lkml.org 
[lkml]   [2010]   [Aug]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] U6715 16550A serial driver support
    On Mon, 2 Aug 2010 10:58:39 +0200
    Philippe Langlais <philippe.langlais@stericsson.com> wrote:

    > UART Features extract from STEricsson U6715 data-sheet (arm926 SoC for mobile phone):
    > * Fully compatible with industry standard 16C550 and 16C450 from various
    > manufacturers
    > * RX and TX 64 byte FIFO reduces CPU interrupts
    > * Full double buffering
    > * Modem control signals include CTS, RTS, (and DSR, DTR on UART1 only)
    > * Automatic baud rate selection
    > * Manual or automatic RTS/CTS smart hardware flow control
    > * Programmable serial characteristics:
    > ___ Baud rate generation (50 to 3.25M baud)
    > ___ 5, 6, 7 or 8-bit characters
    > ___ Even, odd or no-parity bit generation and detection
    > ___ 1, 1.5 or 2 stop bit generation
    > * Independent control of transmit, receive, line status, data set interrupts and FIFOs
    > * Full status-reporting capabilities
    > * Separate DMA signaling for RX and TX
    > * Timed interrupt to spread receive interrupt on known duration
    > * DMA time-out interrupt to allow detection of end of reception
    > * Carkit pulse coding and decoding compliant with USB carkit control interface [40]
    >
    > In 16550A auto-configuration, if the fifo size is 64 then it's an U6 16550A port
    > Add set_termios hook & export serial8250_do_set_termios to change uart
    > clock following baudrate

    Confused.

    > ...
    >
    > --- a/include/linux/serial_8250.h
    > +++ b/include/linux/serial_8250.h
    > @@ -32,6 +32,9 @@ struct plat_serial8250_port {
    > unsigned int type; /* If UPF_FIXED_TYPE */
    > unsigned int (*serial_in)(struct uart_port *, int);
    > void (*serial_out)(struct uart_port *, int, int);
    > + void (*set_termios)(struct uart_port *,
    > + struct ktermios *new,
    > + struct ktermios *old);
    > };
    >
    > ...
    >
    > --- a/include/linux/serial_core.h
    > +++ b/include/linux/serial_core.h
    > @@ -279,6 +279,9 @@ struct uart_port {
    > unsigned char __iomem *membase; /* read/write[bwl] */
    > unsigned int (*serial_in)(struct uart_port *, int);
    > void (*serial_out)(struct uart_port *, int, int);
    > + void (*set_termios)(struct uart_port *,
    > + struct ktermios *new,
    > + struct ktermios *old);
    > unsigned int irq; /* irq number */
    > unsigned long irqflags; /* irq flags */
    > unsigned int uartclk; /* base uart clock */

    The patch adds these .set_termios hooks but doesn't actually use them
    for anything.

    The changelog doesn't tell us _why_ this was done (it should) and
    lacking any code to look at it's all a bit mysterious.



    \
     
     \ /
      Last update: 2010-08-04 21:55    [W:0.026 / U:0.020 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site