Re: [PATCH v12 4/8] media: platform: visconti: Add Toshiba Visconti CSI-2 Receiver driver

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hello Ishikawa-san,

Thank you for the patch.

On Mon, Nov 25, 2024 at 06:21:42PM +0900, Yuji Ishikawa wrote:
> Add support to MIPI CSI-2 Receiver on Toshiba Visconti ARM SoCs.
> This driver is used with Visconti Video Input Interface driver.
> 
> Signed-off-by: Yuji Ishikawa <yuji2.ishikawa@toshiba.co.jp>
> ---
> Changelog v12:
> - Separate CSI2RX driver and made it independent driver
> - viif_csi2rx subdevice driver (in v11 patch) was removed.
> - dictionary order at Kconfig and Makefile
> 
>  drivers/media/platform/Kconfig                |   1 +
>  drivers/media/platform/Makefile               |   1 +
>  drivers/media/platform/toshiba/Kconfig        |   6 +
>  drivers/media/platform/toshiba/Makefile       |   2 +
>  .../media/platform/toshiba/visconti/Kconfig   |  16 +
>  .../media/platform/toshiba/visconti/Makefile  |   8 +
>  .../platform/toshiba/visconti/csi2rx_drv.c    | 791 ++++++++++++++++++
>  7 files changed, 825 insertions(+)
>  create mode 100644 drivers/media/platform/toshiba/Kconfig
>  create mode 100644 drivers/media/platform/toshiba/Makefile
>  create mode 100644 drivers/media/platform/toshiba/visconti/Kconfig
>  create mode 100644 drivers/media/platform/toshiba/visconti/Makefile
>  create mode 100644 drivers/media/platform/toshiba/visconti/csi2rx_drv.c
> 
> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> index 85d2627776b6..761b15b07b90 100644
> --- a/drivers/media/platform/Kconfig
> +++ b/drivers/media/platform/Kconfig
> @@ -86,6 +86,7 @@ source "drivers/media/platform/samsung/Kconfig"
>  source "drivers/media/platform/st/Kconfig"
>  source "drivers/media/platform/sunxi/Kconfig"
>  source "drivers/media/platform/ti/Kconfig"
> +source "drivers/media/platform/toshiba/Kconfig"
>  source "drivers/media/platform/verisilicon/Kconfig"
>  source "drivers/media/platform/via/Kconfig"
>  source "drivers/media/platform/xilinx/Kconfig"
> diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
> index ace4e34483dd..917145fe5171 100644
> --- a/drivers/media/platform/Makefile
> +++ b/drivers/media/platform/Makefile
> @@ -29,6 +29,7 @@ obj-y += samsung/
>  obj-y += st/
>  obj-y += sunxi/
>  obj-y += ti/
> +obj-y += toshiba/
>  obj-y += verisilicon/
>  obj-y += via/
>  obj-y += xilinx/
> diff --git a/drivers/media/platform/toshiba/Kconfig b/drivers/media/platform/toshiba/Kconfig
> new file mode 100644
> index 000000000000..f02983f4fc97
> --- /dev/null
> +++ b/drivers/media/platform/toshiba/Kconfig
> @@ -0,0 +1,6 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +comment "Toshiba media platform drivers"
> +
> +source "drivers/media/platform/toshiba/visconti/Kconfig"
> +
> diff --git a/drivers/media/platform/toshiba/Makefile b/drivers/media/platform/toshiba/Makefile
> new file mode 100644
> index 000000000000..2bce85ef3b48
> --- /dev/null
> +++ b/drivers/media/platform/toshiba/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only

A blank line would be nice here.

> +obj-y += visconti/
> diff --git a/drivers/media/platform/toshiba/visconti/Kconfig b/drivers/media/platform/toshiba/visconti/Kconfig
> new file mode 100644
> index 000000000000..e5c92d598f8b
> --- /dev/null
> +++ b/drivers/media/platform/toshiba/visconti/Kconfig
> @@ -0,0 +1,16 @@
> +# SPDX-License-Identifier: GPL-2.0-only

A blank line would be nice here too.

> +config VIDEO_VISCONTI_CSI2RX
> +	tristate "Visconti MIPI CSI-2 Receiver driver"
> +	depends on V4L_PLATFORM_DRIVERS
> +	depends on VIDEO_DEV && OF
> +	depends on ARCH_VISCONTI || COMPILE_TEST
> +	select MEDIA_CONTROLLER
> +	select VIDEO_V4L2_SUBDEV_API
> +	select V4L2_FWNODE
> +	help
> +	  Support for Toshiba Visconti MIPI CSI-2 receiver,
> +	  which is used with Visconti Camera Interface driver.
> +
> +	  This driver yields 1 subdevice node for a hardware instance.
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called visconti-csi2rx.
> diff --git a/drivers/media/platform/toshiba/visconti/Makefile b/drivers/media/platform/toshiba/visconti/Makefile
> new file mode 100644
> index 000000000000..62a029376134
> --- /dev/null
> +++ b/drivers/media/platform/toshiba/visconti/Makefile
> @@ -0,0 +1,8 @@
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Makefile for the Visconti video input device driver
> +#
> +
> +visconti-csi2rx-objs = csi2rx_drv.o
> +
> +obj-$(CONFIG_VIDEO_VISCONTI_CSI2RX) += visconti-csi2rx.o
> diff --git a/drivers/media/platform/toshiba/visconti/csi2rx_drv.c b/drivers/media/platform/toshiba/visconti/csi2rx_drv.c
> new file mode 100644
> index 000000000000..94567963872a
> --- /dev/null
> +++ b/drivers/media/platform/toshiba/visconti/csi2rx_drv.c
> @@ -0,0 +1,791 @@
> +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
> +/* Toshiba Visconti Video Capture Support

/*
 * Toshiba Visconti Video Capture Support
 *

> + *
> + * (C) Copyright 2024 TOSHIBA CORPORATION
> + * (C) Copyright 2024 Toshiba Electronic Devices & Storage Corporation
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_graph.h>

You don't need those two headers. You however need to include

- linux/device.h (for devm_kzalloc)
- linux/property.h (for the fwnode_* API)

> +#include <linux/platform_device.h>
> +
> +#include <media/mipi-csi2.h>
> +#include <media/v4l2-common.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-fwnode.h>
> +#include <media/v4l2-subdev.h>
> +
> +/* CSI2HOST register space */
> +#define REG_CSI2RX_NLANES	 0x4
> +#define REG_CSI2RX_RESETN	 0x8
> +#define REG_CSI2RX_INT_ST_MAIN	 0xc
> +#define REG_CSI2RX_DATA_IDS_1	 0x10
> +#define REG_CSI2RX_DATA_IDS_2	 0x14
> +#define REG_CSI2RX_PHY_SHUTDOWNZ 0x40
> +#define REG_CSI2RX_PHY_RSTZ	 0x44
> +
> +/* access to dphy external registers */

/* Access to dphy external registers */

Same in other comments below.

