drm/imx: imx-ldb: allow to determine bus format from the connected panel

This patch makes the fsl,data-width and fsl,data-mapping device tree
properties optional if a panel is connected to the ldb output port
via the of_graph bindings. The data mapping is determined from the
display_info.bus_format field provided by the panel.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index 544282bd4f7f19ccc0bb9bfc0720ab4e6f51d5e5..abacc8f674698c98c9444f12629f7895fcbe67a6 100644 (file)
--- a/drivers/gpu/drm/imx/imx-ldb.c
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -63,6 +63,7 @@ struct imx_ldb_channel {
        int edid_len;
        struct drm_display_mode mode;
        int mode_valid;
+       int bus_format;
 };
 
 struct bus_mux {
@@ -96,7 +97,11 @@ static int imx_ldb_connector_get_modes(struct drm_connector *connector)
 
        if (imx_ldb_ch->panel && imx_ldb_ch->panel->funcs &&
            imx_ldb_ch->panel->funcs->get_modes) {
+               struct drm_display_info *di = &connector->display_info;
+
                num_modes = imx_ldb_ch->panel->funcs->get_modes(imx_ldb_ch->panel);
+               if (!imx_ldb_ch->bus_format && di->num_bus_formats)
+                       imx_ldb_ch->bus_format = di->bus_formats[0];
                if (num_modes > 0)
                        return num_modes;
        }
@@ -173,21 +178,33 @@ static void imx_ldb_encoder_prepare(struct drm_encoder *encoder)
 {
        struct imx_ldb_channel *imx_ldb_ch = enc_to_imx_ldb_ch(encoder);
        struct imx_ldb *ldb = imx_ldb_ch->ldb;
+       int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
        u32 bus_format;
 
-       switch (imx_ldb_ch->chno) {
-       case 0:
-               bus_format = (ldb->ldb_ctrl & LDB_DATA_WIDTH_CH0_24) ?
-                       MEDIA_BUS_FMT_RGB888_1X24 : MEDIA_BUS_FMT_RGB666_1X18;
+       switch (imx_ldb_ch->bus_format) {
+       default:
+               dev_warn(ldb->dev,
+                        "could not determine data mapping, default to 18-bit \"spwg\"\n");
+               /* fallthrough */
+       case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
+               bus_format = MEDIA_BUS_FMT_RGB666_1X18;
                break;
-       case 1:
-               bus_format = (ldb->ldb_ctrl & LDB_DATA_WIDTH_CH1_24) ?
-                       MEDIA_BUS_FMT_RGB888_1X24 : MEDIA_BUS_FMT_RGB666_1X18;
+       case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
+               bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+               if (imx_ldb_ch->chno == 0 || dual)
+                       ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH0_24;
+               if (imx_ldb_ch->chno == 1 || dual)
+                       ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH1_24;
                break;
-       default:
-               dev_err(ldb->dev, "unable to config di%d panel format\n",
-                       imx_ldb_ch->chno);
+       case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
                bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+               if (imx_ldb_ch->chno == 0 || dual)
+                       ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH0_24 |
+                                        LDB_BIT_MAP_CH0_JEIDA;
+               if (imx_ldb_ch->chno == 1 || dual)
+                       ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH1_24 |
+                                        LDB_BIT_MAP_CH1_JEIDA;
+               break;
        }
 
        imx_drm_set_bus_format(encoder, bus_format);
@@ -426,25 +443,39 @@ enum {
        LVDS_BIT_MAP_JEIDA
 };
 
-static const char * const imx_ldb_bit_mappings[] = {
-       [LVDS_BIT_MAP_SPWG]  = "spwg",
-       [LVDS_BIT_MAP_JEIDA] = "jeida",
+struct imx_ldb_bit_mapping {
+       u32 bus_format;
+       u32 datawidth;
+       const char * const mapping;
 };
 
