genirq/irq_sim: Simplify the API

The interrupt simulator API exposes a lot of custom data structures and
functions and doesn't reuse the interfaces already exposed by the irq
subsystem. This patch tries to address it.

We hide all the simulator-related data structures from users and instead
rely on the well-known irq domain. When creating the interrupt simulator
the user receives a pointer to a newly created irq_domain and can use it
to create mappings for simulated interrupts.

It is also possible to pass a handle to fwnode when creating the simulator
domain and retrieve it using irq_find_matching_fwnode().

The irq_sim_fire() function is dropped as well. Instead we implement the
irq_get/set_irqchip_state interface.

We modify the two modules that use the simulator at the same time as
adding these changes in order to reduce the intermediate bloat that would
result when trying to migrate the drivers in separate patches.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for IIO
Link: https://lore.kernel.org/r/20200514083901.23445-3-brgl@bgdev.pl

1 files changed, 42 insertions, 11 deletions

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index 3eb94f3740d1..bc345185db26 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -14,6 +14,7 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/irq_sim.h>
+#include <linux/irqdomain.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
@@ -48,7 +49,7 @@ struct gpio_mockup_line_status {
 struct gpio_mockup_chip {
 	struct gpio_chip gc;
 	struct gpio_mockup_line_status *lines;
-	struct irq_sim irqsim;
+	struct irq_domain *irq_sim_domain;
 	struct dentry *dbg_dir;
 	struct mutex lock;
 };
@@ -144,14 +145,12 @@ static void gpio_mockup_set_multiple(struct gpio_chip *gc,
 static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip,
 				  unsigned int offset, int value)
 {
+	int curr, irq, irq_type, ret = 0;
 	struct gpio_desc *desc;
 	struct gpio_chip *gc;
-	struct irq_sim *sim;
-	int curr, irq, irq_type;
 
 	gc = &chip->gc;
 	desc = &gc->gpiodev->descs[offset];
-	sim = &chip->irqsim;
 
 	mutex_lock(&chip->lock);
 
@@ -161,14 +160,28 @@ static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip,
 		if (curr == value)
 			goto out;
 
-		irq = irq_sim_irqnum(sim, offset);
+		irq = irq_find_mapping(chip->irq_sim_domain, offset);
+		if (!irq)
+			/*
+			 * This is fine - it just means, nobody is listening
+			 * for interrupts on this line, otherwise
+			 * irq_create_mapping() would have been called from
+			 * the to_irq() callback.
+			 */
+			goto set_value;
+
 		irq_type = irq_get_trigger_type(irq);
 
 		if ((value == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
-		    (value == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING)))
-			irq_sim_fire(sim, offset);
+		    (value == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING))) {
+			ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING,
+						    true);
+			if (ret)
+				goto out;
+		}
 	}
 
+set_value:
 	/* Change the value unless we're actively driving the line. */
 	if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
 	    !test_bit(FLAG_IS_OUT, &desc->flags))
@@ -177,7 +190,7 @@ static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip,
 out:
 	chip->lines[offset].pull = value;
 	mutex_unlock(&chip->lock);
-	return 0;
+	return ret;
 }
 
 static int gpio_mockup_set_config(struct gpio_chip *gc,
@@ -236,7 +249,7 @@ static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
 
-	return irq_sim_irqnum(&chip->irqsim, offset);
+	return irq_create_mapping(chip->irq_sim_domain, offset);
 }
 
 static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset)
@@ -389,6 +402,19 @@ static int gpio_mockup_name_lines(struct device *dev,
 	return 0;
 }
 
+static void gpio_mockup_dispose_mappings(void *data)
+{
+	struct gpio_mockup_chip *chip = data;
+	struct gpio_chip *gc = &chip->gc;
+	int i, irq;
+
+	for (i = 0; i < gc->ngpio; i++) {
+		irq = irq_find_mapping(chip->irq_sim_domain, i);
+		if (irq)
+			irq_dispose_mapping(irq);
+	}
+}
+
 static int gpio_mockup_probe(struct platform_device *pdev)
 {
 	struct gpio_mockup_chip *chip;
@@ -456,8 +482,13 @@ static int gpio_mockup_probe(struct platform_device *pdev)
 			return rv;
 	}
 
-	rv = devm_irq_sim_init(dev, &chip->irqsim, gc->ngpio);
-	if (rv < 0)
+	chip->irq_sim_domain = devm_irq_domain_create_sim(dev, NULL,
+							  gc->ngpio);
+	if (IS_ERR(chip->irq_sim_domain))
+		return PTR_ERR(chip->irq_sim_domain);
+
+	rv = devm_add_action_or_reset(dev, gpio_mockup_dispose_mappings, chip);
+	if (rv)
 		return rv;
 
 	rv = devm_gpiochip_add_data(dev, &chip->gc, chip);