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From:   Prabhakar <prabhakar.csengg@gmail.com>
To:     Sakari Ailus <sakari.ailus@linux.intel.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Jacopo Mondi <jacopo@jmondi.org>,
        =?UTF-8?q?Niklas=20S=C3=B6derlund?= <niklas.soderlund@ragnatech.se>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc:     Geert Uytterhoeven <geert+renesas@glider.be>,
        linux-media@vger.kernel.org, devicetree@vger.kernel.org,
        linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org,
        Prabhakar <prabhakar.csengg@gmail.com>,
        Biju Das <biju.das.jz@bp.renesas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: [PATCH v4 3/4] media: platform: Add Renesas RZ/G2L MIPI CSI-2 receiver driver
Date:   Thu, 27 Oct 2022 11:31:03 +0100
Message-Id: <20221027103104.74576-4-prabhakar.mahadev-lad.rj@bp.renesas.com>
In-Reply-To: <20221027103104.74576-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
References: <20221027103104.74576-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
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From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Add MIPI CSI-2 receiver driver for Renesas RZ/G2L. The MIPI
CSI-2 is part of the CRU module found on RZ/G2L family.

Based on a patch in the BSP by Hien Huynh
<hien.huynh.px@renesas.com>

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
v3 -> v4
* Implemented post_streamoff callback

v2 -> v3
* Switched to runtime PM
* Implemented pre_streamon callback in CSI driver
* Got rid of rzg2l_csi2_cmn_rstb_deassert()/
  rzg2l_csi2_dphy_setting/rzg2l_csi2_mipi_link_setting() from CSI driver
* Switched to for-loop instead of if block for getting CSI timings
* Fixed rzg2l_csi2_set_format() as pointed by Laurent
* Copied all colorspace-related fields received from userspace (colorspace,
  xfer_func, ycbcr_enc and quantization) in rzg2l_csi2_set_format.
* Initialised pad in rzg2l_csi2_init_config() 
* Introduced RZG2L_CSI2_DEFAULT_WIDTH/HEIGHT/FMT macros
* Dropped RZG2L_CSI2_SOURCE_VC0-RZG2L_CSI2_SOURCE_VC3 macros

v1 -> v2
* Sorted Kconfig select
* Prefixed generic names for struct/variables with rzg2_csi2
* Dropped unnecessary checks for remote source
* Dropped exporting functions
* Moved lane validation to probe
* Split up rzg2l_csi2_dphy_setting() and rzg2l_csi2_mipi_link_setting()
* Used rzg2l_csi2_write() wherever possible
* Dropped stream_count/lock
* Used active subdev state instead of manually storing format in driver
* Implemented init_cfg/enum_frame_size/enum_mbus_code callbacks
* Dropped check for bus_type of remote source
* Switched to manually turn ON/OFF the clocks instead of pm_runtime so that
  the mipi/dhpy initialization happens as per the HW manual
* Hardcoded VC0 usage for now as streams API is under development

RFC v2 -> v1
* Fixed initialization sequence of DPHY and link
* Exported DPHY and link initialization functions so that the
  CRU core driver can initialize the CRU and CSI2 as per the HW manual.

RFC v1 -> RFC v2
* new patch (split up as new driver compared to v1)
---
 drivers/media/platform/renesas/Kconfig        |   1 +
 drivers/media/platform/renesas/Makefile       |   1 +
 .../media/platform/renesas/rzg2l-cru/Kconfig  |  17 +
 .../media/platform/renesas/rzg2l-cru/Makefile |   3 +
 .../platform/renesas/rzg2l-cru/rzg2l-csi2.c   | 869 ++++++++++++++++++
 5 files changed, 891 insertions(+)
 create mode 100644 drivers/media/platform/renesas/rzg2l-cru/Kconfig
 create mode 100644 drivers/media/platform/renesas/rzg2l-cru/Makefile
 create mode 100644 drivers/media/platform/renesas/rzg2l-cru/rzg2l-csi2.c

diff --git a/drivers/media/platform/renesas/Kconfig b/drivers/media/platform/renesas/Kconfig
index 9fd90672ea2d..ed788e991f74 100644
--- a/drivers/media/platform/renesas/Kconfig
+++ b/drivers/media/platform/renesas/Kconfig
@@ -41,6 +41,7 @@ config VIDEO_SH_VOU
 	  Support for the Video Output Unit (VOU) on SuperH SoCs.
