SMBus Host Notify allows a slave device to act as a master on a bus to notify the host of an interrupt. On Intel chipsets, the functionality is directly implemented in the firmware. We just need to export a function to call .alert() on the proper device driver.
Compared to i2c_handle_smbus_alert(), it is much more convenient to require to be able to sleep in i2c_propagate_smbus_host_notify(). device_(un)lock() in smbus_do_alert() needs to be able to sleep, but because the address and payload are given directly by the caller scheduling a new task would require a fifo or a lock on the current I2C address and payload. Signed-off-by: Benjamin Tissoires <[email protected]> --- Changes in v2: - do the actual processing of finding the device in i2c-smbus.c - remove the i2c-core implementations - remove the manual toggle of SMBus Host Notify Documentation/i2c/smbus-protocol | 3 +++ drivers/i2c/i2c-smbus.c | 36 +++++++++++++++++++++++++++++++----- include/linux/i2c-smbus.h | 8 ++++++++ include/linux/i2c.h | 3 +++ include/uapi/linux/i2c.h | 1 + 5 files changed, 46 insertions(+), 5 deletions(-) diff --git a/Documentation/i2c/smbus-protocol b/Documentation/i2c/smbus-protocol index 6012b12..4e07848 100644 --- a/Documentation/i2c/smbus-protocol +++ b/Documentation/i2c/smbus-protocol @@ -199,6 +199,9 @@ alerting device's address. [S] [HostAddr] [Wr] A [DevAddr] A [DataLow] A [DataHigh] A [P] +I2C drivers for devices which can trigger SMBus Host Notify should implement +the optional alert() callback. + Packet Error Checking (PEC) =========================== diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c index abad351..c348c1a 100644 --- a/drivers/i2c/i2c-smbus.c +++ b/drivers/i2c/i2c-smbus.c @@ -33,7 +33,8 @@ struct i2c_smbus_alert { struct alert_data { unsigned short addr; - u8 flag:1; + enum i2c_alert_protocol type; + unsigned int data; }; /* If this is the alerting device, notify its driver */ @@ -56,8 +57,7 @@ static int smbus_do_alert(struct device *dev, void *addrp) if (client->dev.driver) { driver = to_i2c_driver(client->dev.driver); if (driver->alert) - driver->alert(client, I2C_PROTOCOL_SMBUS_ALERT, - data->flag); + driver->alert(client, data->type, data->data); else dev_warn(&client->dev, "no driver alert()!\n"); } else @@ -97,8 +97,9 @@ static void smbus_alert(struct work_struct *work) if (status < 0) break; - data.flag = status & 1; + data.data = status & 1; data.addr = status >> 1; + data.type = I2C_PROTOCOL_SMBUS_ALERT; if (data.addr == prev_addr) { dev_warn(&ara->dev, "Duplicate SMBALERT# from dev " @@ -106,7 +107,7 @@ static void smbus_alert(struct work_struct *work) break; } dev_dbg(&ara->dev, "SMBALERT# from dev 0x%02x, flag %d\n", - data.addr, data.flag); + data.addr, data.data); /* Notify driver for the device which issued the alert */ device_for_each_child(&ara->adapter->dev, &data, @@ -240,6 +241,31 @@ int i2c_handle_smbus_alert(struct i2c_client *ara) } EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert); +/** + * i2c_propagate_smbus_host_notify - Forward a Host Notify event to the correct + * I2C client. + * @adapter: the adapter that triggered the Host Notify event + * @data: the Host Notify data which contains the payload and address of the + * client + * Context: Must be able to sleep + * + * Helper function to be called from an I2C bus driver's interrupt + * handler that can sleep. It will call the Host Notify callback of the I2C + * device driver if it is found on the adapter. + */ +void i2c_propagate_smbus_host_notify(struct i2c_adapter *adapter, + unsigned short addr, unsigned int data) +{ + struct alert_data alert = { + .type = I2C_PROTOCOL_SMBUS_HOST_NOTIFY, + .addr = addr, + .data = data, + }; + + device_for_each_child(&adapter->dev, &alert, smbus_do_alert); +} +EXPORT_SYMBOL_GPL(i2c_propagate_smbus_host_notify); + module_i2c_driver(smbalert_driver); MODULE_AUTHOR("Jean Delvare <[email protected]>"); diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h index 8f1b086..285efe05 100644 --- a/include/linux/i2c-smbus.h +++ b/include/linux/i2c-smbus.h @@ -48,4 +48,12 @@ struct i2c_client *i2c_setup_smbus_alert(struct i2c_adapter *adapter, struct i2c_smbus_alert_setup *setup); int i2c_handle_smbus_alert(struct i2c_client *ara); +#if defined(CONFIG_I2C_SMBUS) || defined(CONFIG_I2C_SMBUS_MODULE) +void i2c_propagate_smbus_host_notify(struct i2c_adapter *adapter, + unsigned short addr, unsigned int data); +#else +static inline void i2c_propagate_smbus_host_notify(struct i2c_adapter *adapter, + unsigned short addr, unsigned int data) {} +#endif /* I2C_SMBUS */ + #endif /* _LINUX_I2C_SMBUS_H */ diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 6764734..81344d3 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -125,6 +125,7 @@ extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, enum i2c_alert_protocol { I2C_PROTOCOL_SMBUS_ALERT, + I2C_PROTOCOL_SMBUS_HOST_NOTIFY, }; /** @@ -181,6 +182,8 @@ struct i2c_driver { * The format and meaning of the data value depends on the protocol. * For the SMBus alert protocol, there is a single bit of data passed * as the alert response's low bit ("event flag"). + * For the SMBus Host Notify protocol, the data corresponds to the + * 16-bit payload data reported by the slave device acting as master. */ void (*alert)(struct i2c_client *, enum i2c_alert_protocol protocol, unsigned int data); diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h index b0a7dd6..83ec8ae 100644 --- a/include/uapi/linux/i2c.h +++ b/include/uapi/linux/i2c.h @@ -101,6 +101,7 @@ struct i2c_msg { #define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000 #define I2C_FUNC_SMBUS_READ_I2C_BLOCK 0x04000000 /* I2C-like block xfer */ #define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK 0x08000000 /* w/ 1-byte reg. addr. */ +#define I2C_FUNC_SMBUS_HOST_NOTIFY 0x10000000 #define I2C_FUNC_SMBUS_BYTE (I2C_FUNC_SMBUS_READ_BYTE | \ I2C_FUNC_SMBUS_WRITE_BYTE) -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
