Re: [PATCH 2/2] max9286: Add MAX9286 driver

[Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>]

Hi Niklas,

This should be at least v5.

Did you take the last v4 and work from there?
I have made changes since the last posting. Did you get an update from
my branches?

What changes have you made to this posting compared to whichever
patch-base you have taken to start from?

--
Kieran



On 09/08/2019 05:05, Niklas Söderlund wrote:
> The MAX9286 is a 4-channel GMSL deserializer with coax or STP input and
> CSI-2 output. The device supports multicamera streaming applications,
> and features the ability to synchronise the attached cameras. The
> driver however limits the number of cameras to one as there are no way
> to express in V4L2 today that multiple video streams are transmitted
> over one CSI-2 bus.
> 
> CSI-2 output can be configured with 1 to 4 lanes, and a control channel
> is supported over I2C, which implements an I2C mux to facilitate
> communications with connected cameras across the reverse control
> channel.
> 
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> ---
>  MAINTAINERS                 |   10 +
>  drivers/media/i2c/Kconfig   |   11 +
>  drivers/media/i2c/Makefile  |    1 +
>  drivers/media/i2c/max9286.c | 1081 +++++++++++++++++++++++++++++++++++
>  4 files changed, 1103 insertions(+)
>  create mode 100644 drivers/media/i2c/max9286.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 6426db5198f05377..f8f028811feee489 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9746,6 +9746,16 @@ F:	Documentation/devicetree/bindings/hwmon/max6697.txt
>  F:	drivers/hwmon/max6697.c
>  F:	include/linux/platform_data/max6697.h
>  
> +MAX9286 QUAD GMSL DESERIALIZER DRIVER
> +M:	Jacopo Mondi <jacopo+renesas@jmondi.org>
> +M:	Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> +M:	Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> +M:	Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> +L:	linux-media@vger.kernel.org
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/media/i2c/maxim,max9286.txt
> +F:	drivers/media/i2c/max9286.c
> +
>  MAX9860 MONO AUDIO VOICE CODEC DRIVER
>  M:	Peter Rosin <peda@axentia.se>
>  L:	alsa-devel@alsa-project.org (moderated for non-subscribers)
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 79ce9ec6fc1be1e6..c20b151a16e64349 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -439,6 +439,17 @@ config VIDEO_VPX3220
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called vpx3220.
>  
> +config VIDEO_MAX9286
> +	tristate "Maxim MAX9286 GMSL deserializer support"
> +	depends on I2C && I2C_MUX
> +	depends on VIDEO_V4L2_SUBDEV_API && MEDIA_CONTROLLER
> +	select V4L2_FWNODE
> +	help
> +	  This driver supports the Maxim MAX9286 GMSL deserializer.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called max9286.
> +
>  comment "Video and audio decoders"
>  
>  config VIDEO_SAA717X
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index fd4ea86dedd5df44..25b3c7e5becfa714 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -114,5 +114,6 @@ obj-$(CONFIG_VIDEO_IMX274)	+= imx274.o
>  obj-$(CONFIG_VIDEO_IMX319)	+= imx319.o
>  obj-$(CONFIG_VIDEO_IMX355)	+= imx355.o
>  obj-$(CONFIG_VIDEO_ST_MIPID02) += st-mipid02.o
> +obj-$(CONFIG_VIDEO_MAX9286)	+= max9286.o
>  
>  obj-$(CONFIG_SDR_MAX2175) += max2175.o
> diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
> new file mode 100644
> index 0000000000000000..debd11ac269d28ca
> --- /dev/null
> +++ b/drivers/media/i2c/max9286.c
> @@ -0,0 +1,1081 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Maxim MAX9286 GMSL Deserializer Driver
> + *
> + * Copyright (C) 2017-2018 Jacopo Mondi
> + * Copyright (C) 2017-2018 Kieran Bingham
> + * Copyright (C) 2017-2018 Laurent Pinchart
> + * Copyright (C) 2017-2018 Niklas Söderlund
> + * Copyright (C) 2016 Renesas Electronics Corporation
> + * Copyright (C) 2015 Cogent Embedded, Inc.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/fwnode.h>
> +#include <linux/i2c.h>
> +#include <linux/i2c-mux.h>
