This driver implements the Greybus camera protocol.

Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/greybus/camera.c    | 1400 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/greybus/gb-camera.h |  127 +++
 2 files changed, 1527 insertions(+)

--- /dev/null
+++ b/drivers/greybus/camera.c
@@ -0,0 +1,1400 @@
+/*
+ * Greybus Camera protocol driver.
+ *
+ * Copyright 2015 Google Inc.
+ * Copyright 2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+
+#include "gb-camera.h"
+#include "greybus.h"
+#include "greybus_protocols.h"
+
+enum gb_camera_debugs_buffer_id {
+       GB_CAMERA_DEBUGFS_BUFFER_CAPABILITIES,
+       GB_CAMERA_DEBUGFS_BUFFER_STREAMS,
+       GB_CAMERA_DEBUGFS_BUFFER_CAPTURE,
+       GB_CAMERA_DEBUGFS_BUFFER_FLUSH,
+       GB_CAMERA_DEBUGFS_BUFFER_MAX,
+};
+
+struct gb_camera_debugfs_buffer {
+       char data[PAGE_SIZE];
+       size_t length;
+};
+
+enum gb_camera_state {
+       GB_CAMERA_STATE_UNCONFIGURED,
+       GB_CAMERA_STATE_CONFIGURED,
+};
+
+/**
+ * struct gb_camera - A Greybus Camera Device
+ * @connection: the greybus connection for camera management
+ * @data_connection: the greybus connection for camera data
+ * @data_cport_id: the data CPort ID on the module side
+ * @mutex: protects the connection and state fields
+ * @state: the current module state
+ * @debugfs: debugfs entries for camera protocol operations testing
+ * @module: Greybus camera module registered to HOST processor.
+ */
+struct gb_camera {
+       struct gb_bundle *bundle;
+       struct gb_connection *connection;
+       struct gb_connection *data_connection;
+       u16 data_cport_id;
+
+       struct mutex mutex;
+       enum gb_camera_state state;
+
+       struct {
+               struct dentry *root;
+               struct gb_camera_debugfs_buffer *buffers;
+       } debugfs;
+
+       struct gb_camera_module module;
+};
+
+struct gb_camera_stream_config {
+       unsigned int width;
+       unsigned int height;
+       unsigned int format;
+       unsigned int vc;
+       unsigned int dt[2];
+       unsigned int max_size;
+};
+
+struct gb_camera_fmt_info {
+       enum v4l2_mbus_pixelcode mbus_code;
+       unsigned int gb_format;
+       unsigned int bpp;
+};
+
+/* GB format to media code map */
+static const struct gb_camera_fmt_info gb_fmt_info[] = {
+       {
+               .mbus_code = V4L2_MBUS_FMT_UYVY8_1X16,
+               .gb_format = 0x01,
+               .bpp       = 16,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_NV12_1x8,
+               .gb_format = 0x12,
+               .bpp       = 12,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_NV21_1x8,
+               .gb_format = 0x13,
+               .bpp       = 12,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_YU12_1x8,
+               .gb_format = 0x16,
+               .bpp       = 12,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_YV12_1x8,
+               .gb_format = 0x17,
+               .bpp       = 12,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_JPEG_1X8,
+               .gb_format = 0x40,
+               .bpp       = 0,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_GB_CAM_METADATA_1X8,
+               .gb_format = 0x41,
+               .bpp       = 0,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_GB_CAM_DEBUG_DATA_1X8,
+               .gb_format = 0x42,
+               .bpp       = 0,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_SBGGR10_1X10,
+               .gb_format = 0x80,
+               .bpp       = 10,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_SGBRG10_1X10,
+               .gb_format = 0x81,
+               .bpp       = 10,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_SGRBG10_1X10,
+               .gb_format = 0x82,
+               .bpp       = 10,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_SRGGB10_1X10,
+               .gb_format = 0x83,
+               .bpp       = 10,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_SBGGR12_1X12,
+               .gb_format = 0x84,
+               .bpp       = 12,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_SGBRG12_1X12,
+               .gb_format = 0x85,
+               .bpp       = 12,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_SGRBG12_1X12,
+               .gb_format = 0x86,
+               .bpp       = 12,
+       },
+       {
+               .mbus_code = V4L2_MBUS_FMT_SRGGB12_1X12,
+               .gb_format = 0x87,
+               .bpp       = 12,
+       },
+};
+
+static const struct gb_camera_fmt_info *gb_camera_get_format_info(u16 gb_fmt)
+{
+       unsigned int i;
+
+       for (i = 0; i < ARRAY_SIZE(gb_fmt_info); i++) {
+               if (gb_fmt_info[i].gb_format == gb_fmt)
+                       return &gb_fmt_info[i];
+       }
+
+       return NULL;
+}
+
+#define ES2_APB_CDSI0_CPORT            16
+#define ES2_APB_CDSI1_CPORT            17
+
+#define GB_CAMERA_MAX_SETTINGS_SIZE    8192
+
+#define gcam_dbg(gcam, format...)      dev_dbg(&gcam->bundle->dev, format)
+#define gcam_info(gcam, format...)     dev_info(&gcam->bundle->dev, format)
+#define gcam_err(gcam, format...)      dev_err(&gcam->bundle->dev, format)
+
+static int gb_camera_operation_sync_flags(struct gb_connection *connection,
+                                         int type, unsigned int flags,
+                                         void *request, size_t request_size,
+                                         void *response, size_t *response_size)
+{
+       struct gb_operation *operation;
+       int ret;
+
+       operation = gb_operation_create_flags(connection, type, request_size,
+                                             *response_size, flags,
+                                             GFP_KERNEL);
+       if (!operation)
+               return  -ENOMEM;
+
+       if (request_size)
+               memcpy(operation->request->payload, request, request_size);
+
+       ret = gb_operation_request_send_sync(operation);
+       if (ret) {
+               dev_err(&connection->hd->dev,
+                       "%s: synchronous operation of type 0x%02x failed: %d\n",
+                       connection->name, type, ret);
+       } else {
+               *response_size = operation->response->payload_size;
+
+               if (operation->response->payload_size)
+                       memcpy(response, operation->response->payload,
+                              operation->response->payload_size);
+       }
+
+       gb_operation_put(operation);
+
+       return ret;
+}
+
+static int gb_camera_get_max_pkt_size(struct gb_camera *gcam,
+               struct gb_camera_configure_streams_response *resp)
+{
+       unsigned int max_pkt_size = 0;
+       unsigned int i;
+
+       for (i = 0; i < resp->num_streams; i++) {
+               struct gb_camera_stream_config_response *cfg = &resp->config[i];
