Re: [PATCH v2] vsprintf: Add %p extension "%pOF" for device tree

From: Randy Dunlap
Date: Thu Jun 22 2017 - 18:44:22 EST


On 06/22/2017 01:44 PM, Rob Herring wrote:
> From: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
>
> 90% of the usage of device node's full_name is printing it out in a
> kernel message. However, storing the full path for every node is
> wasteful and redundant. With a custom format specifier, we can generate
> the full path at run-time and eventually remove the full path from every
> node.
>
> For instance typical use is:
> pr_info("Frobbing node %s\n", node->full_name);
>
> Which can be written now as:
> pr_info("Frobbing node %pOF\n", node);


isn't OF for flags -- and Of for full name?
Typo or a change in the last 2 years?

> More fine-grained control of formatting includes printing the name,
> flags, path-spec name and others, explained in the documentation entry.
>
> Originally written by Pantelis, but pretty much rewrote the core
> function using existing string/number functions. The 2 passes were
> unnecessary and have been removed. Also, updated the checkpatch.pl
> check. The unittest code was written by Grant Likely.
>
> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
> Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
> ---
> I missed some comments and changes Grant had done and incorporated them.
>
> v2:
> - Change subject
> - Rewrite device_node_gen_full_name() to avoid recursion.
> - Avoid using sprintf.
> - Add unittests Grant L. wrote.
> - Drop ref count printing (from discussion 2 years ago).
> - Remove fmtp local var.
>
>
> Documentation/printk-formats.txt | 30 ++++++
> drivers/of/unittest-data/tests-platform.dtsi | 4 +-
> drivers/of/unittest.c | 58 +++++++++++
> lib/vsprintf.c | 140 +++++++++++++++++++++++++++
> scripts/checkpatch.pl | 2 +-
> 5 files changed, 232 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
> index 5962949944fd..c7af38188f12 100644
> --- a/Documentation/printk-formats.txt
> +++ b/Documentation/printk-formats.txt
> @@ -275,6 +275,36 @@ struct va_format:
>
> Passed by reference.
>
> +Device tree nodes:
> +
> + %pOn[fnpPcCF]
> +
> + For printing device tree nodes. The optional arguments are:
> + f device node full_name
> + n device node name
> + p device node phandle
> + P device node path spec (name + @unit)
> + F device node flags
> + c major compatible string
> + C full compatible string
> + Without any arguments prints full_name (same as %pOFf)
> + The separator when using multiple arguments is ':'
> +
> + Examples:
> +
> + %pOn /foo/bar@0 - Node full name
> + %pOnf /foo/bar@0 - Same as above
> + %pOnfp /foo/bar@0:10 - Node full name + phandle
> + %pOnfcF /foo/bar@0:foo,device:--P- - Node full name +
> + major compatible string +
> + node flags
> + D - dynamic
> + d - detached
> + P - Populated
> + B - Populated bus
> +
> + Passed by reference.
> +
> struct clk:
>
> %pC pll1

--
~Randy