Hi,

On Sat, Jan 10, 2015 at 12:20 AM, Gregory CLEMENT
[off-list ref] wrote:

Hi Hans,

On 09/01/2015 16:46, Hans de Goede wrote:

quoted

Hi,

On 09-01-15 11:39, Gregory CLEMENT wrote:

quoted

It is now possible to use a regulator property for each port of the
AHCI controller.

Signed-off-by: Gregory CLEMENT <redacted>
---
  Documentation/devicetree/bindings/ata/ahci-platform.txt | 9 ++++++---
  1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/ata/ahci-platform.txt b/Documentation/devicetree/bindings/ata/ahci-platform.txt
index 4ab09f2202d4..87416d71c758 100644
--- a/Documentation/devicetree/bindings/ata/ahci-platform.txt
+++ b/Documentation/devicetree/bindings/ata/ahci-platform.txt

@@ -37,9 +37,10 @@ Required properties when using sub-nodes:


  Sub-nodes required properties:
-- reg               : the port number
-- phys              : reference to the SATA PHY node
-
+- reg                                       : the port number
+And at least one of the following properties:
+- phys                      : reference to the SATA PHY node
+- target-port<n>-supply     : regulator for SATA target power for port <n>

  Examples:
          sata at ffe08000 {

@@ -68,10 +69,12 @@ With sub-nodes:
             sata0: sata-port at 0 {
                     reg = <0>;
                     phys = <&sata_phy 0>;
+                    target-port0-supply = <&reg_sata0>;
             };

I'm sorry, but I've to NAK this, I did not follow the regulator discussion.,
thinking that it was just about the use of some utility function vs diy or
some such, I had no idea this would impact the dt-binding.

The -port%d- bit is completely unnecessary from a dt pov. Devicetree is
supposed to be OS agnostic, we cannot make the dt-binding ugly just because
the regulator subsys in Linux does not provide the necessary functionality.

I'm afraid you will have to get back to the regulator subsys people and tell
them that we really need an of_regulator_get, so that we can tell the
regulator subsys we want a regulator from a specific of_node.

I didn't cc you especially, but I cc the linux-ide mailing list. The
email was "[PATCH 2/2] regulator: core: Add the device tree version to
the regulator_get family" (see
http://thread.gmane.org/gmane.linux.kernel/1856154).

Mark Brown didn't want a firmware specific interface. The regulator
framework allows associating only a regulator to a device and
currently, at least from the point of view of the device tree, the
port subnodes are not devices. He suggested making the child node
device. However, when I had a look on it, it didn't seem an easy
task. As you know better this code, what do you think of it?

(I added Mark Bronw in CC of this email so he can add more explanation
if needed)

Since the AHCI library code already supports the generic phy subsystem,
with one phy possible for each port node, you could possibly add a
generic phy that just takes a regulator, and hook it up that way.

I don't know if the extra layer of indirection is good or not.
Just offering an alternative.


Regards,
ChenYu

quoted

Please CC me when you re-open the discussion with the regulator people.

Regards,

Hans

--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

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