]> git.karo-electronics.de Git - linux-beck.git/commitdiff
V4L/DVB: staging/lirc: add lirc_serial driver
authorJarod Wilson <jarod@redhat.com>
Mon, 26 Jul 2010 23:31:45 +0000 (20:31 -0300)
committerMauro Carvalho Chehab <mchehab@redhat.com>
Mon, 2 Aug 2010 19:43:29 +0000 (16:43 -0300)
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
drivers/staging/lirc/lirc_serial.c [new file with mode: 0644]

diff --git a/drivers/staging/lirc/lirc_serial.c b/drivers/staging/lirc/lirc_serial.c
new file mode 100644 (file)
index 0000000..d2ea3f0
--- /dev/null
@@ -0,0 +1,1313 @@
+/*
+ * lirc_serial.c
+ *
+ * lirc_serial - Device driver that records pulse- and pause-lengths
+ *            (space-lengths) between DDCD event on a serial port.
+ *
+ * Copyright (C) 1996,97 Ralph Metzler <rjkm@thp.uni-koeln.de>
+ * Copyright (C) 1998 Trent Piepho <xyzzy@u.washington.edu>
+ * Copyright (C) 1998 Ben Pfaff <blp@gnu.org>
+ * Copyright (C) 1999 Christoph Bartelmus <lirc@bartelmus.de>
+ * Copyright (C) 2007 Andrei Tanas <andrei@tanas.ca> (suspend/resume support)
+ *  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.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+/*
+ * Steve's changes to improve transmission fidelity:
+ *   - for systems with the rdtsc instruction and the clock counter, a
+ *     send_pule that times the pulses directly using the counter.
+ *     This means that the LIRC_SERIAL_TRANSMITTER_LATENCY fudge is
+ *     not needed. Measurement shows very stable waveform, even where
+ *     PCI activity slows the access to the UART, which trips up other
+ *     versions.
+ *   - For other system, non-integer-microsecond pulse/space lengths,
+ *     done using fixed point binary. So, much more accurate carrier
+ *     frequency.
+ *   - fine tuned transmitter latency, taking advantage of fractional
+ *     microseconds in previous change
+ *   - Fixed bug in the way transmitter latency was accounted for by
+ *     tuning the pulse lengths down - the send_pulse routine ignored
+ *     this overhead as it timed the overall pulse length - so the
+ *     pulse frequency was right but overall pulse length was too
+ *     long. Fixed by accounting for latency on each pulse/space
+ *     iteration.
+ *
+ * Steve Davies <steve@daviesfam.org>  July 2001
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/serial_reg.h>
+#include <linux/time.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#include <linux/mm.h>
+#include <linux/delay.h>
+#include <linux/poll.h>
+#include <linux/platform_device.h>
+
+#include <asm/system.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/fcntl.h>
+#include <linux/spinlock.h>
+
+#ifdef CONFIG_LIRC_SERIAL_NSLU2
+#include <asm/hardware.h>
+#endif
+/* From Intel IXP42X Developer's Manual (#252480-005): */
+/* ftp://download.intel.com/design/network/manuals/25248005.pdf */
+#define UART_IE_IXP42X_UUE   0x40 /* IXP42X UART Unit enable */
+#define UART_IE_IXP42X_RTOIE 0x10 /* IXP42X Receiver Data Timeout int.enable */
+
+#include <media/lirc.h>
+#include <media/lirc_dev.h>
+
+#define LIRC_DRIVER_NAME "lirc_serial"
+
+struct lirc_serial {
+       int signal_pin;
+       int signal_pin_change;
+       u8 on;
+       u8 off;
+       long (*send_pulse)(unsigned long length);
+       void (*send_space)(long length);
+       int features;
+       spinlock_t lock;
+};
+
+#define LIRC_HOMEBREW          0
+#define LIRC_IRDEO             1
+#define LIRC_IRDEO_REMOTE      2
+#define LIRC_ANIMAX            3
+#define LIRC_IGOR              4
+#define LIRC_NSLU2             5
+
+/*** module parameters ***/
+static int type;
+static int io;
+static int irq;
+static int iommap;
+static int ioshift;
+static int softcarrier = 1;
+static int share_irq;
+static int debug;
+static int sense = -1; /* -1 = auto, 0 = active high, 1 = active low */
+static int txsense;    /* 0 = active high, 1 = active low */
+
+#define dprintk(fmt, args...)                                  \
+       do {                                                    \
+               if (debug)                                      \
+                       printk(KERN_DEBUG LIRC_DRIVER_NAME ": " \
+                              fmt, ## args);                   \
+       } while (0)
+
+/* forward declarations */
+static long send_pulse_irdeo(unsigned long length);
+static long send_pulse_homebrew(unsigned long length);
+static void send_space_irdeo(long length);
+static void send_space_homebrew(long length);
+
+static struct lirc_serial hardware[] = {
+       [LIRC_HOMEBREW] = {
+               .signal_pin        = UART_MSR_DCD,
+               .signal_pin_change = UART_MSR_DDCD,
+               .on  = (UART_MCR_RTS | UART_MCR_OUT2 | UART_MCR_DTR),
+               .off = (UART_MCR_RTS | UART_MCR_OUT2),
+               .send_pulse = send_pulse_homebrew,
+               .send_space = send_space_homebrew,
+#ifdef CONFIG_LIRC_SERIAL_TRANSMITTER
+               .features    = (LIRC_CAN_SET_SEND_DUTY_CYCLE |
+                               LIRC_CAN_SET_SEND_CARRIER |
+                               LIRC_CAN_SEND_PULSE | LIRC_CAN_REC_MODE2)
+#else
+               .features    = LIRC_CAN_REC_MODE2
