[media] rc: img-ir: add raw driver

Add raw IR remote control input driver for the ImgTec Infrared decoder
block's raw edge interrupts. Generic software protocol decoders are used
to allow multiple protocols to be supported at a time, including those
not supported by the hardware decoder.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/rc/img-ir/img-ir-raw.c

+/*
+ * ImgTec IR Raw Decoder found in PowerDown Controller.
+ *
+ * Copyright 2010-2014 Imagination Technologies Ltd.
+ *
+ * This ties into the input subsystem using the RC-core in raw mode. Raw IR
+ * signal edges are reported and decoded by generic software decoders.
+ */
+
+#include <linux/spinlock.h>
+#include <media/rc-core.h>
+#include "img-ir.h"
+
+#define ECHO_TIMEOUT_MS 150	/* ms between echos */
+
+/* must be called with priv->lock held */
+static void img_ir_refresh_raw(struct img_ir_priv *priv, u32 irq_status)
+{
+	struct img_ir_priv_raw *raw = &priv->raw;
+	struct rc_dev *rc_dev = priv->raw.rdev;
+	int multiple;
+	u32 ir_status;
+
+	/* find whether both rise and fall was detected */
+	multiple = ((irq_status & IMG_IR_IRQ_EDGE) == IMG_IR_IRQ_EDGE);
+	/*
+	 * If so, we need to see if the level has actually changed.
+	 * If it's just noise that we didn't have time to process,
+	 * there's no point reporting it.
+	 */
+	ir_status = img_ir_read(priv, IMG_IR_STATUS) & IMG_IR_IRRXD;
+	if (multiple && ir_status == raw->last_status)
+		return;
+	raw->last_status = ir_status;
+
+	/* report the edge to the IR raw decoders */
+	if (ir_status) /* low */
+		ir_raw_event_store_edge(rc_dev, IR_SPACE);
+	else /* high */
+		ir_raw_event_store_edge(rc_dev, IR_PULSE);
+	ir_raw_event_handle(rc_dev);
+}
+
+/* called with priv->lock held */
+void img_ir_isr_raw(struct img_ir_priv *priv, u32 irq_status)
+{
+	struct img_ir_priv_raw *raw = &priv->raw;
+
+	/* check not removing */
+	if (!raw->rdev)
+		return;
+
+	img_ir_refresh_raw(priv, irq_status);
+
+	/* start / push back the echo timer */
+	mod_timer(&raw->timer, jiffies + msecs_to_jiffies(ECHO_TIMEOUT_MS));
+}
+
+/*
+ * Echo timer callback function.
+ * The raw decoders expect to get a final sample even if there are no edges, in
+ * order to be assured of the final space. If there are no edges for a certain
+ * time we use this timer to emit a final sample to satisfy them.
+ */
+static void img_ir_echo_timer(unsigned long arg)
+{
+	struct img_ir_priv *priv = (struct img_ir_priv *)arg;
+
+	spin_lock_irq(&priv->lock);
+
+	/* check not removing */
+	if (priv->raw.rdev)
+		/*
+		 * It's safe to pass irq_status=0 since it's only used to check
+		 * for double edges.
+		 */
+		img_ir_refresh_raw(priv, 0);
+
+	spin_unlock_irq(&priv->lock);
+}
+
+void img_ir_setup_raw(struct img_ir_priv *priv)
+{
+	u32 irq_en;
+
+	if (!priv->raw.rdev)
+		return;
+
+	/* clear and enable edge interrupts */
+	spin_lock_irq(&priv->lock);
+	irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
+	irq_en |= IMG_IR_IRQ_EDGE;
+	img_ir_write(priv, IMG_IR_IRQ_CLEAR, IMG_IR_IRQ_EDGE);
+	img_ir_write(priv, IMG_IR_IRQ_ENABLE, irq_en);
+	spin_unlock_irq(&priv->lock);
+}
+
+int img_ir_probe_raw(struct img_ir_priv *priv)
+{
+	struct img_ir_priv_raw *raw = &priv->raw;
+	struct rc_dev *rdev;
+	int error;
+
+	/* Set up the echo timer */
+	setup_timer(&raw->timer, img_ir_echo_timer, (unsigned long)priv);
+
+	/* Allocate raw decoder */
+	raw->rdev = rdev = rc_allocate_device();
+	if (!rdev) {
+		dev_err(priv->dev, "cannot allocate raw input device\n");
+		return -ENOMEM;
+	}
+	rdev->priv = priv;
+	rdev->map_name = RC_MAP_EMPTY;
+	rdev->input_name = "IMG Infrared Decoder Raw";
+	rdev->driver_type = RC_DRIVER_IR_RAW;
+
+	/* Register raw decoder */
+	error = rc_register_device(rdev);
+	if (error) {
+		dev_err(priv->dev, "failed to register raw IR input device\n");
+		rc_free_device(rdev);
+		raw->rdev = NULL;
+		return error;
+	}
+
+	return 0;
+}
+
+void img_ir_remove_raw(struct img_ir_priv *priv)
+{
+	struct img_ir_priv_raw *raw = &priv->raw;
+	struct rc_dev *rdev = raw->rdev;
+	u32 irq_en;
+
+	if (!rdev)
+		return;
+
+	/* switch off and disable raw (edge) interrupts */
+	spin_lock_irq(&priv->lock);
+	raw->rdev = NULL;
+	irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
+	irq_en &= ~IMG_IR_IRQ_EDGE;
+	img_ir_write(priv, IMG_IR_IRQ_ENABLE, irq_en);
+	img_ir_write(priv, IMG_IR_IRQ_CLEAR, IMG_IR_IRQ_EDGE);
+	spin_unlock_irq(&priv->lock);
+
+	rc_unregister_device(rdev);
+
+	del_timer_sync(&raw->timer);
+}

