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From:   Martin Kepplinger <martin.kepplinger@puri.sm>
To:     laurent.pinchart@ideasonboard.com, mchehab@kernel.org,
        robh@kernel.org
Cc:     shawnguo@kernel.org, kernel@pengutronix.de, festevam@gmail.com,
        linux-imx@nxp.com, slongerbeam@gmail.com, kernel@puri.sm,
        krzk@kernel.org, linux-media@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, linux-staging@lists.linux.dev,
        Martin Kepplinger <martin.kepplinger@puri.sm>
Subject: [PATCH v1 2/3] media: imx: add a driver for i.MX8MQ mipi csi rx phy and controller
Date:   Thu, 27 May 2021 09:54:06 +0200
Message-Id: <20210527075407.3180744-3-martin.kepplinger@puri.sm>
In-Reply-To: <20210527075407.3180744-1-martin.kepplinger@puri.sm>
References: <20210527075407.3180744-1-martin.kepplinger@puri.sm>
Content-Transfer-Encoding: 8bit
Precedence: bulk

The i.MX8MQ SoC includes a different MIPI CSI receiver than i.MX8MM so
add a driver to support it.

Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
---
 drivers/staging/media/imx/Makefile           |    1 +
 drivers/staging/media/imx/imx8mq-mipi-csi2.c | 1023 ++++++++++++++++++
 2 files changed, 1024 insertions(+)
 create mode 100644 drivers/staging/media/imx/imx8mq-mipi-csi2.c

diff --git a/drivers/staging/media/imx/Makefile b/drivers/staging/media/imx/Makefile
index 6ac33275cc97..19c2fc54d424 100644
--- a/drivers/staging/media/imx/Makefile
+++ b/drivers/staging/media/imx/Makefile
@@ -16,3 +16,4 @@ obj-$(CONFIG_VIDEO_IMX_CSI) += imx6-mipi-csi2.o
 
 obj-$(CONFIG_VIDEO_IMX7_CSI) += imx7-media-csi.o
 obj-$(CONFIG_VIDEO_IMX7_CSI) += imx7-mipi-csis.o
+obj-$(CONFIG_VIDEO_IMX7_CSI) += imx8mq-mipi-csi2.o
diff --git a/drivers/staging/media/imx/imx8mq-mipi-csi2.c b/drivers/staging/media/imx/imx8mq-mipi-csi2.c
new file mode 100644
index 000000000000..67b99be3e804
--- /dev/null
+++ b/drivers/staging/media/imx/imx8mq-mipi-csi2.c
@@ -0,0 +1,1023 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Freescale i.MX8MQ SoC series MIPI-CSI receiver driver
+ *
+ * Copyright (C) 2021 Purism SPC
+ * Copyright (C) 2019 Linaro Ltd
+ * Copyright (C) 2015-2016 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright (C) 2011 - 2013 Samsung Electronics Co., Ltd.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
+#include <linux/spinlock.h>
+#include <linux/interconnect.h>
+
+#include <media/v4l2-common.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-fwnode.h>
+#include <media/v4l2-mc.h>
+#include <media/v4l2-subdev.h>
+
+#define MIPI_CSI2_DRIVER_NAME			"imx8mq-mipi-csi2"
+#define MIPI_CSI2_SUBDEV_NAME			MIPI_CSI2_DRIVER_NAME
+
+#define MIPI_CSI2_PAD_SINK			0
+#define MIPI_CSI2_PAD_SOURCE			1
+#define MIPI_CSI2_PADS_NUM			2
+
+#define MIPI_CSI2_DEF_PIX_WIDTH			640
+#define MIPI_CSI2_DEF_PIX_HEIGHT		480
+
+#define MIPI_CSI2_RX_CSR_1_BASE_ADDR		0x30A70000
+#define MIPI_CSI2_RX_CSR_1_GPR_REG		0x88
+#define MIPI_CSI2_RX_CSR_1_HW_RESET_REG		0x4C
+#define MIPI_CSI2_RX_CSR_1_HW_RESET_VAL		7
+#define MIPI_CSI2_RX_CSR_2_BASE_ADDR		0x30B60000
+#define MIPI_CSI2_RX_CSR_2_GPR_REG		0xA4
+#define MIPI_CSI2_RX_CSR_2_HW_RESET_REG		0x50
+#define MIPI_CSI2_RX_CSR_2_HW_RESET_VAL		7
+
+/* Register map definition */
+
+/* i.MX8MQ CSI-2 controller CSR */
+#define CSI2RX_CFG_NUM_LANES			0x100
+#define CSI2RX_CFG_DISABLE_DATA_LANES		0x104
+#define CSI2RX_BIT_ERR				0x108
