[PATCH v13 0/2] media: i2c: Add support for OV02A10 sensor

[PATCH v13 0/2] media: i2c: Add support for OV02A10 sensor

[Dongchun Zhu]

Hello,

This series adds YAML DT binding and V4L2 sub-device driver for Omnivision's
OV02A10 2-megapixel 10-bit RAW CMOS 1/5" sensor, which has a single MIPI lane
interface and uses the I2C bus for control and the CSI-2 bus for data.

The driver is implemented with V4L2 framework.
 - Async registered as a V4L2 sub-device.
 - As the first component of camera system including Seninf, ISP pipeline.
 - A media entity that provides one source pad in common and two for dual-cam.
 - Used in camera features on CrOS application.

Also this driver supports following features:
 - manual exposure and analog gain control support
 - vertical blanking control support
 - test pattern support
 - media controller support
 - runtime PM support
 - support resolution: 1600x1200 at 30FPS
 
Previous versions of this patch-set can be found here:
 v12: https://lore.kernel.org/linux-media/20200702115223.21507-1-dongchun.zhu@mediatek.com/
 v11: https://lore.kernel.org/linux-media/20200630024942.20891-1-dongchun.zhu@mediatek.com/
 v10: https://lore.kernel.org/linux-media/20200615122937.18965-3-dongchun.zhu@mediatek.com/
 v09: https://lore.kernel.org/linux-media/20200523084103.31276-1-dongchun.zhu@mediatek.com/
 v08: https://lore.kernel.org/linux-media/20200509080627.23222-1-dongchun.zhu@mediatek.com/
 v07: https://lore.kernel.org/linux-media/20200430080924.1140-1-dongchun.zhu@mediatek.com/
 v06: https://lore.kernel.org/linux-media/20191211112849.16705-1-dongchun.zhu@mediatek.com/
 v05: https://lore.kernel.org/linux-media/20191104105713.24311-1-dongchun.zhu@mediatek.com/
 v04: https://lore.kernel.org/linux-media/20190907092728.23897-1-dongchun.zhu@mediatek.com/
 v03: https://lore.kernel.org/linux-media/20190819034331.13098-1-dongchun.zhu@mediatek.com/
 v02: https://lore.kernel.org/linux-media/20190704084651.3105-1-dongchun.zhu@mediatek.com/
 v01: https://lore.kernel.org/linux-media/20190523102204.24112-1-dongchun.zhu@mediatek.com/

Changes of v13 mainly address comments from Rob.
Compared to v12:
 - Add reviewed-by for sensor driver
 - Fix a build-warning and the warning when applying the patch with git am

Please review.
Thanks.

Dongchun Zhu (2):
  media: dt-bindings: media: i2c: Document OV02A10 bindings
  media: i2c: Add OV02A10 image sensor driver

 .../bindings/media/i2c/ovti,ov02a10.yaml           |  172 ++++
 MAINTAINERS                                        |    8 +
 drivers/media/i2c/Kconfig                          |   13 +
 drivers/media/i2c/Makefile                         |    1 +
 drivers/media/i2c/ov02a10.c                        | 1050 ++++++++++++++++++++
 5 files changed, 1244 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
 create mode 100644 drivers/media/i2c/ov02a10.c

-- 
2.9.2

[PATCH v13 1/2] media: dt-bindings: media: i2c: Document OV02A10 bindings

[Dongchun Zhu]

Add YAML device tree binding for OV02A10 CMOS image sensor,
and the relevant MAINTAINERS entries.

Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
---
 .../bindings/media/i2c/ovti,ov02a10.yaml           | 172 +++++++++++++++++++++
 MAINTAINERS                                        |   7 +
 2 files changed, 179 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..3a916cc
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
@@ -0,0 +1,172 @@
+# 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: divider 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 Digital I/O voltage supply.
+
+  avdd-supply:
+    description:
+      Definition of the regulator used as Analog voltage supply.
+
+  dvdd-supply:
+    description:
+      Definition of the regulator used as Digital core voltage supply.
+
+  powerdown-gpios:
+    description:
+      Must be the device tree identifier of the GPIO connected to the
+      PD_PAD pin. This pin is used to place the OV02A10 into standby mode
+      or shutdown mode. As the line needs to be high for the powerdown mode
+      to be active, it should be marked GPIO_ACTIVE_HIGH.
+    maxItems: 1
+
+  reset-gpios:
+    description:
+      Must be the device tree identifier of the GPIO connected to the
+      RST_PD pin. If specified, it will be asserted during driver probe.
+      As the line needs to be low for the reset to be active, it should be
+      marked GPIO_ACTIVE_LOW.
+    maxItems: 1
+
+  rotation:
+    description:
+      Definition of the sensor's placement.
+    allOf:
+      - $ref: "/schemas/types.yaml#/definitions/uint32"
+      - enum:
+          - 0    # Sensor Mounted Upright
+          - 180  # Sensor Mounted Upside Down
+        default: 0
+
+  ovti,mipi-tx-speed:
+    description:
+      Indication of MIPI transmission speed select, which is to control D-PHY
+      timing setting by adjusting MIPI clock voltage to improve the clock
+      driver capability.
+    allOf:
+      - $ref: "/schemas/types.yaml#/definitions/uint32"
+      - enum:
+          - 0    #  20MHz -  30MHz
+          - 1    #  30MHz -  50MHz
+          - 2    #  50MHz -  75MHz
+          - 3    #  75MHz - 100MHz
+          - 4    # 100MHz - 130MHz
+        default: 3
+
+  # See ../video-interfaces.txt for details
+  port:
+    type: object
+    additionalProperties: false
+    description:
+      Output port node, single endpoint describing the CSI-2 transmitter.
+
+    properties:
+      endpoint:
+        type: object
+        additionalProperties: false
+
+        properties:
+          link-frequencies: true
+          remote-endpoint: true
+
+        required:
+          - link-frequencies
+          - remote-endpoint
+
+    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 {
+        #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 = <4>;
+
+            dovdd-supply = <&mt6358_vcamio_reg>;
+            avdd-supply = <&mt6358_vcama1_reg>;
+            dvdd-supply = <&mt6358_vcn18_reg>;
+
+            powerdown-gpios = <&pio 107 GPIO_ACTIVE_HIGH>;
+            reset-gpios = <&pio 109 GPIO_ACTIVE_LOW>;
+
+            port {
+                wcam_out: endpoint {
+                    link-frequencies = /bits/ 64 <390000000>;
+                    remote-endpoint = <&mipi_in_wcam>;
+                };
+            };
+        };
+    };
+
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 68f21d4..378c961 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12560,6 +12560,13 @@ 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
-- 
2.9.2

[PATCH v13 2/2] media: i2c: Add OV02A10 image sensor driver

[Dongchun Zhu]

Add a V4L2 sub-device driver for OmniVision OV02A10 image sensor.

Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
---
 MAINTAINERS                 |    1 +
 drivers/media/i2c/Kconfig   |   13 +
 drivers/media/i2c/Makefile  |    1 +
 drivers/media/i2c/ov02a10.c | 1050 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 1065 insertions(+)
 create mode 100644 drivers/media/i2c/ov02a10.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 378c961..a6a2f8b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12566,6 +12566,7 @@ 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
+F:	drivers/media/i2c/ov02a10.c
 
 OMNIVISION OV13858 SENSOR DRIVER
 M:	Sakari Ailus <sakari.ailus@linux.intel.com>
diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index da11036..65519cf 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -812,6 +812,19 @@ config VIDEO_IMX355
 	  To compile this driver as a module, choose M here: the
 	  module will be called imx355.
 
