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Subject: Re: [PATCH v8 6/9] leds: multicolor: Introduce a multicolor class
 definition
To:     Dan Murphy <dmurphy@ti.com>, pavel@ucw.cz
Cc:     linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20190920174139.30079-1-dmurphy@ti.com>
 <20190920174139.30079-7-dmurphy@ti.com>
 <157045af-f6c4-919b-3617-350299639f8f@gmail.com>
 <c0499e2e-8595-5224-e13a-1b058695e785@ti.com>
From:   Jacek Anaszewski <jacek.anaszewski@gmail.com>
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Message-ID: <5b3d60a7-4893-0118-1f40-d4b4ad6d279f@gmail.com>
Date:   Mon, 23 Sep 2019 23:36:05 +0200
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In-Reply-To: <c0499e2e-8595-5224-e13a-1b058695e785@ti.com>
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Sender: linux-kernel-owner@vger.kernel.org
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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,
>>> +                     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.

Yeah, bitops will be better here.

>>> +    }
>>> +
>>> +    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?

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.

>>> +{
>>> +    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@ti.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?

Yes, in a dedicated patch.

>>> +                        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 */
>>>
> 

-- 
Best regards,
Jacek Anaszewski