Hi, On Thu, Sep 12, 2019 at 07:51:31PM +0200, Jernej Skrabec wrote: > + dev->regmap = devm_regmap_init_mmio(dev->dev, dev->base, > + &deinterlace_regmap_config); > + if (IS_ERR(dev->regmap)) { > + dev_err(dev->dev, "Couldn't create deinterlace regmap\n"); > + > + return PTR_ERR(dev->regmap); > + } > + > + ret = clk_prepare_enable(dev->bus_clk); > + if (ret) { > + dev_err(dev->dev, "Failed to enable bus clock\n"); > + > + return ret; > + } Do you need to keep the bus clock enabled all the time? Usually, for the SoCs that have a reset line, you only need it to read / write to the registers, not to have the controller actually running. If you don't, then regmap_init_mmio_clk will take care of that for you. > + clk_set_rate(dev->mod_clk, 300000000); > + > + ret = clk_prepare_enable(dev->mod_clk); > + if (ret) { > + dev_err(dev->dev, "Failed to enable mod clock\n"); > + > + goto err_bus_clk; > + } > + > + ret = clk_prepare_enable(dev->ram_clk); > + if (ret) { > + dev_err(dev->dev, "Failed to enable ram clock\n"); > + > + goto err_mod_clk; > + } > + > + ret = reset_control_reset(dev->rstc); > + if (ret) { > + dev_err(dev->dev, "Failed to apply reset\n"); > + > + goto err_ram_clk; > + } This could be moved to a runtime_pm hook, with get_sync called in the open. That way you won't leave the device powered on if it's unused. > +struct deinterlace_dev { > + struct v4l2_device v4l2_dev; > + struct video_device vfd; > + struct device *dev; > + struct v4l2_m2m_dev *m2m_dev; > + > + /* Device file mutex */ > + struct mutex dev_mutex; > + > + void __iomem *base; > + struct regmap *regmap; Do you need to store the base address in that structure if you're using the regmap? Maxime