+config VIDEO_OV02A10
+	tristate "OmniVision OV02A10 sensor support"
+	depends on I2C && VIDEO_V4L2
+	select MEDIA_CONTROLLER
+	select VIDEO_V4L2_SUBDEV_API
+	select V4L2_FWNODE
+	help
+	  This is a Video4Linux2 sensor driver for the OmniVision
+	  OV02A10 camera.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ov02a10.
+
 config VIDEO_OV2640
 	tristate "OmniVision OV2640 sensor support"
 	depends on VIDEO_V4L2 && I2C
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index 993acab..384e676 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -63,6 +63,7 @@ obj-$(CONFIG_VIDEO_VP27SMPX) += vp27smpx.o
 obj-$(CONFIG_VIDEO_SONY_BTF_MPX) += sony-btf-mpx.o
 obj-$(CONFIG_VIDEO_UPD64031A) += upd64031a.o
 obj-$(CONFIG_VIDEO_UPD64083) += upd64083.o
+obj-$(CONFIG_VIDEO_OV02A10) += ov02a10.o
 obj-$(CONFIG_VIDEO_OV2640) += ov2640.o
 obj-$(CONFIG_VIDEO_OV2680) += ov2680.o
 obj-$(CONFIG_VIDEO_OV2685) += ov2685.o
diff --git a/drivers/media/i2c/ov02a10.c b/drivers/media/i2c/ov02a10.c
new file mode 100644
index 0000000..5ffc97a
--- /dev/null
+++ b/drivers/media/i2c/ov02a10.c
@@ -0,0 +1,1050 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 MediaTek Inc.
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
+#include <media/media-entity.h>
+#include <media/v4l2-async.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-subdev.h>
+#include <media/v4l2-fwnode.h>
+
+#define CHIP_ID						0x2509
+#define OV02A10_REG_CHIP_ID_H				0x02
+#define OV02A10_REG_CHIP_ID_L				0x03
+
+/* Bit[1] vertical upside down */
+/* Bit[0] horizontal mirror */
+#define REG_MIRROR_FLIP_CONTROL				0x3f
+
+/* Orientation */
+#define REG_MIRROR_FLIP_ENABLE				0x03
+
+/* Bit[2:0] MIPI transmission speed select */
+#define TX_SPEED_AREA_SEL				0xa1
+#define OV02A10_MIPI_TX_SPEED_DEFAULT			0x03
+
+#define REG_PAGE_SWITCH					0xfd
+#define REG_GLOBAL_EFFECTIVE				0x01
+#define REG_ENABLE					BIT(0)
+
+#define REG_SC_CTRL_MODE				0xac
+#define SC_CTRL_MODE_STANDBY				0x00
+#define SC_CTRL_MODE_STREAMING				0x01
+
+#define OV02A10_EXP_SHIFT				8
+#define OV02A10_REG_EXPOSURE_H				0x03
+#define OV02A10_REG_EXPOSURE_L				0x04
+#define	OV02A10_EXPOSURE_MIN				4
+#define OV02A10_EXPOSURE_MAX_MARGIN			4
+#define	OV02A10_EXPOSURE_STEP				1
+
+#define OV02A10_VTS_SHIFT				8
+#define OV02A10_REG_VTS_H				0x05
+#define OV02A10_REG_VTS_L				0x06
+#define OV02A10_VTS_MAX					0x209f
+#define OV02A10_BASIC_LINE				1224
+
+#define OV02A10_REG_GAIN				0x24
+#define OV02A10_GAIN_MIN				0x10
+#define OV02A10_GAIN_MAX				0xf8
+#define OV02A10_GAIN_STEP				0x01
+#define OV02A10_GAIN_DEFAULT				0x40
+
+/* Test pattern control */
+#define OV02A10_REG_TEST_PATTERN			0xb6
+
+#define HZ_PER_MHZ					1000000L
+#define OV02A10_LINK_FREQ_390MHZ			(390 * HZ_PER_MHZ)
+#define OV02A10_ECLK_FREQ				(24 * HZ_PER_MHZ)
+#define OV02A10_DATA_LANES				1
+#define OV02A10_BITS_PER_SAMPLE				10
+
+static const char * const ov02a10_supply_names[] = {
+	"dovdd",	/* Digital I/O power */
+	"avdd",		/* Analog power */
+	"dvdd",		/* Digital core power */
+};
+
+struct ov02a10_reg {
+	u8 addr;
+	u8 val;
+};
+
+struct ov02a10_reg_list {
+	u32 num_of_regs;
+	const struct ov02a10_reg *regs;
+};
+
+struct ov02a10_mode {
+	u32 width;
+	u32 height;
+	u32 exp_def;
+	u32 hts_def;
+	u32 vts_def;
+	const struct ov02a10_reg_list reg_list;
+};
+
+struct ov02a10 {
+	u32 eclk_freq;
+	u32 mipi_clock_tx_speed;
+
+	struct clk *eclk;
+	struct gpio_desc *pd_gpio;
+	struct gpio_desc *rst_gpio;
+	struct regulator_bulk_data supplies[ARRAY_SIZE(ov02a10_supply_names)];
+
+	bool streaming;
+	bool upside_down;
+
+	/*
+	 * Serialize control access, get/set format, get selection
+	 * and start streaming.
+	 */
+	struct mutex mutex;
+	struct v4l2_subdev subdev;
+	struct media_pad pad;
+	struct v4l2_mbus_framefmt fmt;
+	struct v4l2_ctrl_handler ctrl_handler;
+	struct v4l2_ctrl *exposure;
+
+	const struct ov02a10_mode *cur_mode;
+};
+
+static inline struct ov02a10 *to_ov02a10(struct v4l2_subdev *sd)
+{
+	return container_of(sd, struct ov02a10, subdev);
+}
+
+/*
+ * eclk 24Mhz
+ * pclk 39Mhz
+ * linelength 934(0x3a6)
+ * framelength 1390(0x56E)
+ * grabwindow_width 1600
+ * grabwindow_height 1200
+ * max_framerate 30fps
+ * mipi_datarate per lane 780Mbps
+ */
+static const struct ov02a10_reg ov02a10_1600x1200_regs[] = {
+	{0xfd, 0x01},
+	{0xac, 0x00},
+	{0xfd, 0x00},
+	{0x2f, 0x29},
+	{0x34, 0x00},
+	{0x35, 0x21},
+	{0x30, 0x15},
+	{0x33, 0x01},
+	{0xfd, 0x01},
+	{0x44, 0x00},
+	{0x2a, 0x4c},
+	{0x2b, 0x1e},
+	{0x2c, 0x60},
+	{0x25, 0x11},
+	{0x03, 0x01},
+	{0x04, 0xae},
+	{0x09, 0x00},
+	{0x0a, 0x02},
+	{0x06, 0xa6},
+	{0x31, 0x00},
+	{0x24, 0x40},
+	{0x01, 0x01},
+	{0xfb, 0x73},
+	{0xfd, 0x01},
+	{0x16, 0x04},
+	{0x1c, 0x09},
+	{0x21, 0x42},
+	{0x12, 0x04},
+	{0x13, 0x10},
+	{0x11, 0x40},
+	{0x33, 0x81},
+	{0xd0, 0x00},
+	{0xd1, 0x01},
+	{0xd2, 0x00},
+	{0x50, 0x10},
+	{0x51, 0x23},
+	{0x52, 0x20},
+	{0x53, 0x10},
+	{0x54, 0x02},
+	{0x55, 0x20},
+	{0x56, 0x02},
+	{0x58, 0x48},
+	{0x5d, 0x15},
+	{0x5e, 0x05},
+	{0x66, 0x66},
+	{0x68, 0x68},
+	{0x6b, 0x00},
+	{0x6c, 0x00},
+	{0x6f, 0x40},
+	{0x70, 0x40},
+	{0x71, 0x0a},
+	{0x72, 0xf0},
+	{0x73, 0x10},
+	{0x75, 0x80},
+	{0x76, 0x10},
+	{0x84, 0x00},
+	{0x85, 0x10},
+	{0x86, 0x10},
+	{0x87, 0x00},
+	{0x8a, 0x22},
+	{0x8b, 0x22},
+	{0x19, 0xf1},
+	{0x29, 0x01},
+	{0xfd, 0x01},
+	{0x9d, 0x16},
+	{0xa0, 0x29},
+	{0xa1, 0x03},
+	{0xad, 0x62},
+	{0xae, 0x00},
+	{0xaf, 0x85},
+	{0xb1, 0x01},
+	{0x8e, 0x06},
+	{0x8f, 0x40},
+	{0x90, 0x04},
+	{0x91, 0xb0},
+	{0x45, 0x01},
+	{0x46, 0x00},
+	{0x47, 0x6c},
+	{0x48, 0x03},
+	{0x49, 0x8b},
+	{0x4a, 0x00},
+	{0x4b, 0x07},
+	{0x4c, 0x04},
+	{0x4d, 0xb7},
+	{0xf0, 0x40},
+	{0xf1, 0x40},
+	{0xf2, 0x40},
+	{0xf3, 0x40},
+	{0x3f, 0x00},
+	{0xfd, 0x01},
+	{0x05, 0x00},
+	{0x06, 0xa6},
+	{0xfd, 0x01},
+};
+
+static const char * const ov02a10_test_pattern_menu[] = {
+	"Disabled",
+	"Eight Vertical Colour Bars",
+};
+
+static const s64 link_freq_menu_items[] = {
+	OV02A10_LINK_FREQ_390MHZ,
+};
+
+static u64 to_pixel_rate(u32 f_index)
+{
+	u64 pixel_rate = link_freq_menu_items[f_index] * 2 * OV02A10_DATA_LANES;
+
+	do_div(pixel_rate, OV02A10_BITS_PER_SAMPLE);
+
+	return pixel_rate;
+}
+
+static const struct ov02a10_mode supported_modes[] = {
+	{
+		.width = 1600,
+		.height = 1200,
+		.exp_def = 0x01ae,
+		.hts_def = 0x03a6,
+		.vts_def = 0x056e,
+		.reg_list = {
+			.num_of_regs = ARRAY_SIZE(ov02a10_1600x1200_regs),
+			.regs = ov02a10_1600x1200_regs,
+		},
+	},
+};
+
+static int ov02a10_write_array(struct ov02a10 *ov02a10,
