1 files changed, 335 insertions, 0 deletions
diff --git a/drivers/media/rc/mtk-cir.c b/drivers/media/rc/mtk-cir.c
new file mode 100644
index 000000000000..f1e164e441e8
--- /dev/null
+++ b/drivers/media/rc/mtk-cir.c
@@ -0,0 +1,335 @@
+/*
+ * Driver for Mediatek IR Receiver Controller
+ *
+ * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com>
+ *
+ * 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/reset.h>
+#include <media/rc-core.h>
+
+#define MTK_IR_DEV KBUILD_MODNAME
+
+/* Register to enable PWM and IR */
+#define MTK_CONFIG_HIGH_REG       0x0c
+/* Enable IR pulse width detection */
+#define MTK_PWM_EN		  BIT(13)
+/* Enable IR hardware function */
+#define MTK_IR_EN		  BIT(0)
+
+/* Register to setting sample period */
+#define MTK_CONFIG_LOW_REG        0x10
+/* Field to set sample period */
+#define CHK_PERIOD		  DIV_ROUND_CLOSEST(MTK_IR_SAMPLE,  \
+						    MTK_IR_CLK_PERIOD)
+#define MTK_CHK_PERIOD            (((CHK_PERIOD) << 8) & (GENMASK(20, 8)))
+#define MTK_CHK_PERIOD_MASK	  (GENMASK(20, 8))
+
+/* Register to clear state of state machine */
+#define MTK_IRCLR_REG             0x20
+/* Bit to restart IR receiving */
+#define MTK_IRCLR		  BIT(0)
+
+/* Register containing pulse width data */
+#define MTK_CHKDATA_REG(i)        (0x88 + 4 * (i))
+#define MTK_WIDTH_MASK		  (GENMASK(7, 0))
+
+/* Register to enable IR interrupt */
+#define MTK_IRINT_EN_REG          0xcc
+/* Bit to enable interrupt */
+#define MTK_IRINT_EN		  BIT(0)
+
+/* Register to ack IR interrupt */
+#define MTK_IRINT_CLR_REG         0xd0
+/* Bit to clear interrupt status */
+#define MTK_IRINT_CLR		  BIT(0)
+
+/* Maximum count of samples */
+#define MTK_MAX_SAMPLES		  0xff
+/* Indicate the end of IR message */
+#define MTK_IR_END(v, p)	  ((v) == MTK_MAX_SAMPLES && (p) == 0)
+/* Number of registers to record the pulse width */
+#define MTK_CHKDATA_SZ		  17
+/* Source clock frequency */
+#define MTK_IR_BASE_CLK		  273000000
+/* Frequency after IR internal divider */
+#define MTK_IR_CLK_FREQ		  (MTK_IR_BASE_CLK / 4)
+/* Period for MTK_IR_CLK in ns*/
+#define MTK_IR_CLK_PERIOD	  DIV_ROUND_CLOSEST(1000000000ul,  \
+						    MTK_IR_CLK_FREQ)
+/* Sample period in ns */
+#define MTK_IR_SAMPLE		  (MTK_IR_CLK_PERIOD * 0xc00)
+
+/*
+ * struct mtk_ir -	This is the main datasructure for holding the state
+ *			of the driver
+ * @dev:		The device pointer
+ * @rc:			The rc instrance
+ * @irq:		The IRQ that we are using
+ * @base:		The mapped register i/o base
+ * @clk:		The clock that we are using
+ */
+struct mtk_ir {
+	struct device	*dev;
+	struct rc_dev	*rc;
+	void __iomem	*base;
+	int		irq;
+	struct clk	*clk;
+};
+
+static void mtk_w32_mask(struct mtk_ir *ir, u32 val, u32 mask, unsigned int reg)
+{
+	u32 tmp;
+
+	tmp = __raw_readl(ir->base + reg);
+	tmp = (tmp & ~mask) | val;
+	__raw_writel(tmp, ir->base + reg);
+}
+
+static void mtk_w32(struct mtk_ir *ir, u32 val, unsigned int reg)
+{
+	__raw_writel(val, ir->base + reg);
+}
+
+static u32 mtk_r32(struct mtk_ir *ir, unsigned int reg)
+{
