From 073667fce1667eab31d6a62cdd7fb795933ec7e8 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Thu, 26 Jun 2025 12:05:00 +0200 Subject: [PATCH] drm/panel: panel-simple: make panel_dpi_probe return a panel_desc If the panel-simple driver is probed from a panel-dpi compatible, the driver will use an empty panel_desc structure as a descriminant. It will then allocate and fill another panel_desc as part of its probe. However, that allocation needs to happen after the panel_simple structure has been allocated, since panel_dpi_probe(), the function doing the panel_desc allocation and initialization, takes a panel_simple pointer as an argument. This pointer is used to fill the panel_simple->desc pointer that is still initialized with the empty panel_desc when panel_dpi_probe() is called. Since commit de04bb0089a9 ("drm/panel/panel-simple: Use the new allocation in place of devm_kzalloc()"), we will need the panel connector type found in panel_desc to allocate panel_simple. This creates a circular dependency where we need panel_desc to create panel_simple, and need panel_simple to create panel_desc. Let's break that dependency by making panel_dpi_probe simply return the panel_desc it initialized and move the panel_simple->desc assignment to the caller. This will not fix the breaking commit entirely, but will move us towards the right direction. Fixes: de04bb0089a9 ("drm/panel/panel-simple: Use the new allocation in place of devm_kzalloc()") Reviewed-by: Javier Martinez Canillas Tested-by: Francesco Dolcini # Toradex Colibri iMX6 Link: https://lore.kernel.org/r/20250626-drm-panel-simple-fixes-v2-2-5afcaa608bdc@kernel.org Signed-off-by: Maxime Ripard --- drivers/gpu/drm/panel/panel-simple.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c index 0a3b26bb4d73..89188e683822 100644 --- a/drivers/gpu/drm/panel/panel-simple.c +++ b/drivers/gpu/drm/panel/panel-simple.c @@ -432,8 +432,7 @@ static const struct drm_panel_funcs panel_simple_funcs = { static struct panel_desc panel_dpi; -static int panel_dpi_probe(struct device *dev, - struct panel_simple *panel) +static struct panel_desc *panel_dpi_probe(struct device *dev) { struct display_timing *timing; const struct device_node *np; @@ -445,17 +444,17 @@ static int panel_dpi_probe(struct device *dev, np = dev->of_node; desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL); if (!desc) - return -ENOMEM; + return ERR_PTR(-ENOMEM); timing = devm_kzalloc(dev, sizeof(*timing), GFP_KERNEL); if (!timing) - return -ENOMEM; + return ERR_PTR(-ENOMEM); ret = of_get_display_timing(np, "panel-timing", timing); if (ret < 0) { dev_err(dev, "%pOF: no panel-timing node found for \"panel-dpi\" binding\n", np); - return ret; + return ERR_PTR(ret); } desc->timings = timing; @@ -473,9 +472,7 @@ static int panel_dpi_probe(struct device *dev, /* We do not know the connector for the DT node, so guess it */ desc->connector_type = DRM_MODE_CONNECTOR_DPI; - panel->desc = desc; - - return 0; + return desc; } #define PANEL_SIMPLE_BOUNDS_CHECK(to_check, bounds, field) \ @@ -613,10 +610,13 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc) if (desc == &panel_dpi) { /* Handle the generic panel-dpi binding */ - err = panel_dpi_probe(dev, panel); - if (err) + desc = panel_dpi_probe(dev); + if (IS_ERR(desc)) { + err = PTR_ERR(desc); goto free_ddc; - desc = panel->desc; + } + + panel->desc = desc; } else { if (!of_get_display_timing(dev->of_node, "panel-timing", &dt)) panel_simple_parse_panel_timing_node(dev, panel, &dt); -- 2.25.1