common/pwm_kblight.c

/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

/* PWM control module for Chromebook keyboard backlight. */

#include "common.h"
#include "console.h"
#include "gpio.h"
#include "hooks.h"
#include "host_command.h"
#include "lid_switch.h"
#include "pwm.h"
#include "system.h"
#include "util.h"

#define PWMKBD_SYSJUMP_TAG 0x504b  /* "PK" */
#define PWM_HOOK_VERSION 1
/* Saved PWM state across sysjumps */
struct pwm_kbd_state {
	uint8_t kblight_en;
	uint8_t kblight_percent;
};

/*****************************************************************************/
/* Console commands */

static int command_kblight(int argc, char **argv)
{
	if (argc >= 2) {
		char *e;
		int i = strtoi(argv[1], &e, 0);
		if (*e)
			return EC_ERROR_PARAM1;
		pwm_set_duty(PWM_CH_KBLIGHT, i);
	}

	ccprintf("Keyboard backlight: %d%%\n", pwm_get_duty(PWM_CH_KBLIGHT));
	return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(kblight, command_kblight,
			"percent",
			"Set keyboard backlight");

/*****************************************************************************/
/* Host commands */

int pwm_command_get_keyboard_backlight(struct host_cmd_handler_args *args)
{
	struct ec_response_pwm_get_keyboard_backlight *r = args->response;

	r->percent = pwm_get_duty(PWM_CH_KBLIGHT);
	r->enabled = pwm_get_enabled(PWM_CH_KBLIGHT);
	args->response_size = sizeof(*r);

	return EC_RES_SUCCESS;
}
DECLARE_HOST_COMMAND(EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT,
		     pwm_command_get_keyboard_backlight,
		     EC_VER_MASK(0));

int pwm_command_set_keyboard_backlight(struct host_cmd_handler_args *args)
{
	const struct ec_params_pwm_set_keyboard_backlight *p = args->params;

	pwm_set_duty(PWM_CH_KBLIGHT, p->percent);

	return EC_RES_SUCCESS;
}
DECLARE_HOST_COMMAND(EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT,
		     pwm_command_set_keyboard_backlight,
		     EC_VER_MASK(0));

/*****************************************************************************/
/* Hooks */

static void pwm_kblight_init(void)
{
	const struct pwm_kbd_state *prev;
	int version, size;

	prev = (const struct pwm_kbd_state *)
		system_get_jump_tag(PWMKBD_SYSJUMP_TAG, &version, &size);
	if (prev && version == PWM_HOOK_VERSION && size == sizeof(*prev)) {
		/* Restore previous state. */
		pwm_enable(PWM_CH_KBLIGHT, prev->kblight_en);
		pwm_set_duty(PWM_CH_KBLIGHT, prev->kblight_percent);
	} else {
		/* Enable keyboard backlight control, turned down */
		pwm_set_duty(PWM_CH_KBLIGHT, 0);
		pwm_enable(PWM_CH_KBLIGHT, 1);
	}
}
DECLARE_HOOK(HOOK_INIT, pwm_kblight_init, HOOK_PRIO_DEFAULT);

static void pwm_kblight_preserve_state(void)
{
	struct pwm_kbd_state state;

	state.kblight_en = pwm_get_enabled(PWM_CH_KBLIGHT);
	state.kblight_percent = pwm_get_duty(PWM_CH_KBLIGHT);

	system_add_jump_tag(PWMKBD_SYSJUMP_TAG, PWM_HOOK_VERSION,
			    sizeof(state), &state);
}
DECLARE_HOOK(HOOK_SYSJUMP, pwm_kblight_preserve_state, HOOK_PRIO_DEFAULT);

static void pwm_kblight_suspend(void)
{
	pwm_set_duty(PWM_CH_KBLIGHT, 0);
}
DECLARE_HOOK(HOOK_CHIPSET_SUSPEND, pwm_kblight_suspend, HOOK_PRIO_DEFAULT);

static void pwm_kblight_shutdown(void)
{
	pwm_set_duty(PWM_CH_KBLIGHT, 0);
}
DECLARE_HOOK(HOOK_CHIPSET_SHUTDOWN, pwm_kblight_shutdown, HOOK_PRIO_DEFAULT);

static void pwm_kblight_lid_change(void)
{
	pwm_enable(PWM_CH_KBLIGHT, lid_is_open());
}
DECLARE_HOOK(HOOK_LID_CHANGE, pwm_kblight_lid_change, HOOK_PRIO_DEFAULT);