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// SPDX-License-Identifier: GPL-2.0
/*
* I2C bridge driver for the Greybus "generic" I2C module.
*
* Copyright 2014 Google Inc.
* Copyright 2014 Linaro Ltd.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include "greybus.h"
#include "gbphy.h"
struct gb_i2c_device {
struct gb_connection *connection;
struct gbphy_device *gbphy_dev;
u32 functionality;
struct i2c_adapter adapter;
};
/*
* Map Greybus i2c functionality bits into Linux ones
*/
static u32 gb_i2c_functionality_map(u32 gb_i2c_functionality)
{
return gb_i2c_functionality; /* All bits the same for now */
}
static int gb_i2c_functionality_operation(struct gb_i2c_device *gb_i2c_dev)
{
struct gb_i2c_functionality_response response;
u32 functionality;
int ret;
ret = gb_operation_sync(gb_i2c_dev->connection,
GB_I2C_TYPE_FUNCTIONALITY,
NULL, 0, &response, sizeof(response));
if (ret)
return ret;
functionality = le32_to_cpu(response.functionality);
gb_i2c_dev->functionality = gb_i2c_functionality_map(functionality);
return 0;
}
/*
* Map Linux i2c_msg flags into Greybus i2c transfer op flags.
*/
static u16 gb_i2c_transfer_op_flags_map(u16 flags)
{
return flags; /* All flags the same for now */
}
static void
gb_i2c_fill_transfer_op(struct gb_i2c_transfer_op *op, struct i2c_msg *msg)
{
u16 flags = gb_i2c_transfer_op_flags_map(msg->flags);
op->addr = cpu_to_le16(msg->addr);
op->flags = cpu_to_le16(flags);
op->size = cpu_to_le16(msg->len);
}
static struct gb_operation *
gb_i2c_operation_create(struct gb_connection *connection,
struct i2c_msg *msgs, u32 msg_count)
{
struct gb_i2c_device *gb_i2c_dev = gb_connection_get_data(connection);
struct gb_i2c_transfer_request *request;
struct gb_operation *operation;
struct gb_i2c_transfer_op *op;
struct i2c_msg *msg;
u32 data_out_size = 0;
u32 data_in_size = 0;
size_t request_size;
void *data;
u16 op_count;
u32 i;
if (msg_count > (u32)U16_MAX) {
dev_err(&gb_i2c_dev->gbphy_dev->dev, "msg_count (%u) too big\n",
msg_count);
return NULL;
}
op_count = (u16)msg_count;
/*
* In addition to space for all message descriptors we need
* to have enough to hold all outbound message data.
*/
msg = msgs;
for (i = 0; i < msg_count; i++, msg++)
if (msg->flags & I2C_M_RD)
data_in_size += (u32)msg->len;
else
data_out_size += (u32)msg->len;
request_size = sizeof(*request);
request_size += msg_count * sizeof(*op);
request_size += data_out_size;
/* Response consists only of incoming data */
operation = gb_operation_create(connection, GB_I2C_TYPE_TRANSFER,
request_size, data_in_size, GFP_KERNEL);
if (!operation)
return NULL;
request = operation->request->payload;
request->op_count = cpu_to_le16(op_count);
/* Fill in the ops array */
op = &request->ops[0];
msg = msgs;
for (i = 0; i < msg_count; i++)
gb_i2c_fill_transfer_op(op++, msg++);
if (!data_out_size)
return operation;
/* Copy over the outgoing data; it starts after the last op */
data = op;
msg = msgs;
for (i = 0; i < msg_count; i++) {
if (!(msg->flags & I2C_M_RD)) {
memcpy(data, msg->buf, msg->len);
data += msg->len;
}
msg++;
}
return operation;
}
static void gb_i2c_decode_response(struct i2c_msg *msgs, u32 msg_count,
struct gb_i2c_transfer_response *response)
{
struct i2c_msg *msg = msgs;
u8 *data;
u32 i;
if (!response)
return;
data = response->data;
for (i = 0; i < msg_count; i++) {
if (msg->flags & I2C_M_RD) {
memcpy(msg->buf, data, msg->len);
data += msg->len;
}
msg++;
}
}
/*
* Some i2c transfer operations return results that are expected.
