[PATCH v8 0/2] Add support Add support for Omnivision OV56477

[PATCH v8 0/2] Add support Add support for Omnivision OV56477

[Ramiro Oliveira]

Hello,

This patchset adds support for the Omnivision OV5647 sensor.

At the moment it only supports 640x480 in RAW 8.

This is the eighth version of the OV5647 camera driver patchset.

v8:
 - Remove a part of the initialization procedure which wasn't doing 
 anything
 - Check for i2c read/writes return values
 - Add stream_on/off functions

v7:
 - Remove "0x" and leading 0 from DT documentation examples

v6:
 - Add example to DT documentation
 - Remove data-lanes and clock-lane property from DT
 - Add external clock property to DT
 - Order includes
 - Remove unused variables and functions
 - Add external clock handling
 - Add power on counter
 - Change from g/s_parm to g/s_frame_interval

v5:
 - Refactor code 
 - Change comments
 - Add missing error handling in some functions

v4: 
 - Add correct license
 - Revert debugging info to generic infrastructure
 - Turn defines into enums
 - Correct code style issues
 - Remove unused defines
 - Make sure all errors where being handled
 - Rename some functions to make code more readable
 - Add some debugging info

v3: 
 - No changes. Re-submitted due to lack of responses

v2: 
 - Corrections in DT documentation

Ramiro Oliveira (2):
  Add OV5647 device tree documentation
  Add support for OV5647 sensor.

 .../devicetree/bindings/media/i2c/ov5647.txt       |  35 +
 MAINTAINERS                                        |   7 +
 drivers/media/i2c/Kconfig                          |  12 +
 drivers/media/i2c/Makefile                         |   1 +
 drivers/media/i2c/ov5647.c                         | 736 +++++++++++++++++++++
 5 files changed, 791 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/ov5647.txt
 create mode 100644 drivers/media/i2c/ov5647.c

-- 
2.11.0

[PATCH v8 1/2] Add OV5647 device tree documentation

[Ramiro Oliveira]

Create device tree bindings documentation.

Signed-off-by: Ramiro Oliveira <roliveir@synopsys.com>
Acked-by: Rob Herring <robh@kernel.org>
---
 .../devicetree/bindings/media/i2c/ov5647.txt       | 35 ++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/ov5647.txt

diff --git a/Documentation/devicetree/bindings/media/i2c/ov5647.txt b/Documentation/devicetree/bindings/media/i2c/ov5647.txt
new file mode 100644
index 000000000000..57fd40036c26
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/i2c/ov5647.txt
@@ -0,0 +1,35 @@
+Omnivision OV5647 raw image sensor
+---------------------------------
+
+OV5647 is a raw image sensor with MIPI CSI-2 and CCP2 image data interfaces
+and CCI (I2C compatible) control bus.
+
+Required properties:
+
+- compatible		: "ovti,ov5647".
+- reg			: I2C slave address of the sensor.
+- clocks		: Reference to the xclk clock.
+- clock-names		: Should be "xclk".
+- clock-frequency	: Frequency of the xclk clock.
+
+The common video interfaces bindings (see video-interfaces.txt) should be
+used to specify link to the image data receiver. The OV5647 device
+node should contain one 'port' child node with an 'endpoint' subnode.
+
+Example:
+
+	i2c@2000 {
+		...
+		ov: camera@36 {
+			compatible = "ovti,ov5647";
+			reg = <0x36>;
+			clocks = <&camera_clk>;
+			clock-names = "xclk";
+			clock-frequency = <30000000>;
+			port {
+				camera_1: endpoint {
+					remote-endpoint = <&csi1_ep1>;
+				};
+			};
+		};
+	};
-- 
2.11.0

[PATCH v8 2/2] Add support for OV5647 sensor.

[Ramiro Oliveira]

Modes supported:
 - 640x480 RAW 8

Signed-off-by: Ramiro Oliveira <roliveir@synopsys.com>
---
 MAINTAINERS                |   7 +
 drivers/media/i2c/Kconfig  |  12 +
 drivers/media/i2c/Makefile |   1 +
 drivers/media/i2c/ov5647.c | 736 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 756 insertions(+)
 create mode 100644 drivers/media/i2c/ov5647.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 8e7e8d7855ee..7bbca271acc8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9109,6 +9109,13 @@ M:	Harald Welte <laforge@gnumonks.org>
 S:	Maintained
 F:	drivers/char/pcmcia/cm4040_cs.*
 
+OMNIVISION OV5647 SENSOR DRIVER
+M:	Ramiro Oliveira <roliveir@synopsys.com>
+L:	linux-media@vger.kernel.org
+T:	git git://linuxtv.org/media_tree.git
+S:	Maintained
+F:	drivers/media/i2c/ov5647.c
+
 OMNIVISION OV7670 SENSOR DRIVER
 M:	Jonathan Corbet <corbet@lwn.net>
 L:	linux-media@vger.kernel.org
diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index cee1dae6e014..ac388be5f9a8 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -531,6 +531,18 @@ config VIDEO_OV2659
 	  To compile this driver as a module, choose M here: the
 	  module will be called ov2659.
 