+	return __raw_readl(ir->base + reg);
+}
+
+static inline void mtk_irq_disable(struct mtk_ir *ir, u32 mask)
+{
+	u32 val;
+
+	val = mtk_r32(ir, MTK_IRINT_EN_REG);
+	mtk_w32(ir, val & ~mask, MTK_IRINT_EN_REG);
+}
+
+static inline void mtk_irq_enable(struct mtk_ir *ir, u32 mask)
+{
+	u32 val;
+
+	val = mtk_r32(ir, MTK_IRINT_EN_REG);
+	mtk_w32(ir, val | mask, MTK_IRINT_EN_REG);
+}
+
+static irqreturn_t mtk_ir_irq(int irqno, void *dev_id)
+{
+	struct mtk_ir *ir = dev_id;
+	u8  wid = 0;
+	u32 i, j, val;
+	DEFINE_IR_RAW_EVENT(rawir);
+
+	/*
+	 * Reset decoder state machine explicitly is required
+	 * because 1) the longest duration for space MTK IR hardware
+	 * could record is not safely long. e.g  12ms if rx resolution
+	 * is 46us by default. There is still the risk to satisfying
+	 * every decoder to reset themselves through long enough
+	 * trailing spaces and 2) the IRQ handler guarantees that
+	 * start of IR message is always contained in and starting
+	 * from register MTK_CHKDATA_REG(0).
+	 */
+	ir_raw_event_reset(ir->rc);
+
+	/* First message must be pulse */
+	rawir.pulse = false;
+
+	/* Handle all pulse and space IR controller captures */
+	for (i = 0 ; i < MTK_CHKDATA_SZ ; i++) {
+		val = mtk_r32(ir, MTK_CHKDATA_REG(i));
+		dev_dbg(ir->dev, "@reg%d=0x%08x\n", i, val);
+
+		for (j = 0 ; j < 4 ; j++) {
+			wid = (val & (MTK_WIDTH_MASK << j * 8)) >> j * 8;
+			rawir.pulse = !rawir.pulse;
+			rawir.duration = wid * (MTK_IR_SAMPLE + 1);
+			ir_raw_event_store_with_filter(ir->rc, &rawir);
+		}
+	}
+
+	/*
+	 * The maximum number of edges the IR controller can
+	 * hold is MTK_CHKDATA_SZ * 4. So if received IR messages
+	 * is over the limit, the last incomplete IR message would
+	 * be appended trailing space and still would be sent into
+	 * ir-rc-raw to decode. That helps it is possible that it
+	 * has enough information to decode a scancode even if the
+	 * trailing end of the message is missing.
+	 */
+	if (!MTK_IR_END(wid, rawir.pulse)) {
+		rawir.pulse = false;
+		rawir.duration = MTK_MAX_SAMPLES * (MTK_IR_SAMPLE + 1);
+		ir_raw_event_store_with_filter(ir->rc, &rawir);
+	}
+
+	ir_raw_event_handle(ir->rc);
+
+	/*
+	 * Restart controller for the next receive that would
+	 * clear up all CHKDATA registers
+	 */
+	mtk_w32_mask(ir, 0x1, MTK_IRCLR, MTK_IRCLR_REG);
+
+	/* Clear interrupt status */
+	mtk_w32_mask(ir, 0x1, MTK_IRINT_CLR, MTK_IRINT_CLR_REG);
+
+	return IRQ_HANDLED;
+}
+
+static int mtk_ir_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *dn = dev->of_node;
+	struct resource *res;
+	struct mtk_ir *ir;
+	u32 val;
+	int ret = 0;
+	const char *map_name;
+
+	ir = devm_kzalloc(dev, sizeof(struct mtk_ir), GFP_KERNEL);
+	if (!ir)
+		return -ENOMEM;
+
+	ir->dev = dev;
+
+	if (!of_device_is_compatible(dn, "mediatek,mt7623-cir"))
+		return -ENODEV;
+
+	ir->clk = devm_clk_get(dev, "clk");
+	if (IS_ERR(ir->clk)) {
+		dev_err(dev, "failed to get a ir clock.\n");
+		return PTR_ERR(ir->clk);
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ir->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(ir->base)) {
