From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Date: Mon, 3 Apr 2017 18:18:21 +0200
Subject: [PATCH] Input: rmi4 - remove the need for artificial IRQ in case of
 HID

The IRQ from rmi4 may interfere with the one we currently use on i2c-hid.
Given that there is already a need for an external API from rmi4 to
forward the attention data, we can, in this particular case rely on a
separate workqueue to prevent cursor jumps.

Reported-by: Cameron Gutman <aicommander@gmail.com>
Reported-by: Thorsten Leemhuis <linux@leemhuis.info>
Reported-by: Jason Ekstrand <jason@jlekstrand.net>
Tested-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Lyude <lyude@redhat.com>
---
 drivers/hid/hid-rmi.c           |  64 -----------------
 drivers/input/rmi4/rmi_driver.c | 124 +++++++++++++++++++-------------
 include/linux/rmi.h             |   1 +
 3 files changed, 75 insertions(+), 114 deletions(-)

diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
index 7f41213d5ae3..86a23ede344c 100644
--- a/drivers/hid/hid-rmi.c
+++ b/drivers/hid/hid-rmi.c
@@ -322,19 +322,12 @@ static int rmi_input_event(struct hid_device *hdev, u8 *data, int size)
 {
 	struct rmi_data *hdata = hid_get_drvdata(hdev);
 	struct rmi_device *rmi_dev = hdata->xport.rmi_dev;
-	unsigned long flags;

 	if (!(test_bit(RMI_STARTED, &hdata->flags)))
 		return 0;

-	local_irq_save(flags);
-
 	rmi_set_attn_data(rmi_dev, data[1], &data[2], size - 2);

-	generic_handle_irq(hdata->rmi_irq);
-
-	local_irq_restore(flags);
-
 	return 1;
 }

@@ -591,56 +584,6 @@ static const struct rmi_transport_ops hid_rmi_ops = {
 	.reset		= rmi_hid_reset,
 };

-static void rmi_irq_teardown(void *data)
-{
-	struct rmi_data *hdata = data;
-	struct irq_domain *domain = hdata->domain;
-
-	if (!domain)
-		return;
-
-	irq_dispose_mapping(irq_find_mapping(domain, 0));
-
-	irq_domain_remove(domain);
-	hdata->domain = NULL;
-	hdata->rmi_irq = 0;
-}
-
-static int rmi_irq_map(struct irq_domain *h, unsigned int virq,
-		       irq_hw_number_t hw_irq_num)
-{
-	irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
-
-	return 0;
-}
-
-static const struct irq_domain_ops rmi_irq_ops = {
-	.map = rmi_irq_map,
-};
-
-static int rmi_setup_irq_domain(struct hid_device *hdev)
-{
-	struct rmi_data *hdata = hid_get_drvdata(hdev);
-	int ret;
-
-	hdata->domain = irq_domain_create_linear(hdev->dev.fwnode, 1,
-						 &rmi_irq_ops, hdata);
-	if (!hdata->domain)
-		return -ENOMEM;
-
-	ret = devm_add_action_or_reset(&hdev->dev, &rmi_irq_teardown, hdata);
-	if (ret)
-		return ret;
-
-	hdata->rmi_irq = irq_create_mapping(hdata->domain, 0);
-	if (hdata->rmi_irq <= 0) {
-		hid_err(hdev, "Can't allocate an IRQ\n");
-		return hdata->rmi_irq < 0 ? hdata->rmi_irq : -ENXIO;
-	}
-
-	return 0;
-}
-
 static int rmi_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
 	struct rmi_data *data = NULL;
@@ -713,18 +656,11 @@ static int rmi_probe(struct hid_device *hdev, const struct hid_device_id *id)

 	mutex_init(&data->page_mutex);

