text: /*
   * 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
   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #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/ktime.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 <linux/gpio.h>
  #include <linux/io.h>
  #include <linux/irq.h>
  #include <linux/fcntl.h>
  #include <linux/spinlock.h>
  
  /* 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 bool iommap;
  static int ioshift;
  static bool softcarrier = true;
  static bool share_irq;
  static int sense = -1;	/* -1 = auto, 0 = active high, 1 = active low */
  static bool txsense;	/* 0 = active high, 1 = active low */
  
  /* 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] = {
  		.lock = __SPIN_LOCK_UNLOCKED(hardware[LIRC_HOMEBREW].lock),
  		.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] = {
  		.lock = __SPIN_LOCK_UNLOCKED(hardware[LIRC_IRDEO].lock),
  		.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] = {
  		.lock = __SPIN_LOCK_UNLOCKED(hardware[LIRC_IRDEO_REMOTE].lock),
  		.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] = {
  		.lock = __SPIN_LOCK_UNLOCKED(hardware[LIRC_ANIMAX].lock),
  		.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] = {
  		.lock = __SPIN_LOCK_UNLOCKED(hardware[LIRC_IGOR].lock),
  		.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
  	},
  };
  
  #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 ktime_t lastkt;
  
  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)
  		/* 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)
  		/* the register is memory-mapped */
  		offset <<= ioshift;
  
  	outb(value, io + offset);
  }
  
  static void on(void)
  {
  	if (txsense)
  		soutp(UART_MCR, hardware[type].off);
  	else
  		soutp(UART_MCR, hardware[type].on);
  }
  
  static void off(void)
  {
  	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
   */
  
  static int init_timing_params(unsigned int new_duty_cycle,
  		unsigned int new_freq)
  {
  	__u64 loops_per_sec, work;
  
  	duty_cycle = new_duty_cycle;
  	freq = new_freq;
  
  	loops_per_sec = __this_cpu_read(cpu.info.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 */
  
  	/*
  	 * 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;
  	pr_debug("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, __this_cpu_read(cpu_info.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;
  	pr_debug("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;
  }
  
  /* 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
   *
   * This should use ndelay instead.
   */
  
  /* 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;
  }
  
  static long send_pulse_homebrew(unsigned long length)
  {
  	if (length <= 0)
  		return 0;
  
  	if (softcarrier)
  		return send_pulse_homebrew_softcarrier(length);
  
  	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 */
  		pr_debug("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 lirc_irq_handler(int i, void *blah)
  {
  	ktime_t kt;
  	int counter, dcd;
  	u8 status;
  	ktime_t delkt;
  	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) {
  			pr_warn("AIEEEE: We're caught!\n");
  			break;
  		}
  		if ((status & hardware[type].signal_pin_change)
  		    && sense != -1) {
  			/* get current time */
  			kt = ktime_get();
  
  			/* 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) {
  				pr_warn("ignoring spike: %d %d %llx %llx\n",
  					dcd, sense, ktime_to_us(kt),
  					ktime_to_us(lastkt));
  				continue;
  			}
  
  			delkt = ktime_sub(kt, lastkt);
  			if (ktime_compare(delkt, ktime_set(15, 0)) > 0) {
  				data = PULSE_MASK; /* really long time */
  				if (!(dcd^sense)) {
  					/* sanity check */
  					pr_warn("AIEEEE: %d %d %llx %llx\n",
  						dcd, sense, ktime_to_us(kt),
  						ktime_to_us(lastkt));
  					/*
  					 * detecting pulse while this
  					 * MUST be a space!
  					 */
  					sense = sense ? 0 : 1;
  				}
  			} else
  				data = (int) ktime_to_us(delkt);
  			frbwrite(dcd^sense ? data : (data|PULSE_BIT));
  			lastkt = kt;
  			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 */
  		pr_err("port existence test failed, cannot continue\n");
  		return -ENODEV;
  	}
  
  
  
  	/* 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);
  
  	/* 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 lirc_serial_probe(struct platform_device *dev)
  {
  	int i, nlow, nhigh, result;
  
  	result = devm_request_irq(&dev->dev, irq, lirc_irq_handler,
  			     (share_irq ? IRQF_SHARED : 0),
  			     LIRC_DRIVER_NAME, &hardware);
  	if (result < 0) {
  		if (result == -EBUSY)
  			dev_err(&dev->dev, "IRQ %d busy\n", irq);
  		else if (result == -EINVAL)
  			dev_err(&dev->dev, "Bad irq number or handler\n");
  		return result;
  	}
  
  	/* 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)
  	     && (devm_request_mem_region(&dev->dev, iommap, 8 << ioshift,
  					 LIRC_DRIVER_NAME) == NULL))
  	   || ((!iommap)
  	       && (devm_request_region(&dev->dev, io, 8,
  				       LIRC_DRIVER_NAME) == NULL))) {
  		dev_err(&dev->dev, "port %04x already in use\n", io);
  		dev_warn(&dev->dev, "use 'setserial /dev/ttySX uart none'\n");
  		dev_warn(&dev->dev,
  			 "or compile the serial port driver as module and\n");
  		dev_warn(&dev->dev, "make sure this module is loaded first\n");
  		return -EBUSY;
  	}
  
  	result = hardware_init_port();
  	if (result < 0)
  		return result;
  