+#define CSI2RX_IRQ_STATUS			0x10C
+#define CSI2RX_IRQ_MASK				0x110
+#define CSI2RX_ULPS_STATUS			0x114
+#define CSI2RX_PPI_ERRSOT_HS			0x118
+#define CSI2RX_PPI_ERRSOTSYNC_HS		0x11C
+#define CSI2RX_PPI_ERRESC			0x120
+#define CSI2RX_PPI_ERRSYNCESC			0x124
+#define CSI2RX_PPI_ERRCONTROL			0x128
+#define CSI2RX_CFG_DISABLE_PAYLOAD_0		0x12C
+#define CSI2RX_CFG_DISABLE_PAYLOAD_1		0x130
+
+enum {
+	ST_POWERED	= 1,
+	ST_STREAMING	= 2,
+	ST_SUSPENDED	= 4,
+};
+
+static const char * const mipi_csi2_clk_id[] = {
+	"core",
+	"esc",
+	"pxl",
+	"clko2",
+};
+
+#define	GPR_CSI2_1_RX_ENABLE		BIT(13)
+#define	GPR_CSI2_1_VID_INTFC_ENB	BIT(12)
+#define	GPR_CSI2_1_HSEL			BIT(10)
+#define	GPR_CSI2_1_CONT_CLK_MODE	BIT(8)
+#define	GPR_CSI2_1_S_PRG_RXHS_SETTLE(x)	(((x) & 0x3F) << 2)
+
+struct csi_state {
+	struct device *dev;
+	void __iomem *regs;
+	struct clk_bulk_data *clks;
+	struct reset_control *mrst;
+	struct regulator *mipi_phy_regulator;
+	u8 index;
+
+	struct v4l2_subdev sd;
+	struct media_pad pads[MIPI_CSI2_PADS_NUM];
+	struct v4l2_async_notifier notifier;
+	struct v4l2_subdev *src_sd;
+
+	struct v4l2_fwnode_bus_mipi_csi2 bus;
+	u32 hs_settle;
+	u32 clk_settle;
+
+	struct mutex lock;	/* Protect csi2_fmt, format_mbus and state */
+	const struct csi2_pix_format *csi2_fmt;
+	struct v4l2_mbus_framefmt format_mbus;
+	u32 state;
+
+	struct regmap *hw_reset;
+	u8 hw_reset_reg;
+
+	struct regmap *phy_gpr;
+	u8 phy_gpr_reg;
+
+	u32 send_level;
+
+	struct icc_path			*icc_path;
+	s32				icc_path_bw;
+};
+
+/* -----------------------------------------------------------------------------
+ * Format helpers
+ */
+
+struct csi2_pix_format {
+	u32 code;
+	u8 width;
+};
+
+static const struct csi2_pix_format mipi_csi2_formats[] = {
+	/* RAW (Bayer and greyscale) formats. */
+	{
+		.code = MEDIA_BUS_FMT_SBGGR8_1X8,
+		.width = 8,
+	}, {
+		.code = MEDIA_BUS_FMT_SGBRG8_1X8,
+		.width = 8,
+	}, {
+		.code = MEDIA_BUS_FMT_SGRBG8_1X8,
+		.width = 8,
+	}, {
+		.code = MEDIA_BUS_FMT_SRGGB8_1X8,
+		.width = 8,
+	}, {
+		.code = MEDIA_BUS_FMT_Y8_1X8,
+		.width = 8,
+	}, {
+		.code = MEDIA_BUS_FMT_SBGGR10_1X10,
+		.width = 10,
+	}, {
+		.code = MEDIA_BUS_FMT_SGBRG10_1X10,
+		.width = 10,
+	}, {
+		.code = MEDIA_BUS_FMT_SGRBG10_1X10,
+		.width = 10,
+	}, {
+		.code = MEDIA_BUS_FMT_SRGGB10_1X10,
+		.width = 10,
+	}, {
+		.code = MEDIA_BUS_FMT_Y10_1X10,
+		.width = 10,
+	}, {
+		.code = MEDIA_BUS_FMT_SBGGR12_1X12,
+		.width = 12,
+	}, {
+		.code = MEDIA_BUS_FMT_SGBRG12_1X12,
+		.width = 12,
+	}, {
+		.code = MEDIA_BUS_FMT_SGRBG12_1X12,
+		.width = 12,
+	}, {
+		.code = MEDIA_BUS_FMT_SRGGB12_1X12,
+		.width = 12,
+	}, {
+		.code = MEDIA_BUS_FMT_Y12_1X12,
+		.width = 12,
+	}, {
+		.code = MEDIA_BUS_FMT_SBGGR14_1X14,
+		.width = 14,
+	}, {
+		.code = MEDIA_BUS_FMT_SGBRG14_1X14,
+		.width = 14,
+	}, {
+		.code = MEDIA_BUS_FMT_SGRBG14_1X14,
+		.width = 14,
+	}, {
+		.code = MEDIA_BUS_FMT_SRGGB14_1X14,
+		.width = 14,
+	}
+};
+
+static const struct csi2_pix_format *find_csi2_format(u32 code)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(mipi_csi2_formats); i++)
+		if (code == mipi_csi2_formats[i].code)
+			return &mipi_csi2_formats[i];
+	return NULL;
+}
+
+/* -----------------------------------------------------------------------------
+ * Hardware configuration
+ */
+
+static inline u32 mipi_csi2_read(struct csi_state *state, u32 reg)
+{
