diff --git a/Documentation/i2c/smbus-protocol b/Documentation/i2c/smbus-protocol
index 6012b12b35109f686da47253b947fba050a34f44..14d4ec1be2457db04d0f76fe87b3ff323ece9e8a 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 3b6765a4ebe9a5a03ecc6bd3847bb1d575262bb4..f574995b41c14737c5afcd39215ca91e783958ca 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 8f1b086ca5bcc962cbd9d509c4235346c46fefbc..4ac95bbe53ef6add355d457c62bd630cf84093fd 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 37a45dcd65928cdd612a2587c8c23145552d52cc..fffdc270ca18518f4e3c05b5efd2749f52b28f50 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 adcbef4bff610af948ab40cfd3d63b6d167abaa8..009e27bb9abe199b3ee2bc7bcced083cba25c653 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)