This adds devfreq support for imx8mm, covering dynamic scaling of internal NOC and DDR Controller Scaling for simple busses (NIC/NOC) is done through the clk framework while DRAM scaling is performed in firmware with an "imx-ddrc" wrapper for devfreq. Changes since RFCv3: * Implement passive support and set NOC parent to DDRC * Drop scaling AHB/AXI for now (NOC/DDRC use most power anyway) * Split into two devreq drivers (and bindings) because the ddrc is really a distinct piece of hardware. * Stop relying on clk_min_rate * Fetch info about dram clk parents from firmware instead of hardcoding in driver. This can more easily support additional rates. * Perform DRAM frequency inside devfreq instead of clk, mostly due to objections to earlier RFCs for "imx8m-dram-clk" * Link: https://patchwork.kernel.org/cover/11056779/ * Link: https://patchwork.kernel.org/patch/11049429/ Stephen: It would be very helpful if you could comment on the dram frequency switching code. I moved it outside of clk but now I have to use provider APIs outside of drivers/clk for parent manipulation. Few other drivers do that so maybe it's OK? Scaling buses can cause problems for devices with realtime bandwith requirements such as display, the intention is to use the interconnect framework to make DEV_PM_QOS_MIN_FREQUENCY to devfreq. There are separate patches for that: * https://patchwork.kernel.org/patch/11084279/ * https://patchwork.kernel.org/cover/11078671/ Leonard Crestez (7): clk: imx8m: Set CLK_GET_RATE_NOCACHE on dram_alt/apb dt-bindings: devfreq: Add bindings for generic imx buses PM / devfreq: Add generic imx bus driver dt-bindings: devfreq: Add bindings for imx ddr controller PM / devfreq: Add dynamic scaling for imx ddr controller PM / devfreq: imx-ddrc: Measure bandwidth with perf arm64: dts: imx8mm: Add devfreq nodes .../devicetree/bindings/devfreq/imx-ddrc.yaml | 53 ++ .../devicetree/bindings/devfreq/imx.yaml | 50 ++ arch/arm64/boot/dts/freescale/imx8mm.dtsi | 51 +- drivers/clk/imx/clk-imx8mm.c | 6 +- drivers/clk/imx/clk-imx8mn.c | 6 +- drivers/clk/imx/clk-imx8mq.c | 7 +- drivers/devfreq/Kconfig | 12 + drivers/devfreq/Makefile | 1 + drivers/devfreq/imx-ddrc.c | 511 ++++++++++++++++++ drivers/devfreq/imx-devfreq.c | 148 +++++ 10 files changed, 837 insertions(+), 8 deletions(-) create mode 100644 Documentation/devicetree/bindings/devfreq/imx-ddrc.yaml create mode 100644 Documentation/devicetree/bindings/devfreq/imx.yaml create mode 100644 drivers/devfreq/imx-ddrc.c create mode 100644 drivers/devfreq/imx-devfreq.c -- 2.17.1
