linux-kernel - Re: [PATCH 07/12] mfd: syscon: Consider platform data a regmap config name

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140212111804.GZ15081@lee--X1>
Date:	Wed, 12 Feb 2014 11:18:04 +0000
From:	Lee Jones <lee.jones@...aro.org>
To:	Pawel Moll <pawel.moll@....com>
Cc:	Alexander Shiyan <shc_work@...l.ru>,
	"arm@...nel.org" <arm@...nel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Samuel Ortiz <sameo@...ux.intel.com>
Subject: Re: [PATCH 07/12] mfd: syscon: Consider platform data a regmap
 config name

> > > > Use the device platform data as a regmap config
> > > > name. This is particularly useful in the regmap
> > > > debugfs when there is more than one syscon device
> > > > registered, to distinguish the register blocks.
> > > > 
> > > > Cc: Samuel Ortiz <sameo@...ux.intel.com>
> > > > Cc: Lee Jones <lee.jones@...aro.org>
> > > > Signed-off-by: Pawel Moll <pawel.moll@....com>
> > > > ---
> > > ...
> > > > syscon_regmap_config.max_register = res->end - res->start - 3;
> > > > +	syscon_regmap_config.name = dev_get_platdata(&pdev->dev);
> > > 
> > > Is dev_name(&pdev->dev) can be used for such purpose?
> > 
> > Yes of course.
> > 
> > Either use the automatically generated name or over-ride with
> > dev->init_name prior to registration or call dev_set_name()
> > manually. Then retrieve with Alexander's suggestion.
> > 
> > Is there any technical reason why this is not possible with your
> > implementation?
> 
> Hold on, guys. Let me just point out that we're talking "non-DT"
> platform devices here (either statically defined struct
> platform_device-s or - my case - the MFD cells).
> 
> In this case device/driver matching relies completely on device name.
> Either the pdev->name must be identical (strcmp) to pdrv->name, or the
> pdev->name must be identical (strcmp again) to one of the pdev->id_table
> entries. See platform_match() in driver/base/platform.c for more
> details.
> 
> Therefore the dev_name(&pdev->dev) on a non-DT-originating sysconf
> devince will always return "sysconf.*", unless you're ready to maintain
> a growing syscon_ids[] list. If so, I will have to add three entries
> there ("sys_id", "sys_misc" and "sys_procid"). I hope you are not
> seriously considering this idea :-) After all that's what the
> platform_data was invented for.

Ah, I see your predicament. I guess that is a limitation of the was
syscon works. Usually we'd use match tables to differentiate between
various supported devices, but I guess the 'supported devices' list
for syscon is pretty limitless. In which case I support your second
implementation (adding a platform_data container) for the use of
arbitrary/useful-common names.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/