[RESEND] [PATCH v2 2/4] dt-bindings: Add jdi lt070me05000 panel bindings

[RESEND] [PATCH v2 2/4] dt-bindings: Add jdi lt070me05000 panel bindings

[Vinay Simha BN]

Add documentation for lt070me05000 panel

Cc: Archit Taneja <archit.taneja@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>

---
v2:
 * incorporated rob herring and thierry reviews
   gpio to gpios, gpio to regulator using fixed regulators
   and pwm backlight is removed, since it is controlled by
   dcs commands
---
 .../bindings/display/panel/jdi,lt070me05000.txt    | 57 ++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt

diff --git a/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
new file mode 100644
index 0000000..613b76f
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
@@ -0,0 +1,57 @@
+JDI model LT070ME05000 1200x1920 7" DSI Panel
+
+Required properties:
+- compatible: should be "jdi,lt070me05000"
+- vddp-supply: phandle of the regulator that provides the supply voltage
+  Power IC supply (3-5V)
+- dcdc_en-supply: phandle of the regulator that provides the supply voltage
+  Power IC supply enable, High active
+- vcc-supply: phandle of the regulator that provides the supply voltage
+  IOVCC , power supply for LCM (1.8V)
+- reset-gpios: phandle of gpio for reset line
+  This should be 8mA, gpio can be configured using mux, pinctrl, pinctrl-names
+  XRES, Reset, Low active
+- enable-gpios: phandle of gpio for enable line
+  LED_EN, LED backlight enable, High active
+
+Example:
+
+	vcc_1p8v: regulator-fixed@2 {
+		compatible = "regulator-fixed";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+		regulator-name = "vcc_1p8v";
+		regulator-type = "voltage";
+		startup-delay-us = <0>;
+		gpio = <&pm8921_gpio 23 GPIO_ACTIVE_HIGH>;
+		enable-active-high;
+		regulator-boot-on;
+	};
+
+	tlmm_pinmux: pinctrl@800000 {
+
+		dsi_panel_pinctrl: dsi-panel-pinctrl {
+			mux {
+				pins = "gpio54";
+				function = "gpio";
+				bias-pull-up;
+				drive-strength = <8>;
+			};
+		};
+	};
+
+	dsi0: qcom,mdss_dsi@4700000 {
+		panel@0 {
+			compatible = "jdi,lt070me05000";
+			reg = <0>;
+			pinctrl-names = "default";
+			pinctrl-0 = <&dsi_panel_pinctrl>;
+
+			vddp-supply = <&pm8921_l17>;
+			dcdc_en-supply = <&pm8921_lvs7>;
+			vcc-supply = <&vcc_1p8v>;
+
+			reset-gpios = <&tlmm_pinmux 54 0>;
+			enable-gpios = <&pm8921_gpio 36 GPIO_ACTIVE_HIGH>;
+		};
+	};
-- 
2.1.2

Re: [RESEND] [PATCH v2 2/4] dt-bindings: Add jdi lt070me05000 panel bindings

[Thierry Reding]

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On Sun, Jul 31, 2016 at 08:45:21PM +0530, Vinay Simha BN wrote:
> Add documentation for lt070me05000 panel
> 
> Cc: Archit Taneja <archit.taneja@gmail.com>
> Cc: John Stultz <john.stultz@linaro.org>
> Cc: Thierry Reding <thierry.reding@gmail.com>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
> Acked-by: Rob Herring <robh@kernel.org>
> 
> ---
> v2:
>  * incorporated rob herring and thierry reviews
>    gpio to gpios, gpio to regulator using fixed regulators
>    and pwm backlight is removed, since it is controlled by
>    dcs commands
> ---
>  .../bindings/display/panel/jdi,lt070me05000.txt    | 57 ++++++++++++++++++++++
>  1 file changed, 57 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
> 
> diff --git a/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
> new file mode 100644
> index 0000000..613b76f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
> @@ -0,0 +1,57 @@
> +JDI model LT070ME05000 1200x1920 7" DSI Panel
> +
> +Required properties:
> +- compatible: should be "jdi,lt070me05000"
> +- vddp-supply: phandle of the regulator that provides the supply voltage
> +  Power IC supply (3-5V)
> +- dcdc_en-supply: phandle of the regulator that provides the supply voltage
> +  Power IC supply enable, High active
> +- vcc-supply: phandle of the regulator that provides the supply voltage
> +  IOVCC , power supply for LCM (1.8V)

I was just going to apply this and wanted to add some information about
how many lanes the panel uses, so I looked at the datasheet linked to in
patch 4/4:

	http://panelone.net/en/7-0-inch/JDI_LT070ME05000_7.0_inch-datasheet

and noticed that the power supplies in the binding here don't match the
ones listed in the datasheet. Granted, the datasheet is somewhat meager,
but it lists the following three input voltages:

	- IOVCC at 1.8 V
	- VDD at 3.0 V
	- VDDP at 3.0 V

This matches in part what the above binding describes, but it's not
quite right, so I'm wondering if the name for dcdc_en-supply came from
the board schematics and reflects the name of the rail on the board
design that provides this rather than the input voltage on the panel.

I think we should follow the names in the panel datasheet so that people
can more easily reference the correct regulators when using this panel
on a different board. I'd suggest:

	- iovcc-supply: phandle of the regulator that supplies power to
	  the IOVCC voltage input (1.8 V)
	- vdd-supply: phandle of the regulator that supplies power to
	  the VDD voltage input (3.0 V)
	- vddp-supply: phandle of the regulator that supplies power to
	  the VDDP voltage input (3.0 V)

Any objections?

