使用“Linux自带的按键驱动程序”测试“按键输入”，熟悉图形化配置。
Linux内核定时器的“系统节拍率”默认选择100Hz。
1 、通过“linux内核图形化配置界面”令“CONFIG_LEDS_GPIO=y”
1)、打开终端，输入“cd linux/atk-mp1/linux/my_linux/linux-5.4.31/回车”，切换到“linux/atk-mp1/linux/my_linux/linux-5.4.31/”目录；输入“make menuconfig回车”，打开linux内核图形化配置界面：
2)、移动“向下光标键”，至“Device Drivers”
3)、输入“回车键”，得到下图：
4)、移动“向下光标键”，至“Input device support”
5)、输入“回车”，得到下图：
6)、按“Y”，移动“向下光标键”至“Keyboards”，得到下图：
7)、先按“Y”键，再按“回车键”，得到下图：
8)、移到“向下光标键”至“GPIO Buttons”
9)、按下“Y”键，使此选项前面变为“<*>”，即选中Linux内核自带的KEY驱动。然后按“TAB键”至“Exit”,再按“回车”退出，直至到达下面这个界面：
10)、按“TAB键”至“Save”,按下“回车”，得到下面的界面。
11)、输入“./arch/arm/configs/stm32mp1_atk_defconfig”，移动“向下光标键”至“Ok”，得到下图：
12)、按“回车”,保存完成。得到下面的界面。
13)、按“回车”，退出。
14)、按两次“ESC键”，得到下图：
2、打开“./arch/arm/configs/stm32mp1_atk_defconfig”，查看“CONFIG_KEYBOARD_GPIO=y”。
1)、输入“vi ./arch/arm/configs/stm32mp1_atk_defconfig回车”，打开“stm32mp1_atk_defconfig”文件。
2)、按“ESC键”，按下“/”，后，输入“CONFIG_KEYBOARD_GPIO回车”，搜索“CONFIG_LEDS_GPIO”，见下图：
3)、发现“CONFIG_KEYBOARD_GPIO=y”，按“ESC键”，按“:q!回车”，不保存退出；
3、修改设备树
1)、打开虚拟机上“VSCode”，点击“文件”，点击“打开文件夹”，点击“zgq”，点击“linux”，点击“atk-mp1”，点击“linux”，点击“my_linux”，点击“linux-5.4.31”，点击“确定”，点击“stm32mp157d-atk.dts”。
2)、先添加一个头文件“dt-bindings/input/input.h”此文件就是“linux,code”属性的按键宏定义。
添加“#include "dt-bindings/input/input.h"”，见下图：
添加内容如下：
gpio-keys {
compatible = "gpio-keys";/*设置属性compatible的值为"gpio-keys"*/
pinctrl-names = "default";
pinctrl-0 = <&key_pins_a>;
/*“&gpiog”表示key-gpio引脚所使用的IO属于GPIOG组*/
/*“3’表示GPIOG组的第3号IO，即PG3引脚*/
/*“GPIO_ACTIVE_LOW”表示低电平有效,“GPIO_PULL_UP”表示上拉*/
autorepeat;/*表示按键支持连按*/
key0 {
label = "GPIO Key L";
linux,code = <KEY_L>;
gpios = <&gpiog 3 GPIO_ACTIVE_LOW>;
/*“&gpiog”表示gpios引脚所使用的IO属于GPIOG组*/
/*“3’表示GPIOG组的第3号IO，即PG3引脚*/
/*“GPIO_ACTIVE_LOW”表示低电平有效,“GPIO_PULL_UP”表示上拉*/
};
key1 {
label = "GPIO Key S";
linux,code = <KEY_S>;
gpios = <&gpioh 7 GPIO_ACTIVE_LOW>;
/*“&gpioh”表示gpios引脚所使用的IO属于GPIOH组*/
/*“7’表示GPIOH组的第7号IO，即PH7引脚*/
/*“GPIO_ACTIVE_LOW”表示低电平有效,“GPIO_PULL_UP”表示上拉*/
};
wkup {
label = "GPIO Key Enter";
linux,code = <KEY_ENTER>;
gpios = <&gpioa 0 GPIO_ACTIVE_HIGH>;
/*“&gpioa”表示gpios引脚所使用的IO属于GPIOA组*/
/*“0’表示GPIOA组的第0号IO，即PA0引脚*/
/*“GPIO_ACTIVE_LOW”表示低电平有效,“GPIO_PULL_UP”表示上拉*/
gpio-key,wakeup;
};
};
4、编译设备树
①在VSCode终端，输入“make dtbs回车”，执行编译设备树
②输入“ls arch/arm/boot/uImage -l”
查看是否生成了新的“uImage”文件
③输入“ls arch/arm/boot/dts/stm32mp157d-atk.dtb -l”
查看是否生成了新的“stm32mp157d-atk.dtb”文件
4)、拷贝输出的文件：
①输入“cp arch/arm/boot/uImage /home/zgq/linux/atk-mp1/linux/bootfs/ -f回车”，执行文件拷贝，准备烧录到EMMC；
