OpenCellular/chip/npcx/pwm.c

/* Copyright (c) 2014 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 NPCX.
 *
 * On this chip, the PWM logic is implemented by the hardware FAN modules.
 */

#include "clock.h"
#include "clock_chip.h"
#include "fan.h"
#include "gpio.h"
#include "hooks.h"
#include "pwm.h"
#include "pwm_chip.h"
#include "registers.h"
#include "util.h"
#include "console.h"

#if !(DEBUG_PWM)
#define CPRINTS(...)
#else
#define CPRINTS(format, args...) cprints(CC_PWM, format, ## args)
#endif

/* PWM clock source */
enum npcx_pwm_source_clock {
	NPCX_PWM_CLOCK_APB2_LFCLK  = 0,
	NPCX_PWM_CLOCK_FX          = 1,
	NPCX_PWM_CLOCK_FR          = 2,
	NPCX_PWM_CLOCK_RESERVED    = 0x3,
	NPCX_PWM_CLOCK_UNDEF       = 0xFF
};

/* PWM heartbeat mode */
enum npcx_pwm_heartbeat_mode {
	NPCX_PWM_HBM_NORMAL    = 0,
	NPCX_PWM_HBM_25        = 1,
	NPCX_PWM_HBM_50        = 2,
	NPCX_PWM_HBM_100       = 3,
	NPCX_PWM_HBM_UNDEF     = 0xFF
};

/* Global variables */
static int pwm_init_ch;

/**
 * Preset PWM operation clock.
 *
 * @param   none
 * @return  none
 * @notes   changed when initial or HOOK_FREQ_CHANGE command
 */
void pwm_freq_changed(void)
{
	uint32_t prescaler_divider = 0;

	/* Disable PWM for module configuration */
	pwm_enable(pwm_init_ch, 0);

	if (pwm_init_ch == PWM_CH_FAN) {
		/*
		 * Using PWM Frequency and Resolution we calculate
		 * prescaler for input clock
		 */
#ifdef CONFIG_PWM_INPUT_LFCLK
		prescaler_divider = (uint32_t)(32768 /
				(pwm_channels[pwm_init_ch].freq)
				/(pwm_channels[pwm_init_ch].cycle_pulses));
#else
		prescaler_divider = (uint32_t)(
			clock_get_apb2_freq() / pwm_channels[pwm_init_ch].freq
			/ (pwm_channels[pwm_init_ch].cycle_pulses));
#endif
	} else {
		prescaler_divider = (uint32_t)(
			clock_get_apb2_freq() / pwm_channels[pwm_init_ch].freq
			/ (pwm_channels[pwm_init_ch].cycle_pulses));
	}
	/* Set clock prescalre divider to ADC module*/
	if (prescaler_divider >= 1)
		prescaler_divider = prescaler_divider - 1;
	if (prescaler_divider > 0xFFFF)
		prescaler_divider = 0xFFFF;

	/* Configure computed prescaler and resolution */
	NPCX_PRSC(pwm_channels[pwm_init_ch].channel) =
			(uint16_t)prescaler_divider;
}
DECLARE_HOOK(HOOK_FREQ_CHANGE, pwm_freq_changed, HOOK_PRIO_DEFAULT);

/**
 * Set PWM enabled.
 *
 * @param   ch      operation channel
 * @param   enabled enabled flag
 * @return  none
 */
void pwm_enable(enum pwm_channel ch, int enabled)
{
	/* Start or close PWM module */
	if (enabled)
		SET_BIT(NPCX_PWMCTL(pwm_channels[ch].channel), NPCX_PWMCTL_PWR);
	else
		CLEAR_BIT(NPCX_PWMCTL(pwm_channels[ch].channel),
				NPCX_PWMCTL_PWR);
}

/**
 * Check PWM enabled.
 *
 * @param   ch  operation channel
 * @return  enabled or not
 */
int pwm_get_enabled(enum pwm_channel ch)
{
	return IS_BIT_SET(NPCX_PWMCTL(pwm_channels[ch].channel),
			NPCX_PWMCTL_PWR);
}

/**
 * Set PWM duty cycle.
 *
 * @param   ch      operation channel
 * @param   percent duty cycle percent
 * @return  none
 */
void pwm_set_duty(enum pwm_channel ch, int percent)
{
	uint32_t resolution = 0;
	uint16_t duty_cycle = 0;

