// 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* 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_RAW12 (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_CSI_IMAGE_TYP BIT(7) #define MAX9286_VC(n) ((n) << 5) #define MAX9286_VCTYPE BIT(4) #define MAX9286_CSIOUTEN BIT(3) #define MAX9286_SWP_ENDIAN BIT(2) #define MAX9286_EN_CCBSYB_CLK_STR BIT(1) #define MAX9286_EN_GPI_CCBSYB BIT(0) /* Register 0x1b */ #define MAX9286_SWITCHIN(n) (1 << ((n) + 4)) #define MAX9286_ENEQ(n) (1 << (n)) /* Register 0x1c */ #define MAX9286_HIGHIMM(n) BIT((n) + 4) #define MAX9286_I2CSEL BIT(2) #define MAX9286_HIBW BIT(1) #define MAX9286_BWS BIT(0) /* 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) #define MAX9286_REV_AMP_HIGH 170 /* 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_format_info { u32 code; u8 datatype; }; struct max9286_i2c_speed { u32 rate; u8 mstbt; }; struct max9286_source { struct v4l2_subdev *sd; struct fwnode_handle *fwnode; struct regulator *regulator; }; struct max9286_asd { struct v4l2_async_connection base; struct max9286_source *source; }; static inline struct max9286_asd * to_max9286_asd(struct v4l2_async_connection *asd) { return container_of(asd, struct max9286_asd, base); } 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; /* The initial reverse control channel amplitude. */ u32 init_rev_chan_mv; u32 rev_chan_mv; u8 i2c_mstbt; u32 bus_width; bool use_gpio_poc; u32 gpio_poc[2]; struct v4l2_ctrl_handler ctrls; struct v4l2_ctrl *pixelrate_ctrl; unsigned int pixelrate; struct v4l2_mbus_framefmt fmt[MAX9286_N_SINKS]; struct v4l2_fract interval; /* 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); } static const struct max9286_format_info max9286_formats[] = { { .code = MEDIA_BUS_FMT_UYVY8_1X16, .datatype = MAX9286_DATATYPE_YUV422_8BIT, }, { .code = MEDIA_BUS_FMT_VYUY8_1X16, .datatype = MAX9286_DATATYPE_YUV422_8BIT, }, { .code = MEDIA_BUS_FMT_YUYV8_1X16, .datatype = MAX9286_DATATYPE_YUV422_8BIT, }, { .code = MEDIA_BUS_FMT_YVYU8_1X16, .datatype = MAX9286_DATATYPE_YUV422_8BIT, }, { .code = MEDIA_BUS_FMT_SBGGR12_1X12, .datatype = MAX9286_DATATYPE_RAW12, }, { .code = MEDIA_BUS_FMT_SGBRG12_1X12, .datatype = MAX9286_DATATYPE_RAW12, }, { .code = MEDIA_BUS_FMT_SGRBG12_1X12, .datatype = MAX9286_DATATYPE_RAW12, }, { .code = MEDIA_BUS_FMT_SRGGB12_1X12, .datatype = MAX9286_DATATYPE_RAW12, }, }; static const struct max9286_i2c_speed max9286_i2c_speeds[] = { { .rate = 8470, .mstbt = MAX9286_I2CMSTBT_8KBPS }, { .rate = 28300, .mstbt = MAX9286_I2CMSTBT_28KBPS }, { .rate = 84700, .mstbt = MAX9286_I2CMSTBT_84KBPS }, { .rate = 105000, .mstbt = MAX9286_I2CMSTBT_105KBPS }, { .rate = 173000, .mstbt = MAX9286_I2CMSTBT_173KBPS }, { .rate = 339000, .mstbt = MAX9286_I2CMSTBT_339KBPS }, { .rate = 533000, .mstbt = MAX9286_I2CMSTBT_533KBPS }, { .rate = 837000, .mstbt = MAX9286_I2CMSTBT_837KBPS }, }; /* ----------------------------------------------------------------------------- * 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 | priv->i2c_mstbt; if (localack) config |= MAX9286_I2CLOCACK; max9286_write(priv, 0x34, config); usleep_range(3000, 5000); } static void max9286_reverse_channel_setup(struct max9286_priv *priv, unsigned int chan_amplitude) { u8 chan_config; if (priv->rev_chan_mv == chan_amplitude) return; priv->rev_chan_mv = chan_amplitude; /* Reverse channel transmission time: default to 1. */ chan_config = MAX9286_REV_TRF(1); /* * Reverse channel setup. * * - Enable custom reverse channel configuration (through register 0x3f) * and set the first pulse length to 35 clock cycles. * - Adjust reverse channel amplitude: values > 130 are programmed * using the additional +100mV REV_AMP_X boost flag */ max9286_write(priv, 0x3f, MAX9286_EN_REV_CFG | MAX9286_REV_FLEN(35)); if (chan_amplitude > 100) { /* It is not possible to express values (100 < x < 130) */ chan_amplitude = max(30U, chan_amplitude - 100); chan_config |= MAX9286_REV_AMP_X; } max9286_write(priv, 0x3b, chan_config | MAX9286_REV_AMP(chan_amplitude)); usleep_range(2000, 2500); } /* * 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); if (ret < 0) return -EIO; ret &= 