②输入“cp arch/arm/boot/dts/stm32mp157d-atk.dtb /home/zgq/linux/atk-mp1/linux/bootfs/ -f回车”，执行文件拷贝，准备烧录到EMMC
③输入“cp arch/arm/boot/uImage /home/zgq/linux/tftpboot/ -f回车”，执行文件拷贝，准备从tftp下载；
④输入“cp arch/arm/boot/dts/stm32mp157d-atk.dtb /home/zgq/linux/tftpboot/ -f回车”，执行文件拷贝，准备从tftp下载；
⑤输入“ls -l /home/zgq/linux/atk-mp1/linux/bootfs/回车”，查看“/home/zgq/linux/atk-mp1/linux/bootfs/”目录下的所有文件和文件夹
⑥输入“ls -l /home/zgq/linux/tftpboot/回车”，查看“/home/zgq/linux/tftpboot/”目录下的所有文件和文件夹
⑦输入“chmod 777 /home/zgq/linux/tftpboot/stm32mp157d-atk.dtb回车”
给“stm32mp157d-atk.dtb”文件赋予可执行权限
⑧输入“chmod 777 /home/zgq/linux/tftpboot/uImage回车” ,给“uImage”文件赋予可执行权限
⑨输入“ls /home/zgq/linux/tftpboot/ -l回车”，查看“/home/zgq/linux/tftpboot/”目录下的所有文件和文件夹
5、测试
1)、给开发板上电，用新的umage和stm32mpl57d-atk.dtb启动开发板。
2)、输入“root回车”。
3)、输入“cd /lib/modules/5.4.31/回车”
在nfs挂载中，切换到“/lib/modules/5.4.31/”目录，
注意：“lib/modules/5.4.31/”在虚拟机中是位于“/home/zgq/linux/nfs/rootfs/”目录下，但在开发板中，却是位于根目录中。
4)、输入“ls /dev/input/ -l回车”，发现有“/dev/input”这个目录。
5)、输入“hexdump /dev/input/event0回车”,执行读按键KEY0,KEY1和wkup
观察串口输出。
6、了解“gpio_keys.c”
Linux内核自带的KEY驱动文件为drivers/input/keyboard/gpio_keys.c，gpio_keys.c采用了 platfomm驱动框架，在KEY驱动上使用了input子系统实现。
gpio_keys.c如下：
#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/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>
struct gpio_button_data {
const struct gpio_keys_button *button;
struct gpio_desc *gpiod;
unsigned short *code;
struct timer_list release_timer;
unsigned int release_delay; /* in msecs, for IRQ-only buttons */
struct delayed_work work;
unsigned int software_debounce; /* in msecs, for GPIO-driven buttons */
unsigned int irq;
unsigned int wakeup_trigger_type;
spinlock_t lock;
bool disabled;
bool key_pressed;
bool suspended;
};
struct gpio_keys_drvdata {
const struct gpio_keys_platform_data *pdata;
struct mutex disable_lock;
unsigned short *keymap;
struct gpio_button_data data[0];
};
/*
* SYSFS interface for enabling/disabling keys and switches:
*
* There are 4 attributes under /sys/devices/platform/gpio-keys/
* keys [ro] - bitmap of keys (EV_KEY) which can be disabled
* switches [ro] - bitmap of switches (EV_SW) which can be disabled
* disabled_keys [rw] - bitmap of keys currently disabled
* disabled_switches [rw] - bitmap of switches currently disabled
* Userland can change these values and hence disable event generation
* for each key (or switch). Disabling a key means its interrupt line
* is disabled.
