]> git.kernelconcepts.de Git - karo-tx-uboot.git/blobdiff - board/karo/common/fdt.c
karo: fdt: fix panel-dpi support
[karo-tx-uboot.git] / board / karo / common / fdt.c
index 0a72e6405645da532c00f816ad4b80c3558399a3..909f0ca770a4df3dbb4a6c17e71697732265b372 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * (C) Copyright 2012,2013 Lothar Waßmann <LW@KARO-electronics.de>
+ * (C) Copyright 2012-2014 Lothar Waßmann <LW@KARO-electronics.de>
  *
  * See file CREDITS for list of people who contributed to this
  * project.
@@ -13,7 +13,7 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
-*/
+ */
 
 #include <common.h>
 #include <errno.h>
@@ -48,54 +48,14 @@ static void karo_set_fdtsize(void *fdt)
        setenv_hex("fdtsize", fdt_totalsize(fdt));
 }
 
-static int karo_load_part(const char *part, void *addr, size_t len)
-{
-       int ret;
-       struct mtd_device *dev;
-       struct part_info *part_info;
-       u8 part_num;
-       size_t actual;
-
-       debug("Initializing mtd_parts\n");
-       ret = mtdparts_init();
-       if (ret)
-               return ret;
-
-       debug("Trying to find NAND partition '%s'\n", part);
-       ret = find_dev_and_part(part, &dev, &part_num, &part_info);
-       if (ret) {
-               printf("Failed to find flash partition '%s': %d\n",
-                       part, ret);
-
-               return ret;
-       }
-       debug("Found partition '%s': offset=%08x size=%08x\n",
-               part, part_info->offset, part_info->size);
-       if (part_info->size < len) {
-               printf("Warning: partition '%s' smaller than requested size: %u; truncating data to %u byte\n",
-                       part, len, part_info->size);
-               len = part_info->size;
-       }
-       debug("Reading NAND partition '%s' to %p\n", part, addr);
-       ret = nand_read_skip_bad(&nand_info[0], part_info->offset, &len,
-                               &actual, len, addr);
-       if (ret) {
-               printf("Failed to load partition '%s' to %p\n", part, addr);
-               return ret;
-       }
-       if (actual < len)
-               printf("Read only %u of %u bytes due to bad blocks\n",
-                       actual, len);
-
-       debug("Read %u byte from partition '%s' @ offset %08x\n",
-               len, part, part_info->offset);
-       return 0;
-}
-
 static void *karo_fdt_load_dtb(void)
 {
        int ret;
-       void *fdt = (void *)getenv_ulong("fdtaddr", 16, CONFIG_SYS_FDT_ADDR);
+       void *fdt;
+
+       if (getenv("fdtaddr") == NULL)
+               setenv_hex("fdtaddr", CONFIG_SYS_FDT_ADDR);
+       fdt = (void *)getenv_ulong("fdtaddr", 16, CONFIG_SYS_FDT_ADDR);
 
        if (had_ctrlc()) {
                printf("aborting DTB load\n");
@@ -163,7 +123,7 @@ void karo_fdt_move_fdt(void)
                        fdt_addr, fdt_addr + fdt_totalsize(fdt) - 1);
                memmove((void *)fdt_addr, fdt, fdt_totalsize(fdt));
        }
-       set_working_fdt_addr((void *)fdt_addr);
+       set_working_fdt_addr(fdt_addr);
        gd->fdt_blob = fdt;
        karo_set_fdtsize(fdt);
 }
@@ -207,13 +167,11 @@ static void fdt_disable_tp_node(void *blob, const char *name)
 {
        int offs = fdt_node_offset_by_compatible(blob, -1, name);
 
