From: Cristian Cozzolino <cristian_ci@protonmail.com>
Document Novatek NT35532-based DSI display panel.
Signed-off-by: Cristian Cozzolino <cristian_ci@protonmail.com>
---
.../bindings/display/panel/novatek,nt35532.yaml | 66 ++++++++++++++++++++++
MAINTAINERS | 5 ++
2 files changed, 71 insertions(+)
diff --git a/Documentation/devicetree/bindings/display/panel/novatek,nt35532.yaml b/Documentation/devicetree/bindings/display/panel/novatek,nt35532.yaml
new file mode 100644
index 000000000000..de11cce83b40
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/novatek,nt35532.yaml
@@ -0,0 +1,66 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/novatek,nt35532.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Novatek NT35532-based DSI display panels
+
+maintainers:
+ - Cristian Cozzolino <cristian_ci@protonmail.com>
+
+allOf:
+ - $ref: panel-common.yaml#
+
+properties:
+ compatible:
+ const: novatek,nt35532
+
+ reg:
+ maxItems: 1
+
+ backlight: true
+ reset-gpios: true
+
+ vsn-supply:
+ description: negative voltage supply for analog circuits
+ vsp-supply:
+ description: positive voltage supply for analog circuits
+
+ port: true
+
+required:
+ - compatible
+ - reg
+ - reset-gpios
+ - vsn-supply
+ - vsp-supply
+ - port
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+
+ dsi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ panel@0 {
+ compatible = "novatek,nt35532";
+ reg = <0>;
+
+ backlight = <&pmi8950_wled>;
+ reset-gpios = <&tlmm 61 GPIO_ACTIVE_LOW>;
+ vsn-supply = <&ibb>;
+ vsp-supply = <&lab>;
+
+ port {
+ panel_in: endpoint {
+ remote-endpoint = <&dsi0_out>;
+ };
+ };
+ };
+ };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 61bf550fd37c..12243feb0b27 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8139,6 +8139,11 @@ T: git https://gitlab.freedesktop.org/drm/misc/kernel.git
F: Documentation/devicetree/bindings/display/panel/novatek,nt35510.yaml
F: drivers/gpu/drm/panel/panel-novatek-nt35510.c
+DRM DRIVER FOR NOVATEK NT35532 PANELS
+M: Cristian Cozzolino <cristian_ci@protonmail.com>
+S: Maintained
+F: Documentation/devicetree/bindings/display/panel/novatek,nt35532.yaml
+
DRM DRIVER FOR NOVATEK NT35560 PANELS
M: Linus Walleij <linusw@kernel.org>
S: Maintained
--
2.52.0On 08/03/2026 16:52, Cristian Cozzolino via B4 Relay wrote: > + > + backlight: true > + reset-gpios: true > + > + vsn-supply: > + description: negative voltage supply for analog circuits Blank line > + vsp-supply: > + description: positive voltage supply for analog circuits Both are odd. Datasheet says vci, vddi, vddam and optional avdd, avee. There is no VSN and VSP. Otherwise please point the page in datasheet or some schematics. Best regards, Krzysztof
On Sunday, March 8th, 2026 at 17:13, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> > + vsp-supply:
> > + description: positive voltage supply for analog circuits
>
> Both are odd. Datasheet says vci, vddi, vddam and optional avdd, avee.
>
> There is no VSN and VSP. Otherwise please point the page in datasheet or
> some schematics.
>
> Best regards,
> Krzysztof
>
I'm not sure about that. Writing panel dt-bindings has been based pretty mostly on vendor devicetree - which also describes somehow the panel and makes that working with the final product released to the market - so I've to necessarily consider that.
Then, I could agree that vendor devicetree might be not compliant with upstream rules and could possibly make mistakes with describing the hardware, so I'd like to find a way to describe that in a more proper way, according to upstream rules.
That said, vendor devicetree describes lists four power supplies for DSI: 'vdd', 'vddio', 'lab' and 'ibb' (which have the following property names, respectively, in qcom,mdss_dsi_ctrl node: 'vdd-supply', 'vddio-supply', 'lab-supply' and 'ibb-supply'.