+#endif
+       },
+
+       [LIRC_IRDEO] = {
+               .signal_pin        = UART_MSR_DSR,
+               .signal_pin_change = UART_MSR_DDSR,
+               .on  = UART_MCR_OUT2,
+               .off = (UART_MCR_RTS | UART_MCR_DTR | UART_MCR_OUT2),
+               .send_pulse  = send_pulse_irdeo,
+               .send_space  = send_space_irdeo,
+               .features    = (LIRC_CAN_SET_SEND_DUTY_CYCLE |
+                               LIRC_CAN_SEND_PULSE | LIRC_CAN_REC_MODE2)
+       },
+
+       [LIRC_IRDEO_REMOTE] = {
+               .signal_pin        = UART_MSR_DSR,
+               .signal_pin_change = UART_MSR_DDSR,
+               .on  = (UART_MCR_RTS | UART_MCR_DTR | UART_MCR_OUT2),
+               .off = (UART_MCR_RTS | UART_MCR_DTR | UART_MCR_OUT2),
+               .send_pulse  = send_pulse_irdeo,
+               .send_space  = send_space_irdeo,
+               .features    = (LIRC_CAN_SET_SEND_DUTY_CYCLE |
+                               LIRC_CAN_SEND_PULSE | LIRC_CAN_REC_MODE2)
+       },
+
+       [LIRC_ANIMAX] = {
+               .signal_pin        = UART_MSR_DCD,
+               .signal_pin_change = UART_MSR_DDCD,
+               .on  = 0,
+               .off = (UART_MCR_RTS | UART_MCR_DTR | UART_MCR_OUT2),
+               .send_pulse = NULL,
+               .send_space = NULL,
+               .features   = LIRC_CAN_REC_MODE2
+       },
+
+       [LIRC_IGOR] = {
+               .signal_pin        = UART_MSR_DSR,
+               .signal_pin_change = UART_MSR_DDSR,
+               .on  = (UART_MCR_RTS | UART_MCR_OUT2 | UART_MCR_DTR),
+               .off = (UART_MCR_RTS | UART_MCR_OUT2),
+               .send_pulse = send_pulse_homebrew,
+               .send_space = send_space_homebrew,
+#ifdef CONFIG_LIRC_SERIAL_TRANSMITTER
+               .features    = (LIRC_CAN_SET_SEND_DUTY_CYCLE |
+                               LIRC_CAN_SET_SEND_CARRIER |
+                               LIRC_CAN_SEND_PULSE | LIRC_CAN_REC_MODE2)
+#else
+               .features    = LIRC_CAN_REC_MODE2
+#endif
+       },
+
+#ifdef CONFIG_LIRC_SERIAL_NSLU2
+       /*
+        * Modified Linksys Network Storage Link USB 2.0 (NSLU2):
+        * We receive on CTS of the 2nd serial port (R142,LHS), we
+        * transmit with a IR diode between GPIO[1] (green status LED),
+        * and ground (Matthias Goebl <matthias.goebl@goebl.net>).
+        * See also http://www.nslu2-linux.org for this device
+        */
+       [LIRC_NSLU2] = {
+               .signal_pin        = UART_MSR_CTS,
+               .signal_pin_change = UART_MSR_DCTS,
+               .on  = (UART_MCR_RTS | UART_MCR_OUT2 | UART_MCR_DTR),
+               .off = (UART_MCR_RTS | UART_MCR_OUT2),
+               .send_pulse = send_pulse_homebrew,
+               .send_space = send_space_homebrew,
+#ifdef CONFIG_LIRC_SERIAL_TRANSMITTER
+               .features    = (LIRC_CAN_SET_SEND_DUTY_CYCLE |
+                               LIRC_CAN_SET_SEND_CARRIER |
+                               LIRC_CAN_SEND_PULSE | LIRC_CAN_REC_MODE2)
+#else
+               .features    = LIRC_CAN_REC_MODE2
+#endif
+       },
+#endif
+
+};
+
+#define RS_ISR_PASS_LIMIT 256
+
+/*
+ * A long pulse code from a remote might take up to 300 bytes.  The
+ * daemon should read the bytes as soon as they are generated, so take
+ * the number of keys you think you can push before the daemon runs
+ * and multiply by 300.  The driver will warn you if you overrun this
+ * buffer.  If you have a slow computer or non-busmastering IDE disks,
+ * maybe you will need to increase this.
+ */
+
+/* This MUST be a power of two!  It has to be larger than 1 as well. */
+
+#define RBUF_LEN 256
+
+static struct timeval lasttv = {0, 0};
+
+static struct lirc_buffer rbuf;
+
+static unsigned int freq = 38000;
+static unsigned int duty_cycle = 50;
+
+/* Initialized in init_timing_params() */
+static unsigned long period;
+static unsigned long pulse_width;
+static unsigned long space_width;
+
+#if defined(__i386__)
+/*
+ * From:
+ * Linux I/O port programming mini-HOWTO
+ * Author: Riku Saikkonen <Riku.Saikkonen@hut.fi>
+ * v, 28 December 1997
+ *
+ * [...]
+ * Actually, a port I/O instruction on most ports in the 0-0x3ff range
+ * takes almost exactly 1 microsecond, so if you're, for example, using
+ * the parallel port directly, just do additional inb()s from that port
+ * to delay.
+ * [...]
+ */
+/* transmitter latency 1.5625us 0x1.90 - this figure arrived at from
+ * comment above plus trimming to match actual measured frequency.
+ * This will be sensitive to cpu speed, though hopefully most of the 1.5us
+ * is spent in the uart access.  Still - for reference test machine was a
+ * 1.13GHz Athlon system - Steve
+ */
+
+/*
+ * changed from 400 to 450 as this works better on slower machines;
+ * faster machines will use the rdtsc code anyway
+ */
+#define LIRC_SERIAL_TRANSMITTER_LATENCY 450
+
+#else
+
+/* does anybody have information on other platforms ? */
+/* 256 = 1<<8 */
+#define LIRC_SERIAL_TRANSMITTER_LATENCY 256
+
+#endif  /* __i386__ */
+/*
+ * FIXME: should we be using hrtimers instead of this
+ * LIRC_SERIAL_TRANSMITTER_LATENCY nonsense?
