Re: [RESEND PATCH v3 4/4] leds: Add a multicolor LED driver to group monochromatic LEDs
From: Jean-Jacques Hiblot
Date: Fri Oct 07 2022 - 02:46:40 EST
On 18/09/2022 16:54, Jacek Anaszewski wrote:
Hi Jean,
General question to this driver: since it seems that it is allowed to
have duplicate LEDs of the same color, then it will be impossible to
distinguish which of the two same colors in multi_index file will refer
to which physical LED. Are you aware of this shortcoming?
Hi Jacek,
yes I'm aware of this, but I don't think it can be a problem in a real
environment. There will probably few cases were multiple leds of the
same color are used and even fewer were those leds need to be controlled
differently.
Besides that I have two remarks below.
On 9/17/22 10:13, Jean-Jacques Hiblot wrote:
By allowing to group multiple monochrome LED into multicolor LEDs,
all involved LEDs can be controlled in-sync. This enables using effects
using triggers, etc.
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@xxxxxxxxxxxxxxx>
---
drivers/leds/rgb/Kconfig | 6 +
drivers/leds/rgb/Makefile | 1 +
drivers/leds/rgb/leds-group-multicolor.c | 153 +++++++++++++++++++++++
3 files changed, 160 insertions(+)
create mode 100644 drivers/leds/rgb/leds-group-multicolor.c
diff --git a/drivers/leds/rgb/Kconfig b/drivers/leds/rgb/Kconfig
index 204cf470beae..c2610c47a82d 100644
--- a/drivers/leds/rgb/Kconfig
+++ b/drivers/leds/rgb/Kconfig
@@ -2,6 +2,12 @@
if LEDS_CLASS_MULTICOLOR
+config LEDS_GRP_MULTICOLOR
+ tristate "Multi-color LED grouping support"
+ help
+ This option enables support for monochrome LEDs that are
+ grouped into multicolor LEDs.
+
config LEDS_PWM_MULTICOLOR
tristate "PWM driven multi-color LED Support"
depends on PWM
diff --git a/drivers/leds/rgb/Makefile b/drivers/leds/rgb/Makefile
index 0675bc0f6e18..4de087ad79bc 100644
--- a/drivers/leds/rgb/Makefile
+++ b/drivers/leds/rgb/Makefile
@@ -1,4 +1,5 @@
# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_LEDS_GRP_MULTICOLOR) += leds-group-multicolor.o
obj-$(CONFIG_LEDS_PWM_MULTICOLOR) += leds-pwm-multicolor.o
obj-$(CONFIG_LEDS_QCOM_LPG) += leds-qcom-lpg.o
diff --git a/drivers/leds/rgb/leds-group-multicolor.c
b/drivers/leds/rgb/leds-group-multicolor.c
new file mode 100644
index 000000000000..61f9e1954fc4
--- /dev/null
+++ b/drivers/leds/rgb/leds-group-multicolor.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * multi-color LED built with monochromatic LED devices
+ *
+ * Copyright 2022 Jean-Jacques Hiblot <jjhiblot@xxxxxxxxxxxxxxx>
+ */
+
+#include <linux/err.h>
+#include <linux/leds.h>
+#include <linux/led-class-multicolor.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+struct led_mcg_priv {
+ struct led_classdev_mc mc_cdev;
+ struct led_classdev **monochromatics;
+};
+
+static int led_mcg_set(struct led_classdev *cdev,
+ enum led_brightness brightness)
+{
+ struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
+ struct led_mcg_priv *priv =
+ container_of(mc_cdev, struct led_mcg_priv, mc_cdev);
+ int i;
+
+ led_mc_calc_color_components(mc_cdev, brightness);
+
+ for (i = 0; i < mc_cdev->num_colors; i++) {
+ struct led_classdev *mono = priv->monochromatics[i];
+ int actual_led_brightness;
+
+ /*
+ * Scale the intensity according the max brightness of the
+ * monochromatic LED
s/according the/according to the/
+ */
+ actual_led_brightness = DIV_ROUND_CLOSEST(
+ mono->max_brightness * mc_cdev->subled_info[i].brightness,
+ mc_cdev->led_cdev.max_brightness);
How about dropping above usage of led_mc_calc_color_components()
helper in favour of doing all required calculations here?
It would be easier for the reader to grasp the idea then.
+
+ led_set_brightness(mono, actual_led_brightness);
+ }
+
+ return 0;
+}
+
+static int led_mcg_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct led_init_data init_data = {};
+ struct led_classdev *cdev;
+ struct mc_subled *subled;
+ struct led_mcg_priv *priv;
+ int i, count, ret;
+ unsigned int max_brightness;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ count = 0;
+ max_brightness = 0;
+ for (;;) {
+ struct led_classdev *led_cdev;
+
+ led_cdev = devm_of_led_get(dev, count);
+ if (IS_ERR(led_cdev)) {
+ /* Reached the end of the list ? */
+ if (PTR_ERR(led_cdev) == -ENOENT)
+ break;
+ return dev_err_probe(dev, PTR_ERR(led_cdev),
+ "Unable to get led #%d", count);
+ }
+ count++;
+
+ priv->monochromatics = devm_krealloc(dev, priv->monochromatics,
+ count * sizeof(*priv->monochromatics),
+ GFP_KERNEL);
+ if (!priv->monochromatics)
+ return -ENOMEM;
+
+ priv->monochromatics[count - 1] = led_cdev;
+
+ max_brightness = max(max_brightness, led_cdev->max_brightness);
+ }
+
+ subled = devm_kzalloc(dev, count * sizeof(*subled), GFP_KERNEL);
+ if (!subled)
+ return -ENOMEM;
+ priv->mc_cdev.subled_info = subled;
+
+ for (i = 0; i < count; i++) {
+ struct led_classdev *led_cdev = priv->monochromatics[i];
+
+ subled[i].color_index = led_cdev->color;
+ /* configure the LED intensity to its maximum */
+ subled[i].intensity = max_brightness;
+ }
+
+ /* init the multicolor's LED class device */
+ cdev = &priv->mc_cdev.led_cdev;
+ cdev->flags = LED_CORE_SUSPENDRESUME;
+ cdev->brightness_set_blocking = led_mcg_set;
+ cdev->max_brightness = max_brightness;
+ cdev->color = LED_COLOR_ID_MULTI;
+ priv->mc_cdev.num_colors = count;
+
+ init_data.fwnode = dev_fwnode(dev);
+ ret = devm_led_classdev_multicolor_register_ext(dev,
&priv->mc_cdev,
+ &init_data);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "failed to register multicolor led for %s.\n",
+ cdev->name);
+
+ ret = led_mcg_set(cdev, cdev->brightness);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "failed to set led value for %s.",
+ cdev->name);
+
+ for (i = 0; i < count; i++) {
+ struct led_classdev *led_cdev = priv->monochromatics[i];
+
+ /* Make the sysfs of the monochromatic LED read-only */
+ led_cdev->flags |= LED_SYSFS_DISABLE;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id of_led_mcg_match[] = {
+ { .compatible = "leds-group-multicolor" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, of_led_mcg_match);
+
+static struct platform_driver led_mcg_driver = {
+ .probe = led_mcg_probe,
+ .driver = {
+ .name = "leds_group_multicolor",
+ .of_match_table = of_led_mcg_match,
+ }
+};
+module_platform_driver(led_mcg_driver);
+
+MODULE_AUTHOR("Jean-Jacques Hiblot <jjhiblot@xxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("multi-color LED group driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:leds-group-multicolor");