+               const struct gb_camera_fmt_info *fmt_info;
+               unsigned int pkt_size;
+
+               fmt_info = gb_camera_get_format_info(cfg->format);
+               if (!fmt_info) {
+                       gcam_err(gcam, "unsupported greybus image format: %d\n",
+                                cfg->format);
+                       return -EIO;
+               }
+
+               if (fmt_info->bpp == 0) {
+                       pkt_size = le32_to_cpu(cfg->max_pkt_size);
+
+                       if (pkt_size == 0) {
+                               gcam_err(gcam,
+                                        "Stream %u: invalid zero maximum 
packet size\n",
+                                        i);
+                               return -EIO;
+                       }
+               } else {
+                       pkt_size = le16_to_cpu(cfg->width) * fmt_info->bpp / 8;
+
+                       if (pkt_size != le32_to_cpu(cfg->max_pkt_size)) {
+                               gcam_err(gcam,
+                                        "Stream %u: maximum packet size 
mismatch (%u/%u)\n",
+                                        i, pkt_size, cfg->max_pkt_size);
+                               return -EIO;
+                       }
+               }
+
+               max_pkt_size = max(pkt_size, max_pkt_size);
+       }
+
+       return max_pkt_size;
+}
+
+/*
+ * Validate the stream configuration response verifying padding is correctly
+ * set and the returned number of streams is supported
+ */
+static const int gb_camera_configure_streams_validate_response(
+               struct gb_camera *gcam,
+               struct gb_camera_configure_streams_response *resp,
+               unsigned int nstreams)
+{
+       unsigned int i;
+
+       /* Validate the returned response structure */
+       if (resp->padding[0] || resp->padding[1]) {
+               gcam_err(gcam, "response padding != 0\n");
+               return -EIO;
+       }
+
+       if (resp->num_streams > nstreams) {
+               gcam_err(gcam, "got #streams %u > request %u\n",
+                        resp->num_streams, nstreams);
+               return -EIO;
+       }
+
+       for (i = 0; i < resp->num_streams; i++) {
+               struct gb_camera_stream_config_response *cfg = &resp->config[i];
+               if (cfg->padding) {
+                       gcam_err(gcam, "stream #%u padding != 0\n", i);
+                       return -EIO;
+               }
+       }
+
+       return 0;
+}
+
+/* 
-----------------------------------------------------------------------------
+ * Hardware Configuration
+ */
+
+static int gb_camera_set_intf_power_mode(struct gb_camera *gcam, u8 intf_id,
+                                        bool hs)
+{
+       struct gb_svc *svc = gcam->connection->hd->svc;
+       int ret;
+
+       if (hs)
+               ret = gb_svc_intf_set_power_mode(svc, intf_id,
+                                                GB_SVC_UNIPRO_HS_SERIES_A,
+                                                GB_SVC_UNIPRO_FAST_MODE, 2, 2,
+                                                GB_SVC_SMALL_AMPLITUDE,
+                                                GB_SVC_NO_DE_EMPHASIS,
+                                                GB_SVC_UNIPRO_FAST_MODE, 2, 2,
+                                                GB_SVC_PWRM_RXTERMINATION |
+                                                GB_SVC_PWRM_TXTERMINATION, 0,
+                                                NULL, NULL);
+       else
+               ret = gb_svc_intf_set_power_mode(svc, intf_id,
+                                                GB_SVC_UNIPRO_HS_SERIES_A,
+                                                GB_SVC_UNIPRO_SLOW_AUTO_MODE,
+                                                2, 1,
+                                                GB_SVC_SMALL_AMPLITUDE,
+                                                GB_SVC_NO_DE_EMPHASIS,
+                                                GB_SVC_UNIPRO_SLOW_AUTO_MODE,
+                                                2, 1,
+                                                0, 0,
+                                                NULL, NULL);
+
+       return ret;
+}
+
+static int gb_camera_set_power_mode(struct gb_camera *gcam, bool hs)
+{
+       struct gb_interface *intf = gcam->connection->intf;
+       struct gb_svc *svc = gcam->connection->hd->svc;
+       int ret;
+
+       ret = gb_camera_set_intf_power_mode(gcam, intf->interface_id, hs);
+       if (ret < 0) {
+               gcam_err(gcam, "failed to set module interface to %s (%d)\n",
+                        hs ? "HS" : "PWM", ret);
+               return ret;
+       }
+
+       ret = gb_camera_set_intf_power_mode(gcam, svc->ap_intf_id, hs);
+       if (ret < 0) {
+               gb_camera_set_intf_power_mode(gcam, intf->interface_id, !hs);
+               gcam_err(gcam, "failed to set AP interface to %s (%d)\n",
+                        hs ? "HS" : "PWM", ret);
+               return ret;
+       }
+
+       return 0;
+}
+
+struct ap_csi_config_request {
+       __u8 csi_id;
+       __u8 flags;
+#define GB_CAMERA_CSI_FLAG_CLOCK_CONTINUOUS 0x01
+       __u8 num_lanes;
+       __u8 padding;
+       __le32 csi_clk_freq;
+       __le32 max_pkt_size;
+} __packed;
+
+/*
+ * TODO: Compute the number of lanes dynamically based on bandwidth
+ * requirements.
+ */
+#define GB_CAMERA_CSI_NUM_DATA_LANES           4
+
+#define GB_CAMERA_CSI_CLK_FREQ_MAX             999000000U
+#define GB_CAMERA_CSI_CLK_FREQ_MIN             100000000U
+#define GB_CAMERA_CSI_CLK_FREQ_MARGIN          150000000U
+
+static int gb_camera_setup_data_connection(struct gb_camera *gcam,
+               struct gb_camera_configure_streams_response *resp,
+               struct gb_camera_csi_params *csi_params)
+{
+       struct ap_csi_config_request csi_cfg;
+       struct gb_connection *conn;
+       unsigned int clk_freq;
+       int ret;
+
+       /*
+        * Create the data connection between the camera module data CPort and
+        * APB CDSI1. The CDSI1 CPort ID is hardcoded by the ES2 bridge.
+        */
+       conn = gb_connection_create_offloaded(gcam->bundle, gcam->data_cport_id,
+                                             GB_CONNECTION_FLAG_NO_FLOWCTRL |
+                                             GB_CONNECTION_FLAG_CDSI1);
+       if (IS_ERR(conn))
+               return PTR_ERR(conn);
+
+       gcam->data_connection = conn;
+       gb_connection_set_data(conn, gcam);
+
+       ret = gb_connection_enable(conn);
+       if (ret)
+               goto error_conn_destroy;
+
+       /* Set the UniPro link to high speed mode. */
+       ret = gb_camera_set_power_mode(gcam, true);
+       if (ret < 0)
+               goto error_conn_disable;
+
+       /*
+        * Configure the APB-A CSI-2 transmitter.
