// SPDX-License-Identifier: GPL-2.0
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/*
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* I2C bridge driver for the Greybus "generic" I2C module.
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*
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* Copyright 2014 Google Inc.
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* Copyright 2014 Linaro Ltd.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include <linux/greybus.h>
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#include "gbphy.h"
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struct gb_i2c_device {
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struct gb_connection *connection;
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struct gbphy_device *gbphy_dev;
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u32 functionality;
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struct i2c_adapter adapter;
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};
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/*
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* Map Greybus i2c functionality bits into Linux ones
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*/
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static u32 gb_i2c_functionality_map(u32 gb_i2c_functionality)
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{
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return gb_i2c_functionality; /* All bits the same for now */
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}
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/*
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* Do initial setup of the i2c device. This includes verifying we
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* can support it (based on the protocol version it advertises).
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* If that's OK, we get and cached its functionality bits.
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*
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* Note: gb_i2c_dev->connection is assumed to have been valid.
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*/
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static int gb_i2c_device_setup(struct gb_i2c_device *gb_i2c_dev)
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{
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struct gb_i2c_functionality_response response;
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u32 functionality;
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int ret;
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ret = gb_operation_sync(gb_i2c_dev->connection,
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GB_I2C_TYPE_FUNCTIONALITY,
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NULL, 0, &response, sizeof(response));
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if (ret)
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return ret;
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functionality = le32_to_cpu(response.functionality);
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gb_i2c_dev->functionality = gb_i2c_functionality_map(functionality);
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return 0;
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}
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/*
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* Map Linux i2c_msg flags into Greybus i2c transfer op flags.
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*/
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static u16 gb_i2c_transfer_op_flags_map(u16 flags)
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{
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return flags; /* All flags the same for now */
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}
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static void
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gb_i2c_fill_transfer_op(struct gb_i2c_transfer_op *op, struct i2c_msg *msg)
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{
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u16 flags = gb_i2c_transfer_op_flags_map(msg->flags);
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op->addr = cpu_to_le16(msg->addr);
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op->flags = cpu_to_le16(flags);
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op->size = cpu_to_le16(msg->len);
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}
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static struct gb_operation *
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gb_i2c_operation_create(struct gb_connection *connection,
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struct i2c_msg *msgs, u32 msg_count)
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{
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struct gb_i2c_device *gb_i2c_dev = gb_connection_get_data(connection);
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struct gb_i2c_transfer_request *request;
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struct gb_operation *operation;
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struct gb_i2c_transfer_op *op;
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struct i2c_msg *msg;
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u32 data_out_size = 0;
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u32 data_in_size = 0;
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size_t request_size;
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void *data;
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u16 op_count;
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u32 i;
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if (msg_count > (u32)U16_MAX) {
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dev_err(&gb_i2c_dev->gbphy_dev->dev, "msg_count (%u) too big\n",
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msg_count);
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return NULL;
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}
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op_count = (u16)msg_count;
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/*
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* In addition to space for all message descriptors we need
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* to have enough to hold all outbound message data.
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*/
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msg = msgs;
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for (i = 0; i < msg_count; i++, msg++)
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if (msg->flags & I2C_M_RD)
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data_in_size += (u32)msg->len;
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else
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data_out_size += (u32)msg->len;
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request_size = sizeof(*request);
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request_size += msg_count * sizeof(*op);
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request_size += data_out_size;
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/* Response consists only of incoming data */
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operation = gb_operation_create(connection, GB_I2C_TYPE_TRANSFER,
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request_size, data_in_size, GFP_KERNEL);
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if (!operation)
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return NULL;
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request = operation->request->payload;
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request->op_count = cpu_to_le16(op_count);
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/* Fill in the ops array */
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op = &request->ops[0];
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msg = msgs;
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for (i = 0; i < msg_count; i++)
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gb_i2c_fill_transfer_op(op++, msg++);
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if (!data_out_size)
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return operation;
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/* Copy over the outgoing data; it starts after the last op */
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data = op;
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msg = msgs;
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for (i = 0; i < msg_count; i++) {
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if (!(msg->flags & I2C_M_RD)) {
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memcpy(data, msg->buf, msg->len);
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data += msg->len;
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}
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msg++;
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}
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return operation;
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}
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static void gb_i2c_decode_response(struct i2c_msg *msgs, u32 msg_count,
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struct gb_i2c_transfer_response *response)
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{
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struct i2c_msg *msg = msgs;
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u8 *data;
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u32 i;
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if (!response)
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return;
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data = response->data;
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for (i = 0; i < msg_count; i++) {
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if (msg->flags & I2C_M_RD) {
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memcpy(msg->buf, data, msg->len);
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data += msg->len;
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}
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msg++;
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}
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}
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/*
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* Some i2c transfer operations return results that are expected.
