Date:   Mon, 23 Sep 2019 10:14:17 -0500
From:   Dan Murphy <dmurphy@...com>
To:     Jacek Anaszewski <jacek.anaszewski@...il.com>, <pavel@....cz>
CC:     <linux-leds@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v8 6/9] leds: multicolor: Introduce a multicolor class
 definition

Jacek

On 9/21/19 8:30 AM, Jacek Anaszewski wrote:
> Dan,
>
> On 9/20/19 7:41 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.
> Let's update this to the corresponding changed fragment from
> the documentation after we finally agree upon it.

Ack


>
>> Signed-off-by: Dan Murphy <dmurphy@...com>
>> ---
>>   drivers/leds/Kconfig                 |  10 +
>>   drivers/leds/Makefile                |   1 +
>>   drivers/leds/led-class-multicolor.c  | 316 +++++++++++++++++++++++++++
>>   include/linux/led-class-multicolor.h |  76 +++++++
>>   4 files changed, 403 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 6e7703fd03d0..cfb1ebb6517f 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_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.
>> +
>>   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 2da39e896ce8..841038cfe35b 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_MULTI_COLOR)	+= led-class-multicolor.o
>>   obj-$(CONFIG_LEDS_TRIGGERS)		+= led-triggers.o
>>   
>>   # LED Platform Drivers
>> diff --git a/drivers/leds/led-class-multicolor.c b/drivers/leds/led-class-multicolor.c
>> new file mode 100644
>> index 000000000000..5e0e3fce482b
>> --- /dev/null
>> +++ b/drivers/leds/led-class-multicolor.c
>> @@ -0,0 +1,316 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +// LED Multi Color class interface
>> +// Copyright (C) 2019 Texas Instruments Incorporated - http://www.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"
>> +
>> +#define INTENSITY_NAME		"_intensity"
>> +#define MAX_INTENSITY_NAME	"_max_intensity"
>> +
>> +struct led_mc_color_entry {
>> +	struct led_classdev_mc *mcled_cdev;
>> +
>> +	struct device_attribute max_intensity_attr;
>> +	struct device_attribute intensity_attr;
>> +
>> +	enum led_brightness max_intensity;
>> +	enum led_brightness intensity;
>> +
>> +	struct list_head list;
>> +
>> +	int led_color_id;
>> +};
>> +
>> +void led_mc_calc_brightness(struct led_classdev_mc *mcled_cdev,
>> +			    enum led_brightness brightness,
>> +			    int brightness_val[])
>> +{
>> +	struct led_classdev_mc_data *data = mcled_cdev->data;
>> +	struct led_mc_color_entry *priv;
>> +	int i = 0;
>> +
>> +	list_for_each_entry(priv, &data->color_list, list) {
>> +		brightness_val[i] = brightness *
>> +				    priv->intensity / priv->max_intensity;
>> +		i++;
>> +	}
>> +}
>> +EXPORT_SYMBOL_GPL(led_mc_calc_brightness);
>> +
>> +static ssize_t intensity_store(struct device *dev,
>> +				struct device_attribute *intensity_attr,
>> +				const char *buf, size_t size)
>> +{
>> +	struct led_mc_color_entry *priv = container_of(intensity_attr,
>> +						    struct led_mc_color_entry,
>> +						      intensity_attr);
>> +	struct led_classdev_mc_data *data = priv->mcled_cdev->data;
>> +	struct led_classdev_mc *mcled_cdev = data->mcled_cdev;
>> +	struct led_classdev *led_cdev = priv->mcled_cdev->led_cdev;
>> +	unsigned long value;
>> +	ssize_t ret;
>> +
>> +	mutex_lock(&led_cdev->led_access);
>> +
>> +	ret = kstrtoul(buf, 10, &value);
>> +	if (ret)
>> +		goto unlock;
>> +
>> +	if (value > priv->max_intensity) {
>> +		ret = -EINVAL;
>> +		goto unlock;
>> +	}
>> +
>> +	priv->intensity = value;
>> +
>> +	if (mcled_cdev->set_color_brightness) {
> We will not have this, as discussed.