> +#include <linux/module.h>
> +#include <linux/of_graph.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/slab.h>
> +
> +#include <media/v4l2-async.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-fwnode.h>
> +#include <media/v4l2-subdev.h>
> +
> +/* Register 0x00 */
> +#define MAX9286_MSTLINKSEL_AUTO		(7 << 5)
> +#define MAX9286_MSTLINKSEL(n)		((n) << 5)
> +#define MAX9286_EN_VS_GEN		BIT(4)
> +#define MAX9286_LINKEN(n)		(1 << (n))
> +/* Register 0x01 */
> +#define MAX9286_FSYNCMODE_ECU		(3 << 6)
> +#define MAX9286_FSYNCMODE_EXT		(2 << 6)
> +#define MAX9286_FSYNCMODE_INT_OUT	(1 << 6)
> +#define MAX9286_FSYNCMODE_INT_HIZ	(0 << 6)
> +#define MAX9286_GPIEN			BIT(5)
> +#define MAX9286_ENLMO_RSTFSYNC		BIT(2)
> +#define MAX9286_FSYNCMETH_AUTO		(2 << 0)
> +#define MAX9286_FSYNCMETH_SEMI_AUTO	(1 << 0)
> +#define MAX9286_FSYNCMETH_MANUAL	(0 << 0)
> +#define MAX9286_REG_FSYNC_PERIOD_L	0x06
> +#define MAX9286_REG_FSYNC_PERIOD_M	0x07
> +#define MAX9286_REG_FSYNC_PERIOD_H	0x08
> +/* Register 0x0a */
> +#define MAX9286_FWDCCEN(n)		(1 << ((n) + 4))
> +#define MAX9286_REVCCEN(n)		(1 << (n))
> +/* Register 0x0c */
> +#define MAX9286_HVEN			BIT(7)
> +#define MAX9286_EDC_6BIT_HAMMING	(2 << 5)
> +#define MAX9286_EDC_6BIT_CRC		(1 << 5)
> +#define MAX9286_EDC_1BIT_PARITY		(0 << 5)
> +#define MAX9286_DESEL			BIT(4)
> +#define MAX9286_INVVS			BIT(3)
> +#define MAX9286_INVHS			BIT(2)
> +#define MAX9286_HVSRC_D0		(2 << 0)
> +#define MAX9286_HVSRC_D14		(1 << 0)
> +#define MAX9286_HVSRC_D18		(0 << 0)
> +/* Register 0x12 */
> +#define MAX9286_CSILANECNT(n)		(((n) - 1) << 6)
> +#define MAX9286_CSIDBL			BIT(5)
> +#define MAX9286_DBL			BIT(4)
> +#define MAX9286_DATATYPE_USER_8BIT	(11 << 0)
> +#define MAX9286_DATATYPE_USER_YUV_12BIT	(10 << 0)
> +#define MAX9286_DATATYPE_USER_24BIT	(9 << 0)
> +#define MAX9286_DATATYPE_RAW14		(8 << 0)
> +#define MAX9286_DATATYPE_RAW11		(7 << 0)
> +#define MAX9286_DATATYPE_RAW10		(6 << 0)
> +#define MAX9286_DATATYPE_RAW8		(5 << 0)
> +#define MAX9286_DATATYPE_YUV422_10BIT	(4 << 0)
> +#define MAX9286_DATATYPE_YUV422_8BIT	(3 << 0)
> +#define MAX9286_DATATYPE_RGB555		(2 << 0)
> +#define MAX9286_DATATYPE_RGB565		(1 << 0)
> +#define MAX9286_DATATYPE_RGB888		(0 << 0)
> +/* Register 0x15 */
> +#define MAX9286_VC(n)			((n) << 5)
> +#define MAX9286_VCTYPE			BIT(4)
> +#define MAX9286_CSIOUTEN		BIT(3)
> +#define MAX9286_0X15_RESV		(3 << 0)
> +/* Register 0x1b */
> +#define MAX9286_SWITCHIN(n)		(1 << ((n) + 4))
> +#define MAX9286_ENEQ(n)			(1 << (n))
> +/* Register 0x27 */
> +#define MAX9286_LOCKED			BIT(7)
> +/* Register 0x31 */
> +#define MAX9286_FSYNC_LOCKED		BIT(6)
> +/* Register 0x34 */
> +#define MAX9286_I2CLOCACK		BIT(7)
> +#define MAX9286_I2CSLVSH_1046NS_469NS	(3 << 5)
> +#define MAX9286_I2CSLVSH_938NS_352NS	(2 << 5)
> +#define MAX9286_I2CSLVSH_469NS_234NS	(1 << 5)
> +#define MAX9286_I2CSLVSH_352NS_117NS	(0 << 5)
> +#define MAX9286_I2CMSTBT_837KBPS	(7 << 2)
> +#define MAX9286_I2CMSTBT_533KBPS	(6 << 2)
> +#define MAX9286_I2CMSTBT_339KBPS	(5 << 2)
> +#define MAX9286_I2CMSTBT_173KBPS	(4 << 2)
> +#define MAX9286_I2CMSTBT_105KBPS	(3 << 2)
> +#define MAX9286_I2CMSTBT_84KBPS		(2 << 2)
> +#define MAX9286_I2CMSTBT_28KBPS		(1 << 2)
> +#define MAX9286_I2CMSTBT_8KBPS		(0 << 2)
> +#define MAX9286_I2CSLVTO_NONE		(3 << 0)
> +#define MAX9286_I2CSLVTO_1024US		(2 << 0)
> +#define MAX9286_I2CSLVTO_256US		(1 << 0)
> +#define MAX9286_I2CSLVTO_64US		(0 << 0)
> +/* Register 0x3b */
> +#define MAX9286_REV_TRF(n)		((n) << 4)
> +#define MAX9286_REV_AMP(n)		((((n) - 30) / 10) << 1) /* in mV */
> +#define MAX9286_REV_AMP_X		BIT(0)
> +/* Register 0x3f */
> +#define MAX9286_EN_REV_CFG		BIT(6)
> +#define MAX9286_REV_FLEN(n)		((n) - 20)
> +/* Register 0x49 */
> +#define MAX9286_VIDEO_DETECT_MASK	0x0f
> +/* Register 0x69 */
> +#define MAX9286_LFLTBMONMASKED		BIT(7)
> +#define MAX9286_LOCKMONMASKED		BIT(6)
> +#define MAX9286_AUTOCOMBACKEN		BIT(5)
> +#define MAX9286_AUTOMASKEN		BIT(4)
> +#define MAX9286_MASKLINK(n)		((n) << 0)
> +
> +#define MAX9286_NUM_GMSL		4
> +#define MAX9286_N_SINKS			4