Two of these are related to ds/controller (apparently, 'vddio' should match VDDI power supply in NT35532 datasheet.
The remaining two supplies are related to panel ('lab' and 'ibb'). These ones are two 'external ' regulators ('external' from NT35532 perspective), which provide power supply to display, located in the qcom PMIC (in this case, that should be PMI8950). WRT to power supply names described in the bindings ('vsp-supply' and 'vsn-supply') are the same as 'lab-supply' and 'ibb-supply', just named differently in the vendor devicetrees.
Usage of 'vsp'/'vsn' naming for power supply properties is grounded on they commonly being used at upstream (different panel bindings make use of these properties), on one side, and also described on schematics of devices with the same hardware configuration (LCD_VSN and LCD_VSP), on the other.
In the meantime, I've found out schematics for 'xiaomi-mido' (another MSM8953 device) - a variant of this device is shipped with a panel also using NT35532 IC (just like my device) - and LCD_VSN/LCD_VSP are clearly shown there too.
I couldn't find much more information about the display on my device and the only resources available about that are those listed above, as of today. In light of my reply, I ask if it is still necessary to describe, in the bindings, power supply properties properties not used currently in the board DTS file.
Regards,
Cristian.
On 09/03/2026 15:52, cristian_ci wrote:
> On Sunday, March 8th, 2026 at 17:13, Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
>>> + vsp-supply:
>>> + description: positive voltage supply for analog circuits
>>
>> Both are odd. Datasheet says vci, vddi, vddam and optional avdd, avee.
>>
>> There is no VSN and VSP. Otherwise please point the page in datasheet or
>> some schematics.
>>
>> Best regards,
>> Krzysztof
>>
>
> I'm not sure about that. Writing panel dt-bindings has been based pretty mostly on vendor devicetree - which also describes somehow the panel and makes that working with the final product released to the market - so I've to necessarily consider that.
> Then, I could agree that vendor devicetree might be not compliant with upstream rules and could possibly make mistakes with describing the hardware, so I'd like to find a way to describe that in a more proper way, according to upstream rules.
>
> That said, vendor devicetree describes lists four power supplies for DSI: 'vdd', 'vddio', 'lab' and 'ibb' (which have the following property names, respectively, in qcom,mdss_dsi_ctrl node: 'vdd-supply', 'vddio-supply', 'lab-supply' and 'ibb-supply'.
> Two of these are related to ds/controller (apparently, 'vddio' should match VDDI power supply in NT35532 datasheet.
>
> The remaining two supplies are related to panel ('lab' and 'ibb'). These ones are two 'external ' regulators ('external' from NT35532 perspective), which provide power supply to display, located in the qcom PMIC (in this case, that should be PMI8950). WRT to power supply names described in the bindings ('vsp-supply' and 'vsn-supply') are the same as 'lab-supply' and 'ibb-supply', just named differently in the vendor devicetrees.
>
> Usage of 'vsp'/'vsn' naming for power supply properties is grounded on they commonly being used at upstream (different panel bindings make use of these properties), on one side, and also described on schematics of devices with the same hardware configuration (LCD_VSN and LCD_VSP), on the other.
>
> In the meantime, I've found out schematics for 'xiaomi-mido' (another MSM8953 device) - a variant of this device is shipped with a panel also using NT35532 IC (just like my device) - and LCD_VSN/LCD_VSP are clearly shown there too.
>
> I couldn't find much more information about the display on my device and the only resources available about that are those listed above, as of today. In light of my reply, I ask if it is still necessary to describe, in the bindings, power supply properties properties not used currently in the board DTS file.
Please wrap your answers so this will be possible to parse.
You write bindings matching the hardware and for the hardware, not for
the downstream code. You cannot add supplies which do not exist
regardless what some vendor wrote somewhere and yes, you must describe
all known supplies for this device, especially that datasheet is
available publicly.