-       if (offs < 0) {
-               debug("node '%s' not found: %s\n", name, fdt_strerror(offs));
-               return;
+       while (offs >= 0) {
+               debug("Disabling node '%s'\n", name);
+               fdt_set_node_status(blob, offs, FDT_STATUS_DISABLED, 0);
+               offs = fdt_node_offset_by_compatible(blob, offs, name);
        }
-
-       debug("Disabling node '%s'\n", name);
-       fdt_set_node_status(blob, offs, FDT_STATUS_DISABLED, 0);
 }
 
 void karo_fdt_fixup_touchpanel(void *blob, const char *panels[],
@@ -255,7 +213,7 @@ static int karo_fdt_disable_node_phandle(void *blob, const char *parent,
 
        ph = fdt_getprop(blob, off, name, NULL);
        if (ph == NULL) {
-               printf("Failed to find '%s' phandle in node '%s'\n", name,
+               debug("Failed to find '%s' phandle in node '%s'\n", name,
                        fdt_get_name(blob, off, NULL));
                return -FDT_ERR_NOTFOUND;
        }
@@ -269,13 +227,14 @@ static int karo_fdt_disable_node_phandle(void *blob, const char *parent,
        return fdt_set_node_status(blob, off, FDT_STATUS_DISABLED, 0);
 }
 
-void karo_fdt_fixup_usb_otg(void *blob, const char *node, const char *phy)
+void karo_fdt_fixup_usb_otg(void *blob, const char *node, const char *phy,
+                       const char *phy_supply)
 {
        const char *otg_mode = getenv("otg_mode");
        int off;
        int ret;
        int disable_otg = 0;
-       int disable_phy_pins = 1;
+       int disable_phy_pins = 0;
 
        debug("OTG mode is '%s'\n", otg_mode ? otg_mode : "<UNSET>");
 
@@ -285,19 +244,19 @@ void karo_fdt_fixup_usb_otg(void *blob, const char *node, const char *phy)
                return;
        }
 
-       if (otg_mode && (strcmp(otg_mode, "device") == 0 ||
-                               strcmp(otg_mode, "gadget") == 0)) {
+       if (otg_mode && (strcasecmp(otg_mode, "device") == 0 ||
+                               strcasecmp(otg_mode, "gadget") == 0)) {
                debug("Setting dr_mode to 'peripheral'\n");
                ret = fdt_setprop_string(blob, off, "dr_mode", "peripheral");
-       } else if (otg_mode && strcmp(otg_mode, "host") == 0) {
+               disable_phy_pins = 1;
+       } else if (otg_mode && strcasecmp(otg_mode, "host") == 0) {
                debug("Setting dr_mode to 'host'\n");
                ret = fdt_setprop_string(blob, off, "dr_mode", "host");
-               disable_phy_pins = 0;
-       } else if (otg_mode && strcmp(otg_mode, "otg") == 0) {
-               debug("Setting dr_mode to 'host'\n");
+       } else if (otg_mode && strcasecmp(otg_mode, "otg") == 0) {
+               debug("Setting dr_mode to 'otg'\n");
                ret = fdt_setprop_string(blob, off, "dr_mode", "otg");
        } else {
-               if (otg_mode && strcmp(otg_mode, "none") != 0)
+               if (otg_mode && strcasecmp(otg_mode, "none") != 0)
                        printf("Invalid 'otg_mode' setting '%s'; disabling usbotg port\n",
                                otg_mode);
                disable_otg = 1;
@@ -307,20 +266,57 @@ void karo_fdt_fixup_usb_otg(void *blob, const char *node, const char *phy)
        if ((!disable_phy_pins && !disable_otg) || ret)
                goto out;
 
