On Mon, Apr 18, 2022 at 2:02 AM Maciej W. Rozycki <macro@xxxxxxxxxxx> wrote:
>
> The EndRun PTP/1588 dual serial port device is based on the Oxford
> Semiconductor OXPCIe952 UART device with the PCI vendor:device ID set
> for EndRun Technologies and is therefore driven by a fixed 62.5MHz clock
> input derived from the 100MHz PCI Express clock. The clock rate is
> divided by the oversampling rate of 16 as it is supplied to the baud
> rate generator, yielding the baud base of 3906250.
>
> Replace the incorrect baud base of 4000000 with the right value of
> 3906250 then, complementing commit 6cbe45d8ac93 ("serial: 8250: Correct
> the clock for OxSemi PCIe devices").
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxx>
> Fixes: 1bc8cde46a159 ("8250_pci: Added driver for Endrun Technologies PTP PCIe card.")
> ---
> New change in v4, factored out from 2/5.
> ---
> drivers/tty/serial/8250/8250_pci.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> linux-serial-8250-endrun-pcie-clock.diff
> Index: linux-macro/drivers/tty/serial/8250/8250_pci.c
> ===================================================================
> --- linux-macro.orig/drivers/tty/serial/8250/8250_pci.c
> +++ linux-macro/drivers/tty/serial/8250/8250_pci.c
> @@ -2667,7 +2667,7 @@ enum pci_board_num_t {
> pbn_panacom2,
> pbn_panacom4,
> pbn_plx_romulus,
> - pbn_endrun_2_4000000,
> + pbn_endrun_2_3906250,
> pbn_oxsemi,
> pbn_oxsemi_1_3906250,
> pbn_oxsemi_2_3906250,
> @@ -3195,10 +3195,10 @@ static struct pciserial_board pci_boards
> * signal now many ports are available
> * 2 port 952 Uart support
> */
> - [pbn_endrun_2_4000000] = {
> + [pbn_endrun_2_3906250] = {
> .flags = FL_BASE0,
> .num_ports = 2,
> - .base_baud = 4000000,
> + .base_baud = 3906250,
> .uart_offset = 0x200,
> .first_offset = 0x1000,
> },
> @@ -4128,7 +4128,7 @@ static const struct pci_device_id serial
> */
> { PCI_VENDOR_ID_ENDRUN, PCI_DEVICE_ID_ENDRUN_1588,
> PCI_ANY_ID, PCI_ANY_ID, 0, 0,
> - pbn_endrun_2_4000000 },
> + pbn_endrun_2_3906250 },
> /*
> * Quatech cards. These actually have configurable clocks but for
> * now we just use the default.
--
With Best Regards,
Andy Shevchenko