Thierry

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Re: [RESEND] [PATCH v2 2/4] dt-bindings: Add jdi lt070me05000 panel bindings

[Vinay Simha]

thierry,

this is the reference pinouts of the panel
http://www.tonylabs.com/wp-content/uploads/LT070ME05000-pinouts.jpg

as you suggest , i will change the vcc-supply,

 - iovcc-supply: phandle of the regulator that supplies power to
          the IOVCC voltage input (1.8 V)

will keep the other two(vddp-supply, dcdc_en-supply) remaining same.

On Wed, Aug 24, 2016 at 5:15 PM, Thierry Reding
<thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On Sun, Jul 31, 2016 at 08:45:21PM +0530, Vinay Simha BN wrote:
>> Add documentation for lt070me05000 panel
>>
>> Cc: Archit Taneja <archit.taneja-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> Cc: John Stultz <john.stultz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>> Cc: Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> Cc: Sumit Semwal <sumit.semwal-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>> Signed-off-by: Vinay Simha BN <simhavcs-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
>>
>> ---
>> v2:
>>  * incorporated rob herring and thierry reviews
>>    gpio to gpios, gpio to regulator using fixed regulators
>>    and pwm backlight is removed, since it is controlled by
>>    dcs commands
>> ---
>>  .../bindings/display/panel/jdi,lt070me05000.txt    | 57 ++++++++++++++++++++++
>>  1 file changed, 57 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
>>
>> diff --git a/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
>> new file mode 100644
>> index 0000000..613b76f
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
>> @@ -0,0 +1,57 @@
>> +JDI model LT070ME05000 1200x1920 7" DSI Panel
>> +
>> +Required properties:
>> +- compatible: should be "jdi,lt070me05000"
>> +- vddp-supply: phandle of the regulator that provides the supply voltage
>> +  Power IC supply (3-5V)
>> +- dcdc_en-supply: phandle of the regulator that provides the supply voltage
>> +  Power IC supply enable, High active
>> +- vcc-supply: phandle of the regulator that provides the supply voltage
>> +  IOVCC , power supply for LCM (1.8V)
>
> I was just going to apply this and wanted to add some information about
> how many lanes the panel uses, so I looked at the datasheet linked to in
> patch 4/4:
>
>         http://panelone.net/en/7-0-inch/JDI_LT070ME05000_7.0_inch-datasheet
>
> and noticed that the power supplies in the binding here don't match the
> ones listed in the datasheet. Granted, the datasheet is somewhat meager,
> but it lists the following three input voltages:
>
>         - IOVCC at 1.8 V
>         - VDD at 3.0 V
>         - VDDP at 3.0 V
>
> This matches in part what the above binding describes, but it's not
> quite right, so I'm wondering if the name for dcdc_en-supply came from
> the board schematics and reflects the name of the rail on the board
> design that provides this rather than the input voltage on the panel.
>
> I think we should follow the names in the panel datasheet so that people
> can more easily reference the correct regulators when using this panel
> on a different board. I'd suggest:
>
>         - iovcc-supply: phandle of the regulator that supplies power to
>           the IOVCC voltage input (1.8 V)
>         - vdd-supply: phandle of the regulator that supplies power to
>           the VDD voltage input (3.0 V)
>         - vddp-supply: phandle of the regulator that supplies power to
>           the VDDP voltage input (3.0 V)
>
> Any objections?
>
> Thierry



-- 
regards,
vinaysimha
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Re: [RESEND] [PATCH v2 2/4] dt-bindings: Add jdi lt070me05000 panel bindings

[Thierry Reding]

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On Wed, Aug 24, 2016 at 05:34:55PM +0530, Vinay Simha wrote:
> thierry,
> 
> this is the reference pinouts of the panel
> http://www.tonylabs.com/wp-content/uploads/LT070ME05000-pinouts.jpg

I can't open that file.

> as you suggest , i will change the vcc-supply,
> 
>  - iovcc-supply: phandle of the regulator that supplies power to
>           the IOVCC voltage input (1.8 V)
> 
> will keep the other two(vddp-supply, dcdc_en-supply) remaining same.

"dcdc_en" sounds to me like it should be a GPIO rather than a regulator.

According to this datasheet:

	http://kb.52solution.com/data/uploads/2016/04/07/3172846545705cc22d050e.pdf

the input voltages are indeed VDD, VDDp and IOVCC, though with slightly
larger tolerances than the previous datasheet. VDD and VDDp can both go
from 3.0 V to 5.0 V. DCDC_EN is indeed an additional GPIO to enable the
VDDp supply.

I think you'd need something along these lines:

	- vdd-supply: LED power supply (3.0-5.0 V)
	- vddp-supply: power IC supply (3.0-5.0 V)
	- iovcc-supply: LCM power supply (1.8 V)
	- dcdc-en-gpios: power IC supply enable
	- led-en-gpios: LED backlight enable

Or perhaps your vddp-supply should be a regulator that's controlled by
the GPIO that you'd put in dcdc-en-gpios. That might work better. That
would leave only led-en-gpios as the only enable GPIOs property, so it
would be okay to keep the name "enable-gpios", I guess.

