leds: multicolor: Introduce a multicolor class definition

Introduce a multicolor class that groups colored LEDs
within a LED node.

The multicolor class groups monochrome LEDs and allows controlling two
aspects of the final combined color: hue and lightness. The former is
controlled via the intensity file and the latter is controlled
via brightness file.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
[squashed leds: multicolor: Fix camel case in documentation in]

3 files changed, 214 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index ed943140e1fd..1de6e8e264a0 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -30,6 +30,16 @@ config LEDS_CLASS_FLASH
 	  for the flash related features of a LED device. It can be built
 	  as a module.
 
+config LEDS_CLASS_MULTICOLOR
+	tristate "LED Multicolor Class Support"
+	depends on LEDS_CLASS
+	help
+	  This option enables the multicolor LED sysfs class in /sys/class/leds.
+	  It wraps LED class and adds multicolor LED specific sysfs attributes
+	  and kernel internal API to it. You'll need this to provide support
+	  for multicolor LEDs that are grouped together. This class is not
+	  intended for single color LEDs. It can be built as a module.
+
 config LEDS_BRIGHTNESS_HW_CHANGED
 	bool "LED Class brightness_hw_changed attribute support"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index d6b8a792c936..d684bc76d2b2 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -4,6 +4,7 @@
 obj-$(CONFIG_NEW_LEDS)			+= led-core.o
 obj-$(CONFIG_LEDS_CLASS)		+= led-class.o
 obj-$(CONFIG_LEDS_CLASS_FLASH)		+= led-class-flash.o
+obj-$(CONFIG_LEDS_CLASS_MULTICOLOR)	+= led-class-multicolor.o
 obj-$(CONFIG_LEDS_TRIGGERS)		+= led-triggers.o
 
