Re: [V7, 1/2] media: dt-bindings: media: i2c: Document OV02A10 bindings

Sakari Ailus
2020-05-06T11:21:44Z

Hi Dongchun,

On Tue, May 05, 2020 at 10:17:18PM +0800, Dongchun Zhu wrote:
> Hi Sakari,
>
> Thanks for the review.
>
> On Tue, 2020-05-05 at 10:04 +0300, Sakari Ailus wrote:
> > Hi Dongchun,
> >
> > On Thu, Apr 30, 2020 at 04:09:23PM +0800, Dongchun Zhu wrote:
> > > Add DT bindings documentation for Omnivision OV02A10 image sensor.
> > >
> > > Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > > ---
> > > .../bindings/media/i2c/ovti,ov02a10.yaml | 148 +++++++++++++++++++++
> > > MAINTAINERS | 7 +
> > > 2 files changed, 155 insertions(+)
> > > create mode 100644 Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml b/Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > > new file mode 100644
> > > index 0000000..2be4bd2
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > > @@ -0,0 +1,148 @@
> > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > > +# Copyright (c) 2020 MediaTek Inc.
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/media/i2c/ovti,ov02a10.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Omnivision OV02A10 CMOS Sensor Device Tree Bindings
> > > +
> > > +maintainers:
> > > + - Dongchun Zhu <dongchun.zhu@mediatek.com>
> > > +
> > > +description: |-
> > > + The Omnivision OV02A10 is a low-cost, high performance, 1/5-inch, 2 megapixel
> > > + image sensor, which is the latest production derived from Omnivision's CMOS
> > > + image sensor technology. Ihis chip supports high frame rate speeds up to 30fps
> > > + @ 1600x1200 (UXGA) resolution transferred over a 1-lane MIPI interface. The
> > > + sensor output is available via CSI-2 serial data output.
> > > +
> > > +properties:
> > > + compatible:
> > > + const: ovti,ov02a10
> > > +
> > > + reg:
> > > + maxItems: 1
> > > +
> > > + clocks:
> > > + items:
> > > + - description: top mux camtg clock
> > > + - description: devider clock
> > > +
> > > + clock-names:
> > > + items:
> > > + - const: eclk
> > > + - const: freq_mux
> > > +
> > > + clock-frequency:
> > > + description:
> > > + Frequency of the eclk clock in Hertz.
> > > +
> > > + dovdd-supply:
> > > + description:
> > > + Definition of the regulator used as interface power supply.
> > > +
> > > + avdd-supply:
> > > + description:
> > > + Definition of the regulator used as analog power supply.
> > > +
> > > + dvdd-supply:
> > > + description:
> > > + Definition of the regulator used as digital power supply.
> > > +
> > > + powerdown-gpios:
> > > + description:
> > > + The phandle and specifier for the GPIO that controls sensor powerdown.
> > > +
> > > + reset-gpios:
> > > + description:
> > > + The phandle and specifier for the GPIO that controls sensor reset.
> > > +
> > > + rotation:
> > > + description:
> > > + Definition of the sensor's placement, valid values are 0 and 180.
> > > + allOf:
> > > + - $ref: "/schemas/types.yaml#/definitions/uint32"
> > > + - enum:
> > > + - 0 # Sensor Mounted Upright
> > > + - 180 # Sensor Mounted Upside Down
> > > +
> > > + ovti,mipi-tx-speed:
> > > + description:
> > > + Indication of MIPI transmission speed select.
> >
> > What exactly does this signify? And how do you come up with the number?
> >
>
> Apologies for not addressing this number clear.
>
> From the datasheet, P1:0xA1 register represents TX_SPEED_AREA_SEL with
> the default val: 0x03.
> The description of this RW register is as below:
> Bit[2:0]: MIPI transmission speed select.
>
> Thus the enum should be definited as [ 0, 1, 2, 3, 4, 5, 6, 7 ].
> This would be fixed in next release.
>
> In the meantime, as the default val of P1:0xA1 is 0x03, we hope to keep
> that value if there is no setting for this private property in DT.
> The caller in driver would be updated like this in next release.
> if (ov02a10->mipi_clock_tx_speed)
> ret = i2c_smbus_write_byte_data(...,...);

How did you pick the value in the example? And why do you believe it is
specific to a platform, and not e.g. a sensor mode?

>
> > > + allOf:
> > > + - $ref: "/schemas/types.yaml#/definitions/uint32"
> > > + - enum: [ 3, 4 ]
> > > +
> > > + # See ../video-interfaces.txt for details
> > > + port:
> > > + type: object
> > > + additionalProperties: false
> > > +
> > > + properties:
> > > + endpoint:
> > > + type: object
> > > + additionalProperties: false
> > > +
> > > + properties:
> > > + remote-endpoint: true
> > > + link-frequencies: true
> > > +
> > > + required:
> > > + - endpoint
> > > +
> > > +required:
> > > + - compatible
> > > + - reg
> > > + - clocks
> > > + - clock-names
> > > + - clock-frequency
> > > + - dovdd-supply
> > > + - avdd-supply
> > > + - dvdd-supply
> > > + - powerdown-gpios
> > > + - reset-gpios
> > > + - port
> > > +
> > > +additionalProperties: false
> > > +
> > > +examples:
> > > + - |
> > > + #include <dt-bindings/clock/mt8183-clk.h>
> > > + #include <dt-bindings/gpio/gpio.h>
> > > +
> > > + i2c {
> > > + clock-frequency = <400000>;
> > > + #address-cells = <1>;
> > > + #size-cells = <0>;
> > > +
> > > + ov02a10: camera-sensor@3d {
> > > + compatible = "ovti,ov02a10";
> > > + reg = <0x3d>;
> > > + pinctrl-names = "default";
> > > + pinctrl-0 = <&clk_24m_cam>;
> > > +
> > > + clocks = <&topckgen CLK_TOP_MUX_CAMTG>,
> > > + <&topckgen CLK_TOP_UNIVP_192M_D8>;
> > > + clock-names = "eclk", "freq_mux";
> > > + clock-frequency = <24000000>;
> > > +
> > > + rotation = <180>;
> > > + ovti,mipi-tx-speed = <3>;
> > > +
> > > + dovdd-supply = <&mt6358_vcamio_reg>;
> > > + avdd-supply = <&mt6358_vcama1_reg>;
> > > + dvdd-supply = <&mt6358_vcn18_reg>;
> > > + powerdown-gpios = <&pio 107 GPIO_ACTIVE_LOW>;
> > > + reset-gpios = <&pio 109 GPIO_ACTIVE_HIGH>;
> > > +
> > > + port {
> > > + wcam_out: endpoint {
> > > + remote-endpoint = <&mipi_in_wcam>;
> > > + link-frequencies = /bits/ 64 <390000000>;
> > > + };
> > > + };
> > > + };
> > > + };
> > > +
> > > +...
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index e64e5db..63a2335 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -12389,6 +12389,13 @@ M: Harald Welte <laforge@gnumonks.org>
> > > S: Maintained
> > > F: drivers/char/pcmcia/cm4040_cs.*
> > >
> > > +OMNIVISION OV02A10 SENSOR DRIVER
> > > +M: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > > +L: linux-media@vger.kernel.org
> > > +S: Maintained
> > > +T: git git://linuxtv.org/media_tree.git
> > > +F: Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > > +
> > > OMNIVISION OV13858 SENSOR DRIVER
> > > M: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > L: linux-media@vger.kernel.org
> >
>

--
Regards,

Sakari Ailus