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From: Vitor Soares <vitor.soares@synopsys.com>
To: Boris Brezillon <boris.brezillon@collabora.com>,
	Vitor Soares <vitor.soares@synopsys.com>
Cc: "linux-i3c@lists.infradead.org" <linux-i3c@lists.infradead.org>,
	"joao.pinto@synopsys.com" <joao.pinto@synopsys.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Boris Brezillon <bbrezillon@kernel.org>
Subject: RE: [PATCH 2/3] i3c: add mixed limited bus mode
Date: Tue, 16 Apr 2019 14:27:10 +0000
Message-ID: <13D59CF9CEBAF94592A12E8AE55501350A615980@DE02WEMBXB.internal.synopsys.com> (raw)
In-Reply-To: <20190416080049.5a6053b0@collabora.com>

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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Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-15 18:46 [PATCH 0/3] Fix i2c and i3c scl rate according " Vitor Soares
2019-04-15 18:46 ` [PATCH 1/3] i3c: fix i2c and i3c scl rate by " Vitor Soares
2019-04-16  5:50   ` Boris Brezillon
2019-04-16 14:24     ` Vitor Soares
2019-04-16 14:52       ` Boris Brezillon
2019-04-22 15:54         ` Vitor Soares
2019-04-22 16:07           ` Boris Brezillon
2019-04-22 17:54             ` Vitor Soares
2019-04-22 18:27               ` Boris Brezillon
2019-04-22 19:59                 ` Vitor Soares
2019-04-15 18:46 ` [PATCH 2/3] i3c: add mixed limited " Vitor Soares
2019-04-16  6:00   ` Boris Brezillon
2019-04-16 14:27     ` Vitor Soares [this message]
2019-04-15 18:46 ` [PATCH 3/3] i3c: dw: Add limited bus mode support Vitor Soares
2019-04-16  6:09   ` Boris Brezillon

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