linux-kernel - Re: [PATCH v8 4/4] Input: synaptics-rmi4

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Message-ID: <20160624233505.GC11719@dtor-ws>
Date:	Fri, 24 Jun 2016 16:35:05 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
Cc:	Wolfram Sang <wsa@...-dreams.de>, Jonathan Corbet <corbet@....net>,
	Corey Minyard <minyard@....org>,
	Jean Delvare <jdelvare@...e.de>,
	Guenter Roeck <linux@...ck-us.net>,
	Andrew Duggan <aduggan@...aptics.com>,
	Christopher Heiny <cheiny@...aptics.com>,
	linux-i2c@...r.kernel.org, linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-input@...r.kernel.org
Subject: Re: [PATCH v8 4/4] Input: synaptics-rmi4 - add SMBus support

On Fri, Jun 24, 2016 at 09:19:32AM +0200, Benjamin Tissoires wrote:
> On Jun 23 2016 or thereabouts, Dmitry Torokhov wrote:
> > On Thu, Jun 09, 2016 at 04:53:50PM +0200, Benjamin Tissoires wrote:
> > > +
> > > +static struct i2c_driver rmi_smb_driver = {
> > > +	.driver = {
> > > +		.owner	= THIS_MODULE,
> > > +		.name	= "rmi4_smbus",
> > > +		.pm	= &rmi_smb_pm,
> > > +		.resume	= rmi_smb_resume,
> > 
> > Why rmi_smb_resume is not part of rmi_smb_pm?
> > 
> 
> This is because rmi_smbus device both have a PS/2 interface and a SMBus
> one. I'll have to check again now that I have a slightly different way
> of binding smbus devices in my tree, but the issue was:
> - having resume part of pm means it will get caught by PM directly
> - the PS/2 node gets also resumed by PM
> - calling PS/2 commands during resume switches the devices back into
>   PS/2 and stops the SMBus communication.
> 
> So it's easier to wait only for the PS/2 PM resume call which will call
> the SMBus resume function when the device is in a proper state.
> 
> I'll send out the updated patch with your comments next week hopefully.

Hmm, I think you will have to walk me through resume process. How do we
tie in PS/2 and I2C on these devices abd have PS/2 code call into this
driver?

Thanks.

-- 
Dmitry