linux-kernel - [PATCH 2/2] gpio: sim: lock GPIOs as interrupts when they are requested

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Date: Wed, 12 Jun 2024 13:52:26 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Linus Walleij <linus.walleij@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>
Cc: linux-gpio@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH 2/2] gpio: sim: lock GPIOs as interrupts when they are requested

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

Use the notifier exposed by the interrupt simulator to be notified about
interrupts associated with simulated GPIO pins being requested or
released and lock/unlock them as interrupts accordingly.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 drivers/gpio/gpio-sim.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index 2ed5cbe7c8a8..b5526f09b22b 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -53,6 +53,7 @@ struct gpio_sim_chip {
 	struct irq_domain *irq_sim;
 	struct mutex lock;
 	const struct attribute_group **attr_groups;
+	struct notifier_block nb;
 };
 
 struct gpio_sim_attribute {
@@ -227,6 +228,24 @@ static void gpio_sim_free(struct gpio_chip *gc, unsigned int offset)
 	}
 }
 
+static int gpio_sim_irq_domain_notify(struct notifier_block *nb,
+				      unsigned long action, void *data)
+{
+	struct gpio_sim_chip *chip = container_of(nb, struct gpio_sim_chip, nb);
+	irq_hw_number_t *offset = data;
+
+	switch (action) {
+	case IRQ_SIM_DOMAIN_IRQ_REQUESTED:
+		gpiochip_lock_as_irq(&chip->gc, *offset);
+		return NOTIFY_OK;
+	case IRQ_SIM_DOMAIN_IRQ_RELEASED:
+		gpiochip_unlock_as_irq(&chip->gc, *offset);
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
 static void gpio_sim_dbg_show(struct seq_file *seq, struct gpio_chip *gc)
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
@@ -322,13 +341,15 @@ static void gpio_sim_put_device(void *data)
 	put_device(dev);
 }
 
-static void gpio_sim_dispose_mappings(void *data)
+static void gpio_sim_teardown_irq_sim(void *data)
 {
 	struct gpio_sim_chip *chip = data;
 	unsigned int i;
 
 	for (i = 0; i < chip->gc.ngpio; i++)
 		irq_dispose_mapping(irq_find_mapping(chip->irq_sim, i));
+
+	irq_sim_domain_unregister_notifier(chip->irq_sim, &chip->nb);
 }
 
 static void gpio_sim_sysfs_remove(void *data)
@@ -454,7 +475,12 @@ static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev)
 	if (IS_ERR(chip->irq_sim))
 		return PTR_ERR(chip->irq_sim);
 
-	ret = devm_add_action_or_reset(dev, gpio_sim_dispose_mappings, chip);
+	chip->nb.notifier_call = gpio_sim_irq_domain_notify;
+	ret = irq_sim_domain_register_notifier(chip->irq_sim, &chip->nb);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, gpio_sim_teardown_irq_sim, chip);
 	if (ret)
 		return ret;
 
-- 
2.40.1