From: Jon Ringle <jringle@xxxxxxxxxxxxx>
I am requesting comments on this serial driver.
I am currently having some latency issues with it where I experience
packet loss at speed of 19200.
I welcome any and all comments.
Thank you,
Jon
Signed-off-by: Jon Ringle <jringle@xxxxxxxxxxxxx>
---
drivers/tty/serial/Kconfig | 7 +
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/sc16is7xx.c | 850 +++++++++++++++++++++++++++++++++++++++
include/uapi/linux/serial_core.h | 3 +
4 files changed, 861 insertions(+)
create mode 100644 drivers/tty/serial/sc16is7xx.c
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index febd45c..c841272 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1179,6 +1179,13 @@ config SERIAL_SCCNXP_CONSOLE
help
Support for console on SCCNXP serial ports.
+config SERIAL_SC16IS7XX
+ tristate "SC16IS7xx RS485 serial support"
+ select SERIAL_CORE
+ default n
+ help
+ This selects support for SC16IS7xx for use as a RS485 serial port
+
config SERIAL_BFIN_SPORT
tristate "Blackfin SPORT emulate UART"
depends on BLACKFIN
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 3068c77..c3bac45 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -49,6 +49,7 @@ obj-$(CONFIG_SERIAL_SB1250_DUART) += sb1250-duart.o
obj-$(CONFIG_ETRAX_SERIAL) += crisv10.o
obj-$(CONFIG_SERIAL_SC26XX) += sc26xx.o
obj-$(CONFIG_SERIAL_SCCNXP) += sccnxp.o
+obj-$(CONFIG_SERIAL_SC16IS7XX) += sc16is7xx.o
obj-$(CONFIG_SERIAL_JSM) += jsm/
obj-$(CONFIG_SERIAL_TXX9) += serial_txx9.o
obj-$(CONFIG_SERIAL_VR41XX) += vr41xx_siu.o
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
new file mode 100644
index 0000000..5daed84
--- /dev/null
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -0,0 +1,850 @@
+/*
+ * The SC16IS740/750/760 is a slave I2C-bus/SPI interface to a single-channel high
+ * performance UART. The SC16IS740/750/760’s internal register set is backward-compatible
+ * with the widely used and widely popular 16C450. The SC16IS740/750/760 also provides
+ * additional advanced features such as auto hardware and software flow control, automatic
+ * RS-485 support, and software reset.
+ *
+ * Copyright (C) 2014 GridPoint
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Notes:
+ * The sc16is740 driver is used for the GPEC RS485 Half duplex communication.
+ * In the EC1K board the sc16is740 RTS line is connected to the SN65HVD1780DR chip and which
+ * is used to signal the RS485 diretion. When the RTS is low the RS485 direction is set to
+ * output from the CPU.
+ * To set the RS485 diretion we use the sc16is740 internal RS485 feature where the chip drives
+ * the RTS line when the data is written to the TX FIFO (see the spec note for the EFCR[4] bit
+ * configuration).
