[PATCH] atmel_serial: Atmel RS485 support v2
Claudio Scordino
claudio at evidence.eu.com
Mon Mar 29 03:16:20 EDT 2010
Hi all,
this is the new version of the patch to add RS485 support to the
atmel_serial driver. It's been changed according to Ryan Mallon's
comments.
This new patch has been tested again (with and without DMA) by Sebastian
Heutling (CC:-ed).
Many thanks to all,
Claudio
atmel_serial: Atmel RS485 support
Signed-off-by: Claudio Scordino <claudio at evidence.eu.com>
Signed-off-by: Michael Trimarchi <michael at evidence.eu.com>
Signed-off-by: Rick Bronson <rick at efn.org>
Signed-off-by: Sebastian Heutling <Sebastian.Heutling at who-ing.de>
---
arch/arm/include/asm/ioctls.h | 2 +
arch/arm/mach-at91/include/mach/board.h | 2 +
drivers/serial/atmel_serial.c | 244 ++++++++++++++++++++++++++-----
3 files changed, 212 insertions(+), 36 deletions(-)
diff --git a/arch/arm/include/asm/ioctls.h b/arch/arm/include/asm/ioctls.h
index a91d8a1..82f2177 100644
--- a/arch/arm/include/asm/ioctls.h
+++ b/arch/arm/include/asm/ioctls.h
@@ -70,6 +70,8 @@
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
#define FIOQSIZE 0x545E
+#define TIOCSRS485 0x5461
+
/* Used for packet mode */
#define TIOCPKT_DATA 0
#define TIOCPKT_FLUSHREAD 1
diff --git a/arch/arm/mach-at91/include/mach/board.h b/arch/arm/mach-at91/include/mach/board.h
index ceaec6c..fd8a385 100644
--- a/arch/arm/mach-at91/include/mach/board.h
+++ b/arch/arm/mach-at91/include/mach/board.h
@@ -39,6 +39,7 @@
#include <linux/usb/atmel_usba_udc.h>
#include <linux/atmel-mci.h>
#include <sound/atmel-ac97c.h>
+#include <linux/serial.h>
/* USB Device */
struct at91_udc_data {
@@ -146,6 +147,7 @@ struct atmel_uart_data {
short use_dma_tx; /* use transmit DMA? */
short use_dma_rx; /* use receive DMA? */
void __iomem *regs; /* virtual base address, if any */
+ struct serial_rs485 rs485; /* rs485 settings */
};
extern void __init at91_add_device_serial(void);
diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 2c9bf9b..826a885 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -38,6 +38,7 @@
#include <linux/dma-mapping.h>
#include <linux/atmel_pdc.h>
#include <linux/atmel_serial.h>
+#include <linux/uaccess.h>
#include <asm/io.h>
@@ -59,6 +60,9 @@
#include <linux/serial_core.h>
+static void atmel_start_rx(struct uart_port *port);
+static void atmel_stop_rx(struct uart_port *port);
+
#ifdef CONFIG_SERIAL_ATMEL_TTYAT
/* Use device name ttyAT, major 204 and minor 154-169. This is necessary if we
@@ -93,6 +97,7 @@
#define UART_GET_BRGR(port) __raw_readl((port)->membase + ATMEL_US_BRGR)
#define UART_PUT_BRGR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_BRGR)
#define UART_PUT_RTOR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_RTOR)
+#define UART_PUT_TTGR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_TTGR)
/* PDC registers */
#define UART_PUT_PTCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_PTCR)
@@ -147,6 +152,10 @@ struct atmel_uart_port {
unsigned int irq_status_prev;
struct circ_buf rx_ring;
+
+ struct serial_rs485 rs485; /* rs485 settings */
+
+ unsigned int tx_done_mask;
};
static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];
@@ -187,6 +196,81 @@ static bool atmel_use_dma_tx(struct uart_port *port)
}
#endif
+/* Enable or disable the rs485 support */
+void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
+{
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+ unsigned long flags;
+ unsigned int mode;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ mode = UART_GET_MR(port);
+
+ /* Resetting serial mode to RS232 (0x0) */
+ mode &= ~ATMEL_US_USMODE;
+
+ atmel_port->rs485 = *rs485conf;
+
+ if (rs485conf->flags & SER_RS485_ENABLED) {
