Re: [PATCH] drm/rockchip: dsi: convert to dev_err_probe in probe function

[Dragan Simic <dsimic@manjaro.org>]

Hello Heiko,

Thanks for the patch.  Please, see a couple of comments below.

On 2024-11-08 15:44, Heiko Stuebner wrote:
> From: Heiko Stuebner <heiko.stuebner@cherry.de>
> 
> DRM_DEV_ERROR is deprecated and using dev_err_probe saves quite a 
> number
> of lines too, so convert the error prints for the dsi-driver.
> 
> Signed-off-by: Heiko Stuebner <heiko.stuebner@cherry.de>
> ---
>  .../gpu/drm/rockchip/dw-mipi-dsi-rockchip.c   | 80 ++++++-------------
>  1 file changed, 26 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> index 58a44af0e9ad..3224ab749352 100644
> --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> @@ -1356,17 +1356,15 @@ static int dw_mipi_dsi_rockchip_probe(struct
> platform_device *pdev)
>  	struct resource *res;
>  	const struct rockchip_dw_dsi_chip_data *cdata =
>  				of_device_get_match_data(dev);
> -	int ret, i;
> +	int i;
> 
>  	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
>  	if (!dsi)
>  		return -ENOMEM;
> 
>  	dsi->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
> -	if (IS_ERR(dsi->base)) {
> -		DRM_DEV_ERROR(dev, "Unable to get dsi registers\n");
> -		return PTR_ERR(dsi->base);
> -	}
> +	if (IS_ERR(dsi->base))
> +		return dev_err_probe(dev, PTR_ERR(dsi->base), "Unable to get dsi 
> registers\n");
> 
>  	i = 0;
>  	while (cdata[i].reg) {
> @@ -1378,67 +1376,47 @@ static int dw_mipi_dsi_rockchip_probe(struct
> platform_device *pdev)
>  		i++;
>  	}
> 
> -	if (!dsi->cdata) {
> -		DRM_DEV_ERROR(dev, "no dsi-config for %s node\n", np->name);
> -		return -EINVAL;
> -	}
> +	if (!dsi->cdata)
> +		return dev_err_probe(dev, -EINVAL, "No dsi-config for %s node\n", 
> np->name);
> 
>  	/* try to get a possible external dphy */
>  	dsi->phy = devm_phy_optional_get(dev, "dphy");
> -	if (IS_ERR(dsi->phy)) {
> -		ret = PTR_ERR(dsi->phy);
> -		DRM_DEV_ERROR(dev, "failed to get mipi dphy: %d\n", ret);
> -		return ret;
> -	}
> +	if (IS_ERR(dsi->phy))
> +		return dev_err_probe(dev, PTR_ERR(dsi->phy), "Failed to get mipi 
> dphy\n");

After spending a couple of days thinking about it, I think this
particular change should be extracted into a separate patch and
submitted additionally for the inclusion into stable kernels.

My reasoning behind that is the "spamming" of the kernel log with
multiple suspiciously looking error messages when getting the dphy
results in deferred probing, which IMHO looks really bad and may
cause false impression of underlying issues.

If you agree with this suggestion, please feel free to use the
relevant parts of the description of the patch I submitted and
withdrawn earlier, [*] to provide the required rationale for the
inclusion into stable kernels.

[*] 
https://lore.kernel.org/linux-rockchip/559094275c3e41cae7c89e904341f89a1240a51a.1731073565.git.dsimic@manjaro.org/