> +#define MAX9286_N_PADS			5
> +#define MAX9286_SRC_PAD			4
> +
> +#define MAXIM_I2C_I2C_SPEED_400KHZ	MAX9286_I2CMSTBT_339KBPS
> +#define MAXIM_I2C_I2C_SPEED_100KHZ	MAX9286_I2CMSTBT_105KBPS
> +#define MAXIM_I2C_SPEED			MAXIM_I2C_I2C_SPEED_100KHZ
> +
> +struct max9286_source {
> +	struct v4l2_async_subdev asd;
> +	struct v4l2_subdev *sd;
> +	struct fwnode_handle *fwnode;
> +};
> +
> +#define asd_to_max9286_source(_asd) \
> +	container_of(_asd, struct max9286_source, asd)
> +
> +struct max9286_priv {
> +	struct i2c_client *client;
> +	struct v4l2_subdev sd;
> +	struct media_pad pads[MAX9286_N_PADS];
> +	struct regulator *regulator;
> +	bool poc_enabled;
> +	int streaming;
> +
> +	struct i2c_mux_core *mux;
> +	unsigned int mux_channel;
> +
> +	struct v4l2_ctrl_handler ctrls;
> +
> +	struct v4l2_mbus_framefmt fmt[MAX9286_N_SINKS];
> +
> +	unsigned int nsources;
> +	unsigned int source_mask;
> +	unsigned int route_mask;
> +	unsigned int csi2_data_lanes;
> +	struct max9286_source sources[MAX9286_NUM_GMSL];
> +	struct v4l2_async_notifier notifier;
> +};
> +
> +static struct max9286_source *next_source(struct max9286_priv *priv,
> +					  struct max9286_source *source)
> +{
> +	if (!source)
> +		source = &priv->sources[0];
> +	else
> +		source++;
> +
> +	for (; source < &priv->sources[MAX9286_NUM_GMSL]; source++) {
> +		if (source->fwnode)
> +			return source;
> +	}
> +
> +	return NULL;
> +}
> +
> +#define for_each_source(max9286, source) \
> +	for (source = NULL; (source = next_source(max9286, source)); )
> +
> +#define to_index(max9286, source) (source - &max9286->sources[0])
> +
> +static inline struct max9286_priv *sd_to_max9286(struct v4l2_subdev *sd)
> +{
> +	return container_of(sd, struct max9286_priv, sd);
> +}
> +
> +/* -----------------------------------------------------------------------------
> + * I2C IO
> + */
> +
> +static int max9286_read(struct max9286_priv *priv, u8 reg)
> +{
> +	int ret;
> +
> +	ret = i2c_smbus_read_byte_data(priv->client, reg);
> +	if (ret < 0)
> +		dev_err(&priv->client->dev,
> +			"%s: register 0x%02x read failed (%d)\n",
> +			__func__, reg, ret);
> +
> +	return ret;
> +}
> +
> +static int max9286_write(struct max9286_priv *priv, u8 reg, u8 val)
> +{
> +	int ret;
> +
> +	ret = i2c_smbus_write_byte_data(priv->client, reg, val);
> +	if (ret < 0)
> +		dev_err(&priv->client->dev,
> +			"%s: register 0x%02x write failed (%d)\n",
> +			__func__, reg, ret);
> +
> +	return ret;
> +}
> +
> +/* -----------------------------------------------------------------------------
> + * I2C Multiplexer
> + */
> +
> +static int max9286_i2c_mux_close(struct max9286_priv *priv)
> +{
> +	/* FIXME: See note in max9286_i2c_mux_select() */
> +	if (priv->streaming)
> +		return 0;
> +	/*
> +	 * Ensure that both the forward and reverse channel are disabled on the
> +	 * mux, and that the channel ID is invalidated to ensure we reconfigure
> +	 * on the next select call.
> +	 */
> +	priv->mux_channel = -1;
> +	max9286_write(priv, 0x0a, 0x00);
> +	usleep_range(3000, 5000);
> +
> +	return 0;
> +}
> +
> +static int max9286_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
> +{
> +	struct max9286_priv *priv = i2c_mux_priv(muxc);
> +
> +	/*
> +	 * FIXME: This state keeping is a hack and do the job. It should
> +	 * be should be reworked. One option to consider is that once all
> +	 * cameras are programmed the mux selection logic should be disabled
> +	 * and all all reverse and forward channels enable all the time.
> +	 *
> +	 * In any case this logic with a int that have two states should be
> +	 * reworked!
> +	 */
> +	if (priv->streaming == 1) {
> +		max9286_write(priv, 0x0a, 0xff);
> +		priv->streaming = 2;
> +		return 0;
> +	} else if (priv->streaming == 2) {
> +		return 0;
> +	}
> +
> +	if (priv->mux_channel == chan)
> +		return 0;
> +
> +	priv->mux_channel = chan;
> +
> +	max9286_write(priv, 0x0a,
> +		      MAX9286_FWDCCEN(chan) | MAX9286_REVCCEN(chan));
> +
> +	/*
> +	 * We must sleep after any change to the forward or reverse channel
> +	 * configuration.