*
* For example, if we have following switches set up as gpio-keys:
* SW_DOCK = 5
* SW_CAMERA_LENS_COVER = 9
* SW_KEYPAD_SLIDE = 10
* SW_FRONT_PROXIMITY = 11
* This is read from switches:
* 11-9,5
* Next we want to disable proximity (11) and dock (5), we write:
* 11,5
* to file disabled_switches. Now proximity and dock IRQs are disabled.
* This can be verified by reading the file disabled_switches:
* 11,5
* If we now want to enable proximity (11) switch we write:
* 5
* to disabled_switches.
*
* We can disable only those keys which don't allow sharing the irq.
*/
/**
* get_n_events_by_type() - returns maximum number of events per @type
* @type: type of button (%EV_KEY, %EV_SW)
*
* Return value of this function can be used to allocate bitmap
* large enough to hold all bits for given type.
*/
static int get_n_events_by_type(int type)
{
BUG_ON(type != EV_SW && type != EV_KEY);
return (type == EV_KEY) ? KEY_CNT : SW_CNT;
}
/**
* get_bm_events_by_type() - returns bitmap of supported events per @type
* @input: input device from which bitmap is retrieved
* @type: type of button (%EV_KEY, %EV_SW)
*
* Return value of this function can be used to allocate bitmap
* large enough to hold all bits for given type.
*/
static const unsigned long *get_bm_events_by_type(struct input_dev *dev, int type)
{
BUG_ON(type != EV_SW && type != EV_KEY);
return (type == EV_KEY) ? dev->keybit : dev->swbit;
}
/**
* gpio_keys_disable_button() - disables given GPIO button
* @bdata: button data for button to be disabled
*
* Disables button pointed by @bdata. This is done by masking
* IRQ line. After this function is called, button won't generate
* input events anymore. Note that one can only disable buttons
* that don't share IRQs.
*
* Make sure that @bdata->disable_lock is locked when entering
* this function to avoid races when concurrent threads are
* disabling buttons at the same time.
*/
static void gpio_keys_disable_button(struct gpio_button_data *bdata)
{
if (!bdata->disabled) {
/*Disable IRQ and associated timer/work structure.*/
disable_irq(bdata->irq);
if (bdata->gpiod) cancel_delayed_work_sync(&bdata->work);
else del_timer_sync(&bdata->release_timer); /* 删除timer */
bdata->disabled = true;
}
}
/**
* gpio_keys_enable_button() - enables given GPIO button
* @bdata: button data for button to be disabled
*
* Enables given button pointed by @bdata.
*
* Make sure that @bdata->disable_lock is locked when entering
* this function to avoid races with concurrent threads trying
* to enable the same button at the same time.
*/
static void gpio_keys_enable_button(struct gpio_button_data *bdata)
{
if (bdata->disabled)
{
enable_irq(bdata->irq);
bdata->disabled = false;
}
}
/**
* gpio_keys_attr_show_helper() - fill in stringified bitmap of buttons
* @ddata: pointer to drvdata
* @buf: buffer where stringified bitmap is written
* @type: button type (%EV_KEY, %EV_SW)
* @only_disabled: does caller want only those buttons that are
* currently disabled or all buttons that can be
* disabled
*
* This function writes buttons that can be disabled to @buf. If
* @only_disabled is true, then @buf contains only those buttons
* that are currently disabled. Returns 0 on success or negative
* errno on failure.
*/
static ssize_t gpio_keys_attr_show_helper(struct gpio_keys_drvdata *ddata,
char *buf, unsigned int type,
bool only_disabled)
{
int n_events = get_n_events_by_type(type);
unsigned long *bits;
ssize_t ret;
int i;
bits = bitmap_zalloc(n_events, GFP_KERNEL);
if (!bits)
return -ENOMEM;
for (i = 0; i < ddata->pdata->nbuttons; i++) {
struct gpio_button_data *bdata = &ddata->data[i];
if (bdata->button->type != type)
continue;
if (only_disabled && !bdata->disabled)
continue;
__set_bit(*bdata->code, bits);
}
ret = scnprintf(buf, PAGE_SIZE - 1, "%*pbl", n_events, bits);
buf[ret++] = '\n';
buf[ret] = '\0';
bitmap_free(bits);
return ret;
}
/**
* gpio_keys_attr_store_helper() - enable/disable buttons based on given bitmap
* @ddata: pointer to drvdata
* @buf: buffer from userspace that contains stringified bitmap
* @type: button type (%EV_KEY, %EV_SW)
*
* This function parses stringified bitmap from @buf and disables/enables
* GPIO buttons accordingly. Returns 0 on success and negative error
* on failure.