> +#define REG_CSI2RX_PHY_TESTCTRL0 0x50
> +#define BIT_TESTCTRL0_CLK_0	 0
> +#define BIT_TESTCTRL0_CLK_1	 BIT(1)
> +
> +#define REG_CSI2RX_PHY_TESTCTRL1 0x54
> +#define BIT_TESTCTRL1_ADDR	 BIT(16)
> +#define MASK_TESTCTRL1_DIN	 0xff
> +#define MASK_TESTCTRL1_DOUT	 0xff00
> +
> +#define REG_CSI2RX_INT_ST_PHY_FATAL  0xe0
> +#define REG_CSI2RX_INT_MSK_PHY_FATAL 0xe4
> +#define MASK_PHY_FATAL_ALL	     0x0000000f
> +
> +#define REG_CSI2RX_INT_ST_PKT_FATAL  0xf0
> +#define REG_CSI2RX_INT_MSK_PKT_FATAL 0xf4
> +#define MASK_PKT_FATAL_ALL	     0x0001000f
> +
> +#define REG_CSI2RX_INT_ST_FRAME_FATAL  0x100
> +#define REG_CSI2RX_INT_MSK_FRAME_FATAL 0x104
> +#define MASK_FRAME_FATAL_ALL	       0x000f0f0f
> +
> +#define REG_CSI2RX_INT_ST_PHY  0x110
> +#define REG_CSI2RX_INT_MSK_PHY 0x114
> +#define MASK_PHY_ERROR_ALL     0x000f000f
> +
> +#define REG_CSI2RX_INT_ST_PKT  0x120
> +#define REG_CSI2RX_INT_MSK_PKT 0x124
> +#define MASK_PKT_ERROR_ALL     0x000f000f
> +
> +#define REG_CSI2RX_INT_ST_LINE	0x130
> +#define REG_CSI2RX_INT_MSK_LINE 0x134
> +#define MASK_LINE_ERROR_ALL	0x00ff00ff
> +
> +/* DPHY register space */
> +enum dphy_testcode {
> +	DIG_TESTCODE_EXT = 0,
> +	DIG_SYS_0 = 0x001,
> +	DIG_SYS_1 = 0x002,
> +	DIG_SYS_3 = 0x004,
> +	DIG_SYS_7 = 0x008,
> +	DIG_RX_STARTUP_OVR_2 = 0x0e2,
> +	DIG_RX_STARTUP_OVR_3 = 0x0e3,
> +	DIG_RX_STARTUP_OVR_4 = 0x0e4,
> +	DIG_RX_STARTUP_OVR_5 = 0x0e5,
> +	DIG_CB_2 = 0x1ac,
> +	DIG_TERM_CAL_0 = 0x220,
> +	DIG_TERM_CAL_1 = 0x221,
> +	DIG_TERM_CAL_2 = 0x222,
> +	DIG_CLKLANE_LANE_6 = 0x307,
> +	DIG_CLKLANE_OFFSET_CAL_0 = 0x39d,
> +	DIG_LANE0_OFFSET_CAL_0 = 0x59f,
> +	DIG_LANE0_DDL_0 = 0x5e0,
> +	DIG_LANE1_OFFSET_CAL_0 = 0x79f,
> +	DIG_LANE1_DDL_0 = 0x7e0,
> +	DIG_LANE2_OFFSET_CAL_0 = 0x99f,
> +	DIG_LANE2_DDL_0 = 0x9e0,
> +	DIG_LANE3_OFFSET_CAL_0 = 0xb9f,
> +	DIG_LANE3_DDL_0 = 0xbe0,
> +};
> +
> +#define SYS_0_HSFREQRANGE_OVR  BIT(5)
> +#define SYS_3_NO_REXT	       BIT(4)
> +#define SYS_7_RESERVED	       FIELD_PREP(0x1f, 0x0c)
> +#define SYS_7_DESKEW_POL       BIT(5)
> +#define STARTUP_OVR_4_CNTVAL   FIELD_PREP(0x70, 0x01)
> +#define STARTUP_OVR_4_DDL_EN   BIT(0)
> +#define STARTUP_OVR_5_BYPASS   BIT(0)
> +#define CB_2_LPRX_BIAS	       BIT(6)
> +#define CB_2_RESERVED	       FIELD_PREP(0x3f, 0x0b)
> +#define CLKLANE_RXHS_PULL_LONG BIT(7)
> +
> +/* bit mask for calibration result registers */
> +#define MASK_TERM_CAL_ERR  0
> +#define MASK_TERM_CAL_DONE BIT(7)
> +#define MASK_CLK_CAL_ERR   BIT(4)
> +#define MASK_CLK_CAL_DONE  BIT(0)
> +#define MASK_CAL_ERR	   BIT(2)
> +#define MASK_CAL_DONE	   BIT(1)
> +#define MASK_DDL_ERR	   BIT(1)
> +#define MASK_DDL_DONE	   BIT(2)
> +
> +#define VISCONTI_CSI2RX_ERROR_MONITORS_NUM 8
> +
> +/**
> + * struct visconti_csi2rx_line_err_target
> + *
> + * Virtual Channel and Data Type pair for CSI2RX line error monitor
> + *
> + * When 0 is set to dt, line error detection is disabled.
> + *
> + * @vc: Virtual Channel to monitor; Range 0..3
> + * @dt: Data Type to monitor; Range 0, 0x10..0x3f
> + */
> +struct visconti_csi2rx_line_err_target {
> +	u32 vc[VISCONTI_CSI2RX_ERROR_MONITORS_NUM];
> +	u32 dt[VISCONTI_CSI2RX_ERROR_MONITORS_NUM];
> +};
> +
> +#define CSI2RX_MIN_DATA_RATE 80U
> +#define CSI2RX_MAX_DATA_RATE 1500U
> +
> +#define VISCONTI_CSI2RX_PAD_SINK 0
> +#define VISCONTI_CSI2RX_PAD_SRC	 1
> +#define VISCONTI_CSI2RX_PAD_NUM	 2
> +
> +#define VISCONTI_CSI2RX_DEF_WIDTH  1920
> +#define VISCONTI_CSI2RX_DEF_HEIGHT 1080
> +#define VISCONTI_CSI2RX_MIN_WIDTH  640
> +#define VISCONTI_CSI2RX_MAX_WIDTH  3840
> +#define VISCONTI_CSI2RX_MIN_HEIGHT 480
> +#define VISCONTI_CSI2RX_MAX_HEIGHT 2160
> +
> +struct visconti_csi2rx {
> +	struct device *dev;
> +	void __iomem *base;
> +
> +	struct v4l2_subdev subdev;
> +	struct media_pad pads[VISCONTI_CSI2RX_PAD_NUM];
> +	struct v4l2_async_notifier notifier;
> +	struct v4l2_subdev *remote;
> +	unsigned int remote_pad;
> +
> +	unsigned int lanes;
> +
> +	unsigned int irq;
> +};
> +
> +static inline struct visconti_csi2rx *notifier_to_csi2(struct v4l2_async_notifier *n)
> +{
> +	return container_of(n, struct visconti_csi2rx, notifier);
> +}
> +
> +static inline struct visconti_csi2rx *sd_to_csi2(struct v4l2_subdev *sd)
> +{
> +	return container_of(sd, struct visconti_csi2rx, subdev);
> +}
> +
> +static inline void visconti_csi2rx_write(struct visconti_csi2rx *priv, u32 regid, u32 val)