Thierry

> On Wed, Aug 24, 2016 at 5:15 PM, Thierry Reding
> <thierry.reding@gmail.com> wrote:
> > On Sun, Jul 31, 2016 at 08:45:21PM +0530, Vinay Simha BN wrote:
> >> Add documentation for lt070me05000 panel
> >>
> >> Cc: Archit Taneja <archit.taneja@gmail.com>
> >> Cc: John Stultz <john.stultz@linaro.org>
> >> Cc: Thierry Reding <thierry.reding@gmail.com>
> >> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> >> Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
> >> Acked-by: Rob Herring <robh@kernel.org>
> >>
> >> ---
> >> v2:
> >>  * incorporated rob herring and thierry reviews
> >>    gpio to gpios, gpio to regulator using fixed regulators
> >>    and pwm backlight is removed, since it is controlled by
> >>    dcs commands
> >> ---
> >>  .../bindings/display/panel/jdi,lt070me05000.txt    | 57 ++++++++++++++++++++++
> >>  1 file changed, 57 insertions(+)
> >>  create mode 100644 Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
> >> new file mode 100644
> >> index 0000000..613b76f
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
> >> @@ -0,0 +1,57 @@
> >> +JDI model LT070ME05000 1200x1920 7" DSI Panel
> >> +
> >> +Required properties:
> >> +- compatible: should be "jdi,lt070me05000"
> >> +- vddp-supply: phandle of the regulator that provides the supply voltage
> >> +  Power IC supply (3-5V)
> >> +- dcdc_en-supply: phandle of the regulator that provides the supply voltage
> >> +  Power IC supply enable, High active
> >> +- vcc-supply: phandle of the regulator that provides the supply voltage
> >> +  IOVCC , power supply for LCM (1.8V)
> >
> > I was just going to apply this and wanted to add some information about
> > how many lanes the panel uses, so I looked at the datasheet linked to in
> > patch 4/4:
> >
> >         http://panelone.net/en/7-0-inch/JDI_LT070ME05000_7.0_inch-datasheet
> >
> > and noticed that the power supplies in the binding here don't match the
> > ones listed in the datasheet. Granted, the datasheet is somewhat meager,
> > but it lists the following three input voltages:
> >
> >         - IOVCC at 1.8 V
> >         - VDD at 3.0 V
> >         - VDDP at 3.0 V
> >
> > This matches in part what the above binding describes, but it's not
> > quite right, so I'm wondering if the name for dcdc_en-supply came from
> > the board schematics and reflects the name of the rail on the board
> > design that provides this rather than the input voltage on the panel.
> >
> > I think we should follow the names in the panel datasheet so that people
> > can more easily reference the correct regulators when using this panel
> > on a different board. I'd suggest:
> >
> >         - iovcc-supply: phandle of the regulator that supplies power to
> >           the IOVCC voltage input (1.8 V)
> >         - vdd-supply: phandle of the regulator that supplies power to
> >           the VDD voltage input (3.0 V)
> >         - vddp-supply: phandle of the regulator that supplies power to
> >           the VDDP voltage input (3.0 V)
> >
> > Any objections?
> >
> > Thierry
> 
> 
> 
> -- 
> regards,
> vinaysimha

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Re: [RESEND] [PATCH v2 2/4] dt-bindings: Add jdi lt070me05000 panel bindings

[Vinay Simha]

 - dcdc-en-gpios: power IC supply enable

i cannot make this as gpios, since pm8921_lvs7 is a regulator.
We can make gpio as regulator, but not regulator as gpio.

other option i have to map pm8921_lvs7 to iovcc-supply and pm8921_gpio
23 to dcdc-en-gpios.

Since we do not have nx7 schematic not sure which pins are mapped in
hardware, other than the src code reference. Even in the 3.4 source
code gpio/pin/regulator mappings and naming are not proper in
board-flo-display.c

What is your suggestion?

On Wed, Aug 24, 2016 at 6:02 PM, Thierry Reding
<thierry.reding@gmail.com> wrote:
> On Wed, Aug 24, 2016 at 05:34:55PM +0530, Vinay Simha wrote:
>> thierry,
>>
>> this is the reference pinouts of the panel
>> http://www.tonylabs.com/wp-content/uploads/LT070ME05000-pinouts.jpg
>
> I can't open that file.
>
>> as you suggest , i will change the vcc-supply,
>>
>>  - iovcc-supply: phandle of the regulator that supplies power to
>>           the IOVCC voltage input (1.8 V)
>>
>> will keep the other two(vddp-supply, dcdc_en-supply) remaining same.
>
> "dcdc_en" sounds to me like it should be a GPIO rather than a regulator.
>
> According to this datasheet:
>
>         http://kb.52solution.com/data/uploads/2016/04/07/3172846545705cc22d050e.pdf
>
> the input voltages are indeed VDD, VDDp and IOVCC, though with slightly
> larger tolerances than the previous datasheet. VDD and VDDp can both go
> from 3.0 V to 5.0 V. DCDC_EN is indeed an additional GPIO to enable the
> VDDp supply.
>
> I think you'd need something along these lines:
>
>         - vdd-supply: LED power supply (3.0-5.0 V)
>         - vddp-supply: power IC supply (3.0-5.0 V)
>         - iovcc-supply: LCM power supply (1.8 V)
>         - dcdc-en-gpios: power IC supply enable
>         - led-en-gpios: LED backlight enable
>
> Or perhaps your vddp-supply should be a regulator that's controlled by
> the GPIO that you'd put in dcdc-en-gpios. That might work better. That
> would leave only led-en-gpios as the only enable GPIOs property, so it
> would be okay to keep the name "enable-gpios", I guess.
>
> Thierry
>
>> On Wed, Aug 24, 2016 at 5:15 PM, Thierry Reding
>> <thierry.reding@gmail.com> wrote:
>> > On Sun, Jul 31, 2016 at 08:45:21PM +0530, Vinay Simha BN wrote:
>> >> Add documentation for lt070me05000 panel
>> >>
>> >> Cc: Archit Taneja <archit.taneja@gmail.com>
>> >> Cc: John Stultz <john.stultz@linaro.org>
>> >> Cc: Thierry Reding <thierry.reding@gmail.com>
>> >> Cc: Sumit Semwal <sumit.semwal@linaro.org>
>> >> Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
>> >> Acked-by: Rob Herring <robh@kernel.org>
>> >>
>> >> ---
>> >> v2:
>> >>  * incorporated rob herring and thierry reviews
>> >>    gpio to gpios, gpio to regulator using fixed regulators
>> >>    and pwm backlight is removed, since it is controlled by
>> >>    dcs commands
>> >> ---
>> >>  .../bindings/display/panel/jdi,lt070me05000.txt    | 57 ++++++++++++++++++++++
>> >>  1 file changed, 57 insertions(+)
>> >>  create mode 100644 Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
>> >>
>> >> diff --git a/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
>> >> new file mode 100644
>> >> index 0000000..613b76f
>> >> --- /dev/null
>> >> +++ b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
>> >> @@ -0,0 +1,57 @@
>> >> +JDI model LT070ME05000 1200x1920 7" DSI Panel
>> >> +
>> >> +Required properties:
>> >> +- compatible: should be "jdi,lt070me05000"
>> >> +- vddp-supply: phandle of the regulator that provides the supply voltage
>> >> +  Power IC supply (3-5V)
>> >> +- dcdc_en-supply: phandle of the regulator that provides the supply voltage
>> >> +  Power IC supply enable, High active
>> >> +- vcc-supply: phandle of the regulator that provides the supply voltage
>> >> +  IOVCC , power supply for LCM (1.8V)
>> >
>> > I was just going to apply this and wanted to add some information about
>> > how many lanes the panel uses, so I looked at the datasheet linked to in
>> > patch 4/4:
>> >
>> >         http://panelone.net/en/7-0-inch/JDI_LT070ME05000_7.0_inch-datasheet
>> >
>> > and noticed that the power supplies in the binding here don't match the
>> > ones listed in the datasheet. Granted, the datasheet is somewhat meager,
>> > but it lists the following three input voltages:
>> >
>> >         - IOVCC at 1.8 V
>> >         - VDD at 3.0 V
>> >         - VDDP at 3.0 V
>> >
>> > This matches in part what the above binding describes, but it's not
>> > quite right, so I'm wondering if the name for dcdc_en-supply came from
>> > the board schematics and reflects the name of the rail on the board
>> > design that provides this rather than the input voltage on the panel.
>> >
>> > I think we should follow the names in the panel datasheet so that people
>> > can more easily reference the correct regulators when using this panel
>> > on a different board. I'd suggest:
>> >
>> >         - iovcc-supply: phandle of the regulator that supplies power to
>> >           the IOVCC voltage input (1.8 V)
>> >         - vdd-supply: phandle of the regulator that supplies power to
>> >           the VDD voltage input (3.0 V)
>> >         - vddp-supply: phandle of the regulator that supplies power to
>> >           the VDDP voltage input (3.0 V)
>> >
>> > Any objections?
>> >
>> > Thierry
>>
>>
>>
>> --
>> regards,
>> vinaysimha