-       ret = karo_fdt_disable_node_phandle(blob, node, "vbus-supply");
-       if (ret)
+       ret = karo_fdt_disable_node_phandle(blob, node, phy_supply);
+       if (ret && ret == -FDT_ERR_NOTFOUND) {
+               const uint32_t *ph;
+
+               ph = fdt_getprop(blob, off, phy, NULL);
+               if (ph == NULL) {
+                       printf("Failed to find '%s' phandle in node '%s'\n",
+                               phy, node);
+                       ret = -FDT_ERR_NOTFOUND;
+                       goto out;
+               }
+               off = fdt_node_offset_by_phandle(blob, fdt32_to_cpu(*ph));
+               if (off < 0) {
+                       printf("Failed to find '%s' node via phandle %04x\n",
+                               phy, fdt32_to_cpu(*ph));
+                       ret = off;
+                       goto out;
+               }
+               ph = fdt_getprop(blob, off, phy_supply, NULL);
+               if (ph == NULL) {
+                       debug("Failed to find '%s' phandle in node '%s'\n",
+                               phy_supply, fdt_get_name(blob, off, NULL));
+                       ret = -FDT_ERR_NOTFOUND;
+                       goto disable_otg;
+               }
+               ret = fdt_node_offset_by_phandle(blob, fdt32_to_cpu(*ph));
+               if (ret > 0) {
+                       debug("Disabling node %s via phandle %s:%s\n",
+                               fdt_get_name(blob, ret, NULL),
+                               fdt_get_name(blob, off, NULL), phy_supply);
+                       ret = fdt_set_node_status(blob, ret,
+                                               FDT_STATUS_DISABLED, 0);
+               }
+       }
+       if (ret && ret != -FDT_ERR_NOTFOUND)
                goto out;
 
+disable_otg:
        if (disable_otg) {
-               debug("Disabling usbphy\n");
+               debug("Disabling '%s'\n", fdt_get_name(blob, off, NULL));
                ret = fdt_set_node_status(blob, off, FDT_STATUS_DISABLED, 0);
-               if (ret)
-                       goto out;
-
-               ret = karo_fdt_disable_node_phandle(blob, node, phy);
+               if (ret > 0)
+                       ret = karo_fdt_disable_node_phandle(blob, node, phy);
+       } else if (disable_phy_pins) {
+               debug("Removing '%s' from node '%s'\n", phy_supply,
+                       fdt_get_name(blob, off, NULL));
+               ret = fdt_delprop(blob, off, phy_supply);
        }
+
 out:
-       if (ret)
+       if (ret && ret != -FDT_ERR_NOTFOUND)
                printf("Failed to update usbotg: %s\n", fdt_strerror(ret));
        else
                debug("node '%s' updated\n", node);
@@ -381,60 +377,78 @@ static inline void karo_fdt_set_lcd_pins(void *blob, const char *name)
 
 void karo_fdt_fixup_flexcan(void *blob, int xcvr_present)
 {
+       int ret;
        const char *xcvr_status = "disabled";
+       const char *otg_mode = getenv("otg_mode");
 
-#ifndef CONFIG_SYS_LVDS_IF
        if (xcvr_present) {
                if (karo_fdt_flexcan_enabled(blob)) {
-                       karo_fdt_set_lcd_pins(blob, "lcdif_23bit_pins_a");
-                       xcvr_status = "okay";
-               } else {
+                       if (!is_lvds()) {
+                               debug("Changing LCD to use 23bits only\n");
+                               karo_fdt_set_lcd_pins(blob, "lcdif-23bit-pins-a");
+                               /* handle legacy alias name */
+                               karo_fdt_set_lcd_pins(blob, "lcdif_23bit_pins_a");
+                               xcvr_status = NULL;
+                       }
+               } else if (!is_lvds()) {
+                       debug("Changing LCD to use 24bits\n");
+                       karo_fdt_set_lcd_pins(blob, "lcdif-24bit-pins-a");
+                       /* handle legacy alias name */
                        karo_fdt_set_lcd_pins(blob, "lcdif_24bit_pins_a");
                }
        } else {
-               const char *otg_mode = getenv("otg_mode");
+               int off = fdt_path_offset(blob, "can0");
+
+               if (off >= 0)
+                       fdt_delprop(blob, off, "xceiver-supply");
+               off = fdt_path_offset(blob, "can1");
+               if (off >= 0)
+                       fdt_delprop(blob, off, "xceiver-supply");
+               if (!is_lvds()) {
+                       karo_fdt_set_lcd_pins(blob, "lcdif-24bit-pins-a");
+                       /* handle legacy alias name */
+                       karo_fdt_set_lcd_pins(blob, "lcdif_24bit_pins_a");
+               }
+       }
 