The media subsystem tries to limit line lengths to 80 columns, when it
doesn't hinder readability. For instance here you could write

static inline void visconti_csi2rx_write(struct visconti_csi2rx *priv,
					 u32 regid, u32 val)

If lines are just a few characters over 80 columns the need to break
them is less than if they approach 100 columns. It's a "soft limit"
policy to try and maximize readability.

> +{
> +	writel(val, priv->base + regid);
> +}
> +
> +static inline u32 visconti_csi2rx_read(struct visconti_csi2rx *priv, u32 regid)
> +{
> +	return readl(priv->base + regid);
> +}
> +
> +static inline void tick_testclk(struct visconti_csi2rx *priv)

Don't inline this or the next function, compilers are smart enough to
decide by themselves these days.

> +{
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL0, BIT_TESTCTRL0_CLK_1);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL0, BIT_TESTCTRL0_CLK_0);
> +}
> +
> +static inline void set_dphy_addr(struct visconti_csi2rx *priv, u32 test_mode)
> +{
> +	/* select testcode Ex space with top 4bits of test_mode */
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL1,
> +			      BIT_TESTCTRL1_ADDR | DIG_TESTCODE_EXT);
> +	tick_testclk(priv);

If writing to REG_CSI2RX_PHY_TESTCTRL1 always needs to be followed by a
call to tick_testclk(), I would create a visconti_csi2rx_dphy_write()
function:

static void visconti_csi2rx_dphy_write(struct visconti_csi2rx *priv, u32 data)
{
	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL1, data);
	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL0, BIT_TESTCTRL0_CLK_1);
	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL0, BIT_TESTCTRL0_CLK_0);
}

> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL1, FIELD_GET(0xf00, test_mode));

And here

	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL1,
			      FIELD_GET(0xf00, test_mode));

There are many other places below that go over 80 columns.

> +	tick_testclk(priv);
> +
> +	/* set bottom 8bit of test_mode */
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL1,
> +			      BIT_TESTCTRL1_ADDR | FIELD_GET(0xff, test_mode));
> +	tick_testclk(priv);
> +}
> +
> +static void write_dphy_param(struct visconti_csi2rx *priv, u32 test_mode, u8 test_in)
> +{
> +	set_dphy_addr(priv, test_mode);
> +
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL1, (u32)test_in);

Is the (u8) explicit cast needed ?

> +	tick_testclk(priv);
> +}
> +
> +struct csi2rx_dphy_hs_info {
> +	u32 rate;
> +	u32 hsfreqrange;
> +	u32 osc_freq_target;
> +};
> +
> +static const struct csi2rx_dphy_hs_info dphy_hs_info[] = {
> +	{ 80, 0x0, 0x1cc },   { 85, 0x10, 0x1cc },   { 95, 0x20, 0x1cc },   { 105, 0x30, 0x1cc },
> +	{ 115, 0x1, 0x1cc },  { 125, 0x11, 0x1cc },  { 135, 0x21, 0x1cc },  { 145, 0x31, 0x1cc },
> +	{ 155, 0x2, 0x1cc },  { 165, 0x12, 0x1cc },  { 175, 0x22, 0x1cc },  { 185, 0x32, 0x1cc },
> +	{ 198, 0x3, 0x1cc },  { 213, 0x13, 0x1cc },  { 228, 0x23, 0x1cc },  { 243, 0x33, 0x1cc },
> +	{ 263, 0x4, 0x1cc },  { 288, 0x14, 0x1cc },  { 313, 0x25, 0x1cc },  { 338, 0x35, 0x1cc },
> +	{ 375, 0x5, 0x1cc },  { 425, 0x16, 0x1cc },  { 475, 0x26, 0x1cc },  { 525, 0x37, 0x1cc },
> +	{ 575, 0x7, 0x1cc },  { 625, 0x18, 0x1cc },  { 675, 0x28, 0x1cc },  { 725, 0x39, 0x1cc },
> +	{ 775, 0x9, 0x1cc },  { 825, 0x19, 0x1cc },  { 875, 0x29, 0x1cc },  { 925, 0x3a, 0x1cc },
> +	{ 975, 0xa, 0x1cc },  { 1025, 0x1a, 0x1cc }, { 1075, 0x2a, 0x1cc }, { 1125, 0x3b, 0x1cc },
> +	{ 1175, 0xb, 0x1cc }, { 1225, 0x1b, 0x1cc }, { 1275, 0x2b, 0x1cc }, { 1325, 0x3c, 0x1cc },
> +	{ 1375, 0xc, 0x1cc }, { 1425, 0x1c, 0x1cc }, { 1475, 0x2c, 0x1cc }

