[media] winbond-cir: add carrier detection

The winbond hardware has a counter for leading edges, which increases as
they are received. As we read raw IR from a fifo in an interrupt handler,
we cannot correlate them to specific IR pulses so we simply count all
pulses and edges until we go idle and disable the receiver.
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/rc/winbond-cir.c

@@ -7,6 +7,7 @@
  *  with minor modifications.
  *
  *  Original Author: David Härdeman <david@hardeman.nu>
+ *     Copyright (C) 2012 Sean Young <sean@mess.org>
  *     Copyright (C) 2009 - 2011 David Härdeman <david@hardeman.nu>
  *
  *  Dedicated to my daughter Matilda, without whose loving attention this
@@ -22,9 +23,7 @@
  *    o IR Receive
  *    o IR Transmit
  *    o Wake-On-CIR functionality
- *
- *  To do:
- *    o Learning
+ *    o Carrier detection
  *
  *  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
@@ -149,6 +148,12 @@
 #define WBCIR_REGSEL_MASK	0x20
 /* Starting address of selected register in WBCIR_REG_WCEIR_INDEX */
 #define WBCIR_REG_ADDR0		0x00
+/* Enable carrier counter */
+#define WBCIR_CNTR_EN		0x01
+/* Reset carrier counter */
+#define WBCIR_CNTR_R		0x02
+/* Invert TX */
+#define WBCIR_IRTX_INV		0x04
 
 /* Valid banks for the SP3 UART */
 enum wbcir_bank {
@@ -207,6 +212,8 @@ struct wbcir_data {
 	/* RX state */
 	enum wbcir_rxstate rxstate;
 	struct led_trigger *rxtrigger;
+	int carrier_report_enabled;
+	u32 pulse_duration;
 
 	/* TX state */
 	enum wbcir_txstate txstate;
@@ -328,6 +335,30 @@ wbcir_to_rc6cells(u8 val)
  *
  *****************************************************************************/
 
+static void
+wbcir_carrier_report(struct wbcir_data *data)
+{
+	unsigned counter = inb(data->ebase + WBCIR_REG_ECEIR_CNT_LO) |
+			inb(data->ebase + WBCIR_REG_ECEIR_CNT_HI) << 8;
+
+	if (counter > 0 && counter < 0xffff) {
+		DEFINE_IR_RAW_EVENT(ev);
+
+		ev.carrier_report = 1;
+		ev.carrier = DIV_ROUND_CLOSEST(counter * 1000000u,
+						data->pulse_duration);
+
+		ir_raw_event_store(data->dev, &ev);
+	}
+
+	/* reset and restart the counter */
+	data->pulse_duration = 0;
+	wbcir_set_bits(data->ebase + WBCIR_REG_ECEIR_CCTL, WBCIR_CNTR_R,
+						WBCIR_CNTR_EN | WBCIR_CNTR_R);
+	wbcir_set_bits(data->ebase + WBCIR_REG_ECEIR_CCTL, WBCIR_CNTR_EN,
+						WBCIR_CNTR_EN | WBCIR_CNTR_R);
+}
+
 static void
 wbcir_idle_rx(struct rc_dev *dev, bool idle)
 {
@@ -341,6 +372,10 @@ wbcir_idle_rx(struct rc_dev *dev, bool idle)
 	if (idle && data->rxstate != WBCIR_RXSTATE_INACTIVE) {
 		data->rxstate = WBCIR_RXSTATE_INACTIVE;
 		led_trigger_event(data->rxtrigger, LED_OFF);
+
+		if (data->carrier_report_enabled)
+			wbcir_carrier_report(data);
+
 		/* Tell hardware to go idle by setting RXINACTIVE */
 		outb(WBCIR_RX_DISABLE, data->sbase + WBCIR_REG_SP3_ASCR);
 	}
@@ -351,14 +386,21 @@ wbcir_irq_rx(struct wbcir_data *data, struct pnp_dev *device)
 {
 	u8 irdata;
 	DEFINE_IR_RAW_EVENT(rawir);
+	unsigned duration;
 
 	/* Since RXHDLEV is set, at least 8 bytes are in the FIFO */
 	while (inb(data->sbase + WBCIR_REG_SP3_LSR) & WBCIR_RX_AVAIL) {
 		irdata = inb(data->sbase + WBCIR_REG_SP3_RXDATA);
 		if (data->rxstate == WBCIR_RXSTATE_ERROR)
 			continue;
+
+		duration = ((irdata & 0x7F) + 1) * 2;
 		rawir.pulse = irdata & 0x80 ? false : true;
-		rawir.duration = US_TO_NS(((irdata & 0x7F) + 1) * 2);
+		rawir.duration = US_TO_NS(duration);
+
+		if (rawir.pulse)
+			data->pulse_duration += duration;
+
 		ir_raw_event_store_with_filter(data->dev, &rawir);
 	}
 
@@ -487,6 +529,33 @@ wbcir_irq_handler(int irqno, void *cookie)
  *
  *****************************************************************************/
 
+static int
+wbcir_set_carrier_report(struct rc_dev *dev, int enable)
+{
+	struct wbcir_data *data = dev->priv;
+	unsigned long flags;
+
+	spin_lock_irqsave(&data->spinlock, flags);
+
+	if (data->carrier_report_enabled == enable) {
+		spin_unlock_irqrestore(&data->spinlock, flags);
+		return 0;
+	}
+
+	data->pulse_duration = 0;
+	wbcir_set_bits(data->ebase + WBCIR_REG_ECEIR_CCTL, WBCIR_CNTR_R,
+						WBCIR_CNTR_EN | WBCIR_CNTR_R);
+
+	if (enable && data->dev->idle)
+		wbcir_set_bits(data->ebase + WBCIR_REG_ECEIR_CCTL,
+				WBCIR_CNTR_EN, WBCIR_CNTR_EN | WBCIR_CNTR_R);
+
+	data->carrier_report_enabled = enable;
+	spin_unlock_irqrestore(&data->spinlock, flags);
+
+	return 0;
+}
+
 static int
 wbcir_txcarrier(struct rc_dev *dev, u32 carrier)
 {
@@ -833,7 +902,7 @@ wbcir_init_hw(struct wbcir_data *data)
 
 	/* Set IRTX_INV */
 	if (invert)
-		outb(0x04, data->ebase + WBCIR_REG_ECEIR_CCTL);
+		outb(WBCIR_IRTX_INV, data->ebase + WBCIR_REG_ECEIR_CCTL);
 	else
 		outb(0x00, data->ebase + WBCIR_REG_ECEIR_CCTL);
 
@@ -1014,6 +1083,7 @@ wbcir_probe(struct pnp_dev *device, const struct pnp_device_id *dev_id)
 	data->dev->input_id.version = WBCIR_ID_CHIP;
 	data->dev->map_name = RC_MAP_RC6_MCE;
 	data->dev->s_idle = wbcir_idle_rx;
+	data->dev->s_carrier_report = wbcir_set_carrier_report;
 	data->dev->s_tx_mask = wbcir_txmask;
 	data->dev->s_tx_carrier = wbcir_txcarrier;
 	data->dev->tx_ir = wbcir_tx;