+			       const struct ov02a10_reg_list *r_list)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < r_list->num_of_regs; i++) {
+		ret = i2c_smbus_write_byte_data(client, r_list->regs[i].addr,
+						r_list->regs[i].val);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ov02a10_read_smbus(struct ov02a10 *ov02a10, unsigned char reg,
+			      unsigned char *val)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(client, reg);
+	if (ret < 0)
+		return ret;
+
+	*val = (unsigned char)ret;
+
+	return 0;
+}
+
+static void ov02a10_fill_fmt(const struct ov02a10_mode *mode,
+			     struct v4l2_mbus_framefmt *fmt)
+{
+	fmt->width = mode->width;
+	fmt->height = mode->height;
+	fmt->field = V4L2_FIELD_NONE;
+}
+
+static int ov02a10_set_fmt(struct v4l2_subdev *sd,
+			   struct v4l2_subdev_pad_config *cfg,
+			   struct v4l2_subdev_format *fmt)
+{
+	struct ov02a10 *ov02a10 = to_ov02a10(sd);
+	struct v4l2_mbus_framefmt *mbus_fmt = &fmt->format;
+	struct v4l2_mbus_framefmt *frame_fmt;
+	int ret = 0;
+
+	mutex_lock(&ov02a10->mutex);
+
+	if (ov02a10->streaming && fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
+		ret = -EBUSY;
+		goto error;
+	}
+
+	/* Only one sensor mode supported */
+	mbus_fmt->code = ov02a10->fmt.code;
+	ov02a10_fill_fmt(ov02a10->cur_mode, mbus_fmt);
+
+	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY)
+		frame_fmt = v4l2_subdev_get_try_format(sd, cfg, 0);
+	else
+		frame_fmt = &ov02a10->fmt;
+
+	*frame_fmt = *mbus_fmt;
+
+error:
+	mutex_unlock(&ov02a10->mutex);
+	return ret;
+}
+
+static int ov02a10_get_fmt(struct v4l2_subdev *sd,
+			   struct v4l2_subdev_pad_config *cfg,
+			   struct v4l2_subdev_format *fmt)
+{
+	struct ov02a10 *ov02a10 = to_ov02a10(sd);
+	struct v4l2_mbus_framefmt *mbus_fmt = &fmt->format;
+
+	mutex_lock(&ov02a10->mutex);
+
+	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
+		fmt->format = *v4l2_subdev_get_try_format(sd, cfg, fmt->pad);
+	} else {
+		fmt->format = ov02a10->fmt;
+		mbus_fmt->code = ov02a10->fmt.code;
+		ov02a10_fill_fmt(ov02a10->cur_mode, mbus_fmt);
+	}
+
+	mutex_unlock(&ov02a10->mutex);
+
+	return 0;
+}
+
+static int ov02a10_enum_mbus_code(struct v4l2_subdev *sd,
+				  struct v4l2_subdev_pad_config *cfg,
+				  struct v4l2_subdev_mbus_code_enum *code)
+{
+	struct ov02a10 *ov02a10 = to_ov02a10(sd);
+
+	if (code->index != 0)
+		return -EINVAL;
+
+	code->code = ov02a10->fmt.code;
+
+	return 0;
+}
+
+static int ov02a10_enum_frame_sizes(struct v4l2_subdev *sd,
+				    struct v4l2_subdev_pad_config *cfg,
+				    struct v4l2_subdev_frame_size_enum *fse)
+{
+	if (fse->index >= ARRAY_SIZE(supported_modes))
+		return -EINVAL;
+
+	fse->min_width  = supported_modes[fse->index].width;
+	fse->max_width  = supported_modes[fse->index].width;
+	fse->max_height = supported_modes[fse->index].height;
+	fse->min_height = supported_modes[fse->index].height;
+
+	return 0;
+}
+
+static int ov02a10_check_sensor_id(struct ov02a10 *ov02a10)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+	u16 id;
+	u8 chip_id_h;
+	u8 chip_id_l;
+	int ret;
+
+	/* Check sensor revision */
+	ret = ov02a10_read_smbus(ov02a10, OV02A10_REG_CHIP_ID_H, &chip_id_h);
+	if (ret)
+		return ret;
+
+	ret = ov02a10_read_smbus(ov02a10, OV02A10_REG_CHIP_ID_L, &chip_id_l);
+	if (ret)
+		return ret;
+
+	id = (chip_id_h << 8) | chip_id_l;
+	if (id != CHIP_ID) {
+		dev_err(&client->dev, "Unexpected sensor id(%04x)\n", id);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ov02a10_power_on(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct ov02a10 *ov02a10 = to_ov02a10(sd);
+	int ret;
+
+	gpiod_set_value_cansleep(ov02a10->rst_gpio, 1);
+	gpiod_set_value_cansleep(ov02a10->pd_gpio, 1);
+
+	ret = clk_prepare_enable(ov02a10->eclk);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable eclk\n");
+		return ret;
+	}
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(ov02a10_supply_names),
+				    ov02a10->supplies);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable regulators\n");
+		goto disable_clk;
+	}
+	usleep_range(5000, 6000);
+
+	gpiod_set_value_cansleep(ov02a10->pd_gpio, 0);
+	usleep_range(5000, 6000);
+
+	gpiod_set_value_cansleep(ov02a10->rst_gpio, 0);
+	usleep_range(5000, 6000);
+
+	ret = ov02a10_check_sensor_id(ov02a10);
+	if (ret)
+		goto disable_regulator;
+
+	return 0;
+
+disable_regulator:
+	regulator_bulk_disable(ARRAY_SIZE(ov02a10_supply_names),
+			       ov02a10->supplies);
+disable_clk:
+	clk_disable_unprepare(ov02a10->eclk);
+
+	return ret;
+}
+
+static int ov02a10_power_off(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct ov02a10 *ov02a10 = to_ov02a10(sd);
+
+	gpiod_set_value_cansleep(ov02a10->rst_gpio, 1);
+	clk_disable_unprepare(ov02a10->eclk);
+	gpiod_set_value_cansleep(ov02a10->pd_gpio, 1);
+	regulator_bulk_disable(ARRAY_SIZE(ov02a10_supply_names),
+			       ov02a10->supplies);
+
+	return 0;
+}
+
+static int __ov02a10_start_stream(struct ov02a10 *ov02a10)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+	const struct ov02a10_reg_list *reg_list;
+	int ret;
+
+	/* Apply default values of current mode */
+	reg_list = &ov02a10->cur_mode->reg_list;
+	ret = ov02a10_write_array(ov02a10, reg_list);
+	if (ret)
+		return ret;
+
+	/* Apply customized values from user */
+	ret = __v4l2_ctrl_handler_setup(ov02a10->subdev.ctrl_handler);
+	if (ret)
+		return ret;
+
+	/* Set orientation to 180 degree */
+	if (ov02a10->upside_down) {
+		ret = i2c_smbus_write_byte_data(client, REG_MIRROR_FLIP_CONTROL,
+						REG_MIRROR_FLIP_ENABLE);
+		if (ret) {
+			dev_err(&client->dev, "failed to set orientation\n");
+			return ret;
+		}
+		ret = i2c_smbus_write_byte_data(client, REG_GLOBAL_EFFECTIVE,
+						REG_ENABLE);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Set mipi TX speed according to DT property */
+	if (ov02a10->mipi_clock_tx_speed != OV02A10_MIPI_TX_SPEED_DEFAULT) {
+		ret = i2c_smbus_write_byte_data(client, TX_SPEED_AREA_SEL,
+						ov02a10->mipi_clock_tx_speed);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Set stream on register */
+	return i2c_smbus_write_byte_data(client, REG_SC_CTRL_MODE,
+					 SC_CTRL_MODE_STREAMING);
+}
+
+static int __ov02a10_stop_stream(struct ov02a10 *ov02a10)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+
+	return i2c_smbus_write_byte_data(client, REG_SC_CTRL_MODE,
+					 SC_CTRL_MODE_STANDBY);
+}
+
+static int ov02a10_entity_init_cfg(struct v4l2_subdev *sd,
+				   struct v4l2_subdev_pad_config *cfg)
+{
+	struct v4l2_subdev_format fmt = {
+		.which = V4L2_SUBDEV_FORMAT_TRY,
+		.format = {
+			.width = 1600,
+			.height = 1200,
+		}
+	};
+
+	ov02a10_set_fmt(sd, cfg, &fmt);
+
+	return 0;
+}
+
+static int ov02a10_s_stream(struct v4l2_subdev *sd, int on)
+{
+	struct ov02a10 *ov02a10 = to_ov02a10(sd);
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+	int ret;
+
+	mutex_lock(&ov02a10->mutex);
+
+	if (ov02a10->streaming == on)
+		goto unlock_and_return;
+
+	if (on) {
+		ret = pm_runtime_get_sync(&client->dev);
+		if (ret < 0) {
+			pm_runtime_put_noidle(&client->dev);
+			goto unlock_and_return;
+		}
+
+		ret = __ov02a10_start_stream(ov02a10);
+		if (ret) {
+			__ov02a10_stop_stream(ov02a10);
+			ov02a10->streaming = !on;
+			goto err_rpm_put;
+		}
+	} else {
+		__ov02a10_stop_stream(ov02a10);
+		pm_runtime_put(&client->dev);
+	}
+
+	ov02a10->streaming = on;
+	mutex_unlock(&ov02a10->mutex);
+
+	return 0;
+
+err_rpm_put:
+	pm_runtime_put(&client->dev);
+unlock_and_return:
+	mutex_unlock(&ov02a10->mutex);
+
+	return ret;
+}
+
+static const struct dev_pm_ops ov02a10_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(ov02a10_power_off, ov02a10_power_on, NULL)
+};
+
+/*
+ * ov02a10_set_exposure - Function called when setting exposure time
+ * @priv: Pointer to device structure
+ * @val: Variable for exposure time, in the unit of micro-second
+ *
+ * Set exposure time based on input value.
+ *
+ * Return: 0 on success
+ */
+static int ov02a10_set_exposure(struct ov02a10 *ov02a10, int val)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client, REG_PAGE_SWITCH, REG_ENABLE);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_EXPOSURE_H,
+					val >> OV02A10_EXP_SHIFT);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_EXPOSURE_L, val);
+	if (ret < 0)
+		return ret;
+
+	return i2c_smbus_write_byte_data(client, REG_GLOBAL_EFFECTIVE,
+					 REG_ENABLE);
+}
+
+static int ov02a10_set_gain(struct ov02a10 *ov02a10, int val)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client, REG_PAGE_SWITCH, REG_ENABLE);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_GAIN, val);
+	if (ret < 0)
+		return ret;
+
+	return i2c_smbus_write_byte_data(client, REG_GLOBAL_EFFECTIVE,
+					 REG_ENABLE);
+}
+
+static int ov02a10_set_vblank(struct ov02a10 *ov02a10, int val)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+	u32 vts = val + ov02a10->cur_mode->height - OV02A10_BASIC_LINE;
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client, REG_PAGE_SWITCH, REG_ENABLE);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_VTS_H,
+					vts >> OV02A10_VTS_SHIFT);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_VTS_L, vts);
+	if (ret < 0)
+		return ret;
+
+	return i2c_smbus_write_byte_data(client, REG_GLOBAL_EFFECTIVE,
+					 REG_ENABLE);
+}
+
+static int ov02a10_set_test_pattern(struct ov02a10 *ov02a10, int pattern)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client, REG_PAGE_SWITCH, REG_ENABLE);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(client, OV02A10_REG_TEST_PATTERN,
+					pattern);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(client, REG_GLOBAL_EFFECTIVE,
+					REG_ENABLE);
+	if (ret < 0)
+		return ret;
+
+	return i2c_smbus_write_byte_data(client, REG_SC_CTRL_MODE,
+					 SC_CTRL_MODE_STREAMING);
+}
+
+static int ov02a10_set_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct ov02a10 *ov02a10 = container_of(ctrl->handler,
+					       struct ov02a10, ctrl_handler);
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+	s64 max_expo;
+	int ret;
+
+	/* Propagate change of current control to all related controls */
+	if (ctrl->id == V4L2_CID_VBLANK) {
+		/* Update max exposure while meeting expected vblanking */
+		max_expo = ov02a10->cur_mode->height + ctrl->val -
+			   OV02A10_EXPOSURE_MAX_MARGIN;
+		__v4l2_ctrl_modify_range(ov02a10->exposure,
+					 ov02a10->exposure->minimum, max_expo,
+					 ov02a10->exposure->step,
+					 ov02a10->exposure->default_value);
+	}
+
+	/* V4L2 controls values will be applied only when power is already up */
+	if (!pm_runtime_get_if_in_use(&client->dev))
+		return 0;
+
+	switch (ctrl->id) {
+	case V4L2_CID_EXPOSURE:
+		ret = ov02a10_set_exposure(ov02a10, ctrl->val);
+		break;
+	case V4L2_CID_ANALOGUE_GAIN:
+		ret = ov02a10_set_gain(ov02a10, ctrl->val);
+		break;
+	case V4L2_CID_VBLANK:
+		ret = ov02a10_set_vblank(ov02a10, ctrl->val);
+		break;
+	case V4L2_CID_TEST_PATTERN:
+		ret = ov02a10_set_test_pattern(ov02a10, ctrl->val);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	};
+
+	pm_runtime_put(&client->dev);
+
+	return ret;
+}
+
+static const struct v4l2_subdev_video_ops ov02a10_video_ops = {
+	.s_stream = ov02a10_s_stream,
+};
+
+static const struct v4l2_subdev_pad_ops ov02a10_pad_ops = {
+	.init_cfg = ov02a10_entity_init_cfg,
+	.enum_mbus_code = ov02a10_enum_mbus_code,
+	.enum_frame_size = ov02a10_enum_frame_sizes,
+	.get_fmt = ov02a10_get_fmt,
+	.set_fmt = ov02a10_set_fmt,
+};
+
+static const struct v4l2_subdev_ops ov02a10_subdev_ops = {
+	.video	= &ov02a10_video_ops,
+	.pad	= &ov02a10_pad_ops,
+};
+
+static const struct media_entity_operations ov02a10_subdev_entity_ops = {
+	.link_validate = v4l2_subdev_link_validate,
+};
+
+static const struct v4l2_ctrl_ops ov02a10_ctrl_ops = {
+	.s_ctrl = ov02a10_set_ctrl,
+};
+
+static int ov02a10_initialize_controls(struct ov02a10 *ov02a10)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
+	const struct ov02a10_mode *mode;
+	struct v4l2_ctrl_handler *handler;
+	struct v4l2_ctrl *ctrl;
+	s64 exposure_max;
+	s64 vblank_def;
+	s64 pixel_rate;
+	s64 h_blank;
+	int ret;
+
+	handler = &ov02a10->ctrl_handler;
+	mode = ov02a10->cur_mode;
+	ret = v4l2_ctrl_handler_init(handler, 7);
+	if (ret)
+		return ret;
+
+	handler->lock = &ov02a10->mutex;
+
+	ctrl = v4l2_ctrl_new_int_menu(handler, NULL, V4L2_CID_LINK_FREQ, 0, 0,
+				      link_freq_menu_items);
+	if (ctrl)
+		ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
+
+	pixel_rate = to_pixel_rate(0);
+	v4l2_ctrl_new_std(handler, NULL, V4L2_CID_PIXEL_RATE, 0, pixel_rate, 1,
+			  pixel_rate);
+
+	h_blank = mode->hts_def - mode->width;
+	v4l2_ctrl_new_std(handler, NULL, V4L2_CID_HBLANK, h_blank, h_blank, 1,
+			  h_blank);
+
+	vblank_def = mode->vts_def - mode->height;
+	v4l2_ctrl_new_std(handler, &ov02a10_ctrl_ops, V4L2_CID_VBLANK,
+			  vblank_def, OV02A10_VTS_MAX - mode->height, 1,
+			  vblank_def);
+
+	exposure_max = mode->vts_def - 4;
+	ov02a10->exposure = v4l2_ctrl_new_std(handler, &ov02a10_ctrl_ops,
+					      V4L2_CID_EXPOSURE,
+					      OV02A10_EXPOSURE_MIN,
+					      exposure_max,
+					      OV02A10_EXPOSURE_STEP,
+					      mode->exp_def);
+
+	v4l2_ctrl_new_std(handler, &ov02a10_ctrl_ops,
+			  V4L2_CID_ANALOGUE_GAIN, OV02A10_GAIN_MIN,
