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From: Lee Jones <lee.jones@linaro.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: sameo@linux.intel.com, devicetree-discuss@lists.ozlabs.org,
	linux-kernel@vger.kernel.org, spear-devel@list.st.com,
	Vipul Kumar Samar <vipulkumar.samar@st.com>
Subject: Re: [PATCH V2 2/2] mfd: stmpe: Extend DT support in stmpe driver
Date: Fri, 23 Nov 2012 15:43:11 +0000	[thread overview]
Message-ID: <20121123154311.GA28552@gmail.com> (raw)
In-Reply-To: <CAKohpo=4orAgwVRRvukj+tu67CyVvoUegsJ7eXaCMA9exruqEA@mail.gmail.com>

On Fri, 23 Nov 2012, Viresh Kumar wrote:

> On 23 November 2012 15:06, Lee Jones <lee.jones@linaro.org> wrote:
> > On Fri, 23 Nov 2012, Viresh Kumar wrote:
> >>       pdev = platform_device_alloc(cell->name, id + cell->id);
> >>
> >> This is required when we have multiple instances of MFD device present
> >> on board. How do you want me to handle this ?
> >
> > There are lots of examples of this already. I have to leave something
> > to the imagination, or I'll be requesting a cut of your salary. :D
> 
> My manager already reduced my salary by 20% after reading this mail :(

Ah, Good. 

Tell your manager I'll send my offshore bank details over soon. :)

> Ok, this is what my understanding of whole this is. Platform devices are
> named like:
> - pdev-name: if id passed in pdev.id is -1
> - pdev-name.0[1|2|...]: if id passed is 0[1|2|...]
> - pdev-name.<dynamically allocated by kernel>: if id passed is -2
> 
> Now, we don't declare cell->id fields and they are currently zero and so
> value is passed from pdata->id field. So, for example with multiple instances
> of stmpe on a board, we have:
> 
> - stmpe-0: //Name just for reference...
>    - stmpe-gpio.0
>    - stmpe-ts.0
> - stmpe-1:
>    - stmpe-gpio.1
>    - stmpe-ts.1
> - stmpe-2:
>    - stmpe-gpio.2
>    - stmpe-ts.2
> 
> I main idea is to distinguish various instances of sub modules, like stmpe-gpio.
> And this works well with non-DT support we have currently.

Yes, when !DT, then passing ID is no problem.

> With DT, i am not sure how should we pass id field to mfd_add_devices(). If
> we pass it -1, then multiple instances will have same name: "stmpe-gpio"

No, in DT devices named as part of the hiearchy, so you'd have:

soc-u9500/i2c@80004000/stmpe1601@40/stmpe_keypad
soc-u9500/i2c@80004000/stmpe1601@41/stmpe_keypad
... etc

The only time we need to be concerned is if one stmpe device can
handle more than one keypad, gpio controller, etc. Which I don't
think is the case.

> Sorry, for my lack of knowledge. Don't send another mail with salary cut
> suggestion as that will make it -40% in total ;)

Ah, I promise I'll spend it wisely. :)

-- 
Lee Jones
Linaro ST-Ericsson Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

  reply	other threads:[~2012-11-23 15:43 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-22  5:10 [PATCH V2 1/2] mfd: stmpe: Use devm_*() routines Viresh Kumar
     [not found] ` <f1d508c64a01dfd492a1ab1fda28af4b7647d8ab.1353560936.git.viresh.kumar-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2012-11-22  5:10   ` [PATCH V2 2/2] mfd: stmpe: Extend DT support in stmpe driver Viresh Kumar
     [not found]     ` <b81641051dad9660b72b0028d001e5620d901160.1353560936.git.viresh.kumar-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2012-11-22 11:24       ` Lee Jones
     [not found]         ` <20121122112451.GE4328-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-11-22 13:54           ` Viresh Kumar
     [not found]             ` <CAKohpo=F91sZ7St3XVXqwAEgmSWXjAxxXwRs1RD5qPyW99P1vA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-11-22 15:46               ` Lee Jones
     [not found]                 ` <20121122154612.GC10986-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-11-22 17:01                   ` Viresh Kumar
2012-11-23  3:45                     ` Shiraz Hashim
     [not found]                       ` <20121123034557.GB5384-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2012-11-23  9:33                         ` Lee Jones
2012-11-23  9:23                     ` Lee Jones
2012-11-22 18:31           ` Viresh Kumar
2012-11-23  9:39             ` Lee Jones
2012-11-23  4:29           ` Viresh Kumar
2012-11-23  9:36             ` Lee Jones
2012-11-23 12:39               ` Viresh Kumar
2012-11-23 15:43                 ` Lee Jones [this message]
2012-11-23 15:45                   ` Viresh Kumar
2012-11-22 10:27   ` [PATCH V2 1/2] mfd: stmpe: Use devm_*() routines Lee Jones
     [not found]     ` <20121122102710.GD4328-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-11-22 10:30       ` Viresh Kumar
2012-11-22 17:10       ` Viresh Kumar
     [not found]         ` <CAKohpo=gctcd5+bZ8xeJn-Cx3=+=+uxaCzEoZhFmp+XaJSpf9Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-11-23  9:40           ` Lee Jones
2012-11-23  9:42             ` Lee Jones
2012-11-23  9:44             ` Viresh Kumar
2012-11-23 11:03 ` Samuel Ortiz

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