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SubjectRe: [PATCH v10 2/4] media: i2c: Add MAX9286 driver
On Fri, Jun 12, 2020 at 03:47:11PM +0100, Kieran Bingham 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.
>
> 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>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Thanks,
Mani

>
> --
> v2:
> - Fix MAINTAINERS entry
>
> This posting is released with the following modifications to work
> without Sakari's VC developments:
> - max9286_g_mbus_config() re-instated
> - max9286_get_frame_desc() is not bus/csi aware
> - max9286_{get,set}_routing() removed
>
> v3:
> - Initialise notifier with v4l2_async_notifier_init
> - Update for new mbus csi2 format V4L2_MBUS_CSI2_DPHY
>
> v4: - Re-introduce required code to function with the VC series.
>
> - Implement max9286_get_routing, max9286_set_routing
> - Remove max9286_g_mbus_config
>
> v5: (internal release)
> - Fix printk formatting for hex value
> - max9286->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE (add |)
> - MEDIA_ENT_F_PROC_VIDEO_PIXEL_FORMATTER -> MEDIA_ENT_F_VID_IF_BRIDGE
> - Remove 'device is bound' workaround
>
> v6:
> - v4l2_subdev_krouting instead of v4l2_subdev_routing separated
> to allow integration without the VC/V4L2-Mux series.
> - convert sd_to_max9286 to inline function
> - rename max9286_device to max9286_priv
> - Cleanup the v4l2_async_notifier
> - Extend MODULE_AUTHOR
> - Replace of_graph_get_endpoint_by_regs with fwnode_graph_get_endpoint_by_id
> - Pass default bus type when parsing fwnode endpoint (Manivannan Sadhasivam)
> - Use new YAML file reference in MAINTAINERS
> - Parse new i2c-mux node in max9286_get_i2c_by_id
> (This could/should be refactored to parse these separately first)
> - Spelling and calculation fixes in the FSYNC_LOCKED check comments
> - Identify each enabled i2c-mux channel in a single pass
> - max9286: Improve mux-state readbility [v2]
> - Fix frame sync lock durations
> - Add comment to describe /why/ we must open the mux in s_stream
> - use -EXDEV as return code for failed link synchronisation.
> - Fix reference counting of the dt nodeS
> - Convert to probe_new for I2C
> - Remove redundant max9286_i2c_mux_state
> - Provide optional enable-gpio (max9286-pwdn)
>
> v7:
> [Kieran]
> - Ensure powerdown lines are optional
> - Add a 4ms power-up delay
> - Add max9286_check_config_link() to core
> - Add GPIO chip controller for GPIO0OUT and GPIO1OUT
> - Fix GPIO registration
> - max9286: Split out async registration
> (fixes regulator -EPROBE_DEFERs failures)
> - Collect all V4L2 registrations
> - balance v4l2_async refcnting
> - Rename max9286_v4l2_async_ => max9286_v4l2_notifier_
>
> [Jacopo]
> - Remove redundanct MAXIM_I2C_SPEED macros
> - Move notifiers operations
> - Add delay after reverse channel reconfiguration
> - Move link setup to completion
> - Fix up max9286_check_config_link() implementation
> - Remove redundant dual configuration of reverse channel
>
> v8:
>
> [Kieran]
> - Update the bound_sources mask on unbind
> - Convert probe kzalloc usage to devm_ variant
> - Fix up cleanup path from GPIO PowerDown registration
> - cleanup GPIO device registration fail path
> - Convert to use devm_regulator_get()
> - Fit max9286_parse_dt print on one line
> - Move multi-device workarounds out of upstream driver
> - Remove I2C mod-table
> - Lock format changes
> - Describe pad index usage
> - Remove poc_enabled workaround
> - Rename the max9286_gpio to be more explicit on it's actions.
> - Move max9286_init_format call
> - Rework probe sequence and simplify error paths.