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio.h>
+#include <linux/platform_data/gpio-davinci.h>
+#include <linux/i2c.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/sched/rt.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/serial_reg.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/wait.h>
+
+#define DRV_VERSION "0.3"
+#define DRV_NAME "sc16is7xx"
+#define DEV_NAME "ttySC"
+#define SC16IS7XX_MAJOR 204 /* Take place of the /dev/ttySC0 SCI serial port 0 */
+#define SC16IS7XX_MINOR 8
+
+/*
+ * Software Definitions
+ */
+/* Commands sent from the uart callbacks to the work handler */
+#define SC16IS7XX_CMND_STOP_RX (0) /* Disable the RX interrupt */
+#define SC16IS7XX_CMND_START_TX (1) /* Enable the TX holding register empty interrupt */
+#define SC16IS7XX_CMND_STOP_TX (2) /* Disable the TX holding register empty interrupt */
+#define SC16IS7XX_CMND_NEW_TERMIOS (3) /* Apply new termios configuration */
+#define SC16IS7XX_CMND_BREAK_CTRL (4)
+#define SC16IS7XX_CMND_TX_RX (5)
+
+#define SC16IS7XX_CLEAR_FIFO_ON_TX /* If defined controller will clear tx fifo before it transmits chars */
+
+/*
+ * SC16IS7XX Hardware Definitions
+ */
+#define DA850_RS485_INT_PIN GPIO_TO_PIN(0,4)
+
+#define SC16IS7XX_CLK 7372800 /* crystal clock connected to the SC16IS7XX chip */
+#define SC16IS7XX_DEFAULT_BAUDRATE 19200
+
+/* General registers set */
+#define SC16IS7XX_TCR 0x06
+#define SC16IS7XX_TLR 0x07
+#define SC16IS7XX_TXLVL 0x08
+#define SC16IS7XX_RXLVL 0x09
+#define SC16IS7XX_EFCR 0x0F
+
+/* LCR / MCR configurations */
+#define UART_LCR_8N1 UART_LCR_WLEN8
+
+#define SC16IS7XX_LCRVAL UART_LCR_8N1 /* 8 data, 1 stop, no parity */
+#define SC16IS7XX_MCRVAL (UART_MCR_DTR|UART_MCR_RTS) /* clock divisor = 1,UART mode,lpback disabled,RTS/DTR are set,TCR/TLR disabled */
+
+/* SC16IS7XX Internal register address translation */
+#define REG_TO_I2C_ADDR(reg) (((reg) & 0x0f) << 3)
+
+#define SC16IS7XX_FIFO_SIZE 64 /* Rx fifo size */
+
+#define SC16IS7XX_LOAD_SIZE 64 /* Tx fifo size */
+
+struct uart_sc16is7xx_port {
+ struct uart_port port;
+
+ /* private to the driver */
+ struct i2c_client* client; /* I2C client handle */
+
+ int tx_empty; /* last TX empty bit */
+
+ unsigned long command; /* Command to the work executed from the workqueue */
+
+ struct ktermios* termios_new;
+ struct ktermios* termios_old;
+
+ int break_state;
+
+ char ier; /* cache Interrupt Enable Register to manage the interrupt from the work */
+ char lcr;
+ char fcr; /* cache the FIFO control register to hold write only values of that register */
+
+ spinlock_t lock;
+
+ /* set to 1 to make the workhandler exit as soon as possible */
+ int force_end_work;
+};
+
+static inline unsigned char sc16is7xx_read_reg(struct uart_sc16is7xx_port* up, unsigned char reg)
+{
+ int rc;
+ u8 val = 0;
+
+ u8 sc_reg = REG_TO_I2C_ADDR(reg);
+
+ rc = i2c_master_send(up->client, &sc_reg, 1);
+ if(rc < 0)
+ {
+ dev_err(&up->client->dev,"%s I2C error writing the i2c client rc = %d\n",__FUNCTION__, rc);
+ goto out;
+ }
+
+ rc = i2c_master_recv(up->client, &val, 1);
+ if(rc < 0)
+ {
+ dev_err(&up->client->dev,"%s I2C error reading from the i2c client rc = %d\n",__FUNCTION__, rc);
+ }
+
+out:
+ return val;
+}
+
+static inline void sc16is7xx_write_reg(struct uart_sc16is7xx_port *up, unsigned char reg, unsigned char value)
+{
+ int rc;
+
+ u8 msg[2];
+
+ msg[0] = REG_TO_I2C_ADDR(reg);
+ msg[1] = value;
+
+ rc = i2c_master_send(up->client, msg, 2);
+ if(rc < 0)
+ {
+ dev_err(&up->client->dev,"%s I2C error writing the i2c client rc = %d\n",__FUNCTION__, rc);
