zephyr: LED: Add single PWM LED support

This patch adds single PWM LED support to the common LED layer.

BUG=b:227755022, b:194430340
TEST=manual LED test on Lazor
BRANCH=none

Signed-off-by: Parth Malkan <parthmalkan@google.com>
Cq-Depend: chromium:3564077
Change-Id: Ib5070b8afb94d4771e753394f0495fe7a6811612
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3567463
Reviewed-by: Wai-Hong Tam <waihong@google.com>

5 files changed, 111 insertions, 1 deletions

diff --git a/zephyr/shim/src/led_driver/CMakeLists.txt b/zephyr/shim/src/led_driver/CMakeLists.txt
index 20c49cce6c..7c21d6827e 100644
--- a/zephyr/shim/src/led_driver/CMakeLists.txt
+++ b/zephyr/shim/src/led_driver/CMakeLists.txt
@@ -4,3 +4,4 @@
 
 zephyr_library_sources_ifdef(CONFIG_PLATFORM_EC_LED_DT      led.c)
 zephyr_library_sources_ifdef(CONFIG_PLATFORM_EC_LED_DT      led_gpio.c)
+zephyr_library_sources_ifdef(CONFIG_PLATFORM_EC_LED_DT      led_pwm.c)
diff --git a/zephyr/shim/src/led_driver/led.c b/zephyr/shim/src/led_driver/led.c
index 5adbffaa23..1e97c98a86 100644
--- a/zephyr/shim/src/led_driver/led.c
+++ b/zephyr/shim/src/led_driver/led.c
@@ -245,7 +245,8 @@ static int find_color(int node_idx, int ticks)
 	/* If period value at index 0 is not 0, it's a blinking LED */
 	if (GET_PERIOD(node_idx, 0) != 0) {
 		/*  Period is accumulated at the last index */
-		ticks = ticks % GET_PERIOD(node_idx, MAX_COLOR - 1);
+		ticks = (ticks * LED_ONE_SEC) %
+			GET_PERIOD(node_idx, MAX_COLOR - 1);
 
 		for (color_idx = 0; color_idx < MAX_COLOR; color_idx++) {
 			if (ticks < GET_PERIOD(node_idx, color_idx))
diff --git a/zephyr/shim/src/led_driver/led.h b/zephyr/shim/src/led_driver/led.h
index 5eadb61680..4354df5125 100644
--- a/zephyr/shim/src/led_driver/led.h
+++ b/zephyr/shim/src/led_driver/led.h
@@ -6,6 +6,9 @@
 #ifndef __CROS_EC_LED_H__
 #define __CROS_EC_LED_H__
 
+#define COMPAT_GPIO_LED cros_ec_gpio_led_pins
+#define COMPAT_PWM_LED  cros_ec_pwm_led_pins
+
 #define GET_PROP(id, prop)						\
 	COND_CODE_1(DT_NODE_HAS_PROP(id, prop),				\
 		    (DT_STRING_UPPER_TOKEN(id, prop)),			\
diff --git a/zephyr/shim/src/led_driver/led_gpio.c b/zephyr/shim/src/led_driver/led_gpio.c
index cdc465eafb..46d94db4dc 100644
--- a/zephyr/shim/src/led_driver/led_gpio.c
+++ b/zephyr/shim/src/led_driver/led_gpio.c
@@ -12,6 +12,8 @@
 #include <drivers/gpio.h>
 #include <logging/log.h>
 
+#if DT_HAS_COMPAT_STATUS_OKAY(COMPAT_GPIO_LED)
+
 LOG_MODULE_REGISTER(gpio_led, LOG_LEVEL_ERR);
 
