linux-spi.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
To: "Mike Frysinger" <vapier.adi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Bryan Wu <bryan.wu-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>,
	spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 00/14] Blackfin on-chip SPI controller driver updates and bug-fixing
Date: Tue, 30 Oct 2007 13:42:18 -0700	[thread overview]
Message-ID: <200710301342.18559.david-b@pacbell.net> (raw)
In-Reply-To: <8bd0f97a0710301329i8a21b22ncc9f71a81bc06543-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Tuesday 30 October 2007, Mike Frysinger wrote:
> On 10/30/07, David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org> wrote:
> > And also, pay closer attention to when you may be making
> > changes that make device drivers work differently over
> > your spi_master controller driver than anyone elses ...
> > such platform-specific behaviors are undesirable, and when
> > they go against specified behavior they are also bugs.
> 
> was there something that caught your eye other than the ugly udelay()
> you mentioned in the other thread ?

That one was a feature that might be more generally necessary,
just to meet chip timing specs.  Mostly they're no trouble.
But sometimes there are constraints around chipselect, or at
particular points in a protocol exchange ... as you know, SPI
has no in-band synchronization, so timing delays are about as
good as any standardized infrastructure can get.  So if that
particular timing tweak was essential to make that driver work,
it might be something the API should address -- instead of just
a particular controller.

The other point was the handling of the two spi_transfer protocol
tweaking options.  The comment went against the interface spec.
Now, maybe that was an issue of weak English skills ... but from
my scanning the patch, I got the impression one intent of that
patch really was to do what the comment said.  (Of course it did
a lot of other stuff, which looked less dubious and might have
had a lot more to do with why the patch made that m25p16 chip
behave on that new board.)

- Dave

-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >> http://get.splunk.com/

  parent reply	other threads:[~2007-10-30 20:42 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-30  9:17 [PATCH 00/14] Blackfin on-chip SPI controller driver updates and bug-fixing Bryan Wu
     [not found] ` <1193735885-8202-1-git-send-email-bryan.wu-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>
2007-10-30  9:17   ` [PATCH 01/14] Blackfin SPI driver: Initial supporting BF54x in SPI driver Bryan Wu
2007-10-30  9:17   ` [PATCH 02/14] Blackfin SPI driver: use new GPIO API and add error handling Bryan Wu
2007-10-30  9:17   ` [PATCH 03/14] Blackfin SPI driver: add error handing Bryan Wu
2007-10-30  9:17   ` [PATCH 04/14] Blackfin SPI driver: Blackfin SPI driver does not respect the per-transfer cs_change field Bryan Wu
2007-10-30  9:17   ` [PATCH 05/14] Blackfin SPI driver: prevent people from setting bits in ctl_reg Bryan Wu
2007-10-30  9:17   ` [PATCH 06/14] Blackfin SPI driver: update spi driver to support multi-ports Bryan Wu
2007-10-30  9:17   ` [PATCH 07/14] Blackfin SPI driver: Add SPI master controller platform device 1 Bryan Wu
2007-10-30 19:08     ` David Brownell
     [not found]       ` <200710301208.13367.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2007-10-31  4:18         ` Bryan Wu
2007-10-30  9:17   ` [PATCH 08/14] Blackfin SPI driver: Move GPIO config to setup and cleanup Bryan Wu
2007-10-30  9:18   ` [PATCH 09/14] Blackfin SPI driver: Fix SPI driver to work with SPI flash ST25P16 on bf548 Bryan Wu
2007-10-30 20:05     ` David Brownell
2007-10-31  6:50       ` Bryan Wu
2007-10-31  7:11         ` David Brownell
     [not found]           ` <200710310011.33545.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2007-10-31  7:35             ` Bryan Wu
2007-10-31  8:02               ` David Brownell
     [not found]                 ` <200710310102.36542.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2007-10-31  8:52                   ` Bryan Wu
2007-10-31  8:33             ` Mike Frysinger
     [not found]               ` <8bd0f97a0710310133m7b5cbbf3j545a489c401185df-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2007-10-31 19:01                 ` David Brownell
     [not found]                   ` <200710311201.29643.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2007-10-31 19:16                     ` Mike Frysinger
     [not found]                       ` <8bd0f97a0710311216l25f89b37v356fd44d7c1999da-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2007-10-31 20:14                         ` David Brownell
2007-10-30  9:18   ` [PATCH 10/14] Blackfin SPI driver: Clean up useless wait in bfin SPI driver Bryan Wu
2007-10-30  9:18   ` [PATCH 11/14] Blackfin SPI driver: Move global SPI regs_base and dma_ch to struct driver_data Bryan Wu
2007-10-30  9:18   ` [PATCH 12/14] Blackfin SPI driver: Fix bug in u16_cs_chg_reader to read data_len-2 bytes data firstly, then read out the last 2 bytes data Bryan Wu
2007-10-30  9:18   ` [PATCH 13/14] Blackfin SPI driver: Move cs_chg_udelay to cs_deactive to fix bug when some SPI LCD driver needs delay after cs_deactive Bryan Wu
     [not found]     ` <1193735885-8202-14-git-send-email-bryan.wu-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>
2007-10-30 20:18       ` David Brownell
     [not found]         ` <200710301319.00071.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2007-10-31  6:30           ` Bryan Wu
2007-10-31 19:04             ` Cameron Barfield
2007-10-30  9:18   ` [PATCH 14/14] Blackfin SPI driver: set correct baud for spi mmc and enable SPI after DMA Bryan Wu
2007-10-30 20:24   ` [PATCH 00/14] Blackfin on-chip SPI controller driver updates and bug-fixing David Brownell
     [not found]     ` <200710301324.07691.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2007-10-30 20:29       ` Mike Frysinger
     [not found]         ` <8bd0f97a0710301329i8a21b22ncc9f71a81bc06543-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2007-10-30 20:42           ` David Brownell [this message]
     [not found]             ` <200710301342.18559.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2007-10-30 20:54               ` David Brownell

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=200710301342.18559.david-b@pacbell.net \
    --to=david-b-ybekhbn/0ldr7s880joybq@public.gmane.org \
    --cc=bryan.wu-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org \
    --cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
    --cc=spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org \
    --cc=vapier.adi-Re5JQEeQqe8AvxtiuMwx3w@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).