Messages in this thread | | | Date | Tue, 16 Apr 2019 08:00:49 +0200 | From | Boris Brezillon <> | Subject | Re: [PATCH 2/3] i3c: add mixed limited bus mode |
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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
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