+ dev_dbg(port->dev, "Setting UART to RS485\n");
+ atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
+ UART_PUT_TTGR(port, rs485conf->delay_rts_before_send);
+ mode |= ATMEL_US_USMODE_RS485;
+ } else {
+ dev_dbg(port->dev, "Setting UART to RS232\n");
+ if (atmel_use_dma_tx(port))
+ atmel_port->tx_done_mask = ATMEL_US_ENDTX | \
+ ATMEL_US_TXBUFE;
+ else
+ atmel_port->tx_done_mask = ATMEL_US_TXRDY;
+ }
+ UART_PUT_MR(port, mode);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+
+static ssize_t show_rs485(struct device *dev, struct device_attribute *attr, \
+ char *buf)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct uart_port *port = platform_get_drvdata(pdev);
+ unsigned int current_mode;
+
+ current_mode = UART_GET_MR(port) & ATMEL_US_USMODE;
+ return snprintf(buf, PAGE_SIZE, "%u\n", current_mode);
+}
+
+static ssize_t set_rs485(struct device *dev, struct device_attribute *attr, \
+ const char *buf, size_t len)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct uart_port *port = platform_get_drvdata(pdev);
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+ struct serial_rs485 rs485conf = atmel_port->rs485;
+ unsigned int value;
+
+ if (!buf)
+ return -EINVAL;
+
+ value = !!(simple_strtoul(buf, NULL, 0));
+
+ if (value) {
+ rs485conf.flags |= SER_RS485_ENABLED;
+ /* 0x4 is the normal reset value. */
+ rs485conf.delay_rts_before_send = 0x00000004;
+ } else {
+ rs485conf.flags &= ~(SER_RS485_ENABLED);
+ }
+
+ atmel_config_rs485(port, &rs485conf);
+
+ return strnlen(buf, PAGE_SIZE);
+}
+
+static DEVICE_ATTR(rs485, 0644, show_rs485, set_rs485);
+
/*
* Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty.
*/
@@ -202,6 +286,7 @@ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
{
unsigned int control = 0;
unsigned int mode;
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
#ifdef CONFIG_ARCH_AT91RM9200
if (cpu_is_at91rm9200()) {
@@ -236,6 +321,17 @@ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
mode |= ATMEL_US_CHMODE_LOC_LOOP;
else
mode |= ATMEL_US_CHMODE_NORMAL;
+
+ /* Resetting serial mode to RS232 (0x0) */
+ mode &= ~ATMEL_US_USMODE;
+
+ if (atmel_port->rs485.flags & SER_RS485_ENABLED) {
+ dev_dbg(port->dev, "Keeping UART to RS485\n");
+ UART_PUT_TTGR(port, atmel_port->rs485.delay_rts_before_send);
+ mode |= ATMEL_US_USMODE_RS485;
+ } else {
+ dev_dbg(port->dev, "Keeping UART to RS232\n");
+ }
UART_PUT_MR(port, mode);
}
@@ -268,12 +364,17 @@ static u_int atmel_get_mctrl(struct uart_port *port)
*/
static void atmel_stop_tx(struct uart_port *port)
{
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
if (atmel_use_dma_tx(port)) {
/* disable PDC transmit */
UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
- UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
- } else
- UART_PUT_IDR(port, ATMEL_US_TXRDY);
+ }
+ /* Disable interrupts */
+ UART_PUT_IDR(port, atmel_port->tx_done_mask);
+
+ if (atmel_port->rs485.flags & SER_RS485_ENABLED)
+ atmel_start_rx(port);
}
/*
@@ -281,17 +382,39 @@ static void atmel_stop_tx(struct uart_port *port)
*/
static void atmel_start_tx(struct uart_port *port)
{
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
if (atmel_use_dma_tx(port)) {
if (UART_GET_PTSR(port) & ATMEL_PDC_TXTEN)
/* The transmitter is already running. Yes, we
really need this.*/
return;
- UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
+ if (atmel_port->rs485.flags & SER_RS485_ENABLED)
+ atmel_stop_rx(port);
+
/* re-enable PDC transmit */
UART_PUT_PTCR(port, ATMEL_PDC_TXTEN);
- } else
- UART_PUT_IER(port, ATMEL_US_TXRDY);
+ }
+ /* Enable interrupts */
+ UART_PUT_IER(port, atmel_port->tx_done_mask);
+}
+
+/*
+ * start receiving - port is in process of being opened.