-- 
regards,
vinaysimha

Re: [RESEND] [PATCH v2 2/4] dt-bindings: Add jdi lt070me05000 panel bindings

[Thierry Reding]

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On Sun, Jul 31, 2016 at 08:45:21PM +0530, Vinay Simha BN wrote:
[...]
> diff --git a/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
[...]
> +- reset-gpios: phandle of gpio for reset line
> +  This should be 8mA, gpio can be configured using mux, pinctrl, pinctrl-names
> +  XRES, Reset, Low active
> +- enable-gpios: phandle of gpio for enable line
> +  LED_EN, LED backlight enable, High active

This is a little confusing. Shouldn't we rather completely omit any
mention of the polarity of these and let the board design handle this?

If the reset is low active, then I'd expect that to be reflected in the
GPIO specifier of the reset-gpios property, like so:

	panel@0 {
		...
		reset-gpios = <&tlmm_pinmux 54 GPIO_ACTIVE_LOW>;
		...
	};

With that a driver can simply deal with a high active reset, which it
currently doesn't. The problem with the current description is that it
is unclear who's to deal with the polarity. In order for this to work
properly with the current driver you'll have to specify the GPIO as
GPIO_ACTIVE_HIGH, which is not what the binding says it should be.

Thierry

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Re: [RESEND] [PATCH v2 2/4] dt-bindings: Add jdi lt070me05000 panel bindings

[Vinay Simha]

if we do not set the polarity to 8mA, panel will have gibberish display.
(information to set 8mA is available only in
nexus7-msm-flo-3.4-lollipop-release_dsi kernel nx7 release)

i will add this
reset-gpios = <&tlmm_pinmux 54 GPIO_ACTIVE_LOW>;

On Wed, Aug 24, 2016 at 5:26 PM, Thierry Reding
<thierry.reding@gmail.com> wrote:
> On Sun, Jul 31, 2016 at 08:45:21PM +0530, Vinay Simha BN wrote:
> [...]
>> diff --git a/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt
> [...]
>> +- reset-gpios: phandle of gpio for reset line
>> +  This should be 8mA, gpio can be configured using mux, pinctrl, pinctrl-names
>> +  XRES, Reset, Low active
>> +- enable-gpios: phandle of gpio for enable line
>> +  LED_EN, LED backlight enable, High active
>
> This is a little confusing. Shouldn't we rather completely omit any
> mention of the polarity of these and let the board design handle this?
>
> If the reset is low active, then I'd expect that to be reflected in the
> GPIO specifier of the reset-gpios property, like so:
>
>         panel@0 {
>                 ...
>                 reset-gpios = <&tlmm_pinmux 54 GPIO_ACTIVE_LOW>;
>                 ...
>         };
>
> With that a driver can simply deal with a high active reset, which it
> currently doesn't. The problem with the current description is that it
> is unclear who's to deal with the polarity. In order for this to work
> properly with the current driver you'll have to specify the GPIO as
> GPIO_ACTIVE_HIGH, which is not what the binding says it should be.
>
> Thierry



-- 
regards,
vinaysimha

Re: [RESEND] [PATCH v2 2/4] dt-bindings: Add jdi lt070me05000 panel bindings

[Thierry Reding]

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On Wed, Aug 24, 2016 at 05:53:00PM +0530, Vinay Simha wrote:
> if we do not set the polarity to 8mA, panel will have gibberish display.
> (information to set 8mA is available only in
> nexus7-msm-flo-3.4-lollipop-release_dsi kernel nx7 release)
> 
> i will add this
> reset-gpios = <&tlmm_pinmux 54 GPIO_ACTIVE_LOW>;

I don't think that will work with the current driver, because the GPIO
subsystem will automatically invert the value for you. Currently the
panel driver sets the GPIO value to 0 to assert the reset. With the
GPIO_ACTIVE_LOW flag you'd end up setting the actual level of the GPIO
to high, which is going to deassert. So I think if you make the above
change (which I think is the right thing to do), you'll also have to
update the driver to use high-active logic.

