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SubjectRe: [PATCH] atmel_serial: RS485: receiving enabled when sending data
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 <br@pwrnet.de>
Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
---
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


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