-               if (otg_mode && (strcmp(otg_mode, "host") == 0))
-                       karo_fdt_enable_node(blob, "can1", 0);
+       if (otg_mode && strcasecmp(otg_mode, "host") == 0)
+               karo_fdt_enable_node(blob, "can1", 0);
 
-               karo_fdt_set_lcd_pins(blob, "lcdif_24bit_pins_a");
+       if (xcvr_status) {
+               debug("Disabling CAN XCVR\n");
+               ret = fdt_find_and_setprop(blob, "reg-can-xcvr", "status",
+                                       xcvr_status, strlen(xcvr_status) + 1, 1);
+               if (ret == -FDT_ERR_NOTFOUND || ret == -FDT_ERR_BADPATH)
+                       ret = fdt_find_and_setprop(blob, "reg_can_xcvr", "status",
+                                                  xcvr_status, strlen(xcvr_status) + 1, 1);
+               if (ret && ret != -FDT_ERR_NOTFOUND && ret != -FDT_ERR_BADPATH)
+                       printf("Failed to disable CAN transceiver switch: %s\n",
+                               fdt_strerror(ret));
        }
-#endif
-       fdt_find_and_setprop(blob, "reg_can_xcvr", "status",
-                       xcvr_status, strlen(xcvr_status) + 1, 1);
 }
 
-void karo_fdt_del_prop(void *blob, const char *compat, phys_addr_t offs,
-                       const char *prop)
+void karo_fdt_del_prop(void *blob, const char *compat, u32 offs,
+                       const char *propname)
 {
-       int ret;
-       int offset;
-       const uint32_t *phandle;
-       uint32_t ph = 0;
-
-       offset = fdt_node_offset_by_compat_reg(blob, compat, offs);
-       if (offset <= 0)
-               return;
-
-       phandle = fdt_getprop(blob, offset, prop, NULL);
-       if (phandle) {
-               ph = fdt32_to_cpu(*phandle);
-       }
+       int offset = -1;
+       const fdt32_t *reg = NULL;
 
-       debug("Removing property '%s' from node %s@%08lx\n", prop, compat, offs);
-       ret = fdt_delprop(blob, offset, prop);
-       if (ret == 0)
-               karo_set_fdtsize(blob);
+       while (1) {
+               offset = fdt_node_offset_by_compatible(blob, offset, compat);
+               if (offset <= 0)
+                       return;
 
-       if (!ph)
-               return;
+               reg = fdt_getprop(blob, offset, "reg", NULL);
+               if (reg == NULL)
+                       return;
 
-       offset = fdt_node_offset_by_phandle(blob, ph);
-       if (offset <= 0)
-               return;
+               if (fdt32_to_cpu(*reg) == offs)
+                       break;
+       }
+       debug("Removing property '%s' from node %s@%x\n",
+               propname, compat, offs);
+       fdt_delprop(blob, offset, propname);
 
-       debug("Removing node @ %08x\n", offset);
-       fdt_del_node(blob, offset);
        karo_set_fdtsize(blob);
 }
 
@@ -494,7 +508,7 @@ static int fdt_init_fb_mode(const void *blob, int off, struct fb_videomode *fb_m
 
        prop = fdt_getprop(blob, off, "pixelclk-active", NULL);
        if (prop)
-               fb_mode->sync |= *prop ? 0 : FB_SYNC_CLK_LAT_FALL;
+               fb_mode->sync |= *prop ? FB_SYNC_CLK_LAT_FALL : 0;
 
        return 0;
 }
@@ -549,15 +563,27 @@ static int karo_fdt_find_video_timings(void *blob)
        return off;
 }
 