 # LED Platform Drivers (keep this sorted, M-| sort)
diff --git a/drivers/leds/led-class-multicolor.c b/drivers/leds/led-class-multicolor.c
new file mode 100644
index 000000000000..e317408583df
--- /dev/null
+++ b/drivers/leds/led-class-multicolor.c
@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0
+// LED Multicolor class interface
+// Copyright (C) 2019-20 Texas Instruments Incorporated - http://www.ti.com/
+// Author: Dan Murphy <dmurphy@ti.com>
+
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/led-class-multicolor.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include "leds.h"
+
+int led_mc_calc_color_components(struct led_classdev_mc *mcled_cdev,
+				 enum led_brightness brightness)
+{
+	struct led_classdev *led_cdev = &mcled_cdev->led_cdev;
+	int i;
+
+	for (i = 0; i < mcled_cdev->num_colors; i++)
+		mcled_cdev->subled_info[i].brightness = brightness *
+					mcled_cdev->subled_info[i].intensity /
+					led_cdev->max_brightness;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(led_mc_calc_color_components);
+
+static ssize_t multi_intensity_store(struct device *dev,
+				struct device_attribute *intensity_attr,
+				const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct led_classdev_mc *mcled_cdev = lcdev_to_mccdev(led_cdev);
+	int nrchars, offset = 0;
+	int intensity_value[LED_COLOR_ID_MAX];
+	int i;
+	ssize_t ret;
+
+	mutex_lock(&led_cdev->led_access);
+
+	for (i = 0; i < mcled_cdev->num_colors; i++) {
+		ret = sscanf(buf + offset, "%i%n",
+			     &intensity_value[i], &nrchars);
+		if (ret != 1) {
+			ret = -EINVAL;
+			goto err_out;
+		}
+		offset += nrchars;
+	}
+
+	offset++;
+	if (offset < size) {
+		ret = -EINVAL;
+		goto err_out;
+	}
+
+	for (i = 0; i < mcled_cdev->num_colors; i++)
+		mcled_cdev->subled_info[i].intensity = intensity_value[i];
+
+	led_set_brightness(led_cdev, led_cdev->brightness);
+	ret = size;
+err_out:
+	mutex_unlock(&led_cdev->led_access);
+	return ret;
+}
+
+static ssize_t multi_intensity_show(struct device *dev,
+			      struct device_attribute *intensity_attr,
+			      char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct led_classdev_mc *mcled_cdev = lcdev_to_mccdev(led_cdev);
+	int len = 0;
+	int i;
+
+	for (i = 0; i < mcled_cdev->num_colors; i++) {
+		len += sprintf(buf + len, "%d",
+			       mcled_cdev->subled_info[i].intensity);
+		if (i < mcled_cdev->num_colors - 1)
+			len += sprintf(buf + len, " ");
+	}
+
+	buf[len++] = '\n';
+	return len;
+}
+static DEVICE_ATTR_RW(multi_intensity);
+
+static ssize_t multi_index_show(struct device *dev,
+			      struct device_attribute *multi_index_attr,
+			      char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct led_classdev_mc *mcled_cdev = lcdev_to_mccdev(led_cdev);
+	int len = 0;
+	int index;
+	int i;
+
+	for (i = 0; i < mcled_cdev->num_colors; i++) {
+		index = mcled_cdev->subled_info[i].color_index;
+		len += sprintf(buf + len, "%s", led_colors[index]);
+		if (i < mcled_cdev->num_colors - 1)
+			len += sprintf(buf + len, " ");
+	}
+
+	buf[len++] = '\n';
+	return len;
+}
+static DEVICE_ATTR_RO(multi_index);
+
+static struct attribute *led_multicolor_attrs[] = {
+	&dev_attr_multi_intensity.attr,
+	&dev_attr_multi_index.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(led_multicolor);
+
+int led_classdev_multicolor_register_ext(struct device *parent,
+				     struct led_classdev_mc *mcled_cdev,
+				     struct led_init_data *init_data)
+{
+	struct led_classdev *led_cdev;
+
+	if (!mcled_cdev)
+		return -EINVAL;
+
+	if (mcled_cdev->num_colors <= 0)
+		return -EINVAL;
+
+	if (mcled_cdev->num_colors > LED_COLOR_ID_MAX)
+		return -EINVAL;
+
+	led_cdev = &mcled_cdev->led_cdev;
+	mcled_cdev->led_cdev.groups = led_multicolor_groups;
+
+	return led_classdev_register_ext(parent, led_cdev, init_data);
+}
+EXPORT_SYMBOL_GPL(led_classdev_multicolor_register_ext);
+
+void led_classdev_multicolor_unregister(struct led_classdev_mc *mcled_cdev)
+{
+	if (!mcled_cdev)
+		return;
+
+	led_classdev_unregister(&mcled_cdev->led_cdev);
+}
+EXPORT_SYMBOL_GPL(led_classdev_multicolor_unregister);
+
+static void devm_led_classdev_multicolor_release(struct device *dev, void *res)
+{
+	led_classdev_multicolor_unregister(*(struct led_classdev_mc **)res);
+}
+
+int devm_led_classdev_multicolor_register_ext(struct device *parent,
+					     struct led_classdev_mc *mcled_cdev,
+					     struct led_init_data *init_data)
+{
+	struct led_classdev_mc **dr;
+	int ret;
+
+	dr = devres_alloc(devm_led_classdev_multicolor_release,
+			  sizeof(*dr), GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	ret = led_classdev_multicolor_register_ext(parent, mcled_cdev,
+						   init_data);
+	if (ret) {
+		devres_free(dr);
+		return ret;
+	}
+
+	*dr = mcled_cdev;
+	devres_add(parent, dr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_led_classdev_multicolor_register_ext);
+
+static int devm_led_classdev_multicolor_match(struct device *dev,
+					      void *res, void *data)
+{
+	struct led_classdev_mc **p = res;
+
+	if (WARN_ON(!p || !*p))
+		return 0;
+
+	return *p == data;
+}
+
+void devm_led_classdev_multicolor_unregister(struct device *dev,
+					     struct led_classdev_mc *mcled_cdev)
+{
+	WARN_ON(devres_release(dev,
+			       devm_led_classdev_multicolor_release,
+			       devm_led_classdev_multicolor_match, mcled_cdev));
+}
+EXPORT_SYMBOL_GPL(devm_led_classdev_multicolor_unregister);
+
+MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
+MODULE_DESCRIPTION("Multicolor LED class interface");
+MODULE_LICENSE("GPL v2");