+ */
+
+/* fetch serial input packet (1 byte) from register offset */
+static u8 sinp(int offset)
+{
+       if (iommap != 0)
+               /* the register is memory-mapped */
+               offset <<= ioshift;
+
+       return inb(io + offset);
+}
+
+/* write serial output packet (1 byte) of value to register offset */
+static void soutp(int offset, u8 value)
+{
+       if (iommap != 0)
+               /* the register is memory-mapped */
+               offset <<= ioshift;
+
+       outb(value, io + offset);
+}
+
+static void on(void)
+{
+#ifdef CONFIG_LIRC_SERIAL_NSLU2
+       /*
+        * On NSLU2, we put the transmit diode between the output of the green
+        * status LED and ground
+        */
+       if (type == LIRC_NSLU2) {
+               gpio_line_set(NSLU2_LED_GRN, IXP4XX_GPIO_LOW);
+               return;
+       }
+#endif
+       if (txsense)
+               soutp(UART_MCR, hardware[type].off);
+       else
+               soutp(UART_MCR, hardware[type].on);
+}
+
+static void off(void)
+{
+#ifdef CONFIG_LIRC_SERIAL_NSLU2
+       if (type == LIRC_NSLU2) {
+               gpio_line_set(NSLU2_LED_GRN, IXP4XX_GPIO_HIGH);
+               return;
+       }
+#endif
+       if (txsense)
+               soutp(UART_MCR, hardware[type].on);
+       else
+               soutp(UART_MCR, hardware[type].off);
+}
+
+#ifndef MAX_UDELAY_MS
+#define MAX_UDELAY_US 5000
+#else
+#define MAX_UDELAY_US (MAX_UDELAY_MS*1000)
+#endif
+
+static void safe_udelay(unsigned long usecs)
+{
+       while (usecs > MAX_UDELAY_US) {
+               udelay(MAX_UDELAY_US);
+               usecs -= MAX_UDELAY_US;
+       }
+       udelay(usecs);
+}
+
+#ifdef USE_RDTSC
+/*
+ * This is an overflow/precision juggle, complicated in that we can't
+ * do long long divide in the kernel
+ */
+
+/*
+ * When we use the rdtsc instruction to measure clocks, we keep the
+ * pulse and space widths as clock cycles.  As this is CPU speed
+ * dependent, the widths must be calculated in init_port and ioctl
+ * time
+ */
+
+/* So send_pulse can quickly convert microseconds to clocks */
+static unsigned long conv_us_to_clocks;
+
+static int init_timing_params(unsigned int new_duty_cycle,
+               unsigned int new_freq)
+{
+       unsigned long long loops_per_sec, work;
+
+       duty_cycle = new_duty_cycle;
+       freq = new_freq;
+
+       loops_per_sec = current_cpu_data.loops_per_jiffy;
+       loops_per_sec *= HZ;
+
+       /* How many clocks in a microsecond?, avoiding long long divide */
+       work = loops_per_sec;
+       work *= 4295;  /* 4295 = 2^32 / 1e6 */
+       conv_us_to_clocks = (work >> 32);
+
+       /*
+        * Carrier period in clocks, approach good up to 32GHz clock,
+        * gets carrier frequency within 8Hz
+        */
+       period = loops_per_sec >> 3;
+       period /= (freq >> 3);
+
+       /* Derive pulse and space from the period */
+       pulse_width = period * duty_cycle / 100;
+       space_width = period - pulse_width;
+       dprintk("in init_timing_params, freq=%d, duty_cycle=%d, "
+               "clk/jiffy=%ld, pulse=%ld, space=%ld, "
+               "conv_us_to_clocks=%ld\n",
+               freq, duty_cycle, current_cpu_data.loops_per_jiffy,
+               pulse_width, space_width, conv_us_to_clocks);
+       return 0;
+}
+#else /* ! USE_RDTSC */
+static int init_timing_params(unsigned int new_duty_cycle,
+               unsigned int new_freq)
+{
+/*
+ * period, pulse/space width are kept with 8 binary places -
+ * IE multiplied by 256.
+ */
+       if (256 * 1000000L / new_freq * new_duty_cycle / 100 <=
+           LIRC_SERIAL_TRANSMITTER_LATENCY)
+               return -EINVAL;
+       if (256 * 1000000L / new_freq * (100 - new_duty_cycle) / 100 <=
+           LIRC_SERIAL_TRANSMITTER_LATENCY)
+               return -EINVAL;
+       duty_cycle = new_duty_cycle;
+       freq = new_freq;
+       period = 256 * 1000000L / freq;
+       pulse_width = period * duty_cycle / 100;
+       space_width = period - pulse_width;
+       dprintk("in init_timing_params, freq=%d pulse=%ld, "
+               "space=%ld\n", freq, pulse_width, space_width);
+       return 0;
+}
+#endif /* USE_RDTSC */
+
+
+/* return value: space length delta */
+
+static long send_pulse_irdeo(unsigned long length)
+{
+       long rawbits, ret;
+       int i;
+       unsigned char output;
+       unsigned char chunk, shifted;
+
+       /* how many bits have to be sent ? */
+       rawbits = length * 1152 / 10000;
+       if (duty_cycle > 50)
+               chunk = 3;
+       else
+               chunk = 1;
+       for (i = 0, output = 0x7f; rawbits > 0; rawbits -= 3) {
+               shifted = chunk << (i * 3);
+               shifted >>= 1;
+               output &= (~shifted);
+               i++;
+               if (i == 3) {
+                       soutp(UART_TX, output);
+                       while (!(sinp(UART_LSR) & UART_LSR_THRE))
+                               ;
+                       output = 0x7f;
+                       i = 0;
+               }
+       }
+       if (i != 0) {
+               soutp(UART_TX, output);
+               while (!(sinp(UART_LSR) & UART_LSR_TEMT))
+                       ;
+       }
+
+       if (i == 0)
+               ret = (-rawbits) * 10000 / 1152;
+       else
+               ret = (3 - i) * 3 * 10000 / 1152 + (-rawbits) * 10000 / 1152;
+
+       return ret;
+}
+
+#ifdef USE_RDTSC
+/* Version that uses Pentium rdtsc instruction to measure clocks */
+
+/*
+ * This version does sub-microsecond timing using rdtsc instruction,
+ * and does away with the fudged LIRC_SERIAL_TRANSMITTER_LATENCY
+ * Implicitly i586 architecture...  - Steve
+ */
+
+static long send_pulse_homebrew_softcarrier(unsigned long length)
+{
+       int flag;
+       unsigned long target, start, now;
+
+       /* Get going quick as we can */
+       rdtscl(start);
+       on();
+       /* Convert length from microseconds to clocks */
+       length *= conv_us_to_clocks;
+       /* And loop till time is up - flipping at right intervals */
+       now = start;
+       target = pulse_width;
+       flag = 1;
+       /*
+        * FIXME: This looks like a hard busy wait, without even an occasional,
+        * polite, cpu_relax() call.  There's got to be a better way?