+ }
+}
+
+static void sc16is7xx_enable_irq(struct uart_sc16is7xx_port *up, int mask)
+{
+ up->ier |= mask;
+ sc16is7xx_write_reg(up, UART_IER, up->ier);
+}
+
+static void sc16is7xx_disable_irq(struct uart_sc16is7xx_port *up, int mask)
+{
+ up->ier &= ~mask;
+ sc16is7xx_write_reg(up, UART_IER, up->ier);
+}
+
+
+static void sc16is7xx_set_baudrate(struct uart_sc16is7xx_port* up, int baudrate)
+{
+ u8 lcr, ier;
+ u32 divisor;
+
+ ier = sc16is7xx_read_reg(up, UART_IER);
+ lcr = sc16is7xx_read_reg(up, UART_LCR);
+ sc16is7xx_write_reg(up, UART_IER, 0x00); // Disable interrupts
+
+ sc16is7xx_write_reg(up, SC16IS7XX_EFCR, 0x06 ); // Disable TX/RX
+
+ sc16is7xx_write_reg(up, UART_LCR, UART_LCR_CONF_MODE_B); // Open the LCR divisors for configuration
+
+ sc16is7xx_write_reg(up, UART_EFR, 0x10); // Enable enhanced features and internal clock divider
+
+ sc16is7xx_write_reg(up, UART_MCR, UART_MCR_CLKSEL|4); // Set the input clock divisor to 1
+
+ /* Get the baudrate divisor from the upper port layer */
+ divisor = uart_get_divisor(&up->port, baudrate);
+
+ sc16is7xx_write_reg(up, UART_DLL, divisor & 0xff ); // Write the new divisor
+ sc16is7xx_write_reg(up, UART_DLM, (divisor >> 8) & 0xff);
+
+ sc16is7xx_write_reg(up, UART_LCR, lcr); // Put LCR back to the normal mode
+
+ sc16is7xx_write_reg(up, SC16IS7XX_TLR, 0x0f);
+ up->fcr = UART_FCR_ENABLE_FIFO;
+ sc16is7xx_write_reg(up, UART_FCR, up->fcr); // Enable the FIFOs
+
+ sc16is7xx_write_reg(up, SC16IS7XX_EFCR, 0x10); // Enable the Rx and Tx and control the RTS (RS485_DIR) line
+
+ sc16is7xx_write_reg(up, UART_IER, ier); // Restore the interrupts configuration
+}
+
+/*
+ * The function actually delivers the Tx characters to the HW
+ */
+static void sc16is7xx_transmit_chars(struct uart_sc16is7xx_port* up)
+{
+ struct circ_buf *xmit = &up->port.state->xmit;
+ int count;
+ int chars = 0;
+
+ dev_dbg(&up->client->dev, "%s\n", __func__);
+
+ if (up->port.x_char) {
+ sc16is7xx_write_reg(up, UART_TX, up->port.x_char);
+ up->port.icount.tx++;
+ up->port.x_char = 0;
+ return;
+ }
+ if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
+ up->ier &= ~UART_IER_THRI;
+ return;
+ }
+
+ count = up->port.fifosize;
+ do {
+ sc16is7xx_write_reg(up, UART_TX, xmit->buf[xmit->tail]);
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ chars++;
+ up->port.icount.tx++;
+ if (uart_circ_empty(xmit))
+ break;
+ } while ((--count > 0) && !up->force_end_work);
+
+ dev_dbg(&up->client->dev, "%s: TX %d\n", __func__, chars);
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(&up->port);
+
+ if (uart_circ_empty(xmit)) {
+ up->ier &= ~UART_IER_THRI;
+ }
+}
+
+/*
+ * The function actually receives the characters from the HW and transfers them up to the TTY layer.
+ */
+static inline void sc16is7xx_receive_chars(struct uart_sc16is7xx_port *up, int *status)
+{
+ unsigned int ch, flag;
+ int chars = 0;
+ int max_count = 256;
+
+ dev_dbg(&up->client->dev, "%s\n", __func__);
+
+ do {
+ if (likely(*status & UART_LSR_DR)) {
+ ch = sc16is7xx_read_reg(up, UART_RX);
+ } else {
+ ch = 0xffff;
+ }
+
+ if (*status & up->port.ignore_status_mask) {
+ goto ignore_char;
+ }
+
+ flag = TTY_NORMAL;
+ up->port.icount.rx++;
+
+ if (unlikely(*status & (UART_LSR_BRK_ERROR_BITS))) {
+ /*
+ * For statistics only
+ */
+ if (*status & UART_LSR_BI) {
+ *status &= ~(UART_LSR_FE | UART_LSR_PE);
+ up->port.icount.brk++;
+ /*
+ * We do the SysRQ and SAK checking
+ * here because otherwise the break
+ * may get masked by ignore_status_mask
+ * or read_status_mask.
