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Tue, 23 Nov 2021 05:13:54 -0800 From: Shubhrajyoti Datta To: CC: , , , , Shubhrajyoti Datta Subject: [PATCH v2] serial-uartlite: Remove an un-necessary read of control register Date: Tue, 23 Nov 2021 18:43:48 +0530 Message-ID: <20211123131348.26295-1-shubhrajyoti.datta@xilinx.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 6778d44a-aeb8-4adf-ad7d-08d9ae831dfe X-MS-TrafficTypeDiagnostic: CH2PR02MB6328: X-Microsoft-Antispam-PRVS: X-Auto-Response-Suppress: DR, RN, NRN, OOF, AutoReply X-MS-Oob-TLC-OOBClassifiers: OLM:2512; X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:149.199.62.198;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:xsj-pvapexch01.xlnx.xilinx.com;PTR:unknown-62-198.xilinx.com;CAT:NONE;SFS:(46966006)(36840700001)(36756003)(47076005)(8936002)(107886003)(336012)(83380400001)(7696005)(426003)(6666004)(82310400004)(6916009)(44832011)(1076003)(508600001)(54906003)(356005)(7636003)(70586007)(186003)(8676002)(36860700001)(70206006)(316002)(2906002)(36906005)(966005)(2616005)(9786002)(4326008)(5660300002)(26005)(102446001);DIR:OUT;SFP:1101; X-OriginatorOrg: xilinx.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Nov 2021 13:14:01.5335 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 6778d44a-aeb8-4adf-ad7d-08d9ae831dfe X-MS-Exchange-CrossTenant-Id: 657af505-d5df-48d0-8300-c31994686c5c X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=657af505-d5df-48d0-8300-c31994686c5c;Ip=[149.199.62.198];Helo=[xsj-pvapexch01.xlnx.xilinx.com] X-MS-Exchange-CrossTenant-AuthSource: BN1NAM02FT027.eop-nam02.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR02MB6328 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org The control register is a writeonly register that's why reading it doesn't make any sense. The manual states "This is a write-only register. Issuing a read request to the control register generates the read acknowledgment with zero data." Signed-off-by: Shubhrajyoti Datta --- v2: Update the description https://www.xilinx.com/support/documentation/ip_documentation/axi_uartlite/v2_0/pg142-axi-uartlite.pdf drivers/tty/serial/uartlite.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c index dfc1ba4e1572..0df471eddb0e 100644 --- a/drivers/tty/serial/uartlite.c +++ b/drivers/tty/serial/uartlite.c @@ -297,7 +297,6 @@ static void ulite_shutdown(struct uart_port *port) struct uartlite_data *pdata = port->private_data; uart_out32(0, ULITE_CONTROL, port); - uart_in32(ULITE_CONTROL, port); /* dummy */ free_irq(port->irq, port); clk_disable(pdata->clk); } @@ -368,7 +367,6 @@ static int ulite_request_port(struct uart_port *port) } pdata->reg_ops = &uartlite_be; - ret = uart_in32(ULITE_CONTROL, port); uart_out32(ULITE_CONTROL_RST_TX, ULITE_CONTROL, port); ret = uart_in32(ULITE_STATUS, port); /* Endianess detection */ -- 2.17.1