lkml.org 
[lkml]   [2010]   [Nov]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/2] of/phylib: Use device tree properties to initialize Marvell PHYs.
On 11/17/2010 03:54 PM, David Daney wrote:
> Some aspects of PHY initialization are board dependent, things like
> indicator LED connections and some clocking modes cannot be determined
> by probing. The dev_flags element of struct phy_device can be used to
> control these things if an appropriate value can be passed from the
> Ethernet driver. We run into problems however if the PHY connections
> are specified by the device tree. There is no way for the Ethernet
> driver to know what flags it should pass.
>
> If we are using the device tree, the struct phy_device will be
> populated with the device tree node corresponding to the PHY, and we
> can extract extra configuration information from there.
>
> The next question is what should the format of that information be?
> It is highly device specific, and the device tree representation
> should not be tied to any arbitrary kernel defined constants. A
> straight forward representation is just to specify the exact bits that
> should be set using the "marvell,reg-init" property:
>
> phy5: ethernet-phy@5 {
> reg =<5>;
> device_type = "ethernet-phy";
> marvell,reg-init =
> <0x00030010 0x5777>, /* Reg 3,16<- 0x5777 */
> <0x00030011 0x00aa>, /* Reg 3,17<- 0x00aa */
> <0x00030012 0x4105>, /* Reg 3,18<- 0x4105 */
> <0x00030013 0x0060>; /* Reg 3,19<- 0x0060 */
> <0x00020015 0x00300000>; /* clear bits 4..5 of Reg 2,21 */

Well, of course these mask bits are reversed. That last line should
really be:

<0x00020015 0xffcf0000>; /* clear bits 4..5 of Reg 2,21 */

> };
>
> The Marvell PHYs have a page select register at register 22 (0x16), we
> can specify any register by its page and register number. These are
> encoded in the high and low parts of the first word. The second word
> contains a mask and value to be ORed in its high and low parts.
> property, the PHY initialization is unchanged.
[...]

David Daney


\
 
 \ /
  Last update: 2010-11-18 01:03    [from the cache]
©2003-2011 Jasper Spaans