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Diffstat (limited to 'drivers/i2c/i2c-smbus.c')
-rw-r--r--drivers/i2c/i2c-smbus.c64
1 files changed, 57 insertions, 7 deletions
diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
index 97f338b123..25bc7b8d98 100644
--- a/drivers/i2c/i2c-smbus.c
+++ b/drivers/i2c/i2c-smbus.c
@@ -34,6 +34,7 @@ static int smbus_do_alert(struct device *dev, void *addrp)
struct i2c_client *client = i2c_verify_client(dev);
struct alert_data *data = addrp;
struct i2c_driver *driver;
+ int ret;
if (!client || client->addr != data->addr)
return 0;
@@ -47,16 +48,47 @@ static int smbus_do_alert(struct device *dev, void *addrp)
device_lock(dev);
if (client->dev.driver) {
driver = to_i2c_driver(client->dev.driver);
- if (driver->alert)
+ if (driver->alert) {
+ /* Stop iterating after we find the device */
driver->alert(client, data->type, data->data);
- else
+ ret = -EBUSY;
+ } else {
dev_warn(&client->dev, "no driver alert()!\n");
- } else
+ ret = -EOPNOTSUPP;
+ }
+ } else {
dev_dbg(&client->dev, "alert with no driver\n");
+ ret = -ENODEV;
+ }
+ device_unlock(dev);
+
+ return ret;
+}
+
+/* Same as above, but call back all drivers with alert handler */
+
+static int smbus_do_alert_force(struct device *dev, void *addrp)
+{
+ struct i2c_client *client = i2c_verify_client(dev);
+ struct alert_data *data = addrp;
+ struct i2c_driver *driver;
+
+ if (!client || (client->flags & I2C_CLIENT_TEN))
+ return 0;
+
+ /*
+ * Drivers should either disable alerts, or provide at least
+ * a minimal handler. Lock so the driver won't change.
+ */
+ device_lock(dev);
+ if (client->dev.driver) {
+ driver = to_i2c_driver(client->dev.driver);
+ if (driver->alert)
+ driver->alert(client, data->type, data->data);
+ }
device_unlock(dev);
- /* Stop iterating after we find the device */
- return -EBUSY;
+ return 0;
}
/*
@@ -67,6 +99,7 @@ static irqreturn_t smbus_alert(int irq, void *d)
{
struct i2c_smbus_alert *alert = d;
struct i2c_client *ara;
+ unsigned short prev_addr = I2C_CLIENT_END; /* Not a valid address */
ara = alert->ara;
@@ -94,8 +127,25 @@ static irqreturn_t smbus_alert(int irq, void *d)
data.addr, data.data);
/* Notify driver for the device which issued the alert */
- device_for_each_child(&ara->adapter->dev, &data,
- smbus_do_alert);
+ status = device_for_each_child(&ara->adapter->dev, &data,
+ smbus_do_alert);
+ /*
+ * If we read the same address more than once, and the alert
+ * was not handled by a driver, it won't do any good to repeat
+ * the loop because it will never terminate. Try again, this
+ * time calling the alert handlers of all devices connected to
+ * the bus, and abort the loop afterwards. If this helps, we
+ * are all set. If it doesn't, there is nothing else we can do,
+ * so we might as well abort the loop.
+ * Note: This assumes that a driver with alert handler handles
+ * the alert properly and clears it if necessary.
+ */
+ if (data.addr == prev_addr && status != -EBUSY) {
+ device_for_each_child(&ara->adapter->dev, &data,
+ smbus_do_alert_force);
+ break;
+ }
+ prev_addr = data.addr;
}
return IRQ_HANDLED;