diff options
| -rw-r--r-- | Documentation/i2c/smbus-protocol | 6 | ||||
| -rw-r--r-- | drivers/i2c/i2c-smbus.c | 113 | ||||
| -rw-r--r-- | include/linux/i2c-smbus.h | 44 | ||||
| -rw-r--r-- | include/linux/i2c.h | 3 | ||||
| -rw-r--r-- | include/uapi/linux/i2c.h | 1 |
5 files changed, 162 insertions, 5 deletions
diff --git a/Documentation/i2c/smbus-protocol b/Documentation/i2c/smbus-protocol index 6012b12b3510..14d4ec1be245 100644 --- a/Documentation/i2c/smbus-protocol +++ b/Documentation/i2c/smbus-protocol @@ -199,6 +199,12 @@ alerting device's address. [S] [HostAddr] [Wr] A [DevAddr] A [DataLow] A [DataHigh] A [P] +This is implemented in the following way in the Linux kernel: +* I2C bus drivers which support SMBus Host Notify should call + i2c_setup_smbus_host_notify() to setup SMBus Host Notify support. +* 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 3b6765a4ebe9..f574995b41c1 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 +241,108 @@ int i2c_handle_smbus_alert(struct i2c_client *ara) } EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert); +static void smbus_host_notify_work(struct work_struct *work) +{ + struct alert_data alert; + struct i2c_adapter *adapter; + unsigned long flags; + u16 payload; + u8 addr; + struct smbus_host_notify *data; + + data = container_of(work, struct smbus_host_notify, work); + + spin_lock_irqsave(&data->lock, flags); + payload = data->payload; + addr = data->addr; + adapter = data->adapter; + + /* clear the pending bit and release the spinlock */ + data->pending = false; + spin_unlock_irqrestore(&data->lock, flags); + + if (!adapter || !addr) + return; + + alert.type = I2C_PROTOCOL_SMBUS_HOST_NOTIFY; + alert.addr = addr; + alert.data = payload; + + device_for_each_child(&adapter->dev, &alert, smbus_do_alert); +} + +/** + * i2c_setup_smbus_host_notify - Allocate a new smbus_host_notify for the given + * I2C adapter. + * @adapter: the adapter we want to associate a Host Notify function + * + * Returns a struct smbus_host_notify pointer on success, and NULL on failure. + * The resulting smbus_host_notify must not be freed afterwards, it is a + * managed resource already. + */ +struct smbus_host_notify *i2c_setup_smbus_host_notify(struct i2c_adapter *adap) +{ + struct smbus_host_notify *host_notify; + + host_notify = devm_kzalloc(&adap->dev, sizeof(struct smbus_host_notify), + GFP_KERNEL); + if (!host_notify) + return NULL; + + host_notify->adapter = adap; + + spin_lock_init(&host_notify->lock); + INIT_WORK(&host_notify->work, smbus_host_notify_work); + + return host_notify; +} +EXPORT_SYMBOL_GPL(i2c_setup_smbus_host_notify); + +/** + * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct + * I2C client. + * @host_notify: the struct host_notify attached to the relevant adapter + * @data: the Host Notify data which contains the payload and address of the + * client + * Context: can't sleep + * + * Helper function to be called from an I2C bus driver's interrupt + * handler. It will schedule the Host Notify work, in turn calling the + * corresponding I2C device driver's alert function. + * + * host_notify should be a valid pointer previously returned by + * i2c_setup_smbus_host_notify(). + */ +int i2c_handle_smbus_host_notify(struct smbus_host_notify *host_notify, + unsigned short addr, unsigned int data) +{ + unsigned long flags; + struct i2c_adapter *adapter; + + if (!host_notify || !host_notify->adapter) + return -EINVAL; + + adapter = host_notify->adapter; + + spin_lock_irqsave(&host_notify->lock, flags); + + if (host_notify->pending) { + spin_unlock_irqrestore(&host_notify->lock, flags); + dev_warn(&adapter->dev, "Host Notify already scheduled.\n"); + return -EBUSY; + } + + host_notify->payload = data; + host_notify->addr = addr; + + /* Mark that there is a pending notification and release the lock */ + host_notify->pending = true; + spin_unlock_irqrestore(&host_notify->lock, flags); + + return schedule_work(&host_notify->work); +} +EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify); + module_i2c_driver(smbalert_driver); MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h index 8f1b086ca5bc..4ac95bbe53ef 100644 --- a/include/linux/i2c-smbus.h +++ b/include/linux/i2c-smbus.h @@ -23,6 +23,8 @@ #define _LINUX_I2C_SMBUS_H #include <linux/i2c.h> +#include <linux/spinlock.h> +#include <linux/workqueue.h> /** @@ -48,4 +50,46 @@ 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); +/** + * smbus_host_notify - internal structure used by the Host Notify mechanism. + * @adapter: the I2C adapter associated with this struct + * @work: worker used to schedule the IRQ in the slave device + * @lock: spinlock to check if a notification is already pending + * @pending: flag set when a notification is pending (any new notification will + * be rejected if pending is true) + * @payload: the actual payload of the Host Notify event + * @addr: the address of the slave device which raised the notification + * + * This struct needs to be allocated by i2c_setup_smbus_host_notify() and does + * not need to be freed. Internally, i2c_setup_smbus_host_notify() uses a + * managed resource to clean this up when the adapter get released. + */ +struct smbus_host_notify { + struct i2c_adapter *adapter; + struct work_struct work; + spinlock_t lock; + bool pending; + u16 payload; + u8 addr; +}; + +#if IS_ENABLED(CONFIG_I2C_SMBUS) +struct smbus_host_notify *i2c_setup_smbus_host_notify(struct i2c_adapter *adap); +int i2c_handle_smbus_host_notify(struct smbus_host_notify *host_notify, + unsigned short addr, unsigned int data); +#else +static inline struct smbus_host_notify * +i2c_setup_smbus_host_notify(struct i2c_adapter *adap) +{ + return NULL; +} + +static inline int +i2c_handle_smbus_host_notify(struct smbus_host_notify *host_notify, + unsigned short addr, unsigned int data) +{ + return 0; +} +#endif /* I2C_SMBUS */ + #endif /* _LINUX_I2C_SMBUS_H */ diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 37a45dcd6592..fffdc270ca18 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -128,6 +128,7 @@ i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client, enum i2c_alert_protocol { I2C_PROTOCOL_SMBUS_ALERT, + I2C_PROTOCOL_SMBUS_HOST_NOTIFY, }; /** @@ -184,6 +185,8 @@ 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 adcbef4bff61..009e27bb9abe 100644 --- a/include/uapi/linux/i2c.h +++ b/include/uapi/linux/i2c.h @@ -102,6 +102,7 @@ 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) |