> +	 */
> +	usleep_range(3000, 5000);
> +
> +	return 0;
> +}
> +
> +static int max9286_i2c_mux_init(struct max9286_priv *priv)
> +{
> +	struct max9286_source *source;
> +	int ret;
> +
> +	if (!i2c_check_functionality(priv->client->adapter,
> +				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
> +		return -ENODEV;
> +
> +	priv->mux = i2c_mux_alloc(priv->client->adapter, &priv->client->dev,
> +				 priv->nsources, 0, I2C_MUX_LOCKED,
> +				 max9286_i2c_mux_select, NULL);
> +	if (!priv->mux)
> +		return -ENOMEM;
> +
> +	priv->mux->priv = priv;
> +
> +	for_each_source(priv, source) {
> +		unsigned int index = to_index(priv, source);
> +
> +		ret = i2c_mux_add_adapter(priv->mux, 0, index, 0);
> +		if (ret < 0)
> +			goto error;
> +	}
> +
> +	return 0;
> +
> +error:
> +	i2c_mux_del_adapters(priv->mux);
> +	return ret;
> +}
> +
> +static void max9286_configure_i2c(struct max9286_priv *priv, bool localack)
> +{
> +	u8 config = MAX9286_I2CSLVSH_469NS_234NS | MAX9286_I2CSLVTO_1024US |
> +		    MAXIM_I2C_SPEED;
> +
> +	if (localack)
> +		config |= MAX9286_I2CLOCACK;
> +
> +	max9286_write(priv, 0x34, config);
> +	usleep_range(3000, 5000);
> +}
> +
> +/* -----------------------------------------------------------------------------
> + * V4L2 Subdev
> + */
> +
> +static int max9286_notify_bound(struct v4l2_async_notifier *notifier,
> +				struct v4l2_subdev *subdev,
> +				struct v4l2_async_subdev *asd)
> +{
> +	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
> +	struct max9286_source *source = asd_to_max9286_source(asd);
> +	unsigned int index = to_index(priv, source);
> +	unsigned int src_pad;
> +	int ret;
> +
> +	ret = media_entity_get_fwnode_pad(&subdev->entity,
> +					  source->fwnode,
> +					  MEDIA_PAD_FL_SOURCE);
> +	if (ret < 0) {
> +		dev_err(&priv->client->dev,
> +			"Failed to find pad for %s\n", subdev->name);
> +		return ret;
> +	}
> +
> +	source->sd = subdev;
> +	src_pad = ret;
> +
> +	ret = media_create_pad_link(&source->sd->entity, src_pad,
> +				    &priv->sd.entity, index,
> +				    MEDIA_LNK_FL_ENABLED |
> +				    MEDIA_LNK_FL_IMMUTABLE);
> +	if (ret) {
> +		dev_err(&priv->client->dev,
> +			"Unable to link %s:%u -> %s:%u\n",
> +			source->sd->name, src_pad, priv->sd.name, index);
> +		return ret;
> +	}
> +
> +	dev_dbg(&priv->client->dev, "Bound %s pad: %u on index %u\n",
> +		subdev->name, src_pad, index);
> +
> +	return 0;
> +}
> +
> +static void max9286_notify_unbind(struct v4l2_async_notifier *notifier,
> +				  struct v4l2_subdev *subdev,
> +				  struct v4l2_async_subdev *asd)
> +{
> +	struct max9286_source *source = asd_to_max9286_source(asd);
> +
> +	source->sd = NULL;
> +}
> +
> +static const struct v4l2_async_notifier_operations max9286_notify_ops = {
> +	.bound = max9286_notify_bound,
> +	.unbind = max9286_notify_unbind,
> +};
> +
> +/*
> + * max9286_check_video_links() - Make sure video links are detected and locked
> + *
> + * Performs safety checks on video link status. Make sure they are detected
> + * and all enabled links are locked.
> + *
> + * Returns 0 for success, -EIO for errors.
> + */
> +static int max9286_check_video_links(struct max9286_priv *priv)
> +{
> +	unsigned int i;
> +	int ret;
> +
> +	/*
> +	 * Make sure valid video links are detected.
> +	 * The delay is not characterized in de-serializer manual, wait up
> +	 * to 5 ms.
> +	 */
> +	for (i = 0; i < 10; i++) {
> +		ret = max9286_read(priv, 0x49);
> +		if (ret < 0)
> +			return -EIO;
> +
> +		if ((ret & MAX9286_VIDEO_DETECT_MASK) == priv->source_mask)
> +			break;
> +
> +		usleep_range(350, 500);
> +	}
> +
> +	if (i == 10) {
> +		dev_err(&priv->client->dev,
> +			"Unable to detect video links: 0x%02x\n", ret);
> +		return -EIO;
> +	}
> +
> +	/* Make sure all enabled links are locked (4ms max). */
> +	for (i = 0; i < 10; i++) {
> +		ret = max9286_read(priv, 0x27);
> +		if (ret < 0)
> +			return -EIO;
> +
> +		if (ret & MAX9286_LOCKED)
> +			break;
> +
> +		usleep_range(350, 450);
> +	}
> +
> +	if (i == 10) {
> +		dev_err(&priv->client->dev, "Not all enabled links locked\n");
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int max9286_s_stream(struct v4l2_subdev *sd, int enable)
> +{
> +	struct max9286_priv *priv = sd_to_max9286(sd);
> +	struct max9286_source *source;
> +	unsigned int i;
> +	bool sync = false;
> +	int ret;
> +
> +	if (enable) {
> +		/* FIXME: See note in max9286_i2c_mux_select() */
> +		priv->streaming = 1;
> +
> +		/* Start all cameras. */
> +		for_each_source(priv, source) {
> +			ret = v4l2_subdev_call(source->sd, video, s_stream, 1);
> +			if (ret)
> +				return ret;
> +		}
> +
> +		ret = max9286_check_video_links(priv);
> +		if (ret)
> +			return ret;
> +
> +		/*
> +		 * Wait until frame synchronization is locked.
> +		 *
> +		 * Manual says frame sync locking should take ~6 VTS.
> +		 * From pratical experience at least 8 are required. Give
> +		 * 12 complete frames time (~33ms at 30 fps) to achieve frame
> +		 * locking before returning error.
> +		 */
> +		for (i = 0; i < 36; i++) {
> +			if (max9286_read(priv, 0x31) & MAX9286_FSYNC_LOCKED) {
> +				sync = true;
> +				break;
> +			}
> +			usleep_range(9000, 11000);
> +		}
> +
> +		if (!sync) {
> +			dev_err(&priv->client->dev,
> +				"Failed to get frame synchronization\n");
> +			return -EINVAL;
> +		}
> +
> +		/*
> +		 * Enable CSI output, VC set according to link number.
