linux-kernel - [PATCH 0/2] vsprintf: remove redundant %pCn format specifier

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Message-Id: <20250307-vsprintf-pcn-v1-0-df0b2ccf610f@bootlin.com>
Date: Fri, 07 Mar 2025 12:19:06 +0100
From: Luca Ceresoli <luca.ceresoli@...tlin.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>, 
 Daniel Lezcano <daniel.lezcano@...aro.org>, Zhang Rui <rui.zhang@...el.com>, 
 Lukasz Luba <lukasz.luba@....com>, 
 Florian Fainelli <florian.fainelli@...adcom.com>, 
 Ray Jui <rjui@...adcom.com>, Scott Branden <sbranden@...adcom.com>, 
 Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>, 
 Petr Mladek <pmladek@...e.com>, Steven Rostedt <rostedt@...dmis.org>, 
 Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, 
 Rasmus Villemoes <linux@...musvillemoes.dk>, 
 Sergey Senozhatsky <senozhatsky@...omium.org>, 
 Jonathan Corbet <corbet@....net>, Andrew Morton <akpm@...ux-foundation.org>
Cc: Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 Michael Turquette <mturquette@...libre.com>, 
 Stephen Boyd <sboyd@...nel.org>, 
 Geert Uytterhoeven <geert+renesas@...der.be>, Liu Ying <victor.liu@....com>, 
 linux-clk@...r.kernel.org, linux-pm@...r.kernel.org, 
 linux-rpi-kernel@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org, 
 Luca Ceresoli <luca.ceresoli@...tlin.com>
Subject: [PATCH 0/2] vsprintf: remove redundant %pCn format specifier

There are two printk format specifiers for clocks: %pC and %pCn, and they
print exactly the same string. The reason for having two is not totally
clear (see discussion in patch 2), but there seem to be no advantage in
having two instead of one.

Definitely having two without properly documenting they do the same creates
misunderstandings [0].

Since %pCn is used in a single place, replace it with %pC and remove %pCn
to simplify such format specifiers implementation and avoid
misunderstandings.

[0] https://lore.kernel.org/dri-devel/71c44221-b18b-4928-8faf-00893ec4a109@nxp.com/

Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>
---
Luca Ceresoli (2):
      thermal: bcm2835: use %pC instead of %pCn
      vsprintf: remove redundant and unused %pCn format specifier

 Documentation/core-api/printk-formats.rst  |  3 +--
 drivers/thermal/broadcom/bcm2835_thermal.c |  2 +-
 lib/vsprintf.c                             | 10 ++--------
 3 files changed, 4 insertions(+), 11 deletions(-)
---
base-commit: 7eb172143d5508b4da468ed59ee857c6e5e01da6
change-id: 20250307-vsprintf-pcn-8a43e3b0d43e

Best regards,
-- 
Luca Ceresoli <luca.ceresoli@...tlin.com>