+		dev_err(dev, "failed to map registers\n");
+		return PTR_ERR(ir->base);
+	}
+
+	ir->rc = devm_rc_allocate_device(dev, RC_DRIVER_IR_RAW);
+	if (!ir->rc) {
+		dev_err(dev, "failed to allocate device\n");
+		return -ENOMEM;
+	}
+
+	ir->rc->priv = ir;
+	ir->rc->input_name = MTK_IR_DEV;
+	ir->rc->input_phys = MTK_IR_DEV "/input0";
+	ir->rc->input_id.bustype = BUS_HOST;
+	ir->rc->input_id.vendor = 0x0001;
+	ir->rc->input_id.product = 0x0001;
+	ir->rc->input_id.version = 0x0001;
+	map_name = of_get_property(dn, "linux,rc-map-name", NULL);
+	ir->rc->map_name = map_name ?: RC_MAP_EMPTY;
+	ir->rc->dev.parent = dev;
+	ir->rc->driver_name = MTK_IR_DEV;
+	ir->rc->allowed_protocols = RC_BIT_ALL;
+	ir->rc->rx_resolution = MTK_IR_SAMPLE;
+	ir->rc->timeout = MTK_MAX_SAMPLES * (MTK_IR_SAMPLE + 1);
+
+	ret = devm_rc_register_device(dev, ir->rc);
+	if (ret) {
+		dev_err(dev, "failed to register rc device\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, ir);
+
+	ir->irq = platform_get_irq(pdev, 0);
+	if (ir->irq < 0) {
+		dev_err(dev, "no irq resource\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * Enable interrupt after proper hardware
+	 * setup and IRQ handler registration
+	 */
+	if (clk_prepare_enable(ir->clk)) {
+		dev_err(dev, "try to enable ir_clk failed\n");
+		ret = -EINVAL;
+		goto exit_clkdisable_clk;
+	}
+
+	mtk_irq_disable(ir, MTK_IRINT_EN);
+
+	ret = devm_request_irq(dev, ir->irq, mtk_ir_irq, 0, MTK_IR_DEV, ir);
+	if (ret) {
+		dev_err(dev, "failed request irq\n");
+		goto exit_clkdisable_clk;
+	}
+
+	/* Enable IR and PWM */
+	val = mtk_r32(ir, MTK_CONFIG_HIGH_REG);
+	val |= MTK_PWM_EN | MTK_IR_EN;
+	mtk_w32(ir, val, MTK_CONFIG_HIGH_REG);
+
+	/* Setting sample period */
+	mtk_w32_mask(ir, MTK_CHK_PERIOD, MTK_CHK_PERIOD_MASK,
+		     MTK_CONFIG_LOW_REG);
+
+	mtk_irq_enable(ir, MTK_IRINT_EN);
+
+	dev_info(dev, "Initialized MT7623 IR driver, sample period = %luus\n",
+		 DIV_ROUND_CLOSEST(MTK_IR_SAMPLE, 1000));
+
+	return 0;
+
+exit_clkdisable_clk:
+	clk_disable_unprepare(ir->clk);
+
+	return ret;
+}
+
+static int mtk_ir_remove(struct platform_device *pdev)
+{
+	struct mtk_ir *ir = platform_get_drvdata(pdev);
+
+	/*
+	 * Avoid contention between remove handler and
+	 * IRQ handler so that disabling IR interrupt and
+	 * waiting for pending IRQ handler to complete
+	 */
+	mtk_irq_disable(ir, MTK_IRINT_EN);
+	synchronize_irq(ir->irq);
+
+	clk_disable_unprepare(ir->clk);
+
+	return 0;
+}
+
+static const struct of_device_id mtk_ir_match[] = {
+	{ .compatible = "mediatek,mt7623-cir" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mtk_ir_match);
+
+static struct platform_driver mtk_ir_driver = {
+	.probe          = mtk_ir_probe,
+	.remove         = mtk_ir_remove,
+	.driver = {
+		.name = MTK_IR_DEV,
+		.of_match_table = mtk_ir_match,
+	},
+};
+
+module_platform_driver(mtk_ir_driver);
+
+MODULE_DESCRIPTION("Mediatek IR Receiver Controller Driver");
+MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
+MODULE_LICENSE("GPL");