-int karo_fdt_get_fb_mode(void *blob, const char *name, struct fb_videomode *fb_mode)
+static int karo_fdt_check_panel_name(const char *pn, const char *name, int len)
 {
-       int off = karo_fdt_find_video_timings(blob);
+       const char *endp = pn + len;
 
-       if (off < 0)
-               return off;
+       if (len < 0)
+               return 0;
+       while (pn < endp) {
+               if (strcasecmp(pn, name) == 0)
+                       return 1;
+               pn += strlen(pn) + 1;
+       }
+       return 0;
+}
+
+static int karo_fdt_find_panel(const void *blob, int off, const char *name)
+{
+       debug("Searching panel '%s'\n", name);
        while (off > 0) {
-               const char *n, *endp;
-               int len, d = 1;
+               const char *pn;
+               int d = 1;
+               int len;
 
                off = fdt_next_node(blob, off, &d);
                if (off < 0)
@@ -569,31 +595,31 @@ int karo_fdt_get_fb_mode(void *blob, const char *name, struct fb_videomode *fb_m
                                fdt_get_name(blob, off, NULL), d);
                        continue;
                }
-               debug("parsing subnode @ %04x %s depth %d\n", off,
-                       fdt_get_name(blob, off, NULL), d);
-
-               n = fdt_getprop(blob, off, "panel-name", &len);
-               if (!n) {
-                       n = fdt_get_name(blob, off, NULL);
-                       if (strcasecmp(n, name) == 0) {
-                               break;
-                       }
-               } else {
-                       int found = 0;
-
-                       for (endp = n + len; n < endp; n += strlen(n) + 1) {
-                               debug("Checking panel-name '%s'\n", n);
-                               if (strcasecmp(n, name) == 0) {
-                                       debug("Using node %s @ %04x\n",
-                                               fdt_get_name(blob, off, NULL), off);
-                                       found = 1;
-                                       break;
-                               }
-                       }
-                       if (found)
-                               break;
-               }
+
+               pn = fdt_get_name(blob, off, NULL);
+               debug("Checking node name '%s'\n", pn);
+               if (strcasecmp(pn, name) == 0)
+                       break;
+               pn = fdt_getprop(blob, off, "u-boot,panel-name", &len);
+               if (!pn)
+                       continue;
+               if (karo_fdt_check_panel_name(pn, name, len))
+                       break;
        }
+       if (off > 0)
+               debug("Found LCD panel: '%s' @ off %03x\n",
+                     fdt_get_name(blob, off, NULL), off);
+       return off;
+}
+
+int karo_fdt_get_fb_mode(void *blob, const char *name,
+                        struct fb_videomode *fb_mode)
+{
+       int off = karo_fdt_find_video_timings(blob);
+
+       if (off < 0)
+               return off;
+       off = karo_fdt_find_panel(blob, off, name);
        if (off > 0) {
                return fdt_init_fb_mode(blob, off, fb_mode);
        }
@@ -696,21 +722,107 @@ out:
        return ret;
 }
 
