On November 6, 2017 1:06:30 AM PST, Benjamin Tissoires [off-list ref] wrote:

Hi Rob,

On Nov 01 2017 or thereabouts, Rob Herring wrote:

quoted

On Tue, Oct 31, 2017 at 11:03:16AM +0800, Lin Huang wrote:

quoted

Document a "reset" and "assert-reset-us", it can be used for
driver control reset property. And reuse post-power-on-delay-ms
for deassert reset delay.

"dt-bindings: input: " for the subject please.

quoted

Signed-off-by: Lin Huang <redacted>
---
 Documentation/devicetree/bindings/input/hid-over-i2c.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git

a/Documentation/devicetree/bindings/input/hid-over-i2c.txt
b/Documentation/devicetree/bindings/input/hid-over-i2c.txt

quoted

quoted

index 28e8bd8..6ab0eed 100644

--- a/Documentation/devicetree/bindings/input/hid-over-i2c.txt
+++ b/Documentation/devicetree/bindings/input/hid-over-i2c.txt

@@ -31,7 +31,9 @@ device-specific compatible properties, which

should be used in addition to the

quoted

quoted

 
 - vdd-supply: phandle of the regulator that provides the supply

voltage.

quoted

quoted

 - post-power-on-delay-ms: time required by the device after

enabling its regulators

quoted

quoted

-  before it is ready for communication. Must be used with

'vdd-supply'.

quoted

quoted

+  or deassert reset pin before it is ready for communication.
+- reset: phandle of the gpio that provides for hid reset pin.

The kernel api takes "reset", but the property is "reset-gpios".

In the same way the generic regulator interface handles vdd-supply, is
there any generic OF handling of reset lines? As far as I can tell,
there are 97 references of reset-gpios in my tree, and I wonder if all
the matching drivers need to rewrite the same code to set the reset
line
on power on/off.

I am worried because here, 1/2 writes "arbitrary" 0 and 1 to the gpios,
and nothing prevent a manufacturer to invert the required voltages on
the reset lines, meaning there will be a need for a new OF property.

1and 0 are logical high and low here. Gpiod API takes care of converting to the proper polarity.


Thanks.

-- 
Dmitry