Hi, your commit title message is somewhat vague and not really usefull in determining why the change is done. Maybe change it to something like : "Set RS422 mode by default to fix MOXA RS422/RS485 PCIe boards..." Hugo Villeneuve. On Mon, 11 Dec 2023 17:09:49 +0800 Crescent CY Hsieh <crescentcy.hsieh@xxxxxxxx> wrote: > MOXA PCIe RS422/RS485 boards will not function by default because of the > initial default serial interface of all MOXA PCIe boards is set to > RS232. > > This patch fixes the problem above by setting the initial default serial > interface to RS422 for those MOXA RS422/RS485 PCIe boards. > > Signed-off-by: Crescent CY Hsieh <crescentcy.hsieh@xxxxxxxx> > Reviewed-by: Jiri Slaby <jirislaby@xxxxxxxxxx> > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Closes: https://lore.kernel.org/oe-kbuild-all/202312060523.Kmstf65q-lkp@xxxxxxxxx/ > > --- > Changes from v1 to v2: > - Fix issue reported by kernel test robot > - Replace function return type from u32 to static unsigned int > > v1: https://lore.kernel.org/all/20231201074055.259207-1-crescentcy.hsieh@xxxxxxxx/ > > --- > drivers/tty/serial/8250/8250_pci.c | 58 +++++++++++++++++++++++++++++- > 1 file changed, 57 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c > index b2be3783f..42fbbe89e 100644 > --- a/drivers/tty/serial/8250/8250_pci.c > +++ b/drivers/tty/serial/8250/8250_pci.c > @@ -19,6 +19,7 @@ > #include <linux/serial_core.h> > #include <linux/8250_pci.h> > #include <linux/bitops.h> > +#include <linux/bitfield.h> > > #include <asm/byteorder.h> > #include <asm/io.h> > @@ -1968,6 +1969,20 @@ pci_sunix_setup(struct serial_private *priv, > > #define MOXA_GPIO_PIN2 BIT(2) > > +#define MOXA_RS232 0x00 > +#define MOXA_RS422 0x01 > +#define MOXA_RS485_4W 0x0B > +#define MOXA_RS485_2W 0x0F > +#define MOXA_UIR_OFFSET 0x04 > +#define MOXA_EVEN_RS_MASK GENMASK(3, 0) > +#define MOXA_ODD_RS_MASK GENMASK(7, 4) > + > +enum { > + MOXA_SUPP_RS232 = BIT(0), > + MOXA_SUPP_RS422 = BIT(1), > + MOXA_SUPP_RS485 = BIT(2), > +}; > + > static bool pci_moxa_is_mini_pcie(unsigned short device) > { > if (device == PCI_DEVICE_ID_MOXA_CP102N || > @@ -1981,13 +1996,54 @@ static bool pci_moxa_is_mini_pcie(unsigned short device) > return false; > } > > +static unsigned int pci_moxa_supported_rs(struct pci_dev *dev) > +{ > + switch (dev->device & 0x0F00) { > + case 0x0000: > + case 0x0600: > + return MOXA_SUPP_RS232; > + case 0x0100: > + return MOXA_SUPP_RS232 | MOXA_SUPP_RS422 | MOXA_SUPP_RS485; > + case 0x0300: > + return MOXA_SUPP_RS422 | MOXA_SUPP_RS485; > + } > + return 0; > +} > + > +static int pci_moxa_set_interface(const struct pci_dev *dev, > + unsigned int port_idx, > + u8 mode) > +{ > + resource_size_t iobar_addr = pci_resource_start(dev, 2); > + resource_size_t UIR_addr = iobar_addr + MOXA_UIR_OFFSET + port_idx / 2; > + u8 val; > + > + val = inb(UIR_addr); > + > + if (port_idx % 2) { > + val &= ~MOXA_ODD_RS_MASK; > + val |= FIELD_PREP(MOXA_ODD_RS_MASK, mode); > + } else { > + val &= ~MOXA_EVEN_RS_MASK; > + val |= FIELD_PREP(MOXA_EVEN_RS_MASK, mode); > + } > + outb(val, UIR_addr); > + > + return 0; > +} > + > static int pci_moxa_init(struct pci_dev *dev) > { > unsigned short device = dev->device; > resource_size_t iobar_addr = pci_resource_start(dev, 2); > - unsigned int num_ports = (device & 0x00F0) >> 4; > + unsigned int num_ports = (device & 0x00F0) >> 4, i; > u8 val; > > + if (!(pci_moxa_supported_rs(dev) & MOXA_SUPP_RS232)) { > + for (i = 0; i < num_ports; ++i) > + pci_moxa_set_interface(dev, i, MOXA_RS422); > + } > + > /* > * Enable hardware buffer to prevent break signal output when system boots up. > * This hardware buffer is only supported on Mini PCIe series. > -- > 2.34.1 > > -- Hugo Villeneuve <hugo@xxxxxxxxxxx>
