Re: [PATCH v2 2/5] of: Add nvidia,controller-id property to Tegra I2C bindings

From: Stephen Warren
Date: Wed Aug 20 2014 - 16:19:19 EST


On 08/13/2014 06:41 AM, Mikko Perttunen wrote:
Sometimes, hardware blocks want to issue requests to devices
connected to I2C buses by itself. In such case, the bus the
target device resides on must be configured into a register.
For this purpose, each I2C controller has a defined ID known
by the hardware. Add a property for these IDs to the device tree
bindings, so that drivers can know what ID to write to a hardware
register when configuring a block that sends I2C messages autonomously.

diff --git a/Documentation/devicetree/bindings/i2c/nvidia,tegra20-i2c.txt b/Documentation/devicetree/bindings/i2c/nvidia,tegra20-i2c.txt

+Optional properties:
+- nvidia,controller-id: ID of controller when referred to in
+ hardware registers.

I'd prefer to put this information into the thermal trip node, since this represents what ID the PMC uses to communicate with the I2C controller, and there's no absolute guarantee that multiple clients that communicate directly with an I2C controller would use the same numbering scheme.

If that doesn't work, can be at least name this nvidia,pmc-controller-id or nvidia,id-in-pmc so that if there are different numbering schemes, there's a clear path to represent this in different properties without conflicting names?
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