Re: [PATCH v2] leds: lm3697: Rename struct into more appropriate name

[Dan Murphy]

Pavel

On 10/10/20 4:50 PM, Marek Behun wrote:
> On Sat, 10 Oct 2020 20:57:00 +0200
> Pavel Machek <pavel@xxxxxx> wrote:
>
> > On Fri 2020-10-09 15:51:35, Gabriel David wrote:
> > > The mentioned struct, lm3697_led, was renamed to lm3697_bank since the
> > > structure is representing the control banks. This name, in my opinion,
> > > is more semantically correct. The pointers referring to it were also
> > > renamed.
> > > Signed-off-by: Gabriel David <ultracoolguy4@xxxxxxxxxxxxxx>
> > > ---
> > > Yes, this is the same Gabriel David from ultracoolguy@xxxxxxxxxxxx and
> > > ultracoolguy@xxxxxxxxxxx. If you want me to confirm it I'll gladly do
> > > it.
> > No problem with that, and no need to resend. This can proably wait
> > for 5.11...
> >
> > I'd like some comment from Dan... and perhaps I'd want to understand
> > what the difference between LED and bank is.
> >
> > ...there can be more than one LED connected to the given bank, that's
> > what you are pointing out?
> >
> > ...but these LEDs will always work in unison, and they are handled as
> > single LED by Linux, right?
> Pavel,
>
> the controller can connect 3 LED strips (to 3 different pins on the
> chip). There are 2 LED control banks (this is where you can set
> brightness). For each LED strip (each output pin) you can configure to
> which control bank it connects. So you have 3 LED strips and 2 control
> banks, that is 2^3 = 8 different configurations of connecting LED
> control bank to LED strip.
>
>  From the perspective of Linux you see the two control banks as 2 LED
> class devices (because you are setting brightness for control banks,
> not for the LED strips).

The way Marek explains it is correct and the way I wrote the driver 
intially.  There is no direct control of the LEDs only controlling the 2 
banks.

As an example a device can put LED string 1 and 2 on a single bank to 
control the backlight for a display and put LED string 3 on a different 
bank to control the backlight of a keyboard. Like in the Droid and Droid 
4 devices.  2 strings illuminate the display backlight and 1 string 
illuminates the keyboard the display backlight can have a independent 
brightness then the keyboard.

To me the name of the structure does not impose any functional changes 
just semantic changes.  And it just makes it a bit more difficult to 
back port functional fixes as this patch would be made mandatory for 
cherry picking.  But I do not get many requests to back port this driver 
so it maybe be a moot point.

Dan