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Date: Mon, 13 Feb 2017 14:21:12 +0200
From: Vladimir Zapolskiy <vladimir_zapolskiy@...tor.com>
To: Ramiro Oliveira <Ramiro.Oliveira@...opsys.com>,
<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-media@...r.kernel.org>
CC: <CARLOS.PALMINHA@...opsys.com>, Arnd Bergmann <arnd@...db.de>,
"David S. Miller" <davem@...emloft.net>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Guenter Roeck <linux@...ck-us.net>,
Hans Verkuil <hans.verkuil@...co.com>,
Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>,
Kamil Debski <k.debski@...sung.com>,
Mark Rutland <mark.rutland@....com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Pavel Machek <pavel@....cz>,
Robert Jarzmik <robert.jarzmik@...e.fr>,
Rob Herring <robh+dt@...nel.org>,
Sakari Ailus <sakari.ailus@...ux.intel.com>,
Steve Longerbeam <slongerbeam@...il.com>
Subject: Re: [PATCH v8 2/2] Add support for OV5647 sensor.
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@...opsys.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The comment contents is probably outdated, because it does not describe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@...opsys.com>");
> +MODULE_DESCRIPTION("A low-level driver for OmniVision ov5647 sensors");
> +MODULE_LICENSE("GPL v2");
>
--
With best wishes,
Vladimir
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