This driver implements the Greybus bridged phy i2c class protocol.
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/greybus/i2c.c | 343 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 343 insertions(+)
--- /dev/null
+++ b/drivers/greybus/i2c.c
@@ -0,0 +1,343 @@
+/*
+ * I2C bridge driver for the Greybus "generic" I2C module.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#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 exit_connection_disable;
+
+ gbphy_runtime_put_autosuspend(gbphy_dev);
+ return 0;
+
+exit_connection_disable:
+ gb_connection_disable(connection);
+exit_connection_destroy:
+ gb_connection_destroy(connection);
+exit_i2cdev_free:
+ kfree(gb_i2c_dev);
+
+ return ret;
+}
+
+static void gb_i2c_remove(struct gbphy_device *gbphy_dev)
+{
+ struct gb_i2c_device *gb_i2c_dev = gb_gbphy_get_data(gbphy_dev);
+ struct gb_connection *connection = gb_i2c_dev->connection;
+ int ret;
+
+ ret = gbphy_runtime_get_sync(gbphy_dev);
+ if (ret)
+ gbphy_runtime_get_noresume(gbphy_dev);
+
+ i2c_del_adapter(&gb_i2c_dev->adapter);
+ gb_connection_disable(connection);
+ gb_connection_destroy(connection);
+ kfree(gb_i2c_dev);
+}
+
+static const struct gbphy_device_id gb_i2c_id_table[] = {
+ { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_I2C) },
+ { },
+};
+MODULE_DEVICE_TABLE(gbphy, gb_i2c_id_table);
+
+static struct gbphy_driver i2c_driver = {
+ .name = "i2c",
+ .probe = gb_i2c_probe,
+ .remove = gb_i2c_remove,
+ .id_table = gb_i2c_id_table,
+};
+
+module_gbphy_driver(i2c_driver);
+MODULE_LICENSE("GPL v2");
