SMBus Host-Notify protocol, from the adapter point of view consist of receiving a message from a client, including the client address and some other data.
It can be simply handled by creating a new slave device and registering a callback performing the parsing of the message received from the client. This commit introduces two new core functions * i2c_new_smbus_host_notify_device * i2c_free_smbus_host_notify_device that take care of registration of the new slave device and callback and will call i2c_handle_smbus_host_notify once a Host-Notify event is received. Signed-off-by: Alain Volmat <alain.vol...@st.com> --- drivers/i2c/i2c-core-smbus.c | 105 +++++++++++++++++++++++++++++++++++ include/linux/i2c-smbus.h | 2 + 2 files changed, 107 insertions(+) diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c index b34d2ff06931..0c7e135c73e1 100644 --- a/drivers/i2c/i2c-core-smbus.c +++ b/drivers/i2c/i2c-core-smbus.c @@ -708,3 +708,108 @@ int of_i2c_setup_smbus_alert(struct i2c_adapter *adapter) } EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert); #endif + +struct i2c_smbus_host_notify_status { + bool notify_start; + u8 addr; +}; + +static int i2c_smbus_host_notify_cb(struct i2c_client *client, + enum i2c_slave_event event, u8 *val) +{ + struct i2c_smbus_host_notify_status *status = client->dev.platform_data; + int ret; + + switch (event) { + case I2C_SLAVE_WRITE_REQUESTED: + status->notify_start = true; + break; + case I2C_SLAVE_WRITE_RECEIVED: + /* We only retrieve the first byte received (addr) + * since there is currently no way to retrieve the data + * parameter from the client. + */ + if (!status->notify_start) + break; + status->addr = *val; + status->notify_start = false; + break; + case I2C_SLAVE_STOP: + ret = i2c_handle_smbus_host_notify(client->adapter, + status->addr); + if (ret < 0) { + dev_warn(&client->adapter->dev, "failed to handle host_notify (%d)\n", + ret); + return ret; + } + break; + default: + /* Only handle necessary events */ + break; + } + + return 0; +} + +/** + * i2c_new_smbus_host_notify_device - get a client for SMBus host-notify support + * @adapter: the target adapter + * Context: can sleep + * + * Setup handling of the SMBus host-notify protocol on a given I2C bus segment. + * + * Handling is done by creating a device and its callback and handling data + * received via the SMBus host-notify address (0x8) + * + * This returns the client, which should be ultimately freed using + * i2c_free_smbus_host_notify_device(); or an ERRPTR to indicate an error. + */ +struct i2c_client *i2c_new_smbus_host_notify_device(struct i2c_adapter *adapter) +{ + struct i2c_board_info host_notify_board_info = { + I2C_BOARD_INFO("smbus_host_notify", 0x08), + .flags = I2C_CLIENT_SLAVE, + }; + struct i2c_smbus_host_notify_status *status; + struct i2c_client *client; + int ret; + + status = kzalloc(sizeof(struct i2c_smbus_host_notify_status), + GFP_KERNEL); + if (!status) + return ERR_PTR(-ENOMEM); + + host_notify_board_info.platform_data = status; + + client = i2c_new_client_device(adapter, &host_notify_board_info); + if (IS_ERR(client)) { + kfree(status); + return client; + } + + ret = i2c_slave_register(client, i2c_smbus_host_notify_cb); + if (ret) { + i2c_unregister_device(client); + kfree(status); + return ERR_PTR(ret); + } + + return client; +} +EXPORT_SYMBOL_GPL(i2c_new_smbus_host_notify_device); + +/** + * i2c_free_smbus_host_notify_device - free the client for SMBus host-notify + * support + * @client: the client to free + * Context: can sleep + * + * Free the i2c_client allocated via i2c_new_smbus_host_notify_device + */ +void i2c_free_smbus_host_notify_device(struct i2c_client *client) +{ + i2c_slave_unregister(client); + kfree(client->dev.platform_data); + i2c_unregister_device(client); +} +EXPORT_SYMBOL_GPL(i2c_free_smbus_host_notify_device); diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h index 8c5459034f92..926f6d8ae30d 100644 --- a/include/linux/i2c-smbus.h +++ b/include/linux/i2c-smbus.h @@ -38,5 +38,7 @@ static inline int of_i2c_setup_smbus_alert(struct i2c_adapter *adap) return 0; } #endif +struct i2c_client *i2c_new_smbus_host_notify_device(struct i2c_adapter *adapter); +void i2c_free_smbus_host_notify_device(struct i2c_client *client); #endif /* _LINUX_I2C_SMBUS_H */ -- 2.17.1