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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>
This commit is contained in:
Cyrille Pitchen 2014-12-09 14:31:33 +01:00 committed by Greg Kroah-Hartman
parent 485819b5b9
commit d4f641876a
1 changed files with 12 additions and 0 deletions
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12
drivers/tty/serial/atmel_serial.c
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@ -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: