret;
+
+	if (!data->ap_mode_entry) {
+		const struct typec_altmode *partner =
+			typec_altmode_get_partner(alt);
+		dev_warn(&partner->dev,
+			 "EC does not support ap driven mode entry\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (data->sid == USB_TYPEC_DP_SID)
+		req.mode_to_enter = CROS_EC_ALTMODE_DP;
+	else
+		return -EOPNOTSUPP;
+
+	ret = cros_ec_cmd(data->port->typec_data->ec, 0, EC_CMD_TYPEC_CONTROL,
+			  &req, sizeof(req), NULL, 0);
+	if (ret < 0)
+		return ret;
+
+	svdm_version = typec_altmode_get_svdm_version(alt);
+	if (svdm_version < 0)
+		return svdm_version;
+
+	data->header = VDO(data->sid, 1, svdm_version, CMD_ENTER_MODE);
+	data->header |= VDO_OPOS(data->mode);
+	data->header |= VDO_CMDT(CMDT_RSP_ACK);
+
+	data->vdo_data = NULL;
+	data->vdo_size = 1;
+
+	schedule_work(&data->work);
+
+	return ret;
+}
+
+static int cros_typec_altmode_exit(struct typec_altmode *alt)
+{
+	struct cros_typec_altmode_data *data = typec_altmode_get_drvdata(alt);
+	struct ec_params_typec_control req = {
+		.port = data->port->port_num,
+		.command = TYPEC_CONTROL_COMMAND_EXIT_MODES,
+	};
+	int svdm_version;
+	int ret;
+
+	if (!data->ap_mode_entry) {
+		const struct typec_altmode *partner =
+			typec_altmode_get_partner(alt);
+		dev_warn(&partner->dev,
+			 "EC does not support ap driven mode entry\n");
+		return -EOPNOTSUPP;
+	}
+
+	ret = cros_ec_cmd(data->port->typec_data->ec, 0, EC_CMD_TYPEC_CONTROL,
+			  &req, sizeof(req), NULL, 0);
+
+	if (ret < 0)
+		return ret;
+
+	svdm_version = typec_altmode_get_svdm_version(alt);
+	if (svdm_version < 0)
+		return svdm_version;
+
+	data->header = VDO(data->sid, 1, svdm_version, CMD_EXIT_MODE);
+	data->header |= VDO_OPOS(data->mode);
+	data->header |= VDO_CMDT(CMDT_RSP_ACK);
+
+	data->vdo_data = NULL;
+	data->vdo_size = 1;
+
+	schedule_work(&data->work);
+
+	return ret;
+}
+
+static int cros_typec_displayport_vdm(struct typec_altmode *alt, u32 header,
+				      const u32 *data, int count)
+{
+	struct cros_typec_dp_data *dp_data = typec_altmode_get_drvdata(alt);
+	struct cros_typec_altmode_data *adata = &dp_data->adata;
+
+
+	int cmd_type = PD_VDO_CMDT(header);
+	int cmd = PD_VDO_CMD(header);
+	int svdm_version;
+
+	if (!adata->ap_mode_entry) {
+		const struct typec_altmode *partner =
+			typec_altmode_get_partner(alt);
+		dev_warn(&partner->dev,
+			 "EC does not support ap driven mode entry\n");
+		return -EOPNOTSUPP;
+	}
+
+	svdm_version = typec_altmode_get_svdm_version(alt);
+	if (svdm_version < 0)
+		return svdm_version;
+
+	switch (cmd_type) {
+	case CMDT_INIT:
+		if (PD_VDO_SVDM_VER(header) < svdm_version) {
+			typec_partner_set_svdm_version(adata->port->partner,
+						       PD_VDO_SVDM_VER(header));
+			svdm_version = PD_VDO_SVDM_VER(header);
+		}
+
+		adata->header = VDO(adata->sid, 1, svdm_version, cmd);
+		adata->header |= VDO_OPOS(adata->mode);
+
+		/*
+		 * DP_CMD_CONFIGURE: We can't actually do anything with the
+		 * provided VDO yet so just send back an ACK.
+		 *
+		 * DP_CMD_STATUS_UPDATE: We wait for Mux changes to send
+		 * DPStatus Acks.