Best regards,
Krzysztof
Cristian
Sent with Proton Mail secure email.
On Monday, March 9th, 2026 at 16:08, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> On 09/03/2026 15:52, cristian_ci wrote:
> > On Sunday, March 8th, 2026 at 17:13, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >
> >>> + vsp-supply:
> >>> + description: positive voltage supply for analog circuits
> >>
> >> Both are odd. Datasheet says vci, vddi, vddam and optional avdd, avee.
> >>
> >> There is no VSN and VSP. Otherwise please point the page in datasheet or
> >> some schematics.
> >>
> >> Best regards,
> >> Krzysztof
> >>
> >
> > I'm not sure about that. Writing panel dt-bindings has been based pretty mostly on vendor devicetree - which also describes somehow the panel and makes that working with the final product released to the market - so I've to necessarily consider that.
> > Then, I could agree that vendor devicetree might be not compliant with upstream rules and could possibly make mistakes with describing the hardware, so I'd like to find a way to describe that in a more proper way, according to upstream rules.
> >
> > That said, vendor devicetree describes lists four power supplies for DSI: 'vdd', 'vddio', 'lab' and 'ibb' (which have the following property names, respectively, in qcom,mdss_dsi_ctrl node: 'vdd-supply', 'vddio-supply', 'lab-supply' and 'ibb-supply'.
> > Two of these are related to ds/controller (apparently, 'vddio' should match VDDI power supply in NT35532 datasheet.
> >
> > The remaining two supplies are related to panel ('lab' and 'ibb'). These ones are two 'external ' regulators ('external' from NT35532 perspective), which provide power supply to display, located in the qcom PMIC (in this case, that should be PMI8950). WRT to power supply names described in the bindings ('vsp-supply' and 'vsn-supply') are the same as 'lab-supply' and 'ibb-supply', just named differently in the vendor devicetrees.
> >
> > Usage of 'vsp'/'vsn' naming for power supply properties is grounded on they commonly being used at upstream (different panel bindings make use of these properties), on one side, and also described on schematics of devices with the same hardware configuration (LCD_VSN and LCD_VSP), on the other.
> >
> > In the meantime, I've found out schematics for 'xiaomi-mido' (another MSM8953 device) - a variant of this device is shipped with a panel also using NT35532 IC (just like my device) - and LCD_VSN/LCD_VSP are clearly shown there too.
> >
> > I couldn't find much more information about the display on my device and the only resources available about that are those listed above, as of today. In light of my reply, I ask if it is still necessary to describe, in the bindings, power supply properties properties not used currently in the board DTS file.
>
> Please wrap your answers so this will be possible to parse.
>
> You write bindings matching the hardware and for the hardware, not for
> the downstream code. You cannot add supplies which do not exist
> regardless what some vendor wrote somewhere
Vendor has also described the hardware by storing information (by including info
about panel too) directly inside the device itself (/sys/firmware/fdt).
Though vendor devicetree could possibly contain mistakes, I guess I've to trust vendor
devicetree (also for the reasons explained in my last reply).
> and yes, you must describe
> all known supplies for this device, especially that datasheet is
> available publicly.
Based on what you said, the following questions have raised:
- have properties (mentioned by you) be defined
(apart 'vddi', which most likely is actually 'vddio-supply',
already defined within mdss_dsi0 node) outside of 'panel' node?
(and related to dsi/controller rather than panel, instead)
- have those properties (mentioned by you) set as 'optional'
in the bindings, rather than set as 'required'?
(since panel works without most of them defined in the
board DTS file)
> Best regards,
> Krzysztof
>
On 10/03/2026 18:48, cristian_ci wrote:
>
>
>
>
> Cristian
>
> Sent with Proton Mail secure email.
>
> On Monday, March 9th, 2026 at 16:08, Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
>> On 09/03/2026 15:52, cristian_ci wrote:
>>> On Sunday, March 8th, 2026 at 17:13, Krzysztof Kozlowski <krzk@kernel.org> wrote:
>>>
>>>>> + vsp-supply:
>>>>> + description: positive voltage supply for analog circuits
>>>>
>>>> Both are odd. Datasheet says vci, vddi, vddam and optional avdd, avee.