+config VIDEO_OV5647
+	tristate "OmniVision OV5647 sensor support"
+	depends on OF
+	depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
+	depends on MEDIA_CAMERA_SUPPORT
+	---help---
+	  This is a Video4Linux2 sensor-level driver for the OmniVision
+	  OV5647 camera.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ov5647.
+
 config VIDEO_OV7640
 	tristate "OmniVision OV7640 sensor support"
 	depends on I2C && VIDEO_V4L2
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index 5bc7bbeb5499..ef2ccf65f94c 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -83,3 +83,4 @@ obj-$(CONFIG_VIDEO_IR_I2C)  += ir-kbd-i2c.o
 obj-$(CONFIG_VIDEO_ML86V7667)	+= ml86v7667.o
 obj-$(CONFIG_VIDEO_OV2659)	+= ov2659.o
 obj-$(CONFIG_VIDEO_TC358743)	+= tc358743.o
+obj-$(CONFIG_VIDEO_OV5647)	+= ov5647.o
diff --git a/drivers/media/i2c/ov5647.c b/drivers/media/i2c/ov5647.c
new file mode 100644
index 000000000000..d6b5dcaa00d3
--- /dev/null
+++ b/drivers/media/i2c/ov5647.c
@@ -0,0 +1,736 @@
+/*
+ * A V4L2 driver for OmniVision OV5647 cameras.
+ *
+ * Based on Samsung S5K6AAFX SXGA 1/6" 1.3M CMOS Image Sensor driver
+ * Copyright (C) 2011 Sylwester Nawrocki <s.nawrocki@samsung.com>
+ *
+ * Based on Omnivision OV7670 Camera Driver
+ * Copyright (C) 2006-7 Jonathan Corbet <corbet@lwn.net>
+ *
+ * Copyright (C) 2016, Synopsys, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed .as is. WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/videodev2.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-image-sizes.h>
+#include <media/v4l2-mediabus.h>
+#include <media/v4l2-of.h>
+
+#define SENSOR_NAME "ov5647"
+
+#define OV5647_SW_RESET		0x1003
+#define OV5647_REG_CHIPID_H	0x300A
+#define OV5647_REG_CHIPID_L	0x300B
+
+#define REG_TERM 0xfffe
+#define VAL_TERM 0xfe
+#define REG_DLY  0xffff
+
+#define OV5647_ROW_START		0x01
+#define OV5647_ROW_START_MIN		0
+#define OV5647_ROW_START_MAX		2004
+#define OV5647_ROW_START_DEF		54
+
+#define OV5647_COLUMN_START		0x02
+#define OV5647_COLUMN_START_MIN		0
+#define OV5647_COLUMN_START_MAX		2750
+#define OV5647_COLUMN_START_DEF		16
+
+#define OV5647_WINDOW_HEIGHT		0x03
+#define OV5647_WINDOW_HEIGHT_MIN	2
+#define OV5647_WINDOW_HEIGHT_MAX	2006
+#define OV5647_WINDOW_HEIGHT_DEF	1944
+
+#define OV5647_WINDOW_WIDTH		0x04
+#define OV5647_WINDOW_WIDTH_MIN		2
+#define OV5647_WINDOW_WIDTH_MAX		2752
+#define OV5647_WINDOW_WIDTH_DEF		2592
+
+struct regval_list {
+	u16 addr;
+	u8 data;
+};
+
+struct cfg_array {
+	struct regval_list *regs;
+	int size;
+};
+
+struct ov5647 {
+	struct device			*dev;
+	struct v4l2_subdev		sd;
+	struct media_pad		pad;
+	struct mutex			lock;
+	struct v4l2_mbus_framefmt	format;
+	unsigned int			width;
+	unsigned int			height;
+	int				power_count;
+	struct clk			*xclk;
+	/* External clock frequency currently supported is 30MHz */
+	u32				xclk_freq;
+};
+
+static inline struct ov5647 *to_state(struct v4l2_subdev *sd)
+{
+	return container_of(sd, struct ov5647, sd);
+}
+
+static struct regval_list sensor_oe_disable_regs[] = {
+	{0x3000, 0x00},
+	{0x3001, 0x00},
+	{0x3002, 0x00},
+};
+
+static struct regval_list sensor_oe_enable_regs[] = {
+	{0x3000, 0x0f},
+	{0x3001, 0xff},
+	{0x3002, 0xe4},
+};
+
+static struct regval_list ov5647_640x480[] = {
+	{0x0100, 0x00},
+	{0x0103, 0x01},
+	{0x3034, 0x08},
+	{0x3035, 0x21},
+	{0x3036, 0x46},
+	{0x303c, 0x11},
+	{0x3106, 0xf5},
+	{0x3821, 0x07},
+	{0x3820, 0x41},
+	{0x3827, 0xec},
+	{0x370c, 0x0f},
+	{0x3612, 0x59},
+	{0x3618, 0x00},
+	{0x5000, 0x06},
+	{0x5001, 0x01},
+	{0x5002, 0x41},
+	{0x5003, 0x08},
+	{0x5a00, 0x08},
+	{0x3000, 0x00},
+	{0x3001, 0x00},
+	{0x3002, 0x00},
+	{0x3016, 0x08},
+	{0x3017, 0xe0},
+	{0x3018, 0x44},
+	{0x301c, 0xf8},
+	{0x301d, 0xf0},
+	{0x3a18, 0x00},
+	{0x3a19, 0xf8},
+	{0x3c01, 0x80},
+	{0x3b07, 0x0c},
+	{0x380c, 0x07},
+	{0x380d, 0x68},
+	{0x380e, 0x03},
+	{0x380f, 0xd8},
+	{0x3814, 0x31},
+	{0x3815, 0x31},
+	{0x3708, 0x64},
+	{0x3709, 0x52},
+	{0x3808, 0x02},
+	{0x3809, 0x80},
+	{0x380a, 0x01},
+	{0x380b, 0xE0},
+	{0x3801, 0x00},
+	{0x3802, 0x00},
+	{0x3803, 0x00},
+	{0x3804, 0x0a},
+	{0x3805, 0x3f},
+	{0x3806, 0x07},
+	{0x3807, 0xa1},
+	{0x3811, 0x08},
+	{0x3813, 0x02},
+	{0x3630, 0x2e},
+	{0x3632, 0xe2},
+	{0x3633, 0x23},
+	{0x3634, 0x44},
+	{0x3636, 0x06},
+	{0x3620, 0x64},
+	{0x3621, 0xe0},
+	{0x3600, 0x37},
+	{0x3704, 0xa0},
+	{0x3703, 0x5a},
+	{0x3715, 0x78},
+	{0x3717, 0x01},
+	{0x3731, 0x02},
+	{0x370b, 0x60},
+	{0x3705, 0x1a},
+	{0x3f05, 0x02},
+	{0x3f06, 0x10},
+	{0x3f01, 0x0a},
+	{0x3a08, 0x01},
+	{0x3a09, 0x27},
+	{0x3a0a, 0x00},
+	{0x3a0b, 0xf6},
+	{0x3a0d, 0x04},
+	{0x3a0e, 0x03},
+	{0x3a0f, 0x58},
+	{0x3a10, 0x50},
+	{0x3a1b, 0x58},
+	{0x3a1e, 0x50},
+	{0x3a11, 0x60},
+	{0x3a1f, 0x28},
+	{0x4001, 0x02},
+	{0x4004, 0x02},
+	{0x4000, 0x09},
+	{0x4837, 0x24},
+	{0x4050, 0x6e},
+	{0x4051, 0x8f},
+	{0x0100, 0x01},
+};
+
+/**
+ * @short I2C Write operation
+ * @param[in] i2c_client I2C client
+ * @param[in] reg register address
+ * @param[in] val value to write
+ * @return Error code
+ */
+static int ov5647_write(struct v4l2_subdev *sd, u16 reg, u8 val)
+{
+	int ret;
+	unsigned char data[3] = { reg >> 8, reg & 0xff, val};
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+	ret = i2c_master_send(client, data, 3);
+	if (ret != 3) {
+		dev_dbg(&client->dev, "%s: i2c write error, reg: %x\n",
+				__func__, reg);
+		return ret < 0 ? ret : -EIO;
+	}
+	return 0;
+}
+
+/**
+ * @short I2C Read operation
+ * @param[in] i2c_client I2C client
+ * @param[in] reg register address
+ * @param[out] val value read
+ * @return Error code
+ */
+static int ov5647_read(struct v4l2_subdev *sd, u16 reg, u8 *val)
+{
+	int ret;
+	unsigned char data_w[2] = { reg >> 8, reg & 0xff };
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+	ret = i2c_master_send(client, data_w, 2);
+
+	if (ret < 2) {
+		dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
+			__func__, reg);
+		return ret < 0 ? ret : -EIO;
+	}
+
+	ret = i2c_master_recv(client, val, 1);
+
+	if (ret < 1) {
+		dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
+				__func__, reg);
+		return ret < 0 ? ret : -EIO;
+	}
+	return 0;
+}
+
+static int ov5647_write_array(struct v4l2_subdev *sd,
+				struct regval_list *regs, int array_size)
+{
+	int i = 0;
+	int ret = 0;
+
+	if (!regs)
+		return -EINVAL;
+
+	while (i < array_size) {
+		ret = ov5647_write(sd, regs->addr, regs->data);
+		if (ret < 0)
+			return ret;
+		i++;
+		regs++;
+	}
+	return 0;
+}
+
+static int ov5647_set_virtual_channel(struct v4l2_subdev *sd, int channel)
+{
+	u8 channel_id;
+	int ret = 0;
+
+	ret = ov5647_read(sd, 0x4814, &channel_id);
+	if (ret < 0)
+		return ret;
+
+	channel_id &= ~(3 << 6);
+	return ov5647_write(sd, 0x4814, channel_id | (channel << 6));
+}
+
+static int ov5647_stream_on(struct v4l2_subdev *sd)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+	ov5647_write(sd, 0x4202, 0x00);
+
+	dev_dbg(&client->dev, "Stream on");
+
+	return ov5647_write(sd, 0x300D, 0x00);
+}
+
+static int ov5647_stream_off(struct v4l2_subdev *sd)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+	ov5647_write(sd, 0x4202, 0x0f);
+
+	dev_dbg(&client->dev, "Stream off");
+
+	return ov5647_write(sd, 0x300D, 0x01);
+}
+
+/**
+ * @short Set SW standby
+ * @param[in] sd v4l2 sd
+ * @param[in] stanby standby mode status (on or off)
+ * @return Error code
+ */
+static int set_sw_standby(struct v4l2_subdev *sd, bool standby)
+{
+	int ret;
+	unsigned char rdval;
+
+	ret = ov5647_read(sd, 0x0100, &rdval);
+	if (ret != 0)
+		return ret;
+
+	if (standby)
+		rdval &= 0xfe;
+	else
+		rdval |= 0x01;
+
+	return ov5647_write(sd, 0x0100, rdval);
+}
+
+/**
+ * @short Initialize sensor
+ * @param[in] sd v4l2 subdev
+ * @param[in] val not used
+ * @return Error code
+ */
+static int __sensor_init(struct v4l2_subdev *sd)
+{
+	int ret;
+	u8 resetval;
+	u8 rdval;
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+	dev_dbg(&client->dev, "sensor init\n");
+
+	ret = ov5647_read(sd, 0x0100, &rdval);
+	if (ret != 0)
+		return ret;
+
+	ret = ov5647_write_array(sd, ov5647_640x480,
+					ARRAY_SIZE(ov5647_640x480));
+	if (ret < 0) {
+		dev_err(&client->dev, "write sensor default regs error\n");
+		return ret;
+	}
+
+	ret = ov5647_set_virtual_channel(sd, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = ov5647_read(sd, 0x0100, &resetval);
+	if (ret < 0)
+		return ret;
+
+	if (!(resetval & 0x01)) {
+		dev_err(&client->dev, "Device was in SW standby");
+		ret = ov5647_write(sd, 0x0100, 0x01);
+		if (ret < 0)
+			return ret;
+	}
+
+	return ov5647_write(sd, 0x4800, 0x04);
+}
+
+/**
+ * @short Control sensor power state
+ * @param[in] sd v4l2 subdev
+ * @param[in] on Sensor power
+ * @return Error code
+ */
+static int sensor_power(struct v4l2_subdev *sd, int on)
+{
+	int ret;
+	struct ov5647 *ov5647 = to_state(sd);
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+	ret = 0;
+	mutex_lock(&ov5647->lock);
+
+	if (on && !ov5647->power_count)	{
+		dev_dbg(&client->dev, "OV5647 power on\n");
+
+		clk_set_rate(ov5647->xclk, ov5647->xclk_freq);
+
+		ret = clk_prepare_enable(ov5647->xclk);
+		if (ret < 0) {
+			dev_err(ov5647->dev, "clk prepare enable failed\n");
+			goto out;
+		}
+
+		ret = ov5647_write_array(sd, sensor_oe_enable_regs,
+				ARRAY_SIZE(sensor_oe_enable_regs));
+		if (ret < 0) {
+			clk_disable_unprepare(ov5647->xclk);
+			dev_err(&client->dev,
+				"write sensor_oe_enable_regs error\n");
+			goto out;
+		}
+
+		ret = __sensor_init(sd);
+		if (ret < 0) {
+			clk_disable_unprepare(ov5647->xclk);
+			dev_err(&client->dev,
+				"Camera not available, check Power\n");
+			goto out;
+		}
+	} else if (!on && ov5647->power_count == 1) {
+		dev_dbg(&client->dev, "OV5647 power off\n");
+
+		dev_dbg(&client->dev, "disable oe\n");
+		ret = ov5647_write_array(sd, sensor_oe_disable_regs,
+				ARRAY_SIZE(sensor_oe_disable_regs));
+
+		if (ret < 0)
+			dev_dbg(&client->dev, "disable oe failed\n");
+
+		ret = set_sw_standby(sd, true);
+
+		if (ret < 0)
+			dev_dbg(&client->dev, "soft stby failed\n");
+
+		clk_disable_unprepare(ov5647->xclk);
+	}
+
+	/* Update the power count. */
+	ov5647->power_count += on ? 1 : -1;
+	WARN_ON(ov5647->power_count < 0);
+
+out:
+	mutex_unlock(&ov5647->lock);
+
+	return ret;
+}
+
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+/**
+ * @short Get register value
+ * @param[in] sd v4l2 subdev
+ * @param[in] reg register struct
+ * @return Error code
+ */
+static int sensor_get_register(struct v4l2_subdev *sd,
+				struct v4l2_dbg_register *reg)
+{
+	unsigned char val = 0;
+	int ret;
+
+	ret = ov5647_read(sd, reg->reg & 0xff, &val);
+	if (ret != 0)
+		return ret;
+
+	reg->val = val;
+	reg->size = 1;
+
+	return ret;
+}
+
+/**
+ * @short Set register value
+ * @param[in] sd v4l2 subdev
+ * @param[in] reg register struct
+ * @return Error code
+ */
+static int sensor_set_register(struct v4l2_subdev *sd,
+				const struct v4l2_dbg_register *reg)
+{
+	return ov5647_write(sd, reg->reg & 0xff, reg->val & 0xff);
+}
+#endif
+
+/**
+ * @short Subdev core operations registration
+ */
+static const struct v4l2_subdev_core_ops subdev_core_ops = {
+	.s_power		= sensor_power,
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+	.g_register		= sensor_get_register,
+	.s_register		= sensor_set_register,
+#endif
+};
+
+static int s_stream(struct v4l2_subdev *sd, int enable)
+{
+	if (!enable)
+		return ov5647_stream_off(sd);
+	else
+		return ov5647_stream_on(sd);
+}
+
+static const struct v4l2_subdev_video_ops subdev_video_ops = {
+	.s_stream =		s_stream,
+};
+
+
+static int enum_mbus_code(struct v4l2_subdev *sd,
+				struct v4l2_subdev_pad_config *cfg,
+				struct v4l2_subdev_mbus_code_enum *code)
+{
+	if (code->index > 0)
+		return -EINVAL;
+
+	code->code = MEDIA_BUS_FMT_SBGGR8_1X8;
+
+	return 0;
+}
+
+static const struct v4l2_subdev_pad_ops subdev_pad_ops = {
+	.enum_mbus_code =	enum_mbus_code,
+};
+
+/**
+ * @short Subdev operations registration
+ *
+ */
+static const struct v4l2_subdev_ops subdev_ops = {
+	.core		= &subdev_core_ops,
+	.video		= &subdev_video_ops,
+	.pad		= &subdev_pad_ops,
+};
+
+/**
+ * @short Detect camera version and model
+ * @param[in] sd v4l2 subdev
+ * @return Error code
+ */
+static int ov5647_detect(struct v4l2_subdev *sd)
+{
+	unsigned char read;
+	int ret;
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+	ret = ov5647_write(sd, OV5647_SW_RESET, 0x01);
+	if (ret < 0)
+		return ret;
+
+	ret = ov5647_read(sd, OV5647_REG_CHIPID_H, &read);
+	if (ret < 0)
+		return ret;
+
+	if (read != 0x56) {
+		dev_err(&client->dev, "Wrong model version detected");
+		return -ENODEV;
+	}
+
+	ret = ov5647_read(sd, OV5647_REG_CHIPID_L, &read);
+	if (ret < 0)
+		return ret;
+
+	if (read != 0x47) {
+		dev_err(&client->dev, "Wrong model version detected");
+		return -ENODEV;
+	}
+
+	return ov5647_write(sd, OV5647_SW_RESET, 0x00);
+}
+
+/**
+ * @short Detect if camera is registered
+ * @param[in] sd v4l2 subdev
+ * @return Error code
+ */
+static int ov5647_registered(struct v4l2_subdev *sd)
+{
+	return 0;
+}
+
+/**
+ * @short Open device
+ * @param[in] sd v4l2 subdev
+ * @param[in] fh v4l2 file handler
+ * @return Error code
+ */
+static int ov5647_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	struct v4l2_mbus_framefmt *format =
+				v4l2_subdev_get_try_format(sd, fh->pad, 0);
+	struct v4l2_rect *crop =
+				v4l2_subdev_get_try_crop(sd, fh->pad, 0);
+
+	crop->left = OV5647_COLUMN_START_DEF;
+	crop->top = OV5647_ROW_START_DEF;
+	crop->width = OV5647_WINDOW_WIDTH_DEF;
+	crop->height = OV5647_WINDOW_HEIGHT_DEF;
+
+	format->code = MEDIA_BUS_FMT_SBGGR8_1X8;
+
+	format->width = OV5647_WINDOW_WIDTH_DEF;
+	format->height = OV5647_WINDOW_HEIGHT_DEF;
+	format->field = V4L2_FIELD_NONE;
+	format->colorspace = V4L2_COLORSPACE_SRGB;
+
+	return sensor_power(sd, true);
+}
+
+/**
+ * @short Open device
+ * @param[in] sd v4l2 subdev
+ * @param[in] fh v4l2 file handler
+ * @return Error code
+ */
+static int ov5647_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	return sensor_power(sd, false);
+}
+
+/**
+ * @short Subdev internal operations registration
+ *
+ */
+static const struct v4l2_subdev_internal_ops ov5647_subdev_internal_ops = {
+	.registered = ov5647_registered,
+	.open = ov5647_open,
+	.close = ov5647_close,
+};
+
+/**
+ * @short Initialization routine - Entry point of the driver
+ * @param[in] client pointer to the i2c client structure
+ * @param[in] id pointer to the i2c device id structure
+ * @return 0 on success and a negative number on failure
+ */
+static int ov5647_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct ov5647 *sensor;
+	int ret;
+	struct v4l2_subdev *sd;
+
+	dev_info(&client->dev, "Installing OmniVision OV5647 camera driver\n");
+
+	sensor = devm_kzalloc(dev, sizeof(*sensor), GFP_KERNEL);
+	if (sensor == NULL)
+		return -ENOMEM;
+
+	/* get system clock (xclk) */
+	sensor->xclk = devm_clk_get(dev, "xclk");
+	if (IS_ERR(sensor->xclk)) {
+		dev_err(dev, "could not get xclk");
+		return PTR_ERR(sensor->xclk);
+	}
+
+	ret = of_property_read_u32(dev->of_node, "clock-frequency",
+				    &sensor->xclk_freq);
+	if (ret) {
+		dev_err(dev, "could not get xclk frequency\n");
+		return ret;
+	}
+
+	mutex_init(&sensor->lock);
+	sensor->dev = dev;
+
+	sd = &sensor->sd;
+	v4l2_i2c_subdev_init(sd, client, &subdev_ops);
+	sensor->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+
+	sensor->pad.flags = MEDIA_PAD_FL_SOURCE;
+	sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
+	ret = media_entity_pads_init(&sd->entity, 1, &sensor->pad);
+	if (ret < 0)
+		goto mutex_remove;
+
+	ret = ov5647_detect(sd);
+	if (ret < 0)
+		goto error;
+
+	ret = v4l2_async_register_subdev(sd);
+	if (ret < 0)
+		goto error;
+
+	return 0;
+error:
+	media_entity_cleanup(&sd->entity);
+mutex_remove:
+	mutex_destroy(&sensor->lock);
+	return ret;
+}
+
+/**
+ * @short Exit routine - Exit point of the driver
+ * @param[in] client pointer to the i2c client structure
+ * @return 0 on success and a negative number on failure
+ */
+static int ov5647_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct ov5647 *ov5647 = to_state(sd);
+
+	v4l2_async_unregister_subdev(&ov5647->sd);
+	media_entity_cleanup(&ov5647->sd.entity);
+	v4l2_device_unregister_subdev(sd);
+	mutex_destroy(&ov5647->lock);
+
+	return 0;
+}
+
+static const struct i2c_device_id ov5647_id[] = {
+	{ "ov5647", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ov5647_id);
+
+#if IS_ENABLED(CONFIG_OF)
+static const struct of_device_id ov5647_of_match[] = {
+	{ .compatible = "ovti,ov5647" },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, ov5647_of_match);
+#endif
+
+/**
+ * @short i2c driver structure
+ */
+static struct i2c_driver ov5647_driver = {
+	.driver = {
+		.of_match_table = of_match_ptr(ov5647_of_match),
+		.owner	= THIS_MODULE,
+		.name	= "ov5647",
+	},
+	.probe		= ov5647_probe,
+	.remove		= ov5647_remove,
+	.id_table	= ov5647_id,
+};
+
+module_i2c_driver(ov5647_driver);
+
+MODULE_AUTHOR("Ramiro Oliveira <roliveir@synopsys.com>");
+MODULE_DESCRIPTION("A low-level driver for OmniVision ov5647 sensors");
+MODULE_LICENSE("GPL v2");
-- 
2.11.0

Re: [PATCH v8 2/2] Add support for OV5647 sensor.

[Vladimir Zapolskiy]

Hello Ramiro,

On 02/13/2017 01:25 PM, Ramiro Oliveira wrote:
> Modes supported:
>  - 640x480 RAW 8
> 

It is a pretty short commit message, please consider to write a couple
of words about the sensor.

> Signed-off-by: Ramiro Oliveira <roliveir@synopsys.com>
> ---

[snip]

> +
> +struct cfg_array {
> +	struct regval_list *regs;
> +	int size;
> +};

struct cfg_array is apparently unused.

> +
> +/**
> + * @short I2C Write operation
> + * @param[in] i2c_client I2C client
> + * @param[in] reg register address
> + * @param[in] val value to write
> + * @return Error code
> + */
> +static int ov5647_write(struct v4l2_subdev *sd, u16 reg, u8 val)
> +{

The comment contents is probably outdated, because it does not describe
the function input arguments properly.

> +	int ret;
> +	unsigned char data[3] = { reg >> 8, reg & 0xff, val};
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ret = i2c_master_send(client, data, 3);
> +	if (ret != 3) {
> +		dev_dbg(&client->dev, "%s: i2c write error, reg: %x\n",
> +				__func__, reg);
> +		return ret < 0 ? ret : -EIO;

Here i2c_master_send() returns only to a negative error or '3', thus
the check is redundant.

Please do 'return ret';

> +	}
> +	return 0;
> +}
> +
> +/**
> + * @short I2C Read operation
> + * @param[in] i2c_client I2C client
> + * @param[in] reg register address
> + * @param[out] val value read
> + * @return Error code
> + */
> +static int ov5647_read(struct v4l2_subdev *sd, u16 reg, u8 *val)
> +{

Same as above, the comment must be updated.