osc_freq_target seems to always be 0x1cc, does it have to be stored in
this table ?

> +};
> +
> +static void get_dphy_hs_transfer_info(u32 dphy_rate, u32 *hsfreqrange, u32 *osc_freq_target)
> +{
> +	unsigned int i;
> +
> +	for (i = 1; i < ARRAY_SIZE(dphy_hs_info); i++) {
> +		if (dphy_rate < dphy_hs_info[i].rate) {
> +			*hsfreqrange = dphy_hs_info[i - 1].hsfreqrange;
> +			*osc_freq_target = dphy_hs_info[i - 1].osc_freq_target;
> +			return;
> +		}
> +	}
> +
> +	/* not found; return the largest entry */
> +	*hsfreqrange = dphy_hs_info[ARRAY_SIZE(dphy_hs_info) - 1].hsfreqrange;
> +	*osc_freq_target = dphy_hs_info[ARRAY_SIZE(dphy_hs_info) - 1].osc_freq_target;
> +}
> +
> +static void visconti_csi2rx_set_dphy_rate(struct visconti_csi2rx *priv, u32 dphy_rate)
> +{
> +	u32 hsfreqrange, osc_freq_target;
> +
> +	get_dphy_hs_transfer_info(dphy_rate, &hsfreqrange, &osc_freq_target);
> +
> +	write_dphy_param(priv, DIG_SYS_1, (u8)hsfreqrange);

I don't think the explicit cast is needed here either.

> +	write_dphy_param(priv, DIG_SYS_0, SYS_0_HSFREQRANGE_OVR);
> +	write_dphy_param(priv, DIG_RX_STARTUP_OVR_5, STARTUP_OVR_5_BYPASS);
> +	write_dphy_param(priv, DIG_RX_STARTUP_OVR_4, STARTUP_OVR_4_CNTVAL);
> +	write_dphy_param(priv, DIG_CB_2, CB_2_LPRX_BIAS | CB_2_RESERVED);
> +	write_dphy_param(priv, DIG_SYS_7, SYS_7_DESKEW_POL | SYS_7_RESERVED);
> +	write_dphy_param(priv, DIG_CLKLANE_LANE_6, CLKLANE_RXHS_PULL_LONG);
> +	write_dphy_param(priv, DIG_RX_STARTUP_OVR_2, FIELD_GET(0xff, osc_freq_target));
> +	write_dphy_param(priv, DIG_RX_STARTUP_OVR_3, FIELD_GET(0xf00, osc_freq_target));
> +	write_dphy_param(priv, DIG_RX_STARTUP_OVR_4, STARTUP_OVR_4_CNTVAL | STARTUP_OVR_4_DDL_EN);
> +}
> +
> +static int visconti_csi2rx_initialize(struct visconti_csi2rx *priv, u32 num_lane, u32 dphy_rate,
> +				      const struct visconti_csi2rx_line_err_target *err_target)
> +{
> +	u32 val;
> +
> +	if (dphy_rate < CSI2RX_MIN_DATA_RATE || dphy_rate > CSI2RX_MAX_DATA_RATE) {
> +		dev_err(priv->dev, "Unsupported PHY speed (%u Mbps)", dphy_rate);
> +		return -ERANGE;
> +	}
> +
> +	/* 1st phase of initialization */
> +	visconti_csi2rx_write(priv, REG_CSI2RX_RESETN, 1);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_RSTZ, 0);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_SHUTDOWNZ, 0);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL0, 1);
> +	ndelay(15U);

I don't mind much, but the U suffix here and in many other places seems
unneeded.

> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL0, 0);
> +
> +	/* Configure D-PHY frequency range */
> +	visconti_csi2rx_set_dphy_rate(priv, dphy_rate);
> +
> +	/* 2nd phase of initialization */
> +	visconti_csi2rx_write(priv, REG_CSI2RX_NLANES, (num_lane - 1U));

No need for the inner parentheses.

> +	ndelay(5U);
> +
> +	/* Release D-PHY from Reset */
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_SHUTDOWNZ, 1);
> +	ndelay(5U);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_RSTZ, 1);
> +
> +	/* configuration of line error target */
> +	val = (err_target->vc[3] << 30U) | (err_target->dt[3] << 24U) | (err_target->vc[2] << 22U) |
> +	      (err_target->dt[2] << 16U) | (err_target->vc[1] << 14U) | (err_target->dt[1] << 8U) |
> +	      (err_target->vc[0] << 6U) | (err_target->dt[0]);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_DATA_IDS_1, val);
> +	val = (err_target->vc[7] << 30U) | (err_target->dt[7] << 24U) | (err_target->vc[6] << 22U) |
> +	      (err_target->dt[6] << 16U) | (err_target->vc[5] << 14U) | (err_target->dt[5] << 8U) |
> +	      (err_target->vc[4] << 6U) | (err_target->dt[4]);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_DATA_IDS_2, val);
> +
> +	/* configuration of mask */
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_PHY_FATAL, MASK_PHY_FATAL_ALL);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_PKT_FATAL, MASK_PKT_FATAL_ALL);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_FRAME_FATAL, MASK_FRAME_FATAL_ALL);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_PHY, MASK_PHY_ERROR_ALL);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_PKT, MASK_PKT_ERROR_ALL);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_LINE, MASK_LINE_ERROR_ALL);
> +
> +	return 0;
> +}
> +
> +struct visconti_csi2rx_format {
> +	u32 code;
> +	unsigned int bpp;
> +};
> +
> +static const struct visconti_csi2rx_format visconti_csi2rx_formats[] = {
> +	{ .code = MEDIA_BUS_FMT_RGB888_1X24, .bpp = 24 },
> +	{ .code = MEDIA_BUS_FMT_UYVY8_1X16, .bpp = 16 },
> +	{ .code = MEDIA_BUS_FMT_UYVY10_1X20, .bpp = 20 },
> +	{ .code = MEDIA_BUS_FMT_RGB565_1X16, .bpp = 16 },
> +	{ .code = MEDIA_BUS_FMT_SBGGR8_1X8, .bpp = 8 },
> +	{ .code = MEDIA_BUS_FMT_SGBRG8_1X8, .bpp = 8 },
> +	{ .code = MEDIA_BUS_FMT_SGRBG8_1X8, .bpp = 8 },
> +	{ .code = MEDIA_BUS_FMT_SRGGB8_1X8, .bpp = 8 },
> +	{ .code = MEDIA_BUS_FMT_SBGGR10_1X10, .bpp = 10 },
> +	{ .code = MEDIA_BUS_FMT_SGBRG10_1X10, .bpp = 10 },
> +	{ .code = MEDIA_BUS_FMT_SGRBG10_1X10, .bpp = 10 },
> +	{ .code = MEDIA_BUS_FMT_SRGGB10_1X10, .bpp = 10 },
> +	{ .code = MEDIA_BUS_FMT_SBGGR12_1X12, .bpp = 12 },
> +	{ .code = MEDIA_BUS_FMT_SGBRG12_1X12, .bpp = 12 },
> +	{ .code = MEDIA_BUS_FMT_SGRBG12_1X12, .bpp = 12 },
> +	{ .code = MEDIA_BUS_FMT_SRGGB12_1X12, .bpp = 12 },
> +	{ .code = MEDIA_BUS_FMT_SBGGR14_1X14, .bpp = 14 },
> +	{ .code = MEDIA_BUS_FMT_SGBRG14_1X14, .bpp = 14 },
> +	{ .code = MEDIA_BUS_FMT_SGRBG14_1X14, .bpp = 14 },
> +	{ .code = MEDIA_BUS_FMT_SRGGB14_1X14, .bpp = 14 },
> +};
> +
> +static const struct visconti_csi2rx_format *fmt_for_mbus_code(unsigned int mbus_code)
> +{
> +	int i;

unsigned int

> +
> +	for (i = 0; ARRAY_SIZE(visconti_csi2rx_formats); i++)
> +		if (visconti_csi2rx_formats[i].code == mbus_code)
> +			return &visconti_csi2rx_formats[i];

Please use curly braces for the 'for' statement.

No return when the look doesn't find a match ?

> +}
> +
> +static unsigned int bpp_for_mbus_code(unsigned int mbus_code)
> +{
> +	const struct visconti_csi2rx_format *fmt = fmt_for_mbus_code(mbus_code);
> +
> +	return fmt ? fmt->bpp : 0;
> +}
> +
> +static int64_t get_pixelclock(struct v4l2_subdev *sd)
> +{
> +	struct v4l2_ctrl *ctrl;
> +
> +	ctrl = v4l2_ctrl_find(sd->ctrl_handler, V4L2_CID_PIXEL_RATE);
> +	if (!ctrl)
> +		return -EINVAL;
> +
> +	return v4l2_ctrl_g_ctrl_int64(ctrl);
> +}
> +
> +static const struct visconti_csi2rx_line_err_target err_target_vc0_alldt = {
> +	/* select VC=0 */
> +	/* select all supported DataTypes */
> +	.dt = {
> +		MIPI_CSI2_DT_RGB565,
> +		MIPI_CSI2_DT_YUV422_8B,
> +		MIPI_CSI2_DT_YUV422_10B,
> +		MIPI_CSI2_DT_RGB888,
> +		MIPI_CSI2_DT_RAW8,
> +		MIPI_CSI2_DT_RAW10,
> +		MIPI_CSI2_DT_RAW12,
> +		MIPI_CSI2_DT_RAW14,
> +	}
> +};
> +
> +static int visconti_csi2rx_start(struct visconti_csi2rx *priv, struct v4l2_subdev_state *state)
> +{
> +	struct v4l2_mbus_framefmt *sink_fmt;

const

> +	int cur_bpp, dphy_rate;
> +	s64 pixelclock;
> +
> +	/* get bpp for current format */
> +	sink_fmt = v4l2_subdev_state_get_format(state, VISCONTI_CSI2RX_PAD_SINK);
> +	cur_bpp = bpp_for_mbus_code(sink_fmt->code);

	bpp = fmt_for_mbus_code(sink_fmt->code)->bpp;

and drop the bpp_for_mbus_code() function.

> +
> +	/* get pixel clock */
> +	pixelclock = get_pixelclock(priv->remote);

Use v4l2_get_link_freq() and drop the get_pixelclock() function.

