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From:   Aswath Govindraju <a-govindraju@ti.com>
CC:     Vignesh Raghavendra <vigneshr@ti.com>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Roger Quadros <rogerq@kernel.org>,
        Aswath Govindraju <a-govindraju@ti.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Sven Peter <sven@svenpeter.dev>,
        Alyssa Rosenzweig <alyssa@rosenzweig.io>,
        Hector Martin <marcan@marcan.st>,
        Saranya Gopal <saranya.gopal@intel.com>,
        Jens Axboe <axboe@kernel.dk>, <linux-usb@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH RFC] usb: typec: tipd: Add support for polling interrupts status when interrupt line is not connected
Date:   Tue, 12 Apr 2022 20:20:58 +0530
Message-ID: <20220412145059.4717-1-a-govindraju@ti.com>
MIME-Version: 1.0
Content-Type: text/plain
To:     unlisted-recipients:; (no To-header on input)
Precedence: bulk

In some cases the interrupt line from the pd controller may not be
connected. In these cases, poll the status of various events.

Suggested-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
---
 drivers/usb/typec/tipd/core.c | 90 ++++++++++++++++++++++++++++++++---
 1 file changed, 83 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/typec/tipd/core.c b/drivers/usb/typec/tipd/core.c
index 16b4560216ba..fa52d2067d6d 100644
--- a/drivers/usb/typec/tipd/core.c
+++ b/drivers/usb/typec/tipd/core.c
@@ -15,6 +15,8 @@
 #include <linux/interrupt.h>
 #include <linux/usb/typec.h>
 #include <linux/usb/role.h>
+#include <linux/workqueue.h>
+#include <linux/devm-helpers.h>
 
 #include "tps6598x.h"
 #include "trace.h"
@@ -93,6 +95,8 @@ struct tps6598x {
 	struct power_supply *psy;
 	struct power_supply_desc psy_desc;
 	enum power_supply_usb_type usb_type;
+
+	struct delayed_work wq_poll;
 };
 
 static enum power_supply_property tps6598x_psy_props[] = {
@@ -473,9 +477,8 @@ static void tps6598x_handle_plug_event(struct tps6598x *tps, u32 status)
 	}
 }
 
-static irqreturn_t cd321x_interrupt(int irq, void *data)
+static int cd321x_handle_interrupt_status(struct tps6598x *tps)
 {
-	struct tps6598x *tps = data;
 	u64 event;
 	u32 status;
 	int ret;
@@ -513,14 +516,45 @@ static irqreturn_t cd321x_interrupt(int irq, void *data)
 err_unlock:
 	mutex_unlock(&tps->lock);
 
+	if (ret)
+		return ret;
+
 	if (event)
-		return IRQ_HANDLED;
-	return IRQ_NONE;
+		return 0;
+	return 1;
 }
 
-static irqreturn_t tps6598x_interrupt(int irq, void *data)
+static irqreturn_t cd321x_interrupt(int irq, void *data)
 {
 	struct tps6598x *tps = data;
+	int ret;
+
+	ret = cd321x_handle_interrupt_status(tps);
+	if (ret)
+		return IRQ_NONE;
+	return IRQ_HANDLED;
+}
+
+/* Time interval for Polling */
+#define POLL_INTERVAL   500 /* msecs */
+static void cd321x_poll_work(struct work_struct *work)
+{
+	struct tps6598x *tps = container_of(to_delayed_work(work),
+					    struct tps6598x, wq_poll);
+	int ret;
+
+	ret = cd321x_handle_interrupt_status(tps);
+	/*
+	 * If there is an error while reading the interrupt registers
+	 * then stop polling else, schedule another poll work item
+	 */
+	if (!(ret < 0))
+		queue_delayed_work(system_power_efficient_wq,
+				   &tps->wq_poll, msecs_to_jiffies(POLL_INTERVAL));
+}
+
+static int tps6598x_handle_interrupt_status(struct tps6598x *tps)
+{
 	u64 event1;
 	u64 event2;
 	u32 status;
@@ -561,9 +595,39 @@ static irqreturn_t tps6598x_interrupt(int irq, void *data)
 err_unlock:
 	mutex_unlock(&tps->lock);
 
+	if (ret)
+		return ret;
+
 	if (event1 | event2)
-		return IRQ_HANDLED;
-	return IRQ_NONE;
+		return 0;
+	return 1;
+}
+
+static irqreturn_t tps6598x_interrupt(int irq, void *data)
+{
+	struct tps6598x *tps = data;
+	int ret;
+
+	ret = tps6598x_handle_interrupt_status(tps);
+	if (ret)
+		return IRQ_NONE;
+	return IRQ_HANDLED;
+}
+
+static void tps6598x_poll_work(struct work_struct *work)
+{
+	struct tps6598x *tps = container_of(to_delayed_work(work),
+					    struct tps6598x, wq_poll);
+	int ret;
+
+	ret = tps6598x_handle_interrupt_status(tps);
+	/*
+	 * If there is an error while reading the interrupt registers
+	 * then stop polling else, schedule another poll work item
+	 */
+	if (!(ret < 0))
+		queue_delayed_work(system_power_efficient_wq,
+				   &tps->wq_poll, msecs_to_jiffies(POLL_INTERVAL));
 }
 
 static int tps6598x_check_mode(struct tps6598x *tps)
@@ -704,6 +768,7 @@ static int devm_tps6598_psy_register(struct tps6598x *tps)
 static int tps6598x_probe(struct i2c_client *client)
 {
 	irq_handler_t irq_handler = tps6598x_interrupt;
+	work_func_t work_poll_handler = tps6598x_poll_work;
 	struct device_node *np = client->dev.of_node;
 	struct typec_capability typec_cap = { };
 	struct tps6598x *tps;
@@ -748,6 +813,7 @@ static int tps6598x_probe(struct i2c_client *client)
 			APPLE_CD_REG_INT_PLUG_EVENT;
 
 		irq_handler = cd321x_interrupt;
+		work_poll_handler = cd321x_poll_work;
 	} else {
 		/* Enable power status, data status and plug event interrupts */
 		mask1 = TPS_REG_INT_POWER_STATUS_UPDATE |
@@ -846,6 +912,16 @@ static int tps6598x_probe(struct i2c_client *client)
 					irq_handler,
 					IRQF_SHARED | IRQF_ONESHOT,
 					dev_name(&client->dev), tps);
+	if (ret == -EINVAL) {
+		dev_warn(&client->dev, "Unable to find the interrupt, switching to polling\n");
+		ret = devm_delayed_work_autocancel(tps->dev, &tps->wq_poll, work_poll_handler);
+		if (ret)
+			dev_err(&client->dev, "error while initializing workqueue\n");
+		else
+			queue_delayed_work(system_power_efficient_wq, &tps->wq_poll,
+					   msecs_to_jiffies(POLL_INTERVAL));
+	}
+
 	if (ret) {
 		tps6598x_disconnect(tps, 0);
 		typec_unregister_port(tps->port);
-- 
2.17.1