	CPRINTS("pwm0=%d", percent);
	/* Assume the fan control is active high and invert it ourselves */
	if (pwm_channels[ch].flags & PWM_CONFIG_ACTIVE_LOW)
		SET_BIT(NPCX_PWMCTL(pwm_channels[ch].channel),
				NPCX_PWMCTL_INVP);
	else
		CLEAR_BIT(NPCX_PWMCTL(pwm_channels[ch].channel),
				NPCX_PWMCTL_INVP);

	if (percent < 0)
		percent = 0;
	else if (percent > 100)
		percent = 100;
	CPRINTS("pwm1duty=%d", percent);

	resolution = NPCX_CTR(pwm_channels[ch].channel) + 1;
	duty_cycle = percent*resolution/100;
	CPRINTS("freq=0x%x", pwm_channels[ch].freq);
	CPRINTS("resolution=%d", resolution);
	CPRINTS("duty_cycle=%d", duty_cycle);
	if (percent*resolution > (duty_cycle*100))
		duty_cycle += 1;
	/* Set the duty cycle */
	if (duty_cycle > 0) {
		NPCX_DCR(pwm_channels[ch].channel) = (duty_cycle - 1);
		pwm_enable(ch, 1);
	} else {
		NPCX_DCR(pwm_channels[ch].channel) = resolution;
		pwm_enable(ch, 0);
	}
}

/**
 * Get PWM duty cycle.
 *
 * @param   ch  operation channel
 * @return  duty cycle percent
 */
int pwm_get_duty(enum pwm_channel ch)
{
	/* Return percent */
	if ((0 == pwm_get_enabled(ch)) || (NPCX_DCR(pwm_channels[ch].channel)
			> NPCX_CTR(pwm_channels[ch].channel)))
		return 0;
	else
		return (((NPCX_DCR(pwm_channels[ch].channel) + 1) * 100)
				/ (NPCX_CTR(pwm_channels[ch].channel) + 1));
}

/**
 * PWM configuration.
 *
 * @param ch                        operation channel
 * @return none
 */
void pwm_config(enum pwm_channel ch)
{
	pwm_init_ch = ch;

	/* Configure pins from GPIOs to PWM */
	if (ch == PWM_CH_FAN)
		gpio_config_module(MODULE_PWM_FAN, 1);
	else
		gpio_config_module(MODULE_PWM_KBLIGHT, 1);

	/* Disable PWM for module configuration */
	pwm_enable(ch, 0);

	/* Set PWM heartbeat mode is no heartbeat*/
	NPCX_PWMCTL(pwm_channels[ch].channel) =
			(NPCX_PWMCTL(pwm_channels[ch].channel)
			& (~(((1<<2)-1) << NPCX_PWMCTL_HB_DC_CTL)))
			| (NPCX_PWM_HBM_NORMAL << NPCX_PWMCTL_HB_DC_CTL);

	/* Set PWM operation frequence */
	pwm_freq_changed();

	/* Set PWM cycle time */
	NPCX_CTR(pwm_channels[ch].channel) =
			(pwm_channels[ch].cycle_pulses - 1);

	/* Set the duty cycle */
	NPCX_DCR(pwm_channels[ch].channel) = pwm_channels[ch].cycle_pulses;

	/* Set PWM polarity is normal*/
	CLEAR_BIT(NPCX_PWMCTL(pwm_channels[ch].channel), NPCX_PWMCTL_INVP);

	/* Select default CLK or LFCLK clock input to PWM module */
	NPCX_PWMCTLEX(pwm_channels[ch].channel) =
			(NPCX_PWMCTLEX(pwm_channels[ch].channel)
			& (~(((1<<2)-1)<<NPCX_PWMCTLEX_FCK_SEL)))
			| (NPCX_PWM_CLOCK_APB2_LFCLK<<NPCX_PWMCTLEX_FCK_SEL);

	if (ch == PWM_CH_FAN) {
#ifdef CONFIG_PWM_INPUT_LFCLK
		/* Select default LFCLK clock input to PWM module */
		SET_BIT(NPCX_PWMCTL(pwm_channels[ch].channel),
				NPCX_PWMCTL_CKSEL);
#else
		/* Select default core clock input to PWM module */
		CLEAR_BIT(NPCX_PWMCTL(pwm_channels[ch].channel),
				NPCX_PWMCTL_CKSEL);
#endif
	} else {
		/* Select default core clock input to PWM module */
		CLEAR_BIT(NPCX_PWMCTL(pwm_channels[ch].channel),
				NPCX_PWMCTL_CKSEL);
	}
}

/**
 * PWM initial.
 *
 * @param none
 * @return none
 */
static void pwm_init(void)
{
	int i;

#ifdef CONFIG_PWM_DSLEEP
	/* Enable the PWM module and delay a few clocks */
	clock_enable_peripheral(CGC_OFFSET_PWM, CGC_PWM_MASK, CGC_MODE_ALL);
#else
	/* Enable the PWM module and delay a few clocks */
	clock_enable_peripheral(CGC_OFFSET_PWM, CGC_PWM_MASK,
			CGC_MODE_RUN | CGC_MODE_SLEEP);
#endif

	for (i = 0; i < PWM_CH_COUNT; i++)
		pwm_config(i);
}

/* The chip-specific fan module initializes before this. */
DECLARE_HOOK(HOOK_INIT, pwm_init, HOOK_PRIO_DEFAULT);