+        *
+        * Hardcode the number of lanes to 4 and compute the bus clock frequency
+        * based on the module bandwidth requirements with a safety margin.
+        */
+       memset(&csi_cfg, 0, sizeof(csi_cfg));
+       csi_cfg.csi_id = 1;
+       csi_cfg.flags = 0;
+       csi_cfg.num_lanes = GB_CAMERA_CSI_NUM_DATA_LANES;
+
+       clk_freq = resp->data_rate / 2 / GB_CAMERA_CSI_NUM_DATA_LANES;
+       clk_freq = clamp(clk_freq + GB_CAMERA_CSI_CLK_FREQ_MARGIN,
+                        GB_CAMERA_CSI_CLK_FREQ_MIN,
+                        GB_CAMERA_CSI_CLK_FREQ_MAX);
+       csi_cfg.csi_clk_freq = clk_freq;
+
+       ret = gb_camera_get_max_pkt_size(gcam, resp);
+       if (ret < 0) {
+               ret = -EIO;
+               goto error_power;
+       }
+       csi_cfg.max_pkt_size = ret;
+
+       ret = gb_hd_output(gcam->connection->hd, &csi_cfg,
+                          sizeof(csi_cfg),
+                          GB_APB_REQUEST_CSI_TX_CONTROL, false);
+       if (ret < 0) {
+               gcam_err(gcam, "failed to start the CSI transmitter\n");
+               goto error_power;
+       }
+
+       if (csi_params) {
+               csi_params->clk_freq = csi_cfg.csi_clk_freq;
+               csi_params->num_lanes = csi_cfg.num_lanes;
+       }
+
+       return 0;
+
+error_power:
+       gb_camera_set_power_mode(gcam, false);
+error_conn_disable:
+       gb_connection_disable(gcam->data_connection);
+error_conn_destroy:
+       gb_connection_destroy(gcam->data_connection);
+       gcam->data_connection = NULL;
+       return ret;
+}
+
+static void gb_camera_teardown_data_connection(struct gb_camera *gcam)
+{
+       struct ap_csi_config_request csi_cfg;
+       int ret;
+
+       /* Stop the APB1 CSI transmitter. */
+       memset(&csi_cfg, 0, sizeof(csi_cfg));
+       csi_cfg.csi_id = 1;
+
+       ret = gb_hd_output(gcam->connection->hd, &csi_cfg,
+                          sizeof(csi_cfg),
+                          GB_APB_REQUEST_CSI_TX_CONTROL, false);
+
+       if (ret < 0)
+               gcam_err(gcam, "failed to stop the CSI transmitter\n");
+
+       /* Set the UniPro link to low speed mode. */
+       gb_camera_set_power_mode(gcam, false);
+
+       /* Destroy the data connection. */
+       gb_connection_disable(gcam->data_connection);
+       gb_connection_destroy(gcam->data_connection);
+       gcam->data_connection = NULL;
+}
+
+/* 
-----------------------------------------------------------------------------
+ * Camera Protocol Operations
+ */
+
+static int gb_camera_capabilities(struct gb_camera *gcam,
+                                 u8 *capabilities, size_t *size)
+{
+       int ret;
+
+       ret = gb_pm_runtime_get_sync(gcam->bundle);
+       if (ret)
+               return ret;
+
+       mutex_lock(&gcam->mutex);
+
+       if (!gcam->connection) {
+               ret = -EINVAL;
+               goto done;
+       }
+
+       ret = gb_camera_operation_sync_flags(gcam->connection,
+                                            GB_CAMERA_TYPE_CAPABILITIES,
+                                            GB_OPERATION_FLAG_SHORT_RESPONSE,
+                                            NULL, 0,
+                                            (void *)capabilities, size);
+       if (ret)
+               gcam_err(gcam, "failed to retrieve capabilities: %d\n", ret);
+
+done:
+       mutex_unlock(&gcam->mutex);
+
+       gb_pm_runtime_put_autosuspend(gcam->bundle);
+
+       return ret;
+}
+
+static int gb_camera_configure_streams(struct gb_camera *gcam,
+                                      unsigned int *num_streams,
+                                      unsigned int *flags,
+                                      struct gb_camera_stream_config *streams,
+                                      struct gb_camera_csi_params *csi_params)
+{
+       struct gb_camera_configure_streams_request *req;
+       struct gb_camera_configure_streams_response *resp;
+       unsigned int nstreams = *num_streams;
+       unsigned int i;
+       size_t req_size;
+       size_t resp_size;
+       int ret;
+
+       if (nstreams > GB_CAMERA_MAX_STREAMS)
+               return -EINVAL;
+
+       req_size = sizeof(*req) + nstreams * sizeof(req->config[0]);
+       resp_size = sizeof(*resp) + nstreams * sizeof(resp->config[0]);
+
+       req = kmalloc(req_size, GFP_KERNEL);
+       resp = kmalloc(resp_size, GFP_KERNEL);
+       if (!req || !resp) {
+               kfree(req);
+               kfree(resp);
+               return -ENOMEM;
+       }
+
+       req->num_streams = nstreams;
+       req->flags = *flags;
+       req->padding = 0;
+
+       for (i = 0; i < nstreams; ++i) {
+               struct gb_camera_stream_config_request *cfg = &req->config[i];
+
+               cfg->width = cpu_to_le16(streams[i].width);
+               cfg->height = cpu_to_le16(streams[i].height);
+               cfg->format = cpu_to_le16(streams[i].format);
+               cfg->padding = 0;
+       }
+
+       mutex_lock(&gcam->mutex);
+
+       ret = gb_pm_runtime_get_sync(gcam->bundle);
+       if (ret)
+               goto done_skip_pm_put;
+
+       if (!gcam->connection) {
+               ret = -EINVAL;
+               goto done;
+       }
+
+       ret = gb_camera_operation_sync_flags(gcam->connection,
+                                            GB_CAMERA_TYPE_CONFIGURE_STREAMS,
+                                            GB_OPERATION_FLAG_SHORT_RESPONSE,
+                                            req, req_size,
+                                            resp, &resp_size);
+       if (ret < 0)
+               goto done;
+
+       ret = gb_camera_configure_streams_validate_response(gcam, resp,
+                                                           nstreams);
+       if (ret < 0)
+               goto done;
+
+       *flags = resp->flags;
+       *num_streams = resp->num_streams;
+
+       for (i = 0; i < resp->num_streams; ++i) {
+               struct gb_camera_stream_config_response *cfg = &resp->config[i];
+
+               streams[i].width = le16_to_cpu(cfg->width);
+               streams[i].height = le16_to_cpu(cfg->height);
+               streams[i].format = le16_to_cpu(cfg->format);
+               streams[i].vc = cfg->virtual_channel;
+               streams[i].dt[0] = cfg->data_type[0];
+               streams[i].dt[1] = cfg->data_type[1];
+               streams[i].max_size = le32_to_cpu(cfg->max_size);
+       }
+
+       if ((resp->flags & GB_CAMERA_CONFIGURE_STREAMS_ADJUSTED) ||
+           (req->flags & GB_CAMERA_CONFIGURE_STREAMS_TEST_ONLY))
+               goto done;
+
+       if (gcam->state == GB_CAMERA_STATE_CONFIGURED) {
+               gb_camera_teardown_data_connection(gcam);
+               gcam->state = GB_CAMERA_STATE_UNCONFIGURED;
+
+               /*
+                * When unconfiguring streams release the PM runtime reference
+                * that was acquired when streams were configured. The bundle
+                * won't be suspended until the PM runtime reference acquired at
+                * the beginning of this function gets released right before
+                * returning.
