Hi Boris On Wed, Oct 3, 2018 at 11:27 PM Boris Brezillon <boris.brezillon@xxxxxxxxxxx> wrote: > > On Wed, 3 Oct 2018 21:38:58 +0200 > Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx> wrote: > > > Add documentation for gpio-addr-flash. This binding allow creating > > flash devices that are paged using GPIOs. > > > > Cc: devicetree@xxxxxxxxxxxxxxx > > Reviewed-by: Rob Herring <robh@xxxxxxxxxx> > > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx> > > --- > > .../bindings/mtd/gpio-addr-flash.txt | 54 +++++++++++++++++++ > > 1 file changed, 54 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > > > diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > new file mode 100644 > > index 000000000000..5006a26e1753 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt > > @@ -0,0 +1,54 @@ > > +Memory Mapped flash with some address lines addressed using GPIOs > > + > > +Handle the case where a flash device is mostly addressed using physical > > +line and supplemented by GPIOs. This way you can hook up say a 8MiB flash > > +to a 2MiB memory range and use the GPIOs to select a particular range. > > + > > + - compatible : "cfi-gpio-addr-flash" > > + - reg : Address range of the mtd chip that is memory mapped, this is, > > + on the previous example 2MiB. > > + - bank-width : Width (in bytes) of the bank. Equal to the > > + device width times the number of interleaved chips. > > + - gpios: List of GPIO specifiers that will be used to address the MSBs address > > + lines. The order goes from LSB to MSB. > > + - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip > > + is going to be probed. If omitted, assumed to be equal to "cfi_probe". > > Looks like other bindings are encoding the probe type in the > compatible [1][2], and we should probably follow what's been done by > others. If I understood it right, they are special cases of physmap_of_core.c https://elixir.bootlin.com/linux/v4.18.11/source/drivers/mtd/maps/physmap_of_core.c#L242 The driver that handles the compatible is physmap_of_core.c, and afaik multiple drivers with the same compatible string is a very bad idea. We can convert the driver to something like Versatile or gemini, but then we will not support platform devices btw, the binding that I am used is used by: https://elixir.bootlin.com/linux/v4.18.11/source/drivers/mtd/maps/physmap_of_core.c#L91 Yes, I know is obsolete Tomorrow morning I will try to address your comments, test in hw and resend Thanks > > > + - #address-cells, #size-cells : Must be present if the device has > > + sub-nodes representing partitions (see below). In this case > > + both #address-cells and #size-cells must be equal to 1. > > + > > +The device tree may optionally contain sub-nodes describing partitions of the > > +address space. Check partition.txt for more details. > > + > > +Example: > > + > > + flash@300000 { > > + #address-cells = <1>; > > + #size-cells = <1>; > > You should not have the #address-cells and #size-cells props defined at > this level, it's done in the partitions node already. > > > + compatible = "cfi-gpio-addr-flash"; > > + bank-width = <2>; > > + reg = < 0x00300000 0x00200000 >; > > + gpios = <&gpio_0 3 0>, <&gpio_0 4 0>; > > + partitions { > > + compatible = "fixed-partitions"; > > + #address-cells = <1>; > > + #size-cells = <1>; > > + > > + partition@0 { > > + reg = < 0x0 0x200000 >; > > + label = "Golden Bitstream"; > > + }; > > + partition@200000 { > > + reg = < 0x200000 0x200000 >; > > + label = "User Bitstream"; > > + }; > > + partition@400000 { > > + reg = < 0x400000 0x200000 >; > > + label = "V4L Controls"; > > + }; > > + partition@600000 { > > + reg = < 0x600000 0x200000 >; > > + label = "Production Data"; > > + }; > > + } > > + } ; > > [1]https://elixir.bootlin.com/linux/latest/source/Documentation/devicetree/bindings/mtd/cortina,gemini-flash.txt > [2]https://elixir.bootlin.com/linux/latest/source/Documentation/devicetree/bindings/mtd/arm-versatile.txt -- Ricardo Ribalda