> +		 * Bit 7 must be set (chip manual says it's 0 and reserved).
> +		 */
> +		max9286_write(priv, 0x15, 0x80 | MAX9286_VCTYPE |
> +			      MAX9286_CSIOUTEN | MAX9286_0X15_RESV);
> +	} else {
> +		max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_0X15_RESV);
> +
> +		/* Stop all cameras. */
> +		for_each_source(priv, source)
> +			v4l2_subdev_call(source->sd, video, s_stream, 0);
> +
> +		/* FIXME: See note in max9286_i2c_mux_select() */
> +		priv->streaming = 0;
> +	}
> +
> +	return 0;
> +}
> +
> +static int max9286_enum_mbus_code(struct v4l2_subdev *sd,
> +				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	if (code->pad || code->index > 0)
> +		return -EINVAL;
> +
> +	code->code = MEDIA_BUS_FMT_UYVY8_2X8;
> +
> +	return 0;
> +}
> +
> +static struct v4l2_mbus_framefmt *
> +max9286_get_pad_format(struct max9286_priv *priv,
> +		       struct v4l2_subdev_pad_config *cfg,
> +		       unsigned int pad, u32 which)
> +{
> +	switch (which) {
> +	case V4L2_SUBDEV_FORMAT_TRY:
> +		return v4l2_subdev_get_try_format(&priv->sd, cfg, pad);
> +	case V4L2_SUBDEV_FORMAT_ACTIVE:
> +		return &priv->fmt[pad];
> +	default:
> +		return NULL;
> +	}
> +}
> +
> +static int max9286_set_fmt(struct v4l2_subdev *sd,
> +			   struct v4l2_subdev_pad_config *cfg,
> +			   struct v4l2_subdev_format *format)
> +{
> +	struct max9286_priv *priv = sd_to_max9286(sd);
> +	struct v4l2_mbus_framefmt *cfg_fmt;
> +
> +	if (format->pad >= MAX9286_SRC_PAD)
> +		return -EINVAL;
> +
> +	/* Refuse non YUV422 formats as we hardcode DT to 8 bit YUV422 */
> +	switch (format->format.code) {
> +	case MEDIA_BUS_FMT_UYVY8_2X8:
> +	case MEDIA_BUS_FMT_VYUY8_2X8:
> +	case MEDIA_BUS_FMT_YUYV8_2X8:
> +	case MEDIA_BUS_FMT_YVYU8_2X8:
> +		break;
> +	default:
> +		format->format.code = MEDIA_BUS_FMT_YUYV8_2X8;
> +		break;
> +	}
> +
> +	cfg_fmt = max9286_get_pad_format(priv, cfg, format->pad, format->which);
> +	if (!cfg_fmt)
> +		return -EINVAL;
> +
> +	*cfg_fmt = format->format;
> +
> +	return 0;
> +}
> +
> +static int max9286_get_fmt(struct v4l2_subdev *sd,
> +			   struct v4l2_subdev_pad_config *cfg,
> +			   struct v4l2_subdev_format *format)
> +{
> +	struct max9286_priv *priv = sd_to_max9286(sd);
> +	struct v4l2_mbus_framefmt *cfg_fmt;
> +
> +	if (format->pad >= MAX9286_SRC_PAD)
> +		return -EINVAL;
> +
> +	cfg_fmt = max9286_get_pad_format(priv, cfg, format->pad, format->which);
> +	if (!cfg_fmt)
> +		return -EINVAL;
> +
> +	format->format = *cfg_fmt;
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_video_ops max9286_video_ops = {
> +	.s_stream	= max9286_s_stream,
> +};
> +
> +static const struct v4l2_subdev_pad_ops max9286_pad_ops = {
> +	.enum_mbus_code = max9286_enum_mbus_code,
> +	.get_fmt	= max9286_get_fmt,
> +	.set_fmt	= max9286_set_fmt,
> +};
> +
> +static const struct v4l2_subdev_ops max9286_subdev_ops = {
> +	.video		= &max9286_video_ops,
> +	.pad		= &max9286_pad_ops,
> +};
> +
> +static void max9286_init_format(struct v4l2_mbus_framefmt *fmt)
> +{
> +	fmt->width		= 1280;
> +	fmt->height		= 800;
> +	fmt->code		= MEDIA_BUS_FMT_UYVY8_2X8;
> +	fmt->colorspace		= V4L2_COLORSPACE_SRGB;
> +	fmt->field		= V4L2_FIELD_NONE;
> +	fmt->ycbcr_enc		= V4L2_YCBCR_ENC_DEFAULT;
> +	fmt->quantization	= V4L2_QUANTIZATION_DEFAULT;
> +	fmt->xfer_func		= V4L2_XFER_FUNC_DEFAULT;
> +}
> +
> +static int max9286_open(struct v4l2_subdev *subdev, struct v4l2_subdev_fh *fh)
> +{
> +	struct v4l2_mbus_framefmt *format;
> +	unsigned int i;
> +
> +	for (i = 0; i < MAX9286_N_SINKS; i++) {
> +		format = v4l2_subdev_get_try_format(subdev, fh->pad, i);
> +		max9286_init_format(format);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_internal_ops max9286_subdev_internal_ops = {
> +	.open = max9286_open,
> +};
> +
> +/* -----------------------------------------------------------------------------
> + * Probe/Remove
> + */
> +
> +static int max9286_setup(struct max9286_priv *priv)
> +{
> +	/*
> +	 * Link ordering values for all enabled links combinations. Orders must
> +	 * be assigned sequentially from 0 to the number of enabled links
> +	 * without leaving any hole for disabled links. We thus assign orders to
> +	 * enabled links first, and use the remaining order values for disabled
> +	 * links are all links must have a different order value;
