On Tue, Dec 15, 2020 at 02:06:09PM +0000, Flavio Suligoi wrote:
> Hi Greg,
>
>
> > > > > + chip_name = "F81216H";
> > > > > + break;
> > > > > case CHIP_ID_F81216:
> > > > > + chip_name = "F81216";
> > > > > break;
> > > > > default:
> > > > > return -ENODEV;
> > > > > }
> > > > >
> > > > > pdata->pid = chip;
> > > > > +
> > > > > + pr_info("%s%s%s Fintek %s\n",
> > > > > + uart->port.dev ? dev_name(uart->port.dev) : "",
> > > > > + uart->port.dev ? ": " : "",
> > > > > + uart->port.name,
> > > > > + chip_name);
> > > >
> > > > Drivers, if all goes well, should not print anything to the kernel
> > log.
> > > > This isn't ok.
> > > >
> > > > And even if it was, dev_info() would be the correct thing to do...
> > >
> > > Ok, too many information in the driver.
> > >
> > > But what do you think about the possibility to introduce
> > > a new additional field, in "serial8250_config" structure,
> > > such as "extra_name" or something like this:
> > >
> > > struct serial8250_config {
> > > const char *name;
> > > const char *extra_name;
> > > unsigned short fifo_size;
> > > unsigned short tx_loadsz;
> > > unsigned char fcr;
> > > unsigned char rxtrig_bytes[UART_FCR_R_TRIG_MAX_STATE];
> > > unsigned int flags;
> > > };
> > >
> > > In this way, if required, each driver can fill this
> > > additional field, for example adding the name of
> > > the particular uart chip or other useful info.
> > >
> > > As result, for example, the "uart_report_port" function output
> > > could be something like this:
> > >
> > > 00:01: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A -
> > Fintek F81216AD
> > > 00:02: ttyS3 at I/O 0x2e8 (irq = 11, base_baud = 115200) is a 16550A -
> > Fintek F81216AD
> > >
> > > where the "extra_name", if not empty, is printed
> > > at the end of the line.
> > > For practical space reasons, the "extra_name" length
> > > can be limited to 16 chars.
> >
> > Why? What tool will use this, and why would userspace care about it?
> >
> > What problem are you trying to solve here?
>
> I try to explain my requirement:
>
> we produce some x86 boards with multistandard RS232/422/485 ports
> and, to have this feature, in some of these boards, we use a
> Fintek uart or superIO.
> So this additional info "extra_name" can be useful for
> a quick check if the serial ports are multistandard or not,
> without any other investigations, but using only a simple command
> like:
>
> dmesg| grep ttyS
But as they work the same, why does it matter?
Userspace should not care here. Isn't there some other id you can
read/query for a hardware database tool to determine this?
Printing a random string to the kernel log is not a good way to do
hardware descriptions in a format that everyone can easily parse them :)
thanks,
greg k-h