+	return readl(state->regs + reg);
+}
+
+static inline void mipi_csi2_write(struct csi_state *state, u32 reg, u32 val)
+{
+	writel(val, state->regs + reg);
+}
+
+static void mipi_csi2_sw_reset(struct csi_state *state)
+{
+	struct device *dev = state->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *node;
+	phandle phandle;
+	int ret;
+
+	dev_dbg(dev, "%s: starting\n", __func__);
+
+	ret = of_property_read_u32(np, "phy-reset", &phandle);
+	if (ret) {
+		dev_info(dev, "no csis-hw-reset property found: %d\n", ret);
+		return;
+	}
+
+	node = of_find_node_by_phandle(phandle);
+	if (!node) {
+		ret = PTR_ERR(node);
+		dev_dbg(dev, "not find src node by phandle: %d\n", ret);
+	}
+	state->hw_reset = syscon_node_to_regmap(node);
+	if (IS_ERR(state->hw_reset)) {
+		ret = PTR_ERR(state->hw_reset);
+		dev_err(dev, "failed to get src regmap: %d\n", ret);
+	}
+	of_node_put(node);
+	if (ret < 0)
+		return;
+
+	/* reset imx8mq mipi phy */
+	regmap_update_bits(state->hw_reset, state->hw_reset_reg, 7, 7);
+	msleep(20);
+}
+
+static void mipi_csi2_system_enable(struct csi_state *state, int on)
+{
+	struct device *dev = state->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *node;
+	phandle phandle;
+	int ret;
+
+	if (!on) {
+		/* Disable Data lanes */
+		mipi_csi2_write(state, CSI2RX_CFG_DISABLE_DATA_LANES, 0xf);
+		return;
+	}
+
+	ret = of_property_read_u32(np, "phy-gpr", &phandle);
+	if (ret) {
+		dev_info(dev, "no phy-gpr property found\n");
+		return;
+	}
+
+	node = of_find_node_by_phandle(phandle);
+	if (!node) {
+		dev_dbg(dev, "not find gpr node by phandle\n");
+		ret = PTR_ERR(node);
+	}
+	state->phy_gpr = syscon_node_to_regmap(node);
+	if (IS_ERR(state->phy_gpr)) {
+		dev_err(dev, "failed to get gpr regmap\n");
+		ret = PTR_ERR(state->phy_gpr);
+	}
+	of_node_put(node);
+	if (ret < 0)
+		return;
+
+	regmap_update_bits(state->phy_gpr,
+			   state->phy_gpr_reg,
+			   0x3FFF,
+			   GPR_CSI2_1_RX_ENABLE |
+			   GPR_CSI2_1_VID_INTFC_ENB |
+			   GPR_CSI2_1_HSEL |
+			   GPR_CSI2_1_CONT_CLK_MODE |
+			   GPR_CSI2_1_S_PRG_RXHS_SETTLE(state->hs_settle));
+
+	dev_dbg(dev, "%s: hs_settle: 0x%X\n", __func__, state->hs_settle);
+}
+
+static void mipi_csi2_set_params(struct csi_state *state)
+{
+	int lanes = state->bus.num_data_lanes;
+	u32 val = 0;
+	int i;
+
+	/* Lanes */
+	mipi_csi2_write(state, CSI2RX_CFG_NUM_LANES, lanes - 1);
+
+	for (i = 0; i < lanes; i++)
+		val |= (1 << i);
+
+	val = 0xF & ~val;
+	mipi_csi2_write(state, CSI2RX_CFG_DISABLE_DATA_LANES, val);
+
+	dev_dbg(state->dev, "imx8mq: CSI2RX_CFG_DISABLE_DATA_LANES: 0x%X\n", val);
+
+	/* Mask interrupt */
+	// Don't let ULPS (ultra-low power status) interrupts flood
+	mipi_csi2_write(state, CSI2RX_IRQ_MASK, 0x1ff);
+
+	mipi_csi2_write(state, 0x180, 1);
+	/* vid_vc */
+	mipi_csi2_write(state, 0x184, 1);
+	mipi_csi2_write(state, 0x188, state->send_level);
+}
+
+static int mipi_csi2_clk_enable(struct csi_state *state)
+{
+	return clk_bulk_prepare_enable(ARRAY_SIZE(mipi_csi2_clk_id), state->clks);
+}
+
+static void mipi_csi2_clk_disable(struct csi_state *state)
+{
+	clk_bulk_disable_unprepare(ARRAY_SIZE(mipi_csi2_clk_id), state->clks);
+}
+
+static int mipi_csi2_clk_get(struct csi_state *state)
+{
+	unsigned int i;
+	int ret;
+
+	state->clks = devm_kcalloc(state->dev, ARRAY_SIZE(mipi_csi2_clk_id),
+				   sizeof(*state->clks), GFP_KERNEL);
+
+	if (!state->clks)
+		return -ENOMEM;