+ */
+static void atmel_start_rx(struct uart_port *port)
+{
+ UART_PUT_CR(port, ATMEL_US_RSTSTA); /* reset status and receiver */
+
+ if (atmel_use_dma_rx(port)) {
+ /* enable PDC controller */
+ UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | \
+ port->read_status_mask);
+ UART_PUT_PTCR(port, ATMEL_PDC_RXTEN);
+ } else {
+ UART_PUT_IER(port, ATMEL_US_RXRDY);
+ }
}
/*
@@ -302,9 +425,11 @@ static void atmel_stop_rx(struct uart_port *port)
if (atmel_use_dma_rx(port)) {
/* disable PDC receive */
UART_PUT_PTCR(port, ATMEL_PDC_RXTDIS);
- UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
- } else
+ UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | \
+ port->read_status_mask);
+ } else {
UART_PUT_IDR(port, ATMEL_US_RXRDY);
+ }
}
/*
@@ -428,8 +553,9 @@ static void atmel_rx_chars(struct uart_port *port)
static void atmel_tx_chars(struct uart_port *port)
{
struct circ_buf *xmit = &port->state->xmit;
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
- if (port->x_char && UART_GET_CSR(port) & ATMEL_US_TXRDY) {
+ if (port->x_char && UART_GET_CSR(port) & atmel_port->tx_done_mask) {
UART_PUT_CHAR(port, port->x_char);
port->icount.tx++;
port->x_char = 0;
@@ -437,7 +563,7 @@ static void atmel_tx_chars(struct uart_port *port)
if (uart_circ_empty(xmit) || uart_tx_stopped(port))
return;
- while (UART_GET_CSR(port) & ATMEL_US_TXRDY) {
+ while (UART_GET_CSR(port) & atmel_port->tx_done_mask) {
UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
@@ -449,7 +575,8 @@ static void atmel_tx_chars(struct uart_port *port)
uart_write_wakeup(port);
if (!uart_circ_empty(xmit))
- UART_PUT_IER(port, ATMEL_US_TXRDY);
+ /* Enable interrupts */
+ UART_PUT_IER(port, atmel_port->tx_done_mask);
}
/*
@@ -501,18 +628,10 @@ atmel_handle_transmit(struct uart_port *port, unsigned int pending)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
- if (atmel_use_dma_tx(port)) {
- /* PDC transmit */
- if (pending & (ATMEL_US_ENDTX | ATMEL_US_TXBUFE)) {
- UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
- tasklet_schedule(&atmel_port->tasklet);
- }
- } else {
- /* Interrupt transmit */
- if (pending & ATMEL_US_TXRDY) {
- UART_PUT_IDR(port, ATMEL_US_TXRDY);
- tasklet_schedule(&atmel_port->tasklet);
- }
+ if (pending & atmel_port->tx_done_mask) {
+ /* Either PDC or interrupt transmission */
+ UART_PUT_IDR(port, atmel_port->tx_done_mask);
+ tasklet_schedule(&atmel_port->tasklet);
}
}
@@ -590,9 +709,15 @@ static void atmel_tx_dma(struct uart_port *port)
UART_PUT_TPR(port, pdc->dma_addr + xmit->tail);
UART_PUT_TCR(port, count);
- /* re-enable PDC transmit and interrupts */
+ /* re-enable PDC transmit */
UART_PUT_PTCR(port, ATMEL_PDC_TXTEN);
- UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
+ /* Enable interrupts */
+ UART_PUT_IER(port, atmel_port->tx_done_mask);
+ } else {
+ if (atmel_port->rs485.flags & SER_RS485_ENABLED) {
+ /* DMA done, stop TX, start RX for RS485 */
+ atmel_start_rx(port);
+ }
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
@@ -1017,6 +1142,7 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
{
unsigned long flags;
unsigned int mode, imr, quot, baud;
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
/* Get current mode register */
mode = UART_GET_MR(port) & ~(ATMEL_US_USCLKS | ATMEL_US_CHRL
@@ -1115,6 +1241,17 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
/* disable receiver and transmitter */
UART_PUT_CR(port, ATMEL_US_TXDIS | ATMEL_US_RXDIS);
+ /* Resetting serial mode to RS232 (0x0) */
+ mode &= ~ATMEL_US_USMODE;
+
+ if (atmel_port->rs485.flags & SER_RS485_ENABLED) {
+ dev_dbg(port->dev, "Keeping UART to RS485\n");
+ UART_PUT_TTGR(port, atmel_port->rs485.delay_rts_before_send);
+ mode |= ATMEL_US_USMODE_RS485;
+ } else {
