1 files changed, 453 insertions, 0 deletions
diff --git a/drivers/media/rc/mtk-cir.c b/drivers/media/rc/mtk-cir.c
new file mode 100644
index 0000000000..4e294e59d3
--- /dev/null
+++ b/drivers/media/rc/mtk-cir.c
@@ -0,0 +1,453 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Mediatek IR Receiver Controller
+ *
+ * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.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
+
+/* Bit to enable IR pulse width detection */
+#define MTK_PWM_EN		  BIT(13)
+
+/*
+ * Register to setting ok count whose unit based on hardware sampling period
+ * indicating IR receiving completion and then making IRQ fires
+ */
+#define MTK_OK_COUNT_MASK	  (GENMASK(22, 16))
+#define MTK_OK_COUNT(x)		  ((x) << 16)
+
+/* Bit to enable IR hardware function */
+#define MTK_IR_EN		  BIT(0)
+
+/* Bit to restart IR receiving */
+#define MTK_IRCLR		  BIT(0)
+
+/* Fields containing pulse width data */
+#define MTK_WIDTH_MASK		  (GENMASK(7, 0))
+
+/* IR threshold */
+#define MTK_IRTHD		 0x14
+#define MTK_DG_CNT_MASK		 (GENMASK(12, 8))
+#define MTK_DG_CNT(x)		 ((x) << 8)
+
+/* Bit to enable interrupt */
+#define MTK_IRINT_EN		  BIT(0)
+
+/* 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
+/* Sample period in us */
+#define MTK_IR_SAMPLE		  46
+
+enum mtk_fields {
+	/* Register to setting software sampling period */
+	MTK_CHK_PERIOD,
+	/* Register to setting hardware sampling period */
+	MTK_HW_PERIOD,
+};
+
+enum mtk_regs {
+	/* Register to clear state of state machine */
+	MTK_IRCLR_REG,
+	/* Register containing pulse width data */
+	MTK_CHKDATA_REG,
+	/* Register to enable IR interrupt */
+	MTK_IRINT_EN_REG,
+	/* Register to ack IR interrupt */
+	MTK_IRINT_CLR_REG
+};
+
+static const u32 mt7623_regs[] = {
+	[MTK_IRCLR_REG] =	0x20,
+	[MTK_CHKDATA_REG] =	0x88,
+	[MTK_IRINT_EN_REG] =	0xcc,
+	[MTK_IRINT_CLR_REG] =	0xd0,
+};
+
+static const u32 mt7622_regs[] = {
+	[MTK_IRCLR_REG] =	0x18,
+	[MTK_CHKDATA_REG] =	0x30,
+	[MTK_IRINT_EN_REG] =	0x1c,
+	[MTK_IRINT_CLR_REG] =	0x20,
+};
+
+struct mtk_field_type {
+	u32 reg;
+	u8 offset;
+	u32 mask;
+};
+
+/*
+ * struct mtk_ir_data -	This is the structure holding all differences among
+			various hardwares
+ * @regs:		The pointer to the array holding registers offset
+ * @fields:		The pointer to the array holding fields location
+ * @div:		The internal divisor for the based reference clock
+ * @ok_count:		The count indicating the completion of IR data
+ *			receiving when count is reached
+ * @hw_period:		The value indicating the hardware sampling period
+ */
+struct mtk_ir_data {
