linux-kernel - Re: [PATCH v6 2/2] leds: lm3601x: Introduce the lm3601x LED driver

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Message-ID: <f155e9da-e41d-1201-a9f9-c321654be42e@ti.com>
Date:   Wed, 16 May 2018 16:17:15 -0500
From:   Dan Murphy <dmurphy@...com>
To:     Jacek Anaszewski <jacek.anaszewski@...il.com>,
        Andy Shevchenko <andy.shevchenko@...il.com>
CC:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Pavel Machek <pavel@....cz>,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux LED Subsystem <linux-leds@...r.kernel.org>
Subject: Re: [PATCH v6 2/2] leds: lm3601x: Introduce the lm3601x LED driver

Jacek and Andy

On 05/16/2018 04:13 PM, Dan Murphy wrote:
> Jacek and Andy
> 
> On 05/16/2018 04:02 PM, Jacek Anaszewski wrote:
>> Hi Andy and Dan,
>>
> 
> I will make all the changes then.  I don't want to go through and ack each one.
> 

Let me clarify. I will make all the change Jacek has guided on.  There is still a
terminator comma vs no comma comment that needs disposition at the end of this file.

Dan

> Thanks for the guidance and the reviews.
> 
> It will take a couple days to find all the comments and get this all fixed up.
> 
> Dan
> 
>> On 05/16/2018 12:24 AM, Andy Shevchenko wrote:
>>> On Wed, May 16, 2018 at 1:08 AM, Dan Murphy <dmurphy@...com> wrote:
>>>> On 05/15/2018 04:56 PM, Andy Shevchenko wrote:
>>>>> On Tue, May 15, 2018 at 6:43 PM, Dan Murphy <dmurphy@...com> wrote:
>>>
>>>>>> +       depends on LEDS_CLASS && I2C && OF
>>>>>
>>>>> What is OF specific in this driver?
>>>>
>>>> as3645a_led_class_setup has a "of" dependency
>>>
>>> So what? Is it called from this driver or?
>>>
>>>
>>>>>> +static const struct lm3601x_max_timeouts strobe_timeouts[] = {
>>>>>> +       { 40000, 0x00 },
>>>>>> +       { 80000, 0x01 },
>>>>>> +       { 120000, 0x02 },
>>>>>> +       { 160000, 0x03 },
>>>>>> +       { 200000, 0x04 },
>>>>>> +       { 240000, 0x05 },
>>>>>> +       { 280000, 0x06 },
>>>>>> +       { 320000, 0x07 },
>>>>>> +       { 360000, 0x08 },
>>>>>> +       { 400000, 0x09 },
>>>>>> +       { 600000, 0x0a },
>>>>>> +       { 800000, 0x0b },
>>>>>> +       { 1000000, 0x0c },
>>>>>> +       { 1200000, 0x0d },
>>>>>> +       { 1400000, 0x0e },
>>>>>> +       { 1600000, 0x0f },
>>>>>
>>>>> Huh?!
>>>>
>>>> Please give comments that actually mean something other wise I will opt to ignore them.
>>>
>>> I did below.
>>>
>>>>> strobe_timeout = (x + 1) * 40 * MSECS_IN_SEC;
>>>>
>>>> Not sure what equation you are trying to point out here.  But if you are trying to apply
>>>> a timeout step you cannot do this with this part.  As pointed out in the DT doc the timeout
>>>> step is not linear.
>>>
>>> Yeah, I know people are more than often too lazy to think.
>>>
>>> if (x < 9)
>>>   strobe_timeout = (x + 1) * 40 * MSECS_IN_SEC;
>>> else
>>>   strobe_timeout = (400 + (x - 9) * 200) * MSECS_IN_SEC;
>>>
>>
>> I like the idea.
>>
>>>>>> +               brightness_val = (brightness/2);
>>>>>
>>>>> Spaces.
>>>>
>>>> Not sure what this means checkpatch was clean
>>>
>>> Even besides missed whispaces it has redundant parens.
>>>
>>> checkpatch is not a silver bullet to get your code clean and nice.
>>>
>>>>> This is return led_...();
>>>>
>>>> That is a preference.  It does not have to be that way.
>>
>> I missed that. Dan, please follow Andy's advise.
>>
>>>
>>> What do you mean? We do not appreciate +LOCs for no (or even nagative!) benefit.
>>>
>>>>>> +               ret = of_property_read_string(led->led_node, "label", &name);
>>>>>
>>>>> device_property_...();
>>>>
>>>> It can be if the maintainer is requesting this.
>>>
>>> Jacek, if you need rationale behind this comment it's here: the driver
>>> has nothing DT specific and getting rid of OF centric programming
>>> allows to reuse the driver on non-DT platforms w/o touching a source
>>> code.
>>
>> It has an added value, so yes, let's use it as a standard approach
>> from now on.
>>
>>>> Is the trend to move to these functions?
>>>
>>> See above.
>>>
>>>> Most drivers use the "of" calls.
>>>
>>> So what?
>>>
>>>
>>>>>> +               if (!ret)
>>>>>
>>>>> if (ret) sounds more natural. And better just to split
>>>>>
>>>>>> +                       snprintf(led->led_name, sizeof(led->led_name),
>>>>>> +                               "%s:%s", led->led_node->name, name);
>>>>>> +               else
>>>>>> +                       snprintf(led->led_name, sizeof(led->led_name),
>>>>>> +                               "%s:torch", led->led_node->name);
>>>>>
>>>>> const char *tmp;
>>>>>
>>>>> ret = device_property_read_...(&tmp);
>>>>> if (ret)
>>>>>   tmp = ...
>>>>> sprintf(...);
>>
>> We're no longer taking devicename section of a LED class device name
>> from DT, so it will look differently anyway.
>>
>>> No comments on this?
>>>
>>>>>> +       led = devm_kzalloc(&client->dev,
>>>>>> +                           sizeof(struct lm3601x_led), GFP_KERNEL);
>>>>>
>>>>> sizeof(*led) and one line in the result
>>>
>>> And this?
>>
>> Ack.
>>
>>>
>>>>>> +       { },
>>>>>
>>>>> Terminators better w/o comma.
>>>>
>>>> Looking at other drivers adding comma's on the sentinel is accepted.  See the as3645a driver
>>>
>>> So what?
>>>
>>> Terminator at compile time even better.
>>>
>>>>>> +       {},
>>>>>
>>>>> Ditto.
>>>>
>>>> See above
>>>
>>> See above.
>>>
>>
> 
> 


-- 
------------------
Dan Murphy