+        *
+        * The i2c code has the result of a lot of bit-banging work, I wonder if
+        * there's something there which could be helpful here.
+        */
+       while ((now - start) < length) {
+               /* Delay till flip time */
+               do {
+                       rdtscl(now);
+               } while ((now - start) < target);
+
+               /* flip */
+               if (flag) {
+                       rdtscl(now);
+                       off();
+                       target += space_width;
+               } else {
+                       rdtscl(now); on();
+                       target += pulse_width;
+               }
+               flag = !flag;
+       }
+       rdtscl(now);
+       return ((now - start) - length) / conv_us_to_clocks;
+}
+#else /* ! USE_RDTSC */
+/* Version using udelay() */
+
+/*
+ * here we use fixed point arithmetic, with 8
+ * fractional bits.  that gets us within 0.1% or so of the right average
+ * frequency, albeit with some jitter in pulse length - Steve
+ */
+
+/* To match 8 fractional bits used for pulse/space length */
+
+static long send_pulse_homebrew_softcarrier(unsigned long length)
+{
+       int flag;
+       unsigned long actual, target, d;
+       length <<= 8;
+
+       actual = 0; target = 0; flag = 0;
+       while (actual < length) {
+               if (flag) {
+                       off();
+                       target += space_width;
+               } else {
+                       on();
+                       target += pulse_width;
+               }
+               d = (target - actual -
+                    LIRC_SERIAL_TRANSMITTER_LATENCY + 128) >> 8;
+               /*
+                * Note - we've checked in ioctl that the pulse/space
+                * widths are big enough so that d is > 0
+                */
+               udelay(d);
+               actual += (d << 8) + LIRC_SERIAL_TRANSMITTER_LATENCY;
+               flag = !flag;
+       }
+       return (actual-length) >> 8;
+}
+#endif /* USE_RDTSC */
+
+static long send_pulse_homebrew(unsigned long length)
+{
+       if (length <= 0)
+               return 0;
+
+       if (softcarrier)
+               return send_pulse_homebrew_softcarrier(length);
+       else {
+               on();
+               safe_udelay(length);
+               return 0;
+       }
+}
+
+static void send_space_irdeo(long length)
+{
+       if (length <= 0)
+               return;
+
+       safe_udelay(length);
+}
+
+static void send_space_homebrew(long length)
+{
+       off();
+       if (length <= 0)
+               return;
+       safe_udelay(length);
+}
+
+static void rbwrite(int l)
+{
+       if (lirc_buffer_full(&rbuf)) {
+               /* no new signals will be accepted */
+               dprintk("Buffer overrun\n");
+               return;
+       }
+       lirc_buffer_write(&rbuf, (void *)&l);
+}
+
+static void frbwrite(int l)
+{
+       /* simple noise filter */
+       static int pulse, space;
+       static unsigned int ptr;
+
+       if (ptr > 0 && (l & PULSE_BIT)) {
+               pulse += l & PULSE_MASK;
+               if (pulse > 250) {
+                       rbwrite(space);
+                       rbwrite(pulse | PULSE_BIT);
+                       ptr = 0;
+                       pulse = 0;
+               }
+               return;
+       }
+       if (!(l & PULSE_BIT)) {
+               if (ptr == 0) {
+                       if (l > 20000) {
+                               space = l;
+                               ptr++;
+                               return;
+                       }
+               } else {
+                       if (l > 20000) {
+                               space += pulse;
+                               if (space > PULSE_MASK)
+                                       space = PULSE_MASK;
+                               space += l;
+                               if (space > PULSE_MASK)
+                                       space = PULSE_MASK;
+                               pulse = 0;
+                               return;
+                       }
+                       rbwrite(space);
+                       rbwrite(pulse | PULSE_BIT);
+                       ptr = 0;
+                       pulse = 0;
+               }
+       }
+       rbwrite(l);
+}
+
+static irqreturn_t irq_handler(int i, void *blah)
+{
+       struct timeval tv;
+       int counter, dcd;
+       u8 status;
+       long deltv;
+       int data;
+       static int last_dcd = -1;
+
+       if ((sinp(UART_IIR) & UART_IIR_NO_INT)) {
+               /* not our interrupt */
+               return IRQ_NONE;
+       }
+
+       counter = 0;
+       do {
+               counter++;
+               status = sinp(UART_MSR);
+               if (counter > RS_ISR_PASS_LIMIT) {
+                       printk(KERN_WARNING LIRC_DRIVER_NAME ": AIEEEE: "
+                              "We're caught!\n");
+                       break;
+               }
+               if ((status & hardware[type].signal_pin_change)
+                   && sense != -1) {
+                       /* get current time */
+                       do_gettimeofday(&tv);
+
+                       /* New mode, written by Trent Piepho
+                          <xyzzy@u.washington.edu>. */
+
+                       /*
+                        * The old format was not very portable.