> - Simplify i2c comments
> - Implement Pixelrate control
> - Disable overlap window
>
> [Jacopo]
> - Adapt Kconfig to latest upstream changes
> - Put of node on error
> - Calculate pixel rate
> - Simplify overlap window disablement
>
> v9:
>
> [Kieran]
> - Kconfig: Depend on OF
> - Re-sort addition to Makefile
>
> v10:
>
> [Kieran]
> - Use the same default mbus_fmt everywhere
> - Don't provide GPIO names
> - Fix dev->of_node refcnting
> - Fix whitespace indent
> - Use single sample per pixel
> - Remove redundant DPHY check
> - Remove redundant v4l2_fwnode_endpoint_free call
> - Validate link formats
> ---
> MAINTAINERS | 10 +
> drivers/media/i2c/Kconfig | 13 +
> drivers/media/i2c/Makefile | 1 +
> drivers/media/i2c/max9286.c | 1320 +++++++++++++++++++++++++++++++++++
> 4 files changed, 1344 insertions(+)
> create mode 100644 drivers/media/i2c/max9286.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 791d2a862e41..7534df72033f 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -10274,6 +10274,16 @@ F: Documentation/hwmon/max6697.rst
> 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.yaml
> +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 da11036ad804..0a083407aa3e 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -464,6 +464,19 @@ 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 OF
> + select V4L2_FWNODE
> + select VIDEO_V4L2_SUBDEV_API
> + select MEDIA_CONTROLLER
> + 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 993acab81b2c..c8010d77e1a3 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -118,6 +118,7 @@ obj-$(CONFIG_VIDEO_IMX274) += imx274.o
> obj-$(CONFIG_VIDEO_IMX290) += imx290.o
> obj-$(CONFIG_VIDEO_IMX319) += imx319.o
> obj-$(CONFIG_VIDEO_IMX355) += imx355.o
> +obj-$(CONFIG_VIDEO_MAX9286) += max9286.o
> obj-$(CONFIG_VIDEO_ST_MIPID02) += st-mipid02.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 000000000000..47f280518fdb
> --- /dev/null
> +++ b/drivers/media/i2c/max9286.c
> @@ -0,0 +1,1320 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Maxim MAX9286 GMSL Deserializer Driver
> + *
> + * Copyright (C) 2017-2019 Jacopo Mondi
> + * Copyright (C) 2017-2019 Kieran Bingham
> + * Copyright (C) 2017-2019 Laurent Pinchart
> + * Copyright (C) 2017-2019 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/gpio/consumer.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/i2c.h>
> +#include <linux/i2c-mux.h>
> +#include <linux/module.h>
> +#include <linux/mutex.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 0x0f */
> +#define MAX9286_0X0F_RESERVED BIT(3)
> +/* 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)
> +
> +/*
> + * The sink and source pads are created to match the OF graph port numbers so
> + * that their indexes can be used interchangeably.
> + */
> +#define MAX9286_NUM_GMSL 4
> +#define MAX9286_N_SINKS 4
> +#define MAX9286_N_PADS 5
> +#define MAX9286_SRC_PAD 4
> +
> +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 gpio_desc *gpiod_pwdn;
> + struct v4l2_subdev sd;
> + struct media_pad pads[MAX9286_N_PADS];
> + struct regulator *regulator;
> +
> + struct gpio_chip gpio;
> + u8 gpio_state;
> +
> + struct i2c_mux_core *mux;
> + unsigned int mux_channel;
> + bool mux_open;
> +
> + struct v4l2_ctrl_handler ctrls;
> + struct v4l2_ctrl *pixelrate;
> +
> + struct v4l2_mbus_framefmt fmt[MAX9286_N_SINKS];
> +
> + /* Protects controls and fmt structures */
> + struct mutex mutex;
> +
> + unsigned int nsources;
> + unsigned int source_mask;
> + unsigned int route_mask;
> + unsigned int bound_sources;
> + 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(priv, source) \
> + for ((source) = NULL; ((source) = next_source((priv), (source))); )
> +
> +#define to_index(priv, source) ((source) - &(priv)->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 void max9286_i2c_mux_configure(struct max9286_priv *priv, u8 conf)
> +{
> + max9286_write(priv, 0x0a, conf);
> +
> + /*
> + * We must sleep after any change to the forward or reverse channel
> + * configuration.