 
 source "drivers/media/platform/renesas/rcar-vin/Kconfig"
+source "drivers/media/platform/renesas/rzg2l-cru/Kconfig"
 
 # Mem2mem drivers
 
diff --git a/drivers/media/platform/renesas/Makefile b/drivers/media/platform/renesas/Makefile
index 3ec226ef5fd2..55854e868887 100644
--- a/drivers/media/platform/renesas/Makefile
+++ b/drivers/media/platform/renesas/Makefile
@@ -4,6 +4,7 @@
 #
 
 obj-y += rcar-vin/
+obj-y += rzg2l-cru/
 obj-y += vsp1/
 
 obj-$(CONFIG_VIDEO_RCAR_DRIF) += rcar_drif.o
diff --git a/drivers/media/platform/renesas/rzg2l-cru/Kconfig b/drivers/media/platform/renesas/rzg2l-cru/Kconfig
new file mode 100644
index 000000000000..57c40bb499df
--- /dev/null
+++ b/drivers/media/platform/renesas/rzg2l-cru/Kconfig
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config VIDEO_RZG2L_CSI2
+	tristate "RZ/G2L MIPI CSI-2 Receiver"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	depends on V4L_PLATFORM_DRIVERS
+	depends on VIDEO_DEV && OF
+	select MEDIA_CONTROLLER
+	select RESET_CONTROLLER
+	select V4L2_FWNODE
+	select VIDEO_V4L2_SUBDEV_API
+	help
+	  Support for Renesas RZ/G2L (and alike SoC's) MIPI CSI-2
+	  Receiver driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rzg2l-csi2.
diff --git a/drivers/media/platform/renesas/rzg2l-cru/Makefile b/drivers/media/platform/renesas/rzg2l-cru/Makefile
new file mode 100644
index 000000000000..91ea97a944e6
--- /dev/null
+++ b/drivers/media/platform/renesas/rzg2l-cru/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_VIDEO_RZG2L_CSI2) += rzg2l-csi2.o
diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-csi2.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-csi2.c
new file mode 100644
index 000000000000..5997ce8994f9
--- /dev/null
+++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-csi2.c
@@ -0,0 +1,869 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for Renesas RZ/G2L MIPI CSI-2 Receiver
+ *
+ * Copyright (C) 2022 Renesas Electronics Corp.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+#include <linux/sys_soc.h>
+#include <linux/units.h>
+
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-fwnode.h>
+#include <media/v4l2-mc.h>
+#include <media/v4l2-subdev.h>
+
+/* LINK registers */
+/* Module Configuration Register */
+#define CSI2nMCG			0x0
+#define CSI2nMCG_SDLN			GENMASK(11, 8)
+
+/* Module Control Register 0 */
+#define CSI2nMCT0			0x10
+#define CSI2nMCT0_VDLN(x)		((x) << 0)
+
+/* Module Control Register 2 */
+#define CSI2nMCT2			0x18
+#define CSI2nMCT2_FRRSKW(x)		((x) << 16)
+#define CSI2nMCT2_FRRCLK(x)		((x) << 0)
+
+/* Module Control Register 3 */
+#define CSI2nMCT3			0x1c
+#define CSI2nMCT3_RXEN			BIT(0)
+
+/* Reset Control Register */
+#define CSI2nRTCT			0x28
+#define CSI2nRTCT_VSRST			BIT(0)
+
+/* Reset Status Register */
+#define CSI2nRTST			0x2c
+#define CSI2nRTST_VSRSTS		BIT(0)
+
+/* Receive Data Type Enable Low Register */
+#define CSI2nDTEL			0x60
+
+/* Receive Data Type Enable High Register */
+#define CSI2nDTEH			0x64
+
+/* DPHY registers */
+/* D-PHY Control Register 0 */
+#define CSIDPHYCTRL0			0x400
+#define CSIDPHYCTRL0_EN_LDO1200		BIT(1)
+#define CSIDPHYCTRL0_EN_BGR		BIT(0)
+
+/* D-PHY Timing Register 0 */
+#define CSIDPHYTIM0			0x404
+#define CSIDPHYTIM0_TCLK_MISS(x)	((x) << 24)
+#define CSIDPHYTIM0_T_INIT(x)		((x) << 0)
+
+/* D-PHY Timing Register 1 */
+#define CSIDPHYTIM1			0x408
+#define CSIDPHYTIM1_THS_PREPARE(x)	((x) << 24)
+#define CSIDPHYTIM1_TCLK_PREPARE(x)	((x) << 16)
+#define CSIDPHYTIM1_THS_SETTLE(x)	((x) << 8)
+#define CSIDPHYTIM1_TCLK_SETTLE(x)	((x) << 0)
+
+/* D-PHY Skew Adjustment Function */
