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From:   Francesco Dolcini <francesco.dolcini@toradex.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>
Cc:     Francesco Dolcini <francesco.dolcini@toradex.com>,
        linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/2] serial: imx: disable console clocks on unregister
Date:   Wed, 20 Oct 2021 21:26:43 +0200
Message-Id: <20211020192643.476895-3-francesco.dolcini@toradex.com>
In-Reply-To: <20211020192643.476895-1-francesco.dolcini@toradex.com>
References: <20211020192643.476895-1-francesco.dolcini@toradex.com>
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During console setup imx_uart_console_setup() enables clocks, but they
are never disabled when the console is unregistered, this leads to
clk_prepare_enable() being called multiple times without a matching
clk_disable_unprepare() in case of console unregister.

Ensure that clock enable/disable are balanced adding
clk_disable_unprepare() in the console exit callback.

Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
---
 drivers/tty/serial/imx.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 51a9f9423b1a..90f82e6c54e4 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -2124,12 +2124,24 @@ imx_uart_console_setup(struct console *co, char *options)
 	return retval;
 }
 
+static int
+imx_uart_console_exit(struct console *co)
+{
+	struct imx_port *sport = imx_uart_ports[co->index];
+
+	clk_disable_unprepare(sport->clk_per);
+	clk_disable_unprepare(sport->clk_ipg);
+
+	return 0;
+}
+
 static struct uart_driver imx_uart_uart_driver;
 static struct console imx_uart_console = {
 	.name		= DEV_NAME,
 	.write		= imx_uart_console_write,
 	.device		= uart_console_device,
 	.setup		= imx_uart_console_setup,
+	.exit		= imx_uart_console_exit,
 	.flags		= CON_PRINTBUFFER,
 	.index		= -1,
 	.data		= &imx_uart_uart_driver,
-- 
2.25.1