Re: [PATCH RFC 1/3] DT: add binding for MXS regulator

Hi Mark,

Am 09.09.2014 19:59, schrieb Mark Rutland:

On Sun, Sep 07, 2014 at 12:37:47PM +0100, Stefan Wahren wrote:

quoted

This patch adds the Device tree bindings for the Freescale MXS on-chip
regulators.

Signed-off-by: Stefan Wahren <redacted>
---
  .../bindings/regulator/mxs-regulator.txt           | 38 ++++++++++++++++++++++
  1 file changed, 38 insertions(+)
  create mode 100644 Documentation/devicetree/bindings/regulator/mxs-regulator.txt

diff --git a/Documentation/devicetree/bindings/regulator/mxs-regulator.txt b/Documentation/devicetree/bindings/regulator/mxs-regulator.txt
new file mode 100644
index 0000000..c3226cc
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/mxs-regulator.txt

@@ -0,0 +1,38 @@
+MXS regulators
+
+Required node properties:
+- compatible: Should be "fsl,<soc>-power", where soc is "imx23" or "imx28"
+- reg: Offset and length of the register set for the device

We require #address-cells and #size-cells if the child nodes have reg
entries.

okay.

quoted

+
+Required regulator properties:
+- compatible: Must be "fsl,mxs-regulator"
+- reg: Offset of the register set for the regulator

Is this the offset or the absolute physical address?

The example seems to be absolute.

You are right, the description is wrong.

quoted

+- mxs-max-reg-val: Maximum value of this register

What does this even mean? What's the format?

Is this not implied by standard properties like regulator-max-microvolt?

Unfortunately not as long the step size in microvolt isn't defined. The 
parameter defines the register value in hex corresponding to 
regulator-max-microvolt.

step size = (regulator-max-microvolt - regulator-min-microvolt) / 
mxs-max-reg-val

May be i missed or understand something wrong?

quoted

+Optional regulator properties:
+- mxs-default-microvolt: initial voltage of the regulator

Why is this necessary?

The original driver from Freescale set the MX28 regulator vddio to 3.38 
V during registering. I think that is ugly to implement in the driver 
part, so i add a more general property in the devicetree binding.

Mark.

Stefan
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