Re: [PATCH v2 2/2] Add dt-bindings for Cadence XSPI controller

Konrad Kociolek <konrad@xxxxxxxxxxx> · Wed, 19 Feb 2020 12:30:29 +0100

The 02/05/2020 18:31, Rob Herring wrote:
EXTERNAL MAIL


On Tue, Jan 28, 2020 at 01:43:04PM +0100, Konrad Kociolek wrote:
Add dt-bindings documentation for Cadence XSPI controller to support
SPI based flash memories.

Signed-off-by: Konrad Kociolek <konrad@xxxxxxxxxxx>
---
Changes between initial version and v2:
  - renamed yaml file
  - added missing include

 .../devicetree/bindings/spi/cdns,xspi.yaml         | 166 +++++++++++++++++++++
 1 file changed, 166 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/cdns,xspi.yaml

diff --git a/Documentation/devicetree/bindings/spi/cdns,xspi.yaml b/Documentation/devicetree/bindings/spi/cdns,xspi.yaml
new file mode 100644
index 000000000000..e8c43957fd90
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/cdns,xspi.yaml
@@ -0,0 +1,166 @@
+# SPDX-License-Identifier: (GPL-2.0)

Dual license new bindings:

(GPL-2.0-only OR BSD-2-Clause)

+# Copyright 2020 Cadence
+%YAML 1.2
+---
+$id: "https://urldefense.proofpoint.com/v2/url?u=http-3A__devicetree.org_schemas_spi_cdns-2Cxspi.yaml-23&d=DwIBAg&c=aUq983L2pue2FqKFoP6PGHMJQyoJ7kl3s3GZ-_haXqY&r=G7iI7AW4JEOXbx13Fe5B7uVPtTH6HSiaA_R5uR2HQjY&m=vgq1v6AC47kHEnD4BGadbiavRIW3wUjNWfh5fCNtivI&s=5GznvYUXU7Lk0eHcHCnJAsz0aKwZmZqEsGGo5A9i2l8&e= "
+$schema: "https://urldefense.proofpoint.com/v2/url?u=http-3A__devicetree.org_meta-2Dschemas_core.yaml-23&d=DwIBAg&c=aUq983L2pue2FqKFoP6PGHMJQyoJ7kl3s3GZ-_haXqY&r=G7iI7AW4JEOXbx13Fe5B7uVPtTH6HSiaA_R5uR2HQjY&m=vgq1v6AC47kHEnD4BGadbiavRIW3wUjNWfh5fCNtivI&s=pm5-krCiP_J-P48RO4mlub5ARy9eGOBfV59k8d02Q4g&e= "
+
+title: Cadence XSPI Controller
+
+maintainers:
+  - Konrad Kociolek <konrad@xxxxxxxxxxx>
+
+description: |
+  The XSPI controller allows SPI protocol communication in
+  single, dual, quad or octal wire transmission modes for
+  read/write access to slaves such as SPI-NOR flash.
+

Needs a ref to spi-controller.yaml

+properties:
+  compatible:
+    const: cdns,xspi-nor-fpga
+
+  reg:
+    maxItems: 3
+    description: |
+      Contains three entries, each of which is a tuple consisting of a
+      physical address and length. The first entry is the address and
+      length of the controller register set. The second entry is the
+      address and length of the Slave DMA data port. The third entry is
+      the address and length of auxiliary registers.

Split into 3 descriptions:

items:
 - description: ...
 - description: ...
 - description: ...

With that, drop 'maxItems' as it is implied.