*/
static bool gb_i2c_expected_transfer_error(int errno)
{
return errno == -EAGAIN || errno == -ENODEV;
}
static int gb_i2c_transfer_operation(struct gb_i2c_device *gb_i2c_dev,
struct i2c_msg *msgs, u32 msg_count)
{
struct gb_connection *connection = gb_i2c_dev->connection;
struct device *dev = &gb_i2c_dev->gbphy_dev->dev;
struct gb_operation *operation;
int ret;
operation = gb_i2c_operation_create(connection, msgs, msg_count);
if (!operation)
return -ENOMEM;
ret = gbphy_runtime_get_sync(gb_i2c_dev->gbphy_dev);
if (ret)
goto exit_operation_put;
ret = gb_operation_request_send_sync(operation);
if (!ret) {
struct gb_i2c_transfer_response *response;
response = operation->response->payload;
gb_i2c_decode_response(msgs, msg_count, response);
ret = msg_count;
} else if (!gb_i2c_expected_transfer_error(ret)) {
dev_err(dev, "transfer operation failed (%d)\n", ret);
}
gbphy_runtime_put_autosuspend(gb_i2c_dev->gbphy_dev);
exit_operation_put:
gb_operation_put(operation);
return ret;
}
static int gb_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int msg_count)
{
struct gb_i2c_device *gb_i2c_dev;
gb_i2c_dev = i2c_get_adapdata(adap);
return gb_i2c_transfer_operation(gb_i2c_dev, msgs, msg_count);
}
#if 0
/* Later */
static int gb_i2c_smbus_xfer(struct i2c_adapter *adap,
u16 addr, unsigned short flags, char read_write,
u8 command, int size, union i2c_smbus_data *data)
{
struct gb_i2c_device *gb_i2c_dev;
gb_i2c_dev = i2c_get_adapdata(adap);
return 0;
}
#endif
static u32 gb_i2c_functionality(struct i2c_adapter *adap)
{
struct gb_i2c_device *gb_i2c_dev = i2c_get_adapdata(adap);
return gb_i2c_dev->functionality;
}
static const struct i2c_algorithm gb_i2c_algorithm = {
.master_xfer = gb_i2c_master_xfer,
/* .smbus_xfer = gb_i2c_smbus_xfer, */
.functionality = gb_i2c_functionality,
};
/*
* Do initial setup of the i2c device. This includes verifying we
* can support it (based on the protocol version it advertises).
* If that's OK, we get and cached its functionality bits.
*
* Note: gb_i2c_dev->connection is assumed to have been valid.
*/
static int gb_i2c_device_setup(struct gb_i2c_device *gb_i2c_dev)
{
/* Assume the functionality never changes, just get it once */
return gb_i2c_functionality_operation(gb_i2c_dev);
}
static int gb_i2c_probe(struct gbphy_device *gbphy_dev,
const struct gbphy_device_id *id)
{
struct gb_connection *connection;
struct gb_i2c_device *gb_i2c_dev;
struct i2c_adapter *adapter;
int ret;
gb_i2c_dev = kzalloc(sizeof(*gb_i2c_dev), GFP_KERNEL);
if (!gb_i2c_dev)
return -ENOMEM;
connection =
gb_connection_create(gbphy_dev->bundle,
le16_to_cpu(gbphy_dev->cport_desc->id),
NULL);
if (IS_ERR(connection)) {
ret = PTR_ERR(connection);
goto exit_i2cdev_free;
}
gb_i2c_dev->connection = connection;
gb_connection_set_data(connection, gb_i2c_dev);
gb_i2c_dev->gbphy_dev = gbphy_dev;
gb_gbphy_set_data(gbphy_dev, gb_i2c_dev);
ret = gb_connection_enable(connection);
if (ret)
goto exit_connection_destroy;
ret = gb_i2c_device_setup(gb_i2c_dev);
if (ret)
goto exit_connection_disable;
/* Looks good; up our i2c adapter */
adapter = &gb_i2c_dev->adapter;
adapter->owner = THIS_MODULE;
adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
adapter->algo = &gb_i2c_algorithm;
/* adapter->algo_data = what? */
adapter->dev.parent = &gbphy_dev->dev;
snprintf(adapter->name, sizeof(adapter->name), "Greybus i2c adapter");
i2c_set_adapdata(adapter, gb_i2c_dev);
ret = i2c_add_adapter(adapter);
if (ret)
goto
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