>>>>
>>>> There is no VSN and VSP. Otherwise please point the page in datasheet or
>>>> some schematics.
>>>>
>>>> Best regards,
>>>> Krzysztof
>>>>
>>>
>>> I'm not sure about that. Writing panel dt-bindings has been based pretty mostly on vendor devicetree - which also describes somehow the panel and makes that working with the final product released to the market - so I've to necessarily consider that.
>>> Then, I could agree that vendor devicetree might be not compliant with upstream rules and could possibly make mistakes with describing the hardware, so I'd like to find a way to describe that in a more proper way, according to upstream rules.
>>>
>>> That said, vendor devicetree describes lists four power supplies for DSI: 'vdd', 'vddio', 'lab' and 'ibb' (which have the following property names, respectively, in qcom,mdss_dsi_ctrl node: 'vdd-supply', 'vddio-supply', 'lab-supply' and 'ibb-supply'.
>>> Two of these are related to ds/controller (apparently, 'vddio' should match VDDI power supply in NT35532 datasheet.
>>>
>>> The remaining two supplies are related to panel ('lab' and 'ibb'). These ones are two 'external ' regulators ('external' from NT35532 perspective), which provide power supply to display, located in the qcom PMIC (in this case, that should be PMI8950). WRT to power supply names described in the bindings ('vsp-supply' and 'vsn-supply') are the same as 'lab-supply' and 'ibb-supply', just named differently in the vendor devicetrees.
>>>
>>> Usage of 'vsp'/'vsn' naming for power supply properties is grounded on they commonly being used at upstream (different panel bindings make use of these properties), on one side, and also described on schematics of devices with the same hardware configuration (LCD_VSN and LCD_VSP), on the other.
>>>
>>> In the meantime, I've found out schematics for 'xiaomi-mido' (another MSM8953 device) - a variant of this device is shipped with a panel also using NT35532 IC (just like my device) - and LCD_VSN/LCD_VSP are clearly shown there too.
>>>
>>> I couldn't find much more information about the display on my device and the only resources available about that are those listed above, as of today. In light of my reply, I ask if it is still necessary to describe, in the bindings, power supply properties properties not used currently in the board DTS file.
>>
>> Please wrap your answers so this will be possible to parse.
>>
>> You write bindings matching the hardware and for the hardware, not for
>> the downstream code. You cannot add supplies which do not exist
>> regardless what some vendor wrote somewhere
>
> Vendor has also described the hardware by storing information (by including info
> about panel too) directly inside the device itself (/sys/firmware/fdt).
Vendor does not care about rules of DT thus puts there completely fake
information just to make their drivers working
.
> Though vendor devicetree could possibly contain mistakes, I guess I've to trust vendor
> devicetree (also for the reasons explained in my last reply).
These are not vendor's mistakes. This is deliberate WRONG information.
Sorry, I am not going to keep discussing each property based what vendor
wrote.
Open datasheet which I said is public.
>
>> and yes, you must describe
>> all known supplies for this device, especially that datasheet is
>> available publicly.
>
> Based on what you said, the following questions have raised:
>
> - have properties (mentioned by you) be defined
> (apart 'vddi', which most likely is actually 'vddio-supply',
> already defined within mdss_dsi0 node) outside of 'panel' node?
You are mixing devices. We do not talk about vddio supply in dsi node.
We talk about THIS device, so open this device datasheet and read it.
> (and related to dsi/controller rather than panel, instead)
>
> - have those properties (mentioned by you) set as 'optional'
> in the bindings, rather than set as 'required'?
Why? How device can work without power? Datasheet mentioned which
supplies can be optional, e.g. grounded or wired to the same source of
supply.
