Re: [PATCH RESEND 02/16] Documentation: dt-bindings: backlight: add TI LMU backlight binding information

Kim, Milo
2015-11-03T07:13:08Z

On 11/3/2015 12:02 AM, Rob Herring wrote:
> On Sun, Nov 1, 2015 at 11:24 PM, Milo Kim <milo.kim@ti.com> wrote:
>> LM3532, LM3631, LM3632, LM3633, LM3695 and LM3697 use common dt-bindings
>> for describing device.
>>
>> Cc: devicetree@vger.kernel.org
>> Cc: Jingoo Han <jingoohan1@gmail.com>
>> Cc: Lee Jones <lee.jones@linaro.org>
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Milo Kim <milo.kim@ti.com>
>> ---
>> .../bindings/video/backlight/ti-lmu-backlight.txt | 67 ++++++++++++++++++++++
>
> Please move to bindings/leds/backlight/

There are backlight bindings under video/backlight. I'd like to know why
this 'led' location is preferred. My guess is most of properties are
from common LED properties. Any other reasons?

>
>> 1 file changed, 67 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/video/backlight/ti-lmu-backlight.txt
>>
>> diff --git a/Documentation/devicetree/bindings/video/backlight/ti-lmu-backlight.txt b/Documentation/devicetree/bindings/video/backlight/ti-lmu-backlight.txt
>> new file mode 100644
>> index 0000000..27b0036
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/video/backlight/ti-lmu-backlight.txt
>> @@ -0,0 +1,67 @@
>> +TI LMU backlight device tree bindings
>> +
>> +Required properties:
>> + - compatible: Should be one of lists below.
>> + "ti,lm3532-backlight"
>> + "ti,lm3631-backlight"
>> + "ti,lm3632-backlight"
>> + "ti,lm3633-backlight"
>> + "ti,lm3695-backlight"
>> + "ti,lm3697-backlight"
>> +
>> +Optional properties:
>> + There are two backlight control mode. One is I2C, the other is PWM mode.
>> + Following properties are only specified in PWM mode.
>> + Please note that LMU backlight device can have only one PWM channel.
>> +
>> + - pwms: OF device-tree PWM specification.
>> + - pwm-names: a list of names for the PWM devices specified in the "pwms"
>> + property.
>> +
>> + For the PWM user nodes, please refer to [1].
>> +
>> +Child nodes:
>> + LMU backlight is represented as sub-nodes of the TI LMU device [2].
>> + So, LMU backlight should have more than one backlight child node.
>> + Each node exactly matches with backlight control bank configuration.
>> + Maximum numbers of child nodes depend on the device.
>> + 1 = LM3631, LM3632, LM3695
>> + 2 = LM3633, LM3697
>> + 3 = LM3532
>> +
>> + Required property of a child node:
>> + - hvled1-used, hvled2-used, hvled3-used:
>> + High voltage backlight strings configuration. Type is <boolean>.
>> + Please describe which output backlight string is used.
>> + Please refer to the datasheets [3].
>
> Use led-sources.

OK.

>
>> +
>> + Optional properties of a child node:
>> + - backlight-name: Name string for backlight device identification.
>> + It is used for creating backlight sysfs,
>> + /sys/class/backlight/<backlight-name>/.
>
> Use label.

Got it.

>
>> + - backlight-max-microamp: Max current setting. Type is <u32>.
>> + Unit is microampere.
>> + Range is from 5000 to 30000.
>
> Use led-max-microamp

OK.

>
>> + - initial-brightness: Backlight initial brightness value. Type is <u32>.
>> + It is set as soon as backlight device is created.
>> + 0 ~ 2047 = LM3631, LM3632, LM3633, LM3695 and LM3697
>> + 0 ~ 255 = LM3532
>
> Use default-brightness-level
>

I'll update the bindings and drivers based on your review. Many thanks!

Best regards,
Milo