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/* Copyright (c) 2012 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 Chrome EC */
#include "board.h"
#include "console.h"
#include "gpio.h"
#include "pwm.h"
#include "registers.h"
#include "uart.h"
#include "util.h"
/* Maximum RPM for fan controller */
#define MAX_RPM 0x1fff
/* Max PWM for fan controller */
#define MAX_PWM 0x1ff
/* Scaling factor for requested/actual RPM for CPU fan. We need this because
* the fan controller on Blizzard filters tach pulses that are less than 64
* 15625Hz ticks apart, which works out to ~7000rpm on an unscaled fan. By
* telling the controller we actually have twice as many edges per revolution,
* the controller can handle fans that actually go twice as fast. See
* crosbug.com/p/7718. */
#define CPU_FAN_SCALE 2
/* Configures the GPIOs for the fan module. */
static void configure_gpios(void)
{
#ifdef BOARD_link
/* PK6 alternate function 1 = channel 1 PWM */
gpio_set_alternate_function(LM4_GPIO_K, 0x40, 1);
/* PM6:7 alternate function 1 = channel 0 PWM/tach */
gpio_set_alternate_function(LM4_GPIO_M, 0xc0, 1);
#else
/* PK6 alternate function 1 = channel 1 PWM */
gpio_set_alternate_function(LM4_GPIO_K, 0x40, 1);
/* PN6:7 alternate function 1 = channel 4 PWM/tach */
gpio_set_alternate_function(LM4_GPIO_N, 0xc0, 1);
#endif
}
int pwm_get_fan_rpm(void)
{
return (LM4_FAN_FANCST(FAN_CH_CPU) & MAX_RPM) * CPU_FAN_SCALE;
}
int pwm_set_fan_target_rpm(int rpm)
{
/* Apply fan scaling */
if (rpm > 0)
rpm /= CPU_FAN_SCALE;
/* Treat out-of-range requests as requests for maximum fan speed */
if (rpm < 0 || rpm > MAX_RPM)
rpm = MAX_RPM;
LM4_FAN_FANCMD(FAN_CH_CPU) = rpm;
return EC_SUCCESS;
}
int pwm_get_keyboard_backlight(void)
{
return ((LM4_FAN_FANCMD(FAN_CH_KBLIGHT) >> 16) * 100 +
MAX_PWM / 2) / MAX_PWM;
}
int pwm_set_keyboard_backlight(int percent)
{
LM4_FAN_FANCMD(FAN_CH_KBLIGHT) = ((percent * MAX_PWM + 50) / 100) << 16;
return EC_SUCCESS;
}
/*****************************************************************************/
/* Console commands */
static int command_fan_info(int argc, char **argv)
{
uart_printf("Fan actual speed: %4d rpm\n", pwm_get_fan_rpm());
uart_printf(" target speed: %4d rpm\n",
(LM4_FAN_FANCMD(FAN_CH_CPU) & MAX_RPM) * CPU_FAN_SCALE);
uart_printf(" duty cycle: %d%%\n",
((LM4_FAN_FANCMD(FAN_CH_CPU) >> 16)) * 100 / MAX_PWM);
uart_printf(" status: %d\n",
(LM4_FAN_FANSTS >> (2 * FAN_CH_CPU)) & 0x03);
return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(faninfo, command_fan_info);
static int command_fan_set(int argc, char **argv)
{
int rpm = 0;
char *e;
int rv;
if (argc < 2) {
uart_puts("Usage: fanset <rpm>\n");
return EC_ERROR_UNKNOWN;
}
rpm = strtoi(argv[1], &e, 0);
if (*e) {
uart_puts("Invalid speed\n");
return EC_ERROR_UNKNOWN;
}
uart_printf("Setting fan speed to %d rpm...\n", rpm);
/* Move the fan to automatic control */
if (LM4_FAN_FANCH(FAN_CH_CPU) & 0x0001) {
LM4_FAN_FANCTL &= ~(1 << FAN_CH_CPU);