> +	if (pixelclock < 0)
> +		return -EINVAL;
> +
> +	dphy_rate = div64_u64((u64)pixelclock * (u32)cur_bpp, priv->lanes * 1000000);
> +
> +	ndelay(15U);
> +
> +	return visconti_csi2rx_initialize(priv, priv->lanes, dphy_rate, &err_target_vc0_alldt);
> +}
> +
> +static void visconti_csi2rx_stop(struct visconti_csi2rx *priv)
> +{
> +	/* disable interrupt -> make sure registers cleared -> wait for current handlers finish */
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_PHY_FATAL, 0);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_PKT_FATAL, 0);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_FRAME_FATAL, 0);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_PHY, 0);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_PKT, 0);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_INT_MSK_LINE, 0);
> +	visconti_csi2rx_read(priv, REG_CSI2RX_INT_MSK_PHY_FATAL);
> +	visconti_csi2rx_read(priv, REG_CSI2RX_INT_MSK_PKT_FATAL);
> +	visconti_csi2rx_read(priv, REG_CSI2RX_INT_MSK_FRAME_FATAL);
> +	visconti_csi2rx_read(priv, REG_CSI2RX_INT_MSK_PHY);
> +	visconti_csi2rx_read(priv, REG_CSI2RX_INT_MSK_PKT);
> +	visconti_csi2rx_read(priv, REG_CSI2RX_INT_MSK_LINE);
> +	synchronize_irq(priv->irq);
> +
> +	/* shutdown hardware */
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_SHUTDOWNZ, 0);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_RSTZ, 0);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_PHY_TESTCTRL0, 1);
> +	visconti_csi2rx_write(priv, REG_CSI2RX_RESETN, 0);
> +}
> +
> +static int visconti_csi2rx_enable_streams(struct v4l2_subdev *sd, struct v4l2_subdev_state *state,
> +					  u32 pad, u64 streams_mask)
> +{
> +	struct visconti_csi2rx *priv = sd_to_csi2(sd);
> +	struct v4l2_subdev *remote_sd;
> +	struct media_pad *remote_pad;
> +	int ret;
> +
> +	remote_pad = media_pad_remote_pad_first(&sd->entity.pads[VISCONTI_CSI2RX_PAD_SINK]);
> +	if (!remote_pad)
> +		return -ENODEV;

Can't you use priv->remote and priv->remote_pad in this function instead
of getting the remote pad dynamically ? Same in
visconti_csi2rx_disable_streams().

> +	remote_sd = media_entity_to_v4l2_subdev(remote_pad->entity);
> +
> +	/* enabling: turn on CSI2RX -> turn on sensor */
> +	ret = visconti_csi2rx_start(priv, state);
> +	if (ret)
> +		return ret;
> +
> +	/* currently CSI2RX supports only stream0 in source pad */
> +	ret = v4l2_subdev_enable_streams(remote_sd, remote_pad->index, BIT(0));
> +	if (ret) {
> +		visconti_csi2rx_stop(priv);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int visconti_csi2rx_disable_streams(struct v4l2_subdev *sd, struct v4l2_subdev_state *state,
> +					   u32 pad, u64 streams_mask)
> +{
> +	struct visconti_csi2rx *priv = sd_to_csi2(sd);
> +	struct v4l2_subdev *remote_sd;
> +	struct media_pad *remote_pad;
> +
> +	remote_pad = media_pad_remote_pad_first(&sd->entity.pads[VISCONTI_CSI2RX_PAD_SINK]);
> +	if (!remote_pad)
> +		return -ENODEV;
> +	remote_sd = media_entity_to_v4l2_subdev(remote_pad->entity);
> +
> +	/* disabling: turn off sensor -> turn off CSI2RX */
> +	v4l2_subdev_disable_streams(remote_sd, remote_pad->index, BIT(0));
> +	visconti_csi2rx_stop(priv);
> +
> +	return 0;
> +}
> +
> +static int visconti_csi2rx_enum_mbus_code(struct v4l2_subdev *sd,
> +					  struct v4l2_subdev_state *sd_state,
> +					  struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	if (code->pad == VISCONTI_CSI2RX_PAD_SRC) {
> +		const struct v4l2_mbus_framefmt *sink_fmt;
> +
> +		/* SRC pad supports exactly the same format as SINK pad */
> +		if (code->index)
> +			return -EINVAL;
> +		sink_fmt = v4l2_subdev_state_get_format(sd_state, VISCONTI_CSI2RX_PAD_SINK);
> +		code->code = sink_fmt->code;
> +		return 0;
> +	}
> +
> +	if (code->index >= ARRAY_SIZE(visconti_csi2rx_formats))
> +		return -EINVAL;
> +	code->code = visconti_csi2rx_formats[code->index].code;
> +
> +	return 0;
> +}
> +
> +static int visconti_csi2rx_init_state(struct v4l2_subdev *sd, struct v4l2_subdev_state *sd_state)
> +{
> +	struct v4l2_mbus_framefmt *sink_fmt, *src_fmt;
> +
> +	sink_fmt = v4l2_subdev_state_get_format(sd_state, VISCONTI_CSI2RX_PAD_SINK);
> +	src_fmt = v4l2_subdev_state_get_format(sd_state, VISCONTI_CSI2RX_PAD_SRC);
> +
> +	sink_fmt->width = VISCONTI_CSI2RX_DEF_WIDTH;
> +	sink_fmt->height = VISCONTI_CSI2RX_DEF_HEIGHT;
> +	sink_fmt->field = V4L2_FIELD_NONE;
> +	sink_fmt->code = visconti_csi2rx_formats[0].code;

Please also initialize the colourspace fields. V4L2_COLORSPACE_RAW,
V4L2_XFER_FUNC_NONE, V4L2_YCBCR_ENC_601 and V4L2_QUANTIZATION_FULL_RANGE
should be appropriate defaults.

> +
> +	*src_fmt = *sink_fmt;
> +
> +	return 0;
> +}
> +
> +static int visconti_csi2rx_set_pad_format(struct v4l2_subdev *sd,
> +					  struct v4l2_subdev_state *sd_state,
> +					  struct v4l2_subdev_format *fmt)
> +{
> +	struct v4l2_mbus_framefmt *sink_fmt, *src_fmt;
> +
> +	/* SRC PAD has the same format as SINK PAD */
> +	if (fmt->pad == 1)

	if (fmt->pad == VISCONTI_CSI2RX_PAD_SRC)

