Messages in this thread | | | From | "Voss, Nikolaus" <> | Date | Wed, 2 Nov 2011 06:56:50 +0100 | Subject | RE: [PATCH] i2c-gpio.c: correct logic of pdata->scl_is_open_drain |
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> 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
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