+#define CSIDPHYSKW0			0x460
+#define CSIDPHYSKW0_UTIL_DL0_SKW_ADJ(x)	((x) & 0x3)
+#define CSIDPHYSKW0_UTIL_DL1_SKW_ADJ(x)	(((x) & 0x3) << 4)
+#define CSIDPHYSKW0_UTIL_DL2_SKW_ADJ(x)	(((x) & 0x3) << 8)
+#define CSIDPHYSKW0_UTIL_DL3_SKW_ADJ(x)	(((x) & 0x3) << 12)
+#define CSIDPHYSKW0_DEFAULT_SKW		CSIDPHYSKW0_UTIL_DL0_SKW_ADJ(1) | \
+					CSIDPHYSKW0_UTIL_DL1_SKW_ADJ(1) | \
+					CSIDPHYSKW0_UTIL_DL2_SKW_ADJ(1) | \
+					CSIDPHYSKW0_UTIL_DL3_SKW_ADJ(1)
+
+#define VSRSTS_RETRIES			20
+
+#define RZG2L_CSI2_MIN_WIDTH		320
+#define RZG2L_CSI2_MIN_HEIGHT		240
+#define RZG2L_CSI2_MAX_WIDTH		2800
+#define RZG2L_CSI2_MAX_HEIGHT		4095
+
+#define RZG2L_CSI2_DEFAULT_WIDTH	RZG2L_CSI2_MIN_WIDTH
+#define RZG2L_CSI2_DEFAULT_HEIGHT	RZG2L_CSI2_MIN_HEIGHT
+#define RZG2L_CSI2_DEFAULT_FMT		MEDIA_BUS_FMT_UYVY8_1X16
+
+enum rzg2l_csi2_pads {
+	RZG2L_CSI2_SINK = 0,
+	RZG2L_CSI2_SOURCE,
+	NR_OF_RZG2L_CSI2_PAD,
+};
+
+struct rzg2l_csi2 {
+	struct device *dev;
+	void __iomem *base;
+	struct reset_control *presetn;
+	struct reset_control *cmn_rstb;
+	struct clk *sysclk;
+	unsigned long vclk_rate;
+
+	struct v4l2_subdev subdev;
+	struct media_pad pads[NR_OF_RZG2L_CSI2_PAD];
+
+	struct v4l2_async_notifier notifier;
+	struct v4l2_subdev *remote_source;
+
+	unsigned short lanes;
+	unsigned long hsfreq;
+
+	bool dphy_enabled;
+};
+
+struct rzg2l_csi2_timings {
+	u32 t_init;
+	u32 tclk_miss;
+	u32 tclk_settle;
+	u32 ths_settle;
+	u32 tclk_prepare;
+	u32 ths_prepare;
+	u32 max_hsfreq;
+};
+
+static const struct rzg2l_csi2_timings rzg2l_csi2_global_timings[] = {
+	[0] = {
+		.max_hsfreq = 80,
+		.t_init = 79801,
+		.tclk_miss = 4,
+		.tclk_settle = 23,
+		.ths_settle = 31,
+		.tclk_prepare = 10,
+		.ths_prepare = 19,
+	},
+	[1] = {
+		.max_hsfreq = 125,
+		.t_init = 79801,
+		.tclk_miss = 4,
+		.tclk_settle = 23,
+		.ths_settle = 28,
+		.tclk_prepare = 10,
+		.ths_prepare = 19,
+	},
+	[2] = {
+		.max_hsfreq = 250,
+		.t_init = 79801,
+		.tclk_miss = 4,
+		.tclk_settle = 23,
+		.ths_settle = 22,
+		.tclk_prepare = 10,
+		.ths_prepare = 16,
+	},
+	[3] = {
+		.max_hsfreq = 360,
+		.t_init = 79801,
+		.tclk_miss = 4,
+		.tclk_settle = 18,
+		.ths_settle = 19,
+		.tclk_prepare = 10,
+		.ths_prepare = 10,
+	},
+	[4] = {
+		.max_hsfreq = 1500,
+		.t_init = 79801,
+		.tclk_miss = 4,
+		.tclk_settle = 18,
+		.ths_settle = 18,
+		.tclk_prepare = 10,
+		.ths_prepare = 10,
+	},
+};
+
+struct rzg2l_csi2_format {
+	u32 code;
+	unsigned int datatype;
+	unsigned int bpp;
+};
+
+static const struct rzg2l_csi2_format rzg2l_csi2_formats[] = {
+	{ .code = MEDIA_BUS_FMT_UYVY8_1X16,	.datatype = 0x1e, .bpp = 16 },
+};
+
+static inline struct rzg2l_csi2 *sd_to_csi2(struct v4l2_subdev *sd)
+{
+	return container_of(sd, struct rzg2l_csi2, subdev);
+}
+
+static const struct rzg2l_csi2_format *rzg2l_csi2_code_to_fmt(unsigned int code)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(rzg2l_csi2_formats); i++)
+		if (rzg2l_csi2_formats[i].code == code)
+			return &rzg2l_csi2_formats[i];
+
+	return NULL;
+}
+
+static inline struct rzg2l_csi2 *notifier_to_csi2(struct v4l2_async_notifier *n)
+{
+	return container_of(n, struct rzg2l_csi2, notifier);
+}
+
+static u32 rzg2l_csi2_read(struct rzg2l_csi2 *csi2, unsigned int reg)
+{
+	return ioread32(csi2->base + reg);
+}
+
+static void rzg2l_csi2_write(struct rzg2l_csi2 *csi2, unsigned int reg,
+			     u32 data)
+{
+	iowrite32(data, csi2->base + reg);
+}
+
+static void rzg2l_csi2_set(struct rzg2l_csi2 *csi2, unsigned int reg, u32 set)
+{
+	rzg2l_csi2_write(csi2, reg, rzg2l_csi2_read(csi2, reg) | set);
+}
+
