Re: [PATCH v8 6/9] leds: multicolor: Introduce a multicolor class definition

[Jacek Anaszewski]

Dan,

On 9/23/19 5:14 PM, Dan Murphy wrote:
> 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.
> 
[...]
>>> +static int led_multicolor_init_color_dir(struct led_classdev_mc_data
>>> *data,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct led_classdev_mc *mcled_cdev)
>>> +{
>>> +ÂÂÂ struct led_classdev *led_cdev = mcled_cdev->led_cdev;
>>> +ÂÂÂ u32 color_id;
>>> +ÂÂÂ int ret;
>>> +ÂÂÂ int i, j = 0;
>>> +
>>> +ÂÂÂ data->mcled_cdev = mcled_cdev;
>>> +
>>> +ÂÂÂ ret = sysfs_create_group(&led_cdev->dev->kobj, &led_color_group);
>>> +ÂÂÂ if (ret)
>>> +ÂÂÂÂÂÂÂ return ret;
>>> +
>>> +ÂÂÂ for (i = 0; i < LED_COLOR_ID_MAX; i++) {
>>> +ÂÂÂÂÂÂÂ 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);
>>
>>> +ÂÂÂÂÂÂÂ if (color_id) {
>>> +ÂÂÂÂÂÂÂÂÂÂÂ ret = led_multicolor_init_color(data, mcled_cdev, i, j);
>>> +ÂÂÂÂÂÂÂÂÂÂÂ if (ret)
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ break;
>>> +
>>> +ÂÂÂÂÂÂÂÂÂÂÂ j++;
>>> +ÂÂÂÂÂÂÂ }
>> And do the shifting here:
>>
>> ÂÂÂÂÂÂÂ color_mask <<= 1;
> 
> Ack but responded to your follow up email on using bit ops.

Yeah, bitops will be better here.

>>> +ÂÂÂ }
>>> +
>>> +ÂÂÂ return ret;
>>> +}
>>> +
>>> +int led_classdev_multicolor_register_ext(struct device *parent,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct led_classdev_mc *mcled_cdev,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct led_init_data *init_data)
>>> +{
>>> +ÂÂÂ struct led_classdev *led_cdev;
>>> +ÂÂÂ struct led_classdev_mc_data *data;
>>> +ÂÂÂ int ret;
>>> +
>>> +ÂÂÂ if (!mcled_cdev)
>>> +ÂÂÂÂÂÂÂ return -EINVAL;
>>> +
>>> +ÂÂÂ data = kzalloc(sizeof(*data), GFP_KERNEL);
>>> +ÂÂÂ if (!data)
>>> +ÂÂÂÂÂÂÂ return -ENOMEM;
>>> +
>>> +ÂÂÂ mcled_cdev->data = data;
>>> +ÂÂÂ led_cdev = mcled_cdev->led_cdev;
>>> +ÂÂÂ INIT_LIST_HEAD(&data->color_list);
>>> +
>>> +ÂÂÂ /* Register led class device */
>>> +ÂÂÂ ret = led_classdev_register_ext(parent, led_cdev, init_data);
>>> +ÂÂÂ if (ret)
>>> +ÂÂÂÂÂÂÂ return ret;
>>> +
>>> +ÂÂÂ 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)
>>> +{
>>> +ÂÂÂ if (!mcled_cdev)
>>> +ÂÂÂÂÂÂÂ return;
>>> +
>>> +ÂÂÂ sysfs_remove_group(&mcled_cdev->led_cdev->dev->kobj,
>>> &led_color_group);
>>> +ÂÂÂ 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)
>>> +{
>>> +ÂÂÂ 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,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 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?

Yes. We can always fallback to the old LED name initialization way
that uses struct led_classdev's name property by setting init_data
to NULL.

>>> +{
>>> +ÂÂÂ struct led_classdev_mc **dr;
>>> +ÂÂÂ int ret;
>>> +
>>> +ÂÂÂ dr = devres_alloc(devm_led_classdev_multicolor_release,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂ sizeof(*dr), GFP_KERNEL);
>>> +ÂÂÂ if (!dr)
>>> +ÂÂÂÂÂÂÂ return -ENOMEM;
>>> +
>>> +ÂÂÂ ret = led_classdev_multicolor_register(parent, mcled_cdev);
>>> +ÂÂÂ if (ret) {
>>> +ÂÂÂÂÂÂÂ devres_free(dr);
>>> +ÂÂÂÂÂÂÂ return ret;
>>> +ÂÂÂ }
>>> +
>>> +ÂÂÂ *dr = mcled_cdev;
>>> +ÂÂÂ devres_add(parent, dr);
>>> +
>>> +ÂÂÂ return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(devm_led_classdev_multicolor_register);
>>> +
>>> +static int devm_led_classdev_multicolor_match(struct device *dev,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ void *res, void *data)
>>> +{
>>> +ÂÂÂ struct mcled_cdev **p = res;
>>> +
>>> +ÂÂÂ if (WARN_ON(!p || !*p))
>>> +ÂÂÂÂÂÂÂ return 0;
>>> +
>>> +ÂÂÂ return *p == data;
>>> +}
>>> +
>>> +/**
>>> + * devm_led_classdev_multicolor_unregister() - resource managed
>>> + *ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 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,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct led_classdev_mc *mcled_cdev)
>>> +{
>>> +ÂÂÂ WARN_ON(devres_release(dev,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ devm_led_classdev_multicolor_release,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 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..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 {
>>> +ÂÂÂ struct led_classdev_mc *mcled_cdev;
>>> +ÂÂÂ struct list_head color_list;
>>> +};
>>> +
>>> +struct led_classdev_mc {
>>> +ÂÂÂ /* led class device */
>>> +ÂÂÂ struct led_classdev *led_cdev;
>>> +
>>> +ÂÂÂ /* Set brightness for a specific color id */
>>> +ÂÂÂ int (*set_color_brightness)(struct led_classdev_mc *mcled_cdev,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ int color_id, int value);
>>> +
>>> +ÂÂÂ struct led_classdev_mc_data *data;
>>> +
>>> +ÂÂÂ unsigned long available_colors;
>>> +ÂÂÂ int num_leds;
>>> +};
>>> +
>>> +static inline struct led_classdev_mc *lcdev_to_mccdev(
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct led_classdev *lcdev)
>>> +{
>>> +ÂÂÂ return container_of(lcdev, struct led_classdev_mc, led_cdev);
>>> +}
>>> +
>>> +/**
>>> + * led_classdev_multicolor_register_ext - register a new object of
>>> led_classdev
>>> + *ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 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?

Yes, in a dedicated patch.

>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct led_classdev_mc *mcled_cdev,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct led_init_data *init_data);
>>> +
>>> +#define led_classdev_multicolor_register(parent, mcled_cdev)ÂÂÂÂÂÂÂ \
>>> +ÂÂÂ led_classdev_multicolor_register_ext(parent, mcled_cdev, NULL)
>>> +
>>> +/**
>>> + * led_classdev_multicolor_unregister - unregisters an object of
>>> led_classdev
>>> + *ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 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,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct led_classdev_mc *mcled_cdev);
>>> +
>>> +extern void devm_led_classdev_multicolor_unregister(struct device
>>> *parent,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 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,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ enum led_brightness brightness,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ int brightness_val[]);
>>> +
>>> +#endifÂÂÂ /* __LINUX_MULTICOLOR_LEDS_H_INCLUDED */
>>>
> 

-- 
Best regards,
Jacek Anaszewski