diff mbox series

[v2,2/2] devicetree: i2c-hid: Add reset property

Message ID 1509418996-25348-2-git-send-email-hl@rock-chips.com
State Changes Requested, archived
Headers show
Series None | expand

Commit Message

Lin Huang Oct. 31, 2017, 3:03 a.m. UTC
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.

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

Comments

Rob Herring (Arm) Nov. 1, 2017, 10:02 p.m. UTC | #1
On Tue, Oct 31, 2017 at 11:03:16AM +0800, Lin Huang wrote:
> 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.

> 
> Signed-off-by: Lin Huang <hl@rock-chips.com>
> ---
>  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
> 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
>  
>  - vdd-supply: phandle of the regulator that provides the supply voltage.
>  - post-power-on-delay-ms: time required by the device after enabling its regulators
> -  before it is ready for communication. Must be used with 'vdd-supply'.
> +  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".

And it's not just a phandle typically.

> +- assert-reset-us: the device require reset assert time.
>  
>  Example:
>  
> -- 
> 2.7.4
> 
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Brian Norris Nov. 4, 2017, 4:35 a.m. UTC | #2
On Mon, Oct 30, 2017 at 8:03 PM, Lin Huang <hl@rock-chips.com> wrote:
> 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.
>
> Signed-off-by: Lin Huang <hl@rock-chips.com>
> ---
>  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
> 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
>
>  - vdd-supply: phandle of the regulator that provides the supply voltage.
>  - post-power-on-delay-ms: time required by the device after enabling its regulators
> -  before it is ready for communication. Must be used with 'vdd-supply'.
> +  or deassert reset pin before it is ready for communication.
> +- reset: phandle of the gpio that provides for hid reset pin.
> +- assert-reset-us: the device require reset assert time.

If there was any point in adding the device-specific description
around "wacom,w9013"...then you should probably mention these
properties there too. The idea was to document possible properties
here (where you're adding them already), and to note the property
names under the devices (or so far, just 1 device) that support them.
Or IOW, you need an addition like this:

 - compatible:
   * "wacom,w9013" (Wacom W9013 digitizer). Supports:
     - vdd-supply
     - post-power-on-delay-ms
+    - reset-gpios
+    - assert-reset-us

Brian
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Lin Huang Nov. 6, 2017, 1 a.m. UTC | #3
On Saturday, November 04, 2017 12:35 PM, Brian Norris wrote:
> On Mon, Oct 30, 2017 at 8:03 PM, Lin Huang <hl@rock-chips.com> wrote:
>> 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.
>>
>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>> ---
>>   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
>> 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
>>
>>   - vdd-supply: phandle of the regulator that provides the supply voltage.
>>   - post-power-on-delay-ms: time required by the device after enabling its regulators
>> -  before it is ready for communication. Must be used with 'vdd-supply'.
>> +  or deassert reset pin before it is ready for communication.
>> +- reset: phandle of the gpio that provides for hid reset pin.
>> +- assert-reset-us: the device require reset assert time.
> If there was any point in adding the device-specific description
> around "wacom,w9013"...then you should probably mention these
> properties there too. The idea was to document possible properties
> here (where you're adding them already), and to note the property
> names under the devices (or so far, just 1 device) that support them.
> Or IOW, you need an addition like this:
>
>   - compatible:
>     * "wacom,w9013" (Wacom W9013 digitizer). Supports:
>       - vdd-supply
>       - post-power-on-delay-ms
> +    - reset-gpios
> +    - assert-reset-us
  Okay, got it, will fix it next version.
>
> Brian
>
>
>


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Benjamin Tissoires Nov. 6, 2017, 9:06 a.m. UTC | #4
Hi Rob,

On Nov 01 2017 or thereabouts, Rob Herring wrote:
> On Tue, Oct 31, 2017 at 11:03:16AM +0800, Lin Huang wrote:
> > 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.
> 
> > 
> > Signed-off-by: Lin Huang <hl@rock-chips.com>
> > ---
> >  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
> > 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
> >  
> >  - vdd-supply: phandle of the regulator that provides the supply voltage.
> >  - post-power-on-delay-ms: time required by the device after enabling its regulators
> > -  before it is ready for communication. Must be used with 'vdd-supply'.
> > +  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.

Cheers,
Benjamin

> 
> And it's not just a phandle typically.
> 
> > +- assert-reset-us: the device require reset assert time.
> >  
> >  Example:
> >  
> > -- 
> > 2.7.4
> > 
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Dmitry Torokhov Nov. 6, 2017, 4:10 p.m. UTC | #5
On November 6, 2017 1:06:30 AM PST, Benjamin Tissoires <benjamin.tissoires@redhat.com> wrote:
>Hi Rob,
>
>On Nov 01 2017 or thereabouts, Rob Herring wrote:
>> On Tue, Oct 31, 2017 at 11:03:16AM +0800, Lin Huang wrote:
>> > 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.
>> 
>> > 
>> > Signed-off-by: Lin Huang <hl@rock-chips.com>
>> > ---
>> >  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
>> > 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
>> >  
>> >  - vdd-supply: phandle of the regulator that provides the supply
>voltage.
>> >  - post-power-on-delay-ms: time required by the device after
>enabling its regulators
>> > -  before it is ready for communication. Must be used with
>'vdd-supply'.
>> > +  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.
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/input/hid-over-i2c.txt b/Documentation/devicetree/bindings/input/hid-over-i2c.txt
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
 
 - vdd-supply: phandle of the regulator that provides the supply voltage.
 - post-power-on-delay-ms: time required by the device after enabling its regulators
-  before it is ready for communication. Must be used with 'vdd-supply'.
+  or deassert reset pin before it is ready for communication.
+- reset: phandle of the gpio that provides for hid reset pin.
+- assert-reset-us: the device require reset assert time.
 
 Example: