rambi: Control LEDs using PWM

Rambi has a pair of LEDs which are attached to the PWM fan controller.
Add support for them.  Also add a generic 'pwmduty' command which can
be used to get/set the duty cycle for any PWM channel.

Also fix rounding errors in pwm module, so that set/get duty doesn't
keep rounding down.

BUG=chrome-os-partner:22895
BRANCH=none
TEST=Boot rambi. LEDs are off.
     pwmduty -> both are 0%
     pwmduty 0 10 -> green LED on dimly
     pwmduty 1 10 -> red LED on dimly
     pwmduty 0 99 -> green LED on brightly
     pwmduty 1 100 -> red LED on brightly
     pwmduty 1 0 -> red LED off
     pwmduty 1 -1 -> red LED turns back on because fan controller is disabled
     pwmduty -> channel 0 at 99%, channel 1 disabled
     Build all platforms.  Pass all unit tests.

Change-Id: Ib0a6289a757554e696a9a0153a85bdc34e2ee2ae
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/172094

board/host/board.h

@@ -14,7 +14,6 @@
 #define CONFIG_KEYBOARD_PROTOCOL_MKBP
 #define CONFIG_POWER_BUTTON
 #undef CONFIG_WATCHDOG
-#define CONFIG_PWM
 #define CONFIG_SWITCH
 
 #undef CONFIG_CONSOLE_HISTORY

board/rambi/board.c

@@ -110,7 +110,7 @@ const struct gpio_alt_func gpio_alt_funcs[] = {
 	{GPIO_D, 0x0f, 2, MODULE_SPI},			/* SPI1 */
 	{GPIO_L, 0x3f, 15, MODULE_LPC},			/* LPC */
 	{GPIO_M, 0x33, 15, MODULE_LPC},			/* LPC */
-	{GPIO_N, 0x50, 1, MODULE_PWM_LED},		/* Power LEDs */
+	{GPIO_N, 0x50, 1, MODULE_PWM_LED, GPIO_OPEN_DRAIN}, /* Power LEDs */
 };
 const int gpio_alt_funcs_count = ARRAY_SIZE(gpio_alt_funcs);
 
@@ -152,8 +152,8 @@ BUILD_ASSERT(ARRAY_SIZE(adc_channels) == ADC_CH_COUNT);
 
 /* PWM channels */
 const struct pwm_t pwm_channels[] = {
-	[PWM_CH_LED_GREEN] = {4, 0},
-	[PWM_CH_LED_RED] = {3, 0},
+	[PWM_CH_LED_GREEN] = {4, PWM_CONFIG_ACTIVE_LOW},
+	[PWM_CH_LED_RED] = {3, PWM_CONFIG_ACTIVE_LOW},
 };
 
 BUILD_ASSERT(ARRAY_SIZE(pwm_channels) == PWM_CH_COUNT);

board/rambi/board.h

@@ -14,6 +14,7 @@
 #define CONFIG_CMD_GSV
 #define CONFIG_EXTPOWER_GPIO
 #define CONFIG_KEYBOARD_PROTOCOL_8042
+#define CONFIG_LED_COMMON
 #undef  CONFIG_PECI
 #define CONFIG_POWER_BUTTON
 #define CONFIG_POWER_BUTTON_X86

board/rambi/build.mk

@@ -9,4 +9,4 @@
 # the IC is TI Stellaris LM4
 CHIP:=lm4
 
-board-y=board.o
+board-y=board.o led.o

board/rambi/led.c

@@ -0,0 +1,45 @@
+/* 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.
+ *
+ * Battery LED control for Rambi
+ */
+
+#include "gpio.h"
+#include "hooks.h"
+#include "led_common.h"
+#include "pwm.h"
+#include "util.h"
+
+const enum ec_led_id supported_led_ids[] = {EC_LED_ID_BATTERY_LED};
+const int supported_led_ids_count = ARRAY_SIZE(supported_led_ids);
+
+void led_get_brightness_range(enum ec_led_id led_id, uint8_t *brightness_range)
+{
+	brightness_range[EC_LED_COLOR_RED] = 100;
+	brightness_range[EC_LED_COLOR_GREEN] = 100;
+}
+
+int led_set_brightness(enum ec_led_id led_id, const uint8_t *brightness)
+{
+	pwm_set_duty(PWM_CH_LED_RED, brightness[EC_LED_COLOR_RED]);
+	pwm_set_duty(PWM_CH_LED_GREEN, brightness[EC_LED_COLOR_GREEN]);
+	return EC_SUCCESS;
+}
+
+static void led_init(void)
+{
+	/* Configure GPIOs */
+	gpio_config_module(MODULE_PWM_LED, 1);
+
+	/*
+	 * Enable PWMs and set to 0% duty cycle.  If they're disabled, the LM4
+	 * seems to ground the pins instead of letting them float.
+	 */
+	pwm_enable(PWM_CH_LED_RED, 1);
+	pwm_set_duty(PWM_CH_LED_RED, 0);
+
+	pwm_enable(PWM_CH_LED_GREEN, 1);
+	pwm_set_duty(PWM_CH_LED_GREEN, 0);
+}
+DECLARE_HOOK(HOOK_INIT, led_init, HOOK_PRIO_DEFAULT);

