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| author | Maciej W. Rozycki <macro@orcam.me.uk> | 2021-06-26 06:11:21 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-21 12:35:01 +0200 |
| commit | e7b91932f6223f2996560662623f1c9730fea21f (patch) | |
| tree | 131920cf231702af840a22ba399539d6912899b3 | |
| parent | b1442c55ce8977aa304c9f5a078e895fac5d1d63 (diff) | |
| download | linux-stable-e7b91932f6223f2996560662623f1c9730fea21f.tar.gz linux-stable-e7b91932f6223f2996560662623f1c9730fea21f.tar.bz2 linux-stable-e7b91932f6223f2996560662623f1c9730fea21f.zip | |
serial: core: Report magic multiplier extra baud rates
Report extra baud rates supported above the base rate for ports with the
UPF_MAGIC_MULTIPLIER property, so that people have a way to find out
that they can be used with their system, e.g.:
Serial: 8250/16550 driver, 5 ports, IRQ sharing enabled
printk: console [ttyS0] disabled
serial8250.0: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
serial8250.0: ttyS0 extra baud rates supported: 230400, 460800
printk: console [ttyS0] enabled
printk: bootconsole [uart8250] disabled
serial8250.0: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is a 16550A
serial8250.0: ttyS1 extra baud rates supported: 230400, 460800
serial8250.0: ttyS2 at MMIO 0x1f000900 (irq = 20, base_baud = 230400) is a 16550A
Otherwise there is no clear way to figure this out, as the feature is
only reported as an obscure TTY flag in bit 16:
$ cat /sys/class/tty/ttyS[0-2]/flags
0x10010040
0x10010040
0x90000040
$
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106260334170.37803@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 69092deba11f..79bd2f44d765 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2314,6 +2314,14 @@ uart_report_port(struct uart_driver *drv, struct uart_port *port) port->dev ? ": " : "", port->name, address, port->irq, port->uartclk / 16, uart_type(port)); + + /* The magic multiplier feature is a bit obscure, so report it too. */ + if (port->flags & UPF_MAGIC_MULTIPLIER) + pr_info("%s%s%s extra baud rates supported: %d, %d", + port->dev ? dev_name(port->dev) : "", + port->dev ? ": " : "", + port->name, + port->uartclk / 8, port->uartclk / 4); } static void |