+			  OV02A10_GAIN_MAX, OV02A10_GAIN_STEP,
+			  OV02A10_GAIN_DEFAULT);
+
+	v4l2_ctrl_new_std_menu_items(handler, &ov02a10_ctrl_ops,
+				     V4L2_CID_TEST_PATTERN,
+				     ARRAY_SIZE(ov02a10_test_pattern_menu) - 1,
+				     0, 0, ov02a10_test_pattern_menu);
+
+	if (handler->error) {
+		ret = handler->error;
+		dev_err(&client->dev, "failed to init controls(%d)\n", ret);
+		goto err_free_handler;
+	}
+
+	ov02a10->subdev.ctrl_handler = handler;
+
+	return 0;
+
+err_free_handler:
+	v4l2_ctrl_handler_free(handler);
+
+	return ret;
+}
+
+static int ov02a10_check_hwcfg(struct device *dev, struct ov02a10 *ov02a10)
+{
+	struct fwnode_handle *ep;
+	struct fwnode_handle *fwnode = dev_fwnode(dev);
+	struct v4l2_fwnode_endpoint bus_cfg = {
+		.bus_type = V4L2_MBUS_CSI2_DPHY,
+	};
+	unsigned int i, j;
+	int ret;
+
+	if (!fwnode)
+		return -EINVAL;
+
+	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
+	if (!ep)
+		return -ENXIO;
+
+	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
+	fwnode_handle_put(ep);
+	if (ret)
+		return ret;
+
+	if (!bus_cfg.nr_of_link_frequencies) {
+		dev_err(dev, "no link frequencies defined");
+		ret = -EINVAL;
+		goto check_hwcfg_error;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(link_freq_menu_items); i++) {
+		for (j = 0; j < bus_cfg.nr_of_link_frequencies; j++) {
+			if (link_freq_menu_items[i] ==
+				bus_cfg.link_frequencies[j])
+				break;
+		}
+
+		if (j == bus_cfg.nr_of_link_frequencies) {
+			dev_err(dev, "no link frequency %lld supported",
+				link_freq_menu_items[i]);
+			ret = -EINVAL;
+			goto check_hwcfg_error;
+		}
+	}
+
+check_hwcfg_error:
+	v4l2_fwnode_endpoint_free(&bus_cfg);
+
+	return ret;
+}
+
+static int ov02a10_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct ov02a10 *ov02a10;
+	unsigned int rotation;
+	unsigned int clock_lane_tx_speed;
+	unsigned int i;
+	int ret;
+
+	ov02a10 = devm_kzalloc(dev, sizeof(*ov02a10), GFP_KERNEL);
+	if (!ov02a10)
+		return -ENOMEM;
+
+	ret = ov02a10_check_hwcfg(dev, ov02a10);
+	if (ret) {
+		dev_err(dev, "failed to check HW configuration: %d", ret);
+		return ret;
+	}
+
+	v4l2_i2c_subdev_init(&ov02a10->subdev, client, &ov02a10_subdev_ops);
+	ov02a10->mipi_clock_tx_speed = OV02A10_MIPI_TX_SPEED_DEFAULT;
+	ov02a10->fmt.code = MEDIA_BUS_FMT_SBGGR10_1X10;
+
+	/* Optional indication of physical rotation of sensor */
+	ret = fwnode_property_read_u32(dev_fwnode(dev), "rotation", &rotation);
+	if (!ret && rotation == 180) {
+		ov02a10->upside_down = true;
+		ov02a10->fmt.code = MEDIA_BUS_FMT_SRGGB10_1X10;
+	}
+
+	/* Optional indication of mipi TX speed */
+	ret = fwnode_property_read_u32(dev_fwnode(dev), "ovti,mipi-tx-speed",
+				       &clock_lane_tx_speed);
+
+	if (!ret)
+		ov02a10->mipi_clock_tx_speed = clock_lane_tx_speed;
+
+	/* Get system clock (eclk) */
+	ov02a10->eclk = devm_clk_get(dev, "eclk");
+	if (IS_ERR(ov02a10->eclk)) {
+		ret = PTR_ERR(ov02a10->eclk);
+		dev_err(dev, "failed to get eclk %d\n", ret);
+		return ret;
+	}
+
+	ret = fwnode_property_read_u32(dev_fwnode(dev), "clock-frequency",
+				       &ov02a10->eclk_freq);
+	if (ret) {
+		dev_err(dev, "failed to get eclk frequency\n");
+		return ret;
+	}
+
+	ret = clk_set_rate(ov02a10->eclk, ov02a10->eclk_freq);
+	if (ret) {
+		dev_err(dev, "failed to set eclk frequency (24MHz)\n");
+		return ret;
+	}
+
+	if (clk_get_rate(ov02a10->eclk) != OV02A10_ECLK_FREQ) {
+		dev_warn(dev, "eclk mismatched, mode is based on 24MHz\n");
+		return -EINVAL;
+	}
+
+	ov02a10->pd_gpio = devm_gpiod_get(dev, "powerdown", GPIOD_OUT_HIGH);
+	if (IS_ERR(ov02a10->pd_gpio)) {
+		ret = PTR_ERR(ov02a10->pd_gpio);
+		dev_err(dev, "failed to get powerdown-gpios %d\n", ret);
+		return ret;
+	}
+
+	ov02a10->rst_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(ov02a10->rst_gpio)) {
+		ret = PTR_ERR(ov02a10->rst_gpio);
+		dev_err(dev, "failed to get reset-gpios %d\n", ret);
+		return ret;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(ov02a10_supply_names); i++)
+		ov02a10->supplies[i].supply = ov02a10_supply_names[i];
+
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ov02a10_supply_names),
+				      ov02a10->supplies);
+	if (ret) {
+		dev_err(dev, "failed to get regulators\n");
+		return ret;
+	}
+
+	mutex_init(&ov02a10->mutex);
+	ov02a10->cur_mode = &supported_modes[0];
+
+	ret = ov02a10_initialize_controls(ov02a10);
+	if (ret) {
+		dev_err(dev, "failed to initialize controls\n");
+		goto err_destroy_mutex;
+	}
+
+	ov02a10->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	ov02a10->subdev.entity.ops = &ov02a10_subdev_entity_ops;
+	ov02a10->subdev.entity.function = MEDIA_ENT_F_CAM_SENSOR;
+	ov02a10->pad.flags = MEDIA_PAD_FL_SOURCE;
+
+	ret = media_entity_pads_init(&ov02a10->subdev.entity, 1, &ov02a10->pad);
+	if (ret < 0) {
+		dev_err(dev, "failed to init entity pads: %d", ret);
+		goto err_free_handler;
+	}
+
+	pm_runtime_enable(dev);
+	if (!pm_runtime_enabled(dev)) {
+		ret = ov02a10_power_on(dev);
+		if (ret < 0) {
+			dev_err(dev, "failed to power on: %d\n", ret);
+			goto err_clean_entity;
+		}
+	}
+
+	ret = v4l2_async_register_subdev(&ov02a10->subdev);
+	if (ret) {
+		dev_err(dev, "failed to register V4L2 subdev: %d", ret);
+		goto err_power_off;
+	}
+
+	return 0;
+
+err_power_off:
+	if (pm_runtime_enabled(dev))
+		pm_runtime_disable(dev);
+	else
+		ov02a10_power_off(dev);
+err_clean_entity:
+	media_entity_cleanup(&ov02a10->subdev.entity);
+err_free_handler:
+	v4l2_ctrl_handler_free(ov02a10->subdev.ctrl_handler);
+err_destroy_mutex:
+	mutex_destroy(&ov02a10->mutex);
+
+	return ret;
+}
+
+static int ov02a10_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct ov02a10 *ov02a10 = to_ov02a10(sd);
+
+	v4l2_async_unregister_subdev(sd);
+	media_entity_cleanup(&sd->entity);
+	v4l2_ctrl_handler_free(sd->ctrl_handler);
+	pm_runtime_disable(&client->dev);
+	if (!pm_runtime_status_suspended(&client->dev))
+		ov02a10_power_off(&client->dev);
+	pm_runtime_set_suspended(&client->dev);
+	mutex_destroy(&ov02a10->mutex);
+
+	return 0;
+}
+
+static const struct of_device_id ov02a10_of_match[] = {
+	{ .compatible = "ovti,ov02a10" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, ov02a10_of_match);
+
+static struct i2c_driver ov02a10_i2c_driver = {
+	.driver = {
+		.name = "ov02a10",
+		.pm = &ov02a10_pm_ops,
+		.of_match_table = ov02a10_of_match,
+	},
+	.probe_new	= &ov02a10_probe,
+	.remove		= &ov02a10_remove,
+};
+
+module_i2c_driver(ov02a10_i2c_driver);
+
+MODULE_AUTHOR("Dongchun Zhu <dongchun.zhu@mediatek.com>");
+MODULE_DESCRIPTION("OmniVision OV02A10 sensor driver");
+MODULE_LICENSE("GPL v2");
-- 
2.9.2

