On Mon, Oct 19, 2020 at 9:20 PM Tomasz Figa <tfiga@xxxxxxxxxxxx> wrote: > > On Mon, Oct 19, 2020 at 10:28 AM Sakari Ailus > <sakari.ailus@xxxxxxxxxxxxxxx> wrote: > > > > On Wed, Oct 14, 2020 at 01:48:00PM +0200, Tomasz Figa wrote: > > > On Wed, Oct 14, 2020 at 10:31 AM Sakari Ailus > > > <sakari.ailus@xxxxxxxxxxxxxxx> wrote: > > > > > > > > On Wed, Oct 14, 2020 at 10:10:18AM +0800, Dongchun Zhu wrote: > > > > > Hello Sakari, > > > > > > > > > > Thanks for your timely review. > > > > > > > > > > On Tue, 2020-10-13 at 19:19 +0300, Sakari Ailus wrote: > > > > > > Hi Dongchun, > > > > > > > > > > > > On Tue, Oct 13, 2020 at 09:05:02PM +0800, Dongchun Zhu wrote: > > > > > > > Add YAML device tree binding for OV02A10 CMOS image sensor, and the > > > > > > > relevant MAINTAINERS entries. > > > > > > > > > > > > > > Signed-off-by: Dongchun Zhu <dongchun.zhu@xxxxxxxxxxxx> > > > > > > > --- > > > > > > > .../bindings/media/i2c/ovti,ov02a10.yaml | 162 +++++++++++++++++++++ > > > > > > > MAINTAINERS | 7 + > > > > > > > 2 files changed, 169 insertions(+) > > > > > > > create mode 100644 Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml > > > > > > > > > > > > > > > > > [snip]... > > > > > > > > > > > > + ovti,mipi-clock-voltage: > > > > > > > + description: > > > > > > > + An array of 2-tuples items, and each item consists of link frequency and > > > > > > > + MIPI clock voltage unit like <freq-kHz volt-unit>. Clock voltage unit is > > > > > > > + dependent upon link speed, indicating MIPI transmission speed select that > > > > > > > + controls D-PHY timing setting by adjusting MIPI clock voltage to improve > > > > > > > + the clock driver capability. > > > > > > > + $ref: "/schemas/types.yaml#/definitions/uint32-array" > > > > > > > + minItems: 2 > > > > > > > + default: [390000, 4] > > > > > > > > > > > > Why do you have the link frequency here as well? > > > > > > > > > > > > In principle this does belong to the endpoint as link frequencies are > > > > > > specific to that, but I don't mind; there's just a single port anyway. > > > > > > > > > > > > > > > > This is an optional property which we model as an array of <link speed, > > > > > clock voltage> pairs. An example to have all link speeds up to 390MHz > > > > > use the value 4 for current driver. If one wants to select different > > > > > voltage for different link, they could do so as well. > > > > > > > > If you think you'd need that, then you need to put this to the endpoint. > > > > > > The mipi-clock-voltage property is not a property of the endpoint. The > > > link frequency there does not set the link frequency - it only > > > specifies which link frequency the given voltage should be used for. > > > > If it is not bound to the endpoint --- that specifies the properties of the > > link --- then you could just put it to the driver, couldn't you? > > > > But earlier on, we established that this is specific to a given board, or a > > given link. Endpoints are used to describe connections that a device may > > have to other devices. Therefore their properties are different. > > > > The graph bindings allow for several endpoints on a single physical port, > > some may be disabled in that case. This is admittedly mostly done with > > CSI-2 receivers. > > > > Either way, putting this property to the device may affect how DT source is > > arranged for boards that have this device. Any similar configuration on > > other devices with multiple transmitters or receivers would be in endpoints > > anyway --- because they have to, so I don't see why bindings for this > > device should be different. > > > > If you put it to endpoint, the driver also doesn't need to match the link > > frequencies in kHz and Hz between the two properties, but just use the same > > index for both. > > I agree in general, but I think in this case this is a device-specific > property and the sensor only has 1 CSI-2 interface, so maybe it > doesn't really matter? > > Specifying frequency, voltage pairs is a common practice in other > bindings, such as the OPP bindings, by the way. > > That said, if you insist, I'm fine with this being moved to the > endpoint node too. Is the conclusion that it needs to be moved? Best regards, Tomasz