> +		return v4l2_subdev_get_fmt(sd, sd_state, fmt);
> +
> +	sink_fmt = v4l2_subdev_state_get_format(sd_state, VISCONTI_CSI2RX_PAD_SINK);
> +
> +	*sink_fmt = fmt->format;
> +	sink_fmt->width = clamp_t(u32, fmt->format.width, VISCONTI_CSI2RX_MIN_WIDTH,
> +				  VISCONTI_CSI2RX_MAX_WIDTH);
> +	sink_fmt->height = clamp_t(u32, fmt->format.height, VISCONTI_CSI2RX_MIN_HEIGHT,
> +				   VISCONTI_CSI2RX_MAX_HEIGHT);
> +	if (!fmt_for_mbus_code(sink_fmt->code))
> +		sink_fmt->code = visconti_csi2rx_formats[0].code;
> +	fmt->format = *sink_fmt;
> +
> +	/* source pad should have the same format */
> +	src_fmt = v4l2_subdev_state_get_format(sd_state, VISCONTI_CSI2RX_PAD_SRC);
> +	*src_fmt = *sink_fmt;
> +
> +	return 0;
> +}
> +
> +static const struct media_entity_operations visconti_csi2rx_entity_ops = {
> +	.link_validate = v4l2_subdev_link_validate,
> +};
> +
> +static const struct v4l2_subdev_video_ops visconti_csi2rx_video_ops = {
> +	.s_stream = v4l2_subdev_s_stream_helper,

As the only driver that will use this CSI-2 RX is the VIIF driver, and
that driver uses v4l2_subdev_enable_streams(), .s_stream() will never be
called. You can drop the v4l2_subdev_video_ops.

> +};
> +
> +static const struct v4l2_subdev_pad_ops visconti_csi2rx_pad_ops = {
> +	.enum_mbus_code = visconti_csi2rx_enum_mbus_code,

You also need to implement .enum_frame_size()

> +	.disable_streams = visconti_csi2rx_disable_streams,
> +	.enable_streams = visconti_csi2rx_enable_streams,
> +	.get_fmt = v4l2_subdev_get_fmt,
> +	.set_fmt = visconti_csi2rx_set_pad_format,
> +};
> +
> +static const struct v4l2_subdev_ops visconti_csi2rx_subdev_ops = {
> +	.video = &visconti_csi2rx_video_ops,
> +	.pad = &visconti_csi2rx_pad_ops,
> +};
> +
> +static const struct v4l2_subdev_internal_ops visconti_csi2rx_internal_ops = {
> +	.init_state = visconti_csi2rx_init_state,
> +};
> +
> +static int visconti_csi2rx_notify_bound(struct v4l2_async_notifier *notifier,
> +					struct v4l2_subdev *subdev,
> +					struct v4l2_async_connection *asc)
> +{
> +	struct visconti_csi2rx *priv = notifier_to_csi2(notifier);
> +	int pad;
> +
> +	pad = media_entity_get_fwnode_pad(&subdev->entity, asc->match.fwnode, MEDIA_PAD_FL_SOURCE);
> +	if (pad < 0) {
> +		dev_err(priv->dev, "Failed to find pad for %s\n", subdev->name);
> +		return pad;
> +	}
> +
> +	priv->remote = subdev;
> +	priv->remote_pad = pad;
> +
> +	return media_create_pad_link(&subdev->entity, pad, &priv->subdev.entity, 0,
> +				     MEDIA_LNK_FL_ENABLED);

Can you have multiple sources connected to the same CSI-2 receiver ? If
not, you can make the link to the source immutable.

> +}
> +
> +static void visconti_csi2rx_notify_unbind(struct v4l2_async_notifier *notifier,
> +					  struct v4l2_subdev *subdev,
> +					  struct v4l2_async_connection *asc)
> +{
> +	struct visconti_csi2rx *priv = notifier_to_csi2(notifier);
> +
> +	priv->remote = NULL;
> +}
> +
> +static const struct v4l2_async_notifier_operations visconti_csi2rx_notify_ops = {
> +	.bound = visconti_csi2rx_notify_bound,
> +	.unbind = visconti_csi2rx_notify_unbind,
> +};
> +
> +static int visconti_csi2rx_parse_v4l2(struct visconti_csi2rx *priv,
> +				      struct v4l2_fwnode_endpoint *vep)
> +{
> +	/* Only port 0 endpoint 0 is valid. */
> +	if (vep->base.port || vep->base.id)
> +		return -ENOTCONN;

You call fwnode_graph_get_endpoint_by_id() with port and endpoint set to
0, so I think you can drop this check.

> +
> +	priv->lanes = vep->bus.mipi_csi2.num_data_lanes;
> +
> +	/* got trouble */
> +	if (vep->bus_type != V4L2_MBUS_CSI2_DPHY) {
> +		dev_err(priv->dev, "Specified bus type is not supported\n");

If you only support D-PHY, then set the bus_type to V4L2_MBUS_CSI2_DPHY
instead of V4L2_MBUS_UNKNOWN in visconti_csi2rx_parse_dt().
v4l2_fwnode_endpoint_parse() will return an error if the bus type is not
D-PHY, and you can drop this check.

> +		return -EINVAL;
> +	}
> +
> +	if (priv->lanes != 1 && priv->lanes != 2 && priv->lanes != 4) {
> +		dev_err(priv->dev, "Unsupported number of data-lanes for D-PHY: %u\n", priv->lanes);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int visconti_csi2rx_parse_dt(struct visconti_csi2rx *priv)
> +{
> +	struct v4l2_async_connection *asc;
> +	struct fwnode_handle *fwnode;
> +	struct fwnode_handle *ep;
> +	struct v4l2_fwnode_endpoint v4l2_ep = {
> +		.bus_type = V4L2_MBUS_UNKNOWN,
> +	};
> +	int ret;
> +
> +	ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(priv->dev), 0, 0, 0);
> +	if (!ep) {
> +		dev_err(priv->dev, "Not connected to subdevice\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = v4l2_fwnode_endpoint_parse(ep, &v4l2_ep);
> +	if (ret) {
> +		dev_err(priv->dev, "Could not parse v4l2 endpoint\n");
> +		fwnode_handle_put(ep);
> +		return -EINVAL;
> +	}
> +
> +	ret = visconti_csi2rx_parse_v4l2(priv, &v4l2_ep);

I would inline what is left of that function in here.