*/
static ssize_t gpio_keys_attr_store_helper(struct gpio_keys_drvdata *ddata,
const char *buf, unsigned int type)
{
int n_events = get_n_events_by_type(type);
const unsigned long *bitmap = get_bm_events_by_type(ddata->input, type);
unsigned long *bits;
ssize_t error;
int i;
bits = bitmap_zalloc(n_events, GFP_KERNEL);
if (!bits) return -ENOMEM;
error = bitmap_parselist(buf, bits, n_events);
if (error) goto out;
/* First validate */
if (!bitmap_subset(bits, bitmap, n_events)) {
error = -EINVAL;
goto out;
}
for (i = 0; i < ddata->pdata->nbuttons; i++)
{
struct gpio_button_data *bdata = &ddata->data[i];
if (bdata->button->type != type) continue;
if (test_bit(*bdata->code, bits) && !bdata->button->can_disable)
{
error = -EINVAL;
goto out;
}
}
mutex_lock(&ddata->disable_lock);
for (i = 0; i < ddata->pdata->nbuttons; i++)
{
struct gpio_button_data *bdata = &ddata->data[i];
if (bdata->button->type != type) continue;
if (test_bit(*bdata->code, bits)) gpio_keys_disable_button(bdata);
else gpio_keys_enable_button(bdata);
}
mutex_unlock(&ddata->disable_lock);
out:
bitmap_free(bits);
return error;
}
#define ATTR_SHOW_FN(name, type, only_disabled) \
static ssize_t gpio_keys_show_##name(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct platform_device *pdev = to_platform_device(dev); \
struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
\
return gpio_keys_attr_show_helper(ddata, buf,type, only_disabled); \
}
ATTR_SHOW_FN(keys, EV_KEY, false);
ATTR_SHOW_FN(switches, EV_SW, false);
ATTR_SHOW_FN(disabled_keys, EV_KEY, true);
ATTR_SHOW_FN(disabled_switches, EV_SW, true);
/*
* ATTRIBUTES:
*
* /sys/devices/platform/gpio-keys/keys [ro]
* /sys/devices/platform/gpio-keys/switches [ro]
*/
static DEVICE_ATTR(keys, S_IRUGO, gpio_keys_show_keys, NULL);
static DEVICE_ATTR(switches, S_IRUGO, gpio_keys_show_switches, NULL);
#define ATTR_STORE_FN(name, type) \
static ssize_t gpio_keys_store_##name(struct device *dev, \
struct device_attribute *attr, \
const char *buf, \
size_t count) \
{ \
struct platform_device *pdev = to_platform_device(dev); \
struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
ssize_t error; \
\
error = gpio_keys_attr_store_helper(ddata, buf, type); \
if (error) \
return error; \
\
return count; \
}
ATTR_STORE_FN(disabled_keys, EV_KEY);
ATTR_STORE_FN(disabled_switches, EV_SW);
/*
* ATTRIBUTES:
*
* /sys/devices/platform/gpio-keys/disabled_keys [rw]
* /sys/devices/platform/gpio-keys/disables_switches [rw]
*/
static DEVICE_ATTR(disabled_keys, S_IWUSR | S_IRUGO,
gpio_keys_show_disabled_keys,
gpio_keys_store_disabled_keys);
static DEVICE_ATTR(disabled_switches, S_IWUSR | S_IRUGO,
gpio_keys_show_disabled_switches,
gpio_keys_store_disabled_switches);
static struct attribute *gpio_keys_attrs[] = {
&dev_attr_keys.attr,
&dev_attr_switches.attr,
&dev_attr_disabled_keys.attr,
&dev_attr_disabled_switches.attr,
NULL,
};
ATTRIBUTE_GROUPS(gpio_keys);
static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
{
const struct gpio_keys_button *button = bdata->button;
struct input_dev *input = bdata->input;
unsigned int type = button->type ?: EV_KEY;
int state;
state = gpiod_get_value_cansleep(bdata->gpiod);
if (state < 0) {
dev_err(input->dev.parent,
"failed to get gpio state: %d\n", state);
return;
}
if (type == EV_ABS)
{
if (state) input_event(input, type, button->code, button->value);
}
else { input_event(input, type, *bdata->code, state);}
}
static void gpio_keys_gpio_work_func(struct work_struct *work)
{
struct gpio_button_data *bdata = container_of(work, struct gpio_button_data, work.work);
gpio_keys_gpio_report_event(bdata);
if (bdata->button->wakeup) pm_relax(bdata->input->dev.parent);
}
static irqreturn_t gpio_keys_gpio_isr(int irq, void *dev_id)
{
struct gpio_button_data *bdata = dev_id;
BUG_ON(irq != bdata->irq);
if (bdata->button->wakeup)
{
const struct gpio_keys_button *button = bdata->button;
pm_stay_awake(bdata->input->dev.parent);
if (bdata->suspended && (button->type == 0 || button->type == EV_KEY)) {
/*
* Simulate wakeup key press in case the key has
* already released by the time we got interrupt
* handler to run.