> +	int ret;
> +	unsigned char data_w[2] = { reg >> 8, reg & 0xff };
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ret = i2c_master_send(client, data_w, 2);
> +
> +	if (ret < 2) {
> +		dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
> +			__func__, reg);
> +		return ret < 0 ? ret : -EIO;


Here i2c_master_send() returns only to a negative error or '2', thus
the check is redundant.

Please do 'return ret';

> +	}
> +
> +	ret = i2c_master_recv(client, val, 1);
> +
> +	if (ret < 1) {
> +		dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
> +				__func__, reg);
> +		return ret < 0 ? ret : -EIO;

Here i2c_master_recv() returns only to a negative error or '1', thus
the check is redundant.

Please do 'return ret';

> +	}
> +	return 0;
> +}
> +
> +static int ov5647_write_array(struct v4l2_subdev *sd,
> +				struct regval_list *regs, int array_size)
> +{
> +	int i = 0;
> +	int ret = 0;

Please don't assign a value to 'ret' and please do declarations on a single line.

> +
> +	if (!regs)
> +		return -EINVAL;

!regs is a dead code check, please remove it.

> +
> +	while (i < array_size) {
> +		ret = ov5647_write(sd, regs->addr, regs->data);
> +		if (ret < 0)
> +			return ret;
> +		i++;
> +		regs++;
> +	}

Please do a for-loop, it will save two lines of code:

	for (i = 0; i < array_size; i++) {
		ret = ov5647_write(sd, regs[i].addr, regs[i].data);
		if (ret < 0)
			return ret;
	}

> +	return 0;
> +}
> +
> +static int ov5647_set_virtual_channel(struct v4l2_subdev *sd, int channel)
> +{
> +	u8 channel_id;
> +	int ret = 0;

Please don't assign a value to 'ret' on declaration here.

> +
> +	ret = ov5647_read(sd, 0x4814, &channel_id);
> +	if (ret < 0)
> +		return ret;
> +
> +	channel_id &= ~(3 << 6);
> +	return ov5647_write(sd, 0x4814, channel_id | (channel << 6));
> +}
> +
> +static int ov5647_stream_on(struct v4l2_subdev *sd)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ov5647_write(sd, 0x4202, 0x00);
> +
> +	dev_dbg(&client->dev, "Stream on");
> +
> +	return ov5647_write(sd, 0x300D, 0x00);
> +}
> +
> +static int ov5647_stream_off(struct v4l2_subdev *sd)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ov5647_write(sd, 0x4202, 0x0f);
> +
> +	dev_dbg(&client->dev, "Stream off");
> +
> +	return ov5647_write(sd, 0x300D, 0x01);
> +}
> +
> +/**
> + * @short Set SW standby
> + * @param[in] sd v4l2 sd
> + * @param[in] stanby standby mode status (on or off)
> + * @return Error code
> + */
> +static int set_sw_standby(struct v4l2_subdev *sd, bool standby)
> +{
> +	int ret;
> +	unsigned char rdval;

ov5647_read() return value type is 'u8', please change it here and
everywhere else in the code.

> +
> +	ret = ov5647_read(sd, 0x0100, &rdval);
> +	if (ret != 0)

if (ret < 0)

> +		return ret;
> +
> +	if (standby)
> +		rdval &= 0xfe;

Here 'rdval &= ~0x01' would be preferred to emphasize symmetry.

> +	else
> +		rdval |= 0x01;
> +
> +	return ov5647_write(sd, 0x0100, rdval);
> +}
> +
> +/**
> + * @short Initialize sensor
> + * @param[in] sd v4l2 subdev
> + * @param[in] val not used
> + * @return Error code
> + */
> +static int __sensor_init(struct v4l2_subdev *sd)

Same as above, the comment must be updated.

> +{
> +	int ret;
> +	u8 resetval;
> +	u8 rdval;
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	dev_dbg(&client->dev, "sensor init\n");
> +
> +	ret = ov5647_read(sd, 0x0100, &rdval);
> +	if (ret != 0)

if (ret < 0)

> +		return ret;
> +
> +	ret = ov5647_write_array(sd, ov5647_640x480,
> +					ARRAY_SIZE(ov5647_640x480));
> +	if (ret < 0) {
> +		dev_err(&client->dev, "write sensor default regs error\n");
> +		return ret;
> +	}
> +
> +	ret = ov5647_set_virtual_channel(sd, 0);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ov5647_read(sd, 0x0100, &resetval);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (!(resetval & 0x01)) {
> +		dev_err(&client->dev, "Device was in SW standby");
> +		ret = ov5647_write(sd, 0x0100, 0x01);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return ov5647_write(sd, 0x4800, 0x04);
> +}
> +
> +/**
> + * @short Control sensor power state
> + * @param[in] sd v4l2 subdev
> + * @param[in] on Sensor power
> + * @return Error code
> + */
> +static int sensor_power(struct v4l2_subdev *sd, int on)
> +{
> +	int ret;
> +	struct ov5647 *ov5647 = to_state(sd);
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ret = 0;
> +	mutex_lock(&ov5647->lock);
> +
> +	if (on && !ov5647->power_count)	{
> +		dev_dbg(&client->dev, "OV5647 power on\n");
> +
> +		clk_set_rate(ov5647->xclk, ov5647->xclk_freq);
> +
> +		ret = clk_prepare_enable(ov5647->xclk);
> +		if (ret < 0) {
> +			dev_err(ov5647->dev, "clk prepare enable failed\n");
> +			goto out;
> +		}
> +
> +		ret = ov5647_write_array(sd, sensor_oe_enable_regs,
> +				ARRAY_SIZE(sensor_oe_enable_regs));
> +		if (ret < 0) {
> +			clk_disable_unprepare(ov5647->xclk);
> +			dev_err(&client->dev,
> +				"write sensor_oe_enable_regs error\n");
> +			goto out;
> +		}
> +
> +		ret = __sensor_init(sd);
> +		if (ret < 0) {
> +			clk_disable_unprepare(ov5647->xclk);
> +			dev_err(&client->dev,
> +				"Camera not available, check Power\n");
> +			goto out;
> +		}
> +	} else if (!on && ov5647->power_count == 1) {
> +		dev_dbg(&client->dev, "OV5647 power off\n");
> +
> +		dev_dbg(&client->dev, "disable oe\n");
> +		ret = ov5647_write_array(sd, sensor_oe_disable_regs,
> +				ARRAY_SIZE(sensor_oe_disable_regs));
> +
> +		if (ret < 0)
> +			dev_dbg(&client->dev, "disable oe failed\n");
> +
> +		ret = set_sw_standby(sd, true);
> +
> +		if (ret < 0)
> +			dev_dbg(&client->dev, "soft stby failed\n");
> +
> +		clk_disable_unprepare(ov5647->xclk);
> +	}
> +
> +	/* Update the power count. */
> +	ov5647->power_count += on ? 1 : -1;
> +	WARN_ON(ov5647->power_count < 0);
> +
> +out:
> +	mutex_unlock(&ov5647->lock);
> +
> +	return ret;
> +}
> +
> +#ifdef CONFIG_VIDEO_ADV_DEBUG
> +/**
> + * @short Get register value
> + * @param[in] sd v4l2 subdev
> + * @param[in] reg register struct
> + * @return Error code
> + */
> +static int sensor_get_register(struct v4l2_subdev *sd,
> +				struct v4l2_dbg_register *reg)
> +{
> +	unsigned char val = 0;

ov5647_read() return value type is 'u8', please change it here and
everywhere else in the code.

Also please don't assign a value to 'val' n declaration.

> +	int ret;
> +
> +	ret = ov5647_read(sd, reg->reg & 0xff, &val);
> +	if (ret != 0)

if (ret < 0)

> +		return ret;
> +
> +	reg->val = val;
> +	reg->size = 1;
> +
> +	return ret;

return 0;

> +}
> +
> +/**
> + * @short Set register value
> + * @param[in] sd v4l2 subdev
> + * @param[in] reg register struct
> + * @return Error code
> + */
> +static int sensor_set_register(struct v4l2_subdev *sd,
> +				const struct v4l2_dbg_register *reg)
> +{
> +	return ov5647_write(sd, reg->reg & 0xff, reg->val & 0xff);
> +}
> +#endif
> +
> +/**
> + * @short Subdev core operations registration
> + */
> +static const struct v4l2_subdev_core_ops subdev_core_ops = {
> +	.s_power		= sensor_power,
> +#ifdef CONFIG_VIDEO_ADV_DEBUG
> +	.g_register		= sensor_get_register,
> +	.s_register		= sensor_set_register,
> +#endif
> +};
> +
> +static int s_stream(struct v4l2_subdev *sd, int enable)
> +{
> +	if (!enable)
> +		return ov5647_stream_off(sd);
> +	else
> +		return ov5647_stream_on(sd);

To avoid a negation please do

	if (enable)
		return ov5647_stream_on(sd);
	else
		return ov5647_stream_off(sd);

> +}
> +
> +static const struct v4l2_subdev_video_ops subdev_video_ops = {
> +	.s_stream =		s_stream,
> +};
> +
> +

Please remove one of two empty lines in a row.

> +static int enum_mbus_code(struct v4l2_subdev *sd,
> +				struct v4l2_subdev_pad_config *cfg,
> +				struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	if (code->index > 0)
> +		return -EINVAL;
> +
> +	code->code = MEDIA_BUS_FMT_SBGGR8_1X8;
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_pad_ops subdev_pad_ops = {
> +	.enum_mbus_code =	enum_mbus_code,
> +};
> +
> +/**
> + * @short Subdev operations registration
> + *
> + */
> +static const struct v4l2_subdev_ops subdev_ops = {
> +	.core		= &subdev_core_ops,
> +	.video		= &subdev_video_ops,
> +	.pad		= &subdev_pad_ops,
> +};
> +
> +/**
> + * @short Detect camera version and model
> + * @param[in] sd v4l2 subdev
> + * @return Error code
> + */
> +static int ov5647_detect(struct v4l2_subdev *sd)
> +{
> +	unsigned char read;

ov5647_read() return value type is 'u8', please change it here and
everywhere else in the code.

> +	int ret;
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ret = ov5647_write(sd, OV5647_SW_RESET, 0x01);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ov5647_read(sd, OV5647_REG_CHIPID_H, &read);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (read != 0x56) {
> +		dev_err(&client->dev, "Wrong model version detected");
> +		return -ENODEV;
> +	}
> +
> +	ret = ov5647_read(sd, OV5647_REG_CHIPID_L, &read);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (read != 0x47) {
> +		dev_err(&client->dev, "Wrong model version detected");
> +		return -ENODEV;
> +	}
> +
> +	return ov5647_write(sd, OV5647_SW_RESET, 0x00);
> +}
> +
> +/**
> + * @short Detect if camera is registered
> + * @param[in] sd v4l2 subdev
> + * @return Error code
> + */
> +static int ov5647_registered(struct v4l2_subdev *sd)
> +{
> +	return 0;
> +}
> +
> +/**
> + * @short Open device
> + * @param[in] sd v4l2 subdev
> + * @param[in] fh v4l2 file handler
> + * @return Error code
> + */
> +static int ov5647_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	struct v4l2_mbus_framefmt *format =
> +				v4l2_subdev_get_try_format(sd, fh->pad, 0);
> +	struct v4l2_rect *crop =
> +				v4l2_subdev_get_try_crop(sd, fh->pad, 0);
> +
> +	crop->left = OV5647_COLUMN_START_DEF;
> +	crop->top = OV5647_ROW_START_DEF;
> +	crop->width = OV5647_WINDOW_WIDTH_DEF;
> +	crop->height = OV5647_WINDOW_HEIGHT_DEF;
> +
> +	format->code = MEDIA_BUS_FMT_SBGGR8_1X8;
> +
> +	format->width = OV5647_WINDOW_WIDTH_DEF;
> +	format->height = OV5647_WINDOW_HEIGHT_DEF;
> +	format->field = V4L2_FIELD_NONE;
> +	format->colorspace = V4L2_COLORSPACE_SRGB;
> +
> +	return sensor_power(sd, true);
> +}
> +
> +/**
> + * @short Open device
> + * @param[in] sd v4l2 subdev
> + * @param[in] fh v4l2 file handler
> + * @return Error code
> + */
> +static int ov5647_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	return sensor_power(sd, false);
> +}
> +
> +/**
> + * @short Subdev internal operations registration
> + *
> + */
> +static const struct v4l2_subdev_internal_ops ov5647_subdev_internal_ops = {
> +	.registered = ov5647_registered,
> +	.open = ov5647_open,
> +	.close = ov5647_close,
> +};
> +
> +/**
> + * @short Initialization routine - Entry point of the driver
> + * @param[in] client pointer to the i2c client structure
> + * @param[in] id pointer to the i2c device id structure
> + * @return 0 on success and a negative number on failure
> + */
> +static int ov5647_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	struct device *dev = &client->dev;
> +	struct ov5647 *sensor;
> +	int ret;
> +	struct v4l2_subdev *sd;
> +
> +	dev_info(&client->dev, "Installing OmniVision OV5647 camera driver\n");

Please remove the informational line, it will pollute the kernel log for no
good reason.

> +
> +	sensor = devm_kzalloc(dev, sizeof(*sensor), GFP_KERNEL);
> +	if (sensor == NULL)
> +		return -ENOMEM;
> +
> +	/* get system clock (xclk) */
> +	sensor->xclk = devm_clk_get(dev, "xclk");
> +	if (IS_ERR(sensor->xclk)) {
> +		dev_err(dev, "could not get xclk");
> +		return PTR_ERR(sensor->xclk);
> +	}
> +
> +	ret = of_property_read_u32(dev->of_node, "clock-frequency",
> +				    &sensor->xclk_freq);
> +	if (ret) {
> +		dev_err(dev, "could not get xclk frequency\n");
> +		return ret;
> +	}
> +
> +	mutex_init(&sensor->lock);
> +	sensor->dev = dev;

sensor->dev is unused, please remove it from the 'struct ov5647' declaration.