> (since panel works without most of them defined in the
> board DTS file)
Best regards,
Krzysztof
On Tuesday, March 10th, 2026 at 21:06, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> On 10/03/2026 18:48, cristian_ci wrote:
> > On Monday, March 9th, 2026 at 16:08, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >
> >> On 09/03/2026 15:52, cristian_ci wrote:
> >>> On Sunday, March 8th, 2026 at 17:13, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >>>
> >>>>> + vsp-supply:
> >>>>> + description: positive voltage supply for analog circuits
> >>>>
> >>>> Both are odd. Datasheet says vci, vddi, vddam and optional avdd, avee.
> >>>>
> >>>> There is no VSN and VSP. Otherwise please point the page in datasheet or
> >>>> some schematics.
> >>>>
> >>>> Best regards,
> >>>> Krzysztof
> >>>>
> >>>
> >>> I'm not sure about that. Writing panel dt-bindings has been based pretty mostly on vendor devicetree - which also describes somehow the panel and makes that working with the final product released to the market - so I've to necessarily consider that.
> >>> Then, I could agree that vendor devicetree might be not compliant with upstream rules and could possibly make mistakes with describing the hardware, so I'd like to find a way to describe that in a more proper way, according to upstream rules.
> >>>
> >>> That said, vendor devicetree describes lists four power supplies for DSI: 'vdd', 'vddio', 'lab' and 'ibb' (which have the following property names, respectively, in qcom,mdss_dsi_ctrl node: 'vdd-supply', 'vddio-supply', 'lab-supply' and 'ibb-supply'.
> >>> Two of these are related to ds/controller (apparently, 'vddio' should match VDDI power supply in NT35532 datasheet.
> >>>
> >>> The remaining two supplies are related to panel ('lab' and 'ibb'). These ones are two 'external ' regulators ('external' from NT35532 perspective), which provide power supply to display, located in the qcom PMIC (in this case, that should be PMI8950). WRT to power supply names described in the bindings ('vsp-supply' and 'vsn-supply') are the same as 'lab-supply' and 'ibb-supply', just named differently in the vendor devicetrees.
> >>>
> >>> Usage of 'vsp'/'vsn' naming for power supply properties is grounded on they commonly being used at upstream (different panel bindings make use of these properties), on one side, and also described on schematics of devices with the same hardware configuration (LCD_VSN and LCD_VSP), on the other.
> >>>
> >>> In the meantime, I've found out schematics for 'xiaomi-mido' (another MSM8953 device) - a variant of this device is shipped with a panel also using NT35532 IC (just like my device) - and LCD_VSN/LCD_VSP are clearly shown there too.
> >>>
> >>> I couldn't find much more information about the display on my device and the only resources available about that are those listed above, as of today. In light of my reply, I ask if it is still necessary to describe, in the bindings, power supply properties properties not used currently in the board DTS file.
> >>
> >> Please wrap your answers so this will be possible to parse.
> >>
> >> You write bindings matching the hardware and for the hardware, not for
> >> the downstream code. You cannot add supplies which do not exist
> >> regardless what some vendor wrote somewhere
> >
> > Vendor has also described the hardware by storing information (by including info
> > about panel too) directly inside the device itself (/sys/firmware/fdt).
>
> Vendor does not care about rules of DT thus puts there completely fake
> information just to make their drivers working
> .
I'm not sure what that statement is based on in the specific case of
the panel I'm actually testing. A set of clues (some of which were also mentioned
in my first reply some days ago) point out that rimob's panel is really supplied by
two regulators part of PMIC [1]. Not only for this reason, I do not have
enough solid reasons, after all, to consider vendor data about the panel mounted in
this device (rimob) as not decently reliable, so I cannot ignore them, at least.
[1] https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/regulator/qcom-labibb-regulator.yaml
> > Though vendor devicetree could possibly contain mistakes, I guess I've to trust vendor
> > devicetree (also for the reasons explained in my last reply).
>
> These are not vendor's mistakes. This is deliberate WRONG information.
>
> Sorry, I am not going to keep discussing each property based what vendor
> wrote.
>
> Open datasheet which I said is public.