+ dev_dbg(port->dev, "Keeping UART to RS232\n");
+ }
+
/* set the parity, stop bits and data size */
UART_PUT_MR(port, mode);
@@ -1231,6 +1368,30 @@ static void atmel_poll_put_char(struct uart_port *port, unsigned char ch)
}
#endif
+static int
+atmel_ioctl(struct uart_port *port, unsigned int cmd, unsigned long arg)
+{
+ struct serial_rs485 rs485conf;
+
+ switch (cmd) {
+ case TIOCSRS485:
+ if (copy_from_user(&rs485conf, (struct serial_rs485 *) arg, \
+ sizeof(rs485conf)))
+ return -EFAULT;
+
+ dev_dbg(port->dev, "enable e/o disable rs485\n");
+
+ atmel_config_rs485(port, &rs485conf);
+ break;
+
+ default:
+ return -ENOIOCTLCMD;
+ }
+ return 0;
+}
+
+
+
static struct uart_ops atmel_pops = {
.tx_empty = atmel_tx_empty,
.set_mctrl = atmel_set_mctrl,
@@ -1250,6 +1411,7 @@ static struct uart_ops atmel_pops = {
.config_port = atmel_config_port,
.verify_port = atmel_verify_port,
.pm = atmel_serial_pm,
+ .ioctl = atmel_ioctl,
#ifdef CONFIG_CONSOLE_POLL
.poll_get_char = atmel_poll_get_char,
.poll_put_char = atmel_poll_put_char,
@@ -1265,13 +1427,12 @@ static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port,
struct uart_port *port = &atmel_port->uart;
struct atmel_uart_data *data = pdev->dev.platform_data;
- port->iotype = UPIO_MEM;
- port->flags = UPF_BOOT_AUTOCONF;
- port->ops = &atmel_pops;
- port->fifosize = 1;
- port->line = pdev->id;
- port->dev = &pdev->dev;
-
+ port->iotype = UPIO_MEM;
+ port->flags = UPF_BOOT_AUTOCONF;
+ port->ops = &atmel_pops;
+ port->fifosize = 1;
+ port->line = pdev->id;
+ port->dev = &pdev->dev;
port->mapbase = pdev->resource[0].start;
port->irq = pdev->resource[1].start;
@@ -1299,8 +1460,16 @@ static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port,
atmel_port->use_dma_rx = data->use_dma_rx;
atmel_port->use_dma_tx = data->use_dma_tx;
- if (atmel_use_dma_tx(port))
+ atmel_port->rs485 = data->rs485;
+ /* Use TXEMPTY for interrupt when rs485 else TXRDY or ENDTX|TXBUFE */
+ if (atmel_port->rs485.flags & SER_RS485_ENABLED)
+ atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
+ else if (atmel_use_dma_tx(port)) {
port->fifosize = PDC_BUFFER_SIZE;
+ atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE;
+ } else {
+ atmel_port->tx_done_mask = ATMEL_US_TXRDY;
+ }
}
/*
@@ -1334,6 +1503,7 @@ static void atmel_console_putchar(struct uart_port *port, int ch)
static void atmel_console_write(struct console *co, const char *s, u_int count)
{
struct uart_port *port = &atmel_ports[co->index].uart;
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
unsigned int status, imr;
unsigned int pdc_tx;
@@ -1341,7 +1511,7 @@ static void atmel_console_write(struct console *co, const char *s, u_int count)
* First, save IMR and then disable interrupts
*/
imr = UART_GET_IMR(port);
- UART_PUT_IDR(port, ATMEL_US_RXRDY | ATMEL_US_TXRDY);
+ UART_PUT_IDR(port, ATMEL_US_RXRDY | atmel_port->tx_done_mask);
/* Store PDC transmit status and disable it */
pdc_tx = UART_GET_PTSR(port) & ATMEL_PDC_TXTEN;
@@ -1355,7 +1525,7 @@ static void atmel_console_write(struct console *co, const char *s, u_int count)
*/
do {
status = UART_GET_CSR(port);
- } while (!(status & ATMEL_US_TXRDY));
+ } while (!(status & atmel_port->tx_done_mask));
/* Restore PDC transmit status */
if (pdc_tx)
@@ -1587,7 +1757,7 @@ static int __devinit atmel_serial_probe(struct platform_device *pdev)
device_init_wakeup(&pdev->dev, 1);
platform_set_drvdata(pdev, port);
- return 0;
+ return device_create_file(&(pdev->dev), &dev_attr_rs485);
err_add_port:
kfree(port->rx_ring.buf);
@@ -1619,6 +1789,8 @@ static int __devexit atmel_serial_remove(struct platform_device *pdev)
clk_put(atmel_port->clk);
+ device_remove_file(&(pdev->dev), &dev_attr_rs485);
+
return ret;
}
--
1.6.0.4
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