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*/
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static bool gb_i2c_expected_transfer_error(int errno)
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{
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return errno == -EAGAIN || errno == -ENODEV;
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}
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static int gb_i2c_transfer_operation(struct gb_i2c_device *gb_i2c_dev,
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struct i2c_msg *msgs, u32 msg_count)
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{
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struct gb_connection *connection = gb_i2c_dev->connection;
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struct device *dev = &gb_i2c_dev->gbphy_dev->dev;
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struct gb_operation *operation;
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int ret;
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operation = gb_i2c_operation_create(connection, msgs, msg_count);
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if (!operation)
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return -ENOMEM;
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ret = gbphy_runtime_get_sync(gb_i2c_dev->gbphy_dev);
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if (ret)
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goto exit_operation_put;
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ret = gb_operation_request_send_sync(operation);
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if (!ret) {
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struct gb_i2c_transfer_response *response;
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response = operation->response->payload;
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gb_i2c_decode_response(msgs, msg_count, response);
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ret = msg_count;
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} else if (!gb_i2c_expected_transfer_error(ret)) {
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dev_err(dev, "transfer operation failed (%d)\n", ret);
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}
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gbphy_runtime_put_autosuspend(gb_i2c_dev->gbphy_dev);
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exit_operation_put:
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gb_operation_put(operation);
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return ret;
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}
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static int gb_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
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int msg_count)
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{
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struct gb_i2c_device *gb_i2c_dev;
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gb_i2c_dev = i2c_get_adapdata(adap);
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return gb_i2c_transfer_operation(gb_i2c_dev, msgs, msg_count);
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}
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static u32 gb_i2c_functionality(struct i2c_adapter *adap)
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{
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struct gb_i2c_device *gb_i2c_dev = i2c_get_adapdata(adap);
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return gb_i2c_dev->functionality;
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}
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static const struct i2c_algorithm gb_i2c_algorithm = {
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.master_xfer = gb_i2c_master_xfer,
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.functionality = gb_i2c_functionality,
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};
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static int gb_i2c_probe(struct gbphy_device *gbphy_dev,
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const struct gbphy_device_id *id)
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{
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struct gb_connection *connection;
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struct gb_i2c_device *gb_i2c_dev;
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struct i2c_adapter *adapter;
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int ret;
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gb_i2c_dev = kzalloc(sizeof(*gb_i2c_dev), GFP_KERNEL);
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if (!gb_i2c_dev)
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return -ENOMEM;
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connection =
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gb_connection_create(gbphy_dev->bundle,
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le16_to_cpu(gbphy_dev->cport_desc->id),
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NULL);
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if (IS_ERR(connection)) {
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ret = PTR_ERR(connection);
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goto exit_i2cdev_free;
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}
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gb_i2c_dev->connection = connection;
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gb_connection_set_data(connection, gb_i2c_dev);
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gb_i2c_dev->gbphy_dev = gbphy_dev;
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gb_gbphy_set_data(gbphy_dev, gb_i2c_dev);
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ret = gb_connection_enable(connection);
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if (ret)
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goto exit_connection_destroy;
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ret = gb_i2c_device_setup(gb_i2c_dev);
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if (ret)
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goto exit_connection_disable;
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/* Looks good; up our i2c adapter */
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adapter = &gb_i2c_dev->adapter;
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adapter->owner = THIS_MODULE;
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adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
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adapter->algo = &gb_i2c_algorithm;
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adapter->dev.parent = &gbphy_dev->dev;
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snprintf(adapter->name, sizeof(adapter->name), "Greybus i2c adapter");
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i2c_set_adapdata(adapter, gb_i2c_dev);
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ret = i2c_add_adapter(adapter);
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if (ret)
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goto exit_connection_disable;
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gbphy_runtime_put_autosuspend(gbphy_dev);
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return 0;
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exit_connection_disable:
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gb_connection_disable(connection);
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exit_connection_destroy:
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gb_connection_destroy(connection);
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exit_i2cdev_free:
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kfree(gb_i2c_dev);
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return ret;
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}
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static void gb_i2c_remove(struct gbphy_device *gbphy_dev)
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{
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struct gb_i2c_device *gb_i2c_dev = gb_gbphy_get_data(gbphy_dev);
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struct gb_connection *connection = gb_i2c_dev->connection;
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int ret;
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ret = gbphy_runtime_get_sync(gbphy_dev);
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if (ret)
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gbphy_runtime_get_noresume(gbphy_dev);
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i2c_del_adapter(&gb_i2c_dev->adapter);
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gb_connection_disable(connection);
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gb_connection_destroy(connection);
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kfree(gb_i2c_dev);
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}
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static const struct gbphy_device_id gb_i2c_id_table[] = {
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{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_I2C) },
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{ },
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};
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MODULE_DEVICE_TABLE(gbphy, gb_i2c_id_table);
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static struct gbphy_driver i2c_driver = {
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.name = "i2c",
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.probe = gb_i2c_probe,
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.remove = gb_i2c_remove,
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.id_table = gb_i2c_id_table,
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};
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module_gbphy_driver(i2c_driver);
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MODULE_LICENSE("GPL v2");
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