target/linux/generic/backport-4.14/950-tty-serial-exar-generalize-rs485-setup.patch

   1 From 9d9398944488cd3a3e1e0912b26fbc4d5921e547 Mon Sep 17 00:00:00 2001
   2 From: Daniel Golle <daniel@makrotopia.org>
   3 Date: Mon, 4 Jun 2018 23:33:07 +0200
   4 Subject: [PATCH] tty: serial: exar: generalize RS485 setup
   5
   6 Move the non-board-specific part of the RS485 initialization from
   7 iot2040_rs485_config function to a new generic function used also for
   8 other boards.
   9 This allows using TIOCGRS485 and TIOCSRS485 on boards (such as mPCIe
  10 serial IO modules) which are hard-wired to RS485 or have jumpers for
  11 their configurations.
  12
  13 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  14 Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
  15 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  16 ---
  17  drivers/tty/serial/8250/8250_exar.c | 38 +++++++++++++++++++----------
  18  1 file changed, 25 insertions(+), 13 deletions(-)
  19
  20 --- a/drivers/tty/serial/8250/8250_exar.c
  21 +++ b/drivers/tty/serial/8250/8250_exar.c
  22 @@ -293,8 +293,32 @@ static int xr17v35x_register_gpio(struct
  23         return 0;
  24  }
  25
  26 +static int generic_rs485_config(struct uart_port *port,
  27 +                               struct serial_rs485 *rs485)
  28 +{
  29 +       bool is_rs485 = !!(rs485->flags & SER_RS485_ENABLED);
  30 +       u8 __iomem *p = port->membase;
  31 +       u8 value;
  32 +
  33 +       value = readb(p + UART_EXAR_FCTR);
  34 +       if (is_rs485)
  35 +               value |= UART_FCTR_EXAR_485;
  36 +       else
  37 +               value &= ~UART_FCTR_EXAR_485;
  38 +
  39 +       writeb(value, p + UART_EXAR_FCTR);
  40 +
  41 +       if (is_rs485)
  42 +               writeb(UART_EXAR_RS485_DLY(4), p + UART_MSR);
  43 +
  44 +       port->rs485 = *rs485;
  45 +
  46 +       return 0;
  47 +}
  48 +
  49  static const struct exar8250_platform exar8250_default_platform = {
  50         .register_gpio = xr17v35x_register_gpio,
  51 +       .rs485_config = generic_rs485_config,
  52  };
  53
  54  static int iot2040_rs485_config(struct uart_port *port,
  55 @@ -327,19 +351,7 @@ static int iot2040_rs485_config(struct u
  56         value |= mode;
  57         writeb(value, p + UART_EXAR_MPIOLVL_7_0);
  58
  59 -       value = readb(p + UART_EXAR_FCTR);
  60 -       if (is_rs485)
  61 -               value |= UART_FCTR_EXAR_485;
  62 -       else
  63 -               value &= ~UART_FCTR_EXAR_485;
  64 -       writeb(value, p + UART_EXAR_FCTR);
  65 -
  66 -       if (is_rs485)
  67 -               writeb(UART_EXAR_RS485_DLY(4), p + UART_MSR);
  68 -
  69 -       port->rs485 = *rs485;
  70 -
  71 -       return 0;
  72 +       return generic_rs485_config(port, rs485);
  73  }
  74
  75  static const struct property_entry iot2040_gpio_properties[] = {