> + */
> + usleep_range(3000, 5000);
> +}
> +
> +static void max9286_i2c_mux_open(struct max9286_priv *priv)
> +{
> + /* Open all channels on the MAX9286 */
> + max9286_i2c_mux_configure(priv, 0xff);
> +
> + priv->mux_open = true;
> +}
> +
> +static void max9286_i2c_mux_close(struct max9286_priv *priv)
> +{
> + /*
> + * 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 max9286_i2c_mux_select() call.
> + */
> + max9286_i2c_mux_configure(priv, 0x00);
> +
> + priv->mux_open = false;
> + priv->mux_channel = -1;
> +}
> +
> +static int max9286_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
> +{
> + struct max9286_priv *priv = i2c_mux_priv(muxc);
> +
> + /* Channel select is disabled when configured in the opened state. */
> + if (priv->mux_open)
> + return 0;
> +
> + if (priv->mux_channel == chan)
> + return 0;
> +
> + priv->mux_channel = chan;
> +
> + max9286_i2c_mux_configure(priv,
> + MAX9286_FWDCCEN(chan) |
> + MAX9286_REVCCEN(chan));
> +
> + 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 |
> + MAX9286_I2CMSTBT_105KBPS;
> +
> + if (localack)
> + config |= MAX9286_I2CLOCACK;
> +
> + max9286_write(priv, 0x34, config);
> + usleep_range(3000, 5000);
> +}
> +
> +/*
> + * 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;
> +}
> +
> +/*
> + * max9286_check_config_link() - Detect and wait for configuration links
> + *
> + * Determine if the configuration channel is up and settled for a link.
> + *
> + * Returns 0 for success, -EIO for errors.
> + */
> +static int max9286_check_config_link(struct max9286_priv *priv,
> + unsigned int source_mask)
> +{
> + unsigned int conflink_mask = (source_mask & 0x0f) << 4;
> + unsigned int i;
> + int ret;
> +
> + /*
> + * Make sure requested configuration links are detected.
> + * The delay is not characterized in the chip manual: wait up
> + * to 5 milliseconds.
> + */
> + for (i = 0; i < 10; i++) {
> + ret = max9286_read(priv, 0x49) & 0xf0;
> + if (ret < 0)
> + return -EIO;
> +
> + if (ret == conflink_mask)
> + break;
> +
> + usleep_range(350, 500);
> + }
> +
> + if (ret != conflink_mask) {
> + dev_err(&priv->client->dev,
> + "Unable to detect configuration links: 0x%02x expected 0x%02x\n",
> + ret, conflink_mask);
> + return -EIO;
> + }
> +
> + dev_info(&priv->client->dev,
> + "Successfully detected configuration links after %u loops: 0x%02x\n",
> + i, conflink_mask);
> +
> + return 0;
> +}
> +
> +/* -----------------------------------------------------------------------------
> + * V4L2 Subdev
> + */
> +
> +static int max9286_set_pixelrate(struct max9286_priv *priv)
> +{
> + struct max9286_source *source = NULL;
> + u64 pixelrate = 0;
> +
> + for_each_source(priv, source) {
> + struct v4l2_ctrl *ctrl;
> + u64 source_rate = 0;
> +
> + /* Pixel rate is mandatory to be reported by sources. */
> + ctrl = v4l2_ctrl_find(source->sd->ctrl_handler,
> + V4L2_CID_PIXEL_RATE);
> + if (!ctrl) {
> + pixelrate = 0;
> + break;
> + }
> +
> + /* All source must report the same pixel rate. */
> + source_rate = v4l2_ctrl_g_ctrl_int64(ctrl);
> + if (!pixelrate) {
> + pixelrate = source_rate;
> + } else if (pixelrate != source_rate) {
> + dev_err(&priv->client->dev,
> + "Unable to calculate pixel rate\n");
> + return -EINVAL;
> + }
> + }
> +
> + if (!pixelrate) {
> + dev_err(&priv->client->dev,
> + "No pixel rate control available in sources\n");
> + return -EINVAL;
> + }
> +
> + /*
> + * The CSI-2 transmitter pixel rate is the single source rate multiplied
> + * by the number of available sources.
