From: Bernhard Roth <br@pwrnet.de> To: nicolas.ferre@atmel.com Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, claudio@evidence.eu.com Subject: [PATCH] atmel_serial: RS485: receiving enabled when sending data Date: Mon, 15 Aug 2011 16:28:15 +0200 [thread overview] Message-ID: <4E492CFF.7040905@pwrnet.de> (raw) Hello! 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. This is very useful to - check if the data has been sent correctly over the RS485 bus - assure that no collision happened - check for short circuits/termination issues on the RS485 bus Usually this functionality is realized by hardware, wether controlling the RX-Enable pin of the RS485 transceiver with RTS (driver control signal) or pulling it LOW permanently. The present atmel_serial driver makes this impossible, thus requiring following patch. Usage example: struct serial_rs485 rs485; memset(&rs485, 0, sizeof(rs485)); rs485.flags = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX; ioctl(fd, TIOCSRS485, &rs485); 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 <br@pwrnet.de> Signed-off-by: Claudio Scordino <claudio@evidence.eu.com> --- drivers/tty/serial/atmel_serial.c | 17 ++++++++++------- include/linux/serial.h | 1 + 2 files changed, 11 insertions(+), 7 deletions(-) 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); } /* @@ -356,8 +357,9 @@ static void atmel_start_tx(struct uart_port *port) really need this.*/ return; - if (atmel_port->rs485.flags & SER_RS485_ENABLED) - atmel_stop_rx(port); + 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 */ UART_PUT_PTCR(port, ATMEL_PDC_TXTEN); @@ -680,9 +682,10 @@ 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) { - /* DMA done, stop TX, start RX for RS485 */ - atmel_start_rx(port); + 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
WARNING: multiple messages have this Message-ID (diff)
From: br@pwrnet.de (Bernhard Roth) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] atmel_serial: RS485: receiving enabled when sending data Date: Mon, 15 Aug 2011 16:28:15 +0200 [thread overview] Message-ID: <4E492CFF.7040905@pwrnet.de> (raw) Hello! 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. This is very useful to - check if the data has been sent correctly over the RS485 bus - assure that no collision happened - check for short circuits/termination issues on the RS485 bus Usually this functionality is realized by hardware, wether controlling the RX-Enable pin of the RS485 transceiver with RTS (driver control signal) or pulling it LOW permanently. The present atmel_serial driver makes this impossible, thus requiring following patch. Usage example: struct serial_rs485 rs485; memset(&rs485, 0, sizeof(rs485)); rs485.flags = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX; ioctl(fd, TIOCSRS485, &rs485); 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 <br@pwrnet.de> Signed-off-by: Claudio Scordino <claudio@evidence.eu.com> --- drivers/tty/serial/atmel_serial.c | 17 ++++++++++------- include/linux/serial.h | 1 + 2 files changed, 11 insertions(+), 7 deletions(-) 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); } /* @@ -356,8 +357,9 @@ static void atmel_start_tx(struct uart_port *port) really need this.*/ return; - if (atmel_port->rs485.flags & SER_RS485_ENABLED) - atmel_stop_rx(port); + 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 */ UART_PUT_PTCR(port, ATMEL_PDC_TXTEN); @@ -680,9 +682,10 @@ 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) { - /* DMA done, stop TX, start RX for RS485 */ - atmel_start_rx(port); + 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
next reply other threads:[~2011-08-15 14:37 UTC|newest] Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-08-15 14:28 Bernhard Roth [this message] 2011-08-15 14:28 ` [PATCH] atmel_serial: RS485: receiving enabled when sending data Bernhard Roth 2011-08-22 21:18 ` Greg KH 2011-08-22 21:18 ` Greg KH 2011-08-23 8:30 ` Claudio Scordino 2011-08-23 8:30 ` Claudio Scordino 2011-08-23 8:30 ` Claudio Scordino 2011-08-23 9:30 ` Russell King - ARM Linux 2011-08-23 9:30 ` Russell King - ARM Linux 2011-08-23 9:30 ` Russell King - ARM Linux 2011-08-23 10:06 ` Claudio Scordino 2011-08-23 10:06 ` Claudio Scordino 2011-08-23 10:14 ` Alan Cox 2011-08-23 10:14 ` Alan Cox 2011-08-23 10:21 ` Russell King - ARM Linux 2011-08-23 10:21 ` Russell King - ARM Linux 2011-08-23 10:21 ` Russell King - ARM Linux 2011-08-23 15:39 ` Greg KH 2011-08-23 15:39 ` Greg KH 2011-08-23 15:39 ` Greg KH 2011-08-24 7:48 ` Claudio Scordino 2011-08-24 7:48 ` Claudio Scordino 2011-11-04 8:19 ` [PATCH] RS485: fix inconsistencies in the meaning of some variables Claudio Scordino 2011-11-04 8:19 ` Claudio Scordino 2011-11-04 10:36 ` Jesper Nilsson 2011-11-04 10:36 ` Jesper Nilsson 2011-11-04 10:36 ` Jesper Nilsson 2011-11-08 9:30 ` Nicolas Ferre 2011-11-08 9:30 ` Nicolas Ferre 2011-11-08 9:59 ` Jean-Christophe PLAGNIOL-VILLARD 2011-11-08 9:59 ` Jean-Christophe PLAGNIOL-VILLARD 2011-11-08 9:59 ` Jean-Christophe PLAGNIOL-VILLARD 2011-11-08 10:48 ` Claudio Scordino 2011-11-08 10:48 ` Claudio Scordino 2011-11-08 13:48 ` Alan Cox 2011-11-08 13:48 ` Alan Cox 2011-11-08 14:24 ` Greg KH 2011-11-08 14:24 ` Greg KH 2011-11-09 14:51 ` Claudio Scordino 2011-11-09 14:51 ` Claudio Scordino 2011-11-13 21:53 ` Wolfram Sang 2011-11-13 21:53 ` Wolfram Sang 2011-11-14 0:37 ` Darron Black 2011-11-14 0:37 ` Darron Black 2011-11-14 0:37 ` Darron Black 2011-11-14 11:11 ` Nicolas Ferre 2011-11-14 11:11 ` Nicolas Ferre 2011-11-14 12:07 ` Alan Cox 2011-11-14 12:07 ` Alan Cox 2011-11-14 8:22 ` Claudio Scordino 2011-11-14 8:22 ` Claudio Scordino 2011-11-14 12:18 ` Nicolas Ferre 2011-11-14 12:18 ` Nicolas Ferre 2011-11-08 15:02 ` Nicolas Ferre 2011-11-08 15:02 ` Nicolas Ferre 2011-11-08 15:45 ` Claudio Scordino 2011-11-08 15:45 ` Claudio Scordino 2011-11-08 16:34 ` Jesper Nilsson 2011-11-08 16:34 ` Jesper Nilsson 2011-11-08 16:34 ` Jesper Nilsson
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=4E492CFF.7040905@pwrnet.de \ --to=br@pwrnet.de \ --cc=claudio@evidence.eu.com \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-serial@vger.kernel.org \ --cc=nicolas.ferre@atmel.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.