diff options
| author | Phil Elwell <phil@raspberrypi.org> | 2017-05-19 18:07:23 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-05-24 16:15:56 +0300 |
| commit | d087e7a991f1f61ee2c07db1be7c5cc2aa373f5d (patch) | |
| tree | 7d5fc11fbb19286d3294af2bb3e5214a2a6cdeec /drivers/tty | |
| parent | 9b7becf103e2689d7f005895130ccf89a153fef1 (diff) | |
| download | linux-d087e7a991f1f61ee2c07db1be7c5cc2aa373f5d.tar.xz | |
serial: 8250: Add CAP_MINI, set for bcm2835aux
The AUX/mini-UART in the BCM2835 family of procesors is a cut-down
8250 clone. In particular it is lacking support for the following
features: CSTOPB PARENB PARODD CMSPAR CS5 CS6
Add a new capability (UART_CAP_MINI) that exposes the restrictions to
the user of the termios API by turning off the unsupported features in
the request.
N.B. It is almost possible to automatically discover the missing
features by reading back the LCR register, but the CSIZE bits don't
cooperate (contrary to the documentation, both bits are significant,
but CS5 and CS6 are mapped to CS7) and the code is much longer.
See: https://github.com/raspberrypi/linux/issues/1561
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/8250/8250.h | 3 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/8250_bcm2835aux.c | 2 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/8250_port.c | 6 |
3 files changed, 10 insertions, 1 deletions
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index ce8d4ffcc425..b2bdc35f7495 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -81,6 +81,9 @@ struct serial8250_config { #define UART_CAP_HFIFO (1 << 14) /* UART has a "hidden" FIFO */ #define UART_CAP_RPM (1 << 15) /* Runtime PM is active while idle */ #define UART_CAP_IRDA (1 << 16) /* UART supports IrDA line discipline */ +#define UART_CAP_MINI (1 << 17) /* Mini UART on BCM283X family lacks: + * STOP PARITY EPAR SPAR WLEN5 WLEN6 + */ #define UART_BUG_QUOT (1 << 0) /* UART has buggy quot LSB */ #define UART_BUG_TXEN (1 << 1) /* UART has buggy TX IIR status */ diff --git a/drivers/tty/serial/8250/8250_bcm2835aux.c b/drivers/tty/serial/8250/8250_bcm2835aux.c index e10f1244409b..a23c7da42ea8 100644 --- a/drivers/tty/serial/8250/8250_bcm2835aux.c +++ b/drivers/tty/serial/8250/8250_bcm2835aux.c @@ -39,7 +39,7 @@ static int bcm2835aux_serial_probe(struct platform_device *pdev) /* initialize data */ spin_lock_init(&data->uart.port.lock); - data->uart.capabilities = UART_CAP_FIFO; + data->uart.capabilities = UART_CAP_FIFO | UART_CAP_MINI; data->uart.port.dev = &pdev->dev; data->uart.port.regshift = 2; data->uart.port.type = PORT_16550; diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index d5b6cee87801..b4e71380a13c 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -2584,6 +2584,12 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, unsigned long flags; unsigned int baud, quot, frac = 0; + if (up->capabilities & UART_CAP_MINI) { + termios->c_cflag &= ~(CSTOPB | PARENB | PARODD | CMSPAR); + if ((termios->c_cflag & CSIZE) == CS5 || + (termios->c_cflag & CSIZE) == CS6) + termios->c_cflag = (termios->c_cflag & ~CSIZE) | CS7; + } cval = serial8250_compute_lcr(up, termios->c_cflag); baud = serial8250_get_baud_rate(port, termios, old); |