0xf0; 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; } static void max9286_set_video_format(struct max9286_priv *priv, const struct v4l2_mbus_framefmt *format) { const struct max9286_format_info *info = NULL; unsigned int i; for (i = 0; i < ARRAY_SIZE(max9286_formats); ++i) { if (max9286_formats[i].code == format->code) { info = &max9286_formats[i]; break; } } if (WARN_ON(!info)) return; /* * Video format setup: disable CSI output, set VC according to Link * number, enable I2C clock stretching when CCBSY is low, enable CCBSY * in external GPI-to-GPO mode. */ max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_EN_CCBSYB_CLK_STR | MAX9286_EN_GPI_CCBSYB); /* Enable CSI-2 Lane D0-D3 only, DBL mode. */ max9286_write(priv, 0x12, MAX9286_CSIDBL | MAX9286_DBL | MAX9286_CSILANECNT(priv->csi2_data_lanes) | info->datatype); /* * Enable HS/VS encoding, use HS as line valid source, use D14/15 for * HS/VS, invert VS. */ max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_DESEL | MAX9286_INVVS | MAX9286_HVSRC_D14); } static void max9286_set_fsync_period(struct max9286_priv *priv) { u32 fsync; if (!priv->interval.numerator || !priv->interval.denominator) { /* * Special case, a null interval enables automatic FRAMESYNC * mode. FRAMESYNC is taken from the slowest link. */ max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ | MAX9286_FSYNCMETH_AUTO); return; } /* * Manual FRAMESYNC * * The FRAMESYNC generator is configured with a period expressed as a * number of PCLK periods. */ fsync = div_u64((u64)priv->pixelrate * priv->interval.numerator, priv->interval.denominator); dev_dbg(&priv->client->dev, "fsync period %u (pclk %u)\n", fsync, priv->pixelrate); max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_OUT | MAX9286_FSYNCMETH_MANUAL); max9286_write(priv, 0x06, (fsync >> 0) & 0xff); max9286_write(priv, 0x07, (fsync >> 8) & 0xff); max9286_write(priv, 0x08, (fsync >> 16) & 0xff); } /* ----------------------------------------------------------------------------- * 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; } priv->pixelrate = pixelrate; /* * 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_ctrl, pixelrate * priv->nsources); } static int max9286_notify_bound(struct v4l2_async_notifier *notifier, struct v4l2_subdev *subdev, struct v4l2_async_connection *asd) { struct max9286_priv *priv = sd_to_max9286(notifier->sd); struct max9286_source *source = to_max9286_asd(asd)->source; 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); /* * As we register a subdev notifiers we won't get a .complete() callback * here, so we have to use bound_sources to identify when all remote * serializers have probed. */ if (priv->bound_sources != priv->source_mask) return 0; /* * All enabled sources have probed and enabled their reverse control * channels: * * - Increase the reverse channel amplitude to compensate for the * remote ends high threshold * - Verify all configuration links are properly detected * - Disable auto-ack as communication on the control channel are now * stable. */ max9286_reverse_channel_setup(priv, MAX9286_REV_AMP_HIGH); max9286_check_config_link(priv, priv->source_mask); 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_connection *asd) { struct max9286_priv *priv = sd_to_max9286(notifier->sd); struct max9286_source *source = to_max9286_asd(asd)->source; 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_subdev_nf_init(&priv->notifier, &priv->sd); for_each_source(priv, source) { unsigned int i = to_index(priv, source); struct max9286_asd *mas; mas = v4l2_async_nf_add_fwnode(&priv->notifier, source->fwnode, struct max9286_asd); if (IS_ERR(mas)) { dev_err(dev, "Failed to add subdev for source %u: %ld", i, PTR_ERR(mas)); v4l2_async_nf_cleanup(&priv->notifier); return PTR_ERR(mas); } mas->source = source; } priv->notifier.ops = &max9286_notify_ops; ret = v4l2_async_nf_register(&priv->notifier); if (ret) { dev_err(dev, "Failed to register subdev_notifier"); v4l2_async_nf_cleanup(&priv->notifier); return ret; } return 0; } static void max9286_v4l2_notifier_unregister(struct max9286_priv *priv) { if (!priv->nsources) return; v4l2_async_nf_unregister(&priv->notifier); v4l2_async_nf_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) { const struct v4l2_mbus_framefmt *format; /* * Get the format from the first used sink pad, as all sink * formats must be identical. */ format = &priv->fmt[__ffs(priv->bound_sources)]; max9286_set_video_format(priv, format); max9286_set_fsync_period(priv); /* * 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 */ } /* * Configure the CSI-2 output to line interleaved mode (W x (N * x H), as opposed to the (N x W) x H mode that outputs the * images stitched side-by-side) and enable it. */ max9286_write(priv, 0x15, MAX9286_CSI_IMAGE_TYP | MAX9286_VCTYPE | MAX9286_CSIOUTEN | MAX9286_EN_CCBSYB_CLK_STR | MAX9286_EN_GPI_CCBSYB); } else { max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_EN_CCBSYB_CLK_STR | MAX9286_EN_GPI_CCBSYB); /* 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_get_frame_interval(struct v4l2_subdev *sd, struct v4l2_subdev_state *sd_state, struct v4l2_subdev_frame_interval *interval) { struct max9286_priv *priv = sd_to_max9286(sd); /* * FIXME: Implement support for V4L2_SUBDEV_FORMAT_TRY, using the V4L2 * subdev active state API. */ if (interval->which != V4L2_SUBDEV_FORMAT_ACTIVE) return -EINVAL; if (interval->pad != MAX9286_SRC_PAD) return -EINVAL; interval->interval = priv->interval; return 0; } static int max9286_set_frame_interval(struct v4l2_subdev *sd, struct v4l2_subdev_state *sd_state, struct v4l2_subdev_frame_interval *interval) { struct max9286_priv *priv = sd_to_max9286(sd); /* * FIXME: Implement support for V4L2_SUBDEV_FORMAT_TRY, using the V4L2 * subdev active state API. */ if (interval->which != V4L2_SUBDEV_FORMAT_ACTIVE) return -EINVAL; if (interval->pad != MAX9286_SRC_PAD) return -EINVAL; priv->interval = interval->interval; return 0; } static int max9286_enum_mbus_code(struct v4l2_subdev *sd, struct v4l2_subdev_state *sd_state, 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_state *sd_state, unsigned int pad, u32 which) { switch (which) { case V4L2_SUBDEV_FORMAT_TRY: return v4l2_subdev_state_get_format(sd_state, 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_state *sd_state, struct v4l2_subdev_format *format) { struct max9286_priv *priv = sd_to_max9286(sd); struct v4l2_mbus_framefmt *cfg_fmt; unsigned int i; if (format->pad == MAX9286_SRC_PAD) return -EINVAL; /* Validate the format. */ for (i = 0; i < ARRAY_SIZE(max9286_formats); ++i) { if (max9286_formats[i].code == format->format.code) break; } if (i == ARRAY_SIZE(max9286_formats)) format->format.code = max9286_formats[0].code; cfg_fmt = max9286_get_pad_format(priv, sd_state, 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_state *sd_state, 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, sd_state, 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, .get_frame_interval = max9286_get_frame_interval, .set_frame_interval = max9286_set_frame_interval, }; static const struct v4l2_subdev_ops max9286_subdev_ops = { .video = &max9286_video_ops, .pad = &max9286_pad_ops, }; static const struct v4l2_mbus_framefmt max9286_default_format = { .width = 1280, .height = 800, .code = MEDIA_BUS_FMT_UYVY8_1X16, .colorspace = V4L2_COLORSPACE_SRGB, .field = V4L2_FIELD_NONE, .ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT, .quantization = V4L2_QUANTIZATION_DEFAULT, .xfer_func = V4L2_XFER_FUNC_DEFAULT, }; static void max9286_init_format(struct v4l2_mbus_framefmt *fmt) { *fmt = max9286_default_format; } 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_state_get_format(fh->state, i); max9286_init_format(format); } return 0; } static const struct v4l2_subdev_internal_ops max9286_subdev_internal_ops = { .open = max9286_open, }; static const struct media_entity_operations max9286_media_ops = { .link_validate = v4l2_subdev_link_validate }; 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; 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_ctrl = 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->sd.entity.ops = &max9286_media_ops; 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; ret = v4l2_async_register_subdev(&priv->sd); if (ret < 0) { dev_err(dev, "Unable to register subdevice\n"); goto err_async; } return 0; err_async: v4l2_ctrl_handler_free(&priv->ctrls); max9286_v4l2_notifier_unregister(priv); return ret; } static void max9286_v4l2_unregister(struct max9286_priv *priv) { v4l2_ctrl_handler_free(&priv->ctrls); 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 */ }; int cfg; /* * 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); max9286_reverse_channel_setup(priv, priv->init_rev_chan_mv); /* * 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)); max9286_set_video_format(priv, &max9286_default_format); max9286_set_fsync_period(priv); cfg = max9286_read(priv, 0x1c); if (cfg < 0) return cfg; dev_dbg(&priv->client->dev, "power-up config: %s immunity, %u-bit bus\n", cfg & MAX9286_HIGHIMM(0) ? "high" : "legacy", cfg & MAX9286_BWS ? 32 : cfg & MAX9286_HIBW ? 27 : 24); if (priv->bus_width) { cfg &= ~(MAX9286_HIBW | MAX9286_BWS); if (priv->bus_width == 27) cfg |= MAX9286_HIBW; else if (priv->bus_width == 32) cfg |= MAX9286_BWS; max9286_write(priv, 0x1c, cfg); } /* * 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 int max9286_gpio_set(struct max9286_priv *priv, unsigned int offset, int value) { if (value) priv->gpio_state |= BIT(offset); else priv->gpio_state &= ~BIT(offset); return max9286_write(priv, 0x0f, MAX9286_0X0F_RESERVED | priv->gpio_state); } static void max9286_gpiochip_set(struct gpio_chip *chip, unsigned int offset, int value) { struct max9286_priv *priv = gpiochip_get_data(chip); max9286_gpio_set(priv, offset, value); } static int max9286_gpiochip_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->ngpio = 2; gpio->base = -1; gpio->set = max9286_gpiochip_set; gpio->get = max9286_gpiochip_get; gpio->can_sleep = true; ret = devm_gpiochip_add_data(dev, gpio, priv); if (ret) dev_err(dev, "Unable to create gpio_chip\n"); return ret; } static int max9286_parse_gpios(struct max9286_priv *priv) { struct device *dev = &priv->client->dev; int ret; /* * Parse the "gpio-poc" vendor property. If the property is not * specified the camera power is controlled by a regulator. */ ret = of_property_read_u32_array(dev->of_node, "maxim,gpio-poc", priv->gpio_poc, 2); if (ret == -EINVAL) { /* * If gpio lines are not used for the camera power, register * a gpio controller for consumers. */ return max9286_register_gpio(priv); } /* If the property is specified make sure it is well formed. */ if (ret || priv->gpio_poc[0] > 1 || (priv->gpio_poc[1] != GPIO_ACTIVE_HIGH && priv->gpio_poc[1] != GPIO_ACTIVE_LOW)) { dev_err(dev, "Invalid 'gpio-poc' property\n"); return -EINVAL; } priv->use_gpio_poc = true; return 0; } static int max9286_poc_power_on(struct max9286_priv *priv) { struct max9286_source *source; unsigned int enabled = 0; int ret; /* Enable the global regulator if available. */ if (priv->regulator) return regulator_enable(priv->regulator); if (priv->use_gpio_poc) return max9286_gpio_set(priv, priv->gpio_poc[0], !priv->gpio_poc[1]); /* Otherwise use the per-port regulators. */ for_each_source(priv, source) { ret = regulator_enable(source->regulator); if (ret < 0) goto error; enabled |= BIT(to_index(priv, source)); } return 0; error: for_each_source(priv, source) { if (enabled & BIT(to_index(priv, source))) regulator_disable(source->regulator); } return ret; } static int max9286_poc_power_off(struct max9286_priv *priv) { struct max9286_source *source; int ret = 0; if (priv->regulator) return regulator_disable(priv->regulator); if (priv->use_gpio_poc) return max9286_gpio_set(priv, priv->gpio_poc[0], priv->gpio_poc[1]); for_each_source(priv, source) { int err; err = regulator_disable(source->regulator); if (!ret) ret = err; } return ret; } static int max9286_poc_enable(struct max9286_priv *priv, bool enable) { int ret; if (enable) ret = max9286_poc_power_on(priv); else ret = max9286_poc_power_off(priv); if (ret < 0) dev_err(&priv->client->dev, "Unable to turn power %s\n", enable ? "on" : "off"); return ret; } static int max9286_init(struct max9286_priv *priv) { struct i2c_client *client = priv->client; int ret; ret = max9286_poc_enable(priv, true); if (ret) return ret; ret = max9286_setup(priv); if (ret) { dev_err(&client->dev, "Unable to setup max9286\n"); goto err_poc_disable; } /* * Register all V4L2 interactions for the MAX9286 and notifiers for * any subdevices connected. */ ret = max9286_v4l2_register(priv); if (ret) { dev_err(&client->dev, "Failed to register with V4L2\n"); goto err_poc_disable; } ret = max9286_i2c_mux_init(priv); if (ret) { dev_err(&client->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_poc_disable: max9286_poc_enable(priv, false); 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; u32 reverse_channel_microvolt; u32 i2c_clk_freq = 105000; unsigned int i; /* 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(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_property_read_u32(dev->of_node, "maxim,bus-width", &priv->bus_width); switch (priv->bus_width) { case 0: /* * The property isn't specified in the device tree, the driver * will keep the default value selected by the BWS pin. */ case 24: case 27: case 32: break; default: dev_err(dev, "Invalid %s value %u\n", "maxim,bus-width", priv->bus_width); return -EINVAL; } of_property_read_u32(dev->of_node, "maxim,i2c-remote-bus-hz", &i2c_clk_freq); for (i = 0; i < ARRAY_SIZE(max9286_i2c_speeds); ++i) { const struct max9286_i2c_speed *speed = &max9286_i2c_speeds[i]; if (speed->rate == i2c_clk_freq) { priv->i2c_mstbt = speed->mstbt; break; } } if (i == ARRAY_SIZE(max9286_i2c_speeds)) { dev_err(dev, "Invalid %s value %u\n", "maxim,i2c-remote-bus-hz", i2c_clk_freq); return -EINVAL; } /* * Parse the initial value of the reverse channel amplitude from * the firmware interface and convert it to millivolts. * * Default it to 170mV for backward compatibility with DTBs that do not * provide the property. */ if (of_property_read_u32(dev->of_node, "maxim,reverse-channel-microvolt", &reverse_channel_microvolt)) priv->init_rev_chan_mv = 170; else priv->init_rev_chan_mv = reverse_channel_microvolt / 1000U; priv->route_mask = priv->source_mask; return 0; } static int max9286_get_poc_supplies(struct max9286_priv *priv) { struct device *dev = &priv->client->dev; struct max9286_source *source; int ret; /* Start by getting the global regulator. */ priv->regulator = devm_regulator_get_optional(dev, "poc"); if (!IS_ERR(priv->regulator)) return 0; if (PTR_ERR(priv->regulator) != -ENODEV) return dev_err_probe(dev, PTR_ERR(priv->regulator), "Unable to get PoC regulator\n"); /* If there's no global regulator, get per-port regulators. */ dev_dbg(dev, "No global PoC regulator, looking for per-port regulators\n"); priv->regulator = NULL; for_each_source(priv, source) { unsigned int index = to_index(priv, source); char name[10]; snprintf(name, sizeof(name), "port%u-poc", index); source->regulator = devm_regulator_get(dev, name); if (IS_ERR(source->regulator)) { ret = PTR_ERR(source->regulator); dev_err_probe(dev, ret, "Unable to get port %u PoC regulator\n", index); return ret; } } 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; /* GPIO values default to high */ priv->gpio_state = BIT(0) | BIT(1); ret = max9286_parse_dt(priv); if (ret) goto err_cleanup_dt; priv->gpiod_pwdn = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH); if (IS_ERR(priv->gpiod_pwdn)) { ret = PTR_ERR(priv->gpiod_pwdn); goto err_cleanup_dt; } 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_parse_gpios(priv); if (ret) goto err_powerdown; if (!priv->use_gpio_poc) { ret = max9286_get_poc_supplies(priv); if (ret) goto err_cleanup_dt; } ret = max9286_init(priv); if (ret < 0) goto err_cleanup_dt; return 0; err_powerdown: gpiod_set_value_cansleep(priv->gpiod_pwdn, 0); err_cleanup_dt: max9286_cleanup_dt(priv); return ret; } static void max9286_remove(struct i2c_client *client) { struct max9286_priv *priv = sd_to_max9286(i2c_get_clientdata(client)); i2c_mux_del_adapters(priv->mux); max9286_v4l2_unregister(priv); max9286_poc_enable(priv, false); gpiod_set_value_cansleep(priv->gpiod_pwdn, 0); max9286_cleanup_dt(priv); } 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 = max9286_dt_ids, }, .probe = 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");