+                */
+               gb_pm_runtime_put_noidle(gcam->bundle);
+       }
+
+       if (resp->num_streams == 0)
+               goto done;
+
+       /*
+        * Make sure the bundle won't be suspended until streams get
+        * unconfigured after the stream is configured successfully
+        */
+       gb_pm_runtime_get_noresume(gcam->bundle);
+
+       /* Setup CSI-2 connection from APB-A to AP */
+       ret = gb_camera_setup_data_connection(gcam, resp, csi_params);
+       if (ret < 0) {
+               memset(req, 0, sizeof(*req));
+               gb_operation_sync(gcam->connection,
+                                 GB_CAMERA_TYPE_CONFIGURE_STREAMS,
+                                 req, sizeof(*req),
+                                 resp, sizeof(*resp));
+               *flags = 0;
+               *num_streams = 0;
+               gb_pm_runtime_put_noidle(gcam->bundle);
+               goto done;
+       }
+
+       gcam->state = GB_CAMERA_STATE_CONFIGURED;
+
+done:
+       gb_pm_runtime_put_autosuspend(gcam->bundle);
+
+done_skip_pm_put:
+       mutex_unlock(&gcam->mutex);
+       kfree(req);
+       kfree(resp);
+       return ret;
+}
+
+static int gb_camera_capture(struct gb_camera *gcam, u32 request_id,
+                            unsigned int streams, unsigned int num_frames,
+                            size_t settings_size, const void *settings)
+{
+       struct gb_camera_capture_request *req;
+       size_t req_size;
+       int ret;
+
+       if (settings_size > GB_CAMERA_MAX_SETTINGS_SIZE)
+               return -EINVAL;
+
+       req_size = sizeof(*req) + settings_size;
+       req = kmalloc(req_size, GFP_KERNEL);
+       if (!req)
+               return -ENOMEM;
+
+       req->request_id = cpu_to_le32(request_id);
+       req->streams = streams;
+       req->padding = 0;
+       req->num_frames = cpu_to_le16(num_frames);
+       memcpy(req->settings, settings, settings_size);
+
+       mutex_lock(&gcam->mutex);
+
+       if (!gcam->connection) {
+               ret = -EINVAL;
+               goto done;
+       }
+
+       ret = gb_operation_sync(gcam->connection, GB_CAMERA_TYPE_CAPTURE,
+                               req, req_size, NULL, 0);
+done:
+       mutex_unlock(&gcam->mutex);
+
+       kfree(req);
+
+       return ret;
+}
+
+static int gb_camera_flush(struct gb_camera *gcam, u32 *request_id)
+{
+       struct gb_camera_flush_response resp;
+       int ret;
+
+       mutex_lock(&gcam->mutex);
+
+       if (!gcam->connection) {
+               ret = -EINVAL;
+               goto done;
+       }
+
+       ret = gb_operation_sync(gcam->connection, GB_CAMERA_TYPE_FLUSH, NULL, 0,
+                               &resp, sizeof(resp));
+
+       if (ret < 0)
+               goto done;
+
+       if (request_id)
+               *request_id = le32_to_cpu(resp.request_id);
+
+done:
+       mutex_unlock(&gcam->mutex);
+
+       return ret;
+}
+
+static int gb_camera_request_handler(struct gb_operation *op)
+{
+       struct gb_camera *gcam = gb_connection_get_data(op->connection);
+       struct gb_camera_metadata_request *payload;
+       struct gb_message *request;
+
+       if (op->type != GB_CAMERA_TYPE_METADATA) {
+               gcam_err(gcam, "Unsupported unsolicited event: %u\n", op->type);
+               return -EINVAL;
+       }
+
+       request = op->request;
+
+       if (request->payload_size < sizeof(*payload)) {
+               gcam_err(gcam, "Wrong event size received (%zu < %zu)\n",
+                        request->payload_size, sizeof(*payload));
+               return -EINVAL;
+       }
+
+       payload = request->payload;
+
+       gcam_dbg(gcam, "received metadata for request %u, frame %u, stream 
%u\n",
+                payload->request_id, payload->frame_number, payload->stream);
+
+       return 0;
+}
+
+/* 
-----------------------------------------------------------------------------
+ * Interface with HOST gmp camera.
