Hi Ramiro,
please find some review comments below.
On 02/17/2017 03:14 PM, Ramiro Oliveira wrote:
> The OV5647 sensor from Omnivision supports up to 2592x1944 @ 15 fps, RAW 8
> and RAW 10 output formats, and MIPI CSI-2 interface.
>
> The driver adds support for 640x480 RAW 8.
>
> Signed-off-by: Ramiro Oliveira <roliveir@xxxxxxxxxxxx>
> ---
[snip]
> +
> +struct ov5647 {
> + 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;
See a comment about 25MHz vs 30MHz below.
Also I assume you can remove 'xclk_freq' from the struct fields,
it can be replaced by a local variable.
> +};
[snip]
> +
> +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 < 0) {
> + dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
s/i2c read error/i2c write error/
> + __func__, reg);
> + return ret;
> + }
> +
> + ret = i2c_master_recv(client, val, 1);
> + if (ret < 0)
> + dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
> + __func__, reg);
> +
> + return ret;
> +
Please remove the empty line above.
> +}
> +
> +static int ov5647_write_array(struct v4l2_subdev *sd,
> + struct regval_list *regs, int array_size)
> +{
> + int i = 0, ret;
Assignment of 'i' on declaration is not needed, please remove.
> +
> + 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;
> +
> + 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);
Should you add a check of the returned value?
> +
> + dev_dbg(&client->dev, "Stream on");
I would suggest to remove dev_dbg(), because ftrace will report to a user,
when this function is called.
Also dev_dbg() in the middle of two I2C transfers in a row looks as being
placed improperly.
> +
> + 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);
Should you add a check of the returned value?
> +
> + dev_dbg(&client->dev, "Stream off");
I would suggest to remove dev_dbg(), because ftrace will report to a user,
when this function is called.
Also dev_dbg() in the middle of two I2C transfers in a row looks as being
placed improperly.
> +
> + return ov5647_write(sd, 0x300D, 0x01);
> +}
> +
> +static int set_sw_standby(struct v4l2_subdev *sd, bool standby)
> +{
> + int ret;
> + u8 rdval;
> +
> + ret = ov5647_read(sd, 0x0100, &rdval);
> + if (ret < 0)
> + return ret;
> +
> + if (standby)
> + rdval &= ~0x01;
> + else
> + rdval |= 0x01;
> +
> + return ov5647_write(sd, 0x0100, rdval);
> +}
> +
> +static int __sensor_init(struct v4l2_subdev *sd)
> +{
> + int ret;
> + u8 resetval;
> + u8 rdval;
It could be possible to put declarations of 'resetval' and 'rdval' on the same line.
> + 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);
> +}
> +
> +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);
Now clk_set_rate() is redundant, please remove it.
If once it is needed again, please move it to the .probe function, so
it is called only once in the runtime.
> +
> + ret = clk_prepare_enable(ov5647->xclk);
I wonder would it be possible to unload the driver or to unbind the device
and leave the clock unintentionally enabled? If yes, then this is a bug.
> + if (ret < 0) {
> + dev_err(&client->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");
One of two dev_dbg()'s above is apparently redundant.
> + 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;
> +}
> +
[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;
> +
> + sensor = devm_kzalloc(dev, sizeof(*sensor), GFP_KERNEL);
> + if (sensor == NULL)
if (!sensor) is a bit shorter.
> + 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);
> + }
> +
> + sensor->xclk_freq = clk_get_rate(sensor->xclk);
> + if (sensor->xclk_freq != 25000000) {
A comment in "struct ov5647" declaration says about 30MHz, which one is correct?
> + dev_err(dev, "Unsupported clock frequency: %u\n",
> + sensor->xclk_freq);
> + return -EINVAL;
> + }
> +
> + mutex_init(&sensor->lock);
> +
> + 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;
> +
> + dev_dbg(&client->dev, "OmniVision OV5647 camera driver probed\n");
> + return 0;
> +error:
> + media_entity_cleanup(&sd->entity);
> +mutex_remove:
> + mutex_destroy(&sensor->lock);
> + return ret;
> +}
> +
[snip]
The driver looks good in general IMO.
--
With best wishes,
Vladimir