> +	 */
> +	static const u8 link_order[] = {
> +		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxxx */
> +		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxx0 */
> +		(3 << 6) | (2 << 4) | (0 << 2) | (1 << 0), /* xx0x */
> +		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xx10 */
> +		(3 << 6) | (0 << 4) | (2 << 2) | (1 << 0), /* x0xx */
> +		(3 << 6) | (1 << 4) | (2 << 2) | (0 << 0), /* x1x0 */
> +		(3 << 6) | (1 << 4) | (0 << 2) | (2 << 0), /* x10x */
> +		(3 << 6) | (1 << 4) | (1 << 2) | (0 << 0), /* x210 */
> +		(0 << 6) | (3 << 4) | (2 << 2) | (1 << 0), /* 0xxx */
> +		(1 << 6) | (3 << 4) | (2 << 2) | (0 << 0), /* 1xx0 */
> +		(1 << 6) | (3 << 4) | (0 << 2) | (2 << 0), /* 1x0x */
> +		(2 << 6) | (3 << 4) | (1 << 2) | (0 << 0), /* 2x10 */
> +		(1 << 6) | (0 << 4) | (3 << 2) | (2 << 0), /* 10xx */
> +		(2 << 6) | (1 << 4) | (3 << 2) | (0 << 0), /* 21x0 */
> +		(2 << 6) | (1 << 4) | (0 << 2) | (3 << 0), /* 210x */
> +		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* 3210 */
> +	};
> +
> +	/*
> +	 * Set the I2C bus speed.
> +	 *
> +	 * Enable I2C Local Acknowledge during the probe sequences of the camera
> +	 * only. This should be disabled after the mux is initialised.
> +	 */
> +	max9286_configure_i2c(priv, true);
> +
> +	/*
> +	 * Reverse channel setup.
> +	 *
> +	 * - Enable custom reverse channel configuration (through register 0x3f)
> +	 *   and set the first pulse length to 35 clock cycles.
> +	 * - Increase the reverse channel amplitude to 170mV to accommodate the
> +	 *   high threshold enabled by the serializer driver.
> +	 */
> +	max9286_write(priv, 0x3f, MAX9286_EN_REV_CFG | MAX9286_REV_FLEN(35));
> +	max9286_write(priv, 0x3b, MAX9286_REV_TRF(1) | MAX9286_REV_AMP(70) |
> +		      MAX9286_REV_AMP_X);
> +
> +	/*
> +	 * Enable GMSL links, mask unused ones and autodetect link
> +	 * used as CSI clock source.
> +	 */
> +	max9286_write(priv, 0x00, MAX9286_MSTLINKSEL_AUTO | priv->route_mask);
> +	max9286_write(priv, 0x0b, link_order[priv->route_mask]);
> +	max9286_write(priv, 0x69, (0xf & ~priv->route_mask));
> +
> +	/*
> +	 * Video format setup:
> +	 * Disable CSI output, VC is set accordingly to Link number.
> +	 */
> +	max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_0X15_RESV);
> +
> +	/* Enable CSI-2 Lane D0-D3 only, DBL mode, YUV422 8-bit. */
> +	max9286_write(priv, 0x12, MAX9286_CSIDBL | MAX9286_DBL |
> +		      MAX9286_CSILANECNT(priv->csi2_data_lanes) |
> +		      MAX9286_DATATYPE_YUV422_8BIT);
> +
> +	/* Automatic: FRAMESYNC taken from the slowest Link. */
> +	max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ |
> +		      MAX9286_FSYNCMETH_AUTO);
> +
> +	/* Enable HS/VS encoding, use D14/15 for HS/VS, invert VS. */
> +	max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_INVVS |
> +		      MAX9286_HVSRC_D14);
> +
> +	/*
> +	 * Wait for 2ms to allow the link to resynchronize after the
> +	 * configuration change.
> +	 */
> +	usleep_range(2000, 5000);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id max9286_dt_ids[] = {
> +	{ .compatible = "maxim,max9286" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, max9286_dt_ids);
> +
> +static int max9286_init(struct device *dev)
> +{
> +	struct max9286_priv *priv;
> +	struct i2c_client *client;
> +	struct fwnode_handle *ep;
> +	unsigned int i;
> +	int ret;
> +
> +	/* Skip non-max9286 devices. */
> +	if (!dev->of_node || !of_match_node(max9286_dt_ids, dev->of_node))
> +		return 0;
> +
> +	client = to_i2c_client(dev);
> +	priv = i2c_get_clientdata(client);
> +
> +	/* Enable the bus power. */
> +	ret = regulator_enable(priv->regulator);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Unable to turn PoC on\n");
> +		return ret;
> +	}
> +
> +	priv->poc_enabled = true;
> +
> +	ret = max9286_setup(priv);
> +	if (ret) {
> +		dev_err(dev, "Unable to setup max9286\n");
> +		goto err_regulator;
> +	}
> +
> +	v4l2_i2c_subdev_init(&priv->sd, client, &max9286_subdev_ops);
> +	priv->sd.internal_ops = &max9286_subdev_internal_ops;
> +	priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +
> +	v4l2_ctrl_handler_init(&priv->ctrls, 1);
> +	/*
> +	 * FIXME: Compute the real pixel rate. The 50 MP/s value comes from the
> +	 * hardcoded frequency in the BSP CSI-2 receiver driver.