+static void rzg2l_csi2_clr(struct rzg2l_csi2 *csi2, unsigned int reg, u32 clr)
+{
+	rzg2l_csi2_write(csi2, reg, rzg2l_csi2_read(csi2, reg) & ~clr);
+}
+
+static int rzg2l_csi2_calc_mbps(struct rzg2l_csi2 *csi2)
+{
+	struct v4l2_subdev *source = csi2->remote_source;
+	const struct rzg2l_csi2_format *format;
+	const struct v4l2_mbus_framefmt *fmt;
+	struct v4l2_subdev_state *state;
+	struct v4l2_ctrl *ctrl;
+	u64 mbps;
+
+	/* Read the pixel rate control from remote. */
+	ctrl = v4l2_ctrl_find(source->ctrl_handler, V4L2_CID_PIXEL_RATE);
+	if (!ctrl) {
+		dev_err(csi2->dev, "no pixel rate control in subdev %s\n",
+			source->name);
+		return -EINVAL;
+	}
+
+	state = v4l2_subdev_lock_and_get_active_state(&csi2->subdev);
+	fmt = v4l2_subdev_get_pad_format(&csi2->subdev, state, RZG2L_CSI2_SINK);
+	format = rzg2l_csi2_code_to_fmt(fmt->code);
+	v4l2_subdev_unlock_state(state);
+
+	/*
+	 * Calculate hsfreq in Mbps
+	 * hsfreq = (pixel_rate * bits_per_sample) / number_of_lanes
+	 */
+	mbps = v4l2_ctrl_g_ctrl_int64(ctrl) * format->bpp;
+	do_div(mbps, csi2->lanes * 1000000);
+
+	return mbps;
+}
+
+/* -----------------------------------------------------------------------------
+ * DPHY setting
+ */
+
+static int rzg2l_csi2_dphy_disable(struct rzg2l_csi2 *csi2)
+{
+	int ret;
+
+	/* Reset the CRU (D-PHY) */
+	ret = reset_control_assert(csi2->cmn_rstb);
+	if (ret)
+		return ret;
+
+	/* Stop the D-PHY clock */
+	clk_disable_unprepare(csi2->sysclk);
+
+	/* Cancel the EN_LDO1200 register setting */
+	rzg2l_csi2_clr(csi2, CSIDPHYCTRL0, CSIDPHYCTRL0_EN_LDO1200);
+
+	/* Cancel the EN_BGR register setting */
+	rzg2l_csi2_clr(csi2, CSIDPHYCTRL0, CSIDPHYCTRL0_EN_BGR);
+
+	csi2->dphy_enabled = false;
+
+	return 0;
+}
+
+static int rzg2l_csi2_dphy_enable(struct rzg2l_csi2 *csi2)
+{
+	const struct rzg2l_csi2_timings *dphy_timing;
+	u32 dphytim0, dphytim1;
+	unsigned int i;
+	int mbps;
+	int ret;
+
+	mbps = rzg2l_csi2_calc_mbps(csi2);
+	if (mbps < 0)
+		return mbps;
+
+	csi2->hsfreq = mbps;
+
+	/* Set DPHY timing parameters */
+	for (i = 0; i < ARRAY_SIZE(rzg2l_csi2_global_timings); ++i) {
+		dphy_timing = &rzg2l_csi2_global_timings[i];
+
+		if (csi2->hsfreq <= dphy_timing->max_hsfreq)
+			break;
+	}
+
+	if (i >= ARRAY_SIZE(rzg2l_csi2_global_timings))
+		return -EINVAL;
+
+	/* Set D-PHY timing parameters */
+	dphytim0 = CSIDPHYTIM0_TCLK_MISS(dphy_timing->tclk_miss) |
+			CSIDPHYTIM0_T_INIT(dphy_timing->t_init);
+	dphytim1 = CSIDPHYTIM1_THS_PREPARE(dphy_timing->ths_prepare) |
+			CSIDPHYTIM1_TCLK_PREPARE(dphy_timing->tclk_prepare) |
+			CSIDPHYTIM1_THS_SETTLE(dphy_timing->ths_settle) |
+			CSIDPHYTIM1_TCLK_SETTLE(dphy_timing->tclk_settle);
+	rzg2l_csi2_write(csi2, CSIDPHYTIM0, dphytim0);
+	rzg2l_csi2_write(csi2, CSIDPHYTIM1, dphytim1);
+
+	/* Enable D-PHY power control 0 */
+	rzg2l_csi2_write(csi2, CSIDPHYSKW0, CSIDPHYSKW0_DEFAULT_SKW);
+
+	/* Set the EN_BGR bit */
+	rzg2l_csi2_set(csi2, CSIDPHYCTRL0, CSIDPHYCTRL0_EN_BGR);
+
+	/* Delay 20us to be stable */
+	usleep_range(20, 40);
+
+	/* Enable D-PHY power control 1 */
+	rzg2l_csi2_set(csi2, CSIDPHYCTRL0, CSIDPHYCTRL0_EN_LDO1200);
+
+	/* Delay 10us to be stable */
+	usleep_range(10, 20);
+
+	/* Start supplying the internal clock for the D-PHY block */
+	ret = clk_prepare_enable(csi2->sysclk);
+	if (ret)
+		rzg2l_csi2_dphy_disable(csi2);
+
+	csi2->dphy_enabled = true;
+
+	return ret;
+}
+
+static int rzg2l_csi2_enable_reg_access(struct rzg2l_csi2 *csi2)
+{
+	int ret;
+
+	ret = reset_control_deassert(csi2->presetn);
+	if (ret < 0)
+		return ret;
+
+	ret = pm_runtime_resume_and_get(csi2->dev);
