[PATCH V4 1/2] i3c: master: support to adjust first broadcast address speed

[Frank Li]

On Mon, Sep 09, 2024 at 11:03:29PM +0200, Alexandre Belloni wrote:
> On 09/09/2024 15:58:40-0400, Frank Li wrote:
> > On Thu, Sep 05, 2024 at 03:45:56PM +0800, Carlos Song wrote:
> > > According to I3C spec 6.2 Timing Specification, the Open Drain High Period
> > > of SCL Clock timing for first broadcast address should be adjusted to 200ns
> > > at least. I3C device working as i2c device will see the broadcast to close
> > > its Spike Filter then change to work at I3C mode. After that I3C open drain
> > > SCL high level should be adjusted back.
> > >
> > > Signed-off-by: Carlos Song <carlos.song at nxp.com>
> > > Reviewed-by: Miquel Raynal <miquel.raynal at bootlin.com>
> > > Reviewed-by: Frank Li <Frank.Li at nxp.com>
> >
> > Alexandre Belloni:
> >
> > 	I have not seen these in patch work
> > 	https://patchwork.kernel.org/project/linux-i3c/list/
> >
> > 	Any thing wrong. These two patches is critial for some boards.
> > Could you please take care it?
>
> They didn't make it to the list, please subscribe and resend. Also, it
> is very very difficult to keep track of all the patches you sent s I'm
> not sure what actually needs to be applied and what has been dropped r
> superseded.

Sorry for that. Only one big patches set (about hotjoin fix) and update
maintaner are directly sent from me.

There are 3 patches from carlos.
one patch already in patchwork
https://patchwork.kernel.org/project/linux-i3c/patch/20240719080233.842771-1-carlos.song@nxp.com/
the other two patches is what's talking about in this email.

Anther one from Ravindra can be dropped.

I am not sure how I can help this because there are difference contributor.

Frank

>
> >
> > best regards
> > Frank Li
> >
> > > ---
> > > Change for V4:
> > > - No change. Send this patch with svc-i3c-master.c fix patch.
> > > Change for V3:
> > > - Modify comments from Miquel's suggestion
> > > Chnage for V2:
> > > - Fix set_speed description from Frank's comment
> > > ---
> > >  drivers/i3c/master.c       | 12 ++++++++++++
> > >  include/linux/i3c/master.h | 16 ++++++++++++++++
> > >  2 files changed, 28 insertions(+)
> > >
> > > diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> > > index 7028f03c2c42..6f3eb710a75d 100644
> > > --- a/drivers/i3c/master.c
> > > +++ b/drivers/i3c/master.c
> > > @@ -1868,6 +1868,12 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
> > >  		goto err_bus_cleanup;
> > >  	}
> > >
> > > +	if (master->ops->set_speed) {
> > > +		ret = master->ops->set_speed(master, I3C_OPEN_DRAIN_SLOW_SPEED);
> > > +		if (ret)
> > > +			goto err_bus_cleanup;
> > > +	}
> > > +
> > >  	/*
> > >  	 * Reset all dynamic address that may have been assigned before
> > >  	 * (assigned by the bootloader for example).
> > > @@ -1876,6 +1882,12 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
> > >  	if (ret && ret != I3C_ERROR_M2)
> > >  		goto err_bus_cleanup;
> > >
> > > +	if (master->ops->set_speed) {
> > > +		master->ops->set_speed(master, I3C_OPEN_DRAIN_NORMAL_SPEED);
> > > +		if (ret)
> > > +			goto err_bus_cleanup;
> > > +	}
> > > +
> > >  	/* Disable all slave events before starting DAA. */
> > >  	ret = i3c_master_disec_locked(master, I3C_BROADCAST_ADDR,
> > >  				      I3C_CCC_EVENT_SIR | I3C_CCC_EVENT_MR |
> > > diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
> > > index 074f632868d9..2a1ed05d5782 100644
> > > --- a/include/linux/i3c/master.h
> > > +++ b/include/linux/i3c/master.h
> > > @@ -277,6 +277,20 @@ enum i3c_bus_mode {
> > >  	I3C_BUS_MODE_MIXED_SLOW,
> > >  };
> > >
> > > +/**
> > > + * enum i3c_open_drain_speed - I3C open-drain speed
> > > + * @I3C_OPEN_DRAIN_SLOW_SPEED: Slow open-drain speed for sending the first
> > > + *				broadcast address. The first broadcast address at this speed
> > > + *				will be visible to all devices on the I3C bus. I3C devices
> > > + *				working in I2C mode will turn off their spike filter when
> > > + *				switching into I3C mode.
> > > + * @I3C_OPEN_DRAIN_NORMAL_SPEED: Normal open-drain speed in I3C bus mode.
> > > + */
> > > +enum i3c_open_drain_speed {
> > > +	I3C_OPEN_DRAIN_SLOW_SPEED,
> > > +	I3C_OPEN_DRAIN_NORMAL_SPEED,
> > > +};
> > > +
> > >  /**
> > >   * enum i3c_addr_slot_status - I3C address slot status
> > >   * @I3C_ADDR_SLOT_FREE: address is free
> > > @@ -436,6 +450,7 @@ struct i3c_bus {
> > >   *		      NULL.
> > >   * @enable_hotjoin: enable hot join event detect.
> > >   * @disable_hotjoin: disable hot join event detect.
> > > + * @set_speed: adjust I3C open drain mode timing.
> > >   */
> > >  struct i3c_master_controller_ops {
> > >  	int (*bus_init)(struct i3c_master_controller *master);
> > > @@ -464,6 +479,7 @@ struct i3c_master_controller_ops {
> > >  				 struct i3c_ibi_slot *slot);
> > >  	int (*enable_hotjoin)(struct i3c_master_controller *master);
> > >  	int (*disable_hotjoin)(struct i3c_master_controller *master);
> > > +	int (*set_speed)(struct i3c_master_controller *master, enum i3c_open_drain_speed speed);
> > >  };
> > >
> > >  /**
> > > --
> > > 2.34.1
> > >
>
> --
> Alexandre Belloni, co-owner and COO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com