lkml.org 
[lkml]   [2011]   [Nov]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRE: [PATCH] i2c-gpio.c: correct logic of pdata->scl_is_open_drain
> If the "is_open_drain" flags are not set, the I2C bus works correctly
> regardless of the existence of the pull-ups.

No, I2C can only work with anything pulling up SDA weakly, usually an
external pullup. This is independent of the "is_open_drain" property
which only describes how the driver internally accomplishes the high
impedance state.

SCL can be driven push-pull ("scl_is_output_only") but will not be
I2C-compliant any more (no clock stretching), and only clients not relying
on that feature will work.

Niko



\
 
 \ /
  Last update: 2011-11-02 07:15    [W:0.051 / U:4.788 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site