lkml.org 
[lkml]   [2021]   [Mar]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v3 2/4] leds: simatic-ipc-leds: add new driver for Siemens Industial PCs
On Tue, Mar 30, 2021 at 3:35 PM Henning Schild
<henning.schild@siemens.com> wrote:
> Am Tue, 30 Mar 2021 15:15:16 +0300
> schrieb Andy Shevchenko <andy.shevchenko@gmail.com>:
> > On Tue, Mar 30, 2021 at 2:58 PM Henning Schild
> > <henning.schild@siemens.com> wrote:
> > > Am Tue, 30 Mar 2021 14:04:35 +0300
> > > schrieb Andy Shevchenko <andy.shevchenko@gmail.com>:
> > > > On Mon, Mar 29, 2021 at 8:59 PM Henning Schild
> > > > <henning.schild@siemens.com> wrote:

> > > > > +static struct simatic_ipc_led simatic_ipc_leds_mem[] = {
> > > > > + {0x500 + 0x1A0, "red:" LED_FUNCTION_STATUS "-1"},
> > > > > + {0x500 + 0x1A8, "green:" LED_FUNCTION_STATUS "-1"},
> > > > > + {0x500 + 0x1C8, "red:" LED_FUNCTION_STATUS "-2"},
> > > > > + {0x500 + 0x1D0, "green:" LED_FUNCTION_STATUS "-2"},
> > > > > + {0x500 + 0x1E0, "red:" LED_FUNCTION_STATUS "-3"},
> > > > > + {0x500 + 0x198, "green:" LED_FUNCTION_STATUS "-3"},
> > > > > + { }
> > > > > +};
> > > >
> > > > It seems to me like poking GPIO controller registers directly.
> > > > This is not good. The question still remains: Can we simply
> > > > register a GPIO (pin control) driver and use an LED GPIO driver
> > > > with an additional board file that instantiates it?
> > >
> > > I wrote about that in reply to the cover letter. My view is still
> > > that it would be an abstraction with only one user, just causing
> > > work and likely not ending up as generic as it might eventually
> > > have to be.
> > >
> > > The region is reserved, not sure what the problem with the "poking"
> > > is.
> >
> >
> > > Maybe i do not understand all the benefits of such a split at this
> > > point in time. At the moment i only see work with hardly any
> > > benefit, not just work for me but also for maintainers. I sure do
> > > not mean to be ignorant. Maybe you go into details and convince me
> > > or we wait for other peoples opinions on how to proceed, maybe
> > > there is a second user that i am not aware of?
> > > Until i am convinced otherwise i will try to argue that a
> > > single-user-abstraction is needless work/code, and should be done
> > > only when actually needed.
> >
> > I have just read your messages (there is a cover letter and additional
> > email which was sent lately).
> >
> > I would like to know what the CPU model number on that board is. Than
> > we can continue to see what possibilities we have here.
>
> I guess we are talking about the one that uses memory mapped, that is
> called an "IPC127E" and seems to have either Intel Atom E3940 or E3930
> which seems to be Apollo Lake.

Yep. And now the question, in my patch series you should have got the
apollolake-pinctrl driver loaded (if not, we have to investigate why
it's not being instantiated). This will give you a read GPIO driver.
So, you may use regular LED GPIO on top of it
(https://elixir.bootlin.com/linux/latest/source/drivers/leds/leds-gpio.c).
I would like to understand why it can't be achieved.

--
With Best Regards,
Andy Shevchenko

\
 
 \ /
  Last update: 2021-03-30 14:43    [W:0.126 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site