+ */
+static unsigned int gb_camera_mbus_to_gb(enum v4l2_mbus_pixelcode mbus_code)
+{
+       unsigned int i;
+
+       for (i = 0; i < ARRAY_SIZE(gb_fmt_info); i++) {
+               if (gb_fmt_info[i].mbus_code == mbus_code)
+                       return gb_fmt_info[i].gb_format;
+       }
+       return gb_fmt_info[0].gb_format;
+}
+
+static enum v4l2_mbus_pixelcode gb_camera_gb_to_mbus(u16 gb_fmt)
+{
+       unsigned int i;
+
+       for (i = 0; i < ARRAY_SIZE(gb_fmt_info); i++) {
+               if (gb_fmt_info[i].gb_format == gb_fmt)
+                       return gb_fmt_info[i].mbus_code;
+       }
+       return gb_fmt_info[0].mbus_code;
+}
+
+static ssize_t gb_camera_op_capabilities(void *priv, char *data, size_t len)
+{
+       struct gb_camera *gcam = priv;
+       size_t capabilities_len = len;
+       int ret;
+
+       ret = gb_camera_capabilities(gcam, data, &capabilities_len);
+       if (ret)
+               return ret;
+
+       return capabilities_len;
+}
+
+static int gb_camera_op_configure_streams(void *priv, unsigned int *nstreams,
+               unsigned int *flags, struct gb_camera_stream *streams,
+               struct gb_camera_csi_params *csi_params)
+{
+       struct gb_camera *gcam = priv;
+       struct gb_camera_stream_config *gb_streams;
+       unsigned int gb_flags = 0;
+       unsigned int gb_nstreams = *nstreams;
+       unsigned int i;
+       int ret;
+
+       if (gb_nstreams > GB_CAMERA_MAX_STREAMS)
+               return -EINVAL;
+
+       gb_streams = kzalloc(gb_nstreams * sizeof(*gb_streams), GFP_KERNEL);
+       if (!gb_streams)
+               return -ENOMEM;
+
+       for (i = 0; i < gb_nstreams; i++) {
+               gb_streams[i].width = streams[i].width;
+               gb_streams[i].height = streams[i].height;
+               gb_streams[i].format =
+                       gb_camera_mbus_to_gb(streams[i].pixel_code);
+       }
+
+       if (*flags & GB_CAMERA_IN_FLAG_TEST)
+               gb_flags |= GB_CAMERA_CONFIGURE_STREAMS_TEST_ONLY;
+
+       ret = gb_camera_configure_streams(gcam, &gb_nstreams,
+                                         &gb_flags, gb_streams, csi_params);
+       if (ret < 0)
+               goto done;
+       if (gb_nstreams > *nstreams) {
+               ret = -EINVAL;
+               goto done;
+       }
+
+       *flags = 0;
+       if (gb_flags & GB_CAMERA_CONFIGURE_STREAMS_ADJUSTED)
+               *flags |= GB_CAMERA_OUT_FLAG_ADJUSTED;
+
+       for (i = 0; i < gb_nstreams; i++) {
+               streams[i].width = gb_streams[i].width;
+               streams[i].height = gb_streams[i].height;
+               streams[i].vc = gb_streams[i].vc;
+               streams[i].dt[0] = gb_streams[i].dt[0];
+               streams[i].dt[1] = gb_streams[i].dt[1];
+               streams[i].max_size = gb_streams[i].max_size;
+               streams[i].pixel_code =
+                       gb_camera_gb_to_mbus(gb_streams[i].format);
+       }
+       *nstreams = gb_nstreams;
+
+done:
+       kfree(gb_streams);
+       return ret;
+}
+
+static int gb_camera_op_capture(void *priv, u32 request_id,
+               unsigned int streams, unsigned int num_frames,
+               size_t settings_size, const void *settings)
+{
+       struct gb_camera *gcam = priv;
+
+       return gb_camera_capture(gcam, request_id, streams, num_frames,
+                                settings_size, settings);
+}
+
+static int gb_camera_op_flush(void *priv, u32 *request_id)
+{
+       struct gb_camera *gcam = priv;
+
+       return gb_camera_flush(gcam, request_id);
+}
+
+static const struct gb_camera_ops gb_cam_ops = {
+       .capabilities = gb_camera_op_capabilities,
+       .configure_streams = gb_camera_op_configure_streams,
+       .capture = gb_camera_op_capture,
+       .flush = gb_camera_op_flush,
+};
+
+/* 
-----------------------------------------------------------------------------
+ * DebugFS
+ */
+
+static ssize_t gb_camera_debugfs_capabilities(struct gb_camera *gcam,
+               char *buf, size_t len)
+{
+       struct gb_camera_debugfs_buffer *buffer =
+               &gcam->debugfs.buffers[GB_CAMERA_DEBUGFS_BUFFER_CAPABILITIES];
+       size_t size = 1024;
+       unsigned int i;
+       u8 *caps;
+       int ret;
+
+       caps = kmalloc(size, GFP_KERNEL);
+       if (!caps)
+               return -ENOMEM;
+
+       ret = gb_camera_capabilities(gcam, caps, &size);
+       if (ret < 0)
+               goto done;
+
+       /*
+        * hex_dump_to_buffer() doesn't return the number of bytes dumped prior
+        * to v4.0, we need our own implementation :-(
+        */
+       buffer->length = 0;
+
+       for (i = 0; i < size; i += 16) {
+               unsigned int nbytes = min_t(unsigned int, size - i, 16);
+
+               buffer->length += sprintf(buffer->data + buffer->length,
+                                         "%*ph\n", nbytes, caps + i);
+       }
+
+done:
+       kfree(caps);
+       return ret;
+}
+
+static ssize_t gb_camera_debugfs_configure_streams(struct gb_camera *gcam,
+               char *buf, size_t len)
+{
+       struct gb_camera_debugfs_buffer *buffer =
+               &gcam->debugfs.buffers[GB_CAMERA_DEBUGFS_BUFFER_STREAMS];
+       struct gb_camera_stream_config *streams;
+       unsigned int nstreams;
+       unsigned int flags;
+       unsigned int i;
+       char *token;
+       int ret;
+
+       /* Retrieve number of streams to configure */
+       token = strsep(&buf, ";");
+       if (token == NULL)
+               return -EINVAL;
+
+       ret = kstrtouint(token, 10, &nstreams);
+       if (ret < 0)
+               return ret;
+
+       if (nstreams > GB_CAMERA_MAX_STREAMS)
+               return -EINVAL;
+
+       token = strsep(&buf, ";");
+       if (token == NULL)
+               return -EINVAL;
+
+       ret = kstrtouint(token, 10, &flags);
+       if (ret < 0)
+               return ret;
+
+       /* For each stream to configure parse width, height and format */
+       streams = kzalloc(nstreams * sizeof(*streams), GFP_KERNEL);
+       if (!streams)
+               return -ENOMEM;
+
+       for (i = 0; i < nstreams; ++i) {
+               struct gb_camera_stream_config *stream = &streams[i];
+
+               /* width */
+               token = strsep(&buf, ";");
+               if (token == NULL) {
+                       ret = -EINVAL;
+                       goto done;
+               }
+               ret = kstrtouint(token, 10, &stream->width);
+               if (ret < 0)
+                       goto done;
+
+               /* height */
+               token = strsep(&buf, ";");
