Re: [PATCH v15 2/2] media: i2c: Add OV02A10 image sensor driver

Andy Shevchenko
2020-10-23T14:31:21Z

On Tue, Oct 13, 2020 at 09:05:03PM +0800, Dongchun Zhu wrote:
> Add a V4L2 sub-device driver for OmniVision OV02A10 image sensor.

...

> +#define OV02A10_ID_MASK 0xffff

GENMASK()

(And include bits.h for that)

...

> +static int __ov02a10_start_stream(struct ov02a10 *ov02a10)
> +{
> + struct i2c_client *client = v4l2_get_subdevdata(&ov02a10->subdev);
> + const struct ov02a10_reg_list *reg_list;
> + int ret;
> +
> + /* Apply default values of current mode */
> + reg_list = &ov02a10->cur_mode->reg_list;
> + ret = ov02a10_write_array(ov02a10, reg_list);
> + if (ret)
> + return ret;
> +
> + /* Apply customized values from user */
> + ret = __v4l2_ctrl_handler_setup(ov02a10->subdev.ctrl_handler);
> + if (ret)
> + return ret;
> +
> + /* Set orientation to 180 degree */
> + if (ov02a10->upside_down) {
> + ret = i2c_smbus_write_byte_data(client, REG_MIRROR_FLIP_CONTROL,
> + REG_MIRROR_FLIP_ENABLE);
> + if (ret) {

Shouldn't you use 'ret < 0' here as well?

> + dev_err(&client->dev, "failed to set orientation\n");
> + return ret;
> + }
> + ret = i2c_smbus_write_byte_data(client, REG_GLOBAL_EFFECTIVE,
> + REG_ENABLE);
> + if (ret < 0)
> + return ret;
> + }
> +
> + /* Set MIPI TX speed according to DT property */
> + if (ov02a10->mipi_clock_voltage != OV02A10_MIPI_TX_SPEED_DEFAULT) {
> + ret = i2c_smbus_write_byte_data(client, TX_SPEED_AREA_SEL,
> + ov02a10->mipi_clock_voltage);
> + if (ret < 0)
> + return ret;
> + }
> +
> + /* Set stream on register */
> + return i2c_smbus_write_byte_data(client, REG_SC_CTRL_MODE,
> + SC_CTRL_MODE_STREAMING);
> +}

...

> +/*

Was your intention to declare it as a kernel doc?

> + * ov02a10_set_exposure - Function called when setting exposure time
> + * @priv: Pointer to device structure
> + * @val: Variable for exposure time, in the unit of micro-second
> + *
> + * Set exposure time based on input value.
> + *
> + * Return: 0 on success
> + */
> +static int ov02a10_set_exposure(struct ov02a10 *ov02a10, int val)

...

> +static int ov02a10_check_hwcfg(struct device *dev, struct ov02a10 *ov02a10)
> +{
> + struct fwnode_handle *ep;
> + struct fwnode_handle *fwnode = dev_fwnode(dev);
> + struct v4l2_fwnode_endpoint bus_cfg = {
> + .bus_type = V4L2_MBUS_CSI2_DPHY,
> + };
> + unsigned int i, j;
> + int ret;

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

Basically you can avoid this check, but it's up to you.

> + ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
> + if (!ep)
> + return -ENXIO;
> +
> + ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
> + fwnode_handle_put(ep);
> + if (ret)
> + return ret;
> +
> + for (i = 0; i < ARRAY_SIZE(link_freq_menu_items); i++) {
> + for (j = 0; j < bus_cfg.nr_of_link_frequencies; j++) {
> + if (link_freq_menu_items[i] ==
> + bus_cfg.link_frequencies[j]) {
> + ov02a10->freq_index = i;
> + break;
> + }
> + }
> +
> + if (j == bus_cfg.nr_of_link_frequencies) {
> + dev_err(dev, "no link frequency %lld supported\n",
> + link_freq_menu_items[i]);
> + ret = -EINVAL;
> + break;
> + }
> + }
> +
> + v4l2_fwnode_endpoint_free(&bus_cfg);
> +
> + return ret;
> +}

...

> + fwnode_property_read_u32(dev_fwnode(dev), "rotation", &rotation);

Same Q as per previous reviews. Why device property API can't be used here?

And everywhere else when you have
fwnode_property_read_*(dev_fwnode(dev), ...)
calls.

--
With Best Regards,
Andy Shevchenko