Messages in this thread | | | Date | Wed, 20 Aug 2014 14:16:49 -0600 | From | Stephen Warren <> | Subject | Re: [PATCH v2 1/5] of: Add descriptions of thermtrip properties to Tegra PMC bindings |
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On 08/13/2014 06:41 AM, Mikko Perttunen wrote: > Hardware-triggered thermal reset requires configuring the I2C > reset procedure. This configuration is read from the device tree, > so document the relevant properties in the binding documentation.
> diff --git a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-pmc.txt b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-pmc.txt
> +Hardware-triggered thermal reset: > +On Tegra30, Tegra114 and Tegra124, if the 'i2c-thermtrip' subnode exists, > +hardware-triggered thermal reset will be enabled.
"will be enabled" sounds like SW behaviour, whereas DT is suppose to describe HW, and leave SW to define its own behaviour. I would suggest:
Optional sub-nodes: i2c-thermtrip: Describes how to power off the system in the event of a thermal emergency.
> +Required properties for hardware-triggered thermal reset (inside 'i2c-thermtrip'):
Simpler might be:
Required properties for i2c-thermtrip node:
> +- nvidia,pmu : Phandle to power management unit / PMIC handling poweroff > +- nvidia,reg-addr : I2C register address to write poweroff command to > +- nvidia,reg-data : Poweroff command to write to PMU
Why are both the PMU/PMIC phandle and the register address/data required? I thought the purpose of having the phandle was to allow the register address and data to be queried from the PMU/PMIC driver.
To me, it seems much simpler to get rid of the phandle and just hard-code the I2C bus number, address, and data into this node, rather than having to go query it from the PMU/PMIC driver, then find the I2C controller, then query it for its ID (and hope that all HW modules that talk to I2C controllers directly use the same numbering scheme...)
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