Re: [PATCH v13 1/2] media: dt-bindings: media: i2c: Document OV02A10 bindings

[Tomasz Figa]

Hi Dongchun,

On Fri, Jul 10, 2020 at 12:19 PM Dongchun Zhu <dongchun.zhu@mediatek.com> wrote:
>
> Add YAML device tree binding for OV02A10 CMOS image sensor,
> and the relevant MAINTAINERS entries.
>
> Reviewed-by: Tomasz Figa <tfiga@chromium.org>
> Reviewed-by: Rob Herring <robh@kernel.org>
> Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> ---
>  .../bindings/media/i2c/ovti,ov02a10.yaml           | 172 +++++++++++++++++++++
>  MAINTAINERS                                        |   7 +
>  2 files changed, 179 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..3a916cc
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> @@ -0,0 +1,172 @@
> +# 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: divider clock
> +
> +  clock-names:
> +    items:
> +      - const: eclk
> +      - const: freq_mux

Why do we have two clocks here? Looking at the example suggests that
they may be the clocks of the SoC that the integration was done with.
However, the binding must only define the aspects of the particular
device, i.e. this sensor.

I suppose we should only have "eclk" here and it should be described
as "external clock for the sensor".

> +
> +  clock-frequency:
> +    description:
> +      Frequency of the eclk clock in Hertz.

nit: maybe Hz?

> +
> +  dovdd-supply:
> +    description:
> +      Definition of the regulator used as Digital I/O voltage supply.
> +
> +  avdd-supply:
> +    description:
> +      Definition of the regulator used as Analog voltage supply.
> +
> +  dvdd-supply:
> +    description:
> +      Definition of the regulator used as Digital core voltage supply.
> +
> +  powerdown-gpios:
> +    description:
> +      Must be the device tree identifier of the GPIO connected to the
> +      PD_PAD pin. This pin is used to place the OV02A10 into standby mode
> +      or shutdown mode. As the line needs to be high for the powerdown mode
> +      to be active, it should be marked GPIO_ACTIVE_HIGH.
> +    maxItems: 1
> +
> +  reset-gpios:
> +    description:
> +      Must be the device tree identifier of the GPIO connected to the
> +      RST_PD pin. If specified, it will be asserted during driver probe.
> +      As the line needs to be low for the reset to be active, it should be
> +      marked GPIO_ACTIVE_LOW.
> +    maxItems: 1
> +
> +  rotation:
> +    description:
> +      Definition of the sensor's placement.
> +    allOf:
> +      - $ref: "/schemas/types.yaml#/definitions/uint32"
> +      - enum:
> +          - 0    # Sensor Mounted Upright
> +          - 180  # Sensor Mounted Upside Down
> +        default: 0
> +
> +  ovti,mipi-tx-speed:
> +    description:
> +      Indication of MIPI transmission speed select, which is to control D-PHY
> +      timing setting by adjusting MIPI clock voltage to improve the clock
> +      driver capability.

The description says that the value adjusts "MIPI clock voltage".
Should the property be renamed to "ovti,mipi-clock-voltage"?

> +    allOf:
> +      - $ref: "/schemas/types.yaml#/definitions/uint32"
> +      - enum:
> +          - 0    #  20MHz -  30MHz
> +          - 1    #  30MHz -  50MHz
> +          - 2    #  50MHz -  75MHz
> +          - 3    #  75MHz - 100MHz
> +          - 4    # 100MHz - 130MHz
> +        default: 3
> +

I've discussed this on IRC with Sakari. It sounds like this works as
is for us because the driver currently only supports 1 mode, always
running the link at 390 MHz. This won't scale if one intends to add
more modes, because DT can't be expected to be updated when the driver
changes. The two are expected to be separate and backwards compatible.

I think we could model this in DT as an array of <link speed, clock
voltage> pairs. Similarly to the OPP bindings [1]. An example to have
all link speeds up to 390 MHz use the value 4:

ovti,mipi-clock-voltages = <
              /* KHz         clock voltage unit */
                 390000    4
>;

if one wants to select different voltage for different link, they
could do so as well. With the example below, the driver should
configure "3" for link frequencies <= 150 MHz and "4" for > 150 MHz <=
390 MHz. Link frequencies > 390 MHz should be disallowed.

ovti,mipi-clock-voltages = <
              /* KHz         clock voltage unit */
                 150000    3
                 390000    4
>;

What do you think?

[1] https://elixir.bootlin.com/linux/v5.9-rc3/source/Documentation/devicetree/bindings/opp/opp.txt

Best regards,
Tomasz

Re: [PATCH v13 1/2] media: dt-bindings: media: i2c: Document OV02A10 bindings

[Sakari Ailus]

Hi Tomasz,

Thanks for dressing this into words.

