Re: [PATCH v2 2/3] tty: Implement default fallback serial8250_rs485_config

Matwey V. Kornilov
2015-11-07T13:51:40Z

2015-11-07 15:29 GMT+03:00 Peter Hurley <peter@hurleysoftware.com>:
> Hi Matwey,
>
> On 11/07/2015 05:09 AM, Matwey V. Kornilov wrote:
>> When 8250 driver doesn't have its own hardware RS485 support and doesn't
>> want to override rs485_config callback, then default
>> serial8250_rs485_config is used. It just stores supplied by user-space
>> config.
>>
>> Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
>> ---
>> drivers/tty/serial/8250/8250_core.c | 10 ++++++++++
>> 1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
>> index 3912646..8f292da 100644
>> --- a/drivers/tty/serial/8250/8250_core.c
>> +++ b/drivers/tty/serial/8250/8250_core.c
>> @@ -395,6 +395,12 @@ static void serial8250_release_rsa_resource(struct uart_8250_port *up)
>> }
>> }
>> #endif
>> +static int serial8250_rs485_config(struct uart_port *port,
>> + struct serial_rs485 *rs485)
>> +{
>> + port->rs485 = *rs485;
>> + return 0;
>> +}
>>
>> static const struct uart_ops *base_ops;
>> static struct uart_ops univ8250_port_ops;
>> @@ -990,6 +996,10 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
>> uart->port.rs485 = up->port.rs485;
>> uart->dma = up->dma;
>>
>> + /* Use software RS485 support when hardware one is not available */
>> + if (!(uart->capabilities & UART_CAP_HW485) && !uart->port.rs485_config)
>> + uart->port.rs485_config = serial8250_rs485_config;
>
> To setup a default 8250 port function,
> 1. define the default 8250 port function in 8250/8250_port.c
> 2. add the port function to the dispatch table (serial8250_pops)

rs485_config is not a member of struct uart_ops, should I add it there?

> 3. add a test for 8250 sub-driver override in serial8250_register_8250_port()
> Eg.,
>
> if (up->port.rs485_config)
> uart->port.rs485_config = up->port.rs485_config;
>
> Regards,
> Peter Hurley
>
>> /* Take tx_loadsz from fifosize if it wasn't set separately */
>> if (uart->port.fifosize && !uart->tx_loadsz)
>> uart->tx_loadsz = uart->port.fifosize;
>>
>

--
With best regards,
Matwey V. Kornilov.
Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia
119991, Moscow, Universitetsky pr-k 13, +7 (495) 9392382