Hi Chris, On Fri, Dec 6, 2019 at 2:43 PM Chris Brandt <chris.brandt@xxxxxxxxxxx> wrote: > Document the bindings used by the Renesas SPI bus space controller. > > Signed-off-by: Chris Brandt <chris.brandt@xxxxxxxxxxx> > --- > v2: > * change to YAML format > * add interrupts property > * Used more terms directly from the hardware manual Thanks for the update! > --- /dev/null > +++ b/Documentation/devicetree/bindings/spi/renesas,spibsc.yaml > @@ -0,0 +1,115 @@ > +# SPDX-License-Identifier: GPL-2.0 > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/spi/renesas,spibsc.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: Renesas SPI Bus Space Controller (SPIBSC) Device Tree Bindings > + > +description: | > + Otherwise referred to as the "SPI Multi I/O Bus Controller" in SoC hardware > + manuals. This controller was designed specifically for accessing Serial flash > + devices such as SPI Flash, HyperFlash and OctaFlash. The HW can operate in two > + modes. One mode allows for normal byte by byte access (refereed to as > + "Manual Mode"). The other mode allows for direct memory mapped access (read > + only) to the flash area by the CPU (refereed to as "External Address Space > + Read Mode"). > + > +allOf: > + - $ref: spi-controller.yaml# > + > +maintainers: > + - Chris Brandt <chris.brandt@xxxxxxxxxxx> > + > +properties: > + compatible: > + oneOf: > + - items: > + - enum: > + - renesas,r7s72100-spibsc # RZ/A1 > + - renesas,r7s9210-spibsc # RZ/A2 > + > + reg: > + minItems: 2 > + maxItems: 2 > + items: > + - description: Registers > + - description: Memory Mapped Address Space The second one is not needed, if you would add "ranges" for the memory-mapped mode. > + > + interrupts: > + description: Some HW versions do not contain interrupts > + maxItems: 1 > + > + clocks: > + maxItems: 1 > + > + flash: > + description: | > + (Optional) In order to use the HW for R/W access ("Manual Mode"), a "flash" > + subnode must be present with a "compatible" property that contains > + "jedec,spi-nor". If a spi-nor property is not found, the HW is assumed to be > + already operating in "External Address Space Read Mode". > + > +required: > + - compatible > + - reg > + - clocks > + - '#address-cells' > + - '#size-cells' I would make the flash subnode mandatory. > + > +examples: > + - | > + # This example is for "Manual Mode" > + spibsc: spi@1f800000 { > + compatible = "renesas,r7s9210-spibsc"; > + reg = <0x1f800000 0x100>, <0x20000000 0x10000000>; > + clocks = <&cpg CPG_MOD 83>; > + power-domains = <&cpg>; > + interrupts = <GIC_SPI 445 IRQ_TYPE_LEVEL_HIGH>; > + #address-cells = <1>; > + #size-cells = <0>; > + > + flash@0 { > + compatible = "jedec,spi-nor"; > + reg = <0>; > + spi-max-frequency = <40000000>; > + > + partitions { > + compatible = "fixed-partitions"; > + #address-cells = <1>; > + #size-cells = <1>; > + > + partition@0000000 { > + label = "u-boot"; > + reg = <0x00000000 0x80000>; > + }; > + }; > + }; > + > + # This example is for "External Address Space Read Mode" > + spibsc: spi@1f800000 { > + compatible = "renesas,r7s9210-spibsc"; > + reg = <0x1f800000 0x100>, <0x20000000 0x10000000>; > + clocks = <&cpg CPG_MOD 83>; > + power-domains = <&cpg>; > + interrupts = <GIC_SPI 445 IRQ_TYPE_LEVEL_HIGH>; > + #address-cells = <1>; > + #size-cells = <0>; > + }; > + flash@20000000 { This does not describe the hardware topology: the flash node should be a subnode of the spibsc node, as it relies on the spibsc being clocked. I think when using: spibsc: spi@1f800000 { compatible = "renesas,r7s9210-spibsc", "simple-pm-bus"; reg = <0x1f800000 0x100>; clocks = <&cpg CPG_MOD 83>; power-domains = <&cpg>; interrupts = <GIC_SPI 445 IRQ_TYPE_LEVEL_HIGH>; #address-cells = <1>; #size-cells = <1>; ranges = <0 0x20000000 0x10000000>; flash@0 { ... }; }; and applying "[PATCH] mtd: maps: physmap: Add minimal Runtime PM support"[1], the memory-mapped case should work, without your spibsc driver. Of course, you still need your driver for using the FLASH in SPI mode. > + compatible = "mtd-rom"; > + probe-type = "direct-mapped"; > + reg = <0x20000000 0x4000000>; > + bank-width = <4>; > + device-width = <1>; > + #address-cells = <1>; > + #size-cells = <1>; 1> + > + partition@80000 { > + label ="uboot_env"; > + reg = <0x00080000 0x010000>; > + read-only; > + }; > + }; [1] https://lore.kernel.org/linux-mtd/20191209134823.13330-1-geert+renesas@xxxxxxxxx/ Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
