Eric, thank you very much for the answer (I have compiled kernel 3.0.35_1.1.0 by the way, but the code hasn't changed since then). I do have a question (in my limited kernel knowledge) :) https://github.com/boundarydevices/linux-imx6/blob/boundary-imx_3.0.35_4.0.0/drivers/i2c/busses/i2c-imx.c#L63
this looks like a module, but as I see in my sabrelite's /lib/modules/3.0.35-1.1.0+g2dc5560 modules.builtin:92:kernel/drivers/i2c/busses/i2c-imx.ko it is built in the kernel. What is the purpose of i2c-imx and how does it relate to imx* boards? Thank you for your help! > Date: Tue, 13 Aug 2013 11:30:00 -0700 > From: [email protected] > To: [email protected] > CC: [email protected] > Subject: Re: [meta-freescale] speed of /dev/i2c-2 in imx6q sabre-lite > > Hi Thanassis, > > On 08/13/2013 11:03 AM, Thanassis Silis wrote: > > Hello everyone, > > I am unaware as to who sets clock speed on the i2c bus and specifically > > on the /dev/i2c-2 which is exposed on the board so as to drive external > > equipment. > > > > I am looking into the linux-boundary kernel files in yocto (dylan) build > > dir, but I cannot figure out where that is set. > > To be honest I don't even know if i'll find that info there, but it > > seems like the right place to start (after googling about it of course). > > > > So who determined the speed (standard mode, fast mode, etc) for the > > external i2c? if it is a driver , which one should I be looking for? > > > > This structure defines the speed of the I2C bus: > > https://github.com/boundarydevices/linux-imx6/blob/boundary-imx_3.0.35_4.0.0/arch/arm/mach-mx6/board-mx6_nitrogen6x.c#L434 > > To change it for i2c-2 by itself, you'll need to make a copy of > that, change the speed value and pass the copy to the routine > imx6q_add_imx_i2c(): > > https://github.com/boundarydevices/linux-imx6/blob/boundary-imx_3.0.35_4.0.0/arch/arm/mach-mx6/board-mx6_nitrogen6x.c#L1320 > > > The reason is I am trying to drive some TMC222 low-power stepper motor > > control ICs, but they do not respond. > > Note I have successfully connected a number of other i2c ICs (among > > others the pca9505x). > > > > An answer is not necessary. Any pointers as to how to go about it , so I > > can learn about this is more than welcome. > > Thank you for your help. > > > > This should be straightforward. > > Let me know if you have any trouble. > > Regards, > > > Eric > >
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