Thierry

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[RESEND] [PATCH v3 3/4] drm/dsi: Implement dcs set/get display brightness

[Vinay Simha BN]

Provide a small convenience wrapper that set/get the
display brightness value

Cc: John Stultz <john.stultz@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Archit Taneja <archit.taneja@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>

---
v1:
 *tested in nexus7 2nd gen.

v2:
 * implemented jani review comments
   -functions name mapped accordingly
   -bl value increased from 0xff to 0xffff
   -backlight interface will be handled in panel driver,
    so it is moved from the mipi_dsi helper function

v3:
 * emil review comments
   (err < 0) supposed to be (err <= 0)
---
 drivers/gpu/drm/drm_mipi_dsi.c | 49 ++++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_mipi_dsi.h     |  4 ++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index af0d471..43aa743 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -1041,6 +1041,55 @@ int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format)
 }
 EXPORT_SYMBOL(mipi_dsi_dcs_set_pixel_format);
 
+/**
+ * mipi_dsi_dcs_get_display_brightness() - gets the current brightness value
+ * of the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
+					u16 *brightness)
+{
+	ssize_t err;
+
+	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
+				brightness, sizeof(*brightness));
+	if (err <= 0) {
+		if (err == 0)
+			err = -ENODATA;
+
+		return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_get_display_brightness);
+
+/**
+ * mipi_dsi_dcs_set_display_brightness() - sets the brightness value of
+ * the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
+					u16 brightness)
+{
+	ssize_t err;
+	u8 bl_value[2] = { brightness & 0xff, brightness >> 8 };
+
+	err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
+				 bl_value, sizeof(bl_value));
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_set_display_brightness);
+
 static int mipi_dsi_drv_probe(struct device *dev)
 {
 	struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 47ac925..404c373 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -270,6 +270,10 @@ int mipi_dsi_dcs_set_tear_off(struct mipi_dsi_device *dsi);
 int mipi_dsi_dcs_set_tear_on(struct mipi_dsi_device *dsi,
 			     enum mipi_dsi_dcs_tear_mode mode);
 int mipi_dsi_dcs_set_pixel_format(struct mipi_dsi_device *dsi, u8 format);
+int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
+					u16 *brightness);
+int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
+					u16 brightness);
 
 /**
  * struct mipi_dsi_driver - DSI driver
-- 
2.1.2

Re: [RESEND] [PATCH v3 3/4] drm/dsi: Implement dcs set/get display brightness

[Thierry Reding]

[-- Attachment #1.1: Type: text/plain, Size: 1170 bytes --]

On Sun, Jul 31, 2016 at 08:45:22PM +0530, Vinay Simha BN wrote:
> Provide a small convenience wrapper that set/get the
> display brightness value
> 
> Cc: John Stultz <john.stultz@linaro.org>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: Archit Taneja <archit.taneja@gmail.com>
> Cc: Rob Clark <robdclark@gmail.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Thierry Reding <thierry.reding@gmail.com>
> Cc: Emil Velikov <emil.l.velikov@gmail.com>
> Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
> Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
> 
> ---
> v1:
>  *tested in nexus7 2nd gen.
> 
> v2:
>  * implemented jani review comments
>    -functions name mapped accordingly
>    -bl value increased from 0xff to 0xffff
>    -backlight interface will be handled in panel driver,
>     so it is moved from the mipi_dsi helper function
> 
> v3:
>  * emil review comments
>    (err < 0) supposed to be (err <= 0)
> ---
>  drivers/gpu/drm/drm_mipi_dsi.c | 49 ++++++++++++++++++++++++++++++++++++++++++
>  include/drm/drm_mipi_dsi.h     |  4 ++++
>  2 files changed, 53 insertions(+)

Applied, thanks.

Thierry

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[RESEND] [PATCH v9 4/4] drm/panel: Add JDI LT070ME05000 WUXGA DSI Panel

[Vinay Simha BN]

Add support for the JDI LT070ME05000 WUXGA DSI panel used in
Nexus 7 2013 devices.

Programming sequence for the panel is was originally found in the
android-msm-flo-3.4-lollipop-release branch from:
    https://android.googlesource.com/kernel/msm.git

And video mode setting is from dsi-panel-jdi-dualmipi1-video.dtsi
file in:
    git://codeaurora.org/kernel/msm-3.10.git  LNX.LA.3.6_rb1.27

Cc: Archit Taneja <archit.taneja@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: David Airlie <airlied@linux.ie>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
Tested-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>

---
v1:
 * sumit ported to drm/panel framework, john cherry-picked to mainline,
   folded down other fixes from Vinay and Archit, vinay removed interface
   setting cmd mode, video mode panel selected

v2:
 * incorporated code reviews from theiry, archit
   code style, alphabetical soring in Makefile, Kconfig, regulator_bulk,
   arrays of u8, generic helper function, documentation bindings,

v3:
 * dcs backlight support added
 * tested this panel driver in nexus7 2013 device

v4:
 * backlight interface added in the panel driver
 * incorporated width_mm and height_mm suggested by rob herring

v5:
 * theirry review comments incorporated
   panel model naming consistent, alphabetical soring in Kconfig
   Makefile, MAX_BRIGHTNESS dropped, regulator_names, parameterize
   panel width and height, descprition for control display, cabc
   and interface setting, temporary variable removed, consistent
   error reporting and commit message
 * removed tear on/off, scanline, since these are required only
   for command mode panels

v6:
 * emil review comments incorporated
   PANEL_NUM_REGULATORS dropped, return ret added at necessary
   places, if checks dropped for backlight and gpios

v7:
 * emil review comments incorporated
   added ARRAY_SIZE in struct, regulator_bulk_disable in poweroff,
   gpios checks dropped.
   some returns cannot be dropped, since drm panel framework return
   type required.

