Messages in this thread | | | Date | Wed, 15 Jul 2015 17:59:12 +0300 | From | Tero Kristo <> | Subject | Re: [PATCH v2 3/3] ARM: dts: dra7: Add syscon-pllreset syscon to SATA PHY |
| |
On 07/15/2015 04:47 PM, Roger Quadros wrote: > Hi, > > On 15/07/15 15:07, Tony Lindgren wrote: >> * Kishon Vijay Abraham I <kishon@ti.com> [150715 04:24]: >>> Hi Roger, >>> >>> On Tuesday 02 June 2015 02:40 PM, Roger Quadros wrote: >>>> This register is required to be passed to the SATA PHY driver >>>> to workaround errata i783 (SATA Lockup After SATA DPLL Unlock/Relock). >>>> >>>> Signed-off-by: Roger Quadros <rogerq@ti.com> >>>> Signed-off-by: Sekhar Nori <nsekhar@ti.com> >>>> --- >>>> arch/arm/boot/dts/dra7.dtsi | 1 + >>>> 1 file changed, 1 insertion(+) >>>> >>>> diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi >>>> index f03a091..260f300 100644 >>>> --- a/arch/arm/boot/dts/dra7.dtsi >>>> +++ b/arch/arm/boot/dts/dra7.dtsi >>>> @@ -1135,6 +1135,7 @@ >>>> ctrl-module = <&omap_control_sata>; >>>> clocks = <&sys_clkin1>, <&sata_ref_clk>; >>>> clock-names = "sysclk", "refclk"; >>>> + syscon-pllreset = <&dra7_ctrl_core 0x3fc>; >>> >>> I think all users of syscon should be made child node of scm_conf. Tony and >>> Tero, is that right? > > It can't be child of scm_conf as the address is outside it's range. > Looks like I have to add a new child to scm node that maps beyond > the dra7_pmx_core padconf address range. > >>> >>> If so, then we might have to modify the driver too. >> >> Yeah there should not be much need to use syscon outside scm_conf >> area and for I2C devices. If there's some other misc register area >> in dra7 in addition to scm_conf then it might make sense to use it. >> >> But in general, for the SCM registers, just a normal loadable kernel >> driver module doing of_ioremap on a dedicated range of registers is >> always a better option :) >> > > Lets take for example this register CTRL_CORE_SMA_SW_0. > It has the SATA PLL_SOFT_RESET bit, EMIF1/2 gating control bits > and ISOLATE bit. > > I don't see this fitting in any driver except the syscon approach. > > cheers, > -roger >
Yea I think scm_conf can generally contain lots of weird registers that can have multiple users / use-cases. This is the junk-yard of SoC features the designers had no idea where to put them; so they put it under scm_conf.
I'd say in some cases we are probably forced to map to it from other drivers, this is one of the reasons it is a syscon map in the first place, and generally speaking, they should not be children of scm_conf in the DT layout.
You could probably add a "dummy" node under scm_conf which maps to the scm register, and which you would refer to from the sata driver.
-Tero
| |