From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Clark Wang <xiaoning.wang@nxp.com>
Cc: conor.culhane@silvaco.com, alexandre.belloni@bootlin.com,
vitor.soares@synopsys.com, boris.brezillon@bootlin.com,
linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/4] i3c: master: svc: some bug fixes
Date: Fri, 16 Jul 2021 09:51:46 +0200 [thread overview]
Message-ID: <20210716095146.2182acb3@xps13> (raw)
In-Reply-To: <20210715082413.3042149-1-xiaoning.wang@nxp.com>
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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next prev parent reply other threads:[~2021-07-16 7:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-15 8:24 [PATCH 0/4] i3c: master: svc: some bug fixes Clark Wang
2021-07-15 8:24 ` [PATCH 1/4] i3c: master: svc: move module reset behind clk enable Clark Wang
2021-07-15 22:51 ` Miquel Raynal
2021-07-15 8:24 ` [PATCH 2/4] i3c: master: svc: fix atomic issue Clark Wang
2021-07-15 22:52 ` Miquel Raynal
2021-07-16 1:58 ` Clark Wang
2021-07-15 8:24 ` [PATCH 3/4] i3c: master: svc: add support for slave to stop returning data Clark Wang
2021-07-15 22:55 ` Miquel Raynal
2021-07-16 1:53 ` Clark Wang
2021-07-15 8:24 ` [PATCH 4/4] i3c: master: svc: set ODSTOP to let I2C device see the STOP signal Clark Wang
2021-07-15 22:57 ` Miquel Raynal
2021-07-16 7:51 ` Miquel Raynal [this message]
2021-07-16 8:07 ` [PATCH 0/4] i3c: master: svc: some bug fixes Clark Wang
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