On Tuesday, February 15, 2022 8:39 AM, Bjorn Andersson

On Mon 14 Feb 19:04 CST 2022, Jarrett Schultz wrote:

quoted

Jarrett Schultz wrote:

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From: Jarrett Schultz

Rob Herring wrote:

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From: Rob Herring <robh@kernel.org>

On Tue, Dec 21, 2021 at 10:28:23AM -0800, Jarrett Schultz wrote:

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From: Jarrett Schultz <redacted>

+title: Surface Extensible Bootloader for Microsoft Surface Duo
+
+maintainers:
+  - Jarrett Schultz [off-list ref]
+
+description: |
+  Defined to expose information that is used during production
+when
+  device is in manufacturing mode. Some of the information
+included
+  in this imem section is -

If this is onchip sram, we have a binding for that. That's not an MFD.

I now have this driver working with nvmem, but I could not find the
binding that you are talking about here. Could you point me to the

binding?

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Thanks,
Jarrett

Rob,

I followed up with my team members who have let me know that this lies
in DDR rather than SRAM. Could you please point me to the correct
binding to use?

It might be DDR, but it's on-chip and the memory region that you describe is
a region within "imem" - something used for various purposes by Qualcomm,
presumably also in your device. Unfortunately we haven't specified a binding
for "imem", only some of its regions.

Perhaps it would be appropriate to express the entire imem as nvmem, in
addition to the region-specific logic, if that suits you.

Regards,
Bjorn

Bjorn et al.,

This xbl driver was meant to be something simple and the intent was to merge it into the tree with an existing structure. Your suggestion makes sense, and I believe that it could be implemented as a separate patch after this patch with the initial xbl driver has been accepted and merged.

Please let me know what you think,
Jarrett Schultz

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Thanks,
Jarrett

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+    * board_id
+    * battery_present
+    * hw_init_retries
+    * is_customer_mode
+    * is_act_mode
+    * pmic_reset_reason
+    * touch_fw_version
+    * ocp_error_location

nvmem binding doesn't work for describing these fields?

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+  See sysfs documentation for more information.

sysfs? Not relevant to the binding.

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+
+properties:
+  compatible:
+    const: simple-mfd
+
+  reg:
+    maxItems: 1
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - ranges
+  - address-cells
+  - size-cells
+
+examples:
+  - |
+    / {
+        compatible = "foo";
+        model = "foo";

No need to make this the root node with a fake compatible.

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+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        imem@146bf000 {
+          compatible = "simple-mfd";
+          reg = <0x0 0x146bf000 0x0 0x1000>;
+          ranges = <0x0 0x0 0x146bf000 0x1000>;
+          #address-cells = <1>;
+          #size-cells = <1>;
+          status = "okay";

Don't show status in examples.

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+
+          xbl@a94 {
+            compatible = "microsoft,sm8150-surface-duo-xbl";
+            reg = <0xa94 0x100>;
+            status = "okay";
+          };
+        };
+      };

diff --git a/MAINTAINERS b/MAINTAINERS index

13f9a84a617e..5d0ca2a98b57 100644

--- a/MAINTAINERS
+++ b/MAINTAINERS

@@ -12649,6 +12649,13 @@ F:	Documentation/driver-

api/surface_aggregator/clients/dtx.rst

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 F:	drivers/platform/surface/surface_dtx.c
 F:	include/uapi/linux/surface_aggregator/dtx.h

+MICROSOFT SURFACE DUO XBL DRIVER
+M:	Jarrett Schultz [off-list ref]
+L:	linux-arm-msm@vger.kernel.org
+L:	platform-driver-x86@vger.kernel.org
+S:	Supported
+F:

	Documentation/devicetree/bindings/platform/microsoft/surface-

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xbl.yaml

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+
 MICROSOFT SURFACE GPE LID SUPPORT DRIVER
 M:	Maximilian Luz [off-list ref]
 L:	platform-driver-x86@vger.kernel.org
--
2.25.1