All of lore.kernel.org
 help / color / mirror / Atom feed
From: Martin Peres <martin.peres-GANU6spQydw@public.gmane.org>
To: gpu-public-documentation
	<gpu-public-documentation-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Cc: nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
Subject: PWM-based voltage management input clock
Date: Fri, 18 Sep 2015 23:13:53 +0300	[thread overview]
Message-ID: <55FC7081.7050007@free.fr> (raw)

Hello,

We recently reverse engineered PWM-based voltage management but found an 
odity in the input clock frequency for the PWM controller. It seems like 
RM is assuming an input clock of 27.648 MHz instead of the actual 27MHz 
crystal found on the board.

I thus have the following questions:
  - Is it a fixed value hardcoded in RM? (Current way it is done in Nouveau)
  - Should we use crystal_MHz * 1.024?

I could spend some time hooking up my osciloscope to the VR to check if 
it is a bringup issue but it would not help Nouveau much as we need to 
reproduce the behaviour of RM anyway since this is the only validated 
configuration.

Thanks in advance,
Martin

PS: The registers for this PWM controller are 0x20340 and 0x20344.
_______________________________________________
Nouveau mailing list
Nouveau@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/nouveau

             reply	other threads:[~2015-09-18 20:13 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-18 20:13 Martin Peres [this message]
     [not found] ` <55FC7081.7050007-GANU6spQydw@public.gmane.org>
2015-09-18 20:30   ` PWM-based voltage management input clock Andy Ritger
     [not found]     ` <20150918203051.GA23395-FqhoBIChHNk6p33qAC56yVaTQe2KTcn/@public.gmane.org>
2015-09-19 16:21       ` Martin Peres
     [not found]         ` <55FD8B70.6010704-GANU6spQydw@public.gmane.org>
2015-10-26 23:47           ` Martin Peres

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=55FC7081.7050007@free.fr \
    --to=martin.peres-ganu6spqydw@public.gmane.org \
    --cc=gpu-public-documentation-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org \
    --cc=nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.