+ */
+ if (uart_handle_break(&up->port)) {
+ goto ignore_char;
+ }
+ } else if (*status & UART_LSR_PE) {
+ up->port.icount.parity++;
+ } else if (*status & UART_LSR_FE) {
+ up->port.icount.frame++;
+ }
+ if (*status & UART_LSR_OE) {
+ up->port.icount.overrun++;
+ }
+
+ /*
+ * Mask off conditions which should be ignored.
+ */
+ *status &= up->port.read_status_mask;
+
+ if (*status & UART_LSR_BI) {
+ flag = TTY_BREAK;
+ } else if (*status & UART_LSR_PE) {
+ flag = TTY_PARITY;
+ } else if (*status & UART_LSR_FE) {
+ flag = TTY_FRAME;
+ }
+ }
+
+ if (unlikely(0xffff == ch)) {
+ goto ignore_char;
+ }
+
+ if (uart_handle_sysrq_char(&up->port, ch)) {
+ goto ignore_char;
+ }
+
+ uart_insert_char(&up->port, *status, UART_LSR_OE, ch, flag);
+ chars++;
+
+ignore_char:
+ *status = sc16is7xx_read_reg(up, UART_LSR);
+ } while ((*status & (UART_LSR_DR | UART_LSR_BI)) && (max_count-- > 0) && !up->force_end_work);
+
+ dev_dbg(&up->client->dev, "%s RX:%d chars oe:%d\n", __func__, chars, up->port.icount.overrun);
+
+ if (chars > 0) {
+ tty_flip_buffer_push(&(up->port.state->port));
+ }
+}
+
+static void
+sc16is7xx_set_termios_work(struct uart_sc16is7xx_port *up)
+{
+ struct ktermios* termios = up->termios_new;
+ struct ktermios* old = up->termios_old;
+ unsigned long flags;
+ unsigned char cval;
+ unsigned int baud;
+
+ spin_lock_irqsave(&up->lock, flags);
+
+ switch (termios->c_cflag & CSIZE) {
+ case CS5:
+ cval = UART_LCR_WLEN5;
+ break;
+ case CS6:
+ cval = UART_LCR_WLEN6;
+ break;
+ case CS7:
+ cval = UART_LCR_WLEN7;
+ break;
+ default:
+ case CS8:
+ cval = UART_LCR_WLEN8;
+ break;
+ }
+
+ if (termios->c_cflag & CSTOPB)
+ cval |= UART_LCR_STOP;
+ if (termios->c_cflag & PARENB)
+ cval |= UART_LCR_PARITY;
+ if (!(termios->c_cflag & PARODD))
+ cval |= UART_LCR_EPAR;
+
+ sc16is7xx_write_reg(up, UART_LCR, cval);
+
+ /*
+ * Ask the core to calculate the divisor for us.
+ */
+ baud = uart_get_baud_rate(&up->port, termios, old, 9600, 115200);
+ sc16is7xx_set_baudrate(up, baud);
+
+ up->port.state->port.low_latency = 1; // Low latency since we Tx from the work queue
+
+ /*
+ * Update the per-port timeout.
+ */
+ uart_update_timeout(&up->port, termios->c_cflag, baud);
+
+ /*
+ * ignore all characters if CREAD is not set
+ */
+ if ((termios->c_cflag & CREAD) == 0)
+ up->port.ignore_status_mask |= UART_LSR_DR;
+
+ if(tty_termios_baud_rate(termios))
+ {
+ tty_termios_encode_baud_rate(termios,baud,baud);
+ }
+
+ spin_unlock_irqrestore(&up->lock, flags);
+}
+
+static void sc16is7xx_work(struct uart_sc16is7xx_port *up)
+{
+ unsigned int lsr;
+
+ up->ier = sc16is7xx_read_reg(up, UART_IER);
+
+ /* We cannot handle the interrupts while in the work queue so we disable the RX interrupt.
