drivers: display: st7735 add rotation at runtime

[th-fischer2020]

Is your feature request related to a problem? Please describe. I am using a type st7735r display in my project and face the need of display-rotation at runtime. The display api provides the function called st7735r_set_orientation() which is not implemented/ not supported yet. Per default the Driver is implemented in landscape-mode. So that is okay for me. In addition, i only need the 180°-rotation. Softwarerotation is not an option for me. Currently i have zephyr 2.6.0 in use.

Describe the solution you'd like I temporary implemented the solution als follows:

static int st7735r_set_orientation(const struct device *dev,
                   const enum display_orientation orientation)
{
    struct st7735r_config *config = (struct st7735r_config *)dev->config;
    struct st7735r_data *data = (struct st7735r_data *)dev->data;
    int ret = 0;
    uint8_t madctl = config->madctl;

    madctl &= ~(ST7735R_MADCTL_MV |
                ST7735R_MADCTL_MX |
                ST7735R_MADCTL_MY);

    switch (orientation)
    {
    case DISPLAY_ORIENTATION_NORMAL:
        madctl |= ST7735R_MADCTL_MX | ST7735R_MADCTL_MV;
        break;
    case DISPLAY_ORIENTATION_ROTATED_90:
        return -ENOTSUP;
        break;
    case DISPLAY_ORIENTATION_ROTATED_180:
        madctl |= ST7735R_MADCTL_MY | ST7735R_MADCTL_MV;
        break;
    case DISPLAY_ORIENTATION_ROTATED_270:
        return -ENOTSUP;
        break;
    default:
        return -ENOTSUP;
        break;
    }

    ret = st7735r_transmit(data, ST7735R_CMD_MADCTL, &madctl, sizeof(madctl));
    if (ret < 0) {
        return ret;
    }

    return 0;
}

Describe alternatives you've considered I know about the possibility to rotate the screen by DeviceTree, but i neet to rotate at runtime. I thinke the final solution is not as trivial as mentioned above, because the DeviceTree-Settings are defined as DISPLAY_ORIENTATION_NORMAL.

[gmarull]

ILI9xxx displays support rotation, so you may look at the DT part there. Would you mind opening a PR?

[th-fischer2020]

I would be very pleased if a PR will come. Thank you

[gmarull]

I would be very pleased if a PR will come. Thank you

Can you do it yourself?

[th-fischer2020]

Yes, I will do it.