74 lines
1.5 KiB
C
74 lines
1.5 KiB
C
#include <linux/gpio/consumer.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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/*
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* Last compiled with Linux 6.14.5-300.fc42.x86_64
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*/
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/* Meta Info */
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MODULE_DESCRIPTION("Demo kernel module.");
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MODULE_VERSION("0.0.1");
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MODULE_AUTHOR("Imbus");
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MODULE_LICENSE("GPL");
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/*
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* Hard coded for RPI3
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* Usually retrieved via device tree
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*/
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#define IO_LED 21
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#define IO_BUTTON 20
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#define IO_OFFSET 0
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static struct gpio_desc *led, *button;
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/**
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* @brief Called on load
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*/
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static int __init demo_mod_init(void) {
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printk(KERN_INFO "Demo module loaded successfully...");
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int status;
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led = gpio_to_desc(IO_LED + IO_OFFSET);
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if (!led) {
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printk("gpioctrl - Error getting pin 21\n");
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return -ENODEV;
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}
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button = gpio_to_desc(IO_BUTTON + IO_OFFSET);
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if (!button) {
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printk("gpioctrl - Error getting pin 20\n");
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return -ENODEV;
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}
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status = gpiod_direction_output(led, 0);
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if (status) {
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printk("gpioctrl - Error setting pin 20 to output\n");
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return status;
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}
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status = gpiod_direction_input(button);
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if (status) {
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printk("gpioctrl - Error setting pin 21 to input\n");
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return status;
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}
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gpiod_set_value(led, 1);
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printk("gpioctrl - Button is %spressed\n",
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gpiod_get_value(button) ? " " : "not ");
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return 0;
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}
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/**
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* @brief Called on unload
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*/
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static void __exit demo_mod_exit(void) {
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printk(KERN_INFO "Demo module unloaded successfully...");
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}
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module_init(demo_mod_init);
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module_exit(demo_mod_exit);
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