> +	 */
> +	v4l2_ctrl_new_std(&priv->ctrls, NULL, V4L2_CID_PIXEL_RATE,
> +			  50000000, 50000000, 1, 50000000);
> +	priv->sd.ctrl_handler = &priv->ctrls;
> +	ret = priv->ctrls.error;
> +	if (ret)
> +		goto err_regulator;
> +
> +	priv->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
> +
> +	priv->pads[MAX9286_SRC_PAD].flags = MEDIA_PAD_FL_SOURCE;
> +	for (i = 0; i < MAX9286_SRC_PAD; i++)
> +		priv->pads[i].flags = MEDIA_PAD_FL_SINK;
> +	ret = media_entity_pads_init(&priv->sd.entity, MAX9286_N_PADS,
> +				     priv->pads);
> +	if (ret)
> +		goto err_regulator;
> +
> +	ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), MAX9286_SRC_PAD,
> +					     0, 0);
> +	if (!ep) {
> +		dev_err(dev, "Unable to retrieve endpoint on \"port@4\"\n");
> +		ret = -ENOENT;
> +		goto err_regulator;
> +	}
> +	priv->sd.fwnode = ep;
> +
> +	ret = v4l2_async_register_subdev(&priv->sd);
> +	if (ret < 0) {
> +		dev_err(dev, "Unable to register subdevice\n");
> +		goto err_put_node;
> +	}
> +
> +	ret = max9286_i2c_mux_init(priv);
> +	if (ret) {
> +		dev_err(dev, "Unable to initialize I2C multiplexer\n");
> +		goto err_subdev_unregister;
> +	}
> +
> +	/*
> +	 * Re-configure I2C with local acknowledge disabled after cameras
> +	 * have probed.
> +	 */
> +	max9286_configure_i2c(priv, false);
> +
> +	/* Leave the mux channels disabled until they are selected. */
> +	max9286_i2c_mux_close(priv);
> +
> +	return 0;
> +
> +err_subdev_unregister:
> +	v4l2_async_unregister_subdev(&priv->sd);
> +	max9286_i2c_mux_close(priv);
> +err_put_node:
> +	fwnode_handle_put(ep);
> +err_regulator:
> +	regulator_disable(priv->regulator);
> +	priv->poc_enabled = false;
> +
> +	return ret;
> +}
> +
> +static struct device_node *max9286_get_i2c_by_id(struct device_node *parent,
> +						 u32 id)
> +{
> +	struct device_node *child;
> +
> +	for_each_child_of_node(parent, child) {
> +		u32 i2c_id = 0;
> +
> +		if (of_node_cmp(child->name, "i2c") != 0)
> +			continue;
> +		of_property_read_u32(child, "reg", &i2c_id);
> +		if (id == i2c_id)
> +			return child;
> +	}
> +
> +	return NULL;
> +}
> +
> +static int max9286_check_i2c_bus_by_id(struct device *dev, int id)
> +{
> +	struct device_node *i2c_np;
> +
> +	i2c_np = max9286_get_i2c_by_id(dev->of_node, id);
> +	if (!i2c_np) {
> +		dev_err(dev, "Failed to find corresponding i2c@%u\n", id);
> +		return -ENODEV;
> +	}
> +
> +	if (!of_device_is_available(i2c_np)) {
> +		dev_dbg(dev, "Skipping port %u with disabled I2C bus\n", id);
> +		of_node_put(i2c_np);
> +		return -ENODEV;
> +	}
> +
> +	of_node_put(i2c_np);
> +
> +	return 0;
> +}
> +
> +static void max9286_cleanup_dt(struct max9286_priv *priv)
> +{
> +	struct max9286_source *source;
> +
> +	/*
> +	 * Not strictly part of the DT, but the notifier is registered during
> +	 * max9286_parse_dt(), and the notifier holds references to the fwnodes
> +	 * thus the cleanup is here to mirror the registration.
> +	 */
> +	v4l2_async_notifier_unregister(&priv->notifier);
> +	v4l2_async_notifier_cleanup(&priv->notifier);
> +
> +	for_each_source(priv, source) {
> +		fwnode_handle_put(source->fwnode);
> +		source->fwnode = NULL;
> +	}
> +}
> +
> +static int max9286_parse_dt(struct max9286_priv *priv)
> +{
> +	struct device *dev = &priv->client->dev;
> +	struct device_node *ep_np = NULL;
> +	int ret;
> +
> +	v4l2_async_notifier_init(&priv->notifier);
> +
> +	for_each_endpoint_of_node(dev->of_node, ep_np) {
> +		struct max9286_source *source;
> +		struct of_endpoint ep;
> +
> +		of_graph_parse_endpoint(ep_np, &ep);
> +		dev_dbg(dev, "Endpoint %pOF on port %d",
> +			ep.local_node, ep.port);
> +
> +		if (ep.port > MAX9286_NUM_GMSL) {
> +			dev_err(dev, "Invalid endpoint %s on port %d",
> +				of_node_full_name(ep.local_node), ep.port);
> +			continue;
> +		}
> +
> +		/* For the source endpoint just parse the bus configuration. */
> +		if (ep.port == MAX9286_SRC_PAD) {
> +			struct v4l2_fwnode_endpoint vep = { .bus_type = 0 };
> +			int ret;
> +
> +			ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep_np),
> +							 &vep);
> +			if (ret)
> +				return ret;
> +
> +			if (vep.bus_type != V4L2_MBUS_CSI2_DPHY) {
> +				dev_err(dev,
> +					"Media bus %u type not supported\n",
> +					vep.bus_type);
> +				v4l2_fwnode_endpoint_free(&vep);
> +				return -EINVAL;
> +			}
> +
> +			priv->csi2_data_lanes =
> +				vep.bus.mipi_csi2.num_data_lanes;
> +			v4l2_fwnode_endpoint_free(&vep);
> +
> +			continue;
> +		}
> +
> +		/* Skip if the corresponding GMSL link is unavailable. */
