linux-kernel - [PATCH v2 2/4] i2c: addition of client hnotify reg/unreg callbacks

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Date:   Thu, 25 Jun 2020 09:39:27 +0200
From:   Alain Volmat <alain.volmat@...com>
To:     <wsa@...nel.org>, <robh+dt@...nel.org>
CC:     <mark.rutland@....com>, <pierre-yves.mordret@...com>,
        <mcoquelin.stm32@...il.com>, <alexandre.torgue@...com>,
        <linux-i2c@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <fabrice.gasnier@...com>,
        <alain.volmat@...com>
Subject: [PATCH v2 2/4] i2c: addition of client hnotify reg/unreg callbacks

Addition of two callbacks reg_hnotify_cli and unreg_hnotify_cli
that can be implemented by adapter drivers in order to take action
whenever a client with HOST_NOTIFY flag is being registered to it.

Signed-off-by: Alain Volmat <alain.volmat@...com>
---
v2: replace generic client reg/unreg callbacks with host-notify
    client reg/unreg callbacks

 drivers/i2c/i2c-core-base.c | 18 ++++++++++++++++--
 include/linux/i2c.h         |  8 ++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 26f03a14a478..46745e403e98 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -319,6 +319,14 @@ static int i2c_device_probe(struct device *dev)
 	if (!client)
 		return 0;
 
+	if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
+		if (client->adapter->algo->reg_hnotify_cli) {
+			status = client->adapter->algo->reg_hnotify_cli(client);
+			if (status)
+				return status;
+		}
+	}
+
 	driver = to_i2c_driver(dev->driver);
 
 	client->irq = client->init_irq;
@@ -415,8 +423,11 @@ static int i2c_device_probe(struct device *dev)
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
 put_sync_adapter:
-	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
+	if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 		pm_runtime_put_sync(&client->adapter->dev);
+		if (client->adapter->algo->unreg_hnotify_cli)
+			client->adapter->algo->unreg_hnotify_cli(client);
+	}
 
 	return status;
 }
@@ -442,8 +453,11 @@ static int i2c_device_remove(struct device *dev)
 	device_init_wakeup(&client->dev, false);
 
 	client->irq = 0;
-	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
+	if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 		pm_runtime_put(&client->adapter->dev);
+		if (client->adapter->algo->unreg_hnotify_cli)
+			client->adapter->algo->unreg_hnotify_cli(client);
+	}
 
 	return status;
 }
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index b8b8963f8bb9..35ad108adc68 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -507,6 +507,10 @@ i2c_register_board_info(int busnum, struct i2c_board_info const *info,
  *   so e.g. PMICs can be accessed very late before shutdown. Optional.
  * @functionality: Return the flags that this algorithm/adapter pair supports
  *   from the ``I2C_FUNC_*`` flags.
+ * @reg_hnotify_cli: Callback informing that a new client with HOST_NOTIFY flag
+ *   is being registered
+ * @unreg_hnotify_cli: Callback informing that a client with HOST_NOTIFY flag
+ *   is being removed
  * @reg_slave: Register given client to I2C slave mode of this adapter
  * @unreg_slave: Unregister given client from I2C slave mode of this adapter
  *
@@ -543,6 +547,10 @@ struct i2c_algorithm {
 	/* To determine what the adapter supports */
 	u32 (*functionality)(struct i2c_adapter *adap);
 
+	/* To inform the adapter of the probe/remove of a HOST_NOTIFY client */
+	int (*reg_hnotify_cli)(struct i2c_client *client);
+	void (*unreg_hnotify_cli)(struct i2c_client *client);
+
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 	int (*reg_slave)(struct i2c_client *client);
 	int (*unreg_slave)(struct i2c_client *client);
-- 
2.7.4