> + */
> + return v4l2_ctrl_s_ctrl_int64(priv->pixelrate,
> + pixelrate * priv->nsources);
> +}
> +
> +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;
> + }
> +
> + priv->bound_sources |= BIT(index);
> + 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);
> +
> + /*
> + * We can only register v4l2_async_notifiers, which do not provide a
> + * means to register a complete callback. bound_sources allows us to
> + * identify when all remote serializers have completed their probe.
> + */
> + if (priv->bound_sources != priv->source_mask)
> + return 0;
> +
> + /*
> + * All enabled sources have probed and enabled their reverse control
> + * channels:
> + *
> + * - Verify all configuration links are properly detected
> + * - Disable auto-ack as communication on the control channel are now
> + * stable.
> + */
> + max9286_check_config_link(priv, priv->source_mask);
> +
> + /*
> + * Re-configure I2C with local acknowledge disabled after cameras have
> + * probed.
> + */
> + max9286_configure_i2c(priv, false);
> +
> + return max9286_set_pixelrate(priv);
> +}
> +
> +static void max9286_notify_unbind(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);
> +
> + source->sd = NULL;
> + priv->bound_sources &= ~BIT(index);
> +}
> +
> +static const struct v4l2_async_notifier_operations max9286_notify_ops = {
> + .bound = max9286_notify_bound,
> + .unbind = max9286_notify_unbind,
> +};
> +
> +static int max9286_v4l2_notifier_register(struct max9286_priv *priv)
> +{
> + struct device *dev = &priv->client->dev;
> + struct max9286_source *source = NULL;
> + int ret;
> +
> + if (!priv->nsources)
> + return 0;
> +
> + v4l2_async_notifier_init(&priv->notifier);
> +
> + for_each_source(priv, source) {
> + unsigned int i = to_index(priv, source);
> +
> + 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) {
> + dev_err(dev, "Failed to add subdev for source %d", i);
> + v4l2_async_notifier_cleanup(&priv->notifier);
> + return ret;
> + }
> +
> + /*
> + * Balance the reference counting handled through
> + * v4l2_async_notifier_cleanup()
> + */
> + fwnode_handle_get(source->fwnode);
> + }
> +
> + priv->notifier.ops = &max9286_notify_ops;
> +
> + ret = v4l2_async_subdev_notifier_register(&priv->sd, &priv->notifier);
> + if (ret) {
> + dev_err(dev, "Failed to register subdev_notifier");
> + v4l2_async_notifier_cleanup(&priv->notifier);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static void max9286_v4l2_notifier_unregister(struct max9286_priv *priv)
> +{
> + if (!priv->nsources)
> + return;
> +
> + v4l2_async_notifier_unregister(&priv->notifier);
> + v4l2_async_notifier_cleanup(&priv->notifier);
> +}
> +
> +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) {
> + /*
> + * The frame sync between cameras is transmitted across the
> + * reverse channel as GPIO. We must open all channels while
> + * streaming to allow this synchronisation signal to be shared.
> + */
> + max9286_i2c_mux_open(priv);
> +
> + /* 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 practical experience at least 8 are required. Give
> + * 12 complete frames time (~400ms at 30 fps) to achieve frame
> + * locking before returning error.
