Messages in this thread | | | Date | Thu, 11 May 2023 11:12:04 +0200 | From | Miquel Raynal <> | Subject | Re: [PATCH v3 6/6] mtd: rawnand: meson: rename node for chip select |
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Hi Arseniy,
avkrasnov@sberdevices.ru wrote on Thu, 11 May 2023 11:59:07 +0300:
> On 10.05.2023 23:53, Miquel Raynal wrote: > > Hello Martin, Miquel > > > Hi Martin & Arseniy, > > > > martin.blumenstingl@googlemail.com wrote on Wed, 10 May 2023 22:40:37 > > +0200: > > > >> Hello Arseniy, > >> > >> On Wed, May 10, 2023 at 1:13 PM Arseniy Krasnov > >> <AVKrasnov@sberdevices.ru> wrote: > >>> > >>> This renames node with values for chip select from "reg" to "cs". It is > >>> needed because when OTP access is enabled on the attached storage, MTD > >>> subsystem registers this storage in the NVMEM subsystem. NVMEM in turn > >>> tries to use "reg" node in its own manner, supposes that it has another > >>> layout. All of this leads to device initialization failure. > >> In general: if we change the device-tree interface (in this case: > >> replacing a "reg" with a "cs" property) the dt-bindings have to be > >> updated as well. > > > > True, and I would add, bindings should not be broken. > > I see, that's true. That is bad way to change bindings. > > > > >> Documentation/devicetree/bindings/mtd/nand-controller.yaml and > >> Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml show > >> that the chip select of a NAND chip is specified with a "reg" > >> property. > > > > All NAND controller binding expect the chip-select to be in the > > 'reg' property, very much like a spi device would use reg to store the > > cs as well: the reg property tells you how you address the device. > > > > I also fully agree with Martin's comments below. Changing reg is likely > > a wrong approach :) > > > >> Also the code has to be backwards compatible with old .dtbs. > >> > >>> Example: > >>> > >>> [...] nvmem mtd0-user-otp: nvmem: invalid reg on /soc/bus@ffe00000/... > >>> [...] mtd mtd0: Failed to register OTP NVMEM device > >>> [...] meson-nand ffe07800.nfc: failed to register MTD device: -22 > >>> [...] meson-nand ffe07800.nfc: failed to init NAND chips > >>> [...] meson-nand: probe of ffe07800.nfc failed with error -22 > >> This is odd - can you please share your definition of the &nfc node? > > Sure, here it is: > > mtd_nand: nfc@7800 { > compatible = "amlogic,meson-axg-nfc"; > ... > nand@0 { > reg = <0>; > }; > } > > I checked, that 'nand_set_flash_node()' is called with 'nand@0' and i suppose > that it is correct (as You mentioned below). But, 'nvmem_add_cells_from_of()' is called > with parent: 'nfc@7800', then it iterates over its childs, e.g. 'nand@0' and thus i get such > situation. I guess, that 'nvmem_add_cells_from_of()' must be called with 'nand@0' ?
We recently had issues with nvmem parsing, but I believe a mainline kernel should now be perfectly working on this regard. What version of the Linux kernel are you using?
Thanks, Miquèl
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