Re: [PATCH 2/2] serial: 8250_dw: Add support for IrDA SIR mode

[Ed Blake]

On 10/27/16 17:56, Andy Shevchenko wrote:
> On Thu, 2016-10-27 at 17:38 +0100, Ed Blake wrote:
> > Add a set_ldisc function to enable/disable IrDA SIR mode according to
> > the new line discipline.
> Thanks for the patch.
>
> Consider that not all implementations based on 8250_dw support IRDA
> feature. I suppose you need to read capability register bits 6 and 7,
> set flag and then based on the value accept or reject IRDA mode.

Thanks for the review, I'll add this for the second version.

Ed.

> P.S. Use -n when prepare patches to link them if you consider them
> dependent.
>
> > Signed-off-by: Ed Blake <ed.blake@xxxxxxxxxx>
> > ---
> >   drivers/tty/serial/8250/8250_dw.c | 17 +++++++++++++++++
> >   1 file changed, 17 insertions(+)
> >
> > diff --git a/drivers/tty/serial/8250/8250_dw.c
> > b/drivers/tty/serial/8250/8250_dw.c
> > index 459d726..7dd5369 100644
> > --- a/drivers/tty/serial/8250/8250_dw.c
> > +++ b/drivers/tty/serial/8250/8250_dw.c
> > @@ -53,6 +53,8 @@
> >   /* Helper for fifo size calculation */
> >   #define DW_UART_CPR_FIFO_SIZE(a)	(((a >> 16) & 0xff) * 16)
> >   
> > +/* DesignWare specific register fields */
> > +#define DW_UART_MCR_SIRE		BIT(6)
> >   
> >   struct dw8250_data {
> >   	u8			usr_reg;
> > @@ -254,6 +256,20 @@ static void dw8250_set_termios(struct uart_port
> > *p, struct ktermios *termios,
> >   	serial8250_do_set_termios(p, termios, old);
> >   }
> >   
> > +static void dw8250_set_ldisc(struct uart_port *p, struct ktermios
> > *termios)
> > +{
> > +	unsigned int mcr = p->serial_in(p, UART_MCR);
> > +
> > +	if (termios->c_line == N_IRDA)
> > +		mcr |= DW_UART_MCR_SIRE;
> > +	else
> > +		mcr &= ~DW_UART_MCR_SIRE;
> > +
> > +	p->serial_out(p, UART_MCR, mcr);
> > +
> > +	serial8250_do_set_ldisc(p, termios);
> > +}
> > +
> >   /*
> >    * dw8250_fallback_dma_filter will prevent the UART from getting just
> > any free
> >    * channel on platforms that have DMA engines, but don't have any
> > channels
> > @@ -392,6 +408,7 @@ static int dw8250_probe(struct platform_device
> > *pdev)
> >   	p->iotype	= UPIO_MEM;
> >   	p->serial_in	= dw8250_serial_in;
> >   	p->serial_out	= dw8250_serial_out;
> > +	p->set_ldisc	= dw8250_set_ldisc;
> >   
> >   	p->membase = devm_ioremap(dev, regs->start,
> > resource_size(regs));
> >   	if (!p->membase)