+
+	for (i = 0; i < ARRAY_SIZE(mipi_csi2_clk_id); i++)
+		state->clks[i].id = mipi_csi2_clk_id[i];
+
+	ret = devm_clk_bulk_get(state->dev, ARRAY_SIZE(mipi_csi2_clk_id),
+				state->clks);
+	return ret;
+}
+
+static void mipi_csi2_start_stream(struct csi_state *state)
+{
+	mipi_csi2_sw_reset(state);
+	mipi_csi2_set_params(state);
+	mipi_csi2_system_enable(state, true);
+}
+
+static void mipi_csi2_stop_stream(struct csi_state *state)
+{
+	mipi_csi2_system_enable(state, false);
+}
+
+/* -----------------------------------------------------------------------------
+ * V4L2 subdev operations
+ */
+
+static struct csi_state *mipi_sd_to_csi2_state(struct v4l2_subdev *sdev)
+{
+	return container_of(sdev, struct csi_state, sd);
+}
+
+static int mipi_csi2_s_stream(struct v4l2_subdev *sd, int enable)
+{
+	struct csi_state *state = mipi_sd_to_csi2_state(sd);
+	int ret;
+
+	mipi_csi2_write(state, CSI2RX_IRQ_MASK, 0x008);
+
+	dev_dbg(state->dev, "%s: enable: %d\n", __func__, enable);
+
+	if (enable) {
+		ret = pm_runtime_get_sync(state->dev);
+		if (ret < 0) {
+			pm_runtime_put_noidle(state->dev);
+			return ret;
+		}
+		ret = v4l2_subdev_call(state->src_sd, core, s_power, 1);
+		if (ret < 0 && ret != -ENOIOCTLCMD)
+			goto done;
+	}
+
+	mutex_lock(&state->lock);
+
+	if (enable) {
+		if (state->state & ST_SUSPENDED) {
+			ret = -EBUSY;
+			goto unlock;
+		}
+
+		mipi_csi2_start_stream(state);
+		ret = v4l2_subdev_call(state->src_sd, video, s_stream, 1);
+		if (ret < 0)
+			goto unlock;
+
+		state->state |= ST_STREAMING;
+	} else {
+		v4l2_subdev_call(state->src_sd, video, s_stream, 0);
+		ret = v4l2_subdev_call(state->src_sd, core, s_power, 0);
+		if (ret == -ENOIOCTLCMD)
+			ret = 0;
+		mipi_csi2_stop_stream(state);
+		state->state &= ~ST_STREAMING;
+	}
+
+unlock:
+	mutex_unlock(&state->lock);
+
+done:
+	if (!enable || ret < 0)
+		pm_runtime_put(state->dev);
+
+	return ret;
+}
+
+static struct v4l2_mbus_framefmt *
+mipi_csi2_get_format(struct csi_state *state,
+		     struct v4l2_subdev_pad_config *cfg,
+		     enum v4l2_subdev_format_whence which,
+		     unsigned int pad)
+{
+	if (which == V4L2_SUBDEV_FORMAT_TRY)
+		return v4l2_subdev_get_try_format(&state->sd, cfg, pad);
+
+	return &state->format_mbus;
+}
+
+static int mipi_csi2_init_cfg(struct v4l2_subdev *sd,
+			      struct v4l2_subdev_pad_config *cfg)
+{
+	struct csi_state *state = mipi_sd_to_csi2_state(sd);
+	struct v4l2_mbus_framefmt *fmt_sink;
+	struct v4l2_mbus_framefmt *fmt_source;
+	enum v4l2_subdev_format_whence which;
+
+	which = cfg ? V4L2_SUBDEV_FORMAT_TRY : V4L2_SUBDEV_FORMAT_ACTIVE;
+	fmt_sink = mipi_csi2_get_format(state, cfg, which, MIPI_CSI2_PAD_SINK);
+
+	fmt_sink->code = MEDIA_BUS_FMT_SGBRG10_1X10;
+	fmt_sink->width = MIPI_CSI2_DEF_PIX_WIDTH;
+	fmt_sink->height = MIPI_CSI2_DEF_PIX_HEIGHT;
+	fmt_sink->field = V4L2_FIELD_NONE;
+
+	fmt_sink->colorspace = V4L2_COLORSPACE_RAW;
+	fmt_sink->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(fmt_sink->colorspace);
+	fmt_sink->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(fmt_sink->colorspace);
+	fmt_sink->quantization =
+		V4L2_MAP_QUANTIZATION_DEFAULT(false, fmt_sink->colorspace,
+					      fmt_sink->ycbcr_enc);
+
+	/*
+	 * When called from mipi_csi2_subdev_init() to initialize the active
+	 * configuration, cfg is NULL, which indicates there's no source pad
+	 * configuration to set.
+	 */
+	if (!cfg)
+		return 0;
+
+	fmt_source = mipi_csi2_get_format(state, cfg, which, MIPI_CSI2_PAD_SOURCE);
+	*fmt_source = *fmt_sink;
+
+	return 0;
+}
+
+static int mipi_csi2_get_fmt(struct v4l2_subdev *sd,
+			     struct v4l2_subdev_pad_config *cfg,
+			     struct v4l2_subdev_format *sdformat)
+{
+	struct csi_state *state = mipi_sd_to_csi2_state(sd);
+	struct v4l2_mbus_framefmt *fmt;
+
+	fmt = mipi_csi2_get_format(state, cfg, sdformat->which, sdformat->pad);
+
+	mutex_lock(&state->lock);
+	sdformat->format = *fmt;
+	mutex_unlock(&state->lock);
+
+	return 0;
+}
+
+static int mipi_csi2_enum_mbus_code(struct v4l2_subdev *sd,
+				    struct v4l2_subdev_pad_config *cfg,
+				    struct v4l2_subdev_mbus_code_enum *code)
+{
+	struct csi_state *state = mipi_sd_to_csi2_state(sd);
+
+	/*
+	 * We can't transcode in any way, the source format is identical
+	 * to the sink format.
+	 */
+	if (code->pad == MIPI_CSI2_PAD_SOURCE) {
+		struct v4l2_mbus_framefmt *fmt;
+
+		if (code->index > 0)
+			return -EINVAL;
+
+		fmt = mipi_csi2_get_format(state, cfg, code->which, code->pad);
+		code->code = fmt->code;
+		return 0;
+	}
+
+	if (code->pad != MIPI_CSI2_PAD_SINK)
+		return -EINVAL;
+
+	if (code->index >= ARRAY_SIZE(mipi_csi2_formats))
+		return -EINVAL;
+
+	code->code = mipi_csi2_formats[code->index].code;
+
+	return 0;
+}
+
+static int mipi_csi2_set_fmt(struct v4l2_subdev *sd,
+			     struct v4l2_subdev_pad_config *cfg,
+			     struct v4l2_subdev_format *sdformat)
+{
+	struct csi_state *state = mipi_sd_to_csi2_state(sd);
+	struct csi2_pix_format const *csi2_fmt;
+	struct v4l2_mbus_framefmt *fmt;
+
+	/*
+	 * The device can't transcode in any way, the source format can't be
+	 * modified.
+	 */
+	if (sdformat->pad == MIPI_CSI2_PAD_SOURCE)
+		return mipi_csi2_get_fmt(sd, cfg, sdformat);
+
+	if (sdformat->pad != MIPI_CSI2_PAD_SINK)
+		return -EINVAL;
+
+	csi2_fmt = find_csi2_format(sdformat->format.code);
+	if (!csi2_fmt) {
+		dev_err(state->dev, "no format found based on code %d\n",
+			sdformat->format.code);
+		csi2_fmt = &mipi_csi2_formats[0];
+	}
+
+	fmt = mipi_csi2_get_format(state, cfg, sdformat->which, sdformat->pad);
+
+	mutex_lock(&state->lock);
+
+	fmt->code = csi2_fmt->code;
+	fmt->width = sdformat->format.width;
+	fmt->height = sdformat->format.height;
+
+	sdformat->format = *fmt;
+
+	/* Propagate the format from sink to source. */
+	fmt = mipi_csi2_get_format(state, cfg, sdformat->which,
+				   MIPI_CSI2_PAD_SOURCE);
+	*fmt = sdformat->format;
+
+	/* Store the CSI2 format descriptor for active formats. */
+	if (sdformat->which == V4L2_SUBDEV_FORMAT_ACTIVE)
+		state->csi2_fmt = csi2_fmt;
+
+	mutex_unlock(&state->lock);
+
+	/* https://community.nxp.com/t5/i-MX-Processors/Explenation-for-HS-SETTLE-parameter-in-MIPI-CSI-D-PHY-registers/m-p/764275/highlight/true#M118744 */
+	if (sdformat->format.width * sdformat->format.height > 720 * 480)
+		state->hs_settle = 0x9;
+	else
+		state->hs_settle = 0x14;
+
+	state->send_level = 64;
+
+	dev_dbg(state->dev,
+		"%s: format %dx%d send_level %d hs_settle 0x%X\n", __func__,
+		sdformat->format.width, sdformat->format.height,
+		state->send_level, state->hs_settle);
+
+	return 0;
+}
+
+static int mipi_csi2_log_status(struct v4l2_subdev *sd)
+{
+	struct csi_state *state = mipi_sd_to_csi2_state(sd);
+
+	mutex_lock(&state->lock);
+	mutex_unlock(&state->lock);
+
+	return 0;
+}
+
+static const struct v4l2_subdev_core_ops mipi_csi2_core_ops = {
+	.log_status	= mipi_csi2_log_status,
+};
+
+static const struct v4l2_subdev_video_ops mipi_csi2_video_ops = {