*/
input_report_key(bdata->input, button->code, 1);
}
}
mod_delayed_work(system_wq,&bdata->work,msecs_to_jiffies(bdata->software_debounce);
return IRQ_HANDLED;
}
static void gpio_keys_irq_timer(struct timer_list *t)
{
struct gpio_button_data *bdata = from_timer(bdata, t, release_timer);
struct input_dev *input = bdata->input;
unsigned long flags;
spin_lock_irqsave(&bdata->lock, flags);
if (bdata->key_pressed) {
input_event(input, EV_KEY, *bdata->code, 0);
bdata->key_pressed = false;
}
spin_unlock_irqrestore(&bdata->lock, flags);
}
static irqreturn_t gpio_keys_irq_isr(int irq, void *dev_id)
{
struct gpio_button_data *bdata = dev_id;
struct input_dev *input = bdata->input;
unsigned long flags;
BUG_ON(irq != bdata->irq);
spin_lock_irqsave(&bdata->lock, flags);
if (!bdata->key_pressed)
{
if (bdata->button->wakeup) pm_wakeup_event(bdata->input->dev.parent, 0);
input_event(input, EV_KEY, *bdata->code, 1);
if (!bdata->release_delay)
{
input_event(input, EV_KEY, *bdata->code, 0);
goto out;
}
bdata->key_pressed = true;
}
if (bdata->release_delay) mod_timer(&bdata->release_timer,jiffies + msecs_to_jiffies(bdata->release_delay));
out:
spin_unlock_irqrestore(&bdata->lock, flags);
return IRQ_HANDLED;
}
static void gpio_keys_quiesce_key(void *data)
{
struct gpio_button_data *bdata = data;
if (bdata->gpiod) cancel_delayed_work_sync(&bdata->work);
else del_timer_sync(&bdata->release_timer); /* 删除timer */
}
static int gpio_keys_setup_key(struct platform_device *pdev,
struct gpio_keys_drvdata *ddata,
const struct gpio_keys_button *button,
int idx,
struct fwnode_handle *child)
{
const char *desc = button->desc ? button->desc : "gpio_keys";
struct device *dev = &pdev->dev;
struct gpio_button_data *bdata = &ddata->data[idx];
irq_handler_t isr;
unsigned long irqflags;
int irq;
int error;
bdata->button = button;
spin_lock_init(&bdata->lock);
if (child)
{
bdata->gpiod = devm_fwnode_get_gpiod_from_child(dev, NULL,
child,
GPIOD_IN,
desc);
if (IS_ERR(bdata->gpiod)) {
error = PTR_ERR(bdata->gpiod);
if (error == -ENOENT) {
/*
* GPIO is optional, we may be dealing with
* purely interrupt-driven setup.
*/
bdata->gpiod = NULL;
} else {
if (error != -EPROBE_DEFER)
dev_err(dev, "failed to get gpio: %d\n",
error);
return error;
}
}
} else if (gpio_is_valid(button->gpio)) {
/*
* Legacy GPIO number, so request the GPIO here and
* convert it to descriptor.