+                        * We now use an int to pass pulses
+                        * and spaces to user space.
+                        *
+                        * If PULSE_BIT is set a pulse has been
+                        * received, otherwise a space has been
+                        * received.  The driver needs to know if your
+                        * receiver is active high or active low, or
+                        * the space/pulse sense could be
+                        * inverted. The bits denoted by PULSE_MASK are
+                        * the length in microseconds. Lengths greater
+                        * than or equal to 16 seconds are clamped to
+                        * PULSE_MASK.  All other bits are unused.
+                        * This is a much simpler interface for user
+                        * programs, as well as eliminating "out of
+                        * phase" errors with space/pulse
+                        * autodetection.
+                        */
+
+                       /* calc time since last interrupt in microseconds */
+                       dcd = (status & hardware[type].signal_pin) ? 1 : 0;
+
+                       if (dcd == last_dcd) {
+                               printk(KERN_WARNING LIRC_DRIVER_NAME
+                               ": ignoring spike: %d %d %lx %lx %lx %lx\n",
+                               dcd, sense,
+                               tv.tv_sec, lasttv.tv_sec,
+                               tv.tv_usec, lasttv.tv_usec);
+                               continue;
+                       }
+
+                       deltv = tv.tv_sec-lasttv.tv_sec;
+                       if (tv.tv_sec < lasttv.tv_sec ||
+                           (tv.tv_sec == lasttv.tv_sec &&
+                            tv.tv_usec < lasttv.tv_usec)) {
+                               printk(KERN_WARNING LIRC_DRIVER_NAME
+                                      ": AIEEEE: your clock just jumped "
+                                      "backwards\n");
+                               printk(KERN_WARNING LIRC_DRIVER_NAME
+                                      ": %d %d %lx %lx %lx %lx\n",
+                                      dcd, sense,
+                                      tv.tv_sec, lasttv.tv_sec,
+                                      tv.tv_usec, lasttv.tv_usec);
+                               data = PULSE_MASK;
+                       } else if (deltv > 15) {
+                               data = PULSE_MASK; /* really long time */
+                               if (!(dcd^sense)) {
+                                       /* sanity check */
+                                       printk(KERN_WARNING LIRC_DRIVER_NAME
+                                              ": AIEEEE: "
+                                              "%d %d %lx %lx %lx %lx\n",
+                                              dcd, sense,
+                                              tv.tv_sec, lasttv.tv_sec,
+                                              tv.tv_usec, lasttv.tv_usec);
+                                       /*
+                                        * detecting pulse while this
+                                        * MUST be a space!
+                                        */
+                                       sense = sense ? 0 : 1;
+                               }
+                       } else
+                               data = (int) (deltv*1000000 +
+                                              tv.tv_usec -
+                                              lasttv.tv_usec);
+                       frbwrite(dcd^sense ? data : (data|PULSE_BIT));
+                       lasttv = tv;
+                       last_dcd = dcd;
+                       wake_up_interruptible(&rbuf.wait_poll);
+               }
+       } while (!(sinp(UART_IIR) & UART_IIR_NO_INT)); /* still pending ? */
+       return IRQ_HANDLED;
+}
+
+
+static int hardware_init_port(void)
+{
+       u8 scratch, scratch2, scratch3;
+
+       /*
+        * This is a simple port existence test, borrowed from the autoconfig
+        * function in drivers/serial/8250.c
+        */
+       scratch = sinp(UART_IER);
+       soutp(UART_IER, 0);
+#ifdef __i386__
+       outb(0xff, 0x080);
+#endif
+       scratch2 = sinp(UART_IER) & 0x0f;
+       soutp(UART_IER, 0x0f);
+#ifdef __i386__
+       outb(0x00, 0x080);
+#endif
+       scratch3 = sinp(UART_IER) & 0x0f;
+       soutp(UART_IER, scratch);
+       if (scratch2 != 0 || scratch3 != 0x0f) {
+               /* we fail, there's nothing here */
+               printk(KERN_ERR LIRC_DRIVER_NAME ": port existence test "
+                      "failed, cannot continue\n");
+               return -EINVAL;
+       }
+
+
+
+       /* Set DLAB 0. */
+       soutp(UART_LCR, sinp(UART_LCR) & (~UART_LCR_DLAB));
+
+       /* First of all, disable all interrupts */
+       soutp(UART_IER, sinp(UART_IER) &
+             (~(UART_IER_MSI|UART_IER_RLSI|UART_IER_THRI|UART_IER_RDI)));
+
+       /* Clear registers. */
+       sinp(UART_LSR);
+       sinp(UART_RX);
+       sinp(UART_IIR);
+       sinp(UART_MSR);
+
+#ifdef CONFIG_LIRC_SERIAL_NSLU2
+       if (type == LIRC_NSLU2) {
+               /* Setup NSLU2 UART */
+
+               /* Enable UART */
+               soutp(UART_IER, sinp(UART_IER) | UART_IE_IXP42X_UUE);
+               /* Disable Receiver data Time out interrupt */
+               soutp(UART_IER, sinp(UART_IER) & ~UART_IE_IXP42X_RTOIE);
+               /* set out2 = interrupt unmask; off() doesn't set MCR
+                  on NSLU2 */
+               soutp(UART_MCR, UART_MCR_RTS|UART_MCR_OUT2);
+       }
+#endif
+
+       /* Set line for power source */
+       off();
+
+       /* Clear registers again to be sure. */
+       sinp(UART_LSR);
+       sinp(UART_RX);
+       sinp(UART_IIR);
+       sinp(UART_MSR);
+
+       switch (type) {
+       case LIRC_IRDEO:
+       case LIRC_IRDEO_REMOTE:
+               /* setup port to 7N1 @ 115200 Baud */
+               /* 7N1+start = 9 bits at 115200 ~ 3 bits at 38kHz */
+
+               /* Set DLAB 1. */
+               soutp(UART_LCR, sinp(UART_LCR) | UART_LCR_DLAB);
+               /* Set divisor to 1 => 115200 Baud */
+               soutp(UART_DLM, 0);
+               soutp(UART_DLL, 1);
+               /* Set DLAB 0 +  7N1 */
+               soutp(UART_LCR, UART_LCR_WLEN7);
+               /* THR interrupt already disabled at this point */
+               break;
+       default:
+               break;
+       }
+
+       return 0;
+}
+
+static int init_port(void)
+{
+       int i, nlow, nhigh;
+
+       /* Reserve io region. */
+       /*
+        * Future MMAP-Developers: Attention!
