[media] media: rc: add driver for Amlogic Meson IR remote receiver

Amlogic Meson SoCs include a infrared remote control receiver that can
operate in two modes: "NEC" mode in which the hardware decodes frames
using the NEC IR protocol, and "general" mode in which the receiver
simply reports the duration of pulses and spaces for software
decoding.

This is a driver for the IR receiver that implements software decoding
of received frames.

Signed-off-by: Beniamino Galvani <[e-mail]>
Acked-by: Carlo Caione <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

MAINTAINERS

···
 M:	Carlo Caione <[e-mail]>
 L:	[e-mail] (moderated for non-subscribers)
 S:	Maintained
+F:	drivers/media/rc/meson-ir.c
 N:	meson[x68]
 
 ARM/ATMEL AT91RM9200 AND AT91SAM ARM ARCHITECTURES

drivers/media/rc/Kconfig

···
 	   To compile this driver as a module, choose M here: the
 	   module will be called fintek-cir.
 
+config IR_MESON
+	tristate "Amlogic Meson IR remote receiver"
+	depends on RC_CORE
+	depends on ARCH_MESON || COMPILE_TEST
+	---help---
+	   Say Y if you want to use the IR remote receiver available
+	   on Amlogic Meson SoCs.
+
+	   To compile this driver as a module, choose M here: the
+	   module will be called meson-ir.
+
 config IR_NUVOTON
 	tristate "Nuvoton w836x7hg Consumer Infrared Transceiver"
 	depends on PNP

drivers/media/rc/Makefile

···
 obj-$(CONFIG_IR_ITE_CIR) += ite-cir.o
 obj-$(CONFIG_IR_MCEUSB) += mceusb.o
 obj-$(CONFIG_IR_FINTEK) += fintek-cir.o
+obj-$(CONFIG_IR_MESON) += meson-ir.o
 obj-$(CONFIG_IR_NUVOTON) += nuvoton-cir.o
 obj-$(CONFIG_IR_ENE) += ene_ir.o
 obj-$(CONFIG_IR_REDRAT3) += redrat3.o