v8:
 * emil review commnets incorporated for jdi_panel_unprepare,
   dropped the returns (ref: panel-sharp-lq101r1sx01.c) and
   for jdi_panel_prepare(panel_on) it does not return prematurely
   and goes to poweroff if not success
 * few dev_err's for panel_init

v9:
 * function drm_panel_create_dsi_backlight made as static
---
 drivers/gpu/drm/panel/Kconfig                  |  11 +
 drivers/gpu/drm/panel/Makefile                 |   1 +
 drivers/gpu/drm/panel/panel-jdi-lt070me05000.c | 518 +++++++++++++++++++++++++
 3 files changed, 530 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-jdi-lt070me05000.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 1500ab9..62aba97 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -18,6 +18,17 @@ config DRM_PANEL_SIMPLE
 	  that it can be automatically turned off when the panel goes into a
 	  low power state.
 
+config DRM_PANEL_JDI_LT070ME05000
+	tristate "JDI LT070ME05000 WUXGA DSI panel"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	help
+	  Say Y here if you want to enable support for JDI DSI video mode
+	  panel as found in Google Nexus 7 (2013) devices.
+	  The panel has a 1200(RGB)×1920 (WUXGA) resolution and uses
+	  24 bit per pixel.
+
 config DRM_PANEL_SAMSUNG_LD9040
 	tristate "Samsung LD9040 RGB/SPI panel"
 	depends on OF && SPI
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index f277eed..a5c7ec0 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
+obj-$(CONFIG_DRM_PANEL_JDI_LT070ME05000) += panel-jdi-lt070me05000.o
 obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
 obj-$(CONFIG_DRM_PANEL_PANASONIC_VVX10F034N00) += panel-panasonic-vvx10f034n00.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_LD9040) += panel-samsung-ld9040.o
diff --git a/drivers/gpu/drm/panel/panel-jdi-lt070me05000.c b/drivers/gpu/drm/panel/panel-jdi-lt070me05000.c
new file mode 100644
index 0000000..517fa89
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-jdi-lt070me05000.c
@@ -0,0 +1,518 @@
+/*
+ * Copyright (C) 2016 InforceComputing
+ * Author: Vinay Simha BN <simhavcs@gmail.com>
+ *
+ * Copyright (C) 2016 Linaro Ltd
+ * Author: Sumit Semwal <sumit.semwal@linaro.org>
+ *
+ * From internet archives, the panel for Nexus 7 2nd Gen, 2013 model is a
+ * JDI model LT070ME05000, and its data sheet is at:
+ * http://panelone.net/en/7-0-inch/JDI_LT070ME05000_7.0_inch-datasheet
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/backlight.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+
+#include <drm/drmP.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_panel.h>
+
+#include <video/mipi_display.h>
+
+static const char * const regulator_names[] = {
+	"vddp",
+	"dcdc_en",
+	"vcc"
+};
+
+struct jdi_panel {
+	struct drm_panel base;
+	struct mipi_dsi_device *dsi;
+
+	struct regulator_bulk_data supplies[ARRAY_SIZE(regulator_names)];
+
+	struct gpio_desc *reset_gpio;
+	struct gpio_desc *enable_gpio;
+	struct backlight_device *backlight;
+
+	bool prepared;
+	bool enabled;
+
+	const struct drm_display_mode *mode;
+};
+
+static inline struct jdi_panel *to_jdi_panel(struct drm_panel *panel)
+{
+	return container_of(panel, struct jdi_panel, base);
+}
+
+static int jdi_panel_init(struct jdi_panel *jdi)
+{
+	struct mipi_dsi_device *dsi = jdi->dsi;
+	struct device *dev = &jdi->dsi->dev;
+	int ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_soft_reset(dsi);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(10000, 20000);
+
+	ret = mipi_dsi_dcs_set_pixel_format(dsi, MIPI_DCS_PIXEL_FMT_24BIT << 4);
+	if (ret < 0) {
+		dev_err(dev, "failed to set pixel format: %d\n", ret);
+		return ret;
+	}
+
+	ret = mipi_dsi_dcs_set_column_address(dsi, 0, jdi->mode->hdisplay - 1);
+	if (ret < 0) {
+		dev_err(dev, "failed to set column address: %d\n", ret);
+		return ret;
+	}
+
+	ret = mipi_dsi_dcs_set_page_address(dsi, 0, jdi->mode->vdisplay - 1);
+	if (ret < 0) {
+		dev_err(dev, "failed to set page address: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * BIT(5) BCTRL = 1 Backlight Control Block On, Brightness registers
+	 *                  are active
+	 * BIT(3) BL = 1    Backlight Control On
+	 * BIT(2) DD = 0    Display Dimming is Off
+	 */
+	ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_WRITE_CONTROL_DISPLAY,
+				 (u8[]){ 0x24 }, 1);
+	if (ret < 0) {
+		dev_err(dev, "failed to write control display: %d\n", ret);
+		return ret;
+	}
+
+	/* CABC off */
+	ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_WRITE_POWER_SAVE,
+				 (u8[]){ 0x00 }, 1);
+	if (ret < 0) {
+		dev_err(dev, "failed to set cabc off: %d\n", ret);
