October 2017
Intermediate to advanced
586 pages
14h 8m
English
Content preview from Linux Device Drivers Development
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GPIOs mapped to IRQ
Input GPIOs can often be used as IRQ signals. Such IRQs can be edge-triggered or level-triggered. The configuration depends on your needs. The GPIO controller is responsible for providing the mapping between the GPIO and its IRQ. You can use gpio_to_irq() to map a given GPIO number to its IRQ number:
int gpio_to_irq(unsigned gpio);
The return value is the IRQ number, on which you can call request_irq() (or the threaded version request_threaded_irq()) in order to register a handler for this IRQ:
static irqreturn_t my_interrupt_handler(int irq, void *dev_id) { [...] return IRQ_HANDLED; } [...] int gpio_int = of_get_gpio(np, 0); int irq_num = gpio_to_irq(gpio_int); int error = devm_request_threaded_irq(&client->dev, irq_num, ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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