With this commit we can modify single values within an array of a dts property.
This is useful if we have for example a pwm-backlight where we want to modifiy the pwm frequency per u-boot script.
The pwm is described in dts like this:
backlight { pwms = <0x0000002b 0x00000000 0x004c4b40>; };
For changing the frequency, here the 3rd parameter, we simply type:
fdt set /backlight pwms <? ? 0x1E8480>;
For doing all this we: - backup the property content into our 'SCRATCHPAD' - only modify the array-cell if the new content doesn't start with '?'
Signed-off-by: Hannes Schmelzer hannes.schmelzer@br-automation.com
---
cmd/fdt.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-)
diff --git a/cmd/fdt.c b/cmd/fdt.c index a21415d..e55102a 100644 --- a/cmd/fdt.c +++ b/cmd/fdt.c @@ -257,6 +257,7 @@ static int do_fdt(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) char *prop; /* property */ int nodeoffset; /* node offset from libfdt */ static char data[SCRATCHPAD]; /* storage for the property */ + const void *ptmp; int len; /* new length of the property */ int ret; /* return value */
@@ -268,13 +269,6 @@ static int do_fdt(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
pathp = argv[2]; prop = argv[3]; - if (argc == 4) { - len = 0; - } else { - ret = fdt_parse_prop(&argv[4], argc - 4, data, &len); - if (ret != 0) - return ret; - }
nodeoffset = fdt_path_offset (working_fdt, pathp); if (nodeoffset < 0) { @@ -286,6 +280,21 @@ static int do_fdt(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) return 1; }
+ if (argc == 4) { + len = 0; + } else { + ptmp = fdt_getprop(working_fdt, nodeoffset, prop, &len); + if (len > SCRATCHPAD) { + printf("prop (%d) doesn't fit in scratchpad!\n", + len); + return 1; + } + memcpy(data, ptmp, len); + ret = fdt_parse_prop(&argv[4], argc - 4, data, &len); + if (ret != 0) + return ret; + } + ret = fdt_setprop(working_fdt, nodeoffset, prop, data, len); if (ret < 0) { printf ("libfdt fdt_setprop(): %s\n", fdt_strerror(ret)); @@ -766,7 +775,11 @@ static int fdt_parse_prop(char * const *newval, int count, char *data, int *len)
cp = newp; tmp = simple_strtoul(cp, &newp, 0); - *(fdt32_t *)data = cpu_to_fdt32(tmp); + if (*cp != '?') + *(fdt32_t *)data = cpu_to_fdt32(tmp); + else + newp++; + data += 4; *len += 4;