+	.s_stream	= mipi_csi2_s_stream,
+};
+
+static const struct v4l2_subdev_pad_ops mipi_csi2_pad_ops = {
+	.init_cfg		= mipi_csi2_init_cfg,
+	.enum_mbus_code		= mipi_csi2_enum_mbus_code,
+	.get_fmt		= mipi_csi2_get_fmt,
+	.set_fmt		= mipi_csi2_set_fmt,
+};
+
+static const struct v4l2_subdev_ops mipi_csi2_subdev_ops = {
+	.core	= &mipi_csi2_core_ops,
+	.video	= &mipi_csi2_video_ops,
+	.pad	= &mipi_csi2_pad_ops,
+};
+
+/* -----------------------------------------------------------------------------
+ * Media entity operations
+ */
+
+static int mipi_csi2_link_setup(struct media_entity *entity,
+				const struct media_pad *local_pad,
+				const struct media_pad *remote_pad, u32 flags)
+{
+	struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
+	struct csi_state *state = mipi_sd_to_csi2_state(sd);
+	struct v4l2_subdev *remote_sd;
+
+	dev_dbg(state->dev, "link setup %s -> %s", remote_pad->entity->name,
+		local_pad->entity->name);
+
+	/* We only care about the link to the source. */
+	if (!(local_pad->flags & MEDIA_PAD_FL_SINK))
+		return 0;
+
+	remote_sd = media_entity_to_v4l2_subdev(remote_pad->entity);
+
+	if (flags & MEDIA_LNK_FL_ENABLED) {
+		if (state->src_sd)
+			return -EBUSY;
+
+		state->src_sd = remote_sd;
+	} else {
+		state->src_sd = NULL;
+	}
+
+	return 0;
+}
+
+static const struct media_entity_operations mipi_csi2_entity_ops = {
+	.link_setup	= mipi_csi2_link_setup,
+	.link_validate	= v4l2_subdev_link_validate,
+	.get_fwnode_pad = v4l2_subdev_get_fwnode_pad_1_to_1,
+};
+
+/* -----------------------------------------------------------------------------
+ * Async subdev notifier
+ */
+
+static struct csi_state *
+mipi_notifier_to_csi2_state(struct v4l2_async_notifier *n)
+{
+	return container_of(n, struct csi_state, notifier);
+}
+
+static int mipi_csi2_notify_bound(struct v4l2_async_notifier *notifier,
+				  struct v4l2_subdev *sd,
+				  struct v4l2_async_subdev *asd)
+{
+	struct csi_state *state = mipi_notifier_to_csi2_state(notifier);
+	struct media_pad *sink = &state->sd.entity.pads[MIPI_CSI2_PAD_SINK];
+
+	return v4l2_create_fwnode_links_to_pad(sd, sink, 0);
+}
+
+static const struct v4l2_async_notifier_operations mipi_csi2_notify_ops = {
+	.bound = mipi_csi2_notify_bound,
+};
+
+static int mipi_csi2_async_register(struct csi_state *state)
+{
+	struct v4l2_fwnode_endpoint vep = {
+		.bus_type = V4L2_MBUS_CSI2_DPHY,
+	};
+	struct v4l2_async_subdev *asd;
+	struct fwnode_handle *ep;
+	unsigned int i;
+	int ret;
+
+	v4l2_async_notifier_init(&state->notifier);
+
+	ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(state->dev), 0, 0,
+					     FWNODE_GRAPH_ENDPOINT_NEXT);
+	if (!ep)
+		return -ENOTCONN;
+
+	ret = v4l2_fwnode_endpoint_parse(ep, &vep);
+	if (ret)
+		goto err_parse;
+
+	for (i = 0; i < vep.bus.mipi_csi2.num_data_lanes; ++i) {
+		if (vep.bus.mipi_csi2.data_lanes[i] != i + 1) {
+			dev_err(state->dev,
+				"data lanes reordering is not supported");
+			goto err_parse;
+		}
+	}
+
+	state->bus = vep.bus.mipi_csi2;
+
+	dev_dbg(state->dev, "data lanes: %d\n", state->bus.num_data_lanes);
+	dev_dbg(state->dev, "flags: 0x%08x\n", state->bus.flags);
+
+	asd = v4l2_async_notifier_add_fwnode_remote_subdev(&state->notifier,
+							   ep, struct v4l2_async_subdev);
+	if (IS_ERR(asd)) {
+		ret = PTR_ERR(asd);
+		goto err_parse;
+	}
+
+	fwnode_handle_put(ep);
+
+	state->notifier.ops = &mipi_csi2_notify_ops;
+
+	ret = v4l2_async_subdev_notifier_register(&state->sd, &state->notifier);
+	if (ret)
+		return ret;
+
+	return v4l2_async_register_subdev(&state->sd);
+
+err_parse:
+	fwnode_handle_put(ep);
+