> +
> +	sd = &sensor->sd;
> +	v4l2_i2c_subdev_init(sd, client, &subdev_ops);
> +	sensor->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +
> +	sensor->pad.flags = MEDIA_PAD_FL_SOURCE;
> +	sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
> +	ret = media_entity_pads_init(&sd->entity, 1, &sensor->pad);
> +	if (ret < 0)
> +		goto mutex_remove;
> +
> +	ret = ov5647_detect(sd);
> +	if (ret < 0)
> +		goto error;
> +
> +	ret = v4l2_async_register_subdev(sd);
> +	if (ret < 0)
> +		goto error;
> +
> +	return 0;
> +error:
> +	media_entity_cleanup(&sd->entity);
> +mutex_remove:
> +	mutex_destroy(&sensor->lock);
> +	return ret;
> +}
> +
> +/**
> + * @short Exit routine - Exit point of the driver
> + * @param[in] client pointer to the i2c client structure
> + * @return 0 on success and a negative number on failure
> + */
> +static int ov5647_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ov5647 *ov5647 = to_state(sd);
> +
> +	v4l2_async_unregister_subdev(&ov5647->sd);
> +	media_entity_cleanup(&ov5647->sd.entity);
> +	v4l2_device_unregister_subdev(sd);
> +	mutex_destroy(&ov5647->lock);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id ov5647_id[] = {
> +	{ "ov5647", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, ov5647_id);
> +
> +#if IS_ENABLED(CONFIG_OF)

>From Kconfig the driver depends on OF.

> +static const struct of_device_id ov5647_of_match[] = {
> +	{ .compatible = "ovti,ov5647" },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, ov5647_of_match);
> +#endif
> +
> +/**
> + * @short i2c driver structure
> + */
> +static struct i2c_driver ov5647_driver = {
> +	.driver = {
> +		.of_match_table = of_match_ptr(ov5647_of_match),

Same comment as above, from Kconfig the driver depends on OF.

> +		.owner	= THIS_MODULE,

.owner is set by the core, please remove it.

> +		.name	= "ov5647",

May be .name = SENSOR_NAME, ?

Otherwise SENSOR_NAME macro is unused and it should be removed.

> +	},
> +	.probe		= ov5647_probe,
> +	.remove		= ov5647_remove,
> +	.id_table	= ov5647_id,
> +};
> +
> +module_i2c_driver(ov5647_driver);
> +
> +MODULE_AUTHOR("Ramiro Oliveira <roliveir@synopsys.com>");
> +MODULE_DESCRIPTION("A low-level driver for OmniVision ov5647 sensors");
> +MODULE_LICENSE("GPL v2");
> 

--
With best wishes,
Vladimir

Re: [PATCH v8 2/2] Add support for OV5647 sensor.

[Vladimir Zapolskiy]

Hello Ramiro,

On 02/13/2017 01:25 PM, Ramiro Oliveira wrote:
> Modes supported:
>  - 640x480 RAW 8
> 

It is a pretty short commit message, please consider to write a couple
of words about the sensor.

> Signed-off-by: Ramiro Oliveira <roliveir@synopsys.com>
> ---

[snip]

> +
> +struct cfg_array {
> +	struct regval_list *regs;
> +	int size;
> +};

struct cfg_array is apparently unused.

> +
> +/**
> + * @short I2C Write operation
> + * @param[in] i2c_client I2C client
> + * @param[in] reg register address
> + * @param[in] val value to write
> + * @return Error code
> + */
> +static int ov5647_write(struct v4l2_subdev *sd, u16 reg, u8 val)
> +{

The comment contents is probably outdated, because it does not describe
the function input arguments properly.

> +	int ret;
> +	unsigned char data[3] = { reg >> 8, reg & 0xff, val};
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ret = i2c_master_send(client, data, 3);
> +	if (ret != 3) {
> +		dev_dbg(&client->dev, "%s: i2c write error, reg: %x\n",
> +				__func__, reg);
> +		return ret < 0 ? ret : -EIO;

Here i2c_master_send() returns only to a negative error or '3', thus
the check is redundant.

Please do 'return ret';

> +	}
> +	return 0;
> +}
> +
> +/**
> + * @short I2C Read operation
> + * @param[in] i2c_client I2C client
> + * @param[in] reg register address
> + * @param[out] val value read
> + * @return Error code
> + */
> +static int ov5647_read(struct v4l2_subdev *sd, u16 reg, u8 *val)
> +{

Same as above, the comment must be updated.

> +	int ret;
> +	unsigned char data_w[2] = { reg >> 8, reg & 0xff };
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ret = i2c_master_send(client, data_w, 2);
> +
> +	if (ret < 2) {
> +		dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
> +			__func__, reg);
> +		return ret < 0 ? ret : -EIO;


Here i2c_master_send() returns only to a negative error or '2', thus
the check is redundant.

Please do 'return ret';

> +	}
> +
> +	ret = i2c_master_recv(client, val, 1);
> +
> +	if (ret < 1) {
> +		dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
> +				__func__, reg);
> +		return ret < 0 ? ret : -EIO;

Here i2c_master_recv() returns only to a negative error or '1', thus
the check is redundant.

Please do 'return ret';

> +	}
> +	return 0;
> +}
> +
> +static int ov5647_write_array(struct v4l2_subdev *sd,
> +				struct regval_list *regs, int array_size)
> +{
> +	int i = 0;
> +	int ret = 0;

Please don't assign a value to 'ret' and please do declarations on a single line.

> +
> +	if (!regs)
> +		return -EINVAL;

!regs is a dead code check, please remove it.

> +
> +	while (i < array_size) {
> +		ret = ov5647_write(sd, regs->addr, regs->data);
> +		if (ret < 0)
> +			return ret;
> +		i++;
> +		regs++;
> +	}

Please do a for-loop, it will save two lines of code:

	for (i = 0; i < array_size; i++) {
		ret = ov5647_write(sd, regs[i].addr, regs[i].data);
		if (ret < 0)
			return ret;
	}

> +	return 0;
> +}
> +
> +static int ov5647_set_virtual_channel(struct v4l2_subdev *sd, int channel)
> +{
> +	u8 channel_id;
> +	int ret = 0;

Please don't assign a value to 'ret' on declaration here.

> +
> +	ret = ov5647_read(sd, 0x4814, &channel_id);
> +	if (ret < 0)
> +		return ret;
> +
> +	channel_id &= ~(3 << 6);
> +	return ov5647_write(sd, 0x4814, channel_id | (channel << 6));
> +}
> +
> +static int ov5647_stream_on(struct v4l2_subdev *sd)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ov5647_write(sd, 0x4202, 0x00);
> +
> +	dev_dbg(&client->dev, "Stream on");
> +
> +	return ov5647_write(sd, 0x300D, 0x00);
> +}
> +
> +static int ov5647_stream_off(struct v4l2_subdev *sd)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ov5647_write(sd, 0x4202, 0x0f);
> +
> +	dev_dbg(&client->dev, "Stream off");
> +
> +	return ov5647_write(sd, 0x300D, 0x01);
> +}
> +
> +/**
> + * @short Set SW standby
> + * @param[in] sd v4l2 sd
> + * @param[in] stanby standby mode status (on or off)
> + * @return Error code
> + */
> +static int set_sw_standby(struct v4l2_subdev *sd, bool standby)
> +{
> +	int ret;
> +	unsigned char rdval;

ov5647_read() return value type is 'u8', please change it here and
everywhere else in the code.

> +
> +	ret = ov5647_read(sd, 0x0100, &rdval);
> +	if (ret != 0)

if (ret < 0)

> +		return ret;
> +
> +	if (standby)
> +		rdval &= 0xfe;

Here 'rdval &= ~0x01' would be preferred to emphasize symmetry.

> +	else
> +		rdval |= 0x01;
> +
> +	return ov5647_write(sd, 0x0100, rdval);
> +}
> +
> +/**
> + * @short Initialize sensor
> + * @param[in] sd v4l2 subdev
> + * @param[in] val not used
> + * @return Error code
> + */
> +static int __sensor_init(struct v4l2_subdev *sd)

Same as above, the comment must be updated.

> +{
> +	int ret;
> +	u8 resetval;
> +	u8 rdval;
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	dev_dbg(&client->dev, "sensor init\n");
> +
> +	ret = ov5647_read(sd, 0x0100, &rdval);
> +	if (ret != 0)

if (ret < 0)

> +		return ret;
> +
> +	ret = ov5647_write_array(sd, ov5647_640x480,
> +					ARRAY_SIZE(ov5647_640x480));
> +	if (ret < 0) {
> +		dev_err(&client->dev, "write sensor default regs error\n");
> +		return ret;
> +	}
> +
> +	ret = ov5647_set_virtual_channel(sd, 0);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ov5647_read(sd, 0x0100, &resetval);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (!(resetval & 0x01)) {
> +		dev_err(&client->dev, "Device was in SW standby");
> +		ret = ov5647_write(sd, 0x0100, 0x01);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return ov5647_write(sd, 0x4800, 0x04);
> +}
> +
> +/**
> + * @short Control sensor power state
> + * @param[in] sd v4l2 subdev
> + * @param[in] on Sensor power
> + * @return Error code
> + */
> +static int sensor_power(struct v4l2_subdev *sd, int on)
> +{
> +	int ret;
> +	struct ov5647 *ov5647 = to_state(sd);
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ret = 0;
> +	mutex_lock(&ov5647->lock);
> +
> +	if (on && !ov5647->power_count)	{
> +		dev_dbg(&client->dev, "OV5647 power on\n");
> +
> +		clk_set_rate(ov5647->xclk, ov5647->xclk_freq);
> +
> +		ret = clk_prepare_enable(ov5647->xclk);
> +		if (ret < 0) {
> +			dev_err(ov5647->dev, "clk prepare enable failed\n");
> +			goto out;
> +		}
> +
> +		ret = ov5647_write_array(sd, sensor_oe_enable_regs,
> +				ARRAY_SIZE(sensor_oe_enable_regs));
> +		if (ret < 0) {
> +			clk_disable_unprepare(ov5647->xclk);
> +			dev_err(&client->dev,
> +				"write sensor_oe_enable_regs error\n");
> +			goto out;
> +		}
> +
> +		ret = __sensor_init(sd);
> +		if (ret < 0) {
> +			clk_disable_unprepare(ov5647->xclk);
> +			dev_err(&client->dev,
> +				"Camera not available, check Power\n");
> +			goto out;
> +		}
> +	} else if (!on && ov5647->power_count == 1) {
> +		dev_dbg(&client->dev, "OV5647 power off\n");
> +
> +		dev_dbg(&client->dev, "disable oe\n");
> +		ret = ov5647_write_array(sd, sensor_oe_disable_regs,
> +				ARRAY_SIZE(sensor_oe_disable_regs));
> +
> +		if (ret < 0)
> +			dev_dbg(&client->dev, "disable oe failed\n");
> +
> +		ret = set_sw_standby(sd, true);
> +
> +		if (ret < 0)
> +			dev_dbg(&client->dev, "soft stby failed\n");
> +
> +		clk_disable_unprepare(ov5647->xclk);
> +	}
> +
> +	/* Update the power count. */
> +	ov5647->power_count += on ? 1 : -1;
> +	WARN_ON(ov5647->power_count < 0);
> +
> +out:
> +	mutex_unlock(&ov5647->lock);
> +
> +	return ret;
> +}
> +
> +#ifdef CONFIG_VIDEO_ADV_DEBUG
> +/**
> + * @short Get register value
> + * @param[in] sd v4l2 subdev
> + * @param[in] reg register struct
> + * @return Error code
> + */
> +static int sensor_get_register(struct v4l2_subdev *sd,
> +				struct v4l2_dbg_register *reg)
> +{
> +	unsigned char val = 0;

ov5647_read() return value type is 'u8', please change it here and
everywhere else in the code.

Also please don't assign a value to 'val' n declaration.

> +	int ret;
> +
> +	ret = ov5647_read(sd, reg->reg & 0xff, &val);
> +	if (ret != 0)

if (ret < 0)

> +		return ret;
> +
> +	reg->val = val;
> +	reg->size = 1;
> +
> +	return ret;

return 0;

> +}
> +
> +/**
> + * @short Set register value
> + * @param[in] sd v4l2 subdev
> + * @param[in] reg register struct
> + * @return Error code
> + */
> +static int sensor_set_register(struct v4l2_subdev *sd,
> +				const struct v4l2_dbg_register *reg)
> +{
> +	return ov5647_write(sd, reg->reg & 0xff, reg->val & 0xff);
> +}
> +#endif
> +
> +/**
> + * @short Subdev core operations registration
> + */
> +static const struct v4l2_subdev_core_ops subdev_core_ops = {
> +	.s_power		= sensor_power,
> +#ifdef CONFIG_VIDEO_ADV_DEBUG
> +	.g_register		= sensor_get_register,
> +	.s_register		= sensor_set_register,
> +#endif
> +};
> +
> +static int s_stream(struct v4l2_subdev *sd, int enable)
> +{
> +	if (!enable)
> +		return ov5647_stream_off(sd);
> +	else
> +		return ov5647_stream_on(sd);

To avoid a negation please do

	if (enable)
		return ov5647_stream_on(sd);
	else
		return ov5647_stream_off(sd);

> +}
> +
> +static const struct v4l2_subdev_video_ops subdev_video_ops = {
> +	.s_stream =		s_stream,
> +};
> +
> +

Please remove one of two empty lines in a row.

> +static int enum_mbus_code(struct v4l2_subdev *sd,
> +				struct v4l2_subdev_pad_config *cfg,
> +				struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	if (code->index > 0)
> +		return -EINVAL;
> +
> +	code->code = MEDIA_BUS_FMT_SBGGR8_1X8;
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_pad_ops subdev_pad_ops = {
> +	.enum_mbus_code =	enum_mbus_code,
> +};
> +
> +/**
> + * @short Subdev operations registration
> + *
> + */
> +static const struct v4l2_subdev_ops subdev_ops = {
> +	.core		= &subdev_core_ops,
> +	.video		= &subdev_video_ops,
> +	.pad		= &subdev_pad_ops,
> +};
> +
> +/**
> + * @short Detect camera version and model
> + * @param[in] sd v4l2 subdev
> + * @return Error code
> + */
> +static int ov5647_detect(struct v4l2_subdev *sd)
> +{
> +	unsigned char read;

ov5647_read() return value type is 'u8', please change it here and
everywhere else in the code.

