[PATCH 1/2 v2] serial/8250: Add support for RS485 IOCTLs

From: Ricardo Ribalda Delgado
Date: Tue Aug 05 2014 - 05:46:13 EST


This patch allow the users of the 8250 infrastructure to define a
handler for RS485 configration.

If no handler is defined the 8250 driver will work as usual.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx>
--
v2:Change suggested by Alan "One Thousand Gnomes":
- Move rs485 structure further down on the uart_8250_port structure

drivers/tty/serial/8250/8250_core.c | 39 +++++++++++++++++++++++++++++++++++++
include/linux/serial_8250.h | 3 +++
2 files changed, 42 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 1d42dba..b28ed1b 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -2843,6 +2843,42 @@ serial8250_verify_port(struct uart_port *port, struct serial_struct *ser)
return 0;
}

+static int serial8250_ioctl(struct uart_port *port, unsigned int cmd,
+ unsigned long arg)
+{
+ struct uart_8250_port *up =
+ container_of(port, struct uart_8250_port, port);
+ int ret;
+ struct serial_rs485 rs485_config;
+
+ if (!up->rs485_config)
+ return -ENOIOCTLCMD;
+
+ switch (cmd) {
+ case TIOCSRS485:
+ if (copy_from_user(&rs485_config, (void __user *)arg,
+ sizeof(rs485_config)))
+ return -EFAULT;
+
+ ret = up->rs485_config(up, &rs485_config);
+ if (ret)
+ return ret;
+
+ memcpy(&up->rs485, &rs485_config, sizeof(rs485_config));
+
+ return 0;
+ case TIOCGRS485:
+ if (copy_to_user((void __user *)arg, &up->rs485,
+ sizeof(up->rs485)))
+ return -EFAULT;
+ return 0;
+ default:
+ break;
+ }
+
+ return -ENOIOCTLCMD;
+}
+
static const char *
serial8250_type(struct uart_port *port)
{
@@ -2872,6 +2908,7 @@ static struct uart_ops serial8250_pops = {
.request_port = serial8250_request_port,
.config_port = serial8250_config_port,
.verify_port = serial8250_verify_port,
+ .ioctl = serial8250_ioctl,
#ifdef CONFIG_CONSOLE_POLL
.poll_get_char = serial8250_get_poll_char,
.poll_put_char = serial8250_put_poll_char,
@@ -3388,6 +3425,8 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
uart->port.fifosize = up->port.fifosize;
uart->tx_loadsz = up->tx_loadsz;
uart->capabilities = up->capabilities;
+ uart->rs485_config = up->rs485_config;
+ uart->rs485 = up->rs485;

/* Take tx_loadsz from fifosize if it wasn't set separately */
if (uart->port.fifosize && !uart->tx_loadsz)
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index f93649e..6dd6717 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -96,10 +96,13 @@ struct uart_8250_port {
unsigned char msr_saved_flags;

struct uart_8250_dma *dma;
+ struct serial_rs485 rs485;

/* 8250 specific callbacks */
int (*dl_read)(struct uart_8250_port *);
void (*dl_write)(struct uart_8250_port *, int);
+ int (*rs485_config)(struct uart_8250_port *,
+ struct serial_rs485 *rs485);
};

static inline struct uart_8250_port *up_to_u8250p(struct uart_port *up)
--
2.0.1

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