Commit d4f64187 authored Dec 09, 2014 by Cyrille Pitchen Committed by Greg Kroah-Hartman Jan 09, 2015

tty/serial: at91: enable peripheral clock before accessing I/O registers



atmel_serial_probe() calls atmel_init_port(). In turn, atmel_init_port() calls
clk_disable_unprepare() to disable the peripheral clock before returning.

Later atmel_serial_probe() accesses some I/O registers such as the Mode and
Control registers for RS485 support then the Name and Version registers, through a call to
atmel_get_ip_name(), but at that moment the peripheral clock was still
disabled.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: <stable@vger.kernel.org> # 3.12+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 485819b5

drivers/tty/serial/atmel_serial.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -2596,6 +2596,12 @@ static int atmel_serial_probe(struct platform_device *pdev)
		device_init_wakeup(&pdev->dev, 1);
		platform_set_drvdata(pdev, port);

		/*
		* The peripheral clock has been disabled by atmel_init_port():
		* enable it before accessing I/O registers
		*/
		clk_prepare_enable(port->clk);

		if (rs485_enabled) {
		UART_PUT_MR(&port->uart, ATMEL_US_USMODE_NORMAL);
		UART_PUT_CR(&port->uart, ATMEL_US_RTSEN);
		@@ -2606,6 +2612,12 @@ static int atmel_serial_probe(struct platform_device *pdev)
		*/
		atmel_get_ip_name(&port->uart);

		/*
		* The peripheral clock can now safely be disabled till the port
		* is used
		*/
		clk_disable_unprepare(port->clk);

		return 0;

		err_add_port: