From: Javier Martinez Canillas <martinez.javier@gmail.com>
To: Tony Lindgren <tony@atomide.com>
Cc: Alan Cox <alan@linux.intel.com>,
Govindraj Raja <govindraj.raja@ti.com>,
linux-omap@vger.kernel.org, linux-serial@vger.kernel.org,
Javier Martinez Canillas <martinez.javier@gmail.com>
Subject: [PATCH 1/1] omap: serial: Add RS-485 standard support
Date: Sat, 29 Oct 2011 01:04:44 +0200 [thread overview]
Message-ID: <1319843084-16948-1-git-send-email-martinez.javier@gmail.com> (raw)
This patch adds TIA/EIA-485 standard support to OMAP-UART controller driver
by adding handlers for TIOCSRS485 and TIOCGRS485 ioctl commands.
This patch is based on Ilya Yanok <yanok@emcraft.com> patch [1] but it changes
the function serial_omap_update_rts() that raises and lows the Ready-to-Send
control signal. Also, it forces to update the RTS signal when the serial-core
calls serial_omap_set_mctrl().
[1]: http://www.spinics.net/lists/linux-omap/msg58546.html
Signed-off-by: Javier Martinez Canillas <martinez.javier@gmail.com>
---
arch/arm/plat-omap/include/plat/omap-serial.h | 2 +
drivers/tty/serial/Makefile | 2 +-
drivers/tty/serial/omap-serial.c | 139 ++++++++++++++++++++++--
include/linux/serial_reg.h | 2 +
4 files changed, 132 insertions(+), 13 deletions(-)
diff --git a/arch/arm/plat-omap/include/plat/omap-serial.h b/arch/arm/plat-omap/include/plat/omap-serial.h
index 2682043..b7c2c29 100644
--- a/arch/arm/plat-omap/include/plat/omap-serial.h
+++ b/arch/arm/plat-omap/include/plat/omap-serial.h
@@ -111,6 +111,8 @@ struct uart_omap_port {
unsigned char msr_saved_flags;
char name[20];
unsigned long port_activity;
+ struct serial_rs485 rs485;
+ unsigned int tx_in_progress:1, tx_wait_end:1;
};
#endif /* __OMAP_SERIAL_H__ */
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 83b4da6..865f238 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -71,7 +71,7 @@ obj-$(CONFIG_SERIAL_VR41XX) += vr41xx_siu.o
obj-$(CONFIG_SERIAL_SGI_IOC4) += ioc4_serial.o
obj-$(CONFIG_SERIAL_SGI_IOC3) += ioc3_serial.o
obj-$(CONFIG_SERIAL_ATMEL) += atmel_serial.o
-obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
+#obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
obj-$(CONFIG_SERIAL_MSM) += msm_serial.o
obj-$(CONFIG_SERIAL_MSM_HS) += msm_serial_hs.o
obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 5e713d3..d1789f4 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -37,6 +37,7 @@
#include <linux/clk.h>
#include <linux/serial_core.h>
#include <linux/irq.h>
+#include <linux/uaccess.h>
#include <plat/dma.h>
#include <plat/dmtimer.h>
@@ -114,6 +115,56 @@ static void serial_omap_enable_ms(struct uart_port *port)
serial_out(up, UART_IER, up->ier);
}
+static inline void serial_omap_enable_ier_thri(struct uart_omap_port *up)
+{
+ if (!(up->ier & UART_IER_THRI)) {
+ up->ier |= UART_IER_THRI;
+ serial_out(up, UART_IER, up->ier);
+ }
+}
+
+static inline void serial_omap_disable_ier_thri(struct uart_omap_port *up)
+{
+ if (up->ier & UART_IER_THRI) {
+ up->ier &= ~UART_IER_THRI;
+ serial_out(up, UART_IER, up->ier);
+ }
+}
+
+static inline void serial_omap_thri_mode(struct uart_omap_port *up)
+{
+ unsigned char scr = serial_in(up, UART_OMAP_SCR);
+
+ if (up->tx_wait_end)
+ scr |= UART_OMAP_SCR_TX_EMPTY_CTL_IT;
+ else
+ scr &= ~UART_OMAP_SCR_TX_EMPTY_CTL_IT;
+ serial_out(up, UART_OMAP_SCR, scr);
+}
+
+
+static inline void serial_omap_update_rts(struct uart_omap_port *up)
+{
+ unsigned char mcr = up->mcr;
+ int rts_on_send = up->rs485.flags & SER_RS485_RTS_ON_SEND;
+
+ if (up->rs485.flags & SER_RS485_ENABLED) {
+ if (up->tx_in_progress) {
+ if (rts_on_send)
+ mcr |= UART_MCR_RTS;
+ else
+ mcr &= ~UART_MCR_RTS;
+ } else {
+ if (rts_on_send)
+ mcr &= ~UART_MCR_RTS;
+ else
+ mcr |= ~UART_MCR_RTS;
+ }
+ }
+
+ serial_out(up, UART_MCR, mcr);
+}
+
static void serial_omap_stop_tx(struct uart_port *port)
{
struct uart_omap_port *up = (struct uart_omap_port *)port;
@@ -131,9 +182,14 @@ static void serial_omap_stop_tx(struct uart_port *port)
up->uart_dma.tx_dma_channel = OMAP_UART_DMA_CH_FREE;
}
- if (up->ier & UART_IER_THRI) {
- up->ier &= ~UART_IER_THRI;
- serial_out(up, UART_IER, up->ier);
+ if (!(up->rs485.flags & SER_RS485_ENABLED))
+ serial_omap_disable_ier_thri(up);
+ else {
+ up->tx_in_progress = 0;
+ serial_omap_update_rts(up);
+ up->tx_wait_end = 1;
+ serial_omap_thri_mode(up);
+ serial_omap_enable_ier_thri(up);
}
}
@@ -246,14 +302,6 @@ static void transmit_chars(struct uart_omap_port *up)
serial_omap_stop_tx(&up->port);
}
-static inline void serial_omap_enable_ier_thri(struct uart_omap_port *up)
-{
- if (!(up->ier & UART_IER_THRI)) {
- up->ier |= UART_IER_THRI;
- serial_out(up, UART_IER, up->ier);
- }
-}
-
static void serial_omap_start_tx(struct uart_port *port)
{
struct uart_omap_port *up = (struct uart_omap_port *)port;
@@ -261,6 +309,18 @@ static void serial_omap_start_tx(struct uart_port *port)
unsigned int start;
int ret = 0;
+ if (up->rs485.flags & SER_RS485_ENABLED) {
+ if (!up->tx_in_progress) {
+ up->tx_in_progress = 1;
+ serial_omap_update_rts(up);
+ }
+ if (up->tx_wait_end) {
+ up->tx_wait_end = 0;
+ serial_omap_thri_mode(up);
+ serial_omap_disable_ier_thri(up);
+ }
+ }
+
if (!up->use_dma) {
serial_omap_enable_ier_thri(up);
return;
@@ -343,6 +403,11 @@ static unsigned int check_modem_status(struct uart_omap_port *up)
return status;
}
+static inline unsigned int __serial_omap_tx_empty(struct uart_omap_port *up)
+{
+ return serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
+}
+
/**
* serial_omap_irq() - This handles the interrupt from one port
* @irq: uart port irq number
@@ -359,6 +424,16 @@ static inline irqreturn_t serial_omap_irq(int irq, void *dev_id)
return IRQ_NONE;
spin_lock_irqsave(&up->port.lock, flags);
+ if (up->tx_wait_end && (iir & UART_IIR_THRI) &&
+ __serial_omap_tx_empty(up)) {
+ up->tx_wait_end = 0;
