On 29 July 2016 at 15:15, Mark Rutland <mark.rutland@xxxxxxx> wrote: > On Fri, Jul 29, 2016 at 02:58:32PM +0200, Rafał Miłecki wrote: >> From: Rafał Miłecki <rafal@xxxxxxxxxx> >> >> This clock is present on cheaper Northstar devices like BCM53573 or >> BCM47189 using Corex-A7. This driver uses PMU (Power Management Unit) >> to calculate clock rate and allows using it in a generic (clk_*) way. >> >> Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx> >> --- >> .../devicetree/bindings/clock/brcm,ns-ilp.txt | 28 ++++ >> drivers/clk/bcm/Makefile | 1 + >> drivers/clk/bcm/clk-ns-ilp.c | 146 +++++++++++++++++++++ >> 3 files changed, 175 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt >> create mode 100644 drivers/clk/bcm/clk-ns-ilp.c >> >> diff --git a/Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt b/Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt >> new file mode 100644 >> index 0000000..c4df38e >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt >> @@ -0,0 +1,28 @@ >> +Broadcom Northstar ILP clock >> +============================ >> + >> +This binding uses the common clock binding: >> + Documentation/devicetree/bindings/clock/clock-bindings.txt >> + >> +This binding is used for ILP clock on Broadcom Northstar devices using >> +Corex-A7 CPU. ILP clock depends on ALP one and has to be calculated on >> +runtime. >> + >> +Required properties: >> +- compatible: "brcm,ns-ilp" >> +- reg: iomem address range of PMU (Power Management Unit) >> +- reg-names: "pmu", the only needed & supported reg right now > > From the commit message and binding description, it sounds like there > should be a binding for the PMU, and that should cover the clocks > required/exported by the PMU. This is a bit of problem, because PMU handles a lot of different stuff and is used by various drivers. Some examples of what you can do with/find on a PMU: 1) Power management 2) Watchdog 3) Timer 4) XTAL 5) PLLs 6) Control registers for some ARM debugging (whatever it is), UART, JTAG, more PMU is used by different drivers, e.g.: 1) Ethernet driver 2) Wireless driver 3) NAND controller driver I don't have access to Broadcom's datasheets so unfortunately I can't provide all details. >> +- clocks: should reference an ALP clock >> +- clock-names: "alp", the only needed & supported clock right now >> +- #clock-cells: should be <0> > > How many clocks does the PMU output, including the ILP clock? Well, ALP clock (AKA XTAL clock) is definitely part of PMU. It's a fixed rate clock with rate specific to the chip. I think ILP is also part of PMU (again: I don't have datasheets) as PMU has this ALP_PER_4ILP register. >From Broadcom's SDK I can say they also have "ARM debug unit" on some chipsets. It requires enabling "ARM debug clk" to operate which is handled by PMU as well. -- Rafał -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