> + */
> + for (i = 0; i < 40; 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 -EXDEV; /* Invalid cross-device link */
> + }
> +
> + /*
> + * 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);
> +
> + max9286_i2c_mux_close(priv);
> + }
> +
> + 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_1X16;
> +
> + 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_1X16:
> + case MEDIA_BUS_FMT_VYUY8_1X16:
> + case MEDIA_BUS_FMT_YUYV8_1X16:
> + case MEDIA_BUS_FMT_YVYU8_1X16:
> + break;
> + default:
> + format->format.code = MEDIA_BUS_FMT_UYVY8_1X16;
> + break;
> + }
> +
> + cfg_fmt = max9286_get_pad_format(priv, cfg, format->pad, format->which);
> + if (!cfg_fmt)
> + return -EINVAL;
> +
> + mutex_lock(&priv->mutex);
> + *cfg_fmt = format->format;
> + mutex_unlock(&priv->mutex);
> +
> + 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;
> + unsigned int pad = format->pad;
> +
> + /*
> + * Multiplexed Stream Support: Support link validation by returning the
> + * format of the first bound link. All links must have the same format,
> + * as we do not support mixing and matching of cameras connected to the
> + * max9286.
> + */
> + if (pad == MAX9286_SRC_PAD)
> + pad = __ffs(priv->bound_sources);
> +
> + cfg_fmt = max9286_get_pad_format(priv, cfg, pad, format->which);
> + if (!cfg_fmt)
> + return -EINVAL;
> +
> + mutex_lock(&priv->mutex);
> + format->format = *cfg_fmt;
> + mutex_unlock(&priv->mutex);
> +
> + 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_1X16;
> + 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,
> +};
> +
> +static int max9286_s_ctrl(struct v4l2_ctrl *ctrl)
> +{
> + switch (ctrl->id) {
> + case V4L2_CID_PIXEL_RATE:
> + return 0;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static const struct v4l2_ctrl_ops max9286_ctrl_ops = {
> + .s_ctrl = max9286_s_ctrl,
> +};
> +
> +static int max9286_v4l2_register(struct max9286_priv *priv)
> +{
> + struct device *dev = &priv->client->dev;
> + struct fwnode_handle *ep;
> + int ret;
> + int i;
> +
> + /* Register v4l2 async notifiers for connected Camera subdevices */
> + ret = max9286_v4l2_notifier_register(priv);
> + if (ret) {
> + dev_err(dev, "Unable to register V4L2 async notifiers\n");
> + return ret;
> + }
> +
> + /* Configure V4L2 for the MAX9286 itself */
> +
> + for (i = 0; i < MAX9286_N_SINKS; i++)
> + max9286_init_format(&priv->fmt[i]);
> +
> + v4l2_i2c_subdev_init(&priv->sd, priv->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);
> + priv->pixelrate = v4l2_ctrl_new_std(&priv->ctrls,
> + &max9286_ctrl_ops,
> + V4L2_CID_PIXEL_RATE,
> + 1, INT_MAX, 1, 50000000);
> +
> + priv->sd.ctrl_handler = &priv->ctrls;
> + ret = priv->ctrls.error;
> + if (ret)
> + goto err_async;
> +
> + 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_async;
> +
> + 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_async;
> + }
> + 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;
> + }
> +
> + return 0;
> +
> +err_put_node:
> + fwnode_handle_put(ep);
> +err_async:
> + max9286_v4l2_notifier_unregister(priv);
> +
> + return ret;
> +}
> +
> +static void max9286_v4l2_unregister(struct max9286_priv *priv)
> +{
> + fwnode_handle_put(priv->sd.fwnode);
> + v4l2_async_unregister_subdev(&priv->sd);
> + max9286_v4l2_notifier_unregister(priv);
> +}
> +
> +/* -----------------------------------------------------------------------------
> + * 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);
> + usleep_range(2000, 2500);
> +
> + /*
> + * 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 according 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);
> +
> + /*
> + * The overlap window seems to provide additional validation by tracking
> + * the delay between vsync and frame sync, generating an error if the
> + * delay is bigger than the programmed window, though it's not yet clear
> + * what value should be set.
> + *
> + * As it's an optional value and can be disabled, we do so by setting
> + * a 0 overlap value.
> + */
> + max9286_write(priv, 0x63, 0);
> + max9286_write(priv, 0x64, 0);
> +
> + /*
> + * Wait for 2ms to allow the link to resynchronize after the
> + * configuration change.