-static const int of_get_data_mapping(struct device_node *np)
+static const struct imx_ldb_bit_mapping imx_ldb_bit_mappings[] = {
+       { MEDIA_BUS_FMT_RGB666_1X7X3_SPWG,  18, "spwg" },
+       { MEDIA_BUS_FMT_RGB888_1X7X4_SPWG,  24, "spwg" },
+       { MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA, 24, "jeida" },
+};
+
+static u32 of_get_bus_format(struct device *dev, struct device_node *np)
 {
        const char *bm;
+       u32 datawidth = 0;
        int ret, i;
 
        ret = of_property_read_string(np, "fsl,data-mapping", &bm);
        if (ret < 0)
                return ret;
 
-       for (i = 0; i < ARRAY_SIZE(imx_ldb_bit_mappings); i++)
-               if (!strcasecmp(bm, imx_ldb_bit_mappings[i]))
-                       return i;
+       of_property_read_u32(np, "fsl,data-width", &datawidth);
+
+       for (i = 0; i < ARRAY_SIZE(imx_ldb_bit_mappings); i++) {
+               if (!strcasecmp(bm, imx_ldb_bit_mappings[i].mapping) &&
+                   datawidth == imx_ldb_bit_mappings[i].datawidth)
+                       return imx_ldb_bit_mappings[i].bus_format;
+       }
+
+       dev_err(dev, "invalid data mapping: %d-bit \"%s\"\n", datawidth, bm);
 
-       return -EINVAL;
+       return -ENOENT;
 }
 
 static struct bus_mux imx6q_lvds_mux[2] = {
@@ -481,8 +512,6 @@ static int imx_ldb_bind(struct device *dev, struct device *master, void *data)
        struct device_node *child;
        const u8 *edidp;
        struct imx_ldb *imx_ldb;
-       int datawidth;
-       int mapping;
        int dual;
        int ret;
        int i;
@@ -583,39 +612,20 @@ static int imx_ldb_bind(struct device *dev, struct device *master, void *data)
                                channel->mode_valid = 1;
                }
 
-               ret = of_property_read_u32(child, "fsl,data-width", &datawidth);
-               if (ret)
-                       datawidth = 0;
-               else if (datawidth != 18 && datawidth != 24)
-                       return -EINVAL;
-
-               mapping = of_get_data_mapping(child);
-               switch (mapping) {
-               case LVDS_BIT_MAP_SPWG:
-                       if (datawidth == 24) {
-                               if (i == 0 || dual)
-                                       imx_ldb->ldb_ctrl |=
-                                               LDB_DATA_WIDTH_CH0_24;
-                               if (i == 1 || dual)
-                                       imx_ldb->ldb_ctrl |=
-                                               LDB_DATA_WIDTH_CH1_24;
-                       }
-                       break;
-               case LVDS_BIT_MAP_JEIDA:
-                       if (datawidth == 18) {
-                               dev_err(dev, "JEIDA standard only supported in 24 bit\n");
-                               return -EINVAL;
-                       }
-                       if (i == 0 || dual)
-                               imx_ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH0_24 |
-                                       LDB_BIT_MAP_CH0_JEIDA;
-                       if (i == 1 || dual)
-                               imx_ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH1_24 |
-                                       LDB_BIT_MAP_CH1_JEIDA;
-                       break;
-               default:
-                       dev_err(dev, "data mapping not specified or invalid\n");
-                       return -EINVAL;
+               channel->bus_format = of_get_bus_format(dev, child);
+               if (channel->bus_format == -EINVAL) {
+                       /*
+                        * If no bus format was specified in the device tree,
+                        * we can still get it from the connected panel later.
+                        */
+                       if (channel->panel && channel->panel->funcs &&
+                           channel->panel->funcs->get_modes)
+                               channel->bus_format = 0;
+               }
+               if (channel->bus_format < 0) {
+                       dev_err(dev, "could not determine data mapping: %d\n",
+                               channel->bus_format);
+                       return channel->bus_format;
                }
 
                ret = imx_ldb_register(drm, channel);