Difference between revisions of "GPIO keys"
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* APF51: GPIO1_3 | * APF51: GPIO1_3 | ||
| − | == | + | ==Configuration== |
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First, you need to enable the gpio_keys in your kernel. | First, you need to enable the gpio_keys in your kernel. | ||
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</pre> | </pre> | ||
| − | Then, in your '' | + | Then, in your ''apfXX-dev.c'', you would need to define your GPIO button <b>before</b> the variable ''platform_devices[]'' and also include gpio_keys.h and input.h. his code is already implemented for the APF27, APF28 and APF51 so the source code hereafter (for the APF27) is only present as a reference sample to understand how to activate a GPIO KEY driver. |
<source lang="c"> | <source lang="c"> | ||
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}; | }; | ||
</source> | </source> | ||
| + | |||
| + | ==Test== | ||
| + | <pre class="apf"> | ||
| + | # cat /dev/input/event0 | ||
| + | </pre> | ||
| + | Then you should see weirds characters '''when pressing''' the user button of the apf51_dev board: | ||
| + | <pre class="apf"> | ||
| + | T | ||
| + | ����T | ||
| + | �T | ||
| + | � | ||
| + | ��T | ||
| + | %� | ||
| + | </pre> | ||
| + | * if the test wiped out your console, you can get it back with: | ||
| + | <pre class="apf"> | ||
| + | # reset | ||
| + | </pre> | ||
| + | |||
| + | You also can use the tool ''evtest''. | ||
| + | |||
| + | <pre class="config"> | ||
| + | Hardware handling ---> | ||
| + | [*] input-tools | ||
| + | [*] evtest | ||
| + | </pre> | ||
| + | |||
| + | <pre class="apf"> | ||
| + | # evtest /dev/input/event0 | ||
| + | ... | ||
| + | Event: time 1335981358.550329, type 22 (EV_PWR), code 0 (), value 1 | ||
| + | Event: time 1335981358.550330, -------------- SYN_REPORT ------------ | ||
| + | Event: time 1335981358.550329, type 22 (EV_PWR), code 0 (), value 0 | ||
| + | Event: time 1335981358.550330, -------------- SYN_REPORT ------------ | ||
| + | |||
| + | </pre> | ||
[[Category:UserInput]] | [[Category:UserInput]] | ||
Revision as of 22:44, 16 May 2012
Introduction
How to use gpio-keys driver to read states of the user switch of your Armadeus board. Your APF51|APF27|APF28 development board feature a user switch connected to a GPIO pin. The driver gpio-keys translates GPIO events in key/button events. Here are the GPIO used for the user button/switch for each APF board:
- APF27: GPIO_PORTF | 13
- APF28: PINID_GPMI_CE1N (Bank 0 - bit 17)
- APF51: GPIO1_3
Configuration
First, you need to enable the gpio_keys in your kernel.
Device Drivers --->
Input device support --->
<*> Event interface
[*] Keyboards --->
<*> GPIO Buttons
Then, in your apfXX-dev.c, you would need to define your GPIO button before the variable platform_devices[] and also include gpio_keys.h and input.h. his code is already implemented for the APF27, APF28 and APF51 so the source code hereafter (for the APF27) is only present as a reference sample to understand how to activate a GPIO KEY driver.
#include <linux/gpio_keys.h>
#include <linux/input.h>
/* GPIO KEYS */
#if defined(CONFIG_KEYBOARD_GPIO) || defined(CONFIG_KEYBOARD_GPIO_MODULE)
static struct gpio_keys_button apf27dev_gpio_keys[] = {
{
.code = BTN_EXTRA, /* See include/linux/input.h */
.gpio = (GPIO_PORTF | 13), /* GPIO number */
.active_low = 1,
.desc = "s1", /* Button description*/
.wakeup = 0,
},
};
static struct gpio_keys_platform_data apf27dev_gpio_keys_data = {
.buttons = apf27dev_gpio_keys,
.nbuttons = ARRAY_SIZE(apf27dev_gpio_keys),
};
static struct platform_device apf27dev_gpio_keys_device = {
.name = "gpio-keys",
.id = -1,
.dev = {
.platform_data = &apf27dev_gpio_keys_data,
},
};
#endif /* CONFIG_KEYBOARD_GPIO */
Add the button to get it recognized by the card.
static struct platform_device *platform_devices[] __initdata = {
#if defined(CONFIG_KEYBOARD_GPIO) || defined(CONFIG_KEYBOARD_GPIO_MODULE)
&apf27dev_gpio_keys_device,
#endif
ALSA_SOUND
};
Test
# cat /dev/input/event0
Then you should see weirds characters when pressing the user button of the apf51_dev board:
T
����T
�T
�
��T
%�
- if the test wiped out your console, you can get it back with:
# reset
You also can use the tool evtest.
Hardware handling --->
[*] input-tools
[*] evtest
# evtest /dev/input/event0 ... Event: time 1335981358.550329, type 22 (EV_PWR), code 0 (), value 1 Event: time 1335981358.550330, -------------- SYN_REPORT ------------ Event: time 1335981358.550329, type 22 (EV_PWR), code 0 (), value 0 Event: time 1335981358.550330, -------------- SYN_REPORT ------------