+        * For memory mapped I/O you *might* need to use ioremap() first,
+        * for the NSLU2 it's done in boot code.
+        */
+       if (((iommap != 0)
+            && (request_mem_region(iommap, 8 << ioshift,
+                                   LIRC_DRIVER_NAME) == NULL))
+          || ((iommap == 0)
+              && (request_region(io, 8, LIRC_DRIVER_NAME) == NULL))) {
+               printk(KERN_ERR  LIRC_DRIVER_NAME
+                      ": port %04x already in use\n", io);
+               printk(KERN_WARNING LIRC_DRIVER_NAME
+                      ": use 'setserial /dev/ttySX uart none'\n");
+               printk(KERN_WARNING LIRC_DRIVER_NAME
+                      ": or compile the serial port driver as module and\n");
+               printk(KERN_WARNING LIRC_DRIVER_NAME
+                      ": make sure this module is loaded first\n");
+               return -EBUSY;
+       }
+
+       if (hardware_init_port() < 0)
+               return -EINVAL;
+
+       /* Initialize pulse/space widths */
+       init_timing_params(duty_cycle, freq);
+
+       /* If pin is high, then this must be an active low receiver. */
+       if (sense == -1) {
+               /* wait 1/2 sec for the power supply */
+               msleep(500);
+
+               /*
+                * probe 9 times every 0.04s, collect "votes" for
+                * active high/low
+                */
+               nlow = 0;
+               nhigh = 0;
+               for (i = 0; i < 9; i++) {
+                       if (sinp(UART_MSR) & hardware[type].signal_pin)
+                               nlow++;
+                       else
+                               nhigh++;
+                       msleep(40);
+               }
+               sense = (nlow >= nhigh ? 1 : 0);
+               printk(KERN_INFO LIRC_DRIVER_NAME  ": auto-detected active "
+                      "%s receiver\n", sense ? "low" : "high");
+       } else
+               printk(KERN_INFO LIRC_DRIVER_NAME  ": Manually using active "
+                      "%s receiver\n", sense ? "low" : "high");
+
+       return 0;
+}
+
+static int set_use_inc(void *data)
+{
+       int result;
+       unsigned long flags;
+
+       /* initialize timestamp */
+       do_gettimeofday(&lasttv);
+
+       result = request_irq(irq, irq_handler,
+                            IRQF_DISABLED | (share_irq ? IRQF_SHARED : 0),
+                            LIRC_DRIVER_NAME, (void *)&hardware);
+
+       switch (result) {
+       case -EBUSY:
+               printk(KERN_ERR LIRC_DRIVER_NAME ": IRQ %d busy\n", irq);
+               return -EBUSY;
+       case -EINVAL:
+               printk(KERN_ERR LIRC_DRIVER_NAME
+                      ": Bad irq number or handler\n");
+               return -EINVAL;
+       default:
+               dprintk("Interrupt %d, port %04x obtained\n", irq, io);
+               break;
+       };
+
+       spin_lock_irqsave(&hardware[type].lock, flags);
+
+       /* Set DLAB 0. */
+       soutp(UART_LCR, sinp(UART_LCR) & (~UART_LCR_DLAB));
+
+       soutp(UART_IER, sinp(UART_IER)|UART_IER_MSI);
+
+       spin_unlock_irqrestore(&hardware[type].lock, flags);
+
+       return 0;
+}
+
+static void set_use_dec(void *data)
+{      unsigned long flags;
+
+       spin_lock_irqsave(&hardware[type].lock, flags);
+
+       /* Set DLAB 0. */
+       soutp(UART_LCR, sinp(UART_LCR) & (~UART_LCR_DLAB));
+
+       /* First of all, disable all interrupts */
+       soutp(UART_IER, sinp(UART_IER) &
+             (~(UART_IER_MSI|UART_IER_RLSI|UART_IER_THRI|UART_IER_RDI)));
+       spin_unlock_irqrestore(&hardware[type].lock, flags);
+
+       free_irq(irq, (void *)&hardware);
+
+       dprintk("freed IRQ %d\n", irq);
+}
+
+static ssize_t lirc_write(struct file *file, const char *buf,
+                        size_t n, loff_t *ppos)
+{
+       int i, count;
+       unsigned long flags;
+       long delta = 0;
+       int *wbuf;
+
+       if (!(hardware[type].features & LIRC_CAN_SEND_PULSE))
+               return -EBADF;
+
+       count = n / sizeof(int);
+       if (n % sizeof(int) || count % 2 == 0)
+               return -EINVAL;
+       wbuf = memdup_user(buf, n);
+       if (PTR_ERR(wbuf))
+               return PTR_ERR(wbuf);
+       spin_lock_irqsave(&hardware[type].lock, flags);
+       if (type == LIRC_IRDEO) {
+               /* DTR, RTS down */
+               on();
+       }
+       for (i = 0; i < count; i++) {
+               if (i%2)
+                       hardware[type].send_space(wbuf[i] - delta);
+               else
+                       delta = hardware[type].send_pulse(wbuf[i]);
+       }
+       off();
+       spin_unlock_irqrestore(&hardware[type].lock, flags);
+       return n;
+}
+
+static long lirc_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
+{
+       int result;
+       unsigned long value;
+       unsigned int ivalue;
+
+       switch (cmd) {
+       case LIRC_GET_SEND_MODE:
