| Message ID | 1450474676-10210-3-git-send-email-jonmason@broadcom.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Friday 18 December 2015 16:37:56 Jon Mason wrote: > + cru: cru@1800c184 { > + compatible = "syscon"; > + reg = <0x1800c184 0xc>; > + }; It's unusual for a device to start at such an odd address. Are you sure it's not a larger device starting at 0x1800c000 or 0x18000000? Also, please provide a more specific compatible string based on the name of the device in the data sheet. The node name in contrast should be more generic, e.g. cru: system-controller@1800c000 { compatible = "brcm,bcm53010-cru", "syscon"; reg = <0x1800c000 0x400>; /* whatever the data sheet says */ }; Arnd
On Fri, Dec 18, 2015 at 10:44:28PM +0100, Arnd Bergmann wrote: > On Friday 18 December 2015 16:37:56 Jon Mason wrote: > > + cru: cru@1800c184 { > > + compatible = "syscon"; > > + reg = <0x1800c184 0xc>; > > + }; > > It's unusual for a device to start at such an odd address. Are you sure > it's not a larger device starting at 0x1800c000 or 0x18000000? The CRU (Clock and Reset Unit) starts at 0x1800c100, with the following layout: CRU Clock Management at 0x1800c100-0x1800c180 CRU Reset at 0x1800c184 CRU Period Sample Clock at 0x1800c188 CRU Interrupt register at 0x1800c18c CRU MDIO Control at 0x1800c190 CRU GPIO at 0x1800c1c0-0x1800c1e0 CRU SDIO 0x1800c200-0x1800c214 CRU RoboSW Interrupt at 0x1800c280 CRU Straps Control at 0x1800c2a0 The clock driver is already referencing the registers between 0x1800c100-0x1800c180, and the GPIO driver is referencing registers between 0x1800c1c0-0x1800c1e0. The reset part of the syscon seems to be the only useful thing in this block. Am I approaching this incorrectly? > Also, please provide a more specific compatible string based on the > name of the device in the data sheet. The node name in contrast should > be more generic, e.g. > > cru: system-controller@1800c000 { > compatible = "brcm,bcm53010-cru", "syscon"; This is very similar between the NS and NSP (and NS2) platforms. I'll verify the layout and see if this can't be "brcm,iproc-cru" or something similar. Thanks, Jon > reg = <0x1800c000 0x400>; /* whatever the data sheet says */ > }; > > > Arnd >
On Tuesday 05 January 2016 17:26:06 Jon Mason wrote: > On Fri, Dec 18, 2015 at 10:44:28PM +0100, Arnd Bergmann wrote: > > On Friday 18 December 2015 16:37:56 Jon Mason wrote: > > > + cru: cru@1800c184 { > > > + compatible = "syscon"; > > > + reg = <0x1800c184 0xc>; > > > + }; > > > > It's unusual for a device to start at such an odd address. Are you sure > > it's not a larger device starting at 0x1800c000 or 0x18000000? > > The CRU (Clock and Reset Unit) starts at 0x1800c100, with the > following layout: > > CRU Clock Management at 0x1800c100-0x1800c180 > CRU Reset at 0x1800c184 > CRU Period Sample Clock at 0x1800c188 > CRU Interrupt register at 0x1800c18c > CRU MDIO Control at 0x1800c190 > CRU GPIO at 0x1800c1c0-0x1800c1e0 > CRU SDIO 0x1800c200-0x1800c214 > CRU RoboSW Interrupt at 0x1800c280 > CRU Straps Control at 0x1800c2a0 > > The clock driver is already referencing the registers between > 0x1800c100-0x1800c180, and the GPIO driver is referencing registers > between 0x1800c1c0-0x1800c1e0. > > The reset part of the syscon seems to be the only useful thing in this > block. Am I approaching this incorrectly? I think the problem is how the gpio controller has a device node that overlaps with one of the devices of the chip. If the data sheet lists a "Clock and Reset Unit" at those addresses, that is a strong indication that this is actually a specific piece of hardware, and it should be represented as one device node in DT, with the sub-registers being exposed by that driver in some way. A typical way would be to have a syscon node like cru: syscon@1800c100 { compatible = "brcm,bcm53010-clock-reset-unit", "syscon"; reg = <0x1800c100 100>; }; that represents the entire unit. You can then have syscon references in each driver that uses it, and/or create a high-level driver that binds to the "brcm,bcm53010-clock-reset-unit" compatible string and that exports a set of functions for other drivers to be used if you prefer to do this as functional abstraction rather than register based. > > Also, please provide a more specific compatible string based on the > > name of the device in the data sheet. The node name in contrast should > > be more generic, e.g. > > > > cru: system-controller@1800c000 { > > compatible = "brcm,bcm53010-cru", "syscon"; > > This is very similar between the NS and NSP (and NS2) platforms. I'll > verify the layout and see if this can't be "brcm,iproc-cru" or > something similar. If it's only "very similar" but not identical, don't use the same compatible string, at least not as the only one. You should be able to identify the specific device by looking at its compatible string in case you want to write a high-level driver that knows about the differences later (the driver should not need to inquire the chip name, it should only look at one device node). Arnd
diff --git a/arch/arm/boot/dts/bcm5301x.dtsi b/arch/arm/boot/dts/bcm5301x.dtsi index 553b2ec..2a482ec 100644 --- a/arch/arm/boot/dts/bcm5301x.dtsi +++ b/arch/arm/boot/dts/bcm5301x.dtsi @@ -246,6 +246,18 @@ "sata2"; }; + cru: cru@1800c184 { + compatible = "syscon"; + reg = <0x1800c184 0xc>; + }; + + reboot@1800c184 { + compatible ="syscon-reboot"; + regmap = <&cru>; + offset = <0>; + mask = <0x39>; + }; + nand: nand@18028000 { compatible = "brcm,nand-iproc", "brcm,brcmnand-v6.1", "brcm,brcmnand"; reg = <0x18028000 0x600>, <0x1811a408 0x600>, <0x18028f00 0x20>;
Add the ability to reboot via a reset of the processor. This is achieved via a write of 0x39 to the CRU Reset Register. Unfortunately, this only resets the core and not the other IP blocks. So if possible, other methods should be used on the individual boards. Signed-off-by: Jon Mason <jonmason@broadcom.com> --- arch/arm/boot/dts/bcm5301x.dtsi | 12 ++++++++++++ 1 file changed, 12 insertions(+)