Re: [PATCH v10 1/2] dt-bindings: spi: Add schema for Cadence QSPI Controller driver

"Ramuthevar, Vadivel MuruganX" <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx> · Tue, 25 Feb 2020 15:38:12 +0800

Hi,

On 25/2/2020 2:41 PM, Vignesh Raghavendra wrote:

On 25/02/20 11:54 am, Ramuthevar, Vadivel MuruganX wrote:
Hi Rob,

      Thank you for the review comments...

On 24/2/2020 11:54 PM, Rob Herring wrote:
On Tue, Feb 18, 2020 at 8:29 PM Ramuthevar,Vadivel MuruganX
<vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx> wrote:
From: Ramuthevar Vadivel Murugan
<vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx>
Cc the DT list if you want this reviewed.
Sorry,  next patch will add DT list in CC.
Add dt-bindings documentation for Cadence-QSPI controller to support
spi based flash memories.

Signed-off-by: Ramuthevar Vadivel Murugan
<vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx>
---
   .../devicetree/bindings/spi/cdns,qspi-nor.yaml     | 147
+++++++++++++++++++++
   1 file changed, 147 insertions(+)
   create mode 100644
Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml

diff --git a/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
new file mode 100644
index 000000000000..1a4d6e8d0d0b
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
@@ -0,0 +1,147 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/spi/cdns,qspi-nor.yaml#";
+$schema: "http://devicetree.org/meta-schemas/core.yaml#";
+
+title: Cadence QSPI Flash Controller support
+
+maintainers:
+  - Ramuthevar Vadivel Murugan
<vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx>
+
+allOf:
+  - $ref: "spi-controller.yaml#"
+
+description: |
+  Binding Documentation for Cadence QSPI controller,This controller is
+  present in the Intel LGM, Altera SoCFPGA and TI SoCs and this driver
+  has been tested On Intel's LGM SoC.
+
+  - compatible : should be one of the following:
+        Generic default - "cdns,qspi-nor".
+        For TI 66AK2G SoC - "ti,k2g-qspi", "cdns,qspi-nor".
+        For TI AM654 SoC  - "ti,am654-ospi", "cdns,qspi-nor".
+        For Intel LGM SoC - "intel,lgm-qspi", "cdns,qspi-nor".
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+        - enum:
+           - ti,k2g-qspi
+        - const: cdns,qspi-nor
+
+      - items:
+        - enum:
+           - ti,am654-ospi
+        - const: cdns,qspi-nor
+
+      - items:
+        - enum:
+           - intel,lgm-qspi
+        - const: cdns,qspi-nor
+
+      - items:
+        - const: cdns,qspi-nor
+
+  reg:
+    maxItems: 2
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  cdns,fifo-depth:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Size of the data FIFO in words.
A 4GB fifo is valid? Add some constraints.
128 is valid, will update.
Nope, the width of this field is 8bits -> 256 bytes 

correct me if I am wrong, the width of this field is 4bits -> 128 bytes 
(based on QUAD mode) .

+
+  cdns,fifo-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Bus width of the data FIFO in bytes.
Add some constraints.
4 is valid , will fix it.
+
+  cdns,trigger-address:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      32-bit indirect AHB trigger address.
+
+  cdns,rclk-en:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Flag to indicate that QSPI return clock is used to latch the
read data
+      rather than the QSPI clock. Make sure that QSPI return clock
is populated
+      on the board before using this property.
+
+# subnode's properties
+patternProperties:
+  "^.*@[0-9a-fA-F]+$":
+    type: object
+    description:
+      flash device uses the subnodes below defined properties.
+
+  cdns,read-delay:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Delay for read capture logic, in clock cycles.
4 billion clock delay is valid?
based on the ref_clk , will add it.
+
+  cdns,tshsl-ns:
+    $ref: /schemas/types.yaml#/definitions/uint32
You can drop this, anything with a standard unit suffix already has a
type.
sure , will drop it.
+    description: |
+      Delay in nanoseconds for the length that the master mode chip
select
+      outputs are de-asserted between transactions.
Constraints...?
50ns, will add it.

This really depends on the input clk:

Clock Delay for Chip Select Deassert:

Delay in master reference clocks for the length that the master mode

chip select outputs are de-asserted between transactions The

minimum delay is always SCLK period to ensure the chip select is

never re-asserted within an SCLK period.

I don't see a easy way of verifying constraints in yaml.

Same applies for below 3 properties as well.

Thank you vignesh for  the detailed explanation.

Regards
Vadivel
Regards
Vignesh

Regards
Vadivel
+
+  cdns,tsd2d-ns:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Delay in nanoseconds between one chip select being de-activated
+      and the activation of another.
+
+  cdns,tchsh-ns:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Delay in nanoseconds between last bit of current transaction and
+      deasserting the device chip select (qspi_n_ss_out).
+
+  cdns,tslch-ns:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Delay in nanoseconds between setting qspi_n_ss_out low and
+      first bit transfer.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - cdns,fifo-depth
+  - cdns,fifo-width
+  - cdns,trigger-address
+
+examples:
+  - |
+    qspi: spi@ff705000 {
+          compatible = "cdns,qspi-nor";
+          #address-cells = <1>;
+          #size-cells = <0>;
+          reg = <0xff705000 0x1000>,
+                <0xffa00000 0x1000>;
+          interrupts = <0 151 4>;
+          clocks = <&qspi_clk>;
+          cdns,fifo-depth = <128>;
+          cdns,fifo-width = <4>;
+          cdns,trigger-address = <0x00000000>;
+
+          flash0: n25q00@0 {
+              compatible = "jedec,spi-nor";
+              reg = <0x0>;
+              cdns,read-delay = <4>;
+              cdns,tshsl-ns = <50>;
+              cdns,tsd2d-ns = <50>;
+              cdns,tchsh-ns = <4>;
+              cdns,tslch-ns = <4>;
+          };
+    };
+
--
2.11.0