On Mon, Aug 31, 2020 at 01:44:27PM +0200, Tomasz Figa wrote:
> Hi Dongchun,
> 
> On Fri, Jul 10, 2020 at 12:19 PM Dongchun Zhu <dongchun.zhu@mediatek.com> wrote:
> >
> > Add YAML device tree binding for OV02A10 CMOS image sensor,
> > and the relevant MAINTAINERS entries.
> >
> > Reviewed-by: Tomasz Figa <tfiga@chromium.org>
> > Reviewed-by: Rob Herring <robh@kernel.org>
> > Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > ---
> >  .../bindings/media/i2c/ovti,ov02a10.yaml           | 172 +++++++++++++++++++++
> >  MAINTAINERS                                        |   7 +
> >  2 files changed, 179 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..3a916cc
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > @@ -0,0 +1,172 @@
> > +# 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: divider clock
> > +
> > +  clock-names:
> > +    items:
> > +      - const: eclk
> > +      - const: freq_mux
> 
> Why do we have two clocks here? Looking at the example suggests that
> they may be the clocks of the SoC that the integration was done with.
> However, the binding must only define the aspects of the particular
> device, i.e. this sensor.
> 
> I suppose we should only have "eclk" here and it should be described
> as "external clock for the sensor".
> 
> > +
> > +  clock-frequency:
> > +    description:
> > +      Frequency of the eclk clock in Hertz.
> 
> nit: maybe Hz?
> 
> > +
> > +  dovdd-supply:
> > +    description:
> > +      Definition of the regulator used as Digital I/O voltage supply.
> > +
> > +  avdd-supply:
> > +    description:
> > +      Definition of the regulator used as Analog voltage supply.
> > +
> > +  dvdd-supply:
> > +    description:
> > +      Definition of the regulator used as Digital core voltage supply.
> > +
> > +  powerdown-gpios:
> > +    description:
> > +      Must be the device tree identifier of the GPIO connected to the
> > +      PD_PAD pin. This pin is used to place the OV02A10 into standby mode
> > +      or shutdown mode. As the line needs to be high for the powerdown mode
> > +      to be active, it should be marked GPIO_ACTIVE_HIGH.
> > +    maxItems: 1
> > +
> > +  reset-gpios:
> > +    description:
> > +      Must be the device tree identifier of the GPIO connected to the
> > +      RST_PD pin. If specified, it will be asserted during driver probe.
> > +      As the line needs to be low for the reset to be active, it should be
> > +      marked GPIO_ACTIVE_LOW.
> > +    maxItems: 1
> > +
> > +  rotation:
> > +    description:
> > +      Definition of the sensor's placement.
> > +    allOf:
> > +      - $ref: "/schemas/types.yaml#/definitions/uint32"
> > +      - enum:
> > +          - 0    # Sensor Mounted Upright
> > +          - 180  # Sensor Mounted Upside Down
> > +        default: 0
> > +
> > +  ovti,mipi-tx-speed:
> > +    description:
> > +      Indication of MIPI transmission speed select, which is to control D-PHY
> > +      timing setting by adjusting MIPI clock voltage to improve the clock
> > +      driver capability.
> 
> The description says that the value adjusts "MIPI clock voltage".
> Should the property be renamed to "ovti,mipi-clock-voltage"?
> 
> > +    allOf:
> > +      - $ref: "/schemas/types.yaml#/definitions/uint32"
> > +      - enum:
> > +          - 0    #  20MHz -  30MHz
> > +          - 1    #  30MHz -  50MHz
> > +          - 2    #  50MHz -  75MHz
> > +          - 3    #  75MHz - 100MHz
> > +          - 4    # 100MHz - 130MHz
> > +        default: 3
> > +
> 
> I've discussed this on IRC with Sakari. It sounds like this works as
> is for us because the driver currently only supports 1 mode, always
> running the link at 390 MHz. This won't scale if one intends to add
> more modes, because DT can't be expected to be updated when the driver
> changes. The two are expected to be separate and backwards compatible.
> 
> I think we could model this in DT as an array of <link speed, clock
> voltage> pairs. Similarly to the OPP bindings [1]. An example to have
> all link speeds up to 390 MHz use the value 4:
> 
> ovti,mipi-clock-voltages = <
>               /* KHz         clock voltage unit */
>                  390000    4
> >;
> 
> if one wants to select different voltage for different link, they
> could do so as well. With the example below, the driver should
> configure "3" for link frequencies <= 150 MHz and "4" for > 150 MHz <=
> 390 MHz. Link frequencies > 390 MHz should be disallowed.
> 
> ovti,mipi-clock-voltages = <
>               /* KHz         clock voltage unit */
>                  150000    3
>                  390000    4
> >;
> 
> What do you think?

One more note on my proposal: use the index of the link frequency to access
the ovti,mipi-clock-voltages array. That should be more simple for the
driver, as the driver is expected to use only link frequencies listed in DT
bindings anyway.

-- 
Kind regards,

Sakari Ailus

Re: [PATCH v13 1/2] media: dt-bindings: media: i2c: Document OV02A10 bindings

[Dongchun Zhu]

Hi Tomasz, Sakari,

Thanks for digging into the imperfections.

On Mon, 2020-08-31 at 19:06 +0300, Sakari Ailus wrote:
> Hi Tomasz,
> 
> Thanks for dressing this into words.
> 
> On Mon, Aug 31, 2020 at 01:44:27PM +0200, Tomasz Figa wrote:
> > Hi Dongchun,
> > 
> > On Fri, Jul 10, 2020 at 12:19 PM Dongchun Zhu <dongchun.zhu@mediatek.com> wrote:
> > >
> > > Add YAML device tree binding for OV02A10 CMOS image sensor,
> > > and the relevant MAINTAINERS entries.
> > >
> > > Reviewed-by: Tomasz Figa <tfiga@chromium.org>
> > > Reviewed-by: Rob Herring <robh@kernel.org>
> > > Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > > ---
> > >  .../bindings/media/i2c/ovti,ov02a10.yaml           | 172 +++++++++++++++++++++
> > >  MAINTAINERS                                        |   7 +
> > >  2 files changed, 179 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..3a916cc
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > > @@ -0,0 +1,172 @@
> > > +# 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: divider clock
> > > +
> > > +  clock-names:
> > > +    items:
> > > +      - const: eclk
> > > +      - const: freq_mux
> > 
> > Why do we have two clocks here? Looking at the example suggests that
> > they may be the clocks of the SoC that the integration was done with.
> > However, the binding must only define the aspects of the particular
> > device, i.e. this sensor.
> > 
> > I suppose we should only have "eclk" here and it should be described
> > as "external clock for the sensor".
> > 

I cannot agree with you more, it would be fixed in next release.

> > > +
> > > +  clock-frequency:
> > > +    description:
> > > +      Frequency of the eclk clock in Hertz.
> > 
> > nit: maybe Hz?
> > 

Both shall be okay, let's use Hz instead, which seems to be more simple.

> > > +
> > > +  dovdd-supply:
> > > +    description:
> > > +      Definition of the regulator used as Digital I/O voltage supply.
> > > +
> > > +  avdd-supply:
> > > +    description:
> > > +      Definition of the regulator used as Analog voltage supply.
> > > +
> > > +  dvdd-supply:
> > > +    description:
> > > +      Definition of the regulator used as Digital core voltage supply.
> > > +
> > > +  powerdown-gpios:
> > > +    description:
> > > +      Must be the device tree identifier of the GPIO connected to the
> > > +      PD_PAD pin. This pin is used to place the OV02A10 into standby mode
> > > +      or shutdown mode. As the line needs to be high for the powerdown mode
> > > +      to be active, it should be marked GPIO_ACTIVE_HIGH.
> > > +    maxItems: 1
> > > +
> > > +  reset-gpios:
> > > +    description:
> > > +      Must be the device tree identifier of the GPIO connected to the
> > > +      RST_PD pin. If specified, it will be asserted during driver probe.
> > > +      As the line needs to be low for the reset to be active, it should be
> > > +      marked GPIO_ACTIVE_LOW.
> > > +    maxItems: 1
> > > +
> > > +  rotation:
> > > +    description:
> > > +      Definition of the sensor's placement.
> > > +    allOf:
> > > +      - $ref: "/schemas/types.yaml#/definitions/uint32"
> > > +      - enum:
> > > +          - 0    # Sensor Mounted Upright
> > > +          - 180  # Sensor Mounted Upside Down
> > > +        default: 0
> > > +
> > > +  ovti,mipi-tx-speed:
> > > +    description:
> > > +      Indication of MIPI transmission speed select, which is to control D-PHY
> > > +      timing setting by adjusting MIPI clock voltage to improve the clock
> > > +      driver capability.
> > 
> > The description says that the value adjusts "MIPI clock voltage".
> > Should the property be renamed to "ovti,mipi-clock-voltage"?
> > 

Sure, mipi-clock-voltage seems more clear, perfect naming :-)

> > > +    allOf:
> > > +      - $ref: "/schemas/types.yaml#/definitions/uint32"
> > > +      - enum:
> > > +          - 0    #  20MHz -  30MHz
> > > +          - 1    #  30MHz -  50MHz
> > > +          - 2    #  50MHz -  75MHz
> > > +          - 3    #  75MHz - 100MHz
> > > +          - 4    # 100MHz - 130MHz
> > > +        default: 3
> > > +
> > 
> > I've discussed this on IRC with Sakari. It sounds like this works as
> > is for us because the driver currently only supports 1 mode, always
> > running the link at 390 MHz. This won't scale if one intends to add
> > more modes, because DT can't be expected to be updated when the driver
> > changes. The two are expected to be separate and backwards compatible.
> > 
> > I think we could model this in DT as an array of <link speed, clock
> > voltage> pairs. Similarly to the OPP bindings [1]. An example to have
> > all link speeds up to 390 MHz use the value 4:
> > 
> > ovti,mipi-clock-voltages = <
> >               /* KHz         clock voltage unit */
> >                  390000    4
> > >;
> > 
> > if one wants to select different voltage for different link, they
> > could do so as well. With the example below, the driver should
> > configure "3" for link frequencies <= 150 MHz and "4" for > 150 MHz <=
> > 390 MHz. Link frequencies > 390 MHz should be disallowed.
> > 
> > ovti,mipi-clock-voltages = <
> >               /* KHz         clock voltage unit */
> >                  150000    3
> >                  390000    4
> > >;
> > 
> > What do you think?
> 

So now we define the MIPI clock voltage (unit) as one function of link
frequency?

