On Tue, Jan 30, 2018 at 10:11:02AM +0100, Filip Matijević wrote: > Hi, > > On 01/30/2018 09:53 AM, Pavel Machek wrote: > > On Tue 2018-01-30 09:34:46, Ladislav Michl wrote: > >> On Tue, Jan 30, 2018 at 12:33:01AM +0100, Pavel Machek wrote: > >>> On Tue 2018-01-30 00:20:31, Ladislav Michl wrote: > >>>> On Tue, Jan 30, 2018 at 12:05:39AM +0100, Pavel Machek wrote: > >>>>> > >>>>> This adds device tree support to tlv320dac33.c. > >>>>> > >>>>> Signed-off-by: Pavel Machek <pavel@xxxxxx> > >>>>> > >>>>> diff --git a/Documentation/devicetree/bindings/sound/tlv320dac33.txt b/Documentation/devicetree/bindings/sound/tlv320dac33.txt > >>>>> new file mode 100644 > >>>>> index 0000000..6cbd311 > >>>>> --- /dev/null > >>>>> +++ b/Documentation/devicetree/bindings/sound/tlv320dac33.txt > >>>>> @@ -0,0 +1,32 @@ > >>>>> +Texas Instruments - tlv320dac33 Codec module > >>>>> + > >>>>> +The tlv320dac33 serial control bus communicates through I2C protocols. > >>>>> + > >>>>> +Required properties: > >>>>> + > >>>>> +- compatible - "ti,tlv320dac33" > >>>>> +- reg - I2C slave address > >>>>> + > >>>>> +Optional properties: > >>>>> + > >>>>> +- power-gpios - gpio pin to power the device, active high > >>>> > >>>> While driver used gpio in platform data, isn't it more likely > >>>> regulator which powers device? > >>> > >>> power-gpios = <&gpio2 28 0>; /* gpio_60 */ > >>> > >>> Looks like GPIO to me -- example is from Nokia N9. So this appears to > >>> be correct. > >> > >> Device datasheet doesn't list any pin which looks like "power-gpio" > >> http://www.ti.com/lit/ds/symlink/tlv320dac32.pdf > >> Unfortunately I do not know much about N9, but was able to find Nokia 5610 > >> scheme to get clue how could be tlv320dac33 hardwired (see page 2): > >> http://mastermobile.spb.ru/service/nokia_5610_rm-242_service_schematics.pdf > >> Here AVDD is powered by LP3985 voltage regulator which is enabled using > >> VEN pin which might be connected to gpio. Or there could be completely > >> different voltage regulator with different controls. And since Linux > >> already has voltage regulator class, lets not limit ourselves to gpio > >> pins. > > > > Well, notice I'm converting existing driver to device tree. And that > > one already has GPIO dependency. It is possible that more work needs > > to be done there, but that should not be a reason to delay this. Feel > > free to help. Adding DT properties that need to be maintained for compatibility reasons is a bad idea and very good reason to delay merging unfinished stuff. And meanwhile it turned out it is not power-gpio :) > According to N9 schematics > http://www.s-manuals.com/manuals/phone/nokia/nokia_n9_rm-696_service_schematics_v1.pdf > it's in fact GPIO pin that is connected to reset line (labeled > CODEC_RST). So calling it "power" might be misleading, but the driver > code is quite clear as it labels that GPIO as "tlv320dac33 reset" Thanks a lot! So now it is clear that gpio is connected to codec's nRESET pin, therefore "reset-gpios" property seems reasonable here. ladis -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
