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SubjectRE: [PATCH 2/3] i3c: add mixed limited bus mode
Date
Hi Boris,

From: Boris Brezillon <boris.brezillon@collabora.com>
Date: Tue, Apr 16, 2019 at 07:00:49

> Hi Vitor,
>
> On Mon, 15 Apr 2019 20:46:42 +0200
> Vitor Soares <vitor.soares@synopsys.com> wrote:
>
> > The i3c bus spec define a bus configuration where the i2c devices
>
> ^defines I2C devices...
>
> > doesn't have the 50ns filter yet they allow the SDR max speed.
>
> ^don't ^ a 50ns filter but support SCL running at SDR max
> rate (12MHz).
>
> >
> > This patch introduce the limited bus mode so the users can use
>
> ^introduces ^ so that users
>
> > a higher speed on presence of i2c devices index 1.
>
> ^in
>
> >
> > Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
> > Cc: Boris Brezillon <bbrezillon@kernel.org>
> > Cc: <linux-kernel@vger.kernel.org>
> > ---
> > drivers/i3c/master.c | 5 +++++
> > include/linux/i3c/master.h | 5 +++++
> > 2 files changed, 10 insertions(+)
> >
> > diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> > index 1c4a86a..46d3774 100644
> > --- a/drivers/i3c/master.c
> > +++ b/drivers/i3c/master.c
> > @@ -463,6 +463,7 @@ static int i3c_bus_init(struct i3c_bus *i3cbus)
> > static const char * const i3c_bus_mode_strings[] = {
> > [I3C_BUS_MODE_PURE] = "pure",
> > [I3C_BUS_MODE_MIXED_FAST] = "mixed-fast",
> > + [I3C_BUS_MODE_MIXED_LIMITED] = "mixed-limited",
> > [I3C_BUS_MODE_MIXED_SLOW] = "mixed-slow",
> > };
> >
> > @@ -575,6 +576,7 @@ int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode,
> > i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
> > break;
> > case I3C_BUS_MODE_MIXED_FAST:
> > + case I3C_BUS_MODE_MIXED_LIMITED:
> > if (!i3cbus->scl_rate.i3c)
> > i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
> > if (!i3cbus->scl_rate.i2c)
> > @@ -2481,6 +2483,9 @@ int i3c_master_register(struct i3c_master_controller *master,
> > mode = I3C_BUS_MODE_MIXED_FAST;
> > break;
> > case I3C_LVR_I2C_INDEX(1):
> > + if (mode < I3C_BUS_MODE_MIXED_LIMITED)
> > + mode = I3C_BUS_MODE_MIXED_LIMITED;
> > + break;
> > case I3C_LVR_I2C_INDEX(2):
> > if (mode < I3C_BUS_MODE_MIXED_SLOW)
> > mode = I3C_BUS_MODE_MIXED_SLOW;
> > diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
> > index 44fb3cf..740235e 100644
> > --- a/include/linux/i3c/master.h
> > +++ b/include/linux/i3c/master.h
> > @@ -250,12 +250,17 @@ struct i3c_device {
> > * the bus. The only impact in this mode is that the
> > * high SCL pulse has to stay below 50ns to trick I2C
> > * devices when transmitting I3C frames
> > + * @I3C_BUS_MODE_MIXED_LIMITED: I2C devices without 50ns spike filter are
> > + * present on the bus. However they allows
> > + * compliance up to the maximum SDR SCL clock
> > + * frequency.
>
> However they support
> SCL clock running at maximum SDR rate
> (12.5MHz).
>
> > * @I3C_BUS_MODE_MIXED_SLOW: I2C devices without 50ns spike filter are present
> > * on the bus
> > */
> > enum i3c_bus_mode {
> > I3C_BUS_MODE_PURE,
> > I3C_BUS_MODE_MIXED_FAST,
> > + I3C_BUS_MODE_MIXED_LIMITED,
> > I3C_BUS_MODE_MIXED_SLOW,
> > };
> >
>
> The code itself looks good.
>
> Thanks,
>
> Boris

Thanks for your feedback I will address the fixes next version.


Best regards,
Vitor Soares


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