chip/lm4/build.mk

@@ -15,13 +15,12 @@ chip-y=clock.o gpio.o hwtimer.o jtag.o system.o uart.o
 # Optional chip modules
 chip-$(CONFIG_ADC)+=adc.o chip_temp_sensor.o
 chip-$(CONFIG_EEPROM)+=eeprom.o
+chip-$(CONFIG_FAN)+=fan.o
 chip-$(CONFIG_FLASH)+=flash.o
 chip-$(CONFIG_I2C)+=i2c.o
 chip-$(CONFIG_LPC)+=lpc.o
 chip-$(CONFIG_PECI)+=peci.o
 chip-$(CONFIG_PWM)+=pwm.o
-chip-$(CONFIG_FAN)+=fan.o
-chip-$(CONFIG_PWM_KBLIGHT)+=pwm_kblight.o
 chip-$(CONFIG_SPI)+=spi.o
 chip-$(CONFIG_WATCHDOG)+=watchdog.o
 chip-$(HAS_TASK_KEYSCAN)+=keyboard_raw.o

chip/lm4/pwm.c

@@ -11,7 +11,6 @@
 #include "pwm.h"
 #include "pwm_data.h"
 #include "registers.h"
-#include "thermal.h"
 #include "util.h"
 
 /* Maximum RPM for PWM controller */
@@ -47,7 +46,10 @@ void pwm_set_duty(enum pwm_channel ch, int percent)
 	else if (percent > 100)
 		percent = 100;
 
-	duty = (MAX_PWM * percent) / 100;
+	if (pwm->flags & PWM_CONFIG_ACTIVE_LOW)
+		percent = 100 - percent;
+
+	duty = (MAX_PWM * percent + 50) / 100;
 
 	/* Always enable the channel */
 	pwm_enable(ch, 1);
@@ -59,8 +61,13 @@ void pwm_set_duty(enum pwm_channel ch, int percent)
 int pwm_get_duty(enum pwm_channel ch)
 {
 	const struct pwm_t *pwm = pwm_channels + ch;
+	int percent = ((LM4_FAN_FANCMD(pwm->channel) >> 16) * 100 + MAX_PWM / 2)
+		/ MAX_PWM;
 
-	return (LM4_FAN_FANCMD(pwm->channel) >> 16) * 100 / MAX_PWM;
+	if (pwm->flags & PWM_CONFIG_ACTIVE_LOW)
+		percent = 100 - percent;
+
+	return percent;
 }
 
 static void pwm_init(void)
@@ -109,4 +116,4 @@ static void pwm_init(void)
 		}
 	}
 }
-DECLARE_HOOK(HOOK_INIT, pwm_init, HOOK_PRIO_DEFAULT);
+DECLARE_HOOK(HOOK_INIT, pwm_init, HOOK_PRIO_INIT_PWM);

chip/stm32/pwm.c

@@ -135,6 +135,11 @@ void pwm_enable(enum pwm_channel ch, int enabled)
 		pwm_disable(ch);
 }
 
+int pwm_get_enabled(enum pwm_channel ch)
+{
+	return using_pwm[ch];
+}
+
 static void pwm_reconfigure(enum pwm_channel ch)
 {
 	using_pwm[ch] = 0;

