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Subject[PATCH v2 07/16] dt-bindings: memory-controllers: add canaan k210 sram controller
Date
From: Conor Dooley <conor.dooley@microchip.com>

The k210 U-Boot port has been using the clocks defined in the
devicetree to bring up the board's SRAM, but this violates the
dt-schema. As such, move the clocks to a dedicated node with
the same compatible string & document it.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
I made myself maintainer since I didn't have anywhere else
to point a finger, but I am happy to let someone else take
that on!

The corresponding U-Boot code seems to be:
static int sram_init(void)
{
int ret, i;
const char * const banks[] = { "sram0", "sram1", "aisram" };
ofnode memory;
struct clk clk;

/* Enable RAM clocks */
memory = ofnode_by_compatible(ofnode_null(), "canaan,k210-sram");
if (ofnode_equal(memory, ofnode_null()))
return -ENOENT;

for (i = 0; i < ARRAY_SIZE(banks); i++) {
ret = clk_get_by_name_nodev(memory, banks[i], &clk);
if (ret)
continue;

ret = clk_enable(&clk);
clk_free(&clk);
if (ret)
return ret;
}

return 0;
}

Which, without having the hardware etc, I suspect is likely to keep
working after the move.
---
.../memory-controllers/canaan,k210-sram.yaml | 53 +++++++++++++++++++
1 file changed, 53 insertions(+)
create mode 100644 Documentation/devicetree/bindings/memory-controllers/canaan,k210-sram.yaml

diff --git a/Documentation/devicetree/bindings/memory-controllers/canaan,k210-sram.yaml b/Documentation/devicetree/bindings/memory-controllers/canaan,k210-sram.yaml
new file mode 100644
index 000000000000..837eb65854fc
--- /dev/null
+++ b/Documentation/devicetree/bindings/memory-controllers/canaan,k210-sram.yaml
@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/canaan,k210-sram.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Canaan K210 SRAM memory controller
+
+description: |
+ The Canaan K210 SRAM memory controller is initialised and programmed by
+ firmware, but an OS might want to read its registers for error reporting
+ purposes and to learn about the DRAM topology.
+
+maintainers:
+ - Conor Dooley <conor@kernel.org>
+
+properties:
+ compatible:
+ enum:
+ - canaan,k210-sram
+
+ clocks:
+ minItems: 1
+ items:
+ - description: sram0 clock
+ - description: sram1 clock
+ - description: aisram clock
+
+ clock-names:
+ minItems: 1
+ items:
+ - const: sram0
+ - const: sram1
+ - const: aisram
+
+required:
+ - compatible
+ - clocks
+ - clock-names
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/clock/k210-clk.h>
+ memory-controller {
+ compatible = "canaan,k210-sram";
+ clocks = <&sysclk K210_CLK_SRAM0>,
+ <&sysclk K210_CLK_SRAM1>,
+ <&sysclk K210_CLK_AI>;
+ clock-names = "sram0", "sram1", "aisram";
+ };
+
--
2.36.1
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