For current sensor mode (1600x1200, 390MHz link frequency), we then
shall always use the value 4 to configure the MIPI transmission speed
selection (P1:0xA1). Am I correct in thinking that?

> One more note on my proposal: use the index of the link frequency to access
> the ovti,mipi-clock-voltages array. That should be more simple for the
> driver, as the driver is expected to use only link frequencies listed in DT
> bindings anyway.
> 

Good idea! That's exactly what I mean.
Just submitted one draft change to handle the new property in DT.
@Sakari @Tomasz please help to review it.
https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2387980/1/drivers/media/i2c/ov02a10.c#883

Re: [PATCH v13 1/2] media: dt-bindings: media: i2c: Document OV02A10 bindings

[Sakari Ailus]

On Tue, Sep 01, 2020 at 10:35:37PM +0800, Dongchun Zhu wrote:
> Hi Tomasz, Sakari,
> 
> Thanks for digging into the imperfections.
> 
> On Mon, 2020-08-31 at 19:06 +0300, Sakari Ailus wrote:
> > Hi Tomasz,
> > 
> > Thanks for dressing this into words.
> > 
> > On Mon, Aug 31, 2020 at 01:44:27PM +0200, Tomasz Figa wrote:
> > > Hi Dongchun,
> > > 
> > > On Fri, Jul 10, 2020 at 12:19 PM Dongchun Zhu <dongchun.zhu@mediatek.com> wrote:
> > > >
> > > > Add YAML device tree binding for OV02A10 CMOS image sensor,
> > > > and the relevant MAINTAINERS entries.
> > > >
> > > > Reviewed-by: Tomasz Figa <tfiga@chromium.org>
> > > > Reviewed-by: Rob Herring <robh@kernel.org>
> > > > Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > > > ---
> > > >  .../bindings/media/i2c/ovti,ov02a10.yaml           | 172 +++++++++++++++++++++
> > > >  MAINTAINERS                                        |   7 +
> > > >  2 files changed, 179 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..3a916cc
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > > > @@ -0,0 +1,172 @@
> > > > +# 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: divider clock
> > > > +
> > > > +  clock-names:
> > > > +    items:
> > > > +      - const: eclk
> > > > +      - const: freq_mux
> > > 
> > > Why do we have two clocks here? Looking at the example suggests that
> > > they may be the clocks of the SoC that the integration was done with.
> > > However, the binding must only define the aspects of the particular
> > > device, i.e. this sensor.
> > > 
> > > I suppose we should only have "eclk" here and it should be described
> > > as "external clock for the sensor".
> > > 
> 
> I cannot agree with you more, it would be fixed in next release.
> 
> > > > +
> > > > +  clock-frequency:
> > > > +    description:
> > > > +      Frequency of the eclk clock in Hertz.
> > > 
> > > nit: maybe Hz?
> > > 
> 
> Both shall be okay, let's use Hz instead, which seems to be more simple.
> 
> > > > +
> > > > +  dovdd-supply:
> > > > +    description:
> > > > +      Definition of the regulator used as Digital I/O voltage supply.
> > > > +
> > > > +  avdd-supply:
> > > > +    description:
> > > > +      Definition of the regulator used as Analog voltage supply.
> > > > +
> > > > +  dvdd-supply:
> > > > +    description:
> > > > +      Definition of the regulator used as Digital core voltage supply.
> > > > +
> > > > +  powerdown-gpios:
> > > > +    description:
> > > > +      Must be the device tree identifier of the GPIO connected to the
> > > > +      PD_PAD pin. This pin is used to place the OV02A10 into standby mode
> > > > +      or shutdown mode. As the line needs to be high for the powerdown mode
> > > > +      to be active, it should be marked GPIO_ACTIVE_HIGH.
> > > > +    maxItems: 1
> > > > +
> > > > +  reset-gpios:
> > > > +    description:
> > > > +      Must be the device tree identifier of the GPIO connected to the
> > > > +      RST_PD pin. If specified, it will be asserted during driver probe.
> > > > +      As the line needs to be low for the reset to be active, it should be
> > > > +      marked GPIO_ACTIVE_LOW.
> > > > +    maxItems: 1
> > > > +
> > > > +  rotation:
> > > > +    description:
> > > > +      Definition of the sensor's placement.
> > > > +    allOf:
> > > > +      - $ref: "/schemas/types.yaml#/definitions/uint32"
> > > > +      - enum:
> > > > +          - 0    # Sensor Mounted Upright
> > > > +          - 180  # Sensor Mounted Upside Down
> > > > +        default: 0
> > > > +
> > > > +  ovti,mipi-tx-speed:
> > > > +    description:
> > > > +      Indication of MIPI transmission speed select, which is to control D-PHY
> > > > +      timing setting by adjusting MIPI clock voltage to improve the clock
> > > > +      driver capability.
> > > 
> > > The description says that the value adjusts "MIPI clock voltage".
> > > Should the property be renamed to "ovti,mipi-clock-voltage"?
> > > 
> 
> Sure, mipi-clock-voltage seems more clear, perfect naming :-)
> 
> > > > +    allOf:
> > > > +      - $ref: "/schemas/types.yaml#/definitions/uint32"
> > > > +      - enum:
> > > > +          - 0    #  20MHz -  30MHz
> > > > +          - 1    #  30MHz -  50MHz
> > > > +          - 2    #  50MHz -  75MHz
> > > > +          - 3    #  75MHz - 100MHz
> > > > +          - 4    # 100MHz - 130MHz
> > > > +        default: 3
> > > > +
> > > 
> > > I've discussed this on IRC with Sakari. It sounds like this works as
> > > is for us because the driver currently only supports 1 mode, always
> > > running the link at 390 MHz. This won't scale if one intends to add
> > > more modes, because DT can't be expected to be updated when the driver
> > > changes. The two are expected to be separate and backwards compatible.
> > > 
> > > I think we could model this in DT as an array of <link speed, clock
> > > voltage> pairs. Similarly to the OPP bindings [1]. An example to have
> > > all link speeds up to 390 MHz use the value 4:
> > > 
> > > ovti,mipi-clock-voltages = <
> > >               /* KHz         clock voltage unit */
> > >                  390000    4
> > > >;
> > > 
> > > if one wants to select different voltage for different link, they
> > > could do so as well. With the example below, the driver should
> > > configure "3" for link frequencies <= 150 MHz and "4" for > 150 MHz <=
> > > 390 MHz. Link frequencies > 390 MHz should be disallowed.
> > > 
> > > ovti,mipi-clock-voltages = <
> > >               /* KHz         clock voltage unit */
> > >                  150000    3
> > >                  390000    4
> > > >;
> > > 
> > > What do you think?
> > 
> 
> So now we define the MIPI clock voltage (unit) as one function of link
> frequency?
> 
> For current sensor mode (1600x1200, 390MHz link frequency), we then
> shall always use the value 4 to configure the MIPI transmission speed
> selection (P1:0xA1). Am I correct in thinking that?
> 
> > One more note on my proposal: use the index of the link frequency to access
> > the ovti,mipi-clock-voltages array. That should be more simple for the
> > driver, as the driver is expected to use only link frequencies listed in DT
> > bindings anyway.
> > 
> 
> Good idea! That's exactly what I mean.
> Just submitted one draft change to handle the new property in DT.
> @Sakari @Tomasz please help to review it.
> https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2387980/1/drivers/media/i2c/ov02a10.c#883

Please send it to the list.

-- 
Sakari Ailus