platform/chrome: cros_typec_switch: Add event check

The ChromeOS EC updates Type-C status events when mux set requests from
the Application Processor (AP) are completed. Add a check to the
flow of configuring muxes to look for this status done bit, so that
the driver is aware that the mux set completed successfully or not.
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20220816214857.2088914-5-pmalani@chromium.org

drivers/platform/chrome/cros_typec_switch.c

@@ -7,6 +7,8 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
 #include <linux/module.h>
 #include <linux/platform_data/cros_ec_commands.h>
 #include <linux/platform_data/cros_ec_proto.h>
@@ -60,6 +62,39 @@ static int cros_typec_get_mux_state(unsigned long mode, struct typec_altmode *al
 	return ret;
 }
 
+static int cros_typec_send_clear_event(struct cros_typec_switch_data *sdata, int port_num,
+				       u32 events_mask)
+{
+	struct ec_params_typec_control req = {
+		.port = port_num,
+		.command = TYPEC_CONTROL_COMMAND_CLEAR_EVENTS,
+		.clear_events_mask = events_mask,
+	};
+
+	return cros_ec_cmd(sdata->ec, 0, EC_CMD_TYPEC_CONTROL, &req, sizeof(req), NULL, 0);
+}
+
+static bool cros_typec_check_event(struct cros_typec_switch_data *sdata, int port_num, u32 mask)
+{
+	struct ec_response_typec_status resp;
+	struct ec_params_typec_status req = {
+		.port = port_num,
+	};
+	int ret;
+
+	ret = cros_ec_cmd(sdata->ec, 0, EC_CMD_TYPEC_STATUS, &req, sizeof(req),
+			  &resp, sizeof(resp));
+	if (ret < 0) {
+		dev_warn(sdata->dev, "EC_CMD_TYPEC_STATUS failed for port: %d\n", port_num);
+		return false;
+	}
+
+	if (resp.events & mask)
+		return true;
+
+	return false;
+}
+
 /*
  * The ChromeOS EC treats both mode-switches and retimers as "muxes" for the purposes of the
  * host command API. This common function configures and verifies the retimer/mode-switch
@@ -68,12 +103,44 @@ static int cros_typec_get_mux_state(unsigned long mode, struct typec_altmode *al
 static int cros_typec_configure_mux(struct cros_typec_switch_data *sdata, int port_num, int index,
 				    unsigned long mode, struct typec_altmode *alt)
 {
-	int ret = cros_typec_get_mux_state(mode, alt);
+	unsigned long end;
+	u32 event_mask;
+	u8 mux_state;
+	int ret;
+
+	ret = cros_typec_get_mux_state(mode, alt);
+	if (ret < 0)
+		return ret;
+	mux_state = (u8)ret;
+
+	/* Clear any old mux set done event. */
+	if (index == 0)
+		event_mask = PD_STATUS_EVENT_MUX_0_SET_DONE;
+	else
+		event_mask = PD_STATUS_EVENT_MUX_1_SET_DONE;
 
+	ret = cros_typec_send_clear_event(sdata, port_num, event_mask);
 	if (ret < 0)
 		return ret;
 
-	return cros_typec_cmd_mux_set(sdata, port_num, index, (u8)ret);
+	/* Send the set command. */
+	ret = cros_typec_cmd_mux_set(sdata, port_num, index, mux_state);
+	if (ret < 0)
+		return ret;
+
+	/* Check for the mux set done event. */
+	end = jiffies + msecs_to_jiffies(1000);
+	do {
+		if (cros_typec_check_event(sdata, port_num, event_mask))
+			return 0;
+
+		usleep_range(500, 1000);
+	} while (time_before(jiffies, end));
+
+	dev_err(sdata->dev, "Timed out waiting for mux set done on index: %d, state: %d\n",
+		index, mux_state);
+
+	return -ETIMEDOUT;
 }
 
 static int cros_typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)