| Message ID | 1496149544-32348-1-git-send-email-hannes.schmelzer@br-automation.com |
|---|---|
| State | Accepted |
| Commit | 9620d87259572ef21f0df60988d9a932ca673779 |
| Delegated to: | Simon Glass |
| Headers | show |
On 30 May 2017 at 07:05, Hannes Schmelzer <hannes.schmelzer@br-automation.com> wrote: > 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(-) Reviewed-by: Simon Glass <sjg@chromium.org> I imagine this would have to be done before setting 'stdout' to 'vidconsole' so that the PWM is not inited before this script runs.
sjg@google.com schrieb am 01.06.2017 05:11:57: > <hannes.schmelzer@br-automation.com> wrote: > > 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(-) > > Reviewed-by: Simon Glass <sjg@chromium.org> > > I imagine this would have to be done before setting 'stdout' to > 'vidconsole' so that the PWM is not inited before this script runs. Yes, if lcd output is used already in u-boot this is correct. For my case i don't have any output in u-boot, but later on within linux environment. But setting some pwm frequency is only one example for using this, every other array-property can also be modified with this. cheers, Hannes
sjg@google.com schrieb am 01.06.2017 05:11:57: > <hannes.schmelzer@br-automation.com> wrote: > > 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(-) > > Reviewed-by: Simon Glass <sjg@chromium.org> > > I imagine this would have to be done before setting 'stdout' to > 'vidconsole' so that the PWM is not inited before this script runs. Yes, if lcd output is used already in u-boot this is correct. For my case i don't have any output in u-boot, but later on within linux environment. But setting some pwm frequency is only one example for using this, every other array-property can also be modified with this. cheers, Hannes Applied to u-boot-dm, thanks!
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;
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(-)