Hello Stephen,

On Tue, May 27, 2014 at 02:40:15PM -0700, Stephen Boyd wrote:

On 05/24/14 05:48, Mark Brown wrote:

quoted

On Fri, May 23, 2014 at 12:57:17PM -0700, Stephen Boyd wrote:

quoted

 Optional properties:
-- vdd-supply:	supply for Ethernet mac
+- vdd-supply: analog 3.3V supply for Ethernet mac
+- vdd-io-supply: digital 1.8V IO supply for Ethernet mac

So, according to the datasheet I managed to find this device has a
supply VDD_IO (so normally written vdd-io-supply here), some other
supplies which are tied to VDD_IO (so can probably be omitted) and a
supply VDD_A3.3 none of which are optional.  There is an internal
regulator which can be used to drop a higher voltage VDD_IO down for
some of the supplies tied to it but that's essentially a noop from
software as far as I can tell.  None of these supplies are obviously
optional, though I've not read the datasheet in detail so I may have
missed something here.

There is a difference between the supply being optional for the hardware
to work and the need to specify it in the device tree, isn't it? My
expectation is that when it's not specified there is just nothing the
the software needs to care for. 

quoted

That said it looks like this is intended to be a supply for an external
PHY rather than the device itself, but even so my original question
about it being able to operate without power still applies.  Looking at
the code it's certainly not doing any of the handling of a missing
supply that I would associate with using _optional().

I agree, both supplies don't look optional. Unfortunately
efm32gg-dk3750.dts doesn't look to be listing any supply, and this
driver only recently got support for the VDD_A3.3 supply that the omap
board uses (adding Uwe for any comments on efm setup). I presume on

If I read the schematic correctly there is nothing to regulate on the
efm32 dev board. If you want to take a look on the schematic yourself,
it's contained in the documentation package available at
http://www.silabs.com/products/mcu/lowpower/pages/efm32gg-dk3750.aspx .
BDR3201A_A02_sch.pdf, page 3 of 22.

Best regards
Uwe

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Pengutronix e.K.                           | Uwe Kleine-König            |
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