+               if (token == NULL)
+                       goto done;
+
+               ret = kstrtouint(token, 10, &stream->height);
+               if (ret < 0)
+                       goto done;
+
+               /* Image format code */
+               token = strsep(&buf, ";");
+               if (token == NULL)
+                       goto done;
+
+               ret = kstrtouint(token, 16, &stream->format);
+               if (ret < 0)
+                       goto done;
+       }
+
+       ret = gb_camera_configure_streams(gcam, &nstreams, &flags, streams,
+                                         NULL);
+       if (ret < 0)
+               goto done;
+
+       buffer->length = sprintf(buffer->data, "%u;%u;", nstreams, flags);
+
+       for (i = 0; i < nstreams; ++i) {
+               struct gb_camera_stream_config *stream = &streams[i];
+
+               buffer->length += sprintf(buffer->data + buffer->length,
+                                         "%u;%u;%u;%u;%u;%u;%u;",
+                                         stream->width, stream->height,
+                                         stream->format, stream->vc,
+                                         stream->dt[0], stream->dt[1],
+                                         stream->max_size);
+       }
+
+       ret = len;
+
+done:
+       kfree(streams);
+       return ret;
+};
+
+static ssize_t gb_camera_debugfs_capture(struct gb_camera *gcam,
+               char *buf, size_t len)
+{
+       unsigned int request_id;
+       unsigned int streams_mask;
+       unsigned int num_frames;
+       char *token;
+       int ret;
+
+       /* Request id */
+       token = strsep(&buf, ";");
+       if (token == NULL)
+               return -EINVAL;
+       ret = kstrtouint(token, 10, &request_id);
+       if (ret < 0)
+               return ret;
+
+       /* Stream mask */
+       token = strsep(&buf, ";");
+       if (token == NULL)
+               return -EINVAL;
+       ret = kstrtouint(token, 16, &streams_mask);
+       if (ret < 0)
+               return ret;
+
+       /* number of frames */
+       token = strsep(&buf, ";");
+       if (token == NULL)
+               return -EINVAL;
+       ret = kstrtouint(token, 10, &num_frames);
+       if (ret < 0)
+               return ret;
+
+       ret = gb_camera_capture(gcam, request_id, streams_mask, num_frames, 0,
+                               NULL);
+       if (ret < 0)
+               return ret;
+
+       return len;
+}
+
+static ssize_t gb_camera_debugfs_flush(struct gb_camera *gcam,
+               char *buf, size_t len)
+{
+       struct gb_camera_debugfs_buffer *buffer =
+               &gcam->debugfs.buffers[GB_CAMERA_DEBUGFS_BUFFER_FLUSH];
+       unsigned int req_id;
+       int ret;
+
+       ret = gb_camera_flush(gcam, &req_id);
+       if (ret < 0)
+               return ret;
+
+       buffer->length = sprintf(buffer->data, "%u", req_id);
+
+       return len;
+}
+
+struct gb_camera_debugfs_entry {
+       const char *name;
+       unsigned int mask;
+       unsigned int buffer;
+       ssize_t (*execute)(struct gb_camera *gcam, char *buf, size_t len);
+};
+
+static const struct gb_camera_debugfs_entry gb_camera_debugfs_entries[] = {
+       {
+               .name = "capabilities",
+               .mask = S_IFREG | S_IRUGO,
+               .buffer = GB_CAMERA_DEBUGFS_BUFFER_CAPABILITIES,
+               .execute = gb_camera_debugfs_capabilities,
+       }, {
+               .name = "configure_streams",
+               .mask = S_IFREG | S_IRUGO | S_IWUGO,
+               .buffer = GB_CAMERA_DEBUGFS_BUFFER_STREAMS,
+               .execute = gb_camera_debugfs_configure_streams,
+       }, {
+               .name = "capture",
+               .mask = S_IFREG | S_IRUGO | S_IWUGO,
+               .buffer = GB_CAMERA_DEBUGFS_BUFFER_CAPTURE,
+               .execute = gb_camera_debugfs_capture,
+       }, {
+               .name = "flush",
+               .mask = S_IFREG | S_IRUGO | S_IWUGO,
+               .buffer = GB_CAMERA_DEBUGFS_BUFFER_FLUSH,
+               .execute = gb_camera_debugfs_flush,
+       },
+};
+
+static ssize_t gb_camera_debugfs_read(struct file *file, char __user *buf,
+                                     size_t len, loff_t *offset)
+{
+       const struct gb_camera_debugfs_entry *op = file->private_data;
+       struct gb_camera *gcam = file->f_inode->i_private;
+       struct gb_camera_debugfs_buffer *buffer;
+       ssize_t ret;
+
+       /* For read-only entries the operation is triggered by a read. */
+       if (!(op->mask & S_IWUGO)) {
+               ret = op->execute(gcam, NULL, 0);
+               if (ret < 0)
+                       return ret;
+       }
+
+       buffer = &gcam->debugfs.buffers[op->buffer];
+
+       return simple_read_from_buffer(buf, len, offset, buffer->data,
+                                      buffer->length);
+}
+
+static ssize_t gb_camera_debugfs_write(struct file *file,
+                                      const char __user *buf, size_t len,
+                                      loff_t *offset)
+{
+       const struct gb_camera_debugfs_entry *op = file->private_data;
+       struct gb_camera *gcam = file->f_inode->i_private;
+       ssize_t ret;
+       char *kbuf;
+
+       if (len > 1024)
+              return -EINVAL;
+
+       kbuf = kmalloc(len + 1, GFP_KERNEL);
+       if (kbuf == NULL)
+               return -ENOMEM;
+
+       if (copy_from_user(kbuf, buf, len)) {
+               ret = -EFAULT;
+               goto done;
+       }
+
+       kbuf[len] = '\0';
+
+       ret = op->execute(gcam, kbuf, len);
+
+done:
+       kfree(kbuf);
+       return ret;
+}
+
+static int gb_camera_debugfs_open(struct inode *inode, struct file *file)
+{
+       unsigned int i;
+
+       for (i = 0; i < ARRAY_SIZE(gb_camera_debugfs_entries); ++i) {
+               const struct gb_camera_debugfs_entry *entry =
+                       &gb_camera_debugfs_entries[i];
+
+               if (!strcmp(file->f_path.dentry->d_iname, entry->name)) {
+                       file->private_data = (void *)entry;
+                       break;
+               }
+       }
+
+       return 0;
+}
+
+static const struct file_operations gb_camera_debugfs_ops = {
+       .open = gb_camera_debugfs_open,
+       .read = gb_camera_debugfs_read,
+       .write = gb_camera_debugfs_write,
+};
+
+static int gb_camera_debugfs_init(struct gb_camera *gcam)
+{
+       struct gb_connection *connection = gcam->connection;
+       char dirname[27];
+       unsigned int i;
+
+       /*
+        * Create root debugfs entry and a file entry for each camera operation.