> +	if (ret) {
> +		fwnode_handle_put(ep);
> +		return ret;
> +	}
> +
> +	fwnode = fwnode_graph_get_remote_endpoint(ep);
> +	fwnode_handle_put(ep);
> +
> +	v4l2_async_subdev_nf_init(&priv->notifier, &priv->subdev);
> +	priv->notifier.ops = &visconti_csi2rx_notify_ops;
> +
> +	asc = v4l2_async_nf_add_fwnode(&priv->notifier, fwnode, struct v4l2_async_connection);
> +	fwnode_handle_put(fwnode);
> +	if (IS_ERR(asc))
> +		return PTR_ERR(asc);
> +
> +	ret = v4l2_async_nf_register(&priv->notifier);
> +	if (ret)
> +		v4l2_async_nf_cleanup(&priv->notifier);
> +
> +	return ret;
> +}
> +
> +static irqreturn_t visconti_csi2rx_irq(int irq, void *dev_id)
> +{
> +	struct visconti_csi2rx *priv = dev_id;
> +	u32 event;
> +
> +	event = visconti_csi2rx_read(priv, REG_CSI2RX_INT_ST_MAIN);
> +	dev_err(priv->dev, "CSI2RX error 0x%x.\n", event);

Should this be at least rate-limited ?

> +
> +	return IRQ_HANDLED;
> +}
> +
> +static const struct of_device_id visconti_csi2rx_of_table[] = {
> +	{
> +		.compatible = "toshiba,visconti5-csi2rx",
> +	},
> +	{},

	{ /* Sentinel */ },

is customary. You can also drop the trailing comma, as there should
never be any entry after this one.

> +};
> +
> +static int visconti_csi2rx_probe(struct platform_device *pdev)
> +{
> +	struct visconti_csi2rx *priv;
> +	int irq, ret;
> +
> +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->dev = &pdev->dev;
> +
> +	priv->base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(priv->base)) {
> +		dev_err(priv->dev, "Failed to get registers\n");

devm_platform_ioremap_resource() prints an error message already, you
can drop this one.

> +		return PTR_ERR(priv->base);
> +	}
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0)
> +		return irq;

Here, on the other hand, an error message would be useful. You can use
dev_err_probe():

		return dev_err_probe(priv->dev, irq, "Failed to get IRQ\n");

> +	ret = devm_request_irq(&pdev->dev, irq, visconti_csi2rx_irq, 0, KBUILD_MODNAME, priv);
> +	priv->irq = irq;
> +	if (ret) {
> +		dev_err(priv->dev, "request irq failed: %d\n", ret);
> +		return ret;
> +	}
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	ret = visconti_csi2rx_parse_dt(priv); /*this function does v4l2_async_nf_register */
> +	if (ret)
> +		return ret;
> +
> +	priv->subdev.owner = THIS_MODULE;

Not needed, this is handled by v4l2_async_register_subdev()

> +	priv->subdev.dev = &pdev->dev;
> +	v4l2_subdev_init(&priv->subdev, &visconti_csi2rx_subdev_ops);
> +	v4l2_set_subdevdata(&priv->subdev, &pdev->dev);
> +	snprintf(priv->subdev.name, sizeof(priv->subdev.name), "%s %s", KBUILD_MODNAME,
> +		 dev_name(&pdev->dev));
> +
> +	priv->subdev.internal_ops = &visconti_csi2rx_internal_ops;
> +	priv->subdev.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	priv->subdev.entity.function = MEDIA_ENT_F_PROC_VIDEO_PIXEL_FORMATTER;

MEDIA_ENT_F_VID_IF_BRIDGE seems more appropriate.

> +	priv->subdev.entity.ops = &visconti_csi2rx_entity_ops;
> +
> +	priv->pads[VISCONTI_CSI2RX_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
> +	priv->pads[VISCONTI_CSI2RX_PAD_SRC].flags = MEDIA_PAD_FL_SOURCE;
> +
> +	ret = media_entity_pads_init(&priv->subdev.entity, VISCONTI_CSI2RX_PAD_NUM, priv->pads);

	ret = media_entity_pads_init(&priv->subdev.entity, ARRAY_SIZE(priv->pads), 
				     priv->pads);


> +	if (ret)
> +		goto err_cleanup_async;
> +
> +	ret = v4l2_subdev_init_finalize(&priv->subdev);
> +	if (ret)
> +		goto err_cleanup_media_entity;
> +
> +	ret = v4l2_async_register_subdev(&priv->subdev);
> +	if (ret < 0)
> +		goto err_cleanup_subdev_state;
> +
> +	return 0;
> +
> +err_cleanup_subdev_state:
> +	v4l2_subdev_cleanup(&priv->subdev);
> +
> +err_cleanup_media_entity:
> +	media_entity_cleanup(&priv->subdev.entity);
> +
> +err_cleanup_async:
> +	v4l2_async_nf_unregister(&priv->notifier);
> +	v4l2_async_nf_cleanup(&priv->notifier);
> +
> +	return ret;
> +}
> +
> +static void visconti_csi2rx_remove(struct platform_device *pdev)
> +{
> +	struct visconti_csi2rx *priv = platform_get_drvdata(pdev);
> +
> +	v4l2_async_nf_unregister(&priv->notifier);
> +	v4l2_async_nf_cleanup(&priv->notifier);
> +	v4l2_async_unregister_subdev(&priv->subdev);
> +
> +	v4l2_subdev_cleanup(&priv->subdev);
> +	media_entity_cleanup(&priv->subdev.entity);
> +}
> +
> +static struct platform_driver visconti_csi2rx_driver = {
> +	.probe = visconti_csi2rx_probe,
> +	.remove = visconti_csi2rx_remove,
> +	.driver = {
> +		.name = "visconti_csi2rx_dev",
> +		.of_match_table = visconti_csi2rx_of_table,
> +	},
> +};
> +
> +module_platform_driver(visconti_csi2rx_driver);
> +
> +MODULE_AUTHOR("Yuji Ishikawa <yuji2.ishikawa@toshiba.co.jp>");
> +MODULE_DESCRIPTION("Toshiba Visconti CSI-2 receiver driver");
> +MODULE_LICENSE("Dual BSD/GPL");

-- 
Regards,

Laurent Pinchart