--- /dev/null
+LEDs connected to PWM (Linux compatible)
+
+Required properties:
+- compatible : should be "pwm-leds".
+
+Each LED is represented as a sub-node of the pwm-leds device. Each
+node's name represents the name of the corresponding LED.
+
+LED sub-node properties:
+- pwms : (required) LED pwm channel, see "pwms property" in
+ doc/device-tree-bindings/pwm/pwm.txt
+- label : (optional) LED label, see "label property" in
+ doc/device-tree-bindings/led/common.txt
+- max-brightness : (optional, unsigned, default 255) Maximum brightness possible
+ for the LED
+- active-low : (optional, boolean, default false) For PWMs where the LED is
+ wired to supply rather than ground
+- u-boot,default-brightness : (optional, unsigned, default 0) Initial state
+ of pwm-leds
+
+Example:
+
+leds {
+ compatible = "pwm-leds";
+ status = "okay";
+
+ blue {
+ label = "led-blue";
+ pwms = <&pwm1 0 100000 0>;
+ max-brightness = <255>;
+ u-boot,default-brightness = <127>;
+ };
+
+ green {
+ label = "led-green";
+ pwms = <&pwm2 0 100000 0>;
+ max-brightness = <255>;
+ u-boot,default-brightness = <127>;
+ };
+
+ red {
+ label = "led-red";
+ pwms = <&pwm3 0 100000 0>;
+ max-brightness = <255>;
+ u-boot,default-brightness = <127>;
+ };
+}
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2022 VK
+ * Author: Ivan Vozvakhov <i.vozvakhov@vk.team>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <led.h>
+#include <malloc.h>
+#include <dm/lists.h>
+#include <pwm.h>
+
+#define LEDS_PWM_DRIVER_NAME "led_pwm"
+
+struct led_pwm_priv {
+ struct udevice *pwm;
+ uint period; /* period in ns */
+ uint duty; /* duty cycle in ns */
+ uint channel; /* pwm channel number */
+ bool active_low; /* pwm polarity */
+ bool enabled;
+};
+
+static int led_pwm_enable(struct udevice *dev)
+{
+ struct led_pwm_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ ret = pwm_set_invert(priv->pwm, priv->channel, priv->active_low);
+ if (ret)
+ return ret;
+
+ ret = pwm_set_config(priv->pwm, priv->channel, priv->period, priv->duty);
+ if (ret)
+ return ret;
+
+ ret = pwm_set_enable(priv->pwm, priv->channel, true);
+ if (ret)
+ return ret;
+
+ priv->enabled = true;
+
+ return 0;
+}
+
+static int led_pwm_disable(struct udevice *dev)
+{
+ struct led_pwm_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ ret = pwm_set_config(priv->pwm, priv->channel, priv->period, 0);
+ if (ret)
+ return ret;
+
+ ret = pwm_set_enable(priv->pwm, priv->channel, false);
+ if (ret)
+ return ret;
+
+ priv->enabled = false;
+
+ return 0;
+}
+
+static int led_pwm_set_state(struct udevice *dev, enum led_state_t state)
+{
+ struct led_pwm_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ switch (state) {
+ case LEDST_OFF:
+ ret = led_pwm_disable(dev);
+ break;
+ case LEDST_ON:
+ ret = led_pwm_enable(dev);
+ break;
+ case LEDST_TOGGLE:
+ ret = (priv->enabled) ? led_pwm_disable(dev) : led_pwm_enable(dev);
+ break;
+ default:
+ ret = -ENOSYS;
+ }
+
+ return ret;
+}
+
+static enum led_state_t led_pwm_get_state(struct udevice *dev)
+{
+ struct led_pwm_priv *priv = dev_get_priv(dev);
+
+ return (priv->enabled) ? LEDST_ON : LEDST_OFF;
+}
+
+static int led_pwm_probe(struct udevice *dev)
+{
+ struct led_pwm_priv *priv = dev_get_priv(dev);
+ struct led_uc_plat *uc_plat = dev_get_uclass_plat(dev);
+
+ /* Ignore the top-level LED node */
+ if (!uc_plat->label)
+ return 0;
+
+ return led_pwm_set_state(dev, (priv->enabled) ? LEDST_ON : LEDST_OFF);
+}
+
+static int led_pwm_of_to_plat(struct udevice *dev)
+{
+ struct led_uc_plat *uc_plat = dev_get_uclass_plat(dev);
+ struct led_pwm_priv *priv = dev_get_priv(dev);
+ struct ofnode_phandle_args args;
+ uint def_brightness, max_brightness;
+ int ret;
+
+ /* Ignore the top-level LED node */
+ if (!uc_plat->label)
+ return 0;
+
+ ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0, &args);
+ if (ret)
+ return ret;
+
+ ret = uclass_get_device_by_ofnode(UCLASS_PWM, args.node, &priv->pwm);
+ if (ret)
+ return ret;
+
+ priv->channel = args.args[0];
+ priv->period = args.args[1];
+ priv->active_low = dev_read_bool(dev, "active-low");
+
+ def_brightness = dev_read_u32_default(dev, "u-boot,default-brightness", 0);
+ max_brightness = dev_read_u32_default(dev, "max-brightness", 255);
+ priv->enabled = !!def_brightness;
+
+ /*
+ * No need to handle pwm iverted case (active_low)
+ * because of pwm_set_invert function
+ */
+ if (def_brightness < max_brightness)
+ priv->duty = priv->period * def_brightness / max_brightness;
+ else
+ priv->duty = priv->period;
+
+ return 0;
+}
+
+static int led_pwm_bind(struct udevice *parent)
+{
+ struct udevice *dev;
+ ofnode node;
+ int ret;
+
+ dev_for_each_subnode(node, parent) {
+ struct led_uc_plat *uc_plat;
+ const char *label;
+
+ label = ofnode_read_string(node, "label");
+ if (!label)
+ label = ofnode_get_name(node);
+
+ ret = device_bind_driver_to_node(parent, LEDS_PWM_DRIVER_NAME,
+ ofnode_get_name(node),
+ node, &dev);
+ if (ret)
+ return ret;
+
+ uc_plat = dev_get_uclass_plat(dev);
+ uc_plat->label = label;
+ }
+ return 0;
+}
+
+static const struct led_ops led_pwm_ops = {
+ .set_state = led_pwm_set_state,
+ .get_state = led_pwm_get_state,
+};
+
+static const struct udevice_id led_pwm_ids[] = {
+ { .compatible = "pwm-leds" },
+ { }
+};
+
+U_BOOT_DRIVER(led_pwm) = {
+ .name = LEDS_PWM_DRIVER_NAME,
+ .id = UCLASS_LED,
+ .of_match = led_pwm_ids,
+ .ops = &led_pwm_ops,
+ .priv_auto = sizeof(struct led_pwm_priv),
+ .bind = led_pwm_bind,
+ .probe = led_pwm_probe,
+ .of_to_plat = led_pwm_of_to_plat,
+};
projects / u-boot.git / commitdiff