+               if (!(hardware[type].features&LIRC_CAN_SEND_MASK))
+                       return -ENOIOCTLCMD;
+
+               result = put_user(LIRC_SEND2MODE
+                                 (hardware[type].features&LIRC_CAN_SEND_MASK),
+                                 (unsigned long *) arg);
+               if (result)
+                       return result;
+               break;
+
+       case LIRC_SET_SEND_MODE:
+               if (!(hardware[type].features&LIRC_CAN_SEND_MASK))
+                       return -ENOIOCTLCMD;
+
+               result = get_user(value, (unsigned long *) arg);
+               if (result)
+                       return result;
+               /* only LIRC_MODE_PULSE supported */
+               if (value != LIRC_MODE_PULSE)
+                       return -ENOSYS;
+               break;
+
+       case LIRC_GET_LENGTH:
+               return -ENOSYS;
+               break;
+
+       case LIRC_SET_SEND_DUTY_CYCLE:
+               dprintk("SET_SEND_DUTY_CYCLE\n");
+               if (!(hardware[type].features&LIRC_CAN_SET_SEND_DUTY_CYCLE))
+                       return -ENOIOCTLCMD;
+
+               result = get_user(ivalue, (unsigned int *) arg);
+               if (result)
+                       return result;
+               if (ivalue <= 0 || ivalue > 100)
+                       return -EINVAL;
+               return init_timing_params(ivalue, freq);
+               break;
+
+       case LIRC_SET_SEND_CARRIER:
+               dprintk("SET_SEND_CARRIER\n");
+               if (!(hardware[type].features&LIRC_CAN_SET_SEND_CARRIER))
+                       return -ENOIOCTLCMD;
+
+               result = get_user(ivalue, (unsigned int *) arg);
+               if (result)
+                       return result;
+               if (ivalue > 500000 || ivalue < 20000)
+                       return -EINVAL;
+               return init_timing_params(duty_cycle, ivalue);
+               break;
+
+       default:
+               return lirc_dev_fop_ioctl(filep, cmd, arg);
+       }
+       return 0;
+}
+
+static struct file_operations lirc_fops = {
+       .owner          = THIS_MODULE,
+       .write          = lirc_write,
+       .unlocked_ioctl = lirc_ioctl,
+       .read           = lirc_dev_fop_read,
+       .poll           = lirc_dev_fop_poll,
+       .open           = lirc_dev_fop_open,
+       .release        = lirc_dev_fop_close,
+};
+
+static struct lirc_driver driver = {
+       .name           = LIRC_DRIVER_NAME,
+       .minor          = -1,
+       .code_length    = 1,
+       .sample_rate    = 0,
+       .data           = NULL,
+       .add_to_buf     = NULL,
+       .rbuf           = &rbuf,
+       .set_use_inc    = set_use_inc,
+       .set_use_dec    = set_use_dec,
+       .fops           = &lirc_fops,
+       .dev            = NULL,
+       .owner          = THIS_MODULE,
+};
+
+static struct platform_device *lirc_serial_dev;
+
+static int __devinit lirc_serial_probe(struct platform_device *dev)
+{
+       return 0;
+}
+
+static int __devexit lirc_serial_remove(struct platform_device *dev)
+{
+       return 0;
+}
+
+static int lirc_serial_suspend(struct platform_device *dev,
+                              pm_message_t state)
+{
+       /* Set DLAB 0. */
+       soutp(UART_LCR, sinp(UART_LCR) & (~UART_LCR_DLAB));
+
+       /* Disable all interrupts */
+       soutp(UART_IER, sinp(UART_IER) &
+             (~(UART_IER_MSI|UART_IER_RLSI|UART_IER_THRI|UART_IER_RDI)));
+
+       /* Clear registers. */
+       sinp(UART_LSR);
+       sinp(UART_RX);
+       sinp(UART_IIR);
+       sinp(UART_MSR);
+
+       return 0;
+}
+
+/* twisty maze... need a forward-declaration here... */
+static void lirc_serial_exit(void);
+
+static int lirc_serial_resume(struct platform_device *dev)
+{
+       unsigned long flags;
+
+       if (hardware_init_port() < 0) {
+               lirc_serial_exit();
+               return -EINVAL;
+       }
+
+       spin_lock_irqsave(&hardware[type].lock, flags);
+       /* Enable Interrupt */
+       do_gettimeofday(&lasttv);
+       soutp(UART_IER, sinp(UART_IER)|UART_IER_MSI);
+       off();
+
+       lirc_buffer_clear(&rbuf);
+
+       spin_unlock_irqrestore(&hardware[type].lock, flags);
+
+       return 0;
+}
+
+static struct platform_driver lirc_serial_driver = {
+       .probe          = lirc_serial_probe,
+       .remove         = __devexit_p(lirc_serial_remove),
+       .suspend        = lirc_serial_suspend,
+       .resume         = lirc_serial_resume,
+       .driver         = {
+               .name   = "lirc_serial",
+               .owner  = THIS_MODULE,
+       },
+};
+
+static int __init lirc_serial_init(void)
+{
+       int result;
+
+       /* Init read buffer. */
+       result = lirc_buffer_init(&rbuf, sizeof(int), RBUF_LEN);
+       if (result < 0)
+               return -ENOMEM;
+
+       result = platform_driver_register(&lirc_serial_driver);
+       if (result) {
+               printk("lirc register returned %d\n", result);