+	const u32 *regs;
+	const struct mtk_field_type *fields;
+	u8 div;
+	u8 ok_count;
+	u32 hw_period;
+};
+
+static const struct mtk_field_type mt7623_fields[] = {
+	[MTK_CHK_PERIOD] = {0x10, 8, GENMASK(20, 8)},
+	[MTK_HW_PERIOD] = {0x10, 0, GENMASK(7, 0)},
+};
+
+static const struct mtk_field_type mt7622_fields[] = {
+	[MTK_CHK_PERIOD] = {0x24, 0, GENMASK(24, 0)},
+	[MTK_HW_PERIOD] = {0x10, 0, GENMASK(24, 0)},
+};
+
+/*
+ * struct mtk_ir -	This is the main datasructure for holding the state
+ *			of the driver
+ * @dev:		The device pointer
+ * @rc:			The rc instrance
+ * @base:		The mapped register i/o base
+ * @irq:		The IRQ that we are using
+ * @clk:		The clock that IR internal is using
+ * @bus:		The clock that software decoder is using
+ * @data:		Holding specific data for vaious platform
+ */
+struct mtk_ir {
+	struct device	*dev;
+	struct rc_dev	*rc;
+	void __iomem	*base;
+	int		irq;
+	struct clk	*clk;
+	struct clk	*bus;
+	const struct mtk_ir_data *data;
+};
+
+static inline u32 mtk_chkdata_reg(struct mtk_ir *ir, u32 i)
+{
+	return ir->data->regs[MTK_CHKDATA_REG] + 4 * i;
+}
+
+static inline u32 mtk_chk_period(struct mtk_ir *ir)
+{
+	u32 val;
+
+	/*
+	 * Period for software decoder used in the
+	 * unit of raw software sampling
+	 */
+	val = DIV_ROUND_CLOSEST(clk_get_rate(ir->bus),
+				USEC_PER_SEC * ir->data->div / MTK_IR_SAMPLE);
+
+	dev_dbg(ir->dev, "@pwm clk  = \t%lu\n",
+		clk_get_rate(ir->bus) / ir->data->div);
+	dev_dbg(ir->dev, "@chkperiod = %08x\n", val);
+
+	return val;
+}
+
+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, ir->data->regs[MTK_IRINT_EN_REG]);
+	mtk_w32(ir, val & ~mask, ir->data->regs[MTK_IRINT_EN_REG]);
+}
+
+static inline void mtk_irq_enable(struct mtk_ir *ir, u32 mask)
+{
+	u32 val;
+
+	val = mtk_r32(ir, ir->data->regs[MTK_IRINT_EN_REG]);
+	mtk_w32(ir, val | mask, ir->data->regs[MTK_IRINT_EN_REG]);
+}
+
+static irqreturn_t mtk_ir_irq(int irqno, void *dev_id)
+{
+	struct ir_raw_event rawir = {};
+	struct mtk_ir *ir = dev_id;
+	u32 i, j, val;
+	u8 wid;
+
+	/*
+	 * Each pulse and space is encoded as a single byte, each byte
+	 * alternating between pulse and space. If a pulse or space is longer
+	 * than can be encoded in a single byte, it is encoded as the maximum
+	 * value 0xff.
+	 *
+	 * If a space is longer than ok_count (about 23ms), the value is
+	 * encoded as zero, and all following bytes are zero. Any IR that
+	 * follows will be presented in the next interrupt.
+	 *
+	 * If there are more than 68 (=MTK_CHKDATA_SZ * 4) pulses and spaces,
+	 * then the only the first 68 will be presented; the rest is lost.
