[PATCH 00/23] RFC: exynos multiplatform support
From: Thierry Reding <hidden>
Date: 2013-03-07 07:22:03
Also in:
linux-samsung-soc
On Thu, Mar 07, 2013 at 03:02:46AM +0000, Arnd Bergmann wrote:
On Wednesday 06 March 2013, Thierry Reding wrote:quoted
quoted
Option 2 would probably come down to having a trivial MFD driver exposing a regmap. You can probably reuse drivers/mfd/syscon.c for this and make the node compatible with "syscon" to designate the clock registers as a system-wide resource, making the other device nodes register-less.I think option 2 is the standard method if one hardware block provides several logical devices. I find it to be a pretty nice solution to this problem. We also have precedent in the PWM subsystem. The TWL chips for instance use it to create a platform device which is later driven by a PWM driver.One difference though is that the TWL chip is a heterogenous MFD that has a lot of different sub-devices, where in case of Exynos the timer device has a set of identical units, each of which can be used either as a PWM or as a clocksource or other timer.
I didn't know that. However I still making this an MFD driver is a good fit because it'll move the logic of defining the mode of each unit is kept in a parent driver which can instantiate the proper child devices for the corresponding subsystems. One big disadvantage of this approach is that if this is continued there is a risk that MFD will turn into a dump for all kinds of devices that provide more than a single service. So if people prefer option 3 I'm fine with it as well. Thierry -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 836 bytes Desc: not available URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20130307/44a92c5e/attachment.sig>