+        */
+       snprintf(dirname, 27, "camera-%u.%u", connection->intf->interface_id,
+                gcam->bundle->id);
+
+       gcam->debugfs.root = debugfs_create_dir(dirname, gb_debugfs_get());
+       if (IS_ERR(gcam->debugfs.root)) {
+               gcam_err(gcam, "debugfs root create failed (%ld)\n",
+                        PTR_ERR(gcam->debugfs.root));
+               return PTR_ERR(gcam->debugfs.root);
+       }
+
+       gcam->debugfs.buffers = vmalloc(sizeof(*gcam->debugfs.buffers) *
+                                       GB_CAMERA_DEBUGFS_BUFFER_MAX);
+       if (!gcam->debugfs.buffers)
+               return -ENOMEM;
+
+       for (i = 0; i < ARRAY_SIZE(gb_camera_debugfs_entries); ++i) {
+               const struct gb_camera_debugfs_entry *entry =
+                       &gb_camera_debugfs_entries[i];
+               struct dentry *dentry;
+
+               gcam->debugfs.buffers[i].length = 0;
+
+               dentry = debugfs_create_file(entry->name, entry->mask,
+                                            gcam->debugfs.root, gcam,
+                                            &gb_camera_debugfs_ops);
+               if (IS_ERR(dentry)) {
+                       gcam_err(gcam,
+                                "debugfs operation %s create failed (%ld)\n",
+                                entry->name, PTR_ERR(dentry));
+                       return PTR_ERR(dentry);
+               }
+       }
+
+       return 0;
+}
+
+static void gb_camera_debugfs_cleanup(struct gb_camera *gcam)
+{
+       debugfs_remove_recursive(gcam->debugfs.root);
+
+       vfree(gcam->debugfs.buffers);
+}
+
+/* 
-----------------------------------------------------------------------------
+ * Init & Cleanup
+ */
+
+static void gb_camera_cleanup(struct gb_camera *gcam)
+{
+       gb_camera_debugfs_cleanup(gcam);
+
+       mutex_lock(&gcam->mutex);
+       if (gcam->data_connection) {
+               gb_connection_disable(gcam->data_connection);
+               gb_connection_destroy(gcam->data_connection);
+               gcam->data_connection = NULL;
+       }
+
+       if (gcam->connection) {
+               gb_connection_disable(gcam->connection);
+               gb_connection_destroy(gcam->connection);
+               gcam->connection = NULL;
+       }
+       mutex_unlock(&gcam->mutex);
+}
+
+static void gb_camera_release_module(struct kref *ref)
+{
+       struct gb_camera_module *cam_mod =
+               container_of(ref, struct gb_camera_module, refcount);
+       kfree(cam_mod->priv);
+}
+
+static int gb_camera_probe(struct gb_bundle *bundle,
+                          const struct greybus_bundle_id *id)
+{
+       struct gb_connection *conn;
+       struct gb_camera *gcam;
+       u16 mgmt_cport_id = 0;
+       u16 data_cport_id = 0;
+       unsigned int i;
+       int ret;
+
+       /*
+        * The camera bundle must contain exactly two CPorts, one for the
+        * camera management protocol and one for the camera data protocol.
+        */
+       if (bundle->num_cports != 2)
+               return -ENODEV;
+
+       for (i = 0; i < bundle->num_cports; ++i) {
+               struct greybus_descriptor_cport *desc = &bundle->cport_desc[i];
+
+               switch (desc->protocol_id) {
+               case GREYBUS_PROTOCOL_CAMERA_MGMT:
+                       mgmt_cport_id = le16_to_cpu(desc->id);
+                       break;
+               case GREYBUS_PROTOCOL_CAMERA_DATA:
+                       data_cport_id = le16_to_cpu(desc->id);
+                       break;
+               default:
+                       return -ENODEV;
+               }
+       }
+
+       if (!mgmt_cport_id || !data_cport_id)
+               return -ENODEV;
+
+       gcam = kzalloc(sizeof(*gcam), GFP_KERNEL);
+       if (!gcam)
+               return -ENOMEM;
+
+       mutex_init(&gcam->mutex);
+
+       gcam->bundle = bundle;
+       gcam->state = GB_CAMERA_STATE_UNCONFIGURED;
+       gcam->data_cport_id = data_cport_id;
+
+       conn = gb_connection_create(bundle, mgmt_cport_id,
+                                   gb_camera_request_handler);
+       if (IS_ERR(conn)) {
+               ret = PTR_ERR(conn);
+               goto error;
+       }
+
+       gcam->connection = conn;
+       gb_connection_set_data(conn, gcam);
+
+       ret = gb_connection_enable(conn);
+       if (ret)
+               goto error;
+
+       ret = gb_camera_debugfs_init(gcam);
+       if (ret < 0)
+               goto error;
+
+       gcam->module.priv = gcam;
+       gcam->module.ops = &gb_cam_ops;
+       gcam->module.interface_id = gcam->connection->intf->interface_id;
+       gcam->module.release = gb_camera_release_module;
+       ret = gb_camera_register(&gcam->module);
+       if (ret < 0)
+               goto error;
+
+       greybus_set_drvdata(bundle, gcam);
+
+       gb_pm_runtime_put_autosuspend(gcam->bundle);
+
+       return 0;
+
+error:
+       gb_camera_cleanup(gcam);
+       kfree(gcam);
+       return ret;
+}
+
+static void gb_camera_disconnect(struct gb_bundle *bundle)
+{
+       struct gb_camera *gcam = greybus_get_drvdata(bundle);
+       int ret;
+
+       ret = gb_pm_runtime_get_sync(bundle);
+       if (ret)
+               gb_pm_runtime_get_noresume(bundle);
+
+       gb_camera_cleanup(gcam);
+       gb_camera_unregister(&gcam->module);
+}
+
+static const struct greybus_bundle_id gb_camera_id_table[] = {
+       { GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_CAMERA) },
+       { },
+};
+
+#ifdef CONFIG_PM
+static int gb_camera_suspend(struct device *dev)
+{
+       struct gb_bundle *bundle = to_gb_bundle(dev);
+       struct gb_camera *gcam = greybus_get_drvdata(bundle);
+
+       if (gcam->data_connection)
+               gb_connection_disable(gcam->data_connection);
+
+       gb_connection_disable(gcam->connection);
+
+       return 0;
+}
+
+static int gb_camera_resume(struct device *dev)
+{
+       struct gb_bundle *bundle = to_gb_bundle(dev);
+       struct gb_camera *gcam = greybus_get_drvdata(bundle);
+       int ret;
+
+       ret = gb_connection_enable(gcam->connection);
+       if (ret) {
+               gcam_err(gcam, "failed to enable connection: %d\n", ret);
+               return ret;
+       }
+
+       if (gcam->data_connection) {
+               ret = gb_connection_enable(gcam->data_connection);
+               if (ret) {
+                       gcam_err(gcam,
+                                "failed to enable data connection: %d\n", ret);
+                       return ret;
+               }
+       }
+
+       return 0;
+}
+#endif
+
+static const struct dev_pm_ops gb_camera_pm_ops = {
+       SET_RUNTIME_PM_OPS(gb_camera_suspend, gb_camera_resume, NULL)
+};
+
+static struct greybus_driver gb_camera_driver = {
+       .name           = "camera",
+       .probe          = gb_camera_probe,
+       .disconnect     = gb_camera_disconnect,
+       .id_table       = gb_camera_id_table,
+       .driver.pm      = &gb_camera_pm_ops,
+};
+
+module_greybus_driver(gb_camera_driver);
+
+MODULE_LICENSE("GPL v2");
--- /dev/null
+++ b/drivers/greybus/gb-camera.h
@@ -0,0 +1,127 @@
+/*
+ * Greybus Camera protocol driver.