+ * It is ok because of during the reception of the characters we check the status of the
+ * interrupt register and process all incoming packets
+ */
+ sc16is7xx_write_reg(up, UART_IER, 0x00);
+
+ dev_dbg(&up->client->dev, "%s: start work command:%04lx ier:0x%02x\n", __func__, up->command, (int)up->ier);
+
+ if(test_and_clear_bit(SC16IS7XX_CMND_NEW_TERMIOS, &up->command)) {
+ dev_dbg(&up->client->dev, "CMND_NEW_TERMIOS\n");
+ /* User requested the changes in the Terminal Configurations */
+ sc16is7xx_set_termios_work(up);
+ }
+
+ if(test_and_clear_bit(SC16IS7XX_CMND_BREAK_CTRL, &up->command)) {
+ if (up->break_state == -1) {
+ up->lcr |= UART_LCR_SBC;
+ } else {
+ up->lcr &= ~UART_LCR_SBC;
+ }
+ sc16is7xx_write_reg(up, UART_LCR, up->lcr);
+ }
+
+ if(test_and_clear_bit(SC16IS7XX_CMND_START_TX, &up->command)) {
+ dev_dbg(&up->client->dev, "CMND_START_TX\n");
+ /* Enable the Tx holding register empty interrupt */
+ up->ier |= UART_IER_THRI;
+
+#ifdef SC16IS7XX_CLEAR_FIFO_ON_TX
+ /* Clear Tx Fifo to remove the junk characters if any */
+ if(up->fcr & UART_FCR_ENABLE_FIFO) {
+ /* Fifo is enabled */
+ sc16is7xx_write_reg(up, UART_FCR, up->fcr & UART_FCR_CLEAR_XMIT);
+ dev_dbg(&up->client->dev, "Clear FIFO\n");
+ }
+#endif
+ }
+
+ if(test_and_clear_bit(SC16IS7XX_CMND_STOP_TX, &up->command)) {
+ dev_dbg(&up->client->dev, "CMND_STOP_TX\n");
+ /* Disable the Tx holding register interrupt */
+ up->ier &= ~UART_IER_THRI;
+ }
+
+ if(test_and_clear_bit(SC16IS7XX_CMND_STOP_RX, &up->command)) {
+ dev_dbg(&up->client->dev, "CMND_STOP_RX\n");
+ /* User requested to stop the RX interrupt so we clear the interrupt enable register */
+ up->ier &= ~UART_IER_RDI;
+ }
+
+ clear_bit(SC16IS7XX_CMND_TX_RX, &up->command);
+ lsr = sc16is7xx_read_reg(up, UART_LSR);
+ if ((lsr & (UART_LSR_DR | UART_LSR_BI)) && (up->ier & UART_IER_RDI)) {
+ sc16is7xx_receive_chars(up, &lsr);
+ if (lsr & (UART_LSR_DR | UART_LSR_BI)) {
+ /* There is more to receive */
+ set_bit(SC16IS7XX_CMND_TX_RX, &up->command);
+ }
+ }
+
+ if ((lsr & UART_LSR_THRE) && (up->ier & UART_IER_THRI)) {
+ sc16is7xx_transmit_chars(up);
+ }
+
+ if(sc16is7xx_read_reg(up, UART_LSR) & UART_LSR_THRE)
+ {
+ dev_dbg(&up->client->dev, "%s: TX_EMPTY\n", __FUNCTION__);
+ up->tx_empty = TIOCSER_TEMT;
+ }
+ else
+ {
+ dev_dbg(&up->client->dev, "%s: TX_NOT_EMPTY\n", __FUNCTION__);
+ up->tx_empty = 0; /* port is not ready to accept the new TX characters */
+ }
+
+ dev_dbg(&up->client->dev, "%s: end work ier 0x%02X\n", __func__, (int)up->ier);
+
+ sc16is7xx_write_reg(up, UART_IER, up->ier); /* Restore the interrupts */
+}
+
+static irqreturn_t sc16is7xx_ist(int irq, void* dev_id)
+{
+ struct uart_sc16is7xx_port* up = (struct uart_sc16is7xx_port *)dev_id;
+ unsigned long flags;
+
+ spin_lock_irqsave(&up->lock, flags);
+ sc16is7xx_work(up);
+ spin_unlock_irqrestore(&up->lock, flags);
+
+ return IRQ_HANDLED;
+}
+
+static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
+{
+ struct uart_sc16is7xx_port *up = (struct uart_sc16is7xx_port *)port;
+
+ dev_dbg(&up->client->dev, "%s:(%d)\n", __FUNCTION__, up->tx_empty);
+ return up->tx_empty;
+}
+
+static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+ /* Just a placeholder. We do not have modem control lines in our RS485 port */
