[RFC PATCH v3 6/7] gpiolib: enable GPIO interrupt to wake up a system from sleep

Alex Soo
2024-05-03T11:15:13Z

Add function gpiochip_wakeup_irq_setup() to configure and enable a
GPIO pin with interrupt wakeup capability according to user-defined
wakeup-gpios property in the device tree. Interrupt generated by
toggling the logic level (rising/falling edge) on the specified
GPIO pin can wake up a system from sleep mode.

Signed-off-by: Alex Soo <yuklin.soo@starfivetech.com>
---
drivers/gpio/gpiolib.c | 87 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 87 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 94903fc1c145..92cfbc34abb0 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -19,6 +19,7 @@
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pinctrl/consumer.h>
+#include <linux/pm_wakeirq.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
@@ -96,6 +97,7 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gc);
static int gpiochip_irqchip_init_hw(struct gpio_chip *gc);
static int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gc);
static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gc);
+static int gpiochip_wakeup_irq_setup(struct gpio_chip *gc);

static bool gpiolib_initialized;

@@ -1045,8 +1047,15 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
if (ret)
goto err_remove_irqchip;
}
+
+ ret = gpiochip_wakeup_irq_setup(gc);
+ if (ret)
+ goto err_remove_device;
+
return 0;

+err_remove_device:
+ gcdev_unregister(gdev);
err_remove_irqchip:
gpiochip_irqchip_remove(gc);
err_remove_irqchip_mask:
@@ -1874,6 +1883,84 @@ static int gpiochip_irqchip_add_allocated_domain(struct gpio_chip *gc,
return 0;
}

+static irqreturn_t gpio_wake_irq_handler(int irq, void *data)
+{
+ struct irq_data *irq_data = data;
+
+ if (!irq_data || irq != irq_data->irq)
+ return IRQ_NONE;
+
+ return IRQ_HANDLED;
+}
+
+static int gpiochip_wakeup_irq_setup(struct gpio_chip *gc)
+{
+ struct device *dev = gc->parent;
+ struct gpio_irq_chip *girq = &gc->irq;
+ struct gpio_desc *wakeup_gpiod;
+ struct irq_desc *wakeup_irqd;
+ struct irq_domain *irq_domain;
+ struct irq_data *irq_data;
+ unsigned int offset;
+ int wakeup_irq;
+ int ret;
+
+ if (!(device_property_read_bool(dev, "wakeup-source")))
+ return 0;
+
+ irq_domain = girq->domain;
+
+ if (!irq_domain) {
+ dev_err(dev, "Couldn't allocate IRQ domain\n");
+ return -ENXIO;
+ }
+
+ wakeup_gpiod = devm_gpiod_get_optional(dev, "wakeup", GPIOD_IN);
+
+ if (IS_ERR(wakeup_gpiod)) {
+ dev_err(dev, "invalid wakeup gpio: %lu\n", PTR_ERR(wakeup_gpiod));
+ return PTR_ERR(wakeup_gpiod);
+ }
+ if (!wakeup_gpiod) {
+ dev_dbg(dev, "property wakeup-gpios is not defined\n");
+ return 0;
+ }
+
+ offset = gpio_chip_hwgpio(wakeup_gpiod);
+ wakeup_irq = gpiod_to_irq(wakeup_gpiod);
+ if (wakeup_irq < 0) {
+ dev_err(dev, "failed to convert wakeup GPIO to IRQ\n");
+ return wakeup_irq;
+ }
+ irq_domain->ops->map(irq_domain, wakeup_irq, offset);
+ wakeup_irqd = irq_to_desc(wakeup_irq);
+ irq_data = irq_get_irq_data(wakeup_irq);
+ girq->handler = handle_edge_irq;
+
+ if (!(wakeup_irqd->status_use_accessors & IRQ_NOREQUEST)) {
+ device_init_wakeup(dev, 1);
+ ret = devm_request_threaded_irq(dev, wakeup_irq, NULL,
+ gpio_wake_irq_handler,
+ IRQF_TRIGGER_FALLING |
+ IRQF_TRIGGER_RISING |
+ IRQF_ONESHOT |
+ IRQF_SHARED,
+ "pm-wakeup-gpio", irq_data);
+ if (ret) {
+ dev_err(dev, "unable to request wakeup IRQ: %d\n", ret);
+ return ret;
+ }
+ }
+
+ ret = dev_pm_set_wake_irq(dev, wakeup_irq);
+ if (ret) {
+ dev_err(dev, "failed to enable gpio irq wake\n");
+ return ret;
+ }
+
+ return 0;
+}
+
/**
* gpiochip_add_irqchip() - adds an IRQ chip to a GPIO chip
* @gc: the GPIO chip to add the IRQ chip to
--
2.25.1