> + */
> + usleep_range(2000, 5000);
> +
> + return 0;
> +}
> +
> +static void max9286_gpio_set(struct gpio_chip *chip,
> + unsigned int offset, int value)
> +{
> + struct max9286_priv *priv = gpiochip_get_data(chip);
> +
> + if (value)
> + priv->gpio_state |= BIT(offset);
> + else
> + priv->gpio_state &= ~BIT(offset);
> +
> + max9286_write(priv, 0x0f, MAX9286_0X0F_RESERVED | priv->gpio_state);
> +}
> +
> +static int max9286_gpio_get(struct gpio_chip *chip, unsigned int offset)
> +{
> + struct max9286_priv *priv = gpiochip_get_data(chip);
> +
> + return priv->gpio_state & BIT(offset);
> +}
> +
> +static int max9286_register_gpio(struct max9286_priv *priv)
> +{
> + struct device *dev = &priv->client->dev;
> + struct gpio_chip *gpio = &priv->gpio;
> + int ret;
> +
> + /* Configure the GPIO */
> + gpio->label = dev_name(dev);
> + gpio->parent = dev;
> + gpio->owner = THIS_MODULE;
> + gpio->of_node = dev->of_node;
> + gpio->ngpio = 2;
> + gpio->base = -1;
> + gpio->set = max9286_gpio_set;
> + gpio->get = max9286_gpio_get;
> + gpio->can_sleep = true;
> +
> + /* GPIO values default to high */
> + priv->gpio_state = BIT(0) | BIT(1);
> +
> + ret = devm_gpiochip_add_data(dev, gpio, priv);
> + if (ret)
> + dev_err(dev, "Unable to create gpio_chip\n");
> +
> + return ret;
> +}
> +
> +static int max9286_init(struct device *dev)
> +{
> + struct max9286_priv *priv;
> + struct i2c_client *client;
> + int ret;
> +
> + 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;
> + }
> +
> + ret = max9286_setup(priv);
> + if (ret) {
> + dev_err(dev, "Unable to setup max9286\n");
> + goto err_regulator;
> + }
> +
> + /*
> + * Register all V4L2 interactions for the MAX9286 and notifiers for
> + * any subdevices connected.
> + */
> + ret = max9286_v4l2_register(priv);
> + if (ret) {
> + dev_err(dev, "Failed to register with V4L2\n");
> + goto err_regulator;
> + }
> +
> + ret = max9286_i2c_mux_init(priv);
> + if (ret) {
> + dev_err(dev, "Unable to initialize I2C multiplexer\n");
> + goto err_v4l2_register;
> + }
> +
> + /* Leave the mux channels disabled until they are selected. */
> + max9286_i2c_mux_close(priv);
> +
> + return 0;
> +
> +err_v4l2_register:
> + max9286_v4l2_unregister(priv);
> +err_regulator:
> + regulator_disable(priv->regulator);
> +
> + return ret;
> +}
> +
> +static void max9286_cleanup_dt(struct max9286_priv *priv)
> +{
> + struct max9286_source *source;
> +
> + 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 *i2c_mux;
> + struct device_node *node = NULL;
> + unsigned int i2c_mux_mask = 0;
> +
> + /* Balance the of_node_put() performed by of_find_node_by_name(). */
> + of_node_get(dev->of_node);
> + i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
> + if (!i2c_mux) {
> + dev_err(dev, "Failed to find i2c-mux node\n");
> + return -EINVAL;
> + }
> +
> + /* Identify which i2c-mux channels are enabled */
> + for_each_child_of_node(i2c_mux, node) {
> + u32 id = 0;
> +
> + of_property_read_u32(node, "reg", &id);
> + if (id >= MAX9286_NUM_GMSL)
> + continue;
> +
> + if (!of_device_is_available(node)) {
> + dev_dbg(dev, "Skipping disabled I2C bus port %u\n", id);
> + continue;
> + }
> +
> + i2c_mux_mask |= BIT(id);
> + }
> + of_node_put(node);
> + of_node_put(i2c_mux);
> +
> + /* Parse the endpoints */
> + for_each_endpoint_of_node(dev->of_node, node) {
> + struct max9286_source *source;
> + struct of_endpoint ep;
> +