-int karo_fdt_update_fb_mode(void *blob, const char *name)
+static const char *karo_panel_timing_props[] = {
+       "clock-frequency",
+       "hactive",
+       "vactive",
+       "hback-porch",
+       "hsync-len",
+       "hfront-porch",
+       "vback-porch",
+       "vsync-len",
+       "vfront-porch",
+       "hsync-active",
+       "vsync-active",
+       "de-active",
+       "pixelclk-active",
+};
+
+static int karo_fixup_panel_timing(void *fdt, int dest, int src)
+{
+       size_t i;
+
+       for (i = 0; i < ARRAY_SIZE(karo_panel_timing_props); i++) {
+               const char *name = karo_panel_timing_props[i];
+               int len;
+               int ret;
+               const void *val;
+               bool restart;
+
+               val = fdt_getprop(fdt, src, name, &len);
+               if (!val) {
+                       if (fdt_getprop(fdt, dest, name, NULL)) {
+                               printf("Removing '%s' from '%s'\n", name,
+                                      fdt_get_name(fdt, dest, NULL));
+                               fdt_delprop(fdt, dest, name);
+                               return -EAGAIN;
+                       }
+                       continue;
+               }
+               if (len != sizeof(u32)) {
+                       printf("Property '%s' has invalid size %u\n",
+                              name, len);
+                       return -EINVAL;
+               }
+               debug("setting '%s' to <0x%08x>\n", name, be32_to_cpup(val));
+
+               restart = !fdt_getprop(fdt, dest, name, &len);
+               restart |= len != sizeof(u32);
+               /* DTB offsets will change when adding a new property */
+               if (restart) {
+                       ret = fdt_increase_size(fdt, len);
+                       if (ret) {
+                               printf("Failed to increase FDT size by %u: %s\n", len,
+                                      fdt_strerror(ret));
+                               return -ENOMEM;
+                       }
+                       printf("Adding new property '%s' to '%s'\n",
+                              name, fdt_get_name(fdt, dest, NULL));
+               }
+               ret = fdt_setprop_u32(fdt, dest, name, be32_to_cpup(val));
+               if (ret) {
+                       printf("Failed to set %s property: %s\n", name,
+                              fdt_strerror(ret));
+                       return -EINVAL;
+               }
+               if (restart)
+                       return -EAGAIN;
+       }
+       return 0;
+}
+
+int karo_fdt_update_fb_mode(void *blob, const char *name,
+                           const char *panel_name)
 {
+       int ret;
        int off = fdt_path_offset(blob, "display");
+       int dt_node;
+       int panel_off = -1;
        const char *subnode = "display-timings";
+       size_t i = 0;
 
-       if (off < 0)
+       if (panel_name)
+               panel_off = fdt_path_offset(blob, panel_name);
+
+       if (off < 0 && panel_off < 0)
                return off;
 
        if (name == NULL) {
-               int ret;
-
                debug("Disabling node '%s' at %03x\n",
                        fdt_get_name(blob, off, NULL), off);
                ret = fdt_set_node_status(blob, off, FDT_STATUS_DISABLED, 0);
-               return ret;
+               if (ret)
+                       printf("Failed to disable node '%s': %s\n",
+                              fdt_get_name(blob, off, NULL),
+                              fdt_strerror(ret));
+               if (!panel_name)
+                       return ret;
+
+               panel_off = fdt_path_offset(blob, panel_name);
+               if (panel_off < 0)
+                       return 0;
+               return fdt_set_node_status(blob, panel_off,
+                                          FDT_STATUS_DISABLED, 0);
        }
 
