Lars: Add PWM keyboard backlight support

+ pwm settings

BUG=None
BRANCH=lars
TEST=`make BOARD=lars -j`, OS can boot up normally

Change-Id: I8703261736802a81323077a85262da7d7a80cbc1
Signed-off-by: Ryan Zhang <Ryan.Zhang@quantatw.com>
Reviewed-on: https://chromium-review.googlesource.com/315911
Reviewed-by: Shawn N <shawnn@chromium.org>

board/lars/board.c

@@ -26,6 +26,8 @@
 #include "pi3usb9281.h"
 #include "power.h"
 #include "power_button.h"
+#include "pwm.h"
+#include "pwm_chip.h"
 #include "spi.h"
 #include "switch.h"
 #include "system.h"
@@ -103,6 +105,12 @@ const struct adc_t adc_channels[] = {
 };
 BUILD_ASSERT(ARRAY_SIZE(adc_channels) == ADC_CH_COUNT);
 
+/* PWM channels. Must be in the exactly same order as in enum pwm_channel. */
+const struct pwm_t pwm_channels[] = {
+	{1, 0},
+};
+BUILD_ASSERT(ARRAY_SIZE(pwm_channels) == PWM_CH_COUNT);
+
 const struct i2c_port_t i2c_ports[]  = {
 	{"pmic",     MEC1322_I2C0_0, 400,  GPIO_I2C0_0_SCL, GPIO_I2C0_0_SDA},
 	{"muxes",    MEC1322_I2C0_1, 400,  GPIO_I2C0_1_SCL, GPIO_I2C0_1_SDA},

board/lars/board.h

@@ -59,6 +59,8 @@
 #define CONFIG_POWER_BUTTON_X86
 #define CONFIG_POWER_COMMON
 #define CONFIG_POWER_SHUTDOWN_PAUSE_IN_S5
+#define CONFIG_PWM
+#define CONFIG_PWM_KBLIGHT
 /* All data won't fit in data RAM.  So, moving boundary slightly. */
 #undef CONFIG_RO_SIZE
 #define CONFIG_RO_SIZE (104 * 1024)
@@ -150,6 +152,12 @@ enum als_id {
 	ALS_COUNT,
 };
 
+enum pwm_channel {
+	PWM_CH_KBLIGHT,
+	/* Number of PWM channels */
+	PWM_CH_COUNT,
+};
+
 /* power signal definitions */
 enum power_signal {
 	X86_RSMRST_L_PWRGD = 0,

board/lars/gpio.inc

@@ -50,7 +50,6 @@ GPIO(WLAN_OFF_L,		PIN(132), GPIO_OUT_HIGH)                /* Empty */
 GPIO(PWRLED_L,			PIN(133), GPIO_OUT_LOW)
 /* RCIN# line to PCH for 8042 emulation */
 GPIO(PCH_RCIN_L,		PIN(135), GPIO_ODR_HIGH)
-GPIO(NC_136,			PIN(136), GPIO_INPUT | GPIO_PULL_UP)
 GPIO(LDO_EN,			PIN(211), GPIO_OUT_LOW)
 GPIO(NC_145,			PIN(145), GPIO_INPUT | GPIO_PULL_UP)
 GPIO(NC_147,			PIN(147), GPIO_INPUT | GPIO_PULL_UP)
@@ -140,6 +139,9 @@ ALTERNATE(PIN_MASK(14, 0x01), 3, MODULE_PWM, 0)
 /* TACH2PWM_OUT - GPIO034 */
 ALTERNATE(PIN_MASK(3,  0x10), 3, MODULE_PWM, 0)
 
+/* PWM for KBLight */
+ALTERNATE(PIN_MASK(13,  0x40), 1, MODULE_PWM_KBLIGHT, 0) /* GP136 PWM1 */
+
 /* ADC pins */
 /* ADC1 - GPIO057 / PPVAR_BOOSTIN_SENSE */
 ALTERNATE(PIN_MASK(5,  0x80), 1, MODULE_ADC, GPIO_ANALOG)