+	return ret;
+}
+
+/* -----------------------------------------------------------------------------
+ * Suspend/resume
+ */
+
+static int mipi_csi2_pm_suspend(struct device *dev, bool runtime)
+{
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
+	struct csi_state *state = mipi_sd_to_csi2_state(sd);
+	int ret = 0;
+
+	mutex_lock(&state->lock);
+	if (state->state & ST_POWERED) {
+		mipi_csi2_stop_stream(state);
+		mipi_csi2_clk_disable(state);
+		state->state &= ~ST_POWERED;
+		if (!runtime)
+			state->state |= ST_SUSPENDED;
+	}
+
+	mutex_unlock(&state->lock);
+
+	ret = icc_set_bw(state->icc_path, 0, 0);
+	if (ret)
+		dev_err(dev, "icc_set_bw failed with %d\n", ret);
+
+	return ret ? -EAGAIN : 0;
+}
+
+static int mipi_csi2_pm_resume(struct device *dev, bool runtime)
+{
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
+	struct csi_state *state = mipi_sd_to_csi2_state(sd);
+	int ret = 0;
+
+	ret = icc_set_bw(state->icc_path, 0, state->icc_path_bw);
+	if (ret) {
+		dev_err(dev, "icc_set_bw failed with %d\n", ret);
+		return ret;
+	}
+
+	mutex_lock(&state->lock);
+	if (!runtime && !(state->state & ST_SUSPENDED))
+		goto unlock;
+
+	if (!(state->state & ST_POWERED)) {
+		state->state |= ST_POWERED;
+		ret = mipi_csi2_clk_enable(state);
+	}
+	if (state->state & ST_STREAMING)
+		mipi_csi2_start_stream(state);
+
+	state->state &= ~ST_SUSPENDED;
+
+unlock:
+	mutex_unlock(&state->lock);
+
+	return ret ? -EAGAIN : 0;
+}
+
+static int __maybe_unused mipi_csi2_suspend(struct device *dev)
+{
+	return mipi_csi2_pm_suspend(dev, false);
+}
+
+static int __maybe_unused mipi_csi2_resume(struct device *dev)
+{
+	return mipi_csi2_pm_resume(dev, false);
+}
+
+static int __maybe_unused mipi_csi2_runtime_suspend(struct device *dev)
+{
+	return mipi_csi2_pm_suspend(dev, true);
+}
+
+static int __maybe_unused mipi_csi2_runtime_resume(struct device *dev)
+{
+	return mipi_csi2_pm_resume(dev, true);
+}
+
+static const struct dev_pm_ops mipi_csi2_pm_ops = {
+	SET_RUNTIME_PM_OPS(mipi_csi2_runtime_suspend, mipi_csi2_runtime_resume,
+			   NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(mipi_csi2_suspend, mipi_csi2_resume)
+};
+
+/* -----------------------------------------------------------------------------
+ * Probe/remove & platform driver
+ */
+
+static int mipi_csi2_subdev_init(struct csi_state *state)
+{
+	struct v4l2_subdev *sd = &state->sd;
+
+	v4l2_subdev_init(sd, &mipi_csi2_subdev_ops);
+	sd->owner = THIS_MODULE;
+	snprintf(sd->name, sizeof(sd->name), "%s.%d",
+		 MIPI_CSI2_SUBDEV_NAME, state->index);
+
+	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	sd->ctrl_handler = NULL;
+
+	sd->entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
+	sd->entity.ops = &mipi_csi2_entity_ops;
+
+	sd->dev = state->dev;
+
+	state->csi2_fmt = &mipi_csi2_formats[0];
+	mipi_csi2_init_cfg(sd, NULL);
+
+	state->pads[MIPI_CSI2_PAD_SINK].flags = MEDIA_PAD_FL_SINK
+					 | MEDIA_PAD_FL_MUST_CONNECT;
+	state->pads[MIPI_CSI2_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE
+					   | MEDIA_PAD_FL_MUST_CONNECT;
+	return media_entity_pads_init(&sd->entity, MIPI_CSI2_PADS_NUM,
+				      state->pads);
+}
+
+static int init_icc(struct platform_device *pdev)
+{
+	struct v4l2_subdev *sd = dev_get_drvdata(&pdev->dev);
+	struct csi_state *state = mipi_sd_to_csi2_state(sd);
+	int ret;
+
+	/* Optional interconnect request */
+	state->icc_path = of_icc_get(&pdev->dev, "dram");
+	if (IS_ERR(state->icc_path)) {
+		ret = PTR_ERR(state->icc_path);
+		if (ret == -EPROBE_DEFER)
+			return ret;
+
+		state->icc_path = NULL;
+		return 0;
+	}