+ *
+ * Copyright 2015 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+#ifndef __GB_CAMERA_H
+#define __GB_CAMERA_H
+
+#include <linux/v4l2-mediabus.h>
+
+/* Input flags need to be set from the caller */
+#define GB_CAMERA_IN_FLAG_TEST         (1 << 0)
+/* Output flags returned */
+#define GB_CAMERA_OUT_FLAG_ADJUSTED    (1 << 0)
+
+/**
+ * struct gb_camera_stream - Represents greybus camera stream.
+ * @width: Stream width in pixels.
+ * @height: Stream height in pixels.
+ * @pixel_code: Media bus pixel code.
+ * @vc: MIPI CSI virtual channel.
+ * @dt: MIPI CSI data types. Most formats use a single data type, in which case
+ *      the second element will be ignored.
+ * @max_size: Maximum size of a frame in bytes. The camera module guarantees
+ *            that all data between the Frame Start and Frame End packet for
+ *            the associated virtual channel and data type(s) will not exceed
+ *            this size.
+ */
+struct gb_camera_stream {
+       unsigned int width;
+       unsigned int height;
+       enum v4l2_mbus_pixelcode pixel_code;
+       unsigned int vc;
+       unsigned int dt[2];
+       unsigned int max_size;
+};
+
+/**
+ * struct gb_camera_csi_params - CSI configuration parameters
+ * @num_lanes: number of CSI data lanes
+ * @clk_freq: CSI clock frequency in Hz
+ */
+struct gb_camera_csi_params {
+       unsigned int num_lanes;
+       unsigned int clk_freq;
+};
+
+/**
+ * struct gb_camera_ops - Greybus camera operations, used by the Greybus camera
+ *                        driver to expose operations to the host camera 
driver.
+ * @capabilities: Retrieve camera capabilities and store them in the buffer
+ *                'buf' capabilities. The buffer maximum size is specified by
+ *                the caller in the 'size' parameter, and the effective
+ *                capabilities size is returned from the function. If the 
buffer
+ *                size is too small to hold the capabilities an error is
+ *                returned and the buffer is left untouched.
+ *
+ * @configure_streams: Negotiate configuration and prepare the module for video
+ *                     capture. The caller specifies the number of streams it
+ *                     requests in the 'nstreams' argument and the associated
+ *                     streams configurations in the 'streams' argument. The
+ *                     GB_CAMERA_IN_FLAG_TEST 'flag' can be set to test a
+ *                     configuration without applying it, otherwise the
+ *                     configuration is applied by the module. The module can
+ *                     decide to modify the requested configuration, including
+ *                     using a different number of streams. In that case the
+ *                     modified configuration won't be applied, the
+ *                     GB_CAMERA_OUT_FLAG_ADJUSTED 'flag' will be set upon
+ *                     return, and the modified configuration and number of
+ *                     streams stored in 'streams' and 'array'. The module
+ *                     returns its CSI-2 bus parameters in the 'csi_params'
+ *                     structure in all cases.
+ *
+ * @capture: Submit a capture request. The supplied 'request_id' must be unique
+ *           and higher than the IDs of all the previously submitted requests.
+ *           The 'streams' argument specifies which streams are affected by the
+ *           request in the form of a bitmask, with bits corresponding to the
+ *           configured streams indexes. If the request contains settings, the
+ *           'settings' argument points to the settings buffer and its size is
+ *           specified by the 'settings_size' argument. Otherwise the 
'settings'
+ *           argument should be set to NULL and 'settings_size' to 0.
+ *
+ * @flush: Flush the capture requests queue. Return the ID of the last request
+ *         that will processed by the device before it stops transmitting video
+ *         frames. All queued capture requests with IDs higher than the 
returned
+ *         ID will be dropped without being processed.
+ */
+struct gb_camera_ops {
+       ssize_t (*capabilities)(void *priv, char *buf, size_t len);
+       int (*configure_streams)(void *priv, unsigned int *nstreams,
+                       unsigned int *flags, struct gb_camera_stream *streams,
+                       struct gb_camera_csi_params *csi_params);
+       int (*capture)(void *priv, u32 request_id,
+                       unsigned int streams, unsigned int num_frames,
+                       size_t settings_size, const void *settings);
+       int (*flush)(void *priv, u32 *request_id);
+};
+
+/**
+ * struct gb_camera_module - Represents greybus camera module.
+ * @priv: Module private data, passed to all camera operations.
+ * @ops: Greybus camera operation callbacks.
+ * @interface_id: Interface id of the module.
+ * @refcount: Reference counting object.
+ * @release: Module release function.
+ * @list: List entry in the camera modules list.
+ */
+struct gb_camera_module {
+       void *priv;
+       const struct gb_camera_ops *ops;
+
+       unsigned int interface_id;
+       struct kref refcount;
+       void (*release)(struct kref *kref);
+       struct list_head list; /* Global list */
+};
+
+#define gb_camera_call(f, op, args...)      \
+       (!(f) ? -ENODEV : (((f)->ops->op) ?  \
+       (f)->ops->op((f)->priv, ##args) : -ENOIOCTLCMD))
+
+int gb_camera_register(struct gb_camera_module *module);
+int gb_camera_unregister(struct gb_camera_module *module);
+
+#endif /* __GB_CAMERA_H */


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