发现问题
最近画了一块f1c200s/f1c100s开发板，暂且叫它mango-pi。原理图和PCB可以参考mago-pi。
由于引脚资源有限，将按键输入引脚设计到了PA0和PA1引脚。
直接使能内核自带的gpio-key功能后，内核输出不能请求irq中断。查看gpio_keys.c源码发现在文件开始就说了这个驱动只针对能够产生中断的引脚。
后面查阅f1c200s参考手册发现PA端口居然不带GPIO中断！！！！！PD、PE、PF都有，就没有PA。所以这块板子不能使用内核自带的gpio-keys功能。
解决问题
先贴代码，占坑，后续补充。
// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for keys on GPIO lines capable of not generating interrupts.
*
* Copyright 2022 Lorenzo
* Copyright 2022, 2022 Lorenzo <liangtaozhong@gmail.com>
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/sched.h>
#include <linux/pm.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/gpio_keys.h>
#include <linux/workqueue.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/spinlock.h>
#include <dt-bindings/input/gpio-keys.h>
#include <linux/fs.h>
#include <linux/timer.h>
#include <linux/cdev.h>
#include <linux/errno.h>
#include <linux/of_gpio.h>
#include <linux/input.h>
#include <linux/semaphore.h>
#define KEYINPUT_NAME "keyinput"
#define DELAY_MS 50
static int nbuttons;
static bool rep;
struct key_dev {
dev_t devid;
struct cdev cdev;
struct class *class;
struct device *device;
struct device_node *nd;
struct timer_list timer;
struct input_dev *inputdev;
};
struct key_desc {
int gpio;
u32 code;
const char *label;
};
static struct key_desc* key = NULL;
static struct key_dev key_dev;
void timer_func(struct timer_list* timer) {
int i = 0;
struct key_desc *pkey = NULL;
pkey = key;
for (i = 0; i < nbuttons; ++i, ++pkey) {
if (gpio_get_value(pkey->gpio) == 0) {
mdelay(10);
if (gpio_get_value(pkey->gpio) == 0) {
input_report_key(key_dev.inputdev, pkey->code, 1);
input_sync(key_dev.inputdev);
}
} else {
input_report_key(key_dev.inputdev, pkey->code, 0);
input_sync(key_dev.inputdev);
}
}
mod_timer(&key_dev.timer, jiffies + msecs_to_jiffies(DELAY_MS));
}
static const struct of_device_id gpio_keys_of_match[] = {
{.compatible = "gpio-keys-scan"},
{ },
};
static int key_probe(struct platform_device *pdev) {
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct device_node *next;
int i = 0;
int ret;
nbuttons = of_get_child_count(np);
printk("having %d buttons\r\n", nbuttons);
if (!nbuttons)
return ERR_PTR(-ENODEV);
key = devm_kzalloc(dev, nbuttons * sizeof(struct key_desc),
GFP_KERNEL);
if (key == NULL) {
return -ENOMEM;
}
struct key_desc* pkey = key;
rep = of_property_read_bool(np, "autorepeat");
printk("rep : %d\n", rep);
for_each_child_of_node(np, next) {
of_property_read_string(next, "label", &(pkey->label));
of_property_read_u32(next, "linux,code", &(pkey->code));
printk("name: %s, label: %s, code: %d\n", next->name,
pkey->label, pkey->code);
pkey->gpio = of_get_named_gpio(next, "gpios", 0);
if (pkey->gpio < 0) {
printk("can't request gpio: %s\r\n", pkey->label);
return -ENODEV;
}
gpio_request(pkey->gpio, pkey->label);
gpio_direction_input(pkey->gpio);
pkey++;
}
key_dev.inputdev = input_allocate_device();
if (NULL == key_dev.inputdev)
{
printk(KERN_ERR "input_allocate_device error");
return -1;
}
key_dev.inputdev->name = KEYINPUT_NAME;
key_dev.inputdev->evbit[0] = BIT_MASK(EV_KEY);
if (rep) {
key_dev.inputdev->evbit[0] = BIT_MASK(EV_REP);
}
for (i = 0, pkey = key; i < nbuttons; ++i, ++pkey) {
input_set_capability(key_dev.inputdev, EV_KEY, pkey->code);
}
ret = input_register_device(key_dev.inputdev);
if (ret) {
printk("register input device failed\n");
for (i = 0, pkey = key; i < nbuttons; ++i, ++pkey) {
gpio_free(pkey->gpio);
}
input_unregister_device(key_dev.inputdev);
return ret;
}
/*
* Use timer to scan all buttons
*/
timer_setup(&key_dev.timer, timer_func, 0);
mod_timer(&key_dev.timer, jiffies + msecs_to_jiffies(DELAY_MS));
return 0;
}
static int key_remove(struct platform_device *dev) {
input_unregister_device(key_dev.inputdev);
input_free_device(key_dev.inputdev);
del_timer_sync(&key_dev.timer);
return 0;
}
static struct platform_driver gpio_keys_scan_driver = {
.driver = {
.name = "scan-keys",
.of_match_table = gpio_keys_of_match,
},
.probe = key_probe,
.remove = key_remove,
};
static int __init keydriver_init(void) {
return platform_driver_register(&gpio_keys_scan_driver);
}
static void __exit keydriver_exit(void) {
platform_driver_unregister(&gpio_keys_scan_driver);
}
module_init(keydriver_init);
module_exit(keydriver_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Lorenzo <liangtaozhong@gmail.com>");
MODULE_DESCRIPTION("Keyboard driver for GPIOs");
MODULE_ALIAS("platform:gpio-keys-scan");
