Messages in this thread | | | Date | Fri, 16 Jul 2021 09:51:46 +0200 | From | Miquel Raynal <> | Subject | Re: [PATCH 0/4] i3c: master: svc: some bug fixes |
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Hi Clark,
Clark Wang <xiaoning.wang@nxp.com> wrote on Thu, 15 Jul 2021 16:24:09 +0800:
> Hi, > > I am using SVC I3C module recently. I fix some problems and also have a > question. > > My question is: > Can I3C bus support pure I2C mode in kernel? > Or in other words, in mixed mode, must there be at least one I3C device on > the I3C bus? > > The pure I3C mode works fine. But when only have one I2C device on the > I3C bus, the probe in function i3c_master_bus_init() will go error. Because > there is no one on I3C bus can ACK the I3C message with I3C message speed. Then > it will return error at function i3c_master_rstdaa_locked() because of no ACK > for 0x7e start byte. > When I use the following dtb configuration, the above problem occurs. > &i3c2 { > #address-cells = <3>; > #size-cells = <0>; > pinctrl-names = "default"; > pinctrl-0 = <&pinctrl_i3c2>; > i2c-scl-hz = <400000>; > status = "okay"; > > lsm6dso_i2c: imu@6a { > compatible = "st,lsm6dso"; > reg = <0x6a 0x0 0x50>; > }; > }; > > But I saw a similar configuration example in > /home/nxf47749/work/kernel/i3c/Documentation/devicetree/bindings/i3c/snps,dw-i3c-master.txt. > I wonder if that can work normally? > > I know the definition in the specification is: > Mixed xxx Bus: I3C Bus topology with both I2C and I3C Devices present > on the I3C Bus... > But I think it is feasible to use pure I2C mode with I3C module. > I am not sure why the use of pure I2C mode is restricted in the software. > > If there are errors in my ideas, please correct me in time. Thank you all.
As you pointed out, I am not aware of a specific I2C only bus setting but if you find a way to workaround the issue raised above by software in a rather clean way, then... why not?
> Here are the fixes. > > Clark Wang (4): > i3c: master: svc: move module reset behind clk enable > i3c: master: svc: fix atomic issue > i3c: master: svc: add support for slave to stop returning data > i3c: master: svc: set ODSTOP to let I2C device see the STOP signal > > drivers/i3c/master/svc-i3c-master.c | 45 +++++++++++++++++++---------- > 1 file changed, 30 insertions(+), 15 deletions(-) >
Thanks, Miquèl
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