+	if (ret)
+		reset_control_assert(csi2->presetn);
+
+	return ret;
+}
+
+static void rzg2l_csi2_disable_reg_access(struct rzg2l_csi2 *csi2)
+{
+	pm_runtime_put_sync(csi2->dev);
+	reset_control_assert(csi2->presetn);
+}
+
+static int rzg2l_csi2_dphy_setting(struct v4l2_subdev *sd, bool on)
+{
+	struct rzg2l_csi2 *csi2 = sd_to_csi2(sd);
+	int ret;
+
+	ret = rzg2l_csi2_enable_reg_access(csi2);
+	if (ret < 0)
+		return ret;
+
+	if (on)
+		ret = rzg2l_csi2_dphy_enable(csi2);
+	else
+		ret = rzg2l_csi2_dphy_disable(csi2);
+
+	rzg2l_csi2_disable_reg_access(csi2);
+
+	return ret;
+}
+
+static void rzg2l_csi2_mipi_link_enable(struct rzg2l_csi2 *csi2)
+{
+	unsigned long vclk_rate = csi2->vclk_rate / HZ_PER_MHZ;
+	u32 frrskw, frrclk, frrskw_coeff, frrclk_coeff;
+
+	/* Select data lanes */
+	rzg2l_csi2_write(csi2, CSI2nMCT0, CSI2nMCT0_VDLN(csi2->lanes));
+
+	frrskw_coeff = 3 * vclk_rate * 8;
+	frrclk_coeff = frrskw_coeff / 2;
+	frrskw = DIV_ROUND_UP(frrskw_coeff, csi2->hsfreq);
+	frrclk = DIV_ROUND_UP(frrclk_coeff, csi2->hsfreq);
+	rzg2l_csi2_write(csi2, CSI2nMCT2, CSI2nMCT2_FRRSKW(frrskw) |
+			 CSI2nMCT2_FRRCLK(frrclk));
+
+	/*
+	 * Select data type.
+	 * FS, FE, LS, LE, Generic Short Packet Codes 1 to 8,
+	 * Generic Long Packet Data Types 1 to 4 YUV422 8-bit,
+	 * RGB565, RGB888, RAW8 to RAW20, User-defined 8-bit
+	 * data types 1 to 8
+	 */
+	rzg2l_csi2_write(csi2, CSI2nDTEL, 0xf778ff0f);
+	rzg2l_csi2_write(csi2, CSI2nDTEH, 0x00ffff1f);
+
+	/* Enable LINK reception */
+	rzg2l_csi2_write(csi2, CSI2nMCT3, CSI2nMCT3_RXEN);
+}
+
+static void rzg2l_csi2_mipi_link_disable(struct rzg2l_csi2 *csi2)
+{
+	unsigned int timeout = VSRSTS_RETRIES;
+
+	/* Stop LINK reception */
+	rzg2l_csi2_clr(csi2, CSI2nMCT3, CSI2nMCT3_RXEN);
+
+	/* Request a software reset of the LINK Video Pixel Interface */
+	rzg2l_csi2_write(csi2, CSI2nRTCT, CSI2nRTCT_VSRST);
+
+	/* Make sure CSI2nRTST.VSRSTS bit is cleared */
+	while (timeout--) {
+		if (!(rzg2l_csi2_read(csi2, CSI2nRTST) & CSI2nRTST_VSRSTS))
+			break;
+		usleep_range(100, 200);
+	};
+
+	if (!timeout)
+		dev_err(csi2->dev, "Clearing CSI2nRTST.VSRSTS timed out\n");
+}
+
+static int rzg2l_csi2_mipi_link_setting(struct v4l2_subdev *sd, bool on)
+{
+	struct rzg2l_csi2 *csi2 = sd_to_csi2(sd);
+	int ret;
+
+	ret = rzg2l_csi2_enable_reg_access(csi2);
+	if (ret < 0)
+		return ret;
+
+	if (on)
+		rzg2l_csi2_mipi_link_enable(csi2);
+	else
+		rzg2l_csi2_mipi_link_disable(csi2);
+
+	rzg2l_csi2_disable_reg_access(csi2);
+
+	return 0;
+}
+
+static int rzg2l_csi2_s_stream(struct v4l2_subdev *sd, int enable)
+{
+	struct rzg2l_csi2 *csi2 = sd_to_csi2(sd);
+	int ret;
+
+	if (enable) {
+		int ret;
+
+		ret = rzg2l_csi2_mipi_link_setting(sd, 1);
+		if (ret)
+			return ret;
+
+		ret = reset_control_deassert(csi2->cmn_rstb);
+		if (ret)
+			return ret;
+	}
+
+	ret = v4l2_subdev_call(csi2->remote_source, video, s_stream, enable);
+	if (ret)
+		dev_err(csi2->dev, "s_stream failed on remote source\n");
+
+	if (!enable) {
+		ret |= rzg2l_csi2_dphy_setting(sd, 0);
+		ret |= rzg2l_csi2_mipi_link_setting(sd, 0);
+	}
+
+	return ret;
+}
+
+static int rzg2l_csi2_pre_streamon(struct v4l2_subdev *sd, u32 flags)
+{
+	return rzg2l_csi2_dphy_setting(sd, 1);
+}
+
+static int rzg2l_csi2_post_streamoff(struct v4l2_subdev *sd)
+{
+	struct rzg2l_csi2 *csi2 = sd_to_csi2(sd);
+
+	/*
+	 * In ideal case D-PHY will be disabled in s_stream(0) callback
+	 * as mentioned the HW manual. The below will only happen when
+	 * pre_streamon succeeds and further down the line s_stream(1)
+	 * fails so we need to undo things in post_streamoff.
