Messages in this thread | | | Date | Fri, 4 Feb 2011 02:16:41 -0800 | From | Andres Salomon <> | Subject | Re: [PATCH 15/19] mc13xxx: mfd_cell is now implicitly available to drivers |
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On Fri, 4 Feb 2011 10:34:58 +0100 Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:
> Hello Andres, > > On Wed, Feb 02, 2011 at 08:20:15PM -0800, Andres Salomon wrote: > > > > No need to explicitly set the cell's platform_data/data_size. > > > > In this case, move the various platform_data pointers > > to driver_data. All of the clients which make use of it > > are also changed. > > > > Mfd-core makes a copy of platform_data, but driver_data keeps a > > pointer to the original data. Because each cell's platform_data > > previously pointed to a local (stack) variable, the various ARM > > mach types that set the pdata are updated to keep the memory around. > I didn't get this even after reading it 5 times. You wrote in the > subject that drivers now have access to mfd_cell. I don't see where > e.g. drivers/leds/leds-mc13783.c uses that?! Does this depend on some > mfd-changes I don't see and this is just a first step? > > After reading the changes I think I understood: > > - You made things that were passed as platform_data before available > via driver_data.
Right. And as someone pointed out, this doesn't really work as well as I'd hoped, so I'll have to refine my approach. Ideally, something simpler..
> - Because platform_data is copied and driver_data is not at register > time, the data being platform_data cannot be __initdata or stack > local anymore, so this needs fixing. > > In sum this results in .data becoming bigger (which is bad). > > And I think this patch has a conceptual problem, too. In my opionion > platform_data is the point to hand over platform specific data to a > driver. driver_data is something that is private to the driver and > has to be considered opaque for the platform. The driver was sort of > OK before ...
I'll be sending updated patches once I've reworked things. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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