Re: [PATCHv3 2/2] serial: Add driver for the Altera UART

[Thomas Chou]

On 03/25/2010 12:24 AM, Tobias Klauser wrote:
> On 2010-03-24 at 12:05:27 +0100, Andrew Morton<akpm@xxxxxxxxxxxxxxxxxxxx>  wrote:
>    
> > On Wed, 24 Mar 2010 07:47:47 +0100 Tobias Klauser<tklauser@xxxxxxxxxx>  wrote:
> >      
> > > On 2010-03-23 at 22:54:59 +0100, Andrew Morton<akpm@xxxxxxxxxxxxxxxxxxxx>  wrote:
> > >        
> > > > On Fri,  5 Mar 2010 17:52:23 +0100
> > > > Tobias Klauser<tklauser@xxxxxxxxxx>  wrote:
> > > >
> > > >          
> > > > > +	sigs |= (altera_uart_getppdcd(port->line) ? TIOCM_CD : 0);
> > > > > +	sigs |= (altera_uart_getppdtr(port->line) ? TIOCM_DTR : 0);
> > > > >            
> > > > We seem to be missing a few things here.
> > > >
> > > > drivers/serial/altera_uart.c: In function 'altera_uart_get_mctrl':
> > > > drivers/serial/altera_uart.c:100: error: implicit declaration of function 'altera_uart_getppdcd'
> > > > drivers/serial/altera_uart.c:101: error: implicit declaration of function 'altera_uart_getppdtr'
> > > > drivers/serial/altera_uart.c: In function 'altera_uart_set_mctrl':
> > > > drivers/serial/altera_uart.c:114: error: implicit declaration of function 'altera_uart_setppdtr'
> > > >          
> > > These should usually be declared in a board specific header. There were
> > > compatibility macros in altera_uart.c which defined them to NOPs in case
> > > the board header did not properly define them. But I remove them as per
> > > request by Alan Cox (Message-ID: 20100301181920.3952c3e7@xxxxxxxxxxxxxxxxxxx).
> > >
> > > Should we add them again (maybe to altera_uart.h)? Or would it be better
> > > to define a config symbol which is set in the board specific Kconfig and
> > > altera_uart depends on it?
> > >        
> > I guess the latter.
> >
> > There should have been a real implementation of these in the patchset -
> > otherwise the code can't be used or tested.  Confused.
> >      
> Sorry for the confusion.
>
> The last patchset I submitted (with the functions removed from
> altera_uart.c) was tested on a local branch, where I added the macros to
> a global board specific header. I didn't include that one in the patch.
>
> After looking at the code and it's history a bit closer (and also on the
> nios2 specific part) I realised that this macro was probably added
> because the driver was originally based on drivers/serial/mcf.c (the
> macros are present there too).
>
> Also there are currently no board configurations known to me that define
> these macros. So I'd suggest to remove the usage of these macros
> alltogether. We could still add them again (to the board specific part
> and with the config option then) in case there will be a board
> configuration implementing DTR/DCD lines on GPIOs.
>
> Could anyone on nios2-dev verify that there are currently no such board
> configurations?
>
> I'd remove the usage of the macros then and post an updated patch.
>    
Maybe we can add pointers to functions for the DCD/DTR in the struct 
altera_uart_platform_uart. Then board config file can define them if 
they implement these pins, NULL/0 otherwise.

struct altera_uart_platform_uart {
...
    int (*getppdcd)(...);    /* get DCD status */
...

};


static unsigned int altera_uart_get_mctrl(struct uart_port *port)
{
...
    if (port->getppdcd)
        sigs |= (port->getppdcd(...)) ? TIOCM_CD : 0);


- Thomas

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