-	ret = rmi_setup_irq_domain(hdev);
-	if (ret) {
-		hid_err(hdev, "failed to allocate IRQ domain\n");
-		return ret;
-	}
-
 	if (data->device_flags & RMI_DEVICE_HAS_PHYS_BUTTONS)
 		rmi_hid_pdata.f30_data.disable = true;

 	data->xport.dev = hdev->dev.parent;
 	data->xport.pdata = rmi_hid_pdata;
-	data->xport.pdata.irq = data->rmi_irq;
 	data->xport.proto_name = "hid";
 	data->xport.ops = &hid_rmi_ops;

diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c
index 258d5fe3d395..f7298e3dc8f3 100644
--- a/drivers/input/rmi4/rmi_driver.c
+++ b/drivers/input/rmi4/rmi_driver.c
@@ -182,34 +182,47 @@ void rmi_set_attn_data(struct rmi_device *rmi_dev, unsigned long irq_status,
 	attn_data.data = fifo_data;

 	kfifo_put(&drvdata->attn_fifo, attn_data);
+
+	schedule_work(&drvdata->attn_work);
 }
 EXPORT_SYMBOL_GPL(rmi_set_attn_data);

-static irqreturn_t rmi_irq_fn(int irq, void *dev_id)
+static void attn_callback(struct work_struct *work)
 {
-	struct rmi_device *rmi_dev = dev_id;
-	struct rmi_driver_data *drvdata = dev_get_drvdata(&rmi_dev->dev);
+	struct rmi_driver_data *drvdata = container_of(work,
+							struct rmi_driver_data,
+							attn_work);
 	struct rmi4_attn_data attn_data = {0};
 	int ret, count;

 	count = kfifo_get(&drvdata->attn_fifo, &attn_data);
-	if (count) {
-		*(drvdata->irq_status) = attn_data.irq_status;
-		drvdata->attn_data = attn_data;
-	}
+	if (!count)
+		return;

-	ret = rmi_process_interrupt_requests(rmi_dev);
+	*(drvdata->irq_status) = attn_data.irq_status;
+	drvdata->attn_data = attn_data;
+
+	ret = rmi_process_interrupt_requests(drvdata->rmi_dev);
 	if (ret)
-		rmi_dbg(RMI_DEBUG_CORE, &rmi_dev->dev,
+		rmi_dbg(RMI_DEBUG_CORE, &drvdata->rmi_dev->dev,
 			"Failed to process interrupt request: %d\n", ret);

-	if (count) {
-		kfree(attn_data.data);
-		drvdata->attn_data.data = NULL;
-	}
+	kfree(attn_data.data);
+	drvdata->attn_data.data = NULL;

 	if (!kfifo_is_empty(&drvdata->attn_fifo))
-		return rmi_irq_fn(irq, dev_id);
+		schedule_work(&drvdata->attn_work);
+}
+
+static irqreturn_t rmi_irq_fn(int irq, void *dev_id)
+{
+	struct rmi_device *rmi_dev = dev_id;
+	int ret;
+
+	ret = rmi_process_interrupt_requests(rmi_dev);
+	if (ret)
+		rmi_dbg(RMI_DEBUG_CORE, &rmi_dev->dev,
+			"Failed to process interrupt request: %d\n", ret);

 	return IRQ_HANDLED;
 }
@@ -217,7 +230,6 @@ static irqreturn_t rmi_irq_fn(int irq, void *dev_id)
 static int rmi_irq_init(struct rmi_device *rmi_dev)
 {
 	struct rmi_device_platform_data *pdata = rmi_get_platform_data(rmi_dev);
-	struct rmi_driver_data *data = dev_get_drvdata(&rmi_dev->dev);
 	int irq_flags = irq_get_trigger_type(pdata->irq);
 	int ret;

@@ -235,8 +247,6 @@ static int rmi_irq_init(struct rmi_device *rmi_dev)
 		return ret;
 	}

-	data->enabled = true;
-
 	return 0;
 }

@@ -886,23 +896,27 @@ void rmi_enable_irq(struct rmi_device *rmi_dev, bool clear_wake)
 	if (data->enabled)
 		goto out;

