On Wed, Jul 13, 2016 at 09:27:31AM +0200, Philipp Zabel wrote:

Am Mittwoch, den 13.07.2016, 10:06 +0800 schrieb Peter Chen:

quoted

Add binding doc for generic power sequence library.

Signed-off-by: Peter Chen <redacted>
---
 .../bindings/power/pwrseq/pwrseq-generic.txt       | 53 ++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt

diff --git a/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
new file mode 100644
index 0000000..186c58c
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt

@@ -0,0 +1,53 @@
+The generic power sequence library
+
+Some hard-wired USB/MMC devices need to do power sequence to let the
+device work normally,

I would replace "to let the device work normally" with "before the
device can be enumerated [on the bus]" here.

Ok.

quoted

 the typical power sequence like: enable USB
+PHY clock, toggle reset pin, etc. But current Linux USB driver
+lacks of such code to do it, it may cause some hard-wired USB devices
+works abnormal or can't be recognized by controller at all. The
+power sequence will be done before this device can be found at USB
+bus.
+
+The power sequence properties is under the device node.
+
+Required properties:
+- power-sequence: this device needs to do power sequence before enumeration

As Joshua pointed out, is this even needed at all?

If no, how we decide whether allocates pwrseq instance through pwrseq
library or not?

-- 

Best Regards,
Peter Chen