Re: [RFC 3/5] serial: add support for Technologic Systems TS-5500 RS-485 serial port

Alan Cox
2011-04-30T10:17:26Z

> --- a/drivers/tty/serial/8250.c
> +++ b/drivers/tty/serial/8250.c
> @@ -109,6 +109,13 @@ static unsigned int skip_txen_test; /* force skip of txen test at init time */
> #define CONFIG_HUB6 1
>
> #include <asm/serial.h>
> +
> +/* TS-5500 related stuff */
> +#ifdef CONFIG_SERIAL_8250_TS5500_485_TIMER
> +#define TS5500_TIMER2_SPEED_ADDR 0x42
> +#define TS5500_485_SERIAL_PORT 0x02
> +#endif
> +
> /*
> * SERIAL_PORT_DFNS tells us about built-in ports that have no
> * standard enumeration mechanism. Platforms that can find all
> @@ -437,6 +444,25 @@ static void au_serial_out(struct uart_port *p, int offset, int value)
> __raw_writel(value, p->membase + offset);
> }
>
> +#ifdef CONFIG_SERIAL_8250_TS5500_485_TIMER
> +void serial8250_ts5500_set_termios(struct uart_port *port,
> + struct ktermios *new,
> + struct ktermios *old)
> +{
> + u16 speed;
> +
> + if (new->c_ospeed >= 9600 && port->line == TS5500_485_SERIAL_PORT) {
> + speed = ((115200 * 2) / new->c_ospeed);
> +
> + /* This should be written by low byte followed by high byte */
> + spin_lock_irq(&port->lock);
> + outb((speed & 0x0F), TS5500_TIMER2_SPEED_ADDR);
> + outb((speed >> 8), TS5500_TIMER2_SPEED_ADDR);
> + spin_unlock_irq(&port->lock);
> + }
> +}
> +#endif

Please don't put board specific magic in this file, we are desperately
trying to get rid of it.

> +
> static unsigned int tsi_serial_in(struct uart_port *p, int offset)
> {
> unsigned int tmp;
> @@ -2464,6 +2490,10 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
> /* Don't rewrite B0 */
> if (tty_termios_baud_rate(termios))
> tty_termios_encode_baud_rate(termios, baud, baud);
> +
> +#ifdef CONFIG_SERIAL_8250_TS5500_485_TIMER
> + serial8250_ts5500_set_termios(port, termios, old);
> +#endif
> }
> EXPORT_SYMBOL(serial8250_do_set_termios);

Provide your own set_termios method and then call into this one (which is
why it is exported)

> diff --git a/drivers/tty/serial/ts5500-auto485.c b/drivers/tty/serial/ts5500-auto485.c
> new file mode 100644
> index 0000000..fd01aa0
> --- /dev/null
> +++ b/drivers/tty/serial/ts5500-auto485.c
> @@ -0,0 +1,45 @@
> +/*
> + * ts5500-auto485.c - support for the TS-5500 auto485 feature

This needs documentation and description. Also we have runtime 485
switching ioctls so any code should really be using those and extending
them as needed.