*/
unsigned flags = GPIOF_IN;
if (button->active_low)
flags |= GPIOF_ACTIVE_LOW;
error = devm_gpio_request_one(dev, button->gpio, flags, desc);
if (error < 0) {
dev_err(dev, "Failed to request GPIO %d, error %d\n",
button->gpio, error);
return error;
}
bdata->gpiod = gpio_to_desc(button->gpio);
if (!bdata->gpiod)
return -EINVAL;
}
if (bdata->gpiod) {
bool active_low = gpiod_is_active_low(bdata->gpiod);
if (button->debounce_interval) {
error = gpiod_set_debounce(bdata->gpiod,
button->debounce_interval * 1000);
/* use timer if gpiolib doesn't provide debounce */
if (error < 0)
bdata->software_debounce =
button->debounce_interval;
}
if (button->irq) {
bdata->irq = button->irq;
} else {
irq = gpiod_to_irq(bdata->gpiod);
if (irq < 0) {
error = irq;
dev_err(dev,
"Unable to get irq number for GPIO %d, error %d\n",
button->gpio, error);
return error;
}
bdata->irq = irq;
}
INIT_DELAYED_WORK(&bdata->work, gpio_keys_gpio_work_func);
isr = gpio_keys_gpio_isr;
irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
switch (button->wakeup_event_action) {
case EV_ACT_ASSERTED:
bdata->wakeup_trigger_type = active_low ?
IRQ_TYPE_EDGE_FALLING : IRQ_TYPE_EDGE_RISING;
break;
case EV_ACT_DEASSERTED:
bdata->wakeup_trigger_type = active_low ?
IRQ_TYPE_EDGE_RISING : IRQ_TYPE_EDGE_FALLING;
break;
case EV_ACT_ANY:
/* fall through */
default:
/*
* For other cases, we are OK letting suspend/resume
* not reconfigure the trigger type.
*/
break;
}
} else {
if (!button->irq) {
dev_err(dev, "Found button without gpio or irq\n");
return -EINVAL;
}
bdata->irq = button->irq;
if (button->type && button->type != EV_KEY) {
dev_err(dev, "Only EV_KEY allowed for IRQ buttons.\n");
return -EINVAL;
}
bdata->release_delay = button->debounce_interval;
timer_setup(&bdata->release_timer, gpio_keys_irq_timer, 0);
isr = gpio_keys_irq_isr;
irqflags = 0;
/*
* For IRQ buttons, there is no interrupt for release.
* So we don't need to reconfigure the trigger type for wakeup.
*/
}
bdata->code = &ddata->keymap[idx];
*bdata->code = button->code;
input_set_capability(input, button->type ?: EV_KEY, *bdata->code);
/*
* Install custom action to cancel release timer and
* workqueue item.
*/
error = devm_add_action(dev, gpio_keys_quiesce_key, bdata);
if (error) {
dev_err(dev, "failed to register quiesce action, error: %d\n",
error);
return error;
}
/*
* If platform has specified that the button can be disabled,
* we don't want it to share the interrupt line.
*/
if (!button->can_disable)
irqflags |= IRQF_SHARED;
error = devm_request_any_context_irq(dev, bdata->irq, isr, irqflags,
desc, bdata);
if (error < 0) {
dev_err(dev, "Unable to claim irq %d; error %d\n",
bdata->irq, error);
return error;
}
return 0;
}
static void gpio_keys_report_state(struct gpio_keys_drvdata *ddata)
{
struct input_dev *input = ddata->input;
int i;
for (i = 0; i < ddata->pdata->nbuttons; i++) {
struct gpio_button_data *bdata = &ddata->data[i];
if (bdata->gpiod) gpio_keys_gpio_report_event(bdata);
}
}
static int gpio_keys_open(struct input_dev *input)
{
struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
const struct gpio_keys_platform_data *pdata = ddata->pdata;
int error;
if (pdata->enable)
{
error = pdata->enable(input->dev.parent);
if (error) return error;
}
/* Report current state of buttons that are connected to GPIOs */
gpio_keys_report_state(ddata);
return 0;
}
static void gpio_keys_close(struct input_dev *input)
{
struct gpio_keys_drvdata *ddata = input_get_drvdata(input);
const struct gpio_keys_platform_data *pdata = ddata->pdata;
if (pdata->disable) pdata->disable(input->dev.parent);
}
/*
* Handlers for alternative sources of platform_data
*/
/*
* Translate properties into platform_data
*/
static struct gpio_keys_platform_data *gpio_keys_get_devtree_pdata(struct device *dev)
{
struct gpio_keys_platform_data *pdata;
struct gpio_keys_button *button;
struct fwnode_handle *child;
int nbuttons;
nbuttons = device_get_child_node_count(dev);
if (nbuttons == 0) return ERR_PTR(-ENODEV);
pdata = devm_kzalloc(dev,
sizeof(*pdata) + nbuttons * sizeof(*button),
GFP_KERNEL);
