arch/arm/mach-imx/mach-diamond3.c

/*
 * Copyright (C) 2015 Nest Labs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/cpufreq.h>

#ifdef CONFIG_MACH_DIAMOND3_HIGH_CPU_CLK
#define D3_MAX_CPU_CORE_CLK 792000
#else
#define D3_MAX_CPU_CORE_CLK 396000
#endif

extern void (*pm_halt_system)(void);
extern void snvs_poweroff(void);

static void reset_mcu(void)
{
	int mcu_reset_gpio = -1;
	struct device_node *np;
	np = of_find_node_by_name(NULL, "sensor-mcu-gpios");
	if(np != NULL)
	{
		mcu_reset_gpio = of_get_named_gpio(np, "output-gpios", 0);
	}

	if(gpio_is_valid(mcu_reset_gpio))
	{
		/* Drop down reset pin and wait for it to discharge first */
		gpio_direction_output(mcu_reset_gpio, 0);
		msleep(5000);
		/* Toggle reset pin to reset MCU */
		gpio_direction_output(mcu_reset_gpio, 1);
		msleep(20);
		gpio_direction_output(mcu_reset_gpio, 0);
	}
}

static void diamond_halt(void)
{
	/* Reset MCU first so MCU can hold down VCC main*/
	/* do NOT perform pmic shut down, we'll rely on MCU to kill VCC main*/
	reset_mcu();
}

static void diamond_register_pm_halt(void)
{
	pm_halt_system = diamond_halt;
}

static void diamond_set_max_core_clk(void)
{
	struct cpufreq_policy *policy = cpufreq_cpu_get(0);
	if(policy != NULL)
	{
		policy->user_policy.max = D3_MAX_CPU_CORE_CLK;
		cpufreq_update_policy(0);
	}
}

void diamond_late_init(void)
{
	diamond_register_pm_halt();
	diamond_set_max_core_clk();
}
EXPORT_SYMBOL(diamond_register_pm_halt);