> + of_graph_parse_endpoint(node, &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 = V4L2_MBUS_CSI2_DPHY
> + };
> + int ret;
> +
> + ret = v4l2_fwnode_endpoint_parse(
> + of_fwnode_handle(node), &vep);
> + if (ret) {
> + of_node_put(node);
> + return ret;
> + }
> +
> + priv->csi2_data_lanes =
> + vep.bus.mipi_csi2.num_data_lanes;
> +
> + continue;
> + }
> +
> + /* Skip if the corresponding GMSL link is unavailable. */
> + if (!(i2c_mux_mask & BIT(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(node));
> + if (!source->fwnode) {
> + dev_err(dev,
> + "Endpoint %pOF has no remote endpoint connection\n",
> + ep.local_node);
> +
> + continue;
> + }
> +
> + priv->source_mask |= BIT(ep.port);
> + priv->nsources++;
> + }
> + of_node_put(node);
> +
> + priv->route_mask = priv->source_mask;
> +
> + return 0;
> +}
> +
> +static int max9286_probe(struct i2c_client *client)
> +{
> + struct max9286_priv *priv;
> + int ret;
> +
> + priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + mutex_init(&priv->mutex);
> +
> + priv->client = client;
> + i2c_set_clientdata(client, priv);
> +
> + priv->gpiod_pwdn = devm_gpiod_get_optional(&client->dev, "enable",
> + GPIOD_OUT_HIGH);
> + if (IS_ERR(priv->gpiod_pwdn))
> + return PTR_ERR(priv->gpiod_pwdn);
> +
> + gpiod_set_consumer_name(priv->gpiod_pwdn, "max9286-pwdn");
> + gpiod_set_value_cansleep(priv->gpiod_pwdn, 1);
> +
> + /* Wait at least 4ms before the I2C lines latch to the address */
> + if (priv->gpiod_pwdn)
> + usleep_range(4000, 5000);
> +
> + /*
> + * The MAX9286 starts by default with all ports enabled, we disable all
> + * ports early to ensure that all channels are disabled if we error out
> + * and keep the bus consistent.
> + */
> + max9286_i2c_mux_close(priv);
> +
> + /*
> + * The MAX9286 initialises with auto-acknowledge enabled by default.
> + * This can be invasive to other transactions on the same bus, so
> + * disable it early. It will be enabled only as and when needed.
> + */
> + max9286_configure_i2c(priv, false);
> +
> + ret = max9286_register_gpio(priv);
> + if (ret)
> + goto err_powerdown;
> +
> + priv->regulator = devm_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_powerdown;
> + }
> +
> + ret = max9286_parse_dt(priv);
> + if (ret)
> + goto err_powerdown;
> +
> + ret = max9286_init(&client->dev);
> + if (ret < 0)
> + goto err_cleanup_dt;
> +
> + return 0;
> +
> +err_cleanup_dt:
> + max9286_cleanup_dt(priv);
> +err_powerdown:
> + gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
> +
> + return ret;
> +}
> +
> +static int max9286_remove(struct i2c_client *client)
> +{
> + struct max9286_priv *priv = i2c_get_clientdata(client);
> +
> + i2c_mux_del_adapters(priv->mux);
> +
> + max9286_v4l2_unregister(priv);
> +
> + regulator_disable(priv->regulator);
> +
> + gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
> +
> + max9286_cleanup_dt(priv);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id max9286_dt_ids[] = {
> + { .compatible = "maxim,max9286" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, max9286_dt_ids);
> +
> +static struct i2c_driver max9286_i2c_driver = {
> + .driver = {
> + .name = "max9286",
> + .of_match_table = of_match_ptr(max9286_dt_ids),
> + },
> + .probe_new = max9286_probe,
> + .remove = max9286_remove,
> +};
> +
> +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");
> --
> 2.25.1
>

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