[PATCH] i2c: slave framework support for SMBus Alert

[PATCH] i2c: slave framework support for SMBus Alert

[Brendan Higgins]

This adds support for an SMBus Alert to be requested from a slave mode Linux
I2C driver.

It appears that there is an attempt to keep master mode SMBus framework code
separate from raw I2C framework code, but that only appears to apply to master
mode I2C code. This seemed to make the most sense as part of i2c_algorithm.

This will not affect any existing drivers.

This has been tested with a slave mode driver I am currently working which I
can provide upon request (I am planning on submitting the driver as well, but
it part of a larger upstream submission).

My apologies in advance for any mistakes I might have made in the submission
process (I am new to the kernel mailing list).

Thanks!

[PATCH] i2c: slave framework support for SMBus Alert

[Brendan Higgins]

Currently, only handling SMBus alerts as a SMBus master is supported.
This adds support for the generation of SMBus Alerts as a slave.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
---
 drivers/i2c/i2c-core.c | 22 ++++++++++++++++++++++
 include/linux/i2c.h    |  5 +++++
 2 files changed, 27 insertions(+)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index e584d88..9d49cee 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -3252,6 +3252,28 @@ int i2c_slave_unregister(struct i2c_client *client)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(i2c_slave_unregister);
+
+int i2c_slave_smbus_alert(struct i2c_client *client)
+{
+	int ret;
+
+	if (!client->adapter->algo->smbus_alert_slave) {
+		dev_err(&client->dev, "%s: not supported by adapter\n",
+			__func__);
+		return -EOPNOTSUPP;
+	}
+
+	i2c_lock_adapter(client->adapter);
+	ret = client->adapter->algo->smbus_alert_slave(client);
+	i2c_unlock_adapter(client->adapter);
+
+	if (ret != 0)
+		dev_err(&client->dev, "%s: adapter returned error %d\n",
+			__func__, ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(i2c_slave_smbus_alert);
 #endif
 
 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 200cf13b..43b98f5 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -271,6 +271,8 @@ static inline int i2c_slave_event(struct i2c_client *client,
 {
 	return client->slave_cb(client, event, val);
 }
+
+extern int i2c_slave_smbus_alert(struct i2c_client *client);
 #endif
 
 /**
@@ -381,6 +383,8 @@ i2c_register_board_info(int busnum, struct i2c_board_info const *info,
  *   from the I2C_FUNC_* flags.
  * @reg_slave: Register given client to I2C slave mode of this adapter
  * @unreg_slave: Unregister given client from I2C slave mode of this adapter
+ * @smbus_alert_slave: Create an smbus alert from the I2C slave mode of this
+ *   adapter
  *
  * The following structs are for those who like to implement new bus drivers:
  * i2c_algorithm is the interface to a class of hardware solutions which can
@@ -410,6 +414,7 @@ struct i2c_algorithm {
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 	int (*reg_slave)(struct i2c_client *client);
 	int (*unreg_slave)(struct i2c_client *client);
+	int (*smbus_alert_slave)(struct i2c_client *client);
 #endif
 };
 
-- 
2.8.0.rc3.226.g39d4020

Re: [PATCH] i2c: slave framework support for SMBus Alert

[Wolfram Sang]

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> This has been tested with a slave mode driver I am currently working which I
> can provide upon request (I am planning on submitting the driver as well, but
> it part of a larger upstream submission).

Thanks for the patch.

When adding features to the core, I need a user for this feature
upstream. So, I noticed what you need, yet the patch needs to be resend
together with the i2c slave driver for a full review.

Regards,

   Wolfram


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