drivers/media/rc/meson-ir.c

···
+/*
+ * Driver for Amlogic Meson IR remote receiver
+ *
+ * Copyright (C) 2014 Beniamino Galvani <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#include <media/rc-core.h>
+
+#define DRIVER_NAME		"meson-ir"
+
+#define IR_DEC_LDR_ACTIVE	0x00
+#define IR_DEC_LDR_IDLE		0x04
+#define IR_DEC_LDR_REPEAT	0x08
+#define IR_DEC_BIT_0		0x0c
+#define IR_DEC_REG0		0x10
+#define IR_DEC_FRAME		0x14
+#define IR_DEC_STATUS		0x18
+#define IR_DEC_REG1		0x1c
+
+#define REG0_RATE_MASK		(BIT(11) - 1)
+
+#define REG1_MODE_MASK		(BIT(7) | BIT(8))
+#define REG1_MODE_NEC		(0 << 7)
+#define REG1_MODE_GENERAL	(2 << 7)
+
+#define REG1_TIME_IV_SHIFT	16
+#define REG1_TIME_IV_MASK	((BIT(13) - 1) << REG1_TIME_IV_SHIFT)
+
+#define REG1_IRQSEL_MASK	(BIT(2) | BIT(3))
+#define REG1_IRQSEL_NEC_MODE	(0 << 2)
+#define REG1_IRQSEL_RISE_FALL	(1 << 2)
+#define REG1_IRQSEL_FALL	(2 << 2)
+#define REG1_IRQSEL_RISE	(3 << 2)
+
+#define REG1_RESET		BIT(0)
+#define REG1_ENABLE		BIT(15)
+
+#define STATUS_IR_DEC_IN	BIT(8)
+
+#define MESON_TRATE		10	/* us */
+
+struct meson_ir {
+	void __iomem	*reg;
+	struct rc_dev	*rc;
+	int		irq;
+	spinlock_t	lock;
+};
+
+static void meson_ir_set_mask(struct meson_ir *ir, unsigned int reg,
+			      u32 mask, u32 value)
+{
+	u32 data;
+
+	data = readl(ir->reg + reg);
+	data &= ~mask;
+	data |= (value & mask);
+	writel(data, ir->reg + reg);
+}
+
+static irqreturn_t meson_ir_irq(int irqno, void *dev_id)
+{
+	struct meson_ir *ir = dev_id;
+	u32 duration;
+	DEFINE_IR_RAW_EVENT(rawir);
+
+	spin_lock(&ir->lock);
+
+	duration = readl(ir->reg + IR_DEC_REG1);
+	duration = (duration & REG1_TIME_IV_MASK) >> REG1_TIME_IV_SHIFT;
+	rawir.duration = US_TO_NS(duration * MESON_TRATE);
+
+	rawir.pulse = !!(readl(ir->reg + IR_DEC_STATUS) & STATUS_IR_DEC_IN);
+
+	ir_raw_event_store_with_filter(ir->rc, &rawir);
+	ir_raw_event_handle(ir->rc);
+
+	spin_unlock(&ir->lock);
+
+	return IRQ_HANDLED;
+}
+
+static int meson_ir_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	struct resource *res;
+	const char *map_name;
+	struct meson_ir *ir;
+	int ret;
+
+	ir = devm_kzalloc(dev, sizeof(struct meson_ir), GFP_KERNEL);
+	if (!ir)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ir->reg = devm_ioremap_resource(dev, res);
+	if (IS_ERR(ir->reg)) {
+		dev_err(dev, "failed to map registers\n");
+		return PTR_ERR(ir->reg);
+	}
+
+	ir->irq = platform_get_irq(pdev, 0);
+	if (ir->irq < 0) {
+		dev_err(dev, "no irq resource\n");
+		return ir->irq;
+	}
+
+	ir->rc = rc_allocate_device();
+	if (!ir->rc) {
+		dev_err(dev, "failed to allocate rc device\n");
+		return -ENOMEM;
+	}
+
+	ir->rc->priv = ir;
+	ir->rc->input_name = DRIVER_NAME;
+	ir->rc->input_phys = DRIVER_NAME "/input0";
+	ir->rc->input_id.bustype = BUS_HOST;
+	map_name = of_get_property(node, "linux,rc-map-name", NULL);
+	ir->rc->map_name = map_name ? map_name : RC_MAP_EMPTY;
+	ir->rc->dev.parent = dev;
+	ir->rc->driver_type = RC_DRIVER_IR_RAW;
+	ir->rc->allowed_protocols = RC_BIT_ALL;
+	ir->rc->rx_resolution = US_TO_NS(MESON_TRATE);
+	ir->rc->timeout = MS_TO_NS(200);
+	ir->rc->driver_name = DRIVER_NAME;
+
+	spin_lock_init(&ir->lock);
+	platform_set_drvdata(pdev, ir);
+
+	ret = rc_register_device(ir->rc);
+	if (ret) {
+		dev_err(dev, "failed to register rc device\n");
+		goto out_free;
+	}
+
+	ret = devm_request_irq(dev, ir->irq, meson_ir_irq, 0, "ir-meson", ir);
+	if (ret) {
+		dev_err(dev, "failed to request irq\n");
+		goto out_unreg;
+	}
+
+	/* Reset the decoder */
+	meson_ir_set_mask(ir, IR_DEC_REG1, REG1_RESET, REG1_RESET);
+	meson_ir_set_mask(ir, IR_DEC_REG1, REG1_RESET, 0);
+	/* Set general operation mode */
+	meson_ir_set_mask(ir, IR_DEC_REG1, REG1_MODE_MASK, REG1_MODE_GENERAL);
+	/* Set rate */
+	meson_ir_set_mask(ir, IR_DEC_REG0, REG0_RATE_MASK, MESON_TRATE - 1);
+	/* IRQ on rising and falling edges */
+	meson_ir_set_mask(ir, IR_DEC_REG1, REG1_IRQSEL_MASK,
+			  REG1_IRQSEL_RISE_FALL);
+	/* Enable the decoder */
+	meson_ir_set_mask(ir, IR_DEC_REG1, REG1_ENABLE, REG1_ENABLE);
+
+	dev_info(dev, "receiver initialized\n");
+
+	return 0;
+out_unreg:
+	rc_unregister_device(ir->rc);
+	ir->rc = NULL;
+out_free:
+	rc_free_device(ir->rc);
+
+	return ret;
+}
+
+static int meson_ir_remove(struct platform_device *pdev)
+{
+	struct meson_ir *ir = platform_get_drvdata(pdev);
+	unsigned long flags;
+
+	/* Disable the decoder */
+	spin_lock_irqsave(&ir->lock, flags);
+	meson_ir_set_mask(ir, IR_DEC_REG1, REG1_ENABLE, 0);
+	spin_unlock_irqrestore(&ir->lock, flags);
+
+	rc_unregister_device(ir->rc);
+
+	return 0;
+}
+
+static const struct of_device_id meson_ir_match[] = {
+	{ .compatible = "amlogic,meson6-ir" },
+	{ },
+};
+
+static struct platform_driver meson_ir_driver = {
+	.probe		= meson_ir_probe,
+	.remove		= meson_ir_remove,
+	.driver = {
+		.name		= DRIVER_NAME,
+		.of_match_table	= meson_ir_match,
+	},
+};
+
+module_platform_driver(meson_ir_driver);
+
+MODULE_DESCRIPTION("Amlogic Meson IR remote receiver driver");
+MODULE_AUTHOR("Beniamino Galvani <[e-mail]>");
+MODULE_LICENSE("GPL v2");