>  	dsi->pclk = devm_clk_get(dev, "pclk");
> -	if (IS_ERR(dsi->pclk)) {
> -		ret = PTR_ERR(dsi->pclk);
> -		DRM_DEV_ERROR(dev, "Unable to get pclk: %d\n", ret);
> -		return ret;
> -	}
> +	if (IS_ERR(dsi->pclk))
> +		return dev_err_probe(dev, PTR_ERR(dsi->pclk), "Unable to get 
> pclk\n");
> 
>  	dsi->pllref_clk = devm_clk_get(dev, "ref");
>  	if (IS_ERR(dsi->pllref_clk)) {
> -		if (dsi->phy) {
> +		if (dsi->phy)
>  			/*
>  			 * if external phy is present, pll will be
>  			 * generated there.
>  			 */
>  			dsi->pllref_clk = NULL;
> -		} else {
> -			ret = PTR_ERR(dsi->pllref_clk);
> -			DRM_DEV_ERROR(dev,
> -				      "Unable to get pll reference clock: %d\n",
> -				      ret);
> -			return ret;
> -		}
> +		else
> +			return dev_err_probe(dev, PTR_ERR(dsi->pllref_clk),
> +					     "Unable to get pll reference clock\n");
>  	}
> 
>  	if (dsi->cdata->flags & DW_MIPI_NEEDS_PHY_CFG_CLK) {
>  		dsi->phy_cfg_clk = devm_clk_get(dev, "phy_cfg");
> -		if (IS_ERR(dsi->phy_cfg_clk)) {
> -			ret = PTR_ERR(dsi->phy_cfg_clk);
> -			DRM_DEV_ERROR(dev,
> -				      "Unable to get phy_cfg_clk: %d\n", ret);
> -			return ret;
> -		}
> +		if (IS_ERR(dsi->phy_cfg_clk))
> +			return dev_err_probe(dev, PTR_ERR(dsi->phy_cfg_clk),
> +					     "Unable to get phy_cfg_clk\n");
>  	}
> 
>  	if (dsi->cdata->flags & DW_MIPI_NEEDS_GRF_CLK) {
>  		dsi->grf_clk = devm_clk_get(dev, "grf");
> -		if (IS_ERR(dsi->grf_clk)) {
> -			ret = PTR_ERR(dsi->grf_clk);
> -			DRM_DEV_ERROR(dev, "Unable to get grf_clk: %d\n", ret);
> -			return ret;
> -		}
> +		if (IS_ERR(dsi->grf_clk))
> +			return dev_err_probe(dev, PTR_ERR(dsi->grf_clk), "Unable to get 
> grf_clk\n");
>  	}
> 
>  	dsi->grf_regmap = syscon_regmap_lookup_by_phandle(np, 
> "rockchip,grf");
> -	if (IS_ERR(dsi->grf_regmap)) {
> -		DRM_DEV_ERROR(dev, "Unable to get rockchip,grf\n");
> -		return PTR_ERR(dsi->grf_regmap);
> -	}
> +	if (IS_ERR(dsi->grf_regmap))
> +		return dev_err_probe(dev, PTR_ERR(dsi->grf_regmap), "Unable to get 
> rockchip,grf\n");
> 
>  	dsi->dev = dev;
>  	dsi->pdata.base = dsi->base;
> @@ -1451,24 +1429,18 @@ static int dw_mipi_dsi_rockchip_probe(struct
> platform_device *pdev)
>  	mutex_init(&dsi->usage_mutex);
> 
>  	dsi->dphy = devm_phy_create(dev, NULL, &dw_mipi_dsi_dphy_ops);
> -	if (IS_ERR(dsi->dphy)) {
> -		DRM_DEV_ERROR(&pdev->dev, "failed to create PHY\n");
> -		return PTR_ERR(dsi->dphy);
> -	}
> +	if (IS_ERR(dsi->dphy))
> +		return dev_err_probe(dev, PTR_ERR(dsi->dphy), "Failed to create 
> PHY\n");
> 
>  	phy_set_drvdata(dsi->dphy, dsi);
>  	phy_provider = devm_of_phy_provider_register(dev, 
> of_phy_simple_xlate);
>  	if (IS_ERR(phy_provider))
> -		return PTR_ERR(phy_provider);
> +		return dev_err_probe(dev, PTR_ERR(phy_provider),
> +				     "Failed to register phy-provider\n");
> 
>  	dsi->dmd = dw_mipi_dsi_probe(pdev, &dsi->pdata);
> -	if (IS_ERR(dsi->dmd)) {
> -		ret = PTR_ERR(dsi->dmd);
> -		if (ret != -EPROBE_DEFER)
> -			DRM_DEV_ERROR(dev,
> -				      "Failed to probe dw_mipi_dsi: %d\n", ret);
> -		return ret;
> -	}
> +	if (IS_ERR(dsi->dmd))
> +		return dev_err_probe(dev, PTR_ERR(dsi->dmd), "Failed to probe 
> dw_mipi_dsi\n");
> 
>  	return 0;
>  }

Regardless of the above-suggested split into a patch series
ending up accepted or not, the introduced changes are looking
good to me, so please feel free to include my

Reviewed-by: Dragan Simic <dsimic@manjaro.org>

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