+               goto exit_buffer_free;
+       }
+
+       lirc_serial_dev = platform_device_alloc("lirc_serial", 0);
+       if (!lirc_serial_dev) {
+               result = -ENOMEM;
+               goto exit_driver_unregister;
+       }
+
+       result = platform_device_add(lirc_serial_dev);
+       if (result)
+               goto exit_device_put;
+
+       return 0;
+
+exit_device_put:
+       platform_device_put(lirc_serial_dev);
+exit_driver_unregister:
+       platform_driver_unregister(&lirc_serial_driver);
+exit_buffer_free:
+       lirc_buffer_free(&rbuf);
+       return result;
+}
+
+static void lirc_serial_exit(void)
+{
+       platform_device_unregister(lirc_serial_dev);
+       platform_driver_unregister(&lirc_serial_driver);
+       lirc_buffer_free(&rbuf);
+}
+
+static int __init lirc_serial_init_module(void)
+{
+       int result;
+
+       result = lirc_serial_init();
+       if (result)
+               return result;
+
+       switch (type) {
+       case LIRC_HOMEBREW:
+       case LIRC_IRDEO:
+       case LIRC_IRDEO_REMOTE:
+       case LIRC_ANIMAX:
+       case LIRC_IGOR:
+               /* if nothing specified, use ttyS0/com1 and irq 4 */
+               io = io ? io : 0x3f8;
+               irq = irq ? irq : 4;
+               break;
+#ifdef CONFIG_LIRC_SERIAL_NSLU2
+       case LIRC_NSLU2:
+               io = io ? io : IRQ_IXP4XX_UART2;
+               irq = irq ? irq : (IXP4XX_UART2_BASE_VIRT + REG_OFFSET);
+               iommap = iommap ? iommap : IXP4XX_UART2_BASE_PHYS;
+               ioshift = ioshift ? ioshift : 2;
+               break;
+#endif
+       default:
+               result = -EINVAL;
+               goto exit_serial_exit;
+       }
+       if (!softcarrier) {
+               switch (type) {
+               case LIRC_HOMEBREW:
+               case LIRC_IGOR:
+#ifdef CONFIG_LIRC_SERIAL_NSLU2
+               case LIRC_NSLU2:
+#endif
+                       hardware[type].features &=
+                               ~(LIRC_CAN_SET_SEND_DUTY_CYCLE|
+                                 LIRC_CAN_SET_SEND_CARRIER);
+                       break;
+               }
+       }
+
+       result = init_port();
+       if (result < 0)
+               goto exit_serial_exit;
+       driver.features = hardware[type].features;
+       driver.dev = &lirc_serial_dev->dev;
+       driver.minor = lirc_register_driver(&driver);
+       if (driver.minor < 0) {
+               printk(KERN_ERR  LIRC_DRIVER_NAME
+                      ": register_chrdev failed!\n");
+               result = -EIO;
+               goto exit_release;
+       }
+       return 0;
+exit_release:
+       release_region(io, 8);
+exit_serial_exit:
+       lirc_serial_exit();
+       return result;
+}
+
+static void __exit lirc_serial_exit_module(void)
+{
+       lirc_serial_exit();
+       if (iommap != 0)
+               release_mem_region(iommap, 8 << ioshift);
+       else
+               release_region(io, 8);
+       lirc_unregister_driver(driver.minor);
+       dprintk("cleaned up module\n");
+}
+
+
+module_init(lirc_serial_init_module);
+module_exit(lirc_serial_exit_module);
+
+MODULE_DESCRIPTION("Infra-red receiver driver for serial ports.");
+MODULE_AUTHOR("Ralph Metzler, Trent Piepho, Ben Pfaff, "
+             "Christoph Bartelmus, Andrei Tanas");
+MODULE_LICENSE("GPL");
+
+module_param(type, int, S_IRUGO);
+MODULE_PARM_DESC(type, "Hardware type (0 = home-brew, 1 = IRdeo,"
+                " 2 = IRdeo Remote, 3 = AnimaX, 4 = IgorPlug,"
+                " 5 = NSLU2 RX:CTS2/TX:GreenLED)");
+
+module_param(io, int, S_IRUGO);
+MODULE_PARM_DESC(io, "I/O address base (0x3f8 or 0x2f8)");
+
+/* some architectures (e.g. intel xscale) have memory mapped registers */
+module_param(iommap, bool, S_IRUGO);
+MODULE_PARM_DESC(iommap, "physical base for memory mapped I/O"
+               " (0 = no memory mapped io)");
+
+/*
+ * some architectures (e.g. intel xscale) align the 8bit serial registers
+ * on 32bit word boundaries.
+ * See linux-kernel/serial/8250.c serial_in()/out()
+ */
+module_param(ioshift, int, S_IRUGO);
+MODULE_PARM_DESC(ioshift, "shift I/O register offset (0 = no shift)");
+
+module_param(irq, int, S_IRUGO);
+MODULE_PARM_DESC(irq, "Interrupt (4 or 3)");
+
+module_param(share_irq, bool, S_IRUGO);
+MODULE_PARM_DESC(share_irq, "Share interrupts (0 = off, 1 = on)");
+
+module_param(sense, bool, S_IRUGO);
+MODULE_PARM_DESC(sense, "Override autodetection of IR receiver circuit"
+                " (0 = active high, 1 = active low )");
+
+#ifdef CONFIG_LIRC_SERIAL_TRANSMITTER
+module_param(txsense, bool, S_IRUGO);
+MODULE_PARM_DESC(txsense, "Sense of transmitter circuit"
+                " (0 = active high, 1 = active low )");
+#endif
+
+module_param(softcarrier, bool, S_IRUGO);
+MODULE_PARM_DESC(softcarrier, "Software carrier (0 = off, 1 = on, default on)");
+
+module_param(debug, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "Enable debugging messages");