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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Lukas Wunner <lukas@wunner.de>,
        Martin Sperl <kernel@martin.sperl.org>,
        Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Subject: [PATCH 4.9 12/68] serial: 8250_bcm2835aux: Fix line mismatch on driver unbind
Date:   Mon,  3 Feb 2020 16:19:08 +0000
Message-Id: <20200203161906.890593314@linuxfoundation.org>
In-Reply-To: <20200203161904.705434837@linuxfoundation.org>
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From: Lukas Wunner <lukas@wunner.de>

commit dc76697d7e933d5e299116f219c890568785ea15 upstream.

Unbinding the bcm2835aux UART driver raises the following error if the
maximum number of 8250 UARTs is set to 1 (via the 8250.nr_uarts module
parameter or CONFIG_SERIAL_8250_RUNTIME_UARTS):

(NULL device *): Removing wrong port: a6f80333 != fa20408b

That's because bcm2835aux_serial_probe() retrieves UART line number 1
from the devicetree and stores it in data->uart.port.line, while
serial8250_register_8250_port() instead uses UART line number 0,
which is stored in data->line.

On driver unbind, bcm2835aux_serial_remove() uses data->uart.port.line,
which contains the wrong number.  Fix it.

The issue does not occur if the maximum number of 8250 UARTs is >= 2.

Fixes: bdc5f3009580 ("serial: bcm2835: add driver for bcm2835-aux-uart")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v4.6+
Cc: Martin Sperl <kernel@martin.sperl.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/912ccf553c5258135c6d7e8f404a101ef320f0f4.1579175223.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/tty/serial/8250/8250_bcm2835aux.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/tty/serial/8250/8250_bcm2835aux.c
+++ b/drivers/tty/serial/8250/8250_bcm2835aux.c
@@ -119,7 +119,7 @@ static int bcm2835aux_serial_remove(stru
 {
 	struct bcm2835aux_data *data = platform_get_drvdata(pdev);
 
-	serial8250_unregister_port(data->uart.port.line);
+	serial8250_unregister_port(data->line);
 	clk_disable_unprepare(data->clk);
 
 	return 0;