6.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Crescent Hsieh <crescentcy.hsieh@xxxxxxxx> commit 0ac18dac43103ab1df6d26ec9a781c0126f83ced upstream. Normally, the number of ports is indicated by the third digit of the device ID on Moxa PCI serial boards. For example, `0x1121` indicates a device with 2 ports. However, `CP116E_A_A` and `CP116E_A_B` are exceptions; they have 8 ports, but the third digit of the device ID is `6`. This patch introduces a function to retrieve the number of ports on Moxa PCI serial boards, addressing the issue described above. Fixes: 37058fd5d239 ("tty: serial: 8250: Add support for MOXA Mini PCIe boards") Cc: stable <stable@xxxxxxxxxx> Signed-off-by: Crescent Hsieh <crescentcy.hsieh@xxxxxxxx> Reviewed-by: Andy Shevchenko <andy@xxxxxxxxxx> Link: https://lore.kernel.org/r/20240617063058.18866-1-crescentcy.hsieh@xxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/8250/8250_pci.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -1985,6 +1985,17 @@ enum { MOXA_SUPP_RS485 = BIT(2), }; +static unsigned short moxa_get_nports(unsigned short device) +{ + switch (device) { + case PCI_DEVICE_ID_MOXA_CP116E_A_A: + case PCI_DEVICE_ID_MOXA_CP116E_A_B: + return 8; + } + + return FIELD_GET(0x00F0, device); +} + static bool pci_moxa_is_mini_pcie(unsigned short device) { if (device == PCI_DEVICE_ID_MOXA_CP102N || @@ -2038,7 +2049,7 @@ static int pci_moxa_init(struct pci_dev { unsigned short device = dev->device; resource_size_t iobar_addr = pci_resource_start(dev, 2); - unsigned int num_ports = (device & 0x00F0) >> 4, i; + unsigned int i, num_ports = moxa_get_nports(device); u8 val, init_mode = MOXA_RS232; if (!(pci_moxa_supported_rs(dev) & MOXA_SUPP_RS232)) {