Re: [PATCH 9/9] drm/bridge: imx: Add i.MX93 MIPI DSI support

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Hi,

Am Dienstag, 18. Juli 2023, 11:00:25 CEST schrieb Ying Liu:
> On Tuesday, July 18, 2023 3:49 PM Alexander Stein <alexander.stein@ew.tq-
group.com> wrote:
> > Hi,
> 
> Hi,
> 
> > thanks for the patch.
> 
> Thanks for your review.
> 
> > Am Montag, 17. Juli 2023, 08:18:31 CEST schrieb Liu Ying:
> > > Freescale i.MX93 SoC embeds a Synopsys Designware MIPI DSI host
> > > controller and a Synopsys Designware MIPI DPHY.  Some configurations
> > > and extensions to them are controlled by i.MX93 media blk-ctrl.
> > > 
> > > Add a DRM bridge for i.MX93 MIPI DSI by using existing DW MIPI DSI
> > > bridge helpers and implementing i.MX93 MIPI DSI specific extensions.
> > > 
> > > Signed-off-by: Liu Ying <victor.liu@nxp.com>
> > > ---
> > > 
> > >  drivers/gpu/drm/bridge/imx/Kconfig          |  10 +
> > >  drivers/gpu/drm/bridge/imx/Makefile         |   1 +
> > >  drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c | 934
> > 
> > ++++++++++++++++++++
> > 
> > >  3 files changed, 945 insertions(+)
> > >  create mode 100644 drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
> > > 
> > > diff --git a/drivers/gpu/drm/bridge/imx/Kconfig
> > > b/drivers/gpu/drm/bridge/imx/Kconfig index
> > 
> > 9fae28db6aa7..5182298c7182
> > 
> > > 100644
> > > --- a/drivers/gpu/drm/bridge/imx/Kconfig
> > > +++ b/drivers/gpu/drm/bridge/imx/Kconfig
> > > @@ -49,4 +49,14 @@ config DRM_IMX8QXP_PIXEL_LINK_TO_DPI
> > > 
> > >       Choose this to enable pixel link to display pixel
> > 
> > interface(PXL2DPI)
> > 
> > >       found in Freescale i.MX8qxp processor.
> > > 
> > > +config DRM_IMX93_MIPI_DSI
> > > +   tristate "Freescale i.MX93 specific extensions for Synopsys DW MIPI
> > 
> > DSI"
> > 
> > > +   depends on OF
> > > +   depends on COMMON_CLK
> > > +   select DRM_DW_MIPI_DSI
> > > +   select GENERIC_PHY_MIPI_DPHY
> > > +   help
> > > +     Choose this to enable MIPI DSI controller found in Freescale
> > 
> > i.MX93
> > 
> > > +     processor.
> > > +
> > > 
> > >  endif # ARCH_MXC || COMPILE_TEST
> > > 
> > > diff --git a/drivers/gpu/drm/bridge/imx/Makefile
> > > b/drivers/gpu/drm/bridge/imx/Makefile index
> > 
> > 8e2ebf3399a1..2b0c2e44aa1b
> > 
> > > 100644
> > > --- a/drivers/gpu/drm/bridge/imx/Makefile
> > > +++ b/drivers/gpu/drm/bridge/imx/Makefile
> > > @@ -4,3 +4,4 @@ obj-$(CONFIG_DRM_IMX8QXP_LDB) += imx8qxp-ldb.o
> > > 
> > >  obj-$(CONFIG_DRM_IMX8QXP_PIXEL_COMBINER) += imx8qxp-pixel-
> > 
> > combiner.o
> > 
> > >  obj-$(CONFIG_DRM_IMX8QXP_PIXEL_LINK) += imx8qxp-pixel-link.o
> > >  obj-$(CONFIG_DRM_IMX8QXP_PIXEL_LINK_TO_DPI) += imx8qxp-pxl2dpi.o
> > > 
> > > +obj-$(CONFIG_DRM_IMX93_MIPI_DSI) += imx93-mipi-dsi.o
> > > diff --git a/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
> > > b/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c new file mode 100644
> > > index 000000000000..77f59e3407a0
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
> > > 
> > > [snip]
> > > 
> > > +static int imx93_dsi_probe(struct platform_device *pdev)
> > > +{
> > > +   struct device *dev = &pdev->dev;
> > > +   struct device_node *np = dev->of_node;
> > > +   struct imx93_dsi *dsi;
> > > +   int ret;
> > > +
> > > +   dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
> > > +   if (!dsi)
> > > +           return -ENOMEM;
> > > +
> > > +   dsi->regmap = syscon_regmap_lookup_by_phandle(np, "fsl,media-
> > 
> > blk-
> > ctrl");
> > 
> > > +   if (IS_ERR(dsi->regmap)) {
> > > +           ret = PTR_ERR(dsi->regmap);
> > 
> > > +           DRM_DEV_ERROR(dev, "failed to get block ctrl regmap:
> > %d\n", ret);
> > 
> > Could you use dev_err_probe here instead?
> 
> Maybe, it's better to keep using DRM_DEV_ERROR to achieve consistent
> error log format across the driver which is implemented in drm_dev_printk().
> I see other DRM drivers do the same.

