Re: [PATCH v3 6/9] leds: multicolor: Introduce a multicolor class definition

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Hi Dan,

Thank you for the v5.

I will confine myself to commenting only some parts since
the rest will undergo rework due to removal of sync API.

On 5/23/19 9:08 PM, Dan Murphy wrote:
Introduce a multicolor class that groups colored LEDs
within a LED node.

The framework allows for dynamically setting individual LEDs
or setting brightness levels of LEDs and updating them virtually
simultaneously.

Signed-off-by: Dan Murphy <dmurphy@xxxxxx>
---
  drivers/leds/Kconfig                 |  10 +
  drivers/leds/Makefile                |   1 +
  drivers/leds/led-class-multicolor.c  | 421 +++++++++++++++++++++++++++
  include/linux/led-class-multicolor.h |  95 ++++++
  4 files changed, 527 insertions(+)
  create mode 100644 drivers/leds/led-class-multicolor.c
  create mode 100644 include/linux/led-class-multicolor.h

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 0414adebb177..0696a13c9527 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -29,6 +29,16 @@ config LEDS_CLASS_FLASH
  	  for the flash related features of a LED device. It can be built
  	  as a module.
+config LEDS_CLASS_MULTI_COLOR
+	tristate "LED Mulit Color LED 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.

extra whitespace:

s/ It can/It can/

[...]
+
+static int multicolor_set_brightness(struct led_classdev *led_cdev,
+			     enum led_brightness brightness)
+{
+	struct led_classdev_mc *mcled_cdev = lcdev_to_mccdev(led_cdev);
+	struct led_classdev_mc_data *data = mcled_cdev->data;
+	struct led_multicolor_ops *ops = mcled_cdev->ops;
+	struct led_classdev_mc_priv *priv;
+	unsigned long state = brightness;
+	int adj_value;
+	ssize_t ret = -EINVAL;
+
+	mutex_lock(&led_cdev->led_access);
+
+	if (ops->set_module_brightness) {
+		ret = ops->set_module_brightness(mcled_cdev, state);
+		goto unlock;
+	}
+
+	list_for_each_entry(priv, &data->color_list, list) {
+		if (state && priv->brightness && priv->max_brightness) {
+			adj_value = state * ((priv->brightness * 100) / priv->max_brightness);
+			adj_value = adj_value / 100;

Why the multiplication an then division by 100? And priv->max_brightness
stays unaltered? This changes the proportions. My python script works
just fine without those.

+		} else
+			adj_value = LED_OFF;
+
+		ret = ops->set_color_brightness(priv->mcled_cdev,
+						priv->color_id,	adj_value);
+		if (ret < 0)
+			goto unlock;
+	}
+
+unlock:
+	mutex_unlock(&led_cdev->led_access);
+	return ret;
+}
[...]
+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;
+	struct led_multicolor_ops *ops;
+	struct led_classdev_mc_data *data;
+	int ret;
+	int i;
+
+	if (!mcled_cdev)
+		return -EINVAL;
+
+	ops = mcled_cdev->ops;
+	if (!ops || !ops->set_color_brightness)
+		return -EINVAL;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	mcled_cdev->data = data;
+	led_cdev = &mcled_cdev->led_cdev;
+
+	if (led_cdev->brightness_set_blocking)
+		led_cdev->brightness_set_blocking = multicolor_set_brightness;

This is weird. In leds-lp50xx.c you don't initialize
brightness_set_blocking and this still works?

I believe this is kind of omission.

And it is not reasonable to just override driver supplied op with
generic one just like that.

I propose to initialize brightness_set or brightness_set_blocking
op as we used to do it for monochrome LEDs. Those function(s) on
driver side will either use device's hardware support for setting
color lightness, or will call a generic function provided by
LED multi color class for calculating intensities of all colors
it comprises in the cluster.

I know this is different to what we've discussed on IRC, but now
it looks for me the most reasonable way to go.

+	INIT_LIST_HEAD(&data->color_list);
+
+	/* Register led class device */
+	ret = led_classdev_register_ext(parent, led_cdev, init_data);
+	if (ret)
+		return ret;
+
+	ret = led_multicolor_init_color_dir(data, mcled_cdev);
+	if (ret)
+		return ret;
+
+	/* Select the sysfs attributes to be created for the device */
+	for (i = 0; i < mcled_cdev->num_leds; i++) {
+		ret = led_multicolor_init_color(data, mcled_cdev,
+						mcled_cdev->available_colors[i]);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+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);
+}
+
+/**
+ * devm_of_led_classdev_register - resource managed led_classdev_register()
+ *
+ * @parent: parent of LED device
+ * @led_cdev: the led_classdev structure for this device.
+ */
+int devm_led_classdev_multicolor_register(struct device *parent,
+					  struct led_classdev_mc *mcled_cdev)
+{
+	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(parent, mcled_cdev);
+	if (ret) {
+		devres_free(dr);
+		return ret;
+	}
+
+	*dr = mcled_cdev;
+	devres_add(parent, dr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_led_classdev_multicolor_register);
+
+static int devm_led_classdev_multicolor_match(struct device *dev,
+					      void *res, void *data)
+{
+	struct mcled_cdev **p = res;
+
+	if (WARN_ON(!p || !*p))
+		return 0;
+
+	return *p == data;
+}
+
+/**
+ * devm_led_classdev_multicolor_unregister() - resource managed
+ *					led_classdev_multicolor_unregister()
+ * @parent: The device to unregister.
+ * @mcled_cdev: the led_classdev_mc structure for this device.
+ */
+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@xxxxxx>");
+MODULE_DESCRIPTION("Multi Color LED class interface");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/led-class-multicolor.h b/include/linux/led-class-multicolor.h
new file mode 100644
index 000000000000..f9e71d984b03
--- /dev/null
+++ b/include/linux/led-class-multicolor.h
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* LED Multicolor class interface
+ * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
+ */

Let's have C++ comment style also here.

+#ifndef __LINUX_MULTICOLOR_LEDS_H_INCLUDED
+#define __LINUX_MULTICOLOR_LEDS_H_INCLUDED
+
+#include <linux/leds.h>
+#include <dt-bindings/leds/common.h>
[...]


--
Best regards,
Jacek Anaszewski



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