  	/* 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;
  		dev_info(&dev->dev, "auto-detected active %s receiver\n",
  			 sense ? "low" : "high");
  	} else
  		dev_info(&dev->dev, "Manually using active %s receiver\n",
  			 sense ? "low" : "high");
  
  	dev_dbg(&dev->dev, "Interrupt %d, port %04x obtained\n", irq, io);
  	return 0;
  }
  
  static int set_use_inc(void *data)
  {
  	unsigned long flags;
  
  	/* initialize timestamp */
  	lastkt = ktime_get();
  
  	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);
  }
  
  static ssize_t lirc_write(struct file *file, const char __user *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 -EPERM;
  
  	count = n / sizeof(int);
  	if (n % sizeof(int) || count % 2 == 0)
  		return -EINVAL;
  	wbuf = memdup_user(buf, n);
  	if (IS_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);
  	kfree(wbuf);
  	return n;
  }
  
  static long lirc_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
  {
  	int result;
  	u32 __user *uptr = (u32 __user *)arg;
  	u32 value;
  
  	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),
  				  uptr);
  		if (result)
  			return result;
  		break;
  
  	case LIRC_SET_SEND_MODE:
  		if (!(hardware[type].features&LIRC_CAN_SEND_MASK))
  			return -ENOIOCTLCMD;
  
  		result = get_user(value, uptr);
  		if (result)
  			return result;
  		/* only LIRC_MODE_PULSE supported */
  		if (value != LIRC_MODE_PULSE)
  			return -EINVAL;
  		break;
  
  	case LIRC_GET_LENGTH:
  		return -ENOIOCTLCMD;
  
  	case LIRC_SET_SEND_DUTY_CYCLE:
  		pr_debug("SET_SEND_DUTY_CYCLE\n");
  		if (!(hardware[type].features&LIRC_CAN_SET_SEND_DUTY_CYCLE))
  			return -ENOIOCTLCMD;
  
  		result = get_user(value, uptr);
  		if (result)
  			return result;
  		if (value <= 0 || value > 100)
  			return -EINVAL;
  		return init_timing_params(value, freq);
  
  	case LIRC_SET_SEND_CARRIER:
  		pr_debug("SET_SEND_CARRIER\n");
  		if (!(hardware[type].features&LIRC_CAN_SET_SEND_CARRIER))
  			return -ENOIOCTLCMD;
  
  		result = get_user(value, uptr);
  		if (result)
  			return result;
  		if (value > 500000 || value < 20000)
  			return -EINVAL;
  		return init_timing_params(duty_cycle, value);
  
  	default:
  		return lirc_dev_fop_ioctl(filep, cmd, arg);
  	}
  	return 0;
  }
  
  static const struct file_operations lirc_fops = {
  	.owner		= THIS_MODULE,
  	.write		= lirc_write,
  	.unlocked_ioctl	= lirc_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl	= lirc_ioctl,
  #endif
  	.read		= lirc_dev_fop_read,
  	.poll		= lirc_dev_fop_poll,
  	.open		= lirc_dev_fop_open,
  	.release	= lirc_dev_fop_close,
  	.llseek		= no_llseek,
  };
  
  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 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;
  	int result;
  
  	result = hardware_init_port();
  	if (result < 0)
  		return result;
  
  	spin_lock_irqsave(&hardware[type].lock, flags);
  	/* Enable Interrupt */
  	lastkt = ktime_get();
  	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,
  	.suspend	= lirc_serial_suspend,
  	.resume		= lirc_serial_resume,
  	.driver		= {
  		.name	= "lirc_serial",
  	},
  };
  
  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 result;
  
  	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;
  
  	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;
  	default:
  		return -EINVAL;
  	}
  	if (!softcarrier) {
  		switch (type) {
  		case LIRC_HOMEBREW:
  		case LIRC_IGOR:
  			hardware[type].features &=
  				~(LIRC_CAN_SET_SEND_DUTY_CYCLE|
  				  LIRC_CAN_SET_SEND_CARRIER);
  			break;
  		}
  	}
  
  	/* make sure sense is either -1, 0, or 1 */
  	if (sense != -1)
  		sense = !!sense;
  
  	result = lirc_serial_init();
  	if (result)
  		return result;
  
  	driver.features = hardware[type].features;
  	driver.dev = &lirc_serial_dev->dev;
  	driver.minor = lirc_register_driver(&driver);
  	if (driver.minor < 0) {
  		pr_err("register_chrdev failed!\n");
  		lirc_serial_exit();
  		return driver.minor;
  	}
  	return 0;
  }
  
  static void __exit lirc_serial_exit_module(void)
  {
  	lirc_unregister_driver(driver.minor);
  	lirc_serial_exit();
  	pr_debug("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/drivers/tty/serial/8250/8250.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, int, 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)");
  