From: Matthew Howell <matthew.howell@xxxxxxxxxxxx> Sealevel XR17V35X based cards utilize DTR to control RS-485 Enable, but the current implementation of 8250_exar uses RTS for the auto-RS485-Enable mode of the XR17V35X UARTs. This patch implements DTR Auto-RS485 on Sealevel cards. Link: https://lore.kernel.org/all/1b3f5094-0b14-5a22-8654-a64eb8b7666d@xxxxxxxxxxxx/T/ Signed-off-by: Matthew Howell <matthew.howell@xxxxxxxxxxxx> --- V4->V5 Fixed typo in commit message Split readb and writeb into multiple lines/variables Removed "store original LCR" since it was clear from code Various small fixes to tabs and whitespace diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c index 3886f78ecbbf..9866dfc84953 100644 --- a/drivers/tty/serial/8250/8250_exar.c +++ b/drivers/tty/serial/8250/8250_exar.c @@ -78,6 +78,9 @@ #define UART_EXAR_RS485_DLY(x) ((x) << 4) +#define UART_EXAR_DLD 0x02 /* Divisor Fractional */ +#define UART_EXAR_DLD_485_POLARITY 0x80 /* RS-485 Enable Signal Polarity */ + /* * IOT2040 MPIO wiring semantics: * @@ -439,6 +442,41 @@ static int generic_rs485_config(struct uart_port *port, struct ktermios *termios return 0; } +static int sealevel_rs485_config(struct uart_port *port, struct ktermios *termios, + struct serial_rs485 *rs485) +{ + u8 __iomem *p = port->membase; + u8 old_lcr; + u8 efr; + u8 dld; + + generic_rs485_config(port, termios, rs485); + + if (rs485->flags & SER_RS485_ENABLED) { + old_lcr = readb(p + UART_LCR); + + /* Set EFR[4]=1 to enable enhanced feature registers */ + efr = readb(p + UART_XR_EFR); + efr |= UART_EFR_ECB; + writeb(efr, p + UART_XR_EFR); + + /* Set MCR to use DTR as Auto-RS485 Enable signal */ + writeb(UART_MCR_OUT1, p + UART_MCR); + + /* Set LCR[7]=1 to enable access to DLD register */ + writeb(old_lcr | UART_LCR_DLAB, p + UART_LCR); + + /* Set DLD[7]=1 for inverted RS485 Enable logic */ + dld = readb(p + UART_EXAR_DLD); + dld |= UART_EXAR_DLD_485_POLARITY; + writeb(dld, p + UART_EXAR_DLD); + + writeb(old_lcr, p + UART_LCR); + } + + return 0; +} + static const struct serial_rs485 generic_rs485_supported = { .flags = SER_RS485_ENABLED, }; @@ -744,6 +782,19 @@ static int __maybe_unused exar_resume(struct device *dev) return 0; } +static int pci_sealevel_setup(struct exar8250 *priv, struct pci_dev *pcidev, + struct uart_8250_port *port, int idx) +{ + int ret = pci_xr17v35x_setup(priv, pcidev, port, idx); + + if (ret) + return ret; + + port->port.rs485_config = sealevel_rs485_config; + + return 0; +} + static SIMPLE_DEV_PM_OPS(exar_pci_pm, exar_suspend, exar_resume); static const struct exar8250_board pbn_fastcom335_2 = { @@ -809,6 +860,17 @@ static const struct exar8250_board pbn_exar_XR17V8358 = { .exit = pci_xr17v35x_exit, }; +static const struct exar8250_board pbn_sealevel = { + .setup = pci_sealevel_setup, + .exit = pci_xr17v35x_exit, +}; + +static const struct exar8250_board pbn_sealevel_16 = { + .num_ports = 16, + .setup = pci_sealevel_setup, + .exit = pci_xr17v35x_exit, +}; + #define CONNECT_DEVICE(devid, sdevid, bd) { \ PCI_DEVICE_SUB( \ PCI_VENDOR_ID_EXAR, \ @@ -838,6 +900,15 @@ static const struct exar8250_board pbn_exar_XR17V8358 = { (kernel_ulong_t)&bd \ } +#define SEALEVEL_DEVICE(devid, bd) { \ + PCI_DEVICE_SUB( \ + PCI_VENDOR_ID_EXAR, \ + PCI_DEVICE_ID_EXAR_##devid, \ + PCI_VENDOR_ID_SEALEVEL, \ + PCI_ANY_ID), 0, 0, \ + (kernel_ulong_t)&bd \ + } + static const struct pci_device_id exar_pci_tbl[] = { EXAR_DEVICE(ACCESSIO, COM_2S, pbn_exar_XR17C15x), EXAR_DEVICE(ACCESSIO, COM_4S, pbn_exar_XR17C15x), @@ -860,6 +931,12 @@ static const struct pci_device_id exar_pci_tbl[] = { CONNECT_DEVICE(XR17C154, UART_4_485, pbn_connect), CONNECT_DEVICE(XR17C158, UART_8_485, pbn_connect), + SEALEVEL_DEVICE(XR17V352, pbn_sealevel), + SEALEVEL_DEVICE(XR17V354, pbn_sealevel), + SEALEVEL_DEVICE(XR17V358, pbn_sealevel), + SEALEVEL_DEVICE(XR17V4358, pbn_sealevel_16), + SEALEVEL_DEVICE(XR17V8358, pbn_sealevel_16), + IBM_DEVICE(XR17C152, SATURN_SERIAL_ONE_PORT, pbn_exar_ibm_saturn), /* USRobotics USR298x-OEM PCI Modems */
