patch: make i2c(8) usable for scripting

[Poul-Henning Kamp]

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Ian Lepore writes:

> On Sat, 2021-05-15 at 20:14 +0000, Poul-Henning Kamp wrote:
> > The /dev/iic%d filedescriptor is opened and closed for every single
> > command, in the hope that it will aid multiple separate programs
> > sharing I2C busses.  I have not actually tried that yet, so it may
> > need more work (exclusive opens etc.).
>
> There should be no need to do that.  The i2c bus is arbitrated in
> iicbus/iiconf.c and most all the in-tree drivers now use either
> explicit iicbus_request_bus() calls, or use iicbus_transfer_excl(). 
> Certainly users of iic(4) don't need to be protected from each other;
> everything in the driver that uses the bus does so inside of
> request_bus / release_bus calls.

How does that work when i2c(8) (by default) issues discrete start/stop commands ?

Related to that:  Should i2c(8)'s -m default be changed to 'tr' ?

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Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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