I see your point. On the other hand the benefit of dev_err_probe() is that the 
message of deferred probe can be seen in /sys/kernel/debug/devices_deferred.
Your check against EPROBE_DEFER will hide the message if something is not 
correct.

Maybe a to be introduced DRM_DEV_ERROR_PROBE might be useful.

Best regards,
Alexander

> > > +           return ret;
> > > +   }
> > > +
> > > +   dsi->clk_pixel = devm_clk_get(dev, "pix");
> > > +   if (IS_ERR(dsi->clk_pixel)) {
> > > +           ret = PTR_ERR(dsi->clk_pixel);
> > > +           if (ret != -EPROBE_DEFER)
> > 
> > > +                   DRM_DEV_ERROR(dev, "failed to get pixel clock:
> > %d\n", ret);
> > 
> > Could you use dev_err_probe here instead?
> 
> Ditto.
> 
> > > +           return ret;
> > > +   }
> > > +
> > > +   dsi->clk_cfg = devm_clk_get(dev, "phy_cfg");
> > > +   if (IS_ERR(dsi->clk_cfg)) {
> > > +           ret = PTR_ERR(dsi->clk_cfg);
> > > +           if (ret != -EPROBE_DEFER)
> > 
> > > +                   DRM_DEV_ERROR(dev, "failed to get phy cfg clock:
> > %d\n", ret);
> > 
> > > +           return ret;
> > > +   }
> > > +
> > > +   dsi->clk_ref = devm_clk_get(dev, "phy_ref");
> > > +   if (IS_ERR(dsi->clk_ref)) {
> > > +           ret = PTR_ERR(dsi->clk_ref);
> > > +           if (ret != -EPROBE_DEFER)
> > 
> > > +                   DRM_DEV_ERROR(dev, "failed to get phy ref clock:
> > %d\n", ret);
> > 
> > Could you use dev_err_probe here instead?
> 
> Ditto.
> 
> > > +           return ret;
> > > +   }
> > > +
> > > +   dsi->ref_clk_rate = clk_get_rate(dsi->clk_ref);
> > > +   if (dsi->ref_clk_rate < REF_CLK_RATE_MIN ||
> > > +       dsi->ref_clk_rate > REF_CLK_RATE_MAX) {
> > > +           DRM_DEV_ERROR(dev, "invalid phy ref clock rate %lu\n",
> > > +                         dsi->ref_clk_rate);
> > > +           return -EINVAL;
> > > +   }
> > > +   DRM_DEV_DEBUG_DRIVER(dev, "phy ref clock rate: %lu\n", dsi-
> > >
> > >ref_clk_rate);
> > >
> > > +
> > > +   dsi->dev = dev;
> > > +   dsi->pdata.max_data_lanes = 4;
> > > +   dsi->pdata.mode_valid = imx93_dsi_mode_valid;
> > > +   dsi->pdata.mode_fixup = imx93_dsi_mode_fixup;
> > > +   dsi->pdata.get_input_bus_fmts = imx93_dsi_get_input_bus_fmts;
> > > +   dsi->pdata.phy_ops = &imx93_dsi_phy_ops;
> > > +   dsi->pdata.host_ops = &imx93_dsi_host_ops;
> > > +   dsi->pdata.priv_data = dsi;
> > > +   platform_set_drvdata(pdev, dsi);
> > > +
> > > +   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);
> > 
> > Could you use dev_err_probe here instead?
> 
> Ditto.
> 
> Regards,
> Liu Ying
> 
> > Best regards,
> > Alexander
> > 
> > > +           return ret;
> > > +   }
> > > +
> > > +   return 0;
> > > +}
> > > +
> > > +static void imx93_dsi_remove(struct platform_device *pdev)
> > > +{
> > > +   struct imx93_dsi *dsi = platform_get_drvdata(pdev);
> > > +
> > > +   dw_mipi_dsi_remove(dsi->dmd);
> > > +}
> > > +
> > > +static const struct of_device_id imx93_dsi_dt_ids[] = {
> > > +   { .compatible = "fsl,imx93-mipi-dsi", },
> > > +   { /* sentinel */ }
> > > +};
> > > +MODULE_DEVICE_TABLE(of, imx93_dsi_dt_ids);
> > > +
> > > +static struct platform_driver imx93_dsi_driver = {
> > > +   .probe  = imx93_dsi_probe,
> > > +   .remove_new = imx93_dsi_remove,
> > > +   .driver = {
> > > +           .of_match_table = imx93_dsi_dt_ids,
> > > +           .name = "imx93_mipi_dsi",
> > > +   },
> > > +};
> > > +module_platform_driver(imx93_dsi_driver);
> > > +
> > > +MODULE_DESCRIPTION("Freescale i.MX93 MIPI DSI driver");
> > > +MODULE_AUTHOR("Liu Ying <victor.liu@nxp.com>");
> > > +MODULE_LICENSE("GPL");
> > 
> > --
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> > Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
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TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
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Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
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