Date: Sat, 15 May 2021 22:05:33 -0600 From: Ian Lepore <ian@freebsd.org> To: Poul-Henning Kamp <phk@phk.freebsd.dk>, hackers@freebsd.org Subject: Re: patch: make i2c(8) usable for scripting Message-ID: <8d232feb354bf404426c51efe4953551ae2476c9.camel@freebsd.org> In-Reply-To: <12056.1621109641@critter.freebsd.dk> References: <12056.1621109641@critter.freebsd.dk>
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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. -- Ian
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