> +	int ret;
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ret = ov5647_write(sd, OV5647_SW_RESET, 0x01);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ov5647_read(sd, OV5647_REG_CHIPID_H, &read);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (read != 0x56) {
> +		dev_err(&client->dev, "Wrong model version detected");
> +		return -ENODEV;
> +	}
> +
> +	ret = ov5647_read(sd, OV5647_REG_CHIPID_L, &read);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (read != 0x47) {
> +		dev_err(&client->dev, "Wrong model version detected");
> +		return -ENODEV;
> +	}
> +
> +	return ov5647_write(sd, OV5647_SW_RESET, 0x00);
> +}
> +
> +/**
> + * @short Detect if camera is registered
> + * @param[in] sd v4l2 subdev
> + * @return Error code
> + */
> +static int ov5647_registered(struct v4l2_subdev *sd)
> +{
> +	return 0;
> +}
> +
> +/**
> + * @short Open device
> + * @param[in] sd v4l2 subdev
> + * @param[in] fh v4l2 file handler
> + * @return Error code
> + */
> +static int ov5647_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	struct v4l2_mbus_framefmt *format =
> +				v4l2_subdev_get_try_format(sd, fh->pad, 0);
> +	struct v4l2_rect *crop =
> +				v4l2_subdev_get_try_crop(sd, fh->pad, 0);
> +
> +	crop->left = OV5647_COLUMN_START_DEF;
> +	crop->top = OV5647_ROW_START_DEF;
> +	crop->width = OV5647_WINDOW_WIDTH_DEF;
> +	crop->height = OV5647_WINDOW_HEIGHT_DEF;
> +
> +	format->code = MEDIA_BUS_FMT_SBGGR8_1X8;
> +
> +	format->width = OV5647_WINDOW_WIDTH_DEF;
> +	format->height = OV5647_WINDOW_HEIGHT_DEF;
> +	format->field = V4L2_FIELD_NONE;
> +	format->colorspace = V4L2_COLORSPACE_SRGB;
> +
> +	return sensor_power(sd, true);
> +}
> +
> +/**
> + * @short Open device
> + * @param[in] sd v4l2 subdev
> + * @param[in] fh v4l2 file handler
> + * @return Error code
> + */
> +static int ov5647_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	return sensor_power(sd, false);
> +}
> +
> +/**
> + * @short Subdev internal operations registration
> + *
> + */
> +static const struct v4l2_subdev_internal_ops ov5647_subdev_internal_ops = {
> +	.registered = ov5647_registered,
> +	.open = ov5647_open,
> +	.close = ov5647_close,
> +};
> +
> +/**
> + * @short Initialization routine - Entry point of the driver
> + * @param[in] client pointer to the i2c client structure
> + * @param[in] id pointer to the i2c device id structure
> + * @return 0 on success and a negative number on failure
> + */
> +static int ov5647_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	struct device *dev = &client->dev;
> +	struct ov5647 *sensor;
> +	int ret;
> +	struct v4l2_subdev *sd;
> +
> +	dev_info(&client->dev, "Installing OmniVision OV5647 camera driver\n");

Please remove the informational line, it will pollute the kernel log for no
good reason.

> +
> +	sensor = devm_kzalloc(dev, sizeof(*sensor), GFP_KERNEL);
> +	if (sensor == NULL)
> +		return -ENOMEM;
> +
> +	/* get system clock (xclk) */
> +	sensor->xclk = devm_clk_get(dev, "xclk");
> +	if (IS_ERR(sensor->xclk)) {
> +		dev_err(dev, "could not get xclk");
> +		return PTR_ERR(sensor->xclk);
> +	}
> +
> +	ret = of_property_read_u32(dev->of_node, "clock-frequency",
> +				    &sensor->xclk_freq);
> +	if (ret) {
> +		dev_err(dev, "could not get xclk frequency\n");
> +		return ret;
> +	}
> +
> +	mutex_init(&sensor->lock);
> +	sensor->dev = dev;

sensor->dev is unused, please remove it from the 'struct ov5647' declaration.

> +
> +	sd = &sensor->sd;
> +	v4l2_i2c_subdev_init(sd, client, &subdev_ops);
> +	sensor->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +
> +	sensor->pad.flags = MEDIA_PAD_FL_SOURCE;
> +	sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
> +	ret = media_entity_pads_init(&sd->entity, 1, &sensor->pad);
> +	if (ret < 0)
> +		goto mutex_remove;
> +
> +	ret = ov5647_detect(sd);
> +	if (ret < 0)
> +		goto error;
> +
> +	ret = v4l2_async_register_subdev(sd);
> +	if (ret < 0)
> +		goto error;
> +
> +	return 0;
> +error:
> +	media_entity_cleanup(&sd->entity);
> +mutex_remove:
> +	mutex_destroy(&sensor->lock);
> +	return ret;
> +}
> +
> +/**
> + * @short Exit routine - Exit point of the driver
> + * @param[in] client pointer to the i2c client structure
> + * @return 0 on success and a negative number on failure
> + */
> +static int ov5647_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ov5647 *ov5647 = to_state(sd);
> +
> +	v4l2_async_unregister_subdev(&ov5647->sd);
> +	media_entity_cleanup(&ov5647->sd.entity);
> +	v4l2_device_unregister_subdev(sd);
> +	mutex_destroy(&ov5647->lock);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id ov5647_id[] = {
> +	{ "ov5647", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, ov5647_id);
> +
> +#if IS_ENABLED(CONFIG_OF)

>From Kconfig the driver depends on OF.

> +static const struct of_device_id ov5647_of_match[] = {
> +	{ .compatible = "ovti,ov5647" },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, ov5647_of_match);
> +#endif
> +
> +/**
> + * @short i2c driver structure
> + */
> +static struct i2c_driver ov5647_driver = {
> +	.driver = {
> +		.of_match_table = of_match_ptr(ov5647_of_match),

Same comment as above, from Kconfig the driver depends on OF.

> +		.owner	= THIS_MODULE,

.owner is set by the core, please remove it.

> +		.name	= "ov5647",

May be .name = SENSOR_NAME, ?

Otherwise SENSOR_NAME macro is unused and it should be removed.

> +	},
> +	.probe		= ov5647_probe,
> +	.remove		= ov5647_remove,
> +	.id_table	= ov5647_id,
> +};
> +
> +module_i2c_driver(ov5647_driver);
> +
> +MODULE_AUTHOR("Ramiro Oliveira <roliveir@synopsys.com>");
> +MODULE_DESCRIPTION("A low-level driver for OmniVision ov5647 sensors");
> +MODULE_LICENSE("GPL v2");
> 

--
With best wishes,
Vladimir

Re: [PATCH v8 2/2] Add support for OV5647 sensor.

[Ramiro Oliveira]

Hi Vladimir,

Thank you for your feedback.

On 2/13/2017 12:21 PM, Vladimir Zapolskiy wrote:
> Hello Ramiro,
> 
> On 02/13/2017 01:25 PM, Ramiro Oliveira wrote:
>> Modes supported:
>>  - 640x480 RAW 8
>>
> 
> It is a pretty short commit message, please consider to write a couple
> of words about the sensor.
> 

Sure, I can do that.

>> Signed-off-by: Ramiro Oliveira <roliveir@synopsys.com>
>> ---
> 
> [snip]
> 
>> +
>> +struct cfg_array {
>> +	struct regval_list *regs;
>> +	int size;
>> +};
> 
> struct cfg_array is apparently unused.
> 

You're right. It's left-over code.

>> +
>> +/**
>> + * @short I2C Write operation
>> + * @param[in] i2c_client I2C client
>> + * @param[in] reg register address
>> + * @param[in] val value to write
>> + * @return Error code
>> + */
>> +static int ov5647_write(struct v4l2_subdev *sd, u16 reg, u8 val)
>> +{
> 
> The comment contents is probably outdated, because it does not describe
> the function input arguments properly.
> 

I'll remove the comments since the function is self-explanatory, I believe.

>> +	int ret;
>> +	unsigned char data[3] = { reg >> 8, reg & 0xff, val};
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ret = i2c_master_send(client, data, 3);
>> +	if (ret != 3) {
>> +		dev_dbg(&client->dev, "%s: i2c write error, reg: %x\n",
>> +				__func__, reg);
>> +		return ret < 0 ? ret : -EIO;
> 
> Here i2c_master_send() returns only to a negative error or '3', thus
> the check is redundant.
> 
> Please do 'return ret';
> 

I'll do that.

>> +	}
>> +	return 0;
>> +}
>> +
>> +/**
>> + * @short I2C Read operation
>> + * @param[in] i2c_client I2C client
>> + * @param[in] reg register address
>> + * @param[out] val value read
>> + * @return Error code
>> + */
>> +static int ov5647_read(struct v4l2_subdev *sd, u16 reg, u8 *val)
>> +{
> 
> Same as above, the comment must be updated.
> 

I'll remove the comments since the function is self-explanatory, I believe.

>> +	int ret;
>> +	unsigned char data_w[2] = { reg >> 8, reg & 0xff };
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ret = i2c_master_send(client, data_w, 2);
>> +
>> +	if (ret < 2) {
>> +		dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
>> +			__func__, reg);
>> +		return ret < 0 ? ret : -EIO;
> 
> 
> Here i2c_master_send() returns only to a negative error or '2', thus
> the check is redundant.
> 
> Please do 'return ret';
> 

I'll do that.

>> +	}
>> +
>> +	ret = i2c_master_recv(client, val, 1);
>> +
>> +	if (ret < 1) {
>> +		dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
>> +				__func__, reg);
>> +		return ret < 0 ? ret : -EIO;
> 
> Here i2c_master_recv() returns only to a negative error or '1', thus
> the check is redundant.
> 
> Please do 'return ret';
> 

I'll do that.

>> +	}
>> +	return 0;
>> +}
>> +
>> +static int ov5647_write_array(struct v4l2_subdev *sd,
>> +				struct regval_list *regs, int array_size)
>> +{
>> +	int i = 0;
>> +	int ret = 0;
> 
> Please don't assign a value to 'ret' and please do declarations on a single line.
> 

Ok.

>> +
>> +	if (!regs)
>> +		return -EINVAL;
> 
> !regs is a dead code check, please remove it.
> 

I'll do that.

>> +
>> +	while (i < array_size) {
>> +		ret = ov5647_write(sd, regs->addr, regs->data);
>> +		if (ret < 0)
>> +			return ret;
>> +		i++;
>> +		regs++;
>> +	}
> 
> Please do a for-loop, it will save two lines of code:
> 
> 	for (i = 0; i < array_size; i++) {
> 		ret = ov5647_write(sd, regs[i].addr, regs[i].data);
> 		if (ret < 0)
> 			return ret;
> 	}
> 

Sure, I can do that.

>> +	return 0;
>> +}
>> +
>> +static int ov5647_set_virtual_channel(struct v4l2_subdev *sd, int channel)
>> +{
>> +	u8 channel_id;
>> +	int ret = 0;
> 
> Please don't assign a value to 'ret' on declaration here.
> 

Ok.

>> +
>> +	ret = ov5647_read(sd, 0x4814, &channel_id);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	channel_id &= ~(3 << 6);
>> +	return ov5647_write(sd, 0x4814, channel_id | (channel << 6));
>> +}
>> +
>> +static int ov5647_stream_on(struct v4l2_subdev *sd)
>> +{
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ov5647_write(sd, 0x4202, 0x00);
>> +
>> +	dev_dbg(&client->dev, "Stream on");
>> +
>> +	return ov5647_write(sd, 0x300D, 0x00);
>> +}
>> +
>> +static int ov5647_stream_off(struct v4l2_subdev *sd)
>> +{
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ov5647_write(sd, 0x4202, 0x0f);
>> +
>> +	dev_dbg(&client->dev, "Stream off");
>> +
>> +	return ov5647_write(sd, 0x300D, 0x01);
>> +}
>> +
>> +/**
>> + * @short Set SW standby
>> + * @param[in] sd v4l2 sd
>> + * @param[in] stanby standby mode status (on or off)
>> + * @return Error code
>> + */
>> +static int set_sw_standby(struct v4l2_subdev *sd, bool standby)
>> +{
>> +	int ret;
>> +	unsigned char rdval;
> 
> ov5647_read() return value type is 'u8', please change it here and
> everywhere else in the code.
> 

Ok.

>> +
>> +	ret = ov5647_read(sd, 0x0100, &rdval);
>> +	if (ret != 0)
> 
> if (ret < 0)
> 

I'll change it.

>> +		return ret;
>> +
>> +	if (standby)
>> +		rdval &= 0xfe;
> 
> Here 'rdval &= ~0x01' would be preferred to emphasize symmetry.
> 

Sure, it makes sense.

>> +	else
>> +		rdval |= 0x01;
>> +
>> +	return ov5647_write(sd, 0x0100, rdval);
>> +}
>> +
>> +/**
>> + * @short Initialize sensor
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] val not used
>> + * @return Error code
>> + */
>> +static int __sensor_init(struct v4l2_subdev *sd)
> 
> Same as above, the comment must be updated.
> 

I'll remove the comments since the function is self-explanatory, I believe.

>> +{
>> +	int ret;
>> +	u8 resetval;
>> +	u8 rdval;
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	dev_dbg(&client->dev, "sensor init\n");
>> +
>> +	ret = ov5647_read(sd, 0x0100, &rdval);
>> +	if (ret != 0)
> 
> if (ret < 0)
> 

I'll change it.

>> +		return ret;
>> +
>> +	ret = ov5647_write_array(sd, ov5647_640x480,
>> +					ARRAY_SIZE(ov5647_640x480));
>> +	if (ret < 0) {
>> +		dev_err(&client->dev, "write sensor default regs error\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = ov5647_set_virtual_channel(sd, 0);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = ov5647_read(sd, 0x0100, &resetval);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (!(resetval & 0x01)) {
>> +		dev_err(&client->dev, "Device was in SW standby");
>> +		ret = ov5647_write(sd, 0x0100, 0x01);
>> +		if (ret < 0)
>> +			return ret;
>> +	}
>> +
>> +	return ov5647_write(sd, 0x4800, 0x04);
>> +}
>> +
>> +/**
>> + * @short Control sensor power state
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] on Sensor power
>> + * @return Error code
>> + */
>> +static int sensor_power(struct v4l2_subdev *sd, int on)
>> +{
>> +	int ret;
>> +	struct ov5647 *ov5647 = to_state(sd);
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ret = 0;
>> +	mutex_lock(&ov5647->lock);
>> +
>> +	if (on && !ov5647->power_count)	{
>> +		dev_dbg(&client->dev, "OV5647 power on\n");
>> +
>> +		clk_set_rate(ov5647->xclk, ov5647->xclk_freq);
>> +
>> +		ret = clk_prepare_enable(ov5647->xclk);
>> +		if (ret < 0) {
>> +			dev_err(ov5647->dev, "clk prepare enable failed\n");
>> +			goto out;
>> +		}
>> +
>> +		ret = ov5647_write_array(sd, sensor_oe_enable_regs,
>> +				ARRAY_SIZE(sensor_oe_enable_regs));
>> +		if (ret < 0) {
>> +			clk_disable_unprepare(ov5647->xclk);
>> +			dev_err(&client->dev,
>> +				"write sensor_oe_enable_regs error\n");
>> +			goto out;
>> +		}
>> +
>> +		ret = __sensor_init(sd);
>> +		if (ret < 0) {
>> +			clk_disable_unprepare(ov5647->xclk);
>> +			dev_err(&client->dev,
>> +				"Camera not available, check Power\n");
>> +			goto out;
>> +		}
>> +	} else if (!on && ov5647->power_count == 1) {
>> +		dev_dbg(&client->dev, "OV5647 power off\n");
>> +
>> +		dev_dbg(&client->dev, "disable oe\n");
>> +		ret = ov5647_write_array(sd, sensor_oe_disable_regs,
>> +				ARRAY_SIZE(sensor_oe_disable_regs));
>> +
>> +		if (ret < 0)
>> +			dev_dbg(&client->dev, "disable oe failed\n");
>> +
>> +		ret = set_sw_standby(sd, true);
>> +
>> +		if (ret < 0)
>> +			dev_dbg(&client->dev, "soft stby failed\n");
>> +
>> +		clk_disable_unprepare(ov5647->xclk);
>> +	}
>> +
>> +	/* Update the power count. */
>> +	ov5647->power_count += on ? 1 : -1;
>> +	WARN_ON(ov5647->power_count < 0);
>> +
>> +out:
>> +	mutex_unlock(&ov5647->lock);
>> +
>> +	return ret;
>> +}
>> +
>> +#ifdef CONFIG_VIDEO_ADV_DEBUG
>> +/**
>> + * @short Get register value
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] reg register struct
>> + * @return Error code
>> + */
>> +static int sensor_get_register(struct v4l2_subdev *sd,
>> +				struct v4l2_dbg_register *reg)
>> +{
>> +	unsigned char val = 0;
> 
> ov5647_read() return value type is 'u8', please change it here and
> everywhere else in the code.
> 
> Also please don't assign a value to 'val' n declaration.
> 

Ok.