+		return ret;
+	}
+
+	ret = mipi_dsi_dcs_exit_sleep_mode(dsi);
+	if (ret < 0) {
+		dev_err(dev, "failed to set exit sleep mode: %d\n", ret);
+		return ret;
+	}
+
+	msleep(120);
+
+	ret = mipi_dsi_generic_write(dsi, (u8[]){0xB0, 0x00}, 2);
+	if (ret < 0) {
+		dev_err(dev, "failed to set mcap: %d\n", ret);
+		return ret;
+	}
+
+	mdelay(10);
+
+	/* Interface setting, video mode */
+	ret = mipi_dsi_generic_write(dsi, (u8[])
+				     {0xB3, 0x26, 0x08, 0x00, 0x20, 0x00}, 6);
+	if (ret < 0) {
+		dev_err(dev, "failed to set display interface setting: %d\n"
+			, ret);
+		return ret;
+	}
+
+	mdelay(20);
+
+	ret = mipi_dsi_generic_write(dsi, (u8[]){0xB0, 0x03}, 2);
+	if (ret < 0) {
+		dev_err(dev, "failed to set default values for mcap: %d\n"
+			, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int jdi_panel_on(struct jdi_panel *jdi)
+{
+	struct mipi_dsi_device *dsi = jdi->dsi;
+	struct device *dev = &jdi->dsi->dev;
+	int ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_set_display_on(dsi);
+	if (ret < 0)
+		dev_err(dev, "failed to set display on: %d\n", ret);
+
+	return ret;
+}
+
+static void jdi_panel_off(struct jdi_panel *jdi)
+{
+	struct mipi_dsi_device *dsi = jdi->dsi;
+	struct device *dev = &jdi->dsi->dev;
+	int ret;
+
+	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_set_display_off(dsi);
+	if (ret < 0)
+		dev_err(dev, "failed to set display off: %d\n", ret);
+
+	ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
+	if (ret < 0)
+		dev_err(dev, "failed to enter sleep mode: %d\n", ret);
+
+	msleep(100);
+}
+
+static int jdi_panel_disable(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_jdi_panel(panel);
+
+	if (!jdi->enabled)
+		return 0;
+
+	jdi->backlight->props.power = FB_BLANK_POWERDOWN;
+	backlight_update_status(jdi->backlight);
+
+	jdi->enabled = false;
+
+	return 0;
+}
+
+static int jdi_panel_unprepare(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_jdi_panel(panel);
+	struct device *dev = &jdi->dsi->dev;
+	int ret;
+
+	if (!jdi->prepared)
+		return 0;
+
+	jdi_panel_off(jdi);
+
+	ret = regulator_bulk_disable(ARRAY_SIZE(jdi->supplies), jdi->supplies);
+	if (ret < 0)
+		dev_err(dev, "regulator disable failed, %d\n", ret);
+
+	gpiod_set_value(jdi->enable_gpio, 0);
+
+	gpiod_set_value(jdi->reset_gpio, 0);
+
+	jdi->prepared = false;
+
+	return 0;
+}
+
+static int jdi_panel_prepare(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_jdi_panel(panel);
+	struct device *dev = &jdi->dsi->dev;
+	int ret;
+
+	if (jdi->prepared)
+		return 0;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(jdi->supplies), jdi->supplies);
+	if (ret < 0) {
+		dev_err(dev, "regulator enable failed, %d\n", ret);
+		return ret;
+	}
+
+	msleep(20);
+
+	gpiod_set_value(jdi->reset_gpio, 1);
+	usleep_range(10, 20);
+
+	gpiod_set_value(jdi->enable_gpio, 1);
+	usleep_range(10, 20);
+
+	ret = jdi_panel_init(jdi);
+	if (ret < 0) {
+		dev_err(dev, "failed to init panel: %d\n", ret);
+		goto poweroff;
+	}
+
+	ret = jdi_panel_on(jdi);
+	if (ret < 0) {
+		dev_err(dev, "failed to set panel on: %d\n", ret);
+		goto poweroff;
+	}
+
+	jdi->prepared = true;
+
+	return 0;
+
+poweroff:
+	ret = regulator_bulk_disable(ARRAY_SIZE(jdi->supplies), jdi->supplies);
+	if (ret < 0)
+		dev_err(dev, "regulator disable failed, %d\n", ret);
+
+	gpiod_set_value(jdi->enable_gpio, 0);
+
+	gpiod_set_value(jdi->reset_gpio, 0);
+
+	return ret;
+}
+
+static int jdi_panel_enable(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_jdi_panel(panel);
+
+	if (jdi->enabled)
+		return 0;
+
+	jdi->backlight->props.power = FB_BLANK_UNBLANK;
+	backlight_update_status(jdi->backlight);
+
+	jdi->enabled = true;
+
+	return 0;
+}
+
+static const struct drm_display_mode default_mode = {
+		.clock = 155493,
+		.hdisplay = 1200,
+		.hsync_start = 1200 + 48,
+		.hsync_end = 1200 + 48 + 32,
+		.htotal = 1200 + 48 + 32 + 60,
+		.vdisplay = 1920,
+		.vsync_start = 1920 + 3,
+		.vsync_end = 1920 + 3 + 5,
+		.vtotal = 1920 + 3 + 5 + 6,
+		.vrefresh = 60,
+		.flags = 0,
+};
+
+static int jdi_panel_get_modes(struct drm_panel *panel)
+{
+	struct drm_display_mode *mode;
+	struct jdi_panel *jdi = to_jdi_panel(panel);
+	struct device *dev = &jdi->dsi->dev;
+
+	mode = drm_mode_duplicate(panel->drm, &default_mode);
+	if (!mode) {
+		dev_err(dev, "failed to add mode %ux%ux@%u\n",
+			default_mode.hdisplay, default_mode.vdisplay,
+			default_mode.vrefresh);
+		return -ENOMEM;
+	}
+
+	drm_mode_set_name(mode);
+
+	drm_mode_probed_add(panel->connector, mode);
+
+	panel->connector->display_info.width_mm = 95;
+	panel->connector->display_info.height_mm = 151;
