Nit, your "To:" line was corrupted :( On Mon, Mar 13, 2023 at 03:04:16AM +0200, Jarkko Sonninen wrote: > Add support for RS-485 in Exar USB adapters. > RS-485 mode is controlled by TIOCGRS485 and TIOCSRS485 ioctls. > Gpio mode register is set to enable RS-485. > > Signed-off-by: Jarkko Sonninen <kasper@xxxxxx> > --- > drivers/usb/serial/xr_serial.c | 72 +++++++++++++++++++++++++++++++++- > 1 file changed, 71 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c > index fdb0aae546c3..edbb6add087c 100644 > --- a/drivers/usb/serial/xr_serial.c > +++ b/drivers/usb/serial/xr_serial.c > @@ -93,6 +93,7 @@ struct xr_txrx_clk_mask { > #define XR_GPIO_MODE_SEL_DTR_DSR 0x2 > #define XR_GPIO_MODE_SEL_RS485 0x3 > #define XR_GPIO_MODE_SEL_RS485_ADDR 0x4 > +#define XR_GPIO_MODE_RS485_TX_H 0x8 > #define XR_GPIO_MODE_TX_TOGGLE 0x100 > #define XR_GPIO_MODE_RX_TOGGLE 0x200 > > @@ -237,6 +238,8 @@ static const struct xr_type xr_types[] = { > struct xr_data { > const struct xr_type *type; > u8 channel; /* zero-based index or interface number */ > + struct serial_rs485 rs485; > + spinlock_t lock; > }; > > static int xr_set_reg(struct usb_serial_port *port, u8 channel, u16 reg, u16 val) > @@ -629,6 +632,7 @@ static void xr_set_flow_mode(struct tty_struct *tty, > struct xr_data *data = usb_get_serial_port_data(port); > const struct xr_type *type = data->type; > u16 flow, gpio_mode; > + unsigned long flags, rs485_flags; > int ret; > > ret = xr_get_reg_uart(port, type->gpio_mode, &gpio_mode); > @@ -645,9 +649,16 @@ static void xr_set_flow_mode(struct tty_struct *tty, > /* Set GPIO mode for controlling the pins manually by default. */ > gpio_mode &= ~XR_GPIO_MODE_SEL_MASK; > > + spin_lock_irqsave(&data->lock, flags); > + rs485_flags = data->rs485.flags; > + spin_unlock_irqrestore(&data->lock, flags); > + if (rs485_flags & SER_RS485_ENABLED) > + gpio_mode |= XR_GPIO_MODE_SEL_RS485 | XR_GPIO_MODE_RS485_TX_H; > + else if (C_CRTSCTS(tty) && C_BAUD(tty) != B0) > + gpio_mode |= XR_GPIO_MODE_SEL_RTS_CTS; > + > if (C_CRTSCTS(tty) && C_BAUD(tty) != B0) { > dev_dbg(&port->dev, "Enabling hardware flow ctrl\n"); > - gpio_mode |= XR_GPIO_MODE_SEL_RTS_CTS; > flow = XR_UART_FLOW_MODE_HW; > } else if (I_IXON(tty)) { > u8 start_char = START_CHAR(tty); > @@ -827,6 +838,64 @@ static void xr_set_termios(struct tty_struct *tty, > xr_set_flow_mode(tty, port, old_termios); > } > > +static int xr_get_rs485_config(struct tty_struct *tty, > + unsigned int __user *argp) > +{ > + struct usb_serial_port *port = tty->driver_data; > + struct xr_data *data = usb_get_serial_port_data(port); > + unsigned long flags; > + struct serial_rs485 rs485; > + > + spin_lock_irqsave(&data->lock, flags); > + memcpy(&rs485, &data->rs485, sizeof(rs485)); Why are you using the stack for this? Why not directly access the real structure instead? And are you sure you need a lock? If so, why? > + spin_unlock_irqrestore(&data->lock, flags); > + dev_dbg(tty->dev, "%s flags %02x\n", __func__, rs485.flags); dev_dbg() provides __func__ for free, so you never need to provide it again. Just use the +f flag when enabling it from userspace. > + > + if (copy_to_user(argp, &rs485, sizeof(rs485))) > + return -EFAULT; > + > + return 0; > +} > + > +static int xr_set_rs485_config(struct tty_struct *tty, > + unsigned long __user *argp) > +{ > + struct usb_serial_port *port = tty->driver_data; > + struct xr_data *data = usb_get_serial_port_data(port); > + struct serial_rs485 rs485; > + unsigned long flags; > + > + if (copy_from_user(&rs485, argp, sizeof(rs485))) > + return -EFAULT; > + > + dev_dbg(tty->dev, "%s flags %02x\n", __func__, rs485.flags); Again, no need for __func__. > + rs485.flags &= SER_RS485_ENABLED; > + spin_lock_irqsave(&data->lock, flags); > + memcpy(&data->rs485, &rs485, sizeof(rs485)); > + spin_unlock_irqrestore(&data->lock, flags); > + xr_set_flow_mode(tty, port, 0); > + > + if (copy_to_user(argp, &data->rs485, sizeof(data->rs485))) > + return -EFAULT; > + > + return 0; > +} > + > + > +static int xr_ioctl(struct tty_struct *tty, > + unsigned int cmd, unsigned long arg) Very odd indentation, please fix up. > +{ > + void __user *argp = (void __user *)arg; > + > + switch (cmd) { > + case TIOCGRS485: > + return xr_get_rs485_config(tty, argp); > + case TIOCSRS485: > + return xr_set_rs485_config(tty, argp); > + } > + return -ENOIOCTLCMD; Wrong ioctl return value :( thanks, greg k-h