>> +	int ret;
>> +
>> +	ret = ov5647_read(sd, reg->reg & 0xff, &val);
>> +	if (ret != 0)
> 
> if (ret < 0)
> 

I'll change it.

>> +		return ret;
>> +
>> +	reg->val = val;
>> +	reg->size = 1;
>> +
>> +	return ret;
> 
> return 0;
> 

Ok.

>> +}
>> +
>> +/**
>> + * @short Set register value
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] reg register struct
>> + * @return Error code
>> + */
>> +static int sensor_set_register(struct v4l2_subdev *sd,
>> +				const struct v4l2_dbg_register *reg)
>> +{
>> +	return ov5647_write(sd, reg->reg & 0xff, reg->val & 0xff);
>> +}
>> +#endif
>> +
>> +/**
>> + * @short Subdev core operations registration
>> + */
>> +static const struct v4l2_subdev_core_ops subdev_core_ops = {
>> +	.s_power		= sensor_power,
>> +#ifdef CONFIG_VIDEO_ADV_DEBUG
>> +	.g_register		= sensor_get_register,
>> +	.s_register		= sensor_set_register,
>> +#endif
>> +};
>> +
>> +static int s_stream(struct v4l2_subdev *sd, int enable)
>> +{
>> +	if (!enable)
>> +		return ov5647_stream_off(sd);
>> +	else
>> +		return ov5647_stream_on(sd);
> 
> To avoid a negation please do
> 
> 	if (enable)
> 		return ov5647_stream_on(sd);
> 	else
> 		return ov5647_stream_off(sd);
> 

No problem, I'll do that.

>> +}
>> +
>> +static const struct v4l2_subdev_video_ops subdev_video_ops = {
>> +	.s_stream =		s_stream,
>> +};
>> +
>> +
> 
> Please remove one of two empty lines in a row.
> 

Ok.

>> +static int enum_mbus_code(struct v4l2_subdev *sd,
>> +				struct v4l2_subdev_pad_config *cfg,
>> +				struct v4l2_subdev_mbus_code_enum *code)
>> +{
>> +	if (code->index > 0)
>> +		return -EINVAL;
>> +
>> +	code->code = MEDIA_BUS_FMT_SBGGR8_1X8;
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct v4l2_subdev_pad_ops subdev_pad_ops = {
>> +	.enum_mbus_code =	enum_mbus_code,
>> +};
>> +
>> +/**
>> + * @short Subdev operations registration
>> + *
>> + */
>> +static const struct v4l2_subdev_ops subdev_ops = {
>> +	.core		= &subdev_core_ops,
>> +	.video		= &subdev_video_ops,
>> +	.pad		= &subdev_pad_ops,
>> +};
>> +
>> +/**
>> + * @short Detect camera version and model
>> + * @param[in] sd v4l2 subdev
>> + * @return Error code
>> + */
>> +static int ov5647_detect(struct v4l2_subdev *sd)
>> +{
>> +	unsigned char read;
> 
> ov5647_read() return value type is 'u8', please change it here and
> everywhere else in the code.
> 

OK.

>> +	int ret;
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ret = ov5647_write(sd, OV5647_SW_RESET, 0x01);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = ov5647_read(sd, OV5647_REG_CHIPID_H, &read);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (read != 0x56) {
>> +		dev_err(&client->dev, "Wrong model version detected");
>> +		return -ENODEV;
>> +	}
>> +
>> +	ret = ov5647_read(sd, OV5647_REG_CHIPID_L, &read);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (read != 0x47) {
>> +		dev_err(&client->dev, "Wrong model version detected");
>> +		return -ENODEV;
>> +	}
>> +
>> +	return ov5647_write(sd, OV5647_SW_RESET, 0x00);
>> +}
>> +
>> +/**
>> + * @short Detect if camera is registered
>> + * @param[in] sd v4l2 subdev
>> + * @return Error code
>> + */
>> +static int ov5647_registered(struct v4l2_subdev *sd)
>> +{
>> +	return 0;
>> +}
>> +
>> +/**
>> + * @short Open device
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] fh v4l2 file handler
>> + * @return Error code
>> + */
>> +static int ov5647_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
>> +{
>> +	struct v4l2_mbus_framefmt *format =
>> +				v4l2_subdev_get_try_format(sd, fh->pad, 0);
>> +	struct v4l2_rect *crop =
>> +				v4l2_subdev_get_try_crop(sd, fh->pad, 0);
>> +
>> +	crop->left = OV5647_COLUMN_START_DEF;
>> +	crop->top = OV5647_ROW_START_DEF;
>> +	crop->width = OV5647_WINDOW_WIDTH_DEF;
>> +	crop->height = OV5647_WINDOW_HEIGHT_DEF;
>> +
>> +	format->code = MEDIA_BUS_FMT_SBGGR8_1X8;
>> +
>> +	format->width = OV5647_WINDOW_WIDTH_DEF;
>> +	format->height = OV5647_WINDOW_HEIGHT_DEF;
>> +	format->field = V4L2_FIELD_NONE;
>> +	format->colorspace = V4L2_COLORSPACE_SRGB;
>> +
>> +	return sensor_power(sd, true);
>> +}
>> +
>> +/**
>> + * @short Open device
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] fh v4l2 file handler
>> + * @return Error code
>> + */
>> +static int ov5647_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
>> +{
>> +	return sensor_power(sd, false);
>> +}
>> +
>> +/**
>> + * @short Subdev internal operations registration
>> + *
>> + */
>> +static const struct v4l2_subdev_internal_ops ov5647_subdev_internal_ops = {
>> +	.registered = ov5647_registered,
>> +	.open = ov5647_open,
>> +	.close = ov5647_close,
>> +};
>> +
>> +/**
>> + * @short Initialization routine - Entry point of the driver
>> + * @param[in] client pointer to the i2c client structure
>> + * @param[in] id pointer to the i2c device id structure
>> + * @return 0 on success and a negative number on failure
>> + */
>> +static int ov5647_probe(struct i2c_client *client,
>> +			const struct i2c_device_id *id)
>> +{
>> +	struct device *dev = &client->dev;
>> +	struct ov5647 *sensor;
>> +	int ret;
>> +	struct v4l2_subdev *sd;
>> +
>> +	dev_info(&client->dev, "Installing OmniVision OV5647 camera driver\n");
> 
> Please remove the informational line, it will pollute the kernel log for no
> good reason.
> 

Is it okay if I change it to debug?

>> +
>> +	sensor = devm_kzalloc(dev, sizeof(*sensor), GFP_KERNEL);
>> +	if (sensor == NULL)
>> +		return -ENOMEM;
>> +
>> +	/* get system clock (xclk) */
>> +	sensor->xclk = devm_clk_get(dev, "xclk");
>> +	if (IS_ERR(sensor->xclk)) {
>> +		dev_err(dev, "could not get xclk");
>> +		return PTR_ERR(sensor->xclk);
>> +	}
>> +
>> +	ret = of_property_read_u32(dev->of_node, "clock-frequency",
>> +				    &sensor->xclk_freq);
>> +	if (ret) {
>> +		dev_err(dev, "could not get xclk frequency\n");
>> +		return ret;
>> +	}
>> +
>> +	mutex_init(&sensor->lock);
>> +	sensor->dev = dev;
> 
> sensor->dev is unused, please remove it from the 'struct ov5647' declaration.
> 

Ok.

>> +
>> +	sd = &sensor->sd;
>> +	v4l2_i2c_subdev_init(sd, client, &subdev_ops);
>> +	sensor->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
>> +
>> +	sensor->pad.flags = MEDIA_PAD_FL_SOURCE;
>> +	sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
>> +	ret = media_entity_pads_init(&sd->entity, 1, &sensor->pad);
>> +	if (ret < 0)
>> +		goto mutex_remove;
>> +
>> +	ret = ov5647_detect(sd);
>> +	if (ret < 0)
>> +		goto error;
>> +
>> +	ret = v4l2_async_register_subdev(sd);
>> +	if (ret < 0)
>> +		goto error;
>> +
>> +	return 0;
>> +error:
>> +	media_entity_cleanup(&sd->entity);
>> +mutex_remove:
>> +	mutex_destroy(&sensor->lock);
>> +	return ret;
>> +}
>> +
>> +/**
>> + * @short Exit routine - Exit point of the driver
>> + * @param[in] client pointer to the i2c client structure
>> + * @return 0 on success and a negative number on failure
>> + */
>> +static int ov5647_remove(struct i2c_client *client)
>> +{
>> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
>> +	struct ov5647 *ov5647 = to_state(sd);
>> +
>> +	v4l2_async_unregister_subdev(&ov5647->sd);
>> +	media_entity_cleanup(&ov5647->sd.entity);
>> +	v4l2_device_unregister_subdev(sd);
>> +	mutex_destroy(&ov5647->lock);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct i2c_device_id ov5647_id[] = {
>> +	{ "ov5647", 0 },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(i2c, ov5647_id);
>> +
>> +#if IS_ENABLED(CONFIG_OF)
> 
> From Kconfig the driver depends on OF.
> 

You're right. Do you think I should remove the dependency in Kconfig or the
check here?

>> +static const struct of_device_id ov5647_of_match[] = {
>> +	{ .compatible = "ovti,ov5647" },
>> +	{ /* sentinel */ },
>> +};
>> +MODULE_DEVICE_TABLE(of, ov5647_of_match);
>> +#endif
>> +
>> +/**
>> + * @short i2c driver structure
>> + */
>> +static struct i2c_driver ov5647_driver = {
>> +	.driver = {
>> +		.of_match_table = of_match_ptr(ov5647_of_match),
> 
> Same comment as above, from Kconfig the driver depends on OF.
> 

I'm sorry but I'm not understanding what you're trying to say.

>> +		.owner	= THIS_MODULE,
> 
> .owner is set by the core, please remove it.
> 

Ok.

>> +		.name	= "ov5647",
> 
> May be .name = SENSOR_NAME, ?
> 
> Otherwise SENSOR_NAME macro is unused and it should be removed.
> 

I'll change it to .name = SENSOR_NAME,

>> +	},
>> +	.probe		= ov5647_probe,
>> +	.remove		= ov5647_remove,
>> +	.id_table	= ov5647_id,
>> +};
>> +
>> +module_i2c_driver(ov5647_driver);
>> +
>> +MODULE_AUTHOR("Ramiro Oliveira <roliveir@synopsys.com>");
>> +MODULE_DESCRIPTION("A low-level driver for OmniVision ov5647 sensors");
>> +MODULE_LICENSE("GPL v2");
>>
> 
> --
> With best wishes,
> Vladimir
> 

-- 
Best Regards

Ramiro Oliveira
Ramiro.Oliveira@synopsys.com

Re: [PATCH v8 2/2] Add support for OV5647 sensor.

[Ramiro Oliveira]

Hi Vladimir,

Thank you for your feedback.

On 2/13/2017 12:21 PM, Vladimir Zapolskiy wrote:
> Hello Ramiro,
> 
> On 02/13/2017 01:25 PM, Ramiro Oliveira wrote:
>> Modes supported:
>>  - 640x480 RAW 8
>>
> 
> It is a pretty short commit message, please consider to write a couple
> of words about the sensor.
> 

Sure, I can do that.

>> Signed-off-by: Ramiro Oliveira <roliveir-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>
>> ---
> 
> [snip]
> 
>> +
>> +struct cfg_array {
>> +	struct regval_list *regs;
>> +	int size;
>> +};
> 
> struct cfg_array is apparently unused.
> 

You're right. It's left-over code.

>> +
>> +/**
>> + * @short I2C Write operation
>> + * @param[in] i2c_client I2C client
>> + * @param[in] reg register address
>> + * @param[in] val value to write
>> + * @return Error code
>> + */
>> +static int ov5647_write(struct v4l2_subdev *sd, u16 reg, u8 val)
>> +{
> 
> The comment contents is probably outdated, because it does not describe
> the function input arguments properly.
> 

I'll remove the comments since the function is self-explanatory, I believe.

>> +	int ret;
>> +	unsigned char data[3] = { reg >> 8, reg & 0xff, val};
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ret = i2c_master_send(client, data, 3);
>> +	if (ret != 3) {
>> +		dev_dbg(&client->dev, "%s: i2c write error, reg: %x\n",
>> +				__func__, reg);
>> +		return ret < 0 ? ret : -EIO;
> 
> Here i2c_master_send() returns only to a negative error or '3', thus
> the check is redundant.
> 
> Please do 'return ret';
> 

I'll do that.

>> +	}
>> +	return 0;
>> +}
>> +
>> +/**
>> + * @short I2C Read operation
>> + * @param[in] i2c_client I2C client
>> + * @param[in] reg register address
>> + * @param[out] val value read
>> + * @return Error code
>> + */
>> +static int ov5647_read(struct v4l2_subdev *sd, u16 reg, u8 *val)
>> +{
> 
> Same as above, the comment must be updated.
> 

I'll remove the comments since the function is self-explanatory, I believe.