+	 */
+
+	/* Handle all pulse and space IR controller captures */
+	for (i = 0 ; i < MTK_CHKDATA_SZ ; i++) {
+		val = mtk_r32(ir, mtk_chkdata_reg(ir, i));
+		dev_dbg(ir->dev, "@reg%d=0x%08x\n", i, val);
+
+		for (j = 0 ; j < 4 ; j++) {
+			wid = val & MTK_WIDTH_MASK;
+			val >>= 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, ir->data->regs[MTK_IRCLR_REG]);
+
+	/* Clear interrupt status */
+	mtk_w32_mask(ir, 0x1, MTK_IRINT_CLR,
+		     ir->data->regs[MTK_IRINT_CLR_REG]);
+
+	return IRQ_HANDLED;
+}
+
+static const struct mtk_ir_data mt7623_data = {
+	.regs = mt7623_regs,
+	.fields = mt7623_fields,
+	.ok_count = 3,
+	.hw_period = 0xff,
+	.div	= 4,
+};
+
+static const struct mtk_ir_data mt7622_data = {
+	.regs = mt7622_regs,
+	.fields = mt7622_fields,
+	.ok_count = 3,
+	.hw_period = 0xffff,
+	.div	= 32,
+};
+
+static const struct of_device_id mtk_ir_match[] = {
+	{ .compatible = "mediatek,mt7623-cir", .data = &mt7623_data},
+	{ .compatible = "mediatek,mt7622-cir", .data = &mt7622_data},
+	{},
+};
+MODULE_DEVICE_TABLE(of, mtk_ir_match);
+
+static int mtk_ir_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *dn = dev->of_node;
+	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;
+	ir->data = of_device_get_match_data(dev);
+
+	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);
+	}
+
+	ir->bus = devm_clk_get(dev, "bus");
+	if (IS_ERR(ir->bus)) {
+		/*
+		 * For compatibility with older device trees try unnamed
+		 * ir->bus uses the same clock as ir->clock.
+		 */
+		ir->bus = ir->clk;
+	}
+
+	ir->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ir->base))
+		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->device_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_PROTO_BIT_ALL_IR_DECODER;
+	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)
+		return -ENODEV;
+
+	if (clk_prepare_enable(ir->clk)) {
+		dev_err(dev, "try to enable ir_clk failed\n");
+		return -EINVAL;
+	}
+
+	if (clk_prepare_enable(ir->bus)) {
+		dev_err(dev, "try to enable ir_clk failed\n");
+		ret = -EINVAL;
+		goto exit_clkdisable_clk;
+	}
+
+	/*
+	 * Enable interrupt after proper hardware
+	 * setup and IRQ handler registration
+	 */
+	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_bus;
+	}
+
+	/*
+	 * Setup software sample period as the reference of software decoder
+	 */
+	val = (mtk_chk_period(ir) << ir->data->fields[MTK_CHK_PERIOD].offset) &
+	       ir->data->fields[MTK_CHK_PERIOD].mask;
+	mtk_w32_mask(ir, val, ir->data->fields[MTK_CHK_PERIOD].mask,
+		     ir->data->fields[MTK_CHK_PERIOD].reg);
+
+	/*
+	 * Setup hardware sampling period used to setup the proper timeout for
+	 * indicating end of IR receiving completion
+	 */
+	val = (ir->data->hw_period << ir->data->fields[MTK_HW_PERIOD].offset) &
+	       ir->data->fields[MTK_HW_PERIOD].mask;
+	mtk_w32_mask(ir, val, ir->data->fields[MTK_HW_PERIOD].mask,
+		     ir->data->fields[MTK_HW_PERIOD].reg);
+
+	/* Set de-glitch counter */
+	mtk_w32_mask(ir, MTK_DG_CNT(1), MTK_DG_CNT_MASK, MTK_IRTHD);
+
+	/* Enable IR and PWM */
+	val = mtk_r32(ir, MTK_CONFIG_HIGH_REG) & ~MTK_OK_COUNT_MASK;
+	val |= MTK_OK_COUNT(ir->data->ok_count) |  MTK_PWM_EN | MTK_IR_EN;
+	mtk_w32(ir, val, MTK_CONFIG_HIGH_REG);
+
+	mtk_irq_enable(ir, MTK_IRINT_EN);
+
+	dev_info(dev, "Initialized MT7623 IR driver, sample period = %dus\n",
+		 MTK_IR_SAMPLE);
+
+	return 0;
+
+exit_clkdisable_bus:
+	clk_disable_unprepare(ir->bus);
+exit_clkdisable_clk:
+	clk_disable_unprepare(ir->clk);
+
+	return ret;
+}
+
+static void 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->bus);
+	clk_disable_unprepare(ir->clk);
+}
+
+static struct platform_driver mtk_ir_driver = {
+	.probe          = mtk_ir_probe,
+	.remove_new     = 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");