linux-kernel - [PATCH 6/9] platform/chrome: cros_typec

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Message-Id: <20220629233314.3540377-7-pmalani@chromium.org>
Date:   Wed, 29 Jun 2022 23:32:24 +0000
From:   Prashant Malani <pmalani@...omium.org>
To:     linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
        chrome-platform@...ts.linux.dev
Cc:     bleung@...omium.org, heikki.krogerus@...ux.intel.com,
        Prashant Malani <pmalani@...omium.org>,
        Daisuke Nojiri <dnojiri@...omium.org>,
        "Dustin L. Howett" <dustin@...ett.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Guenter Roeck <groeck@...omium.org>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        Sebastian Reichel <sebastian.reichel@...labora.com>,
        Tzung-Bi Shih <tzungbi@...nel.org>
Subject: [PATCH 6/9] platform/chrome: cros_typec_switch: Add event check

The Chrome 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@...omium.org>
---
 drivers/platform/chrome/cros_typec_switch.c | 72 ++++++++++++++++++++-
 1 file changed, 70 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/chrome/cros_typec_switch.c b/drivers/platform/chrome/cros_typec_switch.c
index 9faa442dd81a..a226f828514f 100644
--- a/drivers/platform/chrome/cros_typec_switch.c
+++ b/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>
@@ -63,6 +65,40 @@ 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_command(sdata->ec, 0, EC_CMD_TYPEC_CONTROL, &req,
+			       sizeof(req), NULL, 0);
+}
+
+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_command(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 Chrome 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
@@ -71,12 +107,44 @@ 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;
+
+	/* Send the set command. */
+	ret = cros_typec_cmd_mux_set(sdata, port_num, index, mux_state);
 	if (ret < 0)
 		return ret;
 
-	return cros_typec_cmd_mux_set(sdata, port_num, index, (u8)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
-- 
2.37.0.rc0.161.g10f37bed90-goog