> +		if (max9286_check_i2c_bus_by_id(dev, ep.port))
> +			continue;
> +
> +		if (priv->sources[ep.port].fwnode) {
> +			dev_err(dev,
> +				"Multiple port endpoints are not supported: %d",
> +				ep.port);
> +
> +			continue;
> +		}
> +
> +		source = &priv->sources[ep.port];
> +		source->fwnode = fwnode_graph_get_remote_endpoint(
> +						of_fwnode_handle(ep_np));
> +		if (!source->fwnode) {
> +			dev_err(dev,
> +				"Endpoint %pOF has no remote endpoint connection\n",
> +				ep.local_node);
> +
> +			continue;
> +		}
> +
> +		source->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
> +		source->asd.match.fwnode = source->fwnode;
> +
> +		ret = v4l2_async_notifier_add_subdev(&priv->notifier,
> +						     &source->asd);
> +		if (ret) {
> +			v4l2_async_notifier_cleanup(&priv->notifier);
> +			return ret;
> +		}
> +
> +		priv->source_mask |= BIT(ep.port);
> +		priv->nsources++;
> +	}
> +
> +	/* Do not register the subdev notifier if there are no devices. */
> +	if (!priv->nsources)
> +		return 0;
> +
> +	priv->route_mask = priv->source_mask;
> +	priv->notifier.ops = &max9286_notify_ops;
> +
> +	ret = v4l2_async_subdev_notifier_register(&priv->sd, &priv->notifier);
> +	if (ret)
> +		v4l2_async_notifier_cleanup(&priv->notifier);
> +
> +	return 0;
> +}
> +
> +static int max9286_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *did)
> +{
> +	struct max9286_priv *priv;
> +	unsigned int i;
> +	int ret;
> +
> +	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->client = client;
> +	i2c_set_clientdata(client, priv);
> +
> +	for (i = 0; i < MAX9286_N_SINKS; i++)
> +		max9286_init_format(&priv->fmt[i]);
> +
> +	ret = max9286_parse_dt(priv);
> +	if (ret)
> +		return ret;
> +
> +	priv->regulator = regulator_get(&client->dev, "poc");
> +	if (IS_ERR(priv->regulator)) {
> +		if (PTR_ERR(priv->regulator) != -EPROBE_DEFER)
> +			dev_err(&client->dev,
> +				"Unable to get PoC regulator (%ld)\n",
> +				PTR_ERR(priv->regulator));
> +		ret = PTR_ERR(priv->regulator);
> +		goto err_free;
> +	}
> +
> +	/*
> +	 * We can have multiple MAX9286 instances on the same physical I2C
> +	 * bus, and I2C children behind ports of separate MAX9286 instances
> +	 * having the same I2C address. As the MAX9286 starts by default with
> +	 * all ports enabled, we need to disable all ports on all MAX9286
> +	 * instances before proceeding to further initialize the devices and
> +	 * instantiate children.
> +	 *
> +	 * Start by just disabling all channels on the current device. Then,
> +	 * if all other MAX9286 on the parent bus have been probed, proceed
> +	 * to initialize them all, including the current one.
> +	 */
> +	max9286_i2c_mux_close(priv);
> +
> +	/*
> +	 * The MAX9286 initialises with auto-acknowledge enabled by default.
> +	 * This means that if multiple MAX9286 devices are connected to an I2C
> +	 * bus, another MAX9286 could ack I2C transfers meant for a device on
> +	 * the other side of the GMSL links for this MAX9286 (such as a
> +	 * MAX9271). To prevent that disable auto-acknowledge early on; it
> +	 * will be enabled later as needed.
> +	 */
> +	max9286_configure_i2c(priv, false);
> +
> +	ret = max9286_init(&client->dev);
> +	if (ret < 0)
> +		goto err_regulator;
> +
> +	return 0;
> +
> +err_regulator:
> +	regulator_put(priv->regulator);
> +	max9286_i2c_mux_close(priv);
> +	max9286_configure_i2c(priv, false);
> +err_free:
> +	max9286_cleanup_dt(priv);
> +	kfree(priv);
> +
> +	return ret;
> +}
> +
> +static int max9286_remove(struct i2c_client *client)
> +{
> +	struct max9286_priv *priv = i2c_get_clientdata(client);
> +
> +	i2c_mux_del_adapters(priv->mux);
> +
> +	fwnode_handle_put(priv->sd.fwnode);
> +	v4l2_async_unregister_subdev(&priv->sd);
> +
> +	if (priv->poc_enabled)
> +		regulator_disable(priv->regulator);
> +	regulator_put(priv->regulator);
> +
> +	max9286_cleanup_dt(priv);
> +	kfree(priv);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id max9286_id[] = {
> +	{ "max9286", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, max9286_id);
> +
> +static struct i2c_driver max9286_i2c_driver = {
> +	.driver	= {
> +		.name		= "max9286",
> +		.of_match_table	= of_match_ptr(max9286_dt_ids),
> +	},
> +	.probe		= max9286_probe,
> +	.remove		= max9286_remove,
> +	.id_table	= max9286_id,
> +};
> +
> +module_i2c_driver(max9286_i2c_driver);
> +
> +MODULE_DESCRIPTION("Maxim MAX9286 GMSL Deserializer Driver");
> +MODULE_AUTHOR("Jacopo Mondi, Kieran Bingham, Laurent Pinchart, Niklas Söderlund, Vladimir Barinov");
> +MODULE_LICENSE("GPL");
>