+}
+
+static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
+{
+ /* Just a placeholder. We do not have modem control lines in our RS485 port */
+ return TIOCM_CAR | TIOCM_RNG | TIOCM_DSR | TIOCM_CTS;
+}
+
+static void sc16is7xx_start_tx(struct uart_port *port)
+{
+ struct uart_sc16is7xx_port *up = (struct uart_sc16is7xx_port *)port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&up->lock, flags);
+
+ set_bit(SC16IS7XX_CMND_START_TX, &up->command);
+ dev_dbg(&up->client->dev, "%s\n", __func__);
+ sc16is7xx_work(up);
+
+ spin_unlock_irqrestore(&up->lock, flags);
+}
+
+static void sc16is7xx_stop_rx(struct uart_port *port)
+{
+ struct uart_sc16is7xx_port *up = (struct uart_sc16is7xx_port *)port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&up->lock, flags);
+
+ set_bit(SC16IS7XX_CMND_STOP_RX, &up->command);
+ dev_dbg(&up->client->dev, "%s\n", __func__);
+ sc16is7xx_work(up);
+
+ spin_unlock_irqrestore(&up->lock, flags);
+}
+
+static void sc16is7xx_stop_tx(struct uart_port *port)
+{
+ struct uart_sc16is7xx_port *up = (struct uart_sc16is7xx_port *)port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&up->lock, flags);
+
+ set_bit(SC16IS7XX_CMND_STOP_TX, &up->command);
+ dev_dbg(&up->client->dev, "%s\n", __func__);
+ sc16is7xx_work(up);
+
+ spin_unlock_irqrestore(&up->lock, flags);
+}
+
+static void sc16is7xxs_enable_ms(struct uart_port* port)
+{
+ /* Do nothing */
+}
+
+static void sc16is7xx_break_ctl(struct uart_port *port, int break_state)
+{
+ struct uart_sc16is7xx_port *up = (struct uart_sc16is7xx_port *)port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&up->lock, flags);
+
+ dev_dbg(&up->client->dev, "%s:(%d)\n", __FUNCTION__, break_state);
+ up->break_state = break_state;
+ set_bit(SC16IS7XX_CMND_BREAK_CTRL, &up->command);
+ sc16is7xx_work(up);
+
+ spin_unlock_irqrestore(&up->lock, flags);
+}
+
+static void sc16is7xx_shutdown(struct uart_port *port)
+{
+ struct uart_sc16is7xx_port *up = (struct uart_sc16is7xx_port *)port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&up->lock, flags);
+
+ dev_dbg(&up->client->dev, "%s\n", __func__);
+
+ /*
+ * Disable interrupts from this port
+ */
+ sc16is7xx_disable_irq(up, UART_IER_THRI | UART_IER_RDI);
+
+ /*
+ * Disable break condition and FIFOs
+ */
+ sc16is7xx_write_reg(up, UART_LCR, sc16is7xx_read_reg(up, UART_LCR) & ~UART_LCR_SBC);
+ sc16is7xx_write_reg(up, UART_FCR, UART_FCR_ENABLE_FIFO |
+ UART_FCR_CLEAR_RCVR |
+ UART_FCR_CLEAR_XMIT);
+ sc16is7xx_write_reg(up, UART_FCR, 0);
+
+ spin_unlock_irqrestore(&up->lock, flags);
+
+ dev_dbg(&up->client->dev, "%s done\n", __func__);
+}
+
+static int sc16is7xx_startup(struct uart_port *port)
+{
+ struct uart_sc16is7xx_port *up = (struct uart_sc16is7xx_port *)port;
+ unsigned long flags;
+
+ dev_dbg(&up->client->dev, "%s\n", __func__);
+
+ spin_lock_irqsave(&up->lock, flags);
+
+ up->force_end_work = 0;
+ up->command = 0;
+ up->break_state = -1;
+ up->tx_empty = TIOCSER_TEMT;
+
+ // Disable IRQs to configure
+ sc16is7xx_write_reg(up, UART_IER, 0);
+
+ /*
+ * Now, initialize the UART
+ */
+ sc16is7xx_write_reg(up, UART_LCR, UART_LCR_8N1);
+
+ /*
+ * Clear the FIFO buffers and disable them.