if (!pdata) return ERR_PTR(-ENOMEM);
button = (struct gpio_keys_button *)(pdata + 1);
pdata->buttons = button;
pdata->nbuttons = nbuttons;
pdata->rep = device_property_read_bool(dev, "autorepeat");
device_property_read_string(dev, "label", &pdata->name);
device_for_each_child_node(dev, child)
{
if (is_of_node(child))
button->irq = irq_of_parse_and_map(to_of_node(child), 0);
if (fwnode_property_read_u32(child, "linux,code",&button->code))
{
dev_err(dev, "Button without keycode\n");
fwnode_handle_put(child);
return ERR_PTR(-EINVAL);
}
fwnode_property_read_string(child, "label", &button->desc);
if (fwnode_property_read_u32(child, "linux,input-type",&button->type))
button->type = EV_KEY;
button->wakeup =
fwnode_property_read_bool(child, "wakeup-source") ||
/* legacy name */
fwnode_property_read_bool(child, "gpio-key,wakeup");
fwnode_property_read_u32(child, "wakeup-event-action",
&button->wakeup_event_action);
button->can_disable =
fwnode_property_read_bool(child, "linux,can-disable");
if (fwnode_property_read_u32(child, "debounce-interval",
&button->debounce_interval))
button->debounce_interval = 5;
button++;
}
return pdata;
}
static const struct of_device_id gpio_keys_of_match[] = {
{ .compatible = "gpio-keys", },
{ },
};
MODULE_DEVICE_TABLE(of, gpio_keys_of_match);
static int gpio_keys_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
struct fwnode_handle *child = NULL;
struct gpio_keys_drvdata *ddata;
int i, error;
int wakeup = 0;
if (!pdata) {
pdata = gpio_keys_get_devtree_pdata(dev);
if (IS_ERR(pdata)) return PTR_ERR(pdata);
}
ddata = devm_kzalloc(dev, struct_size(ddata, data, pdata->nbuttons),GFP_KERNEL);
if (!ddata) {
dev_err(dev, "failed to allocate state\n");
return -ENOMEM;
}
ddata->keymap = devm_kcalloc(dev,pdata->nbuttons, sizeof(ddata->keymap[0]),
GFP_KERNEL);
if (!ddata->keymap) return -ENOMEM;
input = devm_input_allocate_device(dev);
if (!input) {
dev_err(dev, "failed to allocate input device\n");
return -ENOMEM;
}
ddata->pdata = pdata;
mutex_init(&ddata->disable_lock);
platform_set_drvdata(pdev, ddata);
input_set_drvdata(input, ddata);
input->name = pdata->name ? : pdev->name;
input->phys = "gpio-keys/input0";
input->dev.parent = dev;
input->open = gpio_keys_open;
input->close = gpio_keys_close;
input->id.bustype = BUS_HOST;
input->id.vendor = 0x0001;
input->id.product = 0x0001;
input->id.version = 0x0100;
input->keycode = ddata->keymap;
input->keycodesize = sizeof(ddata->keymap[0]);
input->keycodemax = pdata->nbuttons;
/* Enable auto repeat feature of Linux input subsystem */
if (pdata->rep)
__set_bit(EV_REP, input->evbit);
for (i = 0; i < pdata->nbuttons; i++) {
const struct gpio_keys_button *button = &pdata->buttons[i];
if (!dev_get_platdata(dev)) {
child = device_get_next_child_node(dev, child);
if (!child) {
dev_err(dev,
"missing child device node for entry %d\n",
i);
return -EINVAL;
}
}
error = gpio_keys_setup_key(pdev, input, ddata,
button, i, child);
if (error) {
fwnode_handle_put(child);
return error;
}
if (button->wakeup) wakeup = 1;
}
fwnode_handle_put(child);
error = input_register_device(input);
if (error) {
dev_err(dev, "Unable to register input device, error: %d\n",
error);
return error;
}
device_init_wakeup(dev, wakeup);
return 0;
}
static int __maybe_unused
gpio_keys_button_enable_wakeup(struct gpio_button_data *bdata)
{
int error;
error = enable_irq_wake(bdata->irq);
if (error) {
dev_err(bdata->input->dev.parent,
"failed to configure IRQ %d as wakeup source: %d\n",
bdata->irq, error);
return error;
}
if (bdata->wakeup_trigger_type) {
error = irq_set_irq_type(bdata->irq,
bdata->wakeup_trigger_type);
if (error) {
dev_err(bdata->input->dev.parent,
"failed to set wakeup trigger %08x for IRQ %d: %d\n",
bdata->wakeup_trigger_type, bdata->irq, error);
disable_irq_wake(bdata->irq);
return error;
}
}
return 0;
}
static void __maybe_unused
gpio_keys_button_disable_wakeup(struct gpio_button_data *bdata)
{
int error;
/*
* The trigger type is always both edges for gpio-based keys and we do
* not support changing wakeup trigger for interrupt-based keys.