Ack this will be removed in v9


>
>> +		ret = mcled_cdev->set_color_brightness(mcled_cdev,
>> +						       priv->led_color_id,
>> +						       priv->intensity);
>> +		if (ret)
>> +			goto unlock;
>> +	}
>> +
>> +	ret = size;
>> +
>> +unlock:
>> +	mutex_unlock(&led_cdev->led_access);
>> +	return ret;
>> +}
>> +
>> +static ssize_t intensity_show(struct device *dev,
>> +			      struct device_attribute *intensity_attr,
>> +			      char *buf)
>> +{
>> +	struct led_mc_color_entry *priv = container_of(intensity_attr,
>> +						    struct led_mc_color_entry,
>> +						      intensity_attr);
>> +
>> +	return sprintf(buf, "%d\n", priv->intensity);
>> +}
>> +
>> +static ssize_t max_intensity_show(struct device *dev,
>> +				   struct device_attribute *max_intensity_attr,
>> +				   char *buf)
>> +{
>> +	struct led_mc_color_entry *priv = container_of(max_intensity_attr,
>> +						    struct led_mc_color_entry,
>> +						      max_intensity_attr);
>> +
>> +	return sprintf(buf, "%d\n", priv->max_intensity);
>> +}
>> +
>> +static struct attribute *led_color_attrs[] = {
>> +	NULL,
>> +};
>> +
>> +static struct attribute_group led_color_group = {
>> +	.name = "colors",
>> +	.attrs = led_color_attrs,
>> +};
>> +
>> +static int led_multicolor_init_color(struct led_classdev_mc_data *data,
>> +				     struct led_classdev_mc *mcled_cdev,
>> +				     int color_id, int color_index)
>> +{
>> +	struct led_classdev *led_cdev = mcled_cdev->led_cdev;
>> +	struct led_mc_color_entry *mc_priv;
>> +	char *intensity_file_name;
>> +	char *max_intensity_file_name;
>> +	size_t len;
>> +	int ret;
>> +
>> +	mc_priv = devm_kzalloc(led_cdev->dev, sizeof(*mc_priv), GFP_KERNEL);
>> +	if (!mc_priv)
>> +		return -ENOMEM;
>> +
>> +	mc_priv->led_color_id = color_id;
>> +	mc_priv->mcled_cdev = mcled_cdev;
>> +
>> +	sysfs_attr_init(&mc_priv->intensity_attr.attr);
>> +	len = strlen(led_colors[color_id]) + strlen(INTENSITY_NAME) + 1;
>> +	intensity_file_name = kzalloc(len, GFP_KERNEL);
>> +	if (!intensity_file_name) {
>> +		ret = -ENOMEM;
>> +		goto err_out;
> Just return -ENOMEM. No need for err_out label.

Ack


>
>> +	}
>> +
>> +	snprintf(intensity_file_name, len, "%s%s",
>> +		 led_colors[color_id], INTENSITY_NAME);
>> +	mc_priv->intensity_attr.attr.name = intensity_file_name;
>> +	mc_priv->intensity_attr.attr.mode = 644;
>> +	mc_priv->intensity_attr.store = intensity_store;
>> +	mc_priv->intensity_attr.show = intensity_show;
>> +	ret = sysfs_add_file_to_group(&led_cdev->dev->kobj,
>> +				      &mc_priv->intensity_attr.attr,
>> +				      led_color_group.name);
>> +	if (ret)
>> +		goto intensity_err_out;
>> +
>> +	sysfs_attr_init(&mc_priv->max_intensity_attr.attr);
>> +	len = strlen(led_colors[color_id]) + strlen(MAX_INTENSITY_NAME) + 1;
>> +	max_intensity_file_name = kzalloc(len, GFP_KERNEL);
>> +	if (!max_intensity_file_name) {
>> +		ret = -ENOMEM;
>> +		goto intensity_err_out;
>> +	}
>> +
>> +	snprintf(max_intensity_file_name, len, "%s%s",
>> +		 led_colors[color_id], MAX_INTENSITY_NAME);
>> +	mc_priv->max_intensity_attr.attr.name = max_intensity_file_name;
>> +	mc_priv->max_intensity_attr.attr.mode = 444;
>> +	mc_priv->max_intensity_attr.show = max_intensity_show;
>> +	ret = sysfs_add_file_to_group(&led_cdev->dev->kobj,
>> +				      &mc_priv->max_intensity_attr.attr,
>> +				      led_color_group.name);
>> +	if (ret)
>> +		goto max_intensity_err_out;
>> +
>> +	mc_priv->max_intensity = LED_FULL;
>> +	list_add_tail(&mc_priv->list, &data->color_list);
>> +
>> +max_intensity_err_out:
>> +	kfree(max_intensity_file_name);
>> +intensity_err_out:
>> +	kfree(intensity_file_name);
>> +err_out:
>> +	return ret;
>> +}
>> +
>> +static int led_multicolor_init_color_dir(struct led_classdev_mc_data *data,
>> +					 struct led_classdev_mc *mcled_cdev)
>> +{
>> +	struct led_classdev *led_cdev = mcled_cdev->led_cdev;
>> +	u32 color_id;
>> +	int ret;
>> +	int i, j = 0;
>> +
>> +	data->mcled_cdev = mcled_cdev;
>> +
>> +	ret = sysfs_create_group(&led_cdev->dev->kobj, &led_color_group);
>> +	if (ret)
>> +		return ret;
>> +
>> +	for (i = 0; i < LED_COLOR_ID_MAX; i++) {
>> +		color_id = (mcled_cdev->available_colors & (1 << i));
> This is nitpicking but for me it would look cleaner if we had
> color_mask variable:
>
> color_id = (mcled_cdev->available_colors & color_mask);
>
>> +		if (color_id) {
>> +			ret = led_multicolor_init_color(data, mcled_cdev, i, j);
>> +			if (ret)
>> +				break;
>> +
>> +			j++;
>> +		}
> And do the shifting here:
>
> 		color_mask <<= 1;

Ack but responded to your follow up email on using bit ops.