+ * (they will be reenabled in set_termios())
+ */
+ while(sc16is7xx_read_reg(up, UART_LSR) & (UART_LSR_DR | UART_LSR_BI))
+ {
+ /* Empty the RX holding register to prevent printing stale characters on the screen */
+ sc16is7xx_read_reg(up, UART_RX);
+ }
+
+ /*
+ * Finally, enable interrupts.
+ */
+ sc16is7xx_enable_irq(up, UART_IER_RDI);
+
+ spin_unlock_irqrestore(&up->lock, flags);
+ return 0;
+}
+
+static void
+sc16is7xx_set_termios(struct uart_port* port, struct ktermios* termios, struct ktermios* old)
+{
+ struct uart_sc16is7xx_port * up = (struct uart_sc16is7xx_port *)port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&up->lock, flags);
+
+ up->termios_new = termios;
+ up->termios_old = old;
+
+ set_bit(SC16IS7XX_CMND_NEW_TERMIOS, &up->command);
+
+ sc16is7xx_work(up);
+
+ spin_unlock_irqrestore(&up->lock, flags);
+}
+
+static const char *sc16is7xx_type(struct uart_port *port)
+{
+ struct uart_sc16is7xx_port *up = (struct uart_sc16is7xx_port *)port;
+ return up->port.type == PORT_SC16IS7XX ? DEV_NAME : NULL;
+}
+
+static void sc16is7xx_release_port(struct uart_port *port)
+{
+}
+
+static int sc16is7xx_request_port(struct uart_port *port)
+{
+ return 0;
+}
+
+static void sc16is7xx_config_port(struct uart_port *port, int flags)
+{
+ struct uart_sc16is7xx_port *up = (struct uart_sc16is7xx_port *)port;
+
+ if (flags & UART_CONFIG_TYPE)
+ up->port.type = PORT_SC16IS7XX;
+}
+
+static int sc16is7xx_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+ int ret = -EINVAL;
+
+ if (ser->type == PORT_UNKNOWN || ser->type == PORT_SC16IS7XX)
+ ret = 0;
+ return ret;
+}
+
+
+static struct uart_ops sc16is7xx_ops = {
+ .tx_empty = sc16is7xx_tx_empty,
+ .set_mctrl = sc16is7xx_set_mctrl,
+ .get_mctrl = sc16is7xx_get_mctrl,
+ .stop_tx = sc16is7xx_stop_tx,
+ .start_tx = sc16is7xx_start_tx,
+ .stop_rx = sc16is7xx_stop_rx,
+ .enable_ms = sc16is7xxs_enable_ms,
+ .break_ctl = sc16is7xx_break_ctl,
+ .startup = sc16is7xx_startup,
+ .shutdown = sc16is7xx_shutdown,
+ .set_termios = sc16is7xx_set_termios,
+ .type = sc16is7xx_type,
+ .release_port = sc16is7xx_release_port,
+ .request_port = sc16is7xx_request_port,
+ .config_port = sc16is7xx_config_port,
+ .verify_port = sc16is7xx_verify_port,
+};
+
+static struct uart_driver sc16is7xx_uart_driver = {
+ .owner = THIS_MODULE,
+ .driver_name = DRV_NAME,
+ .dev_name = DEV_NAME,
+ .major = SC16IS7XX_MAJOR,
+ .minor = SC16IS7XX_MINOR,
+ .nr = 1,
+};
+static int uart_driver_registered = 0;
+
+static int sc16is7xx_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int retval;
+ struct uart_sc16is7xx_port* up = NULL; /* user port */
+
+ if (!uart_driver_registered) {
+ retval = uart_register_driver(&sc16is7xx_uart_driver);
+ if (retval) {
+ printk(KERN_ERR "Couldn't register sc16is7xx uart driver\n");
+ return retval;
+ }
+ uart_driver_registered = 1;
+ }
+
+ up = kzalloc(sizeof(struct uart_sc16is7xx_port), GFP_KERNEL);
+ if (!up) {
+ dev_warn(&client->dev,
+ "kmalloc for sc16is7xx structure failed!\n");
+ return -ENOMEM;
+ }
+
