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Commit 75929f5e authored by Ben Gardiner's avatar Ben Gardiner Committed by Kevin Hilman
Browse files

da850-evm: add UI Expander pushbuttons 



This patch adds EV_KEYs for each of the 8 pushbuttons on the UI board via a
gpio-key device.

The expander is a tca6416; it controls the SEL_{A,B,C} lines which enable and
disable the peripherals found on the UI board in addition to the 8 pushbuttons
mentioned above. The reason the existing tca6416-keypad driver is not employed
is because there was no aparent way to keep the gpio lines used as
SEL_{A,B,C} registered while simultaneously registering the pushbuttons as a
tca6416-keypad instance.

Some experimentation with the polling interval was performed; we were searching
for the largest polling interval that did not affect the feel of the
responsiveness of the buttons. It is very subjective but 200ms seems to be a
good value that accepts firm pushes but rejects very light ones. The key values
assigned to the buttons were arbitrarily chosen to be F1-F8.

Signed-off-by: default avatarBen Gardiner <bengardiner@nanometrics.ca>
Reviewed-by: default avatarChris Cordahi <christophercordahi@nanometrics.ca>
CC: Govindarajan, Sriramakrishnan <srk@ti.com>
Reviewed-by: default avatarSekhar Nori <nsekhar@ti.com>
Signed-off-by: default avatarSekhar Nori <nsekhar@ti.com>
CC: Kevin Hilman <khilman@deeprootsystems.com>
CC: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
parent 22ca4668

arch/arm/mach-davinci/board-da850-evm.c

+95 −0
Original line number Diff line number Diff line
@@ -17,8 +17,10 @@ 
#include <linux/i2c.h>

#include <linux/i2c/at24.h>

#include <linux/i2c/pca953x.h>

#include <linux/input.h>

#include <linux/mfd/tps6507x.h>

#include <linux/gpio.h>

#include <linux/gpio_keys.h>

#include <linux/platform_device.h>

#include <linux/mtd/mtd.h>

#include <linux/mtd/nand.h>
@@ -272,6 +274,87 @@ static inline void da850_evm_setup_emac_rmii(int rmii_sel) 
static inline void da850_evm_setup_emac_rmii(int rmii_sel) { }

#endif





#define DA850_KEYS_DEBOUNCE_MS	10

/*

 * At 200ms polling interval it is possible to miss an

 * event by tapping very lightly on the push button but most

 * pushes do result in an event; longer intervals require the

 * user to hold the button whereas shorter intervals require

 * more CPU time for polling.

 */

#define DA850_GPIO_KEYS_POLL_MS	200



enum da850_evm_ui_exp_pins {

	DA850_EVM_UI_EXP_SEL_C = 5,

	DA850_EVM_UI_EXP_SEL_B,

	DA850_EVM_UI_EXP_SEL_A,

	DA850_EVM_UI_EXP_PB8,

	DA850_EVM_UI_EXP_PB7,

	DA850_EVM_UI_EXP_PB6,

	DA850_EVM_UI_EXP_PB5,

	DA850_EVM_UI_EXP_PB4,

	DA850_EVM_UI_EXP_PB3,

	DA850_EVM_UI_EXP_PB2,

	DA850_EVM_UI_EXP_PB1,

};



static const char const *da850_evm_ui_exp[] = {

	[DA850_EVM_UI_EXP_SEL_C]        = "sel_c",

	[DA850_EVM_UI_EXP_SEL_B]        = "sel_b",

	[DA850_EVM_UI_EXP_SEL_A]        = "sel_a",

	[DA850_EVM_UI_EXP_PB8]          = "pb8",

	[DA850_EVM_UI_EXP_PB7]          = "pb7",

	[DA850_EVM_UI_EXP_PB6]          = "pb6",

	[DA850_EVM_UI_EXP_PB5]          = "pb5",

	[DA850_EVM_UI_EXP_PB4]          = "pb4",

	[DA850_EVM_UI_EXP_PB3]          = "pb3",

	[DA850_EVM_UI_EXP_PB2]          = "pb2",

	[DA850_EVM_UI_EXP_PB1]          = "pb1",

};



#define DA850_N_UI_PB		8



static struct gpio_keys_button da850_evm_ui_keys[] = {

	[0 ... DA850_N_UI_PB - 1] = {

		.type			= EV_KEY,

		.active_low		= 1,

		.wakeup			= 0,

		.debounce_interval	= DA850_KEYS_DEBOUNCE_MS,

		.code			= -1, /* assigned at runtime */

		.gpio			= -1, /* assigned at runtime */

		.desc			= NULL, /* assigned at runtime */

	},

};



static struct gpio_keys_platform_data da850_evm_ui_keys_pdata = {

	.buttons = da850_evm_ui_keys,

	.nbuttons = ARRAY_SIZE(da850_evm_ui_keys),

	.poll_interval = DA850_GPIO_KEYS_POLL_MS,

};



static struct platform_device da850_evm_ui_keys_device = {

	.name = "gpio-keys-polled",

	.id = 0,

	.dev = {

		.platform_data = &da850_evm_ui_keys_pdata

	},

};



static void da850_evm_ui_keys_init(unsigned gpio)

{

	int i;

	struct gpio_keys_button *button;



	for (i = 0; i < DA850_N_UI_PB; i++) {

		button = &da850_evm_ui_keys[i];

		button->code = KEY_F8 - i;

		button->desc = (char *)

				da850_evm_ui_exp[DA850_EVM_UI_EXP_PB8 + i];

		button->gpio = gpio + DA850_EVM_UI_EXP_PB8 + i;

	}

}



static int da850_evm_ui_expander_setup(struct i2c_client *client, unsigned gpio,

						unsigned ngpio, void *c)

{
@@ -304,6 +387,13 @@ static int da850_evm_ui_expander_setup(struct i2c_client *client, unsigned gpio, 
	gpio_direction_output(sel_b, 1);

	gpio_direction_output(sel_c, 1);



	da850_evm_ui_keys_init(gpio);

	ret = platform_device_register(&da850_evm_ui_keys_device);

	if (ret) {

		pr_warning("Could not register UI GPIO expander push-buttons");

		goto exp_setup_keys_fail;

	}



	ui_card_detected = 1;

	pr_info("DA850/OMAP-L138 EVM UI card detected\n");
@@ -313,6 +403,8 @@ static int da850_evm_ui_expander_setup(struct i2c_client *client, unsigned gpio, 


	return 0;



exp_setup_keys_fail:

	gpio_free(sel_c);

exp_setup_selc_fail:

	gpio_free(sel_b);

exp_setup_selb_fail:
@@ -324,6 +416,8 @@ static int da850_evm_ui_expander_setup(struct i2c_client *client, unsigned gpio, 
static int da850_evm_ui_expander_teardown(struct i2c_client *client,

					unsigned gpio, unsigned ngpio, void *c)

{

	platform_device_unregister(&da850_evm_ui_keys_device);



	/* deselect all functionalities */

	gpio_set_value_cansleep(gpio + 5, 1);

	gpio_set_value_cansleep(gpio + 6, 1);
@@ -340,6 +434,7 @@ static struct pca953x_platform_data da850_evm_ui_expander_info = { 
	.gpio_base	= DAVINCI_N_GPIO,

	.setup		= da850_evm_ui_expander_setup,

	.teardown	= da850_evm_ui_expander_teardown,

	.names		= da850_evm_ui_exp,

};



static struct i2c_board_info __initdata da850_evm_i2c_devices[] = {