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SubjectRe: [PATCH 1/4] serial: 8250: Copy em485 from port to real port.
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On Wed, 2018-06-06 at 14:15 +0200, Giulio Benetti wrote:
> Il 06/06/2018 13:56, Andy Shevchenko ha scritto:
> > On Wed, 2018-06-06 at 11:49 +0200, Giulio Benetti wrote:
> > > em485 gets lost during
> > >
> > > Copy em485 to final uart port.
> > >
> >
> > Is it needed at all?
> >
> > The individual driver decides either to use software emulation (and
> > calls explicitly serial8250_em485_init() for that) or do HW assisted
> > stuff.
>
> In 8250_dw.c, during probe(), I need to call dw8250_rs485_config()
> against local struct uart_8250_port uart = {};
> Inside serial8250_register_8250_port() not all uart fields are
> copied(em485 too).
> So after probe, em485 is NULL.
>
> Another way could be to call dw8250_rs485_config() against real uart
> port, after calling serial8250_register_8250_port(),
> would it make sense?

Look at OMAP case closely. They have a callback to configure RS485 which
is called in uart_set_rs485_config() which is called whenever user
space does TIOCGRS485 IOCTL.

So, it's completely driven by user space which makes sense by my
opinion.

--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy

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