drm/panel: simple: make it possible to override LCD bus format

The baseboards for the Ka-Ro electronics series of i.MX modules have
their display ports wired to the topmost bits of the R,G,B bit
lanes. Thus no matter what LCD bus width (18 or 24bit) a module
provides, the LCD port can be used without shuffling bit lanes.

Add a function to handle certain quirks of the LCD interface to the
panel driver to be able to override the bus format specified in a
panel's display_mode.

diff --git a/Documentation/devicetree/bindings/display/panel/simple-panel.txt b/Documentation/devicetree/bindings/display/panel/simple-panel.txt
index 1341bbf4aa3d13147de6465d5219989338b9d3b7..e2308c3414d9e213059a19d00e84d4ae33a6aa02 100644 (file)
--- a/Documentation/devicetree/bindings/display/panel/simple-panel.txt
+++ b/Documentation/devicetree/bindings/display/panel/simple-panel.txt
@@ -7,6 +7,8 @@ Optional properties:
 - ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing
 - enable-gpios: GPIO pin to enable or disable the panel
 - backlight: phandle of the backlight device attached to the panel
+- bus-format-override: override the bus_format setting of the panel's
+  display_mode settings
 
 Example:
 

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index fde9c415432b4609508b4d6a202d828898f37eb7..f356a7b32f08db68af20c542e251653d91725404 100644 (file)
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -87,6 +87,8 @@ struct panel_simple {
        struct i2c_adapter *ddc;
 
        struct gpio_desc *enable_gpio;
+
+       u32 bus_fmt_override;
 };
 
 #define SP_DISPLAY_MODE(freq, ha, hfp, hs, hbp, va, vfp, vs, vbp, vr, flgs) { \
@@ -165,7 +167,11 @@ static int panel_simple_get_fixed_modes(struct panel_simple *panel)
        connector->display_info.bpc = panel->desc->bpc;
        connector->display_info.width_mm = panel->desc->size.width;
        connector->display_info.height_mm = panel->desc->size.height;
-       if (panel->desc->bus_format)
+
+       if (panel->bus_fmt_override)
+               drm_display_info_set_bus_formats(&connector->display_info,
+                                                &panel->bus_fmt_override, 1);
+       else if (panel->desc->bus_format)
                drm_display_info_set_bus_formats(&connector->display_info,
                                                 &panel->desc->bus_format, 1);
        connector->display_info.bus_flags = panel->desc->bus_flags;
@@ -298,6 +304,34 @@ static int panel_simple_get_timings(struct drm_panel *panel,
        return p->desc->num_timings;
 }
 
+static inline int panel_simple_check_quirks(struct device *dev,
+                                           struct panel_simple *p)
+{
+       const char *bus_fmt;
+
+       if (of_property_read_string(dev->of_node, "bus-format-override",
+                                   &bus_fmt) == 0) {
+               if (strcmp(bus_fmt, "rgb24") == 0)
+                       p->bus_fmt_override = MEDIA_BUS_FMT_RGB888_1X24;
+               else if (strcmp(bus_fmt, "rgb666") == 0)
+                       p->bus_fmt_override = MEDIA_BUS_FMT_RGB666_1X18;
+               else if (strcmp(bus_fmt, "rgb565") == 0)
+                       p->bus_fmt_override = MEDIA_BUS_FMT_RGB565_1X16;
+               else if (strcmp(bus_fmt, "spwg-18") == 0)
+                       p->bus_fmt_override = MEDIA_BUS_FMT_RGB666_1X7X3_SPWG;
+               else if (strcmp(bus_fmt, "spwg-24") == 0)
+                       p->bus_fmt_override = MEDIA_BUS_FMT_RGB888_1X7X4_SPWG;
+               else if (strcmp(bus_fmt, "jeida-24") == 0)
+                       p->bus_fmt_override = MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA;
+               else
+                       dev_err(dev,
+                               "Unsupported bus-format-override value: '%s'\n",
+                               bus_fmt);
+               return p->bus_fmt_override ? 0 : -EINVAL;
+       }
+       return 0;
+}
+
 static const struct drm_panel_funcs panel_simple_funcs = {
        .disable = panel_simple_disable,
        .unprepare = panel_simple_unprepare,
@@ -353,6 +387,10 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
                }
        }
 
+       err = panel_simple_check_quirks(dev, panel);
+       if (err)
+               goto free_ddc;
+
        drm_panel_init(&panel->base);
        panel->base.dev = dev;
        panel->base.funcs = &panel_simple_funcs;