common/build.mk

@@ -37,6 +37,7 @@ common-$(CONFIG_EXTPOWER_FALCO)+=extpower_falco.o
 common-$(CONFIG_EXTPOWER_GPIO)+=extpower_gpio.o
 common-$(CONFIG_EXTPOWER_KIRBY)+=extpower_kirby.o
 common-$(CONFIG_EXTPOWER_SPRING)+=extpower_spring.o
+common-$(CONFIG_FAN)+=pwm_fan.o
 common-$(CONFIG_FLASH)+=flash_common.o
 common-$(CONFIG_FMAP)+=fmap.o
 common-$(CONFIG_I2C)+=i2c_common.o
@@ -53,16 +54,17 @@ common-$(CONFIG_ONEWIRE)+=onewire.o
 common-$(CONFIG_POWER_BUTTON)+=power_button.o
 common-$(CONFIG_POWER_BUTTON_X86)+=power_button_x86.o
 common-$(CONFIG_PSTORE)+=pstore_commands.o
-common-$(CONFIG_FAN)+=pwm_fan.o
+common-$(CONFIG_PWM)+=pwm_common.o
+common-$(CONFIG_PWM_KBLIGHT)+=pwm_kblight.o
 common-$(CONFIG_REGULATOR_IR357X)+=regulator_ir357x.o
 common-$(CONFIG_SWITCH)+=switch.o
-common-$(CONFIG_WIRELESS)+=wireless.o
 common-$(CONFIG_TEMP_SENSOR)+=temp_sensor.o thermal.o
 common-$(CONFIG_TEMP_SENSOR_G781)+=temp_sensor_g781.o
 common-$(CONFIG_TEMP_SENSOR_TMP006)+=temp_sensor_tmp006.o
-common-$(CONFIG_USB_PORT_POWER_SMART)+=usb_port_power_smart.o
 common-$(CONFIG_USB_PORT_POWER_DUMB)+=usb_port_power_dumb.o
+common-$(CONFIG_USB_PORT_POWER_SMART)+=usb_port_power_smart.o
 common-$(CONFIG_USB_SWITCH_TSU6721)+=usb_switch_tsu6721.o
+common-$(CONFIG_WIRELESS)+=wireless.o
 common-$(HAS_TASK_CHIPSET)+=chipset.o
 common-$(HAS_TASK_CONSOLE)+=console.o
 common-$(HAS_TASK_HOSTCMD)+=host_command.o host_event_commands.o

common/pwm_common.c

@@ -0,0 +1,63 @@
+/* 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.
+ */
+
+#include "common.h"
+#include "console.h"
+#include "pwm.h"
+#include "util.h"
+
+/**
+ * Print status of a PWM channel.
+ *
+ * @param ch		Channel to print.
+ */
+static void print_channel(enum pwm_channel ch)
+{
+	if (pwm_get_enabled(ch))
+		ccprintf("  %d: %d%%\n", ch, pwm_get_duty(ch));
+	else
+		ccprintf("  %d: disabled\n", ch);
+}
+
+static int cc_pwm_duty(int argc, char **argv)
+{
+	int percent = 0;
+	int ch;
+	char *e;
+
+	if (argc < 2) {
+		ccprintf("PWM channels:\n");
+		for (ch = 0; ch < PWM_CH_COUNT; ch++)
+			print_channel(ch);
+		return EC_SUCCESS;
+	}
+
+	ch = strtoi(argv[1], &e, 0);
+	if (*e || ch < 0 || ch >= PWM_CH_COUNT)
+		return EC_ERROR_PARAM1;
+
+	if (argc > 2) {
+		percent = strtoi(argv[2], &e, 0);
+		if (*e || percent > 100) {
+			/* Bad param */
+			return EC_ERROR_PARAM1;
+		} else if (percent < 0) {
+			/* Negative = disable */
+			pwm_enable(ch, 0);
+		} else {
+			ccprintf("Setting channel %d to %d%%\n", ch, percent);
+			pwm_enable(ch, 1);
+			pwm_set_duty(ch, percent);
+		}
+	}
+
+	print_channel(ch);
+
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(pwmduty, cc_pwm_duty,
+			"[channel [<percent> | -1=disable]]",
+			"Get/set PWM duty cycles ",
+			NULL);

common/pwm_kblight.c

@@ -5,7 +5,6 @@
 
 /* PWM control module for Chromebook keyboard backlight. */
 
-#include "clock.h"
 #include "common.h"
 #include "console.h"
 #include "gpio.h"
@@ -13,15 +12,9 @@
 #include "host_command.h"
 #include "lid_switch.h"
 #include "pwm.h"
-#include "registers.h"
 #include "system.h"
-#include "task.h"
-#include "timer.h"
 #include "util.h"
 
-/* Max PWM for controller */
-#define MAX_PWM 0x1ff
-
 #define PWMKBD_SYSJUMP_TAG 0x504b  /* "PK" */
 #define PWM_HOOK_VERSION 1
 /* Saved PWM state across sysjumps */

include/hooks.h

@@ -27,6 +27,8 @@ enum hook_priority {
 	HOOK_PRIO_INIT_LID = HOOK_PRIO_FIRST + 3,
 	/* Power button inits before chipset and switch */
 	HOOK_PRIO_INIT_POWER_BUTTON = HOOK_PRIO_FIRST + 4,
+	/* PWM inits before modules which might use it (fans, LEDs) */
+	HOOK_PRIO_INIT_PWM = HOOK_PRIO_FIRST + 5,
 
 	/* Specific values to lump temperature-related hooks together */
 	HOOK_PRIO_TEMP_SENSOR = 6000,