+	 */
+	if (csi2->dphy_enabled)
+		return rzg2l_csi2_dphy_setting(sd, 0);
+
+	return 0;
+}
+
+static int rzg2l_csi2_set_format(struct v4l2_subdev *sd,
+				 struct v4l2_subdev_state *state,
+				 struct v4l2_subdev_format *fmt)
+{
+	struct v4l2_mbus_framefmt *src_format;
+	struct v4l2_mbus_framefmt *sink_format;
+
+	if (fmt->pad != RZG2L_CSI2_SINK && fmt->pad != RZG2L_CSI2_SOURCE)
+		return -EINVAL;
+
+	sink_format = v4l2_subdev_get_pad_format(sd, state, RZG2L_CSI2_SINK);
+	src_format = v4l2_subdev_get_pad_format(sd, state, RZG2L_CSI2_SOURCE);
+
+	if (!rzg2l_csi2_code_to_fmt(fmt->format.code))
+		sink_format->code = rzg2l_csi2_formats[0].code;
+	else
+		sink_format->code = fmt->format.code;
+
+	sink_format->field = V4L2_FIELD_NONE;
+	sink_format->colorspace = fmt->format.colorspace;
+	sink_format->xfer_func = fmt->format.xfer_func;
+	sink_format->ycbcr_enc = fmt->format.ycbcr_enc;
+	sink_format->quantization = fmt->format.quantization;
+	sink_format->width = clamp_t(u32, fmt->format.width,
+				     RZG2L_CSI2_MIN_WIDTH, RZG2L_CSI2_MAX_WIDTH);
+	sink_format->height = clamp_t(u32, fmt->format.height,
+				      RZG2L_CSI2_MIN_HEIGHT, RZG2L_CSI2_MAX_HEIGHT);
+	fmt->format = *sink_format;
+
+	/* propagate format to source pad */
+	*src_format = *sink_format;
+
+	return 0;
+}
+
+static int rzg2l_csi2_init_config(struct v4l2_subdev *sd,
+				  struct v4l2_subdev_state *sd_state)
+{
+	struct v4l2_subdev_format fmt = { .pad = RZG2L_CSI2_SINK, };
+
+	fmt.format.width = RZG2L_CSI2_DEFAULT_WIDTH;
+	fmt.format.height = RZG2L_CSI2_DEFAULT_HEIGHT;
+	fmt.format.field = V4L2_FIELD_NONE;
+	fmt.format.code = RZG2L_CSI2_DEFAULT_FMT;
+	fmt.format.colorspace = V4L2_COLORSPACE_SRGB;
+	fmt.format.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
+	fmt.format.quantization = V4L2_QUANTIZATION_DEFAULT;
+	fmt.format.xfer_func = V4L2_XFER_FUNC_DEFAULT;
+
+	return rzg2l_csi2_set_format(sd, sd_state, &fmt);
+}
+
+static int rzg2l_csi2_enum_mbus_code(struct v4l2_subdev *sd,
+				     struct v4l2_subdev_state *sd_state,
+				     struct v4l2_subdev_mbus_code_enum *code)
+{
+	if (code->index >= ARRAY_SIZE(rzg2l_csi2_formats))
+		return -EINVAL;
+
+	code->code = rzg2l_csi2_formats[code->index].code;
+
+	return 0;
+}
+
+static int rzg2l_csi2_enum_frame_size(struct v4l2_subdev *sd,
+				      struct v4l2_subdev_state *sd_state,
+				      struct v4l2_subdev_frame_size_enum *fse)
+{
+	if (fse->index != 0)
+		return -EINVAL;
+
+	fse->min_width = RZG2L_CSI2_MIN_WIDTH;
+	fse->min_height = RZG2L_CSI2_MIN_HEIGHT;
+	fse->max_width = RZG2L_CSI2_MAX_WIDTH;
+	fse->max_height = RZG2L_CSI2_MAX_HEIGHT;
+
+	return 0;
+}
+
+static const struct v4l2_subdev_video_ops rzg2l_csi2_video_ops = {
+	.s_stream = rzg2l_csi2_s_stream,
+	.pre_streamon = rzg2l_csi2_pre_streamon,
+	.post_streamoff = rzg2l_csi2_post_streamoff,
+};
+
+static const struct v4l2_subdev_pad_ops rzg2l_csi2_pad_ops = {
+	.enum_mbus_code = rzg2l_csi2_enum_mbus_code,
+	.init_cfg = rzg2l_csi2_init_config,
+	.enum_frame_size = rzg2l_csi2_enum_frame_size,
+	.set_fmt = rzg2l_csi2_set_format,
+	.get_fmt = v4l2_subdev_get_fmt,
+};
+
+static const struct v4l2_subdev_ops rzg2l_csi2_subdev_ops = {
+	.video	= &rzg2l_csi2_video_ops,
+	.pad	= &rzg2l_csi2_pad_ops,
+};
+
+/* -----------------------------------------------------------------------------
+ * Async handling and registration of subdevices and links.