(Note: datasheet is indeed easily available but not publicly, since
it has been released under NDA agreement)
> >
> >> and yes, you must describe
> >> all known supplies for this device, especially that datasheet is
> >> available publicly.
> >
> > Based on what you said, the following questions have raised:
> >
> > - have properties (mentioned by you) be defined
> > (apart 'vddi', which most likely is actually 'vddio-supply',
> > already defined within mdss_dsi0 node) outside of 'panel' node?
>
> You are mixing devices. We do not talk about vddio supply in dsi node.
> We talk about THIS device, so open this device datasheet and read it.
I've further inspected the datasheet again (but I've also looked at
other novatek based panels dt-bindings and datasheets, in order to
better figure out what is the actual relationship between the
first and the second ones, more in detail). BTW, I've started doing
tests, by making changes to nt35532 dt-bindings: I've replaced
vsp/vsn supplies with avdd/avee (which are not optional,
they are required to make my display unit to work, actually) mentioned
in the datasheet (but both they rely actually on labibb
regulators - indeed, vendor dt names them 'lab-supply' and
'ibb-supply') and added vci, vddi and vddam too (but I've not included
'vddam' supply into 'required' properties, since my panel unit doesn't
make use of that, in order to work and I can't omit that in panel
node (just like 'backlight' property). Though I've added vddi-supply
to panel dt-bindings and DTS board file, at the same time I've also
left vddio-supply in dsi node (even if they rely on same l6 regulator).
With such dt-bindings and DTS board configuration, the panel still
initializes and just works like before, and I've not noticed a
different behaviour, compared to when I was using the previous
board DTS (the one with vsn/vsp supplies).
> > (and related to dsi/controller rather than panel, instead)
> >
> > - have those properties (mentioned by you) set as 'optional'
> > in the bindings, rather than set as 'required'?
>
> Why? How device can work without power? Datasheet mentioned which
> supplies can be optional, e.g. grounded or wired to the same source of
> supply.
Actually, the device was not working without power: required power
supplies had been defined in the previous dt-bindings
(vsn/vsp supplies). My idea, about the fact that panel was working,
is that my unit needs positive and analog input analog power, which
labibb regulators satisfy. That said, I'm not still convinced that the
new power supplies properties (wich I've also tested on actual
hardware), based on nt35532 datasheet, are enough to satisfy
upstream rules about dt-bindings. Should I show my current changes
to dt-bindings?
> > (since panel works without most of them defined in the
> > board DTS file)
>
>
> Best regards,
> Krzysztof
>
On 13/03/2026 09:26, cristian_ci wrote:
>
> On Tuesday, March 10th, 2026 at 21:06, Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
>> On 10/03/2026 18:48, cristian_ci wrote:
>>> On Monday, March 9th, 2026 at 16:08, Krzysztof Kozlowski <krzk@kernel.org> wrote:
>>>
>>>> On 09/03/2026 15:52, cristian_ci wrote:
>>>>> On Sunday, March 8th, 2026 at 17:13, Krzysztof Kozlowski <krzk@kernel.org> wrote:
>>>>>
>>>>>>> + vsp-supply:
>>>>>>> + description: positive voltage supply for analog circuits
>>>>>>
>>>>>> Both are odd. Datasheet says vci, vddi, vddam and optional avdd, avee.
>>>>>>
>>>>>> There is no VSN and VSP. Otherwise please point the page in datasheet or
>>>>>> some schematics.
>>>>>>
>>>>>> Best regards,
>>>>>> Krzysztof
>>>>>>
>>>>>
>>>>> I'm not sure about that. Writing panel dt-bindings has been based pretty mostly on vendor devicetree - which also describes somehow the panel and makes that working with the final product released to the market - so I've to necessarily consider that.
>>>>> Then, I could agree that vendor devicetree might be not compliant with upstream rules and could possibly make mistakes with describing the hardware, so I'd like to find a way to describe that in a more proper way, according to upstream rules.
