Re: [PATCH v4 2/2] Add support for OV5647 sensor

From: Ramiro Oliveira
Date: Mon Nov 21 2016 - 10:01:12 EST


Hi Pavel!

On 11/15/2016 12:10 PM, Pavel Machek wrote:
> Hi!
>
>> Add support for OV5647 sensor.
>>
>
>> +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;
>> +}
>
> Sorry, this is wrong. It should something <0 any time error is detected.
>
>> +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;
>> +}
>
> For example this expects <0 on error.
>
>> +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)
>> + ret = ov5647_write(sd, 0x0100, rdval&0xfe);
>> + else
>> + ret = ov5647_write(sd, 0x0100, rdval|0x01);
>> +
>> + return ret;
>
> if (standby)
> rdval &= 0xfe;
> else
> rdval |= 0x01;
>
> ret = ov5647_write(sd, 0x0100, rdval);
>
> ?
>
>
>> +/**
>> + * @short Store information about the video data format.
>> + */
>> +static struct sensor_format_struct {
>> + __u8 *desc;
>> + u32 mbus_code;
>
> u8 is suitable here.
>
>
>> + ov5647_read(sd, 0x0100, &resetval);
>> + if (!resetval&0x01) {
>
> add ()s here.
>
>> +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) {
>> + dev_dbg(&client->dev, "OV5647 power on!\n");
>> +
>> + ret = ov5647_write_array(sd, sensor_oe_enable_regs,
>> + ARRAY_SIZE(sensor_oe_enable_regs));
>> +
>> + ret = __sensor_init(sd);
>> +
>> + if (ret < 0)
>> + dev_err(&client->dev,
>> + "Camera not available! Check Power!\n");
>> + } else {
>> + 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");
>
> dev_err for errors? Little less "!"s in the output?
>
>> +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);
>> + reg->val = val;
>> + reg->size = 1;
>> + return ret;
>> +}
>
> Filling reg->* when read failed is strange.
>
>> +static int sensor_set_register(struct v4l2_subdev *sd,
>> + const struct v4l2_dbg_register *reg)
>> +{
>> + ov5647_write(sd, reg->reg & 0xff, reg->val & 0xff);
>> + return 0;
>> +}
>
> error handling?
>
> Best regards,
> Pavel
>

Thanks for the feedback, I've corrected all the issues you pointed out, except
the one regarding the error handling in the ov5647_write function.

Best Regards,
Ramiro