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From:   Prashant Malani <pmalani@chromium.org>
To:     linux-kernel@vger.kernel.org
Cc:     heikki.krogerus@linux.intel.com,
        Prashant Malani <pmalani@chromium.org>,
        Benson Leung <bleung@chromium.org>,
        Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        Guenter Roeck <groeck@chromium.org>
Subject: [PATCH v4 1/2] platform/chrome: cros_ec_typec: Use workqueue for port update
Date:   Mon, 29 Jun 2020 14:13:27 -0700
Message-Id: <20200629211329.2185342-1-pmalani@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Use a work queue to call the port update routines, instead of doing it
directly in the PD notifier callback. This will prevent other drivers
with PD notifier callbacks from being blocked on the port update routine
completing.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
---

Changes in v4:
- Removed extra newline.
- Moved both variable declarations into one line.

Changes in v3:
- Use new 100 character line length limit.

Changes in v2:
- No changes.

 drivers/platform/chrome/cros_ec_typec.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
index 0c041b79cbba..69c4118e280c 100644
--- a/drivers/platform/chrome/cros_ec_typec.c
+++ b/drivers/platform/chrome/cros_ec_typec.c
@@ -58,6 +58,7 @@ struct cros_typec_data {
 	/* Array of ports, indexed by port number. */
 	struct cros_typec_port *ports[EC_USB_PD_MAX_PORTS];
 	struct notifier_block nb;
+	struct work_struct port_work;
 };
 
 static int cros_typec_parse_port_props(struct typec_capability *cap,
@@ -619,18 +620,24 @@ static int cros_typec_get_cmd_version(struct cros_typec_data *typec)
 	return 0;
 }
 
-static int cros_ec_typec_event(struct notifier_block *nb,
-			       unsigned long host_event, void *_notify)
+static void cros_typec_port_work(struct work_struct *work)
 {
-	struct cros_typec_data *typec = container_of(nb, struct cros_typec_data,
-						     nb);
-	int ret, i;
+	struct cros_typec_data *typec = container_of(work, struct cros_typec_data, port_work);
+	int i, ret;
 
 	for (i = 0; i < typec->num_ports; i++) {
 		ret = cros_typec_port_update(typec, i);
 		if (ret < 0)
 			dev_warn(typec->dev, "Update failed for port: %d\n", i);
 	}
+}
+
+static int cros_ec_typec_event(struct notifier_block *nb,
+			       unsigned long host_event, void *_notify)
+{
+	struct cros_typec_data *typec = container_of(nb, struct cros_typec_data, nb);
+
+	schedule_work(&typec->port_work);
 
 	return NOTIFY_OK;
 }
@@ -689,6 +696,12 @@ static int cros_typec_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;
 
+	INIT_WORK(&typec->port_work, cros_typec_port_work);
+
+	/*
+	 * Safe to call port update here, since we haven't registered the
+	 * PD notifier yet.
+	 */
 	for (i = 0; i < typec->num_ports; i++) {
 		ret = cros_typec_port_update(typec, i);
 		if (ret < 0)
-- 
2.27.0.212.ge8ba1cc988-goog