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[2a02:3100:ae93:f301:cdd9:d5ea:80d:9131]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-496b499cc49sm20754015e9.9.2026.07.24.14.37.14 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 24 Jul 2026 14:37:15 -0700 (PDT) From: Karl Mehltretter To: Russell King , Greg Kroah-Hartman , Jiri Slaby Cc: Karl Mehltretter , linux-arm-kernel@lists.infradead.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Sebastian Andrzej Siewior , John Ogness , Petr Mladek , Steven Rostedt , Clark Williams , Toshiyuki Sato Subject: [PATCH v2 1/2] serial: amba-pl011: unprepare console clock on unregister Date: Fri, 24 Jul 2026 23:33:47 +0200 Message-Id: <20260724213348.77418-2-kmehltretter@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20260724213348.77418-1-kmehltretter@gmail.com> References: <20260724213348.77418-1-kmehltretter@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit pl011_console_setup() calls clk_prepare() on the UART clock, but the console provides no matching teardown, so the clock is never unprepared when the console is unregistered -- via the sysfs "console" attribute or a driver unbind. Each re-registration prepares the clock again, leaking one prepare reference per cycle. Even where preparing the clock has no hardware effect, the stale reference leaves the clock framework's prepare count unbalanced. For providers with prepare/unprepare operations or runtime-PM integration, it may also retain resources after the console is unregistered. Add a console .exit() callback that clk_unprepare()s the clock, balancing the clk_prepare() in pl011_console_setup(). Fixes: 4b4851c65d92 ("clk: amba-pl011: convert to clk_prepare()/clk_unprepare()") Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter --- drivers/tty/serial/amba-pl011.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 8ed91e1da22b..1aa43994a3cd 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -2552,6 +2552,15 @@ static int pl011_console_setup(struct console *co, char *options) return uart_set_options(&uap->port, co, baud, parity, bits, flow); } +static int pl011_console_exit(struct console *co) +{ + struct uart_amba_port *uap = amba_ports[co->index]; + + clk_unprepare(uap->clk); + + return 0; +} + /** * pl011_console_match - non-standard console matching * @co: registering console @@ -2705,6 +2714,7 @@ static struct console amba_console = { .name = "ttyAMA", .device = uart_console_device, .setup = pl011_console_setup, + .exit = pl011_console_exit, .match = pl011_console_match, .write_atomic = pl011_console_write_atomic, .write_thread = pl011_console_write_thread, -- 2.53.0