+
+	state->icc_path_bw = MBps_to_icc(700);
+
+	ret = icc_set_bw(state->icc_path, 0, state->icc_path_bw);
+	if (ret) {
+		dev_err(&pdev->dev, "icc_set_bw failed with %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int mipi_csi2_parse_dt(struct csi_state *state)
+{
+	struct device_node *node = state->dev->of_node;
+	const u32 *addr;
+	int len;
+	int reg;
+
+	addr = of_get_property(node, "reg", &len);
+	if (!addr) {
+		dev_err(state->dev, "no reg property found\n");
+		return -EINVAL;
+	}
+
+	reg = be32_to_cpup(addr);
+
+	if ((reg >> 16) == MIPI_CSI2_RX_CSR_1_BASE_ADDR >> 16) {
+		state->phy_gpr_reg = MIPI_CSI2_RX_CSR_1_GPR_REG;
+		state->hw_reset_reg = MIPI_CSI2_RX_CSR_1_HW_RESET_REG;
+	} else if ((reg >> 16) == MIPI_CSI2_RX_CSR_2_BASE_ADDR >> 16) {
+		state->phy_gpr_reg = MIPI_CSI2_RX_CSR_2_GPR_REG;
+		state->hw_reset_reg = MIPI_CSI2_RX_CSR_2_HW_RESET_REG;
+	}
+
+	return 0;
+}
+
+static int mipi_csi2_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct csi_state *state;
+	int ret;
+
+	state = devm_kzalloc(dev, sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	mutex_init(&state->lock);
+
+	state->dev = dev;
+
+	ret = mipi_csi2_parse_dt(state);
+	if (ret < 0) {
+		dev_err(dev, "Failed to parse device tree: %d\n", ret);
+		return ret;
+	}
+
+	/* Acquire resources. */
+	state->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(state->regs))
+		return PTR_ERR(state->regs);
+
+	ret = mipi_csi2_clk_get(state);
+	if (ret < 0)
+		return ret;
+
+	/* Initialize and register the subdev. */
+	ret = mipi_csi2_subdev_init(state);
+	if (ret < 0)
+		goto disable_clock;
+
+	platform_set_drvdata(pdev, &state->sd);
+
+	ret = mipi_csi2_async_register(state);
+	if (ret < 0) {
+		dev_err(dev, "async register failed: %d\n", ret);
+		goto cleanup;
+	}
+
+	ret = init_icc(pdev);
+	if (ret)
+		goto cleanup;
+
+	/* Enable runtime PM. */
+	pm_runtime_enable(dev);
+	if (!pm_runtime_enabled(dev)) {
+		ret = mipi_csi2_pm_resume(dev, true);
+		if (ret < 0)
+			goto cleanup;
+	}
+
+	dev_info(dev, "lanes: %d\n", state->bus.num_data_lanes);
+
+	return 0;
+
+cleanup:
+	media_entity_cleanup(&state->sd.entity);
+	v4l2_async_notifier_unregister(&state->notifier);
+	v4l2_async_notifier_cleanup(&state->notifier);
+	v4l2_async_unregister_subdev(&state->sd);
+disable_clock:
+	mipi_csi2_clk_disable(state);
+	mutex_destroy(&state->lock);
+
+	return ret;
+}
+
+static int mipi_csi2_remove(struct platform_device *pdev)
+{
+	struct v4l2_subdev *sd = platform_get_drvdata(pdev);
+	struct csi_state *state = mipi_sd_to_csi2_state(sd);
+
+	v4l2_async_notifier_unregister(&state->notifier);
+	v4l2_async_notifier_cleanup(&state->notifier);
+	v4l2_async_unregister_subdev(&state->sd);
+
+	pm_runtime_disable(&pdev->dev);
+	mipi_csi2_pm_suspend(&pdev->dev, true);
+	mipi_csi2_clk_disable(state);
+	media_entity_cleanup(&state->sd.entity);
+	mutex_destroy(&state->lock);
+	pm_runtime_set_suspended(&pdev->dev);
+	icc_put(state->icc_path);
+
+	return 0;
+}
+
+static const struct of_device_id mipi_csi2_of_match[] = {
+	{ .compatible = "fsl,imx8mq-mipi-csi2",},
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, mipi_csi2_of_match);
+
+static struct platform_driver mipi_csi2_driver = {
+	.probe		= mipi_csi2_probe,
+	.remove		= mipi_csi2_remove,
+	.driver		= {
+		.of_match_table = mipi_csi2_of_match,
+		.name		= MIPI_CSI2_DRIVER_NAME,
+		.pm		= &mipi_csi2_pm_ops,
+	},
+};
+
+module_platform_driver(mipi_csi2_driver);
+
+MODULE_DESCRIPTION("i.MX8MQ MIPI CSI-2 receiver driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:imx8mq-mipi-csi2");
-- 
2.30.2