On Monday, October 13, 2014 05:02:13 PM Aaron Lu wrote: > On Thu, Oct 09, 2014 at 05:21:28PM +0800, Aaron Lu wrote: > > On 10/08/2014 04:05 PM, Lee Jones wrote: > > > To all those CC'ed, > > > > > >> The Baytrail-T platform firmware has defined two customized operation > > >> regions for PMIC chip Crystal Cove - one is for power resource handling > > >> and one is for thermal: sensor temperature reporting, trip point setting, > > >> etc. This patch adds support for them on top of the existing Crystal Cove > > >> PMIC driver. > > >> > > >> The reason to split code into a separate file intel_soc_pmic_opregion.c > > >> is that there are more PMIC driver with ACPI operation region support > > >> coming and we can re-use those code. The intel_soc_pmic_opregion_data > > >> structure is created also for this purpose: when we need to support a > > >> new PMIC's operation region, we just need to fill those callbacks and > > >> the two register mapping tables. > > >> > > >> Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx> > > >> --- > > >> drivers/mfd/Kconfig | 11 + > > >> drivers/mfd/Makefile | 1 + > > >> drivers/mfd/intel_soc_pmic_crc.c | 3 + > > >> drivers/mfd/intel_soc_pmic_crc_opregion.c | 229 +++++++++++++++++++ > > >> drivers/mfd/intel_soc_pmic_opregion.c | 350 ++++++++++++++++++++++++++++++ > > >> drivers/mfd/intel_soc_pmic_opregion.h | 35 +++ > > > > > > With the influx of new same-chip devices, I think the MFD subsystem is > > > fast becoming overloaded. I think all of the PMIC handling should in > > > fact either live in Regulators or have its own subsystem. > > > > > > Let's open this up to the floor by Cc'ing some probable interested > > > parties. > > > > The ACPI operation region handler provides implementation for the ASL > > code written by firmware developer, and since the ACPI PMIC device node > > has two customized operation regions: power rail handling and thermal > > sensor manipulating, implementing the handler will inevitably touch > > power rail registers and thermal registers of the PMIC chip. In this > > regard, it doesn't fit what the MFD subsystem is meant to contain( > > according to your comments, I didn't know this before, sorry about that). > > > > It seems that we have two options: > > 1 Create two cell devices from the PMIC I2C driver, one for power and > > one for thermal; the driver for the power part goes to drivers/power > > or drivers/regulator and the driver for thermal one goes to > > drivers/thermal; > > The problem of this approach is that, the operation region handler > > driver doesn't really need to expose those power or thermal sysfs > > interfaces for user space to consume, perhaps it shouldn't, as its > > sole purpose is to satisfy the ASL code access, not more. > > 2 Move these operation region handler drivers to drivers/acpi > > We now have EC operation region handler driver there, but we also have > > I2C, GPIO, i915 operation region handlers in their own subsystems. Not > > sure if PMIC operation region handler qualifies there. > > Rafael, > > May I have your opinion on option 2? Do you think it is OK to place the > operation region code under drivers/acpi? Thanks. In my opinion, yes it is. After all, operation regions are a mechanism by which the AML interpreter can access hardware. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
