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| author | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2026-01-22 11:19:48 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-01-23 17:24:55 +0100 |
| commit | 3f0716c604e81d8440b16d0d8f5420c4a6f3c17a (patch) | |
| tree | 011c617d39fc49a9755b20635a2428cf5df6ea18 /drivers/tty/serial | |
| parent | 1250ebacd4cc59ede613f95e16aba309f364c0f6 (diff) | |
| download | linux-3f0716c604e81d8440b16d0d8f5420c4a6f3c17a.tar.gz linux-3f0716c604e81d8440b16d0d8f5420c4a6f3c17a.tar.bz2 linux-3f0716c604e81d8440b16d0d8f5420c4a6f3c17a.zip | |
serial: 8250_pci: Remove custom deprecated baud setting routine
As comments mentioned this is old (and actually deprecated) interface
to set custom baud rates. This interface has limitations as it only
allows to set a single opaque value called "custom_divisor". If the HW
needs more complex settings (like fractional divisor) it must somehow
encode this. This is horrid interface that is very driver specific
and not flexible. Meanwhile Linux has established way to set free
baud rate settings via BOTHER [1]. With all this being said, remove
deprecated interface for good.
Link: https://stackoverflow.com/questions/12646324/how-can-i-set-a-custom-baud-rate-on-linux [1]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260122102349.2395423-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial')
| -rw-r--r-- | drivers/tty/serial/8250/8250_pci.c | 91 |
1 files changed, 40 insertions, 51 deletions
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index c5a932f48f74..8da725cdf9a9 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -1205,60 +1205,49 @@ static unsigned int pci_oxsemi_tornado_get_divisor(struct uart_port *port, u8 tcr; int i; - /* Old custom speed handling. */ - if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) { - unsigned int cust_div = port->custom_divisor; - - quot = cust_div & UART_DIV_MAX; - tcr = (cust_div >> 16) & OXSEMI_TORNADO_TCR_MASK; - cpr = (cust_div >> 20) & OXSEMI_TORNADO_CPR_MASK; - if (cpr < OXSEMI_TORNADO_CPR_MIN) - cpr = OXSEMI_TORNADO_CPR_DEF; - } else { - best_squot = quot_scale; - for (i = 0; i < ARRAY_SIZE(p); i++) { - unsigned int spre; - unsigned int srem; - u8 cp; - u8 tc; - - tc = p[i][0]; - cp = p[i][1]; - spre = tc * cp; - - srem = sdiv % spre; - if (srem > spre / 2) - srem = spre - srem; - squot = DIV_ROUND_CLOSEST(srem * quot_scale, spre); - - if (srem == 0) { - tcr = tc; - cpr = cp; - quot = sdiv / spre; - break; - } else if (squot < best_squot) { - best_squot = squot; - tcr = tc; - cpr = cp; - quot = DIV_ROUND_CLOSEST(sdiv, spre); - } + best_squot = quot_scale; + for (i = 0; i < ARRAY_SIZE(p); i++) { + unsigned int spre; + unsigned int srem; + u8 cp; + u8 tc; + + tc = p[i][0]; + cp = p[i][1]; + spre = tc * cp; + + srem = sdiv % spre; + if (srem > spre / 2) + srem = spre - srem; + squot = DIV_ROUND_CLOSEST(srem * quot_scale, spre); + + if (srem == 0) { + tcr = tc; + cpr = cp; + quot = sdiv / spre; + break; + } else if (squot < best_squot) { + best_squot = squot; + tcr = tc; + cpr = cp; + quot = DIV_ROUND_CLOSEST(sdiv, spre); } - while (tcr <= (OXSEMI_TORNADO_TCR_MASK + 1) >> 1 && - quot % 2 == 0) { + } + while (tcr <= (OXSEMI_TORNADO_TCR_MASK + 1) >> 1 && + quot % 2 == 0) { + quot >>= 1; + tcr <<= 1; + } + while (quot > UART_DIV_MAX) { + if (tcr <= (OXSEMI_TORNADO_TCR_MASK + 1) >> 1) { quot >>= 1; tcr <<= 1; - } - while (quot > UART_DIV_MAX) { - if (tcr <= (OXSEMI_TORNADO_TCR_MASK + 1) >> 1) { - quot >>= 1; - tcr <<= 1; - } else if (cpr <= OXSEMI_TORNADO_CPR_MASK >> 1) { - quot >>= 1; - cpr <<= 1; - } else { - quot = quot * cpr / OXSEMI_TORNADO_CPR_MASK; - cpr = OXSEMI_TORNADO_CPR_MASK; - } + } else if (cpr <= OXSEMI_TORNADO_CPR_MASK >> 1) { + quot >>= 1; + cpr <<= 1; + } else { + quot = quot * cpr / OXSEMI_TORNADO_CPR_MASK; + cpr = OXSEMI_TORNADO_CPR_MASK; } } |