+ /* First check if adaptor is OK and it supports our I2C functionality */
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ {
+ dev_err(&client->dev,"Can't find the sc16is7xx chip\n");
+ retval = -ENODEV;
+ goto exit;
+ }
+
+ dev_info(&client->dev,"chip found, driver version " DRV_VERSION "\n");
+
+ /* Configure the GPIO IRQ line */
+ retval = gpio_request(DA850_RS485_INT_PIN, "SC16IS7xx INT");
+
+ if(retval)
+ {
+ dev_err(&client->dev,"Can't request gpio interrupt pin \n");
+ retval = -EIO;
+ goto exit;
+ }
+
+ gpio_direction_input(DA850_RS485_INT_PIN); // Set GPIO IRQ pin to be input
+
+ up->client = client;
+
+ dev_dbg(&client->dev, "%s: adding port\n", __func__);
+ up->port.irq = gpio_to_irq(DA850_RS485_INT_PIN);
+ up->port.uartclk = SC16IS7XX_CLK;
+ up->port.fifosize = SC16IS7XX_FIFO_SIZE;
+ up->port.ops = &sc16is7xx_ops;
+ up->port.iotype = UPIO_PORT;
+ up->port.flags = UPF_FIXED_TYPE | UPF_FIXED_PORT;
+ up->port.line = 0;
+ up->port.type = PORT_SC16IS7XX;
+ up->port.dev = &client->dev;
+
+ retval = uart_add_one_port(&sc16is7xx_uart_driver, &up->port);
+ if (retval < 0)
+ dev_warn(&client->dev,
+ "uart_add_one_port failed with error %d\n",
+ retval);
+
+ i2c_set_clientdata(client,up);
+
+ /* Disable interrupts */
+ up->ier = 0;
+ sc16is7xx_write_reg(up, UART_IER, 0);
+
+ if (devm_request_threaded_irq(&up->client->dev, up->port.irq,
+ NULL, sc16is7xx_ist,
+ IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+ DRV_NAME, up) < 0) {
+ dev_err(&up->client->dev, "cannot allocate irq %d\n", up->port.irq);
+ return -EBUSY;
+ }
+
+ return 0;
+
+exit:
+ kfree(up);
+ return retval;
+}
+
+static int sc16is7xx_remove(struct i2c_client *client)
+{
+ struct uart_sc16is7xx_port *up = i2c_get_clientdata(client);
+
+ if(!uart_driver_registered)
+ {
+ return 0;
+ }
+
+ devm_free_irq(&client->dev, up->port.irq, up);
+
+ /* find out the index for the chip we are removing */
+ dev_dbg(&client->dev, "%s: removing port\n", __func__);
+ uart_remove_one_port(&sc16is7xx_uart_driver, &up->port);
+ kfree(up);
+ up = NULL;
+
+ pr_debug("removing sc16is7xx driver\n");
+ uart_unregister_driver(&sc16is7xx_uart_driver);
+
+ uart_driver_registered = 0;
+
+ return 0;
+}
+
+static const struct i2c_device_id sc16is7xx_i2c_id[] = {
+ { "sc16is7xx",0},
+ { }
+};
+
+static struct i2c_driver sc16is7xx_driver = {
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ },
+ .probe = sc16is7xx_probe,
+ .remove = sc16is7xx_remove,
+ .id_table = sc16is7xx_i2c_id,
+};
+
+module_i2c_driver(sc16is7xx_driver);
+
+MODULE_DESCRIPTION("SC16IS7xx RS485 Port Driver");
+MODULE_AUTHOR("Jon Ringle <jringle@xxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+MODULE_ALIAS("i2c:sc16is7xx");
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index b47dba2..a37c79a 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -238,4 +238,7 @@
/* Tilera TILE-Gx UART */
#define PORT_TILEGX 106
+/* SC16IS74xx */
+#define PORT_SC16IS7XX 107
+
#endif /* _UAPILINUX_SERIAL_CORE_H */
--
1.8.5.4
--
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