+ */
+
+static int rzg2l_csi2_notify_bound(struct v4l2_async_notifier *notifier,
+				   struct v4l2_subdev *subdev,
+				   struct v4l2_async_subdev *asd)
+{
+	struct rzg2l_csi2 *csi2 = notifier_to_csi2(notifier);
+
+	csi2->remote_source = subdev;
+
+	dev_dbg(csi2->dev, "Bound subdev: %s pad\n", subdev->name);
+
+	return media_create_pad_link(&subdev->entity, RZG2L_CSI2_SINK,
+				     &csi2->subdev.entity, 0,
+				     MEDIA_LNK_FL_ENABLED |
+				     MEDIA_LNK_FL_IMMUTABLE);
+}
+
+static void rzg2l_csi2_notify_unbind(struct v4l2_async_notifier *notifier,
+				     struct v4l2_subdev *subdev,
+				     struct v4l2_async_subdev *asd)
+{
+	struct rzg2l_csi2 *csi2 = notifier_to_csi2(notifier);
+
+	csi2->remote_source = NULL;
+
+	dev_dbg(csi2->dev, "Unbind subdev %s\n", subdev->name);
+}
+
+static const struct v4l2_async_notifier_operations rzg2l_csi2_notify_ops = {
+	.bound = rzg2l_csi2_notify_bound,
+	.unbind = rzg2l_csi2_notify_unbind,
+};
+
+static int rzg2l_csi2_parse_v4l2(struct rzg2l_csi2 *csi2,
+				 struct v4l2_fwnode_endpoint *vep)
+{
+	/* Only port 0 endpoint 0 is valid. */
+	if (vep->base.port || vep->base.id)
+		return -ENOTCONN;
+
+	csi2->lanes = vep->bus.mipi_csi2.num_data_lanes;
+
+	return 0;
+}
+
+static int rzg2l_csi2_parse_dt(struct rzg2l_csi2 *csi2)
+{
+	struct v4l2_fwnode_endpoint v4l2_ep = {
+		.bus_type = V4L2_MBUS_CSI2_DPHY
+	};
+	struct v4l2_async_subdev *asd;
+	struct fwnode_handle *fwnode;
+	struct fwnode_handle *ep;
+	int ret;
+
+	ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(csi2->dev), 0, 0, 0);
+	if (!ep) {
+		dev_err(csi2->dev, "Not connected to subdevice\n");
+		return -EINVAL;
+	}
+
+	ret = v4l2_fwnode_endpoint_parse(ep, &v4l2_ep);
+	if (ret) {
+		dev_err(csi2->dev, "Could not parse v4l2 endpoint\n");
+		fwnode_handle_put(ep);
+		return -EINVAL;
+	}
+
+	ret = rzg2l_csi2_parse_v4l2(csi2, &v4l2_ep);
+	if (ret) {
+		fwnode_handle_put(ep);
+		return ret;
+	}
+
+	fwnode = fwnode_graph_get_remote_endpoint(ep);
+	fwnode_handle_put(ep);
+
+	v4l2_async_nf_init(&csi2->notifier);
+	csi2->notifier.ops = &rzg2l_csi2_notify_ops;
+
+	asd = v4l2_async_nf_add_fwnode(&csi2->notifier, fwnode,
+				       struct v4l2_async_subdev);
+	fwnode_handle_put(fwnode);
+	if (IS_ERR(asd))
+		return PTR_ERR(asd);
+
+	ret = v4l2_async_subdev_nf_register(&csi2->subdev, &csi2->notifier);
+	if (ret)
+		v4l2_async_nf_cleanup(&csi2->notifier);
+
+	return ret;
+}
+
+static int rzg2l_validate_csi2_lanes(struct rzg2l_csi2 *csi2)
+{
+	int ret = 0;
+	int lanes;
+
+	if (csi2->lanes != 1 && csi2->lanes != 2 && csi2->lanes != 4) {
+		dev_err(csi2->dev, "Unsupported number of data-lanes: %u\n",
+			csi2->lanes);
+		return -EINVAL;
+	}
+
+	ret = rzg2l_csi2_enable_reg_access(csi2);
+	if (ret < 0)
+		return ret;
+
+	/* Checking the maximum lanes support for CSI-2 module */
+	lanes = (rzg2l_csi2_read(csi2, CSI2nMCG) & CSI2nMCG_SDLN) >> 8;
+	if (lanes < csi2->lanes) {
+		dev_err(csi2->dev,
+			"Failed to support %d data lanes\n", csi2->lanes);
+		ret = -EINVAL;
+	}
+
+	rzg2l_csi2_disable_reg_access(csi2);
+
+	return ret;
+}
+
+/* -----------------------------------------------------------------------------
+ * Platform Device Driver.
