Embest SBC8140 : User manual : Page 58

Page | 52

.platform_data = &gpio_key_info,

},

};

Set GPIO 26 as the menu key, returning the key value KEY_F1, triggered

by a low voltage level.

2. GPIO pinmux Configuration;

The file sbc8140.h is saved under

/u-boot-03.00.02.07/board/timll/sbc8140/；

/*

* IEN - Input Enable

* IDIS - Input Disable

* PTD - Pull type Down

* PTU - Pull type Up

* DIS - Pull type selection is inactive

* EN - Pull type selection is active

* M0 - Mode 0

* The commented string gives the final mux configuration for

that pin

*/

MUX_VAL(CP(ETK_D12_ES2), (IEN | PTU | DIS | M4))

/*GPIO_26*/\

MUX_VAL(CP(ETK_D15_ES2), (IEN | PTU | DIS | M4))

/*GPIO_29*/\

Set GPIOs 26 and 29 as M4 (GPIO mode) and IEN (allow input).

3. Driver Design;

The source file: gpio_keys.c is saved under

/linux-2.6.32-sbc8140/drivers/input/keyboard/;

Call platform_driver_register to register gpio_keys driver;

static struct platform_driver gpio_keys_device_driver = {

.probe = gpio_keys_probe,

.remove = __devexit_p(gpio_keys_remove),

.driver = {

.name = "gpio-keys",