>
>> +	}
>> +
>> +	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_classdev_mc_data *data;
>> +	int ret;
>> +
>> +	if (!mcled_cdev)
>> +		return -EINVAL;
>> +
>> +	data = kzalloc(sizeof(*data), GFP_KERNEL);
>> +	if (!data)
>> +		return -ENOMEM;
>> +
>> +	mcled_cdev->data = data;
>> +	led_cdev = mcled_cdev->led_cdev;
>> +	INIT_LIST_HEAD(&data->color_list);
>> +
>> +	/* Register led class device */
>> +	ret = led_classdev_register_ext(parent, led_cdev, init_data);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return led_multicolor_init_color_dir(data, mcled_cdev);
>> +}
>> +EXPORT_SYMBOL_GPL(led_classdev_multicolor_register_ext);
>> +
>> +void led_classdev_multicolor_unregister(struct led_classdev_mc *mcled_cdev)
>> +{
>> +	if (!mcled_cdev)
>> +		return;
>> +
>> +	sysfs_remove_group(&mcled_cdev->led_cdev->dev->kobj, &led_color_group);
>> +	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.
>> + */
> Let's move documentation to the header. We should to the same with
> the existing led-class.c API one day.

Well this will go away if we remove the non-ext function.

And this documentation needs to be updated anyway.


>> +int devm_led_classdev_multicolor_register(struct device *parent,
>> +					  struct led_classdev_mc *mcled_cdev)
> We don't need non-ext version for a new API.

So we only need the ext version like in the flash class?


>
>> +{
>> +	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@...com>");
>> +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..afcaf429fba5
>> --- /dev/null
>> +++ b/include/linux/led-class-multicolor.h
>> @@ -0,0 +1,76 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/* LED Multicolor class interface
>> + * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
>> + */
>> +
>> +#ifndef __LINUX_MULTICOLOR_LEDS_H_INCLUDED
>> +#define __LINUX_MULTICOLOR_LEDS_H_INCLUDED
>> +
>> +#include <linux/leds.h>
>> +#include <dt-bindings/leds/common.h>
>> +
>> +struct led_classdev_mc;
>> +
>> +struct led_classdev_mc_data {
>> +	struct led_classdev_mc *mcled_cdev;
>> +	struct list_head color_list;
>> +};
>> +
>> +struct led_classdev_mc {
>> +	/* led class device */
>> +	struct led_classdev *led_cdev;
>> +
>> +	/* Set brightness for a specific color id */
>> +	int (*set_color_brightness)(struct led_classdev_mc *mcled_cdev,
>> +				    int color_id, int value);
>> +
>> +	struct led_classdev_mc_data *data;
>> +
>> +	unsigned long available_colors;
>> +	int num_leds;
>> +};
>> +
>> +static inline struct led_classdev_mc *lcdev_to_mccdev(
>> +						struct led_classdev *lcdev)
>> +{
>> +	return container_of(lcdev, struct led_classdev_mc, led_cdev);
>> +}
>> +
>> +/**
>> + * led_classdev_multicolor_register_ext - register a new object of led_classdev
>> + *				      class with support for multicolor LEDs
>> + * @parent: the multicolor LED to register
>> + * @mcled_cdev: the led_classdev_mc structure for this device
>> + * @init_data: the LED class Multi color device initialization data
>> + *
>> + * Returns: 0 on success or negative error value on failure
>> + */
>> +extern int led_classdev_multicolor_register_ext(struct device *parent,
> extern is implied by default for functions. We need also to do this
> cleanup in leds.h soem day.

For clarity we can remove extern from all the APIs in the header?


Dan


>> +					    struct led_classdev_mc *mcled_cdev,
>> +					    struct led_init_data *init_data);
>> +
>> +#define led_classdev_multicolor_register(parent, mcled_cdev)		\
>> +	led_classdev_multicolor_register_ext(parent, mcled_cdev, NULL)
>> +
>> +/**
>> + * led_classdev_multicolor_unregister - unregisters an object of led_classdev
>> + *					class with support for multicolor LEDs
>> + * @mcled_cdev: the multicolor LED to unregister
>> + *
>> + * Unregister a previously registered via led_classdev_multicolor_register
>> + * object
>> + */
>> +extern void led_classdev_multicolor_unregister(struct led_classdev_mc *mcled_cdev);
>> +
>> +extern int devm_led_classdev_multicolor_register(struct device *parent,
>> +					struct led_classdev_mc *mcled_cdev);
>> +
>> +extern void devm_led_classdev_multicolor_unregister(struct device *parent,
>> +					   struct led_classdev_mc *mcled_cdev);
>> +
>> +/* Set brightness for the monochrome LED cluster */
>> +extern void led_mc_calc_brightness(struct led_classdev_mc *mcled_cdev,
>> +			    enum led_brightness brightness,
>> +			    int brightness_val[]);
>> +
>> +#endif	/* __LINUX_MULTICOLOR_LEDS_H_INCLUDED */
>>

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