Re: [PATCH v4 06/10] dt-bindings: mtd: update STM32 FMC2 NAND controller documentation

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Hi Rob,

On 5/14/20 5:00 PM, Rob Herring wrote:
On Wed, May 06, 2020 at 11:11:15AM +0200, Christophe Kerello wrote:
These bindings can be used on SOCs where the FMC2 NAND controller is
in standalone. In case that the FMC2 embeds 2 controllers (an external
bus controller and a raw NAND controller), the register base and the
clock will be defined in the parent node. It is the reason why the
register base address and the clock are now optional.

Signed-off-by: Christophe Kerello <christophe.kerello@xxxxxx>
---
  .../devicetree/bindings/mtd/st,stm32-fmc2-nand.yaml   | 19 ++++++++++---------
  1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/Documentation/devicetree/bindings/mtd/st,stm32-fmc2-nand.yaml b/Documentation/devicetree/bindings/mtd/st,stm32-fmc2-nand.yaml
index b059267..68fac1a 100644
--- a/Documentation/devicetree/bindings/mtd/st,stm32-fmc2-nand.yaml
+++ b/Documentation/devicetree/bindings/mtd/st,stm32-fmc2-nand.yaml
@@ -18,13 +18,15 @@ properties:
reg:
      items:
-      - description: Registers
+      - description: Registers (optional)

The only thing that can be optional are the last entries. You have to do
a 'oneOf' with 6 entries and 7 entries.

Ok, so the way to describe the reg property in my case should be:
       reg:
         oneOf:
           - description: FMC2 embeds the NFC controller in standalone.
             items:
               - description: Registers
               - description: Chip select 0 data
               - description: Chip select 0 command
               - description: Chip select 0 address space
               - description: Chip select 1 data
               - description: Chip select 1 command
               - description: Chip select 1 address space

           - description: FMC2 embeds the NFC controller and the EBI
               controller.
             items:
               - description: Chip select 0 data
               - description: Chip select 0 command
               - description: Chip select 0 address space
               - description: Chip select 1 data
               - description: Chip select 1 command
               - description: Chip select 1 address space


And where's your new compatible string for this different h/w?

From NFC controller point of view, it is the same HW.
In the case that we have 2 controllers embedded, the register base is shared. The NFC driver will check at probe time the compatible string of its parent node. In case that it is "st,stm32mp1-fmc2-ebi", then the driver will find the register base in the parent node (EBI node), otherwise it will find it in the NFC node. Is it better to have 2 compatible strings (one for each reg description) than checking the parent's compatible string and have only one compatible string?

Regards,
Christophe Kerello.


        - description: Chip select 0 data
        - description: Chip select 0 command
        - description: Chip select 0 address space
        - description: Chip select 1 data
        - description: Chip select 1 command
        - description: Chip select 1 address space
+    minItems: 6
+    maxItems: 7
interrupts:
      maxItems: 1
@@ -61,7 +63,6 @@ required:
    - compatible
    - reg
    - interrupts
-  - clocks
examples:
    - |
@@ -77,13 +78,13 @@ examples:
              <0x81000000 0x1000>,
              <0x89010000 0x1000>,
              <0x89020000 0x1000>;
-            interrupts = <GIC_SPI 48 IRQ_TYPE_LEVEL_HIGH>;
-            dmas = <&mdma1 20 0x10 0x12000a02 0x0 0x0>,
-                   <&mdma1 20 0x10 0x12000a08 0x0 0x0>,
-                   <&mdma1 21 0x10 0x12000a0a 0x0 0x0>;
-            dma-names = "tx", "rx", "ecc";
-            clocks = <&rcc FMC_K>;
-            resets = <&rcc FMC_R>;
+      interrupts = <GIC_SPI 48 IRQ_TYPE_LEVEL_HIGH>;
+      dmas = <&mdma1 20 0x2 0x12000a02 0x0 0x0>,
+             <&mdma1 20 0x2 0x12000a08 0x0 0x0>,
+             <&mdma1 21 0x2 0x12000a0a 0x0 0x0>;
+      dma-names = "tx", "rx", "ecc";
+      clocks = <&rcc FMC_K>;
+      resets = <&rcc FMC_R>;
        #address-cells = <1>;
        #size-cells = <0>;
--
1.9.1




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