LM4_FAN_FANCH(FAN_CH_CPU) &= ~0x0001;
LM4_FAN_FANCTL |= (1 << FAN_CH_CPU);
}
rv = pwm_set_fan_target_rpm(rpm);
if (rv == EC_SUCCESS)
uart_printf("Done.\n");
return rv;
}
DECLARE_CONSOLE_COMMAND(fanset, command_fan_set);
/* TODO: this is a temporary command for debugging tach issues */
static int command_fan_duty(int argc, char **argv)
{
int d = 0, pwm;
char *e;
if (argc < 2) {
uart_puts("Usage: fanduty <percent>\n");
return EC_ERROR_UNKNOWN;
}
d = strtoi(argv[1], &e, 0);
if (*e) {
uart_puts("Invalid duty cycle\n");
return EC_ERROR_UNKNOWN;
}
pwm = (MAX_PWM * d) / 100;
uart_printf("Setting fan duty cycle to %d%% = 0x%x...\n", d, pwm);
/* Move the fan to manual control */
if (!(LM4_FAN_FANCH(FAN_CH_CPU) & 0x0001)) {
LM4_FAN_FANCTL &= ~(1 << FAN_CH_CPU);
LM4_FAN_FANCH(FAN_CH_CPU) |= 0x0001;
LM4_FAN_FANCTL |= (1 << FAN_CH_CPU);
}
/* Set the duty cycle */
LM4_FAN_FANCMD(FAN_CH_CPU) = pwm << 16;
return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(fanduty, command_fan_duty);
static int command_kblight(int argc, char **argv)
{
char *e;
int rv;
int i;
if (argc < 2) {
uart_printf("Keyboard backlight is at %d%%\n",
pwm_get_keyboard_backlight());
return EC_SUCCESS;
}
i = strtoi(argv[1], &e, 0);
if (*e) {
uart_puts("Invalid percent\n");
return EC_ERROR_UNKNOWN;
}
uart_printf("Setting keyboard backlight to %d%%...\n", i);
rv = pwm_set_keyboard_backlight(i);
if (rv == EC_SUCCESS)
uart_printf("Done.\n");
return rv;
}
DECLARE_CONSOLE_COMMAND(kblight, command_kblight);
/*****************************************************************************/
/* Initialization */
int pwm_init(void)
{
volatile uint32_t scratch __attribute__((unused));
/* Enable the fan module and delay a few clocks */
LM4_SYSTEM_RCGCFAN = 1;
scratch = LM4_SYSTEM_RCGCFAN;
/* Configure GPIOs */
configure_gpios();
/* Disable all fans */
LM4_FAN_FANCTL = 0;
/* Configure CPU fan:
* 0x8000 = bit 15 = auto-restart
* 0x0000 = bit 14 = slow acceleration
* 0x0000 = bits 13:11 = no hysteresis
* 0x0000 = bits 10:8 = start period (2<<0) edges
* 0x0000 = bits 7:6 = no fast start
* 0x0020 = bits 5:4 = average 4 edges when calculating RPM
* 0x000c = bits 3:2 = 8 pulses per revolution
* (see note at top of file)
* 0x0000 = bit 0 = automatic control */
LM4_FAN_FANCH(FAN_CH_CPU) = 0x802c;
/* Configure keyboard backlight:
* 0x0000 = bit 15 = auto-restart
* 0x0000 = bit 14 = slow acceleration
* 0x0000 = bits 13:11 = no hysteresis
* 0x0000 = bits 10:8 = start period (2<<0) edges
* 0x0000 = bits 7:6 = no fast start
* 0x0000 = bits 5:4 = average 4 edges when calculating RPM
* 0x0000 = bits 3:2 = 4 pulses per revolution
* 0x0001 = bit 0 = manual control */
LM4_FAN_FANCH(FAN_CH_KBLIGHT) = 0x0001;
/* Set initial fan speed to maximum, backlight off */
pwm_set_fan_target_rpm(-1);
pwm_set_keyboard_backlight(0);
/* Enable CPU fan and keyboard backlight */
LM4_FAN_FANCTL |= (1 << FAN_CH_CPU) | (1 << FAN_CH_KBLIGHT);
return EC_SUCCESS;
}
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