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453bbea807
In order to facilitate re-use of the gpio, i2c, pwm and i2s structures, split them out of independent files and add them into a shared gpbridge.h This will be a prereq to sharing these headers w/ gbsim. Cc: Alex Elder <alex.elder@linaro.org> Cc: Greg Kroah-Hartman <gregkh@google.com> CC: Johan Hovold <johan@hovoldconsulting.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
369 lines
8.5 KiB
C
369 lines
8.5 KiB
C
/*
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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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* Released under the GPLv2 only.
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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 "greybus.h"
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#include "gpbridge.h"
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struct gb_i2c_device {
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struct gb_connection *connection;
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u8 version_major;
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u8 version_minor;
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u32 functionality;
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u16 timeout_msec;
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u8 retries;
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struct i2c_adapter adapter;
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};
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/* Define get_version() routine */
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define_get_version(gb_i2c_device, I2C);
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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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static int gb_i2c_functionality_operation(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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static int gb_i2c_timeout_operation(struct gb_i2c_device *gb_i2c_dev, u16 msec)
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{
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struct gb_i2c_timeout_request request;
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int ret;
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request.msec = cpu_to_le16(msec);
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ret = gb_operation_sync(gb_i2c_dev->connection, GB_I2C_TYPE_TIMEOUT,
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&request, sizeof(request), NULL, 0);
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if (ret)
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pr_err("timeout operation failed (%d)\n", ret);
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else
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gb_i2c_dev->timeout_msec = msec;
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return ret;
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}
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static int gb_i2c_retries_operation(struct gb_i2c_device *gb_i2c_dev,
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u8 retries)
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{
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struct gb_i2c_retries_request request;
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int ret;
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request.retries = retries;
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ret = gb_operation_sync(gb_i2c_dev->connection, GB_I2C_TYPE_RETRIES,
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&request, sizeof(request), NULL, 0);
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if (ret)
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pr_err("retries operation failed (%d)\n", ret);
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else
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gb_i2c_dev->retries = retries;
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return ret;
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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_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(&connection->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);
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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 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 = 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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pr_err("transfer operation failed (%d)\n", ret);
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}
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gb_operation_destroy(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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#if 0
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/* Later */
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static int gb_i2c_smbus_xfer(struct i2c_adapter *adap,
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u16 addr, unsigned short flags, char read_write,
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u8 command, int size, union i2c_smbus_data *data)
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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 0;
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}
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#endif
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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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/* .smbus_xfer = gb_i2c_smbus_xfer, */
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.functionality = gb_i2c_functionality,
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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, and
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* set up the retry count and timeout.
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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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int ret;
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/* First thing we need to do is check the version */
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ret = get_version(gb_i2c_dev);
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if (ret)
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return ret;
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/* Assume the functionality never changes, just get it once */
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ret = gb_i2c_functionality_operation(gb_i2c_dev);
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if (ret)
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return ret;
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/* Set up our default retry count and timeout */
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ret = gb_i2c_retries_operation(gb_i2c_dev, GB_I2C_RETRIES_DEFAULT);
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if (ret)
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return ret;
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return gb_i2c_timeout_operation(gb_i2c_dev, GB_I2C_TIMEOUT_DEFAULT);
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}
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static int gb_i2c_connection_init(struct gb_connection *connection)
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{
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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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gb_i2c_dev->connection = connection; /* refcount? */
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connection->private = gb_i2c_dev;
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ret = gb_i2c_device_setup(gb_i2c_dev);
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if (ret)
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goto out_err;
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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->algo_data = what? */
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adapter->timeout = gb_i2c_dev->timeout_msec * HZ / 1000;
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adapter->retries = gb_i2c_dev->retries;
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adapter->dev.parent = &connection->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 out_err;
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return 0;
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out_err:
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/* kref_put(gb_i2c_dev->connection) */
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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_connection_exit(struct gb_connection *connection)
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{
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struct gb_i2c_device *gb_i2c_dev = connection->private;
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i2c_del_adapter(&gb_i2c_dev->adapter);
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/* kref_put(gb_i2c_dev->connection) */
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kfree(gb_i2c_dev);
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}
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static struct gb_protocol i2c_protocol = {
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.name = "i2c",
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.id = GREYBUS_PROTOCOL_I2C,
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.major = 0,
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.minor = 1,
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.connection_init = gb_i2c_connection_init,
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.connection_exit = gb_i2c_connection_exit,
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.request_recv = NULL, /* no incoming requests */
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};
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int gb_i2c_protocol_init(void)
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{
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return gb_protocol_register(&i2c_protocol);
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}
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void gb_i2c_protocol_exit(void)
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{
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gb_protocol_deregister(&i2c_protocol);
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}
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