*/
if (bdata->wakeup_trigger_type) {
error = irq_set_irq_type(bdata->irq, IRQ_TYPE_EDGE_BOTH);
if (error)
dev_warn(bdata->input->dev.parent,
"failed to restore interrupt trigger for IRQ %d: %d\n",
bdata->irq, error);
}
error = disable_irq_wake(bdata->irq);
if (error)
dev_warn(bdata->input->dev.parent,
"failed to disable IRQ %d as wake source: %d\n",
bdata->irq, error);
}
static int __maybe_unused
gpio_keys_enable_wakeup(struct gpio_keys_drvdata *ddata)
{
struct gpio_button_data *bdata;
int error;
int i;
for (i = 0; i < ddata->pdata->nbuttons; i++) {
bdata = &ddata->data[i];
if (bdata->button->wakeup) {
error = gpio_keys_button_enable_wakeup(bdata);
if (error)
goto err_out;
}
bdata->suspended = true;
}
return 0;
err_out:
while (i--) {
bdata = &ddata->data[i];
if (bdata->button->wakeup)
gpio_keys_button_disable_wakeup(bdata);
bdata->suspended = false;
}
return error;
}
static void __maybe_unused
gpio_keys_disable_wakeup(struct gpio_keys_drvdata *ddata)
{
struct gpio_button_data *bdata;
int i;
for (i = 0; i < ddata->pdata->nbuttons; i++) {
bdata = &ddata->data[i];
bdata->suspended = false;
if (irqd_is_wakeup_set(irq_get_irq_data(bdata->irq)))
gpio_keys_button_disable_wakeup(bdata);
}
}
static int __maybe_unused gpio_keys_suspend(struct device *dev)
{
struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);
struct input_dev *input = ddata->input;
int error;
if (device_may_wakeup(dev))
{
error = gpio_keys_enable_wakeup(ddata);
if (error) return error;
}
else {
mutex_lock(&input->mutex);
if (input->users) gpio_keys_close(input);
mutex_unlock(&input->mutex);
}
return 0;
}
static int __maybe_unused gpio_keys_resume(struct device *dev)
{
struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);
struct input_dev *input = ddata->input;
int error = 0;
if (device_may_wakeup(dev))
{
gpio_keys_disable_wakeup(ddata);
}
else
{ mutex_lock(&input->mutex);
if (input->users) error = gpio_keys_open(input);
mutex_unlock(&input->mutex);
}
if (error)
return error;
gpio_keys_report_state(ddata);
return 0;
}
static SIMPLE_DEV_PM_OPS(gpio_keys_pm_ops, gpio_keys_suspend, gpio_keys_resume);
static void gpio_keys_shutdown(struct platform_device *pdev)
{
int ret;
ret = gpio_keys_suspend(&pdev->dev);
if (ret) dev_err(&pdev->dev, "failed to shutdown\n");
}
static struct platform_driver gpio_keys_device_driver = {
.probe = gpio_keys_probe,
.shutdown = gpio_keys_shutdown,
.driver = {
.name = "gpio-keys",
.pm = &gpio_keys_pm_ops,
.of_match_table = gpio_keys_of_match,
.dev_groups = gpio_keys_groups,
}
};
static int __init gpio_keys_init(void)
{
return platform_driver_register(&gpio_keys_device_driver);
}
static void __exit gpio_keys_exit(void)
{
platform_driver_unregister(&gpio_keys_device_driver);
}
late_initcall(gpio_keys_init);
module_exit(gpio_keys_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
MODULE_DESCRIPTION("Keyboard driver for GPIOs");
MODULE_ALIAS("platform:gpio-keys");