>>>>>
>>>>> That said, vendor devicetree describes lists four power supplies for DSI: 'vdd', 'vddio', 'lab' and 'ibb' (which have the following property names, respectively, in qcom,mdss_dsi_ctrl node: 'vdd-supply', 'vddio-supply', 'lab-supply' and 'ibb-supply'.
>>>>> Two of these are related to ds/controller (apparently, 'vddio' should match VDDI power supply in NT35532 datasheet.
>>>>>
>>>>> The remaining two supplies are related to panel ('lab' and 'ibb'). These ones are two 'external ' regulators ('external' from NT35532 perspective), which provide power supply to display, located in the qcom PMIC (in this case, that should be PMI8950). WRT to power supply names described in the bindings ('vsp-supply' and 'vsn-supply') are the same as 'lab-supply' and 'ibb-supply', just named differently in the vendor devicetrees.
>>>>>
>>>>> Usage of 'vsp'/'vsn' naming for power supply properties is grounded on they commonly being used at upstream (different panel bindings make use of these properties), on one side, and also described on schematics of devices with the same hardware configuration (LCD_VSN and LCD_VSP), on the other.
>>>>>
>>>>> In the meantime, I've found out schematics for 'xiaomi-mido' (another MSM8953 device) - a variant of this device is shipped with a panel also using NT35532 IC (just like my device) - and LCD_VSN/LCD_VSP are clearly shown there too.
>>>>>
>>>>> I couldn't find much more information about the display on my device and the only resources available about that are those listed above, as of today. In light of my reply, I ask if it is still necessary to describe, in the bindings, power supply properties properties not used currently in the board DTS file.
>>>>
>>>> Please wrap your answers so this will be possible to parse.
>>>>
>>>> You write bindings matching the hardware and for the hardware, not for
>>>> the downstream code. You cannot add supplies which do not exist
>>>> regardless what some vendor wrote somewhere
>>>
>>> Vendor has also described the hardware by storing information (by including info
>>> about panel too) directly inside the device itself (/sys/firmware/fdt).
>>
>> Vendor does not care about rules of DT thus puts there completely fake
>> information just to make their drivers working
>> .
>
> I'm not sure what that statement is based on in the specific case of
It's based on years of looking at vendor code.
> the panel I'm actually testing. A set of clues (some of which were also mentioned
> in my first reply some days ago) point out that rimob's panel is really supplied by
> two regulators part of PMIC [1]. Not only for this reason, I do not have
> enough solid reasons, after all, to consider vendor data about the panel mounted in
> this device (rimob) as not decently reliable, so I cannot ignore them, at least.
And I did not disagree that you need regulators and that vendor
correctly wired two of them.
The comments are about naming!
I discussed of using argument of incomplete or not fully correct vendor
code when the true hardware description is available. If the vendor
calls them in vendor DTS "yellow-pony-supply" you are going to use that
argument to write bindings? And then argue that "not sure what that
statement is based on"?
It's obvious - vendor code is crap. There are no VSN and VSP inputs. We
already confirmed that.
You claim that vendor called like that thus you can use them as well is
simply not correct approach.
Best regards,
Krzysztof
On Friday, March 13th, 2026 at 09:32, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> On 13/03/2026 09:26, cristian_ci wrote:
> >
> > On Tuesday, March 10th, 2026 at 21:06, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >
> >> On 10/03/2026 18:48, cristian_ci wrote:
> >>> On Monday, March 9th, 2026 at 16:08, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >>>
> >>>> On 09/03/2026 15:52, cristian_ci wrote:
> >>>>> On Sunday, March 8th, 2026 at 17:13, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >>>>>
> >>>>>>> + vsp-supply:
> >>>>>>> + description: positive voltage supply for analog circuits
> >>>>>>
> >>>>>> Both are odd. Datasheet says vci, vddi, vddam and optional avdd, avee.
> >>>>>>
> >>>>>> There is no VSN and VSP. Otherwise please point the page in datasheet or
> >>>>>> some schematics.