+		 */
+		switch (cmd) {
+		case DP_CMD_CONFIGURE:
+			dp_data->data.conf = *data;
+			adata->header |= VDO_CMDT(CMDT_RSP_ACK);
+			dp_data->configured = true;
+			schedule_work(&adata->work);
+			break;
+		case DP_CMD_STATUS_UPDATE:
+			dp_data->pending_status_update = true;
+			break;
+		default:
+			adata->header |= VDO_CMDT(CMDT_RSP_ACK);
+			schedule_work(&adata->work);
+			break;
+		}
+
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int cros_typec_altmode_vdm(struct typec_altmode *alt, u32 header,
+				      const u32 *data, int count)
+{
+	struct cros_typec_altmode_data *adata = typec_altmode_get_drvdata(alt);
+
+	if (adata->sid == USB_TYPEC_DP_SID)
+		return cros_typec_displayport_vdm(alt, header, data, count);
+
+	return -EINVAL;
+}
+
+static const struct typec_altmode_ops cros_typec_altmode_ops = {
+	.enter = cros_typec_altmode_enter,
+	.exit = cros_typec_altmode_exit,
+	.vdm = cros_typec_altmode_vdm,
+};
+
+#if IS_ENABLED(CONFIG_TYPEC_DP_ALTMODE)
+int cros_typec_displayport_status_update(struct typec_altmode *altmode,
+					 struct typec_displayport_data *data)
+{
+	struct cros_typec_dp_data *dp_data =
+		typec_altmode_get_drvdata(altmode);
+	struct cros_typec_altmode_data *adata = &dp_data->adata;
+
+	if (!dp_data->pending_status_update) {
+		dev_dbg(&altmode->dev,
+			"Got DPStatus without a pending request");
+		return 0;
+	}
+
+	if (dp_data->configured && dp_data->data.conf != data->conf)
+		dev_dbg(&altmode->dev,
+			"DP Conf doesn't match. Requested 0x%04x, Actual 0x%04x",
+			dp_data->data.conf, data->conf);
+
+	dp_data->data = *data;
+	dp_data->pending_status_update = false;
+	adata->header |= VDO_CMDT(CMDT_RSP_ACK);
+	adata->vdo_data = &dp_data->data.status;
+	adata->vdo_size = 2;
+
+	schedule_work(&adata->work);
+	return 0;
+}
+
+struct typec_altmode *
+cros_typec_register_displayport(struct cros_typec_port *port,
+				struct typec_altmode_desc *desc,
+				bool ap_mode_entry)
+{
+	struct typec_altmode *alt;
+	struct cros_typec_altmode_data *data;
+
+	alt = typec_port_register_altmode(port->port, desc);
+	if (IS_ERR(alt))
+		return alt;
+
+	data = devm_kzalloc(&alt->dev, sizeof(*data), GFP_KERNEL);
+	if (!data) {
+		typec_unregister_altmode(alt);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	INIT_WORK(&data->work, cros_typec_altmode_work);
+	data->alt = alt;
+	data->port = port;
+	data->ap_mode_entry = ap_mode_entry;
+	data->sid = desc->svid;
+	data->mode = desc->mode;
+
+	typec_altmode_set_ops(alt, &cros_typec_altmode_ops);
+	typec_altmode_set_drvdata(alt, data);
+
+	return alt;
+}
+#endif
diff --git a/drivers/platform/chrome/cros_typec_altmode.h b/drivers/platform/chrome/cros_typec_altmode.h
new file mode 100644
index 000000000000..c6f8fb02c99c
--- /dev/null
+++ b/drivers/platform/chrome/cros_typec_altmode.h
@@ -0,0 +1,34 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __CROS_TYPEC_ALTMODE_H__
+#define __CROS_TYPEC_ALTMODE_H__
+
+struct cros_typec_port;
+struct typec_altmode;
+struct typec_altmode_desc;
+struct typec_displayport_data;
+
+#if IS_ENABLED(CONFIG_TYPEC_DP_ALTMODE)
+struct typec_altmode *
+cros_typec_register_displayport(struct cros_typec_port *port,
+				struct typec_altmode_desc *desc,
+				bool ap_mode_entry);
+
+int cros_typec_displayport_status_update(struct typec_altmode *altmode,
+					 struct typec_displayport_data *data);
+#else
+static inline struct typec_altmode *
+cros_typec_register_displayport(struct cros_typec_port *port,
+				struct typec_altmode_desc *desc,
+				bool ap_mode_entry)
+{
+	return typec_port_register_altmode(port->port, desc);
+}
+
+static inline int cros_typec_displayport_status_update(struct typec_altmode *altmode,
+					 struct typec_displayport_data *data)
+{
+	return 0;
+}
+#endif
+#endif /* __CROS_TYPEC_ALTMODE_H__ */