+ */
+
+static const struct media_entity_operations rzg2l_csi2_entity_ops = {
+	.link_validate = v4l2_subdev_link_validate,
+};
+
+static int rzg2l_csi2_probe(struct platform_device *pdev)
+{
+	struct rzg2l_csi2 *csi2;
+	struct clk *vclk;
+	int ret;
+
+	csi2 = devm_kzalloc(&pdev->dev, sizeof(*csi2), GFP_KERNEL);
+	if (!csi2)
+		return -ENOMEM;
+
+	csi2->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(csi2->base))
+		return PTR_ERR(csi2->base);
+
+	csi2->cmn_rstb = devm_reset_control_get_exclusive(&pdev->dev, "cmn-rstb");
+	if (IS_ERR(csi2->cmn_rstb))
+		return dev_err_probe(&pdev->dev, PTR_ERR(csi2->cmn_rstb),
+				     "Failed to get cpg cmn-rstb\n");
+
+	csi2->presetn = devm_reset_control_get_shared(&pdev->dev, "presetn");
+	if (IS_ERR(csi2->presetn))
+		return dev_err_probe(&pdev->dev, PTR_ERR(csi2->presetn),
+				     "Failed to get cpg presetn\n");
+
+	csi2->sysclk = devm_clk_get(&pdev->dev, "system");
+	if (IS_ERR(csi2->sysclk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(csi2->sysclk),
+				     "Failed to get system clk\n");
+
+	vclk = clk_get(&pdev->dev, "video");
+	if (IS_ERR(vclk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(vclk),
+				     "Failed to get video clock\n");
+	csi2->vclk_rate = clk_get_rate(vclk);
+	clk_put(vclk);
+
+	csi2->dev = &pdev->dev;
+
+	platform_set_drvdata(pdev, csi2);
+
+	ret = rzg2l_csi2_parse_dt(csi2);
+	if (ret)
+		return ret;
+
+	pm_runtime_enable(&pdev->dev);
+
+	ret = rzg2l_validate_csi2_lanes(csi2);
+	if (ret)
+		goto error_pm;
+
+	csi2->subdev.dev = &pdev->dev;
+	v4l2_subdev_init(&csi2->subdev, &rzg2l_csi2_subdev_ops);
+	v4l2_set_subdevdata(&csi2->subdev, &pdev->dev);
+	snprintf(csi2->subdev.name, sizeof(csi2->subdev.name),
+		 "csi-%s", dev_name(&pdev->dev));
+	csi2->subdev.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
+
+	csi2->subdev.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
+	csi2->subdev.entity.ops = &rzg2l_csi2_entity_ops;
+
+	csi2->pads[RZG2L_CSI2_SINK].flags = MEDIA_PAD_FL_SINK;
+	/*
+	 * TODO: RZ/G2L CSI2 supports 4 virtual channels, as virtual
+	 * channels should be implemented by streams API which is under
+	 * development lets hardcode to VC0 for now.
+	 */
+	csi2->pads[RZG2L_CSI2_SOURCE].flags = MEDIA_PAD_FL_SOURCE;
+	ret = media_entity_pads_init(&csi2->subdev.entity, 2, csi2->pads);
+	if (ret)
+		goto error_pm;
+
+	ret = v4l2_subdev_init_finalize(&csi2->subdev);
+	if (ret < 0)
+		goto error_async;
+
+	ret = v4l2_async_register_subdev(&csi2->subdev);
+	if (ret < 0)
+		goto error_subdev;
+
+	return 0;
+
+error_subdev:
+	v4l2_subdev_cleanup(&csi2->subdev);
+error_async:
+	v4l2_async_nf_unregister(&csi2->notifier);
+	v4l2_async_nf_cleanup(&csi2->notifier);
+	media_entity_cleanup(&csi2->subdev.entity);
+error_pm:
+	pm_runtime_disable(&pdev->dev);
+
+	return ret;
+}
+
+static int rzg2l_csi2_remove(struct platform_device *pdev)
+{
+	struct rzg2l_csi2 *csi2 = platform_get_drvdata(pdev);
+
+	v4l2_async_nf_unregister(&csi2->notifier);
+	v4l2_async_nf_cleanup(&csi2->notifier);
+	v4l2_async_unregister_subdev(&csi2->subdev);
+	v4l2_subdev_cleanup(&csi2->subdev);
+	media_entity_cleanup(&csi2->subdev.entity);
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+static const struct of_device_id rzg2l_csi2_of_table[] = {
+	{ .compatible = "renesas,rzg2l-csi2", },
+	{ /* sentinel */ }
+};
+
+static struct platform_driver rzg2l_csi2_pdrv = {
+	.remove	= rzg2l_csi2_remove,
+	.probe	= rzg2l_csi2_probe,
+	.driver	= {
+		.name = "rzg2l-csi2",
+		.of_match_table = rzg2l_csi2_of_table,
+	},
+};
+
+module_platform_driver(rzg2l_csi2_pdrv);
+
+MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>");
+MODULE_DESCRIPTION("Renesas RZ/G2L MIPI CSI2 receiver driver");
+MODULE_LICENSE("GPL");
-- 
2.25.1