From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964795AbbCDGma (ORCPT ); Wed, 4 Mar 2015 01:42:30 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:43738 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933608AbbCDGVQ (ORCPT ); Wed, 4 Mar 2015 01:21:16 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Cyrille Pitchen , Nicolas Ferre Subject: [PATCH 3.19 115/175] tty/serial: at91: enable peripheral clock before accessing I/O registers Date: Tue, 3 Mar 2015 22:14:53 -0800 Message-Id: <20150304061044.978626776@linuxfoundation.org> X-Mailer: git-send-email 2.3.1 In-Reply-To: <20150304061026.134125919@linuxfoundation.org> References: <20150304061026.134125919@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cyrille Pitchen commit d4f641876a68d1961e30c202709cc2d484f69f6f upstream. 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 Acked-by: Nicolas Ferre Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/atmel_serial.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -2596,6 +2596,12 @@ static int atmel_serial_probe(struct pla 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 pla */ 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: