From mboxrd@z Thu Jan 1 00:00:00 1970 From: Claudio Scordino Subject: Re: [PATCH] atmel_serial: RS485: receiving enabled when sending data Date: Tue, 23 Aug 2011 12:06:43 +0200 Message-ID: <4E537BB3.60001@evidence.eu.com> References: <4E492CFF.7040905@pwrnet.de> <20110822211832.GA8023@kroah.com> <4E536536.3030004@evidence.eu.com> <20110823093035.GB19622@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from bishop.asidev.net ([95.141.38.214]:39511 "EHLO bishop.asidev.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750982Ab1HWKGx (ORCPT ); Tue, 23 Aug 2011 06:06:53 -0400 In-Reply-To: <20110823093035.GB19622@n2100.arm.linux.org.uk> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Russell King - ARM Linux Cc: Greg KH , linux-arm-kernel@lists.infradead.org, nicolas.ferre@atmel.com, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Bernhard Roth Il 23/08/2011 11:30, Russell King - ARM Linux ha scritto: > On Tue, Aug 23, 2011 at 10:30:46AM +0200, Claudio Scordino wrote: >> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c >> index af9b781..5f6c745 100644 >> --- a/drivers/tty/serial/atmel_serial.c >> +++ b/drivers/tty/serial/atmel_serial.c >> @@ -339,8 +339,9 @@ static void atmel_stop_tx(struct uart_port *port) >> /* Disable interrupts */ >> UART_PUT_IDR(port, atmel_port->tx_done_mask); >> >> - if (atmel_port->rs485.flags& SER_RS485_ENABLED) >> - atmel_start_rx(port); >> + if ((atmel_port->rs485.flags& SER_RS485_ENABLED)&& >> + !(atmel_port->rs485.flags& SER_RS485_RX_DURING_TX)) >> + atmel_start_rx(port); > > However, this is incorrect formatting. The code following the 'if' ends > up being indented by two tabs. > > This illustrates why the whole idea that tabs should only be used for > indenting is wrong. You end up with either what you have above, or: > > if ((atmel_port->rs485.flags& SER_RS485_ENABLED)&& > !(atmel_port->rs485.flags& SER_RS485_RX_DURING_TX)) > atmel_start_rx(port); > > both of which are dire for readability. The only sane way to do this is > to ignore that stupid "indentation by tabs only" thing and do it as the > kernel code has _always_ been done over the last 19 years: > > if ((atmel_port->rs485.flags& SER_RS485_ENABLED)&& > !(atmel_port->rs485.flags& SER_RS485_RX_DURING_TX)) > atmel_start_rx(port); > > IOW, use spaces to align the wrapped 'if' statement. > >> + if ((atmel_port->rs485.flags& SER_RS485_ENABLED)&& >> + !(atmel_port->rs485.flags& SER_RS485_RX_DURING_TX)) { >> + /* DMA done, stop TX, start RX for RS485 */ >> + atmel_start_rx(port); > > And here it makes it look like there's a missing brace. > I understand. So the right patch should be the following one. Best regards, Claudio atmel_serial: RS485: receiving enabled when sending data By default the atmel_serial driver in RS485 mode disables receiving data until all data in the send buffer has been sent. This flag allows to receive data even whilst sending data. Signed-off-by: Bernhard Roth Signed-off-by: Claudio Scordino --- drivers/tty/serial/atmel_serial.c | 9 ++++++--- include/linux/serial.h | 1 + 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index af9b781..c7232a9 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -339,7 +339,8 @@ static void atmel_stop_tx(struct uart_port *port) /* Disable interrupts */ UART_PUT_IDR(port, atmel_port->tx_done_mask); - if (atmel_port->rs485.flags & SER_RS485_ENABLED) + if ((atmel_port->rs485.flags & SER_RS485_ENABLED) && + !(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX)) atmel_start_rx(port); } @@ -356,7 +357,8 @@ static void atmel_start_tx(struct uart_port *port) really need this.*/ return; - if (atmel_port->rs485.flags & SER_RS485_ENABLED) + if ((atmel_port->rs485.flags & SER_RS485_ENABLED) && + !(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX)) atmel_stop_rx(port); /* re-enable PDC transmit */ @@ -680,7 +682,8 @@ static void atmel_tx_dma(struct uart_port *port) /* Enable interrupts */ UART_PUT_IER(port, atmel_port->tx_done_mask); } else { - if (atmel_port->rs485.flags & SER_RS485_ENABLED) { + if ((atmel_port->rs485.flags & SER_RS485_ENABLED) && + !(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX)) { /* DMA done, stop TX, start RX for RS485 */ atmel_start_rx(port); } diff --git a/include/linux/serial.h b/include/linux/serial.h index ef91406..97ff8e2 100644 --- a/include/linux/serial.h +++ b/include/linux/serial.h @@ -211,6 +211,7 @@ struct serial_rs485 { #define SER_RS485_RTS_ON_SEND (1 << 1) #define SER_RS485_RTS_AFTER_SEND (1 << 2) #define SER_RS485_RTS_BEFORE_SEND (1 << 3) +#define SER_RS485_RX_DURING_TX (1 << 4) __u32 delay_rts_before_send; /* Milliseconds */ __u32 delay_rts_after_send; /* Milliseconds */ __u32 padding[5]; /* Memory is cheap, new structs -- 1.7.1