> >>>>>>
> >>>>>> Best regards,
> >>>>>> Krzysztof
> >>>>>>
> >>>>>
> >>>>> I'm not sure about that. Writing panel dt-bindings has been based pretty mostly on vendor devicetree - which also describes somehow the panel and makes that working with the final product released to the market - so I've to necessarily consider that.
> >>>>> Then, I could agree that vendor devicetree might be not compliant with upstream rules and could possibly make mistakes with describing the hardware, so I'd like to find a way to describe that in a more proper way, according to upstream rules.
> >>>>>
> >>>>> That said, vendor devicetree describes lists four power supplies for DSI: 'vdd', 'vddio', 'lab' and 'ibb' (which have the following property names, respectively, in qcom,mdss_dsi_ctrl node: 'vdd-supply', 'vddio-supply', 'lab-supply' and 'ibb-supply'.
> >>>>> Two of these are related to ds/controller (apparently, 'vddio' should match VDDI power supply in NT35532 datasheet.
> >>>>>
> >>>>> The remaining two supplies are related to panel ('lab' and 'ibb'). These ones are two 'external ' regulators ('external' from NT35532 perspective), which provide power supply to display, located in the qcom PMIC (in this case, that should be PMI8950). WRT to power supply names described in the bindings ('vsp-supply' and 'vsn-supply') are the same as 'lab-supply' and 'ibb-supply', just named differently in the vendor devicetrees.
> >>>>>
> >>>>> Usage of 'vsp'/'vsn' naming for power supply properties is grounded on they commonly being used at upstream (different panel bindings make use of these properties), on one side, and also described on schematics of devices with the same hardware configuration (LCD_VSN and LCD_VSP), on the other.
> >>>>>
> >>>>> In the meantime, I've found out schematics for 'xiaomi-mido' (another MSM8953 device) - a variant of this device is shipped with a panel also using NT35532 IC (just like my device) - and LCD_VSN/LCD_VSP are clearly shown there too.
> >>>>>
> >>>>> I couldn't find much more information about the display on my device and the only resources available about that are those listed above, as of today. In light of my reply, I ask if it is still necessary to describe, in the bindings, power supply properties properties not used currently in the board DTS file.
> >>>>
> >>>> Please wrap your answers so this will be possible to parse.
> >>>>
> >>>> You write bindings matching the hardware and for the hardware, not for
> >>>> the downstream code. You cannot add supplies which do not exist
> >>>> regardless what some vendor wrote somewhere
> >>>
> >>> Vendor has also described the hardware by storing information (by including info
> >>> about panel too) directly inside the device itself (/sys/firmware/fdt).
> >>
> >> Vendor does not care about rules of DT thus puts there completely fake
> >> information just to make their drivers working
> >> .
> >
> > I'm not sure what that statement is based on in the specific case of
>
> It's based on years of looking at vendor code.
>
> > the panel I'm actually testing. A set of clues (some of which were also mentioned
> > in my first reply some days ago) point out that rimob's panel is really supplied by
> > two regulators part of PMIC [1]. Not only for this reason, I do not have
> > enough solid reasons, after all, to consider vendor data about the panel mounted in
> > this device (rimob) as not decently reliable, so I cannot ignore them, at least.
>
> And I did not disagree that you need regulators and that vendor
> correctly wired two of them.
>
> The comments are about naming!
>
> I discussed of using argument of incomplete or not fully correct vendor
> code when the true hardware description is available. If the vendor
> calls them in vendor DTS "yellow-pony-supply" you are going to use that
> argument to write bindings? And then argue that "not sure what that
> statement is based on"?
>
> It's obvious - vendor code is crap. There are no VSN and VSP inputs. We
> already confirmed that.
>
> You claim that vendor called like that thus you can use them as well is
> simply not correct approach.
Ok but I don't know if I can submit a v2 series including my new bindings
changes (along with changes for other patches too) or I've to stick with
v1 here, by showing my proposed fix for power supply properties, in order
to address review concerns about bindings, first.
> Best regards,
> Krzysztof
>
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