-	enable_irq(irq);
-	data->enabled = true;
-	if (clear_wake && device_may_wakeup(rmi_dev->xport->dev)) {
-		retval = disable_irq_wake(irq);
-		if (retval)
-			dev_warn(&rmi_dev->dev,
-				 "Failed to disable irq for wake: %d\n",
-				 retval);
-	}
+	if (irq) {
+		enable_irq(irq);
+		data->enabled = true;
+		if (clear_wake && device_may_wakeup(rmi_dev->xport->dev)) {
+			retval = disable_irq_wake(irq);
+			if (retval)
+				dev_warn(&rmi_dev->dev,
+					 "Failed to disable irq for wake: %d\n",
+					 retval);
+		}

-	/*
-	 * Call rmi_process_interrupt_requests() after enabling irq,
-	 * otherwise we may lose interrupt on edge-triggered systems.
-	 */
-	irq_flags = irq_get_trigger_type(pdata->irq);
-	if (irq_flags & IRQ_TYPE_EDGE_BOTH)
-		rmi_process_interrupt_requests(rmi_dev);
+		/*
+		 * Call rmi_process_interrupt_requests() after enabling irq,
+		 * otherwise we may lose interrupt on edge-triggered systems.
+		 */
+		irq_flags = irq_get_trigger_type(pdata->irq);
+		if (irq_flags & IRQ_TYPE_EDGE_BOTH)
+			rmi_process_interrupt_requests(rmi_dev);
+	} else {
+		data->enabled = true;
+	}

 out:
 	mutex_unlock(&data->enabled_mutex);
@@ -922,20 +936,22 @@ void rmi_disable_irq(struct rmi_device *rmi_dev, bool enable_wake)
 		goto out;

 	data->enabled = false;
-	disable_irq(irq);
-	if (enable_wake && device_may_wakeup(rmi_dev->xport->dev)) {
-		retval = enable_irq_wake(irq);
-		if (retval)
-			dev_warn(&rmi_dev->dev,
-				 "Failed to enable irq for wake: %d\n",
-				 retval);
-	}
-
-	/* make sure the fifo is clean */
-	while (!kfifo_is_empty(&data->attn_fifo)) {
-		count = kfifo_get(&data->attn_fifo, &attn_data);
-		if (count)
-			kfree(attn_data.data);
+	if (irq) {
+		disable_irq(irq);
+		if (enable_wake && device_may_wakeup(rmi_dev->xport->dev)) {
+			retval = enable_irq_wake(irq);
+			if (retval)
+				dev_warn(&rmi_dev->dev,
+					 "Failed to enable irq for wake: %d\n",
+					 retval);
+		}
+	} else {
+		/* make sure the fifo is clean */
+		while (!kfifo_is_empty(&data->attn_fifo)) {
+			count = kfifo_get(&data->attn_fifo, &attn_data);
+			if (count)
+				kfree(attn_data.data);
+		}
 	}

 out:
@@ -981,6 +997,8 @@ static int rmi_driver_remove(struct device *dev)
 	irq_domain_remove(data->irqdomain);
 	data->irqdomain = NULL;

+	cancel_work_sync(&data->attn_work);
+
 	rmi_f34_remove_sysfs(rmi_dev);
 	rmi_free_function_list(rmi_dev);

@@ -1219,9 +1237,15 @@ static int rmi_driver_probe(struct device *dev)
 		}
 	}

-	retval = rmi_irq_init(rmi_dev);
-	if (retval < 0)
-		goto err_destroy_functions;
+	if (pdata->irq) {
+		retval = rmi_irq_init(rmi_dev);
+		if (retval < 0)
+			goto err_destroy_functions;
+	}
+
+	data->enabled = true;
+
+	INIT_WORK(&data->attn_work, attn_callback);

 	if (data->f01_container->dev.driver) {
 		/* Driver already bound, so enable ATTN now. */
diff --git a/include/linux/rmi.h b/include/linux/rmi.h
index 8ed37f93f3c8..d7ad35a15acb 100644
--- a/include/linux/rmi.h
+++ b/include/linux/rmi.h
@@ -363,6 +363,7 @@ struct rmi_driver_data {

 	struct rmi4_attn_data attn_data;
 	DECLARE_KFIFO(attn_fifo, struct rmi4_attn_data, 16);
+	struct work_struct attn_work;
 };

 int rmi_register_transport_device(struct rmi_transport_dev *xport);
-- 
2.26.2