 #define GPIO_LED_PINS_NODE	DT_PATH(gpio_led_pins)
@@ -72,3 +74,4 @@ void led_set_color(enum led_color color)
 		}
 	}
 }
+#endif /* DT_HAS_COMPAT_STATUS_OKAY(COMPAT_GPIO_LED) */
diff --git a/zephyr/shim/src/led_driver/led_pwm.c b/zephyr/shim/src/led_driver/led_pwm.c
new file mode 100644
index 0000000000..57cd6eb92f
--- /dev/null
+++ b/zephyr/shim/src/led_driver/led_pwm.c
@@ -0,0 +1,102 @@
+/* Copyright 2022 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 LED control.
+ */
+
+#include "led.h"
+#include "util.h"
+
+#include <devicetree.h>
+#include <drivers/pwm.h>
+#include <logging/log.h>
+
+#if DT_HAS_COMPAT_STATUS_OKAY(COMPAT_PWM_LED)
+
+LOG_MODULE_REGISTER(pwm_led, LOG_LEVEL_ERR);
+
+#define PWM_LED_PINS_NODE	DT_PATH(pwm_led_pins)
+#define LED_PIN_COUNT		(LED_COLOR_COUNT - 1)
+
+/*
+ * Struct defining LED PWM pin and duty cycle to set.
+ */
+struct pwm_pin_t {
+	const struct device *pwm;
+	uint8_t channel;
+	pwm_flags_t flags;
+	uint32_t pulse_us; /* PWM Duty cycle us */
+};
+
+/*
+ * Pin node contains LED color and array of PWM channels
+ * to alter in order to enable the given color.
+ */
+struct led_pins_node_t {
+	int led_color;
+	struct pwm_pin_t pwm_pins[LED_PIN_COUNT];
+};
+
+/*
+ * Period in us from frequency(Hz) defined in pins node
+ * period in sec = 1/freq
+ * period in usec = (1*usec_per_sec)/freq
+ * This value is also used calculate duty_cycle in us (pulse_us below).
+ * Duty cycle in perct defined in pin node is used to calculate pulse_us
+ * pulse_us = (period_us*duty_cycle_in_perct)/100
+ * Eg. freq = 500 Hz, period_us = 1000000/500 = 2000us
+ * duty_cycle = 50 %, pulse_us  = (2000*50)/100 = 1000us
+ */
+const uint32_t period_us =
+		(USEC_PER_SEC / DT_PROP(PWM_LED_PINS_NODE, pwm_frequency));
+
+#define SET_PIN(node_id, prop, i)					\
+{									\
+	.pwm = DEVICE_DT_GET(						\
+		DT_PWMS_CTLR(DT_PHANDLE_BY_IDX(node_id, prop, i))),	\
+	.channel = DT_PWMS_CHANNEL(					\
+			DT_PHANDLE_BY_IDX(node_id, prop, i)),		\
+	.flags = DT_PWMS_FLAGS(DT_PHANDLE_BY_IDX(node_id, prop, i)),	\
+	.pulse_us = DIV_ROUND_NEAREST(					\
+	   period_us * DT_PHA_BY_IDX(node_id, prop, i, value), 100),	\
+},
+
+#define SET_PWM_PIN(node_id)						\
+{									\
+	DT_FOREACH_PROP_ELEM(node_id, led_pins, SET_PIN)		\
+}
+
+#define SET_PIN_NODE(node_id)						\
+{									\
+	.led_color = GET_PROP(node_id, led_color),			\
+	.pwm_pins = SET_PWM_PIN(node_id)				\
+},
+
+struct led_pins_node_t pins_node[LED_COLOR_COUNT] = {
+	DT_FOREACH_CHILD(PWM_LED_PINS_NODE, SET_PIN_NODE)
+};
+
+/*
+ * Iterate through LED pins nodes to find the color matching node.
+ * Set all the PWM channels defined in the node to the defined value,
+ * to enable the color. Defined value is duty cycle in percentage
+ * converted to duty cycle in us (pulse_us)
+ */
+void led_set_color(enum led_color color)
+{
+	for (int i = 0; i < LED_COLOR_COUNT; i++) {
+		if (pins_node[i].led_color == color) {
+			for (int j = 0; j < LED_PIN_COUNT; j++) {
+				pwm_pin_set_usec(
+					pins_node[i].pwm_pins[j].pwm,
+					pins_node[i].pwm_pins[j].channel,
+					period_us,
+					pins_node[i].pwm_pins[j].pulse_us,
+					pins_node[i].pwm_pins[j].flags);
+			}
+			break; /* Found the matching pin node, break here */
+		}
+	}
+}
+#endif /* DT_HAS_COMPAT_STATUS_OKAY(COMPAT_PWM_LED) */