On 04/16/2013 03:36 AM, Wolfram Sang wrote: > Doug, > > On Tue, Apr 09, 2013 at 02:34:28PM -0700, Doug Anderson wrote: >> The i2c-arb-gpio-challenge driver implements an I2C arbitration scheme >> where masters need to claim the bus with a GPIO before they can start >> a transcation. This should generally only be used when standard I2C >> multimaster isn't appropriate for some reason (errata/bugs). >> >> This driver is based on code that Simon Glass added to the i2c-s3c2410 >> driver in the Chrome OS kernel 3.4 tree. The current incarnation as a >> mux driver is as suggested by Grant Likely. See >> <https://patchwork.kernel.org/patch/1877311/> for some history. >> diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt >> +GPIO-based I2C Arbitration >> +========================== >> +This uses GPIO lines to arbitrate who is the master of an I2C bus in a >> +multimaster situation. > > "uses GPIO lines and a challange & response mechanism" or something like > that. There might be other GPIO based arbitrations in the future (though > I hope there won't). The existing text appears clearer to me; this document should spell out the exact details of the protocol in later paragraphs, so there's no need to try and spell it out here. >> +- their-claim-gpios: The GPIOs that the other sides use the claim the bus. >> + Note that some implementations may only support a single other master. > > Stronger? "Currently, only one other master is supported"? The DT binding documentation, which should be OS-/driver-agnostic, should describe the binding, not the implementation. The limitation that Linux imposes is OS-specific and hence should not be mentioned here as an absolute, or perhaps even at all. -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