+
+  interrupts:
+    maxItems: 1
+
+  cdns,dqs-last-data-drop:
+    type: boolean
+    description: |
+      This parameter should be set when the Flash Device being used
+      issues data on negative edge of Flash clock and returns them with
+      DQS and the PHY is configured to sample data in DQS mode.
+      If this param is set the controller internally requests this redundant
+      data at the end of the transfer cleaning up the PHY FIFO.
+
+  cdns,phy-data-select-oe-start:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Adjusts the starting point of the DQ pad output enable window.
+      Lower numbers pull the rising edge earlier in time and larger
+      numbers cause the rising edge to be delayed. Each bit changes
+      the output enable time by a 1/2 cycle resolution.
+
+  cdns,phy-data-select-oe-end:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Adjusts the ending point of the DQ pad output enable window.
+      Lower numbers pull the falling edge earlier in time and larger
+      numbers cause the falling edge to be delayed. Each bit changes
+      the output enable time by a 1/2 cycle resolution.
+
+  cdns,phy-dqs-select-oe-start:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Adjusts the starting point of the DQS pad output enable window.
+      Lower numbers pull the rising edge earlier in time and larger
+      numbers cause the rising edge to be delayed. Each bit changes
+      the output enable time by a 1/2 cycle resolution.
+
+  cdns,phy-dqs-select-oe-end:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Adjusts the ending point of the DQS pad output enable window.
+      Lower numbers pull the falling edge earlier in time and larger
+      numbers cause the falling edge to be delayed. Each bit changes
+      the output enable time by a 1/2 cycle resolution.
+
+  cdns,phy-gate-cfg-close:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Normally the gate is closing then all bits of dfi_cebar are high
+      or when dfi_rd_pre_post_amble and rebar_dfi are high. This parameter
+      allows to extend the closing of the DQS gate. Recommended zero.
+
+  cdns,phy-gate-cfg:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Coarse adjust of gate open time. This value is the number of cycles
+      to delay the dfi_rddata_en signal prior to opening the gate in
+      full cycle increments. Decreasing this value pulls the gate earlier
+      in time. This field should be programmed such that the gate signal
+      lands in the valid DQS gate window.
+
+  cdns,phy-rd-del-select:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Defines the read data delay. Holds the number of cycles to delay
+      the dfi_rddata_en signal prior to enabling the read FIFO.
+      After this delay, the read pointers begin incrementing the read FIFO.
+
+  cdns,phy-clk-wr-delay:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Controls the clk_wr delay line which adjusts the write DQ bit
+      timing in 1/256th steps of the clock period in normal DLL
+      locked mode. In bypass mode this field directly programs
+      the number of delay elements.

For all of these, any constraints on the values? default?

+
+  cdns,phy-use-lpbk-dqs:
+    type: boolean
+    description: |
+      This parameter chooses lpbk_dqs to capture data for reads.
+      Instead memory DQS will be used.
+
+  cdns,phy-use-ext-lpbk-dqs:
+    type: boolean
+    description: |
+      This parameter chooses external lpbk_dqs for data capture
+      (lpbk_dqs connected to the lpbk_dqs_IO pad). When not used
+      mem_rebar_pad is used for data read capture.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - cdns,phy-data-select-oe-start
+  - cdns,phy-data-select-oe-end
+  - cdns,phy-dqs-select-oe-start
+  - cdns,phy-dqs-select-oe-end
+  - cdns,phy-gate-cfg-close
+  - cdns,phy-gate-cfg
+  - cdns,phy-rd-del-select
+  - cdns,phy-clk-wr-delay

Is there no sensible default to make these optional?

Those parameters depend on connected flash memory, used FPGA board,
memory adapter and must be adjusted by user, to make memory
communication working.
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    xspi: spi@a0010000 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        compatible = "cdns,xspi-nor-fpga";
+        reg = <0x0 0xa0010000 0x0 0x10000>,
+              <0x0 0xb0000000 0x0 0x10000>,
+              <0x0 0xa0020000 0x0 0x10000>;
+        interrupts = <0 90 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-parent = <&gic>;
+        cdns,dqs-last-data-drop;
+        cdns,phy-data-select-oe-start = <0>;
+        cdns,phy-data-select-oe-end = <4>;
+        cdns,phy-dqs-select-oe-start = <0>;
+        cdns,phy-dqs-select-oe-end = <1>;
+        cdns,phy-gate-cfg-close = <3>;
+        cdns,phy-gate-cfg = <0>;
+        cdns,phy-rd-del-select = <5>;
+        cdns,phy-clk-wr-delay = <64>;
+        cdns,phy-use-lpbk-dqs;
+        cdns,phy-use-ext-lpbk-dqs;
+        mt35xu512@0 {

flash@0

+            compatible = "spi-nor", "micron,mt35xu512";

Wrong order. Most specific first.

+            spi-max-frequency = <75000000>;
+            reg = <0>;
+        };
+        mt35xu512@1 {

flash@1

+            compatible = "spi-nor", "micron,mt35xu512";
+            spi-max-frequency = <75000000>;
+            reg = <1>;
+        };
+    };
--
2.15.0


--
--
Konrad Kociolek






