Re: [PATCH v1 3/5] gpu/drm: host1x: mipi: add Tegra20/Tegra30 MIPI calibration logic

[Mikko Perttunen <mperttunen@nvidia.com>]

On Thursday, July 17, 2025 11:21 PM Svyatoslav Ryhel wrote:
> ...
> @@ -311,6 +330,43 @@ int tegra_mipi_finish_calibration(struct
> tegra_mipi_device *device) }
>  EXPORT_SYMBOL(tegra_mipi_finish_calibration);
> 
> +static int tegra20_mipi_calibration(struct tegra_mipi_device *device)
> +{
> +	struct tegra_mipi *mipi = device->mipi;
> +	const struct tegra_mipi_soc *soc = mipi->soc;
> +	u32 value;
> +	int err;
> +
> +	err = clk_enable(mipi->csi_clk);
> +	if (err < 0)
> +		return err;
> +
> +	mutex_lock(&mipi->lock);
> +
> +	value = MIPI_CAL_CONFIG_TERMOS(soc->termos);
> +	tegra_mipi_writel(mipi, value, CSI_CILA_MIPI_CAL_CONFIG);
> +
> +	value = MIPI_CAL_CONFIG_TERMOS(soc->termos);
> +	tegra_mipi_writel(mipi, value, CSI_CILB_MIPI_CAL_CONFIG);
> +
> +	value = MIPI_CAL_CONFIG_HSPDOS(soc->hspdos) |
> +		MIPI_CAL_CONFIG_HSPUOS(soc->hspuos);
> +	tegra_mipi_writel(mipi, value, CSI_DSI_MIPI_CAL_CONFIG);
> +
> +	value = MIPI_CAL_BIAS_PAD_DRV_DN_REF(soc->pad_drive_down_ref) |
> +		MIPI_CAL_BIAS_PAD_DRV_UP_REF(soc->pad_drive_up_ref);
> +	tegra_mipi_writel(mipi, value, CSI_MIPIBIAS_PAD_CONFIG);
> +
> +	tegra_mipi_writel(mipi, 0x0, CSI_CIL_PAD_CONFIG);
> +
> +	mutex_unlock(&mipi->lock);
> +
> +	clk_disable(mipi->csi_clk);
> +	clk_disable(mipi->clk);
> +
> +	return 0;
> +}
> +

Where does this sequence come from? It looks a bit strange to me, since it 
doesn't trigger calibration at all. It would be useful to mention the source 
in the commit message.

Mikko