Re: [PATCH] i2c: Raise SDA for each received bit, if necessary

From	Wolfram Sang <wsa@the-dreams.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH] i2c: Raise SDA for each received bit, if necessary
Date	2016-05-12 11:10 +0200
Message-ID	<rxUN4-2vc-3@gated-at.bofh.it> (permalink)
References	<rsCe7-5LS-27@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

[Multipart message — attachments visible in raw view] - view raw

Hi Thomas,

On Wed, Apr 27, 2016 at 08:11:54PM +0200, Thomas Zimmermann wrote:
> Some I2C adapters don't raise SDA by themselves when sending a bit. This
> behavior can be seen with the DDC channel of SiS 300 graphics cards.

I think you mean 'clients' or 'devices' here, not adapters (masters),
right? So, it seems you have a bus without a pull-up resistor (or a
broken one?) but use now a push-pull design. This is against the I2C
standard and for most circiuts quite dangerous as it can lead to
shortcuts.

Do you have any hints that the bus is designed this way? In which driver
do you want to use the new flag?

Thanks,

   Wolfram

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

Re: [PATCH] i2c: Raise SDA for each received bit, if necessary Wolfram Sang <wsa@the-dreams.de> - 2016-05-12 11:10 +0200
  Re: [PATCH] i2c: Raise SDA for each received bit, if necessary Thomas Zimmermann <tdz@users.sourceforge.net> - 2016-05-12 18:20 +0200
    Re: [PATCH] i2c: Raise SDA for each received bit, if necessary Wolfram Sang <wsa@the-dreams.de> - 2016-05-13 12:40 +0200
      Re: [PATCH] i2c: Raise SDA for each received bit, if necessary Thomas Zimmermann <tdz@users.sourceforge.net> - 2016-05-13 18:10 +0200

csiph-web