+ up->tx_in_progress = 0;
+ serial_omap_thri_mode(up);
+ serial_omap_update_rts(up);
+ serial_omap_disable_ier_thri(up);
+ spin_unlock_irqrestore(&up->port.lock, flags);
+ return IRQ_HANDLED;
+ }
lsr = serial_in(up, UART_LSR);
if (iir & UART_IIR_RLSI) {
if (!up->use_dma) {
@@ -390,7 +465,7 @@ static unsigned int serial_omap_tx_empty(struct uart_port *port)
dev_dbg(up->port.dev, "serial_omap_tx_empty+%d\n", up->pdev->id);
spin_lock_irqsave(&up->port.lock, flags);
- ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
+ ret = __serial_omap_tx_empty(up);
spin_unlock_irqrestore(&up->port.lock, flags);
return ret;
@@ -434,6 +509,10 @@ static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
mcr |= UART_MCR_LOOP;
mcr |= up->mcr;
+
+ if (up->rs485.flags & SER_RS485_ENABLED)
+ serial_omap_update_rts(up);
+
serial_out(up, UART_MCR, mcr);
}
@@ -1028,6 +1107,41 @@ static inline void serial_omap_add_console_port(struct uart_omap_port *up)
#endif
+static int
+serial_omap_ioctl(struct uart_port *port, unsigned int cmd, unsigned long arg)
+{
+ struct serial_rs485 rs485conf;
+ struct uart_omap_port *up = (struct uart_omap_port *)port;
+ unsigned long flags;
+
+ switch (cmd) {
+ case TIOCSRS485:
+ if (copy_from_user(&rs485conf, (struct serial_rs485 *) arg,
+ sizeof(rs485conf)))
+ return -EFAULT;
+
+ spin_lock_irqsave(&up->port.lock, flags);
+ if (!(rs485conf.flags & SER_RS485_ENABLED)) {
+ up->tx_in_progress = 0;
+ up->tx_wait_end = 0;
+ }
+ up->rs485 = rs485conf;
+ serial_omap_update_rts(up);
+ serial_omap_thri_mode(up);
+ spin_unlock_irqrestore(&up->port.lock, flags);
+
+ case TIOCGRS485:
+ if (copy_to_user((struct serial_rs485 *) arg,
+ &(up->rs485), sizeof(rs485conf)))
+ return -EFAULT;
+ break;
+
+ default:
+ return -ENOIOCTLCMD;
+ }
+ return 0;
+}
+
static struct uart_ops serial_omap_pops = {
.tx_empty = serial_omap_tx_empty,
.set_mctrl = serial_omap_set_mctrl,
@@ -1041,6 +1155,7 @@ static struct uart_ops serial_omap_pops = {
.shutdown = serial_omap_shutdown,
.set_termios = serial_omap_set_termios,
.pm = serial_omap_pm,
+ .ioctl = serial_omap_ioctl,
.type = serial_omap_type,
.release_port = serial_omap_release_port,
.request_port = serial_omap_request_port,
diff --git a/include/linux/serial_reg.h b/include/linux/serial_reg.h
index c75bda3..dc6a3f7 100644
--- a/include/linux/serial_reg.h
+++ b/include/linux/serial_reg.h
@@ -362,5 +362,7 @@
#define UART_OMAP_MDR1_CIR_MODE 0x06 /* CIR mode */
#define UART_OMAP_MDR1_DISABLE 0x07 /* Disable (default state) */
+#define UART_OMAP_SCR_TX_EMPTY_CTL_IT 0x04 /* TX Empty IRQ mode */
+
#endif /* _LINUX_SERIAL_REG_H */
--
1.7.4.1
next reply other threads:[~2011-10-28 23:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-28 23:04 Javier Martinez Canillas [this message]
2011-11-03 19:06 ` [PATCH 1/1] omap: serial: Add RS-485 standard support Javier Martinez Canillas
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