drivers/media/rc/img-ir/img-ir-raw.h

+/*
+ * ImgTec IR Raw Decoder found in PowerDown Controller.
+ *
+ * Copyright 2010-2014 Imagination Technologies Ltd.
+ */
+
+#ifndef _IMG_IR_RAW_H_
+#define _IMG_IR_RAW_H_
+
+struct img_ir_priv;
+
+#ifdef CONFIG_IR_IMG_RAW
+
+/**
+ * struct img_ir_priv_raw - Private driver data for raw decoder.
+ * @rdev:		Raw remote control device
+ * @timer:		Timer to echo samples to keep soft decoders happy.
+ * @last_status:	Last raw status bits.
+ */
+struct img_ir_priv_raw {
+	struct rc_dev		*rdev;
+	struct timer_list	timer;
+	u32			last_status;
+};
+
+static inline bool img_ir_raw_enabled(struct img_ir_priv_raw *raw)
+{
+	return raw->rdev;
+};
+
+void img_ir_isr_raw(struct img_ir_priv *priv, u32 irq_status);
+void img_ir_setup_raw(struct img_ir_priv *priv);
+int img_ir_probe_raw(struct img_ir_priv *priv);
+void img_ir_remove_raw(struct img_ir_priv *priv);
+
+#else
+
+struct img_ir_priv_raw {
+};
+static inline bool img_ir_raw_enabled(struct img_ir_priv_raw *raw)
+{
+	return false;
+};
+static inline void img_ir_isr_raw(struct img_ir_priv *priv, u32 irq_status)
+{
+}
+static inline void img_ir_setup_raw(struct img_ir_priv *priv)
+{
+}
+static inline int img_ir_probe_raw(struct img_ir_priv *priv)
+{
+	return -ENODEV;
+}
+static inline void img_ir_remove_raw(struct img_ir_priv *priv)
+{
+}
+
+#endif /* CONFIG_IR_IMG_RAW */
+
+#endif /* _IMG_IR_RAW_H_ */