linux-kernel - Re: [PATCH v6 01/10] i3c: Add core I3C infrastructure

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Message-ID: <20180824143934.6d6b6487@bbrezillon>
Date:   Fri, 24 Aug 2018 14:39:34 +0200
From:   Boris Brezillon <boris.brezillon@...tlin.com>
To:     vitor <Vitor.Soares@...opsys.com>, <linux-gpio@...r.kernel.org>,
        Sekhar Nori <nsekhar@...com>
Cc:     Wolfram Sang <wsa@...-dreams.de>, <linux-i2c@...r.kernel.org>,
        Jonathan Corbet <corbet@....net>, <linux-doc@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        Przemyslaw Sroka <psroka@...ence.com>,
        Arkadiusz Golec <agolec@...ence.com>,
        Alan Douglas <adouglas@...ence.com>,
        Bartosz Folta <bfolta@...ence.com>,
        Damian Kos <dkos@...ence.com>,
        Alicja Jurasik-Urbaniak <alicja@...ence.com>,
        Cyprian Wronka <cwronka@...ence.com>,
        Suresh Punnoose <sureshp@...ence.com>,
        Rafal Ciepiela <rafalc@...ence.com>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Nishanth Menon <nm@...com>, Rob Herring <robh+dt@...nel.org>,
        Pawel Moll <pawel.moll@....com>,
        Mark Rutland <mark.rutland@....com>,
        Ian Campbell <ijc+devicetree@...lion.org.uk>,
        "Kumar Gala" <galak@...eaurora.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Xiang Lin <Xiang.Lin@...aptics.com>,
        Przemyslaw Gaj <pgaj@...ence.com>,
        Peter Rosin <peda@...ntia.se>
Subject: Re: [PATCH v6 01/10] i3c: Add core I3C infrastructure

Hi Vitor,

On Wed, 22 Aug 2018 17:43:34 +0100
vitor <Vitor.Soares@...opsys.com> wrote:

> Hi Boris,
> 
> 
> On 19-07-2018 16:29, Boris Brezillon wrote:
> > +int i3c_bus_register(struct i3c_bus *i3cbus)
> > +{
> > +	struct i2c_dev_desc *desc;
> > +
> > +	i3c_bus_for_each_i2cdev(i3cbus, desc) {
> > +		switch (desc->boardinfo->lvr & I3C_LVR_I2C_INDEX_MASK) {
> > +		case I3C_LVR_I2C_INDEX(0):
> > +			if (i3cbus->mode < I3C_BUS_MODE_MIXED_FAST)
> > +				i3cbus->mode = I3C_BUS_MODE_MIXED_FAST;
> > +			break;
> > +
> > +		case I3C_LVR_I2C_INDEX(1):
> > +		case I3C_LVR_I2C_INDEX(2):
> > +			if (i3cbus->mode < I3C_BUS_MODE_MIXED_SLOW)
> > +				i3cbus->mode = I3C_BUS_MODE_MIXED_SLOW;
> > +			break;
> > +
> > +		default:
> > +			return -EINVAL;
> > +		}
> > +	}
> > +
> > +	if (!i3cbus->scl_rate.i3c)
> > +		i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
> > +
> > +	if (!i3cbus->scl_rate.i2c) {
> > +		if (i3cbus->mode == I3C_BUS_MODE_MIXED_SLOW)
> > +			i3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_SCL_RATE;
> > +		else
> > +			i3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_PLUS_SCL_RATE;
> > +	}
> > +
> > +	/*
> > +	 * I3C/I2C frequency may have been overridden, check that user-provided
> > +	 * values are not exceeding max possible frequency.
> > +	 */
> > +	if (i3cbus->scl_rate.i3c > I3C_BUS_MAX_I3C_SCL_RATE ||
> > +	    i3cbus->scl_rate.i2c > I3C_BUS_I2C_FM_PLUS_SCL_RATE) {
> > +		return -EINVAL;
> > +	}
> > +
> > +	dev_set_name(&i3cbus->dev, "i3c-%d", i3cbus->id);
> > +
> > +	return device_add(&i3cbus->dev);
> > +}  
> During the tests of the bus with i2c devices I found the i2c_dev_desc 
> objects aren't allocated before this function. This cause i3cbus->mode = 
> I3C_BUS_MODE_PURE.

I just checked and DT parsing (+ I2C descs creation) is done before
i3c_bus_register() is called, so we should be good. How did you declare
your I2C devices (right now, only DT declaration is supported).

> 
> I want to do something for the slave and secondary master, do you 
> already have infrastructure that you can share?

What do you mean?

Regards,

Boris