>> +	int ret;
>> +	unsigned char data_w[2] = { reg >> 8, reg & 0xff };
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ret = i2c_master_send(client, data_w, 2);
>> +
>> +	if (ret < 2) {
>> +		dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
>> +			__func__, reg);
>> +		return ret < 0 ? ret : -EIO;
> 
> 
> Here i2c_master_send() returns only to a negative error or '2', thus
> the check is redundant.
> 
> Please do 'return ret';
> 

I'll do that.

>> +	}
>> +
>> +	ret = i2c_master_recv(client, val, 1);
>> +
>> +	if (ret < 1) {
>> +		dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
>> +				__func__, reg);
>> +		return ret < 0 ? ret : -EIO;
> 
> Here i2c_master_recv() returns only to a negative error or '1', thus
> the check is redundant.
> 
> Please do 'return ret';
> 

I'll do that.

>> +	}
>> +	return 0;
>> +}
>> +
>> +static int ov5647_write_array(struct v4l2_subdev *sd,
>> +				struct regval_list *regs, int array_size)
>> +{
>> +	int i = 0;
>> +	int ret = 0;
> 
> Please don't assign a value to 'ret' and please do declarations on a single line.
> 

Ok.

>> +
>> +	if (!regs)
>> +		return -EINVAL;
> 
> !regs is a dead code check, please remove it.
> 

I'll do that.

>> +
>> +	while (i < array_size) {
>> +		ret = ov5647_write(sd, regs->addr, regs->data);
>> +		if (ret < 0)
>> +			return ret;
>> +		i++;
>> +		regs++;
>> +	}
> 
> Please do a for-loop, it will save two lines of code:
> 
> 	for (i = 0; i < array_size; i++) {
> 		ret = ov5647_write(sd, regs[i].addr, regs[i].data);
> 		if (ret < 0)
> 			return ret;
> 	}
> 

Sure, I can do that.

>> +	return 0;
>> +}
>> +
>> +static int ov5647_set_virtual_channel(struct v4l2_subdev *sd, int channel)
>> +{
>> +	u8 channel_id;
>> +	int ret = 0;
> 
> Please don't assign a value to 'ret' on declaration here.
> 

Ok.

>> +
>> +	ret = ov5647_read(sd, 0x4814, &channel_id);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	channel_id &= ~(3 << 6);
>> +	return ov5647_write(sd, 0x4814, channel_id | (channel << 6));
>> +}
>> +
>> +static int ov5647_stream_on(struct v4l2_subdev *sd)
>> +{
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ov5647_write(sd, 0x4202, 0x00);
>> +
>> +	dev_dbg(&client->dev, "Stream on");
>> +
>> +	return ov5647_write(sd, 0x300D, 0x00);
>> +}
>> +
>> +static int ov5647_stream_off(struct v4l2_subdev *sd)
>> +{
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ov5647_write(sd, 0x4202, 0x0f);
>> +
>> +	dev_dbg(&client->dev, "Stream off");
>> +
>> +	return ov5647_write(sd, 0x300D, 0x01);
>> +}
>> +
>> +/**
>> + * @short Set SW standby
>> + * @param[in] sd v4l2 sd
>> + * @param[in] stanby standby mode status (on or off)
>> + * @return Error code
>> + */
>> +static int set_sw_standby(struct v4l2_subdev *sd, bool standby)
>> +{
>> +	int ret;
>> +	unsigned char rdval;
> 
> ov5647_read() return value type is 'u8', please change it here and
> everywhere else in the code.
> 

Ok.

>> +
>> +	ret = ov5647_read(sd, 0x0100, &rdval);
>> +	if (ret != 0)
> 
> if (ret < 0)
> 

I'll change it.

>> +		return ret;
>> +
>> +	if (standby)
>> +		rdval &= 0xfe;
> 
> Here 'rdval &= ~0x01' would be preferred to emphasize symmetry.
> 

Sure, it makes sense.

>> +	else
>> +		rdval |= 0x01;
>> +
>> +	return ov5647_write(sd, 0x0100, rdval);
>> +}
>> +
>> +/**
>> + * @short Initialize sensor
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] val not used
>> + * @return Error code
>> + */
>> +static int __sensor_init(struct v4l2_subdev *sd)
> 
> Same as above, the comment must be updated.
> 

I'll remove the comments since the function is self-explanatory, I believe.

>> +{
>> +	int ret;
>> +	u8 resetval;
>> +	u8 rdval;
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	dev_dbg(&client->dev, "sensor init\n");
>> +
>> +	ret = ov5647_read(sd, 0x0100, &rdval);
>> +	if (ret != 0)
> 
> if (ret < 0)
> 

I'll change it.

>> +		return ret;
>> +
>> +	ret = ov5647_write_array(sd, ov5647_640x480,
>> +					ARRAY_SIZE(ov5647_640x480));
>> +	if (ret < 0) {
>> +		dev_err(&client->dev, "write sensor default regs error\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = ov5647_set_virtual_channel(sd, 0);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = ov5647_read(sd, 0x0100, &resetval);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (!(resetval & 0x01)) {
>> +		dev_err(&client->dev, "Device was in SW standby");
>> +		ret = ov5647_write(sd, 0x0100, 0x01);
>> +		if (ret < 0)
>> +			return ret;
>> +	}
>> +
>> +	return ov5647_write(sd, 0x4800, 0x04);
>> +}
>> +
>> +/**
>> + * @short Control sensor power state
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] on Sensor power
>> + * @return Error code
>> + */
>> +static int sensor_power(struct v4l2_subdev *sd, int on)
>> +{
>> +	int ret;
>> +	struct ov5647 *ov5647 = to_state(sd);
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ret = 0;
>> +	mutex_lock(&ov5647->lock);
>> +
>> +	if (on && !ov5647->power_count)	{
>> +		dev_dbg(&client->dev, "OV5647 power on\n");
>> +
>> +		clk_set_rate(ov5647->xclk, ov5647->xclk_freq);
>> +
>> +		ret = clk_prepare_enable(ov5647->xclk);
>> +		if (ret < 0) {
>> +			dev_err(ov5647->dev, "clk prepare enable failed\n");
>> +			goto out;
>> +		}
>> +
>> +		ret = ov5647_write_array(sd, sensor_oe_enable_regs,
>> +				ARRAY_SIZE(sensor_oe_enable_regs));
>> +		if (ret < 0) {
>> +			clk_disable_unprepare(ov5647->xclk);
>> +			dev_err(&client->dev,
>> +				"write sensor_oe_enable_regs error\n");
>> +			goto out;
>> +		}
>> +
>> +		ret = __sensor_init(sd);
>> +		if (ret < 0) {
>> +			clk_disable_unprepare(ov5647->xclk);
>> +			dev_err(&client->dev,
>> +				"Camera not available, check Power\n");
>> +			goto out;
>> +		}
>> +	} else if (!on && ov5647->power_count == 1) {
>> +		dev_dbg(&client->dev, "OV5647 power off\n");
>> +
>> +		dev_dbg(&client->dev, "disable oe\n");
>> +		ret = ov5647_write_array(sd, sensor_oe_disable_regs,
>> +				ARRAY_SIZE(sensor_oe_disable_regs));
>> +
>> +		if (ret < 0)
>> +			dev_dbg(&client->dev, "disable oe failed\n");
>> +
>> +		ret = set_sw_standby(sd, true);
>> +
>> +		if (ret < 0)
>> +			dev_dbg(&client->dev, "soft stby failed\n");
>> +
>> +		clk_disable_unprepare(ov5647->xclk);
>> +	}
>> +
>> +	/* Update the power count. */
>> +	ov5647->power_count += on ? 1 : -1;
>> +	WARN_ON(ov5647->power_count < 0);
>> +
>> +out:
>> +	mutex_unlock(&ov5647->lock);
>> +
>> +	return ret;
>> +}
>> +
>> +#ifdef CONFIG_VIDEO_ADV_DEBUG
>> +/**
>> + * @short Get register value
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] reg register struct
>> + * @return Error code
>> + */
>> +static int sensor_get_register(struct v4l2_subdev *sd,
>> +				struct v4l2_dbg_register *reg)
>> +{
>> +	unsigned char val = 0;
> 
> ov5647_read() return value type is 'u8', please change it here and
> everywhere else in the code.
> 
> Also please don't assign a value to 'val' n declaration.
> 

Ok.

>> +	int ret;
>> +
>> +	ret = ov5647_read(sd, reg->reg & 0xff, &val);
>> +	if (ret != 0)
> 
> if (ret < 0)
> 

I'll change it.

>> +		return ret;
>> +
>> +	reg->val = val;
>> +	reg->size = 1;
>> +
>> +	return ret;
> 
> return 0;
> 

Ok.

>> +}
>> +
>> +/**
>> + * @short Set register value
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] reg register struct
>> + * @return Error code
>> + */
>> +static int sensor_set_register(struct v4l2_subdev *sd,
>> +				const struct v4l2_dbg_register *reg)
>> +{
>> +	return ov5647_write(sd, reg->reg & 0xff, reg->val & 0xff);
>> +}
>> +#endif
>> +
>> +/**
>> + * @short Subdev core operations registration
>> + */
>> +static const struct v4l2_subdev_core_ops subdev_core_ops = {
>> +	.s_power		= sensor_power,
>> +#ifdef CONFIG_VIDEO_ADV_DEBUG
>> +	.g_register		= sensor_get_register,
>> +	.s_register		= sensor_set_register,
>> +#endif
>> +};
>> +
>> +static int s_stream(struct v4l2_subdev *sd, int enable)
>> +{
>> +	if (!enable)
>> +		return ov5647_stream_off(sd);
>> +	else
>> +		return ov5647_stream_on(sd);
> 
> To avoid a negation please do
> 
> 	if (enable)
> 		return ov5647_stream_on(sd);
> 	else
> 		return ov5647_stream_off(sd);
> 

No problem, I'll do that.

>> +}
>> +
>> +static const struct v4l2_subdev_video_ops subdev_video_ops = {
>> +	.s_stream =		s_stream,
>> +};
>> +
>> +
> 
> Please remove one of two empty lines in a row.
> 

Ok.

>> +static int enum_mbus_code(struct v4l2_subdev *sd,
>> +				struct v4l2_subdev_pad_config *cfg,
>> +				struct v4l2_subdev_mbus_code_enum *code)
>> +{
>> +	if (code->index > 0)
>> +		return -EINVAL;
>> +
>> +	code->code = MEDIA_BUS_FMT_SBGGR8_1X8;
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct v4l2_subdev_pad_ops subdev_pad_ops = {
>> +	.enum_mbus_code =	enum_mbus_code,
>> +};
>> +
>> +/**
>> + * @short Subdev operations registration
>> + *
>> + */
>> +static const struct v4l2_subdev_ops subdev_ops = {
>> +	.core		= &subdev_core_ops,
>> +	.video		= &subdev_video_ops,
>> +	.pad		= &subdev_pad_ops,
>> +};
>> +
>> +/**
>> + * @short Detect camera version and model
>> + * @param[in] sd v4l2 subdev
>> + * @return Error code
>> + */
>> +static int ov5647_detect(struct v4l2_subdev *sd)
>> +{
>> +	unsigned char read;
> 
> ov5647_read() return value type is 'u8', please change it here and
> everywhere else in the code.
> 

OK.

>> +	int ret;
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +
>> +	ret = ov5647_write(sd, OV5647_SW_RESET, 0x01);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = ov5647_read(sd, OV5647_REG_CHIPID_H, &read);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (read != 0x56) {
>> +		dev_err(&client->dev, "Wrong model version detected");
>> +		return -ENODEV;
>> +	}
>> +
>> +	ret = ov5647_read(sd, OV5647_REG_CHIPID_L, &read);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (read != 0x47) {
>> +		dev_err(&client->dev, "Wrong model version detected");
>> +		return -ENODEV;
>> +	}
>> +
>> +	return ov5647_write(sd, OV5647_SW_RESET, 0x00);
>> +}
>> +
>> +/**
>> + * @short Detect if camera is registered
>> + * @param[in] sd v4l2 subdev
>> + * @return Error code
>> + */
>> +static int ov5647_registered(struct v4l2_subdev *sd)
>> +{
>> +	return 0;
>> +}
>> +
>> +/**
>> + * @short Open device
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] fh v4l2 file handler
>> + * @return Error code
>> + */
>> +static int ov5647_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
>> +{
>> +	struct v4l2_mbus_framefmt *format =
>> +				v4l2_subdev_get_try_format(sd, fh->pad, 0);
>> +	struct v4l2_rect *crop =
>> +				v4l2_subdev_get_try_crop(sd, fh->pad, 0);
>> +
>> +	crop->left = OV5647_COLUMN_START_DEF;
>> +	crop->top = OV5647_ROW_START_DEF;
>> +	crop->width = OV5647_WINDOW_WIDTH_DEF;
>> +	crop->height = OV5647_WINDOW_HEIGHT_DEF;
>> +
>> +	format->code = MEDIA_BUS_FMT_SBGGR8_1X8;
>> +
>> +	format->width = OV5647_WINDOW_WIDTH_DEF;
>> +	format->height = OV5647_WINDOW_HEIGHT_DEF;
>> +	format->field = V4L2_FIELD_NONE;
>> +	format->colorspace = V4L2_COLORSPACE_SRGB;
>> +
>> +	return sensor_power(sd, true);
>> +}
>> +
>> +/**
>> + * @short Open device
>> + * @param[in] sd v4l2 subdev
>> + * @param[in] fh v4l2 file handler
>> + * @return Error code
>> + */
>> +static int ov5647_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
>> +{
>> +	return sensor_power(sd, false);
>> +}
>> +
>> +/**
>> + * @short Subdev internal operations registration
>> + *
>> + */
>> +static const struct v4l2_subdev_internal_ops ov5647_subdev_internal_ops = {
>> +	.registered = ov5647_registered,
>> +	.open = ov5647_open,
>> +	.close = ov5647_close,
>> +};
>> +
>> +/**
>> + * @short Initialization routine - Entry point of the driver
>> + * @param[in] client pointer to the i2c client structure
>> + * @param[in] id pointer to the i2c device id structure
>> + * @return 0 on success and a negative number on failure
>> + */
>> +static int ov5647_probe(struct i2c_client *client,
>> +			const struct i2c_device_id *id)
>> +{
>> +	struct device *dev = &client->dev;
>> +	struct ov5647 *sensor;
>> +	int ret;
>> +	struct v4l2_subdev *sd;
>> +
>> +	dev_info(&client->dev, "Installing OmniVision OV5647 camera driver\n");
> 
> Please remove the informational line, it will pollute the kernel log for no
> good reason.
> 

Is it okay if I change it to debug?