+
+	return 1;
+}
+
+static int dsi_dcs_bl_get_brightness(struct backlight_device *bl)
+{
+	struct mipi_dsi_device *dsi = bl_get_data(bl);
+	int ret;
+	u16 brightness = bl->props.brightness;
+
+	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_get_display_brightness(dsi, &brightness);
+	if (ret < 0)
+		return ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	return brightness & 0xff;
+}
+
+static int dsi_dcs_bl_update_status(struct backlight_device *bl)
+{
+	struct mipi_dsi_device *dsi = bl_get_data(bl);
+	int ret;
+
+	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_set_display_brightness(dsi, bl->props.brightness);
+	if (ret < 0)
+		return ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	return 0;
+}
+
+static const struct backlight_ops dsi_bl_ops = {
+	.update_status = dsi_dcs_bl_update_status,
+	.get_brightness = dsi_dcs_bl_get_brightness,
+};
+
+static struct backlight_device *
+drm_panel_create_dsi_backlight(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	struct backlight_properties props;
+
+	memset(&props, 0, sizeof(props));
+	props.type = BACKLIGHT_RAW;
+	props.brightness = 255;
+	props.max_brightness = 255;
+
+	return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
+					      &dsi_bl_ops, &props);
+}
+
+static const struct drm_panel_funcs jdi_panel_funcs = {
+	.disable = jdi_panel_disable,
+	.unprepare = jdi_panel_unprepare,
+	.prepare = jdi_panel_prepare,
+	.enable = jdi_panel_enable,
+	.get_modes = jdi_panel_get_modes,
+};
+
+static const struct of_device_id jdi_of_match[] = {
+	{ .compatible = "jdi,lt070me05000", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, jdi_of_match);
+
+static int jdi_panel_add(struct jdi_panel *jdi)
+{
+	struct device *dev = &jdi->dsi->dev;
+	int ret;
+	unsigned int i;
+
+	jdi->mode = &default_mode;
+
+	for (i = 0; i < ARRAY_SIZE(jdi->supplies); i++)
+		jdi->supplies[i].supply = regulator_names[i];
+
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(jdi->supplies),
+				      jdi->supplies);
+	if (ret < 0) {
+		dev_err(dev, "failed to init regulator, ret=%d\n", ret);
+		return ret;
+	}
+
+	jdi->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(jdi->reset_gpio)) {
+		ret = PTR_ERR(jdi->reset_gpio);
+		dev_err(dev, "cannot get reset-gpios %d\n", ret);
+		return ret;
+	}
+
+	jdi->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(jdi->enable_gpio)) {
+		ret = PTR_ERR(jdi->enable_gpio);
+		dev_err(dev, "cannot get enable-gpio %d\n", ret);
+		return ret;
+	}
+
+	jdi->backlight = drm_panel_create_dsi_backlight(jdi->dsi);
+	if (IS_ERR(jdi->backlight)) {
+		ret = PTR_ERR(jdi->backlight);
+		dev_err(dev, "failed to register backlight %d\n", ret);
+		return ret;
+	}
+
+	drm_panel_init(&jdi->base);
+	jdi->base.funcs = &jdi_panel_funcs;
+	jdi->base.dev = &jdi->dsi->dev;
+
+	ret = drm_panel_add(&jdi->base);
+
+	return ret;
+}
+
+static void jdi_panel_del(struct jdi_panel *jdi)
+{
+	if (jdi->base.dev)
+		drm_panel_remove(&jdi->base);
+}
+
+static int jdi_panel_probe(struct mipi_dsi_device *dsi)
+{
+	struct jdi_panel *jdi;
+	int ret;
+
+	dsi->lanes = 4;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->mode_flags =  MIPI_DSI_MODE_VIDEO_HSE | MIPI_DSI_MODE_VIDEO |
+			   MIPI_DSI_CLOCK_NON_CONTINUOUS;
+
+	jdi = devm_kzalloc(&dsi->dev, sizeof(*jdi), GFP_KERNEL);
+	if (!jdi)
+		return -ENOMEM;
+
+	mipi_dsi_set_drvdata(dsi, jdi);
+
+	jdi->dsi = dsi;
+
+	ret = jdi_panel_add(jdi);
+	if (ret < 0)
+		return ret;
+
+	return mipi_dsi_attach(dsi);
+}
+
+static int jdi_panel_remove(struct mipi_dsi_device *dsi)
+{
+	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
+	int ret;
+
+	ret = jdi_panel_disable(&jdi->base);
+	if (ret < 0)
+		dev_err(&dsi->dev, "failed to disable panel: %d\n", ret);
+
+	ret = mipi_dsi_detach(dsi);
+	if (ret < 0)
+		dev_err(&dsi->dev, "failed to detach from DSI host: %d\n",
+			ret);
+
+	drm_panel_detach(&jdi->base);
+	jdi_panel_del(jdi);
+
+	return 0;
+}
+
+static void jdi_panel_shutdown(struct mipi_dsi_device *dsi)
+{
+	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
+
+	jdi_panel_disable(&jdi->base);
+}
+
+static struct mipi_dsi_driver jdi_panel_driver = {
+	.driver = {
+		.name = "panel-jdi-lt070me05000",
+		.of_match_table = jdi_of_match,
+	},
+	.probe = jdi_panel_probe,
+	.remove = jdi_panel_remove,
+	.shutdown = jdi_panel_shutdown,
+};
+module_mipi_dsi_driver(jdi_panel_driver);
+
+MODULE_AUTHOR("Sumit Semwal <sumit.semwal@linaro.org>");
+MODULE_AUTHOR("Vinay Simha BN <simhavcs@gmail.com>");
+MODULE_DESCRIPTION("JDI LT070ME05000 WUXGA");
+MODULE_LICENSE("GPL v2");
-- 
2.1.2