        off = fdt_subnode_offset(blob, off, subnode);
@@ -719,50 +831,73 @@ int karo_fdt_update_fb_mode(void *blob, const char *name)
                        fdt_strerror(off));
                return off;
        }
-       while (off > 0) {
-               const char *n, *endp;
-               int len, d = 1;
-
-               off = fdt_next_node(blob, off, &d);
-               if (off < 0)
-                       return off;
-               if (d < 1)
-                       return -EINVAL;
-               if (d > 2) {
-                       debug("Skipping node @ %04x %s depth %d\n", off,
-                               fdt_get_name(blob, off, NULL), d);
-                       continue;
+       off = karo_fdt_find_panel(blob, off, name);
+       if (off > 0)
+               ret = fdt_update_native_fb_mode(blob, off);
+       else
+               ret = 0;
+       if (!panel_name)
+               return ret;
+ restart:
+       dt_node = fdt_path_offset(blob, "display/display-timings");
+       off = karo_fdt_find_panel(blob, dt_node, name);
+       panel_off = fdt_path_offset(blob, panel_name);
+       if (panel_off > 0) {
+               int node = fdt_subnode_offset(blob, dt_node, name);
+
+               if (node < 0) {
+                       printf("Warning: No '%s' subnode found in 'display-timings'\n",
+                              name);
+                       return -ENOENT;
                }
-               debug("parsing subnode @ %04x %s depth %d\n", off,
-                       fdt_get_name(blob, off, NULL), d);
-
-               n = fdt_getprop(blob, off, "panel-name", &len);
-               if (!n) {
-                       n = fdt_get_name(blob, off, NULL);
-                       if (strcasecmp(n, name) == 0) {
-                               break;
+               if (fdt_node_check_compatible(blob, panel_off, "panel-dpi") == 0) {
+                       int timing_node = fdt_subnode_offset(blob, panel_off,
+                                                            "panel-timing");
+
+                       if (timing_node < 0) {
+                               printf("Warning: No 'panel-timing' subnode found\n");
+                               return -ENOENT;
                        }
-               } else {
-                       int found = 0;
-
-                       for (endp = n + len; n < endp; n += strlen(n) + 1) {
-                               debug("Checking panel-name '%s'\n", n);
-                               if (strcasecmp(n, name) == 0) {
-                                       debug("Using node %s @ %04x\n",
-                                               fdt_get_name(blob, off, NULL), off);
-                                       found = 1;
-                                       break;
-                               }
+
+                       if (i == 0)
+                               printf("Copying video timing from %s\n", name);
+                       ret = karo_fixup_panel_timing(blob,
+                                                     timing_node,
+                                                     node);
+                       if (ret == -EAGAIN) {
+                               if (i++ > ARRAY_SIZE(karo_panel_timing_props))
+                                       return -EINVAL;
+                               goto restart;
                        }
-                       if (found)
-                               break;
+               } else {
+                       char *pn;
+
+                       name = fdt_getprop(blob, off, "u-boot,panel-name",
+                                          NULL);
+                       if (!name)
+                               return 0;
+
+                       pn = strdup(name);
+                       if (!pn)
+                               return -ENOMEM;
+                       debug("%s@%d: Updating 'compatible' property of '%s' from '%s' to '%s'\n",
+                             __func__, __LINE__, fdt_get_name(blob, panel_off, NULL),
+                             (char *)fdt_getprop(blob, panel_off, "compatible", NULL),
+                             pn);
+
+                       ret = fdt_setprop_string(blob, panel_off, "compatible",
+                                                pn);
+                       if (ret)
+                               printf("Failed to set 'compatible' property of node '%s': %s\n",
+                                      fdt_get_name(blob, panel_off, NULL),
+                                      fdt_strerror(off));
+                       free(pn);
                }
        }
-       if (off > 0)
-               return fdt_update_native_fb_mode(blob, off);
-       return off;
+       return ret;
 }
 
+#ifdef CONFIG_SYS_LVDS_IF
 int karo_fdt_get_lcd_bus_width(const void *blob, int default_width)
 {
        int off = fdt_path_offset(blob, "display");
@@ -815,3 +950,41 @@ u8 karo_fdt_get_lvds_channels(const void *blob)
        }
        return lvds_chan_mask;
 }
+#endif
+
+int karo_fdt_get_backlight_polarity(const void *blob)
+{
+#ifdef CONFIG_SYS_LVDS_IF
+       const char *backlight_node = "/backlight0";
+#else
+       const char *backlight_node = "/backlight";
+#endif
+       int off = fdt_path_offset(blob, "backlight"); /* first try alias */
+       const struct fdt_property *prop;
+       int len;
+
+       if (off < 0) {
+               /*
+                * if no 'backlight' alias exists try finding '/backlight0'
+                * or '/backlight' depending on LVDS or not
+                */
+               off = fdt_path_offset(blob, backlight_node);
+               if (off < 0) {
+                       printf("%s node not found in DT\n", backlight_node);
+                       return off;
+               }
+       }
+
+       prop = fdt_get_property(blob, off, "pwms", &len);
+       if (!prop)
+               printf("'pwms' property not found\n");
+       else
+               debug("'pwms' property has len %d\n", len);
+
+       len /= sizeof(u32);
+       if (prop && len > 3) {
+               const u32 *data = (const u32 *)prop->data;
+               return fdt32_to_cpu(data[3]) == 0;
+       }
+       return 0;
+}