>> +
>> +	sensor = devm_kzalloc(dev, sizeof(*sensor), GFP_KERNEL);
>> +	if (sensor == NULL)
>> +		return -ENOMEM;
>> +
>> +	/* get system clock (xclk) */
>> +	sensor->xclk = devm_clk_get(dev, "xclk");
>> +	if (IS_ERR(sensor->xclk)) {
>> +		dev_err(dev, "could not get xclk");
>> +		return PTR_ERR(sensor->xclk);
>> +	}
>> +
>> +	ret = of_property_read_u32(dev->of_node, "clock-frequency",
>> +				    &sensor->xclk_freq);
>> +	if (ret) {
>> +		dev_err(dev, "could not get xclk frequency\n");
>> +		return ret;
>> +	}
>> +
>> +	mutex_init(&sensor->lock);
>> +	sensor->dev = dev;
> 
> sensor->dev is unused, please remove it from the 'struct ov5647' declaration.
> 

Ok.

>> +
>> +	sd = &sensor->sd;
>> +	v4l2_i2c_subdev_init(sd, client, &subdev_ops);
>> +	sensor->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
>> +
>> +	sensor->pad.flags = MEDIA_PAD_FL_SOURCE;
>> +	sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
>> +	ret = media_entity_pads_init(&sd->entity, 1, &sensor->pad);
>> +	if (ret < 0)
>> +		goto mutex_remove;
>> +
>> +	ret = ov5647_detect(sd);
>> +	if (ret < 0)
>> +		goto error;
>> +
>> +	ret = v4l2_async_register_subdev(sd);
>> +	if (ret < 0)
>> +		goto error;
>> +
>> +	return 0;
>> +error:
>> +	media_entity_cleanup(&sd->entity);
>> +mutex_remove:
>> +	mutex_destroy(&sensor->lock);
>> +	return ret;
>> +}
>> +
>> +/**
>> + * @short Exit routine - Exit point of the driver
>> + * @param[in] client pointer to the i2c client structure
>> + * @return 0 on success and a negative number on failure
>> + */
>> +static int ov5647_remove(struct i2c_client *client)
>> +{
>> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
>> +	struct ov5647 *ov5647 = to_state(sd);
>> +
>> +	v4l2_async_unregister_subdev(&ov5647->sd);
>> +	media_entity_cleanup(&ov5647->sd.entity);
>> +	v4l2_device_unregister_subdev(sd);
>> +	mutex_destroy(&ov5647->lock);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct i2c_device_id ov5647_id[] = {
>> +	{ "ov5647", 0 },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(i2c, ov5647_id);
>> +
>> +#if IS_ENABLED(CONFIG_OF)
> 
> From Kconfig the driver depends on OF.
> 

You're right. Do you think I should remove the dependency in Kconfig or the
check here?

>> +static const struct of_device_id ov5647_of_match[] = {
>> +	{ .compatible = "ovti,ov5647" },
>> +	{ /* sentinel */ },
>> +};
>> +MODULE_DEVICE_TABLE(of, ov5647_of_match);
>> +#endif
>> +
>> +/**
>> + * @short i2c driver structure
>> + */
>> +static struct i2c_driver ov5647_driver = {
>> +	.driver = {
>> +		.of_match_table = of_match_ptr(ov5647_of_match),
> 
> Same comment as above, from Kconfig the driver depends on OF.
> 

I'm sorry but I'm not understanding what you're trying to say.

>> +		.owner	= THIS_MODULE,
> 
> .owner is set by the core, please remove it.
> 

Ok.

>> +		.name	= "ov5647",
> 
> May be .name = SENSOR_NAME, ?
> 
> Otherwise SENSOR_NAME macro is unused and it should be removed.
> 

I'll change it to .name = SENSOR_NAME,

>> +	},
>> +	.probe		= ov5647_probe,
>> +	.remove		= ov5647_remove,
>> +	.id_table	= ov5647_id,
>> +};
>> +
>> +module_i2c_driver(ov5647_driver);
>> +
>> +MODULE_AUTHOR("Ramiro Oliveira <roliveir-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>");
>> +MODULE_DESCRIPTION("A low-level driver for OmniVision ov5647 sensors");
>> +MODULE_LICENSE("GPL v2");
>>
> 
> --
> With best wishes,
> Vladimir
> 

-- 
Best Regards

Ramiro Oliveira
Ramiro.Oliveira-HKixBCOQz3hWk0Htik3J/w@public.gmane.org
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Re: [PATCH v8 2/2] Add support for OV5647 sensor.

[Vladimir Zapolskiy]

Hi Ramiro,

On 02/13/2017 09:14 PM, Ramiro Oliveira wrote:
> Hi Vladimir,
> 
> Thank you for your feedback.
> 
> On 2/13/2017 12:21 PM, Vladimir Zapolskiy wrote:
>> Hello Ramiro,
>>
>> On 02/13/2017 01:25 PM, Ramiro Oliveira wrote:
>>> Modes supported:
>>>  - 640x480 RAW 8
>>>

[snip]

>>> +static int ov5647_probe(struct i2c_client *client,
>>> +			const struct i2c_device_id *id)
>>> +{
>>> +	struct device *dev = &client->dev;
>>> +	struct ov5647 *sensor;
>>> +	int ret;
>>> +	struct v4l2_subdev *sd;
>>> +
>>> +	dev_info(&client->dev, "Installing OmniVision OV5647 camera driver\n");
>>
>> Please remove the informational line, it will pollute the kernel log for no
>> good reason.
>>
> 
> Is it okay if I change it to debug?
> 

Most probably here it is okay to change it to dev_dbg(), however

1) please note that ftrace functionality should provide all the magic for you,
   and by the way this makes dev_dbg() calls from ov5647_write(), ov5647_read(),
   ov5647_stream_on(), ov5647_stream_off() and __sensor_init() all redundant,

2) please move the informational message to the end of the .probe function,
   right before returning success to avoid duplicates on deferred re-probing:

	dev_dbg(&client->dev, "OmniVision OV5647 camera driver probed\n");
	                                                      ^^^^^^^^
[snip]

>>> +
>>> +static const struct i2c_device_id ov5647_id[] = {
>>> +	{ "ov5647", 0 },
>>> +	{ }
>>> +};
>>> +MODULE_DEVICE_TABLE(i2c, ov5647_id);
>>> +
>>> +#if IS_ENABLED(CONFIG_OF)
>>
>> From Kconfig the driver depends on OF.
>>
> 
> You're right. Do you think I should remove the dependency in Kconfig or the
> check here?
> 

Let see...

I've been able to locate only one place where OF dependency is utterly needed:

	ret = of_property_read_u32(dev->of_node, "clock-frequency",
				    &sensor->xclk_freq);
	if (ret) {
		dev_err(dev, "could not get xclk frequency\n");
		return ret;
	}

It might be preferred to change this snippet of code into something like one
below:

	sensor->xclk_freq = clk_get_rate(sensor->xclk);
	if (sensor->xclk_freq != 30000000) {
		dev_err(dev, "Unsupported clock frequency: %lu\n",
			sensor->xclk_freq);
		return -EINVAL;
	}

Then

1) in case of an OF platform "xclk" clock frequency can be set directly
   in a board DTS file, please reference to clock-bindings.txt,
2) next you can drop 'clock-frequency' property from the sensor bindings,
3) you can drop 'depends on OF' from drivers/media/i2c/Kconfig,
4) you can drop 'clk_set_rate()' from sensor_power().

The proposed code is slightly more flexible, at least the change gives
a little chance to run the driver successfully on a non-OF platform,
otherwise it is known in advance that the driver is unusable on any
non-OF platforms and thus an explicit CONFIG_OF build dependency makes
sense.

>>> +static const struct of_device_id ov5647_of_match[] = {
>>> +	{ .compatible = "ovti,ov5647" },
>>> +	{ /* sentinel */ },
>>> +};
>>> +MODULE_DEVICE_TABLE(of, ov5647_of_match);
>>> +#endif
>>> +
>>> +/**
>>> + * @short i2c driver structure
>>> + */
>>> +static struct i2c_driver ov5647_driver = {
>>> +	.driver = {
>>> +		.of_match_table = of_match_ptr(ov5647_of_match),
>>
>> Same comment as above, from Kconfig the driver depends on OF.
>>
> 
> I'm sorry but I'm not understanding what you're trying to say.
> 

You may take a look at of_match_ptr() macro definition from include/linux/of.h:

#ifdef CONFIG_OF
...
#define of_match_ptr(_ptr)      (_ptr)
...
#else
...
#define of_match_ptr(_ptr)      NULL
...
#endif

Hence if the code compilation always depends on the enabled CONFIG_OF option,
then of_match_ptr() macro should be dropped:

	.of_match_table = ov5647_of_match,

>>> +		.owner	= THIS_MODULE,
>>
>> .owner is set by the core, please remove it.
>>
> 
> Ok.
> 
>>> +		.name	= "ov5647",
>>
>> May be .name = SENSOR_NAME, ?
>>
>> Otherwise SENSOR_NAME macro is unused and it should be removed.
>>
> 
> I'll change it to .name = SENSOR_NAME,
> 
>>> +	},
>>> +	.probe		= ov5647_probe,
>>> +	.remove		= ov5647_remove,
>>> +	.id_table	= ov5647_id,
>>> +};
>>> +
>>> +module_i2c_driver(ov5647_driver);
>>> +
>>> +MODULE_AUTHOR("Ramiro Oliveira <roliveir@synopsys.com>");
>>> +MODULE_DESCRIPTION("A low-level driver for OmniVision ov5647 sensors");
>>> +MODULE_LICENSE("GPL v2");
>>>
>>

--
With best wishes,
Vladimir

Re: [PATCH v8 2/2] Add support for OV5647 sensor.

[Vladimir Zapolskiy]

Hi Ramiro,

On 02/13/2017 09:14 PM, Ramiro Oliveira wrote:
> Hi Vladimir,
> 
> Thank you for your feedback.
> 
> On 2/13/2017 12:21 PM, Vladimir Zapolskiy wrote:
>> Hello Ramiro,
>>
>> On 02/13/2017 01:25 PM, Ramiro Oliveira wrote:
>>> Modes supported:
>>>  - 640x480 RAW 8
>>>

[snip]

>>> +static int ov5647_probe(struct i2c_client *client,
>>> +			const struct i2c_device_id *id)
>>> +{
>>> +	struct device *dev = &client->dev;
>>> +	struct ov5647 *sensor;
>>> +	int ret;
>>> +	struct v4l2_subdev *sd;
>>> +
>>> +	dev_info(&client->dev, "Installing OmniVision OV5647 camera driver\n");
>>
>> Please remove the informational line, it will pollute the kernel log for no
>> good reason.
>>
> 
> Is it okay if I change it to debug?
> 

Most probably here it is okay to change it to dev_dbg(), however

1) please note that ftrace functionality should provide all the magic for you,
   and by the way this makes dev_dbg() calls from ov5647_write(), ov5647_read(),
   ov5647_stream_on(), ov5647_stream_off() and __sensor_init() all redundant,

2) please move the informational message to the end of the .probe function,
   right before returning success to avoid duplicates on deferred re-probing:

	dev_dbg(&client->dev, "OmniVision OV5647 camera driver probed\n");
	                                                      ^^^^^^^^
[snip]

>>> +
>>> +static const struct i2c_device_id ov5647_id[] = {
>>> +	{ "ov5647", 0 },
>>> +	{ }
>>> +};
>>> +MODULE_DEVICE_TABLE(i2c, ov5647_id);
>>> +
>>> +#if IS_ENABLED(CONFIG_OF)
>>
>> From Kconfig the driver depends on OF.
>>
> 
> You're right. Do you think I should remove the dependency in Kconfig or the
> check here?
> 

Let see...

I've been able to locate only one place where OF dependency is utterly needed:

	ret = of_property_read_u32(dev->of_node, "clock-frequency",
				    &sensor->xclk_freq);
	if (ret) {
		dev_err(dev, "could not get xclk frequency\n");
		return ret;
	}

It might be preferred to change this snippet of code into something like one
below:

	sensor->xclk_freq = clk_get_rate(sensor->xclk);
	if (sensor->xclk_freq != 30000000) {
		dev_err(dev, "Unsupported clock frequency: %lu\n",
			sensor->xclk_freq);
		return -EINVAL;
	}

Then

1) in case of an OF platform "xclk" clock frequency can be set directly
   in a board DTS file, please reference to clock-bindings.txt,
2) next you can drop 'clock-frequency' property from the sensor bindings,
3) you can drop 'depends on OF' from drivers/media/i2c/Kconfig,
4) you can drop 'clk_set_rate()' from sensor_power().

The proposed code is slightly more flexible, at least the change gives
a little chance to run the driver successfully on a non-OF platform,
otherwise it is known in advance that the driver is unusable on any
non-OF platforms and thus an explicit CONFIG_OF build dependency makes
sense.

>>> +static const struct of_device_id ov5647_of_match[] = {
>>> +	{ .compatible = "ovti,ov5647" },
>>> +	{ /* sentinel */ },
>>> +};
>>> +MODULE_DEVICE_TABLE(of, ov5647_of_match);
>>> +#endif
>>> +
>>> +/**
>>> + * @short i2c driver structure
>>> + */
>>> +static struct i2c_driver ov5647_driver = {
>>> +	.driver = {
>>> +		.of_match_table = of_match_ptr(ov5647_of_match),
>>
>> Same comment as above, from Kconfig the driver depends on OF.
>>
> 
> I'm sorry but I'm not understanding what you're trying to say.
> 

You may take a look at of_match_ptr() macro definition from include/linux/of.h:

#ifdef CONFIG_OF
...
#define of_match_ptr(_ptr)      (_ptr)
...
#else
...
#define of_match_ptr(_ptr)      NULL
...
#endif

Hence if the code compilation always depends on the enabled CONFIG_OF option,
then of_match_ptr() macro should be dropped:

	.of_match_table = ov5647_of_match,

>>> +		.owner	= THIS_MODULE,
>>
>> .owner is set by the core, please remove it.
>>
> 
> Ok.
> 
>>> +		.name	= "ov5647",
>>
>> May be .name = SENSOR_NAME, ?
>>
>> Otherwise SENSOR_NAME macro is unused and it should be removed.
>>
> 
> I'll change it to .name = SENSOR_NAME,
> 
>>> +	},
>>> +	.probe		= ov5647_probe,
>>> +	.remove		= ov5647_remove,
>>> +	.id_table	= ov5647_id,
>>> +};
>>> +
>>> +module_i2c_driver(ov5647_driver);
>>> +
>>> +MODULE_AUTHOR("Ramiro Oliveira <roliveir-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>");
>>> +MODULE_DESCRIPTION("A low-level driver for OmniVision ov5647 sensors");
>>> +MODULE_LICENSE("GPL v2");
>>>
>>

--
With best wishes,
Vladimir
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