[v3,1/2] i2c: smbus: add core function handling SMBus host-notify
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Message ID 1596431876-24115-2-git-send-email-alain.volmat@st.com
State In Next
Commit 2a71593da34d473461f2f5c3dbb53b883596188a
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Series
  • i2c: stm32: add host-notify support via i2c slave
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Commit Message

Alain Volmat Aug. 3, 2020, 5:17 a.m. UTC
SMBus Host-Notify protocol, from the adapter point of view
consist of receiving a message from a client, including the
client address and some other data.

It can be simply handled by creating a new slave device
and registering a callback performing the parsing of the
message received from the client.

This commit introduces two new core functions
  * i2c_new_slave_host_notify_device
  * i2c_free_slave_host_notify_device
that take care of registration of the new slave device and
callback and will call i2c_handle_smbus_host_notify once a
Host-Notify event is received.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
---
 v3: move smbus host-notify slave code into i2c-smbus.c file
     rework slave callback index handling
     add sanity check in slave free function
 v2: identical to v1
 drivers/i2c/i2c-smbus.c   | 107 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/i2c-smbus.h |  12 ++++++
 2 files changed, 119 insertions(+)

Comments

Pierre Yves MORDRET Aug. 4, 2020, 2:03 p.m. UTC | #1
Hi Alain

Look good for me

Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>

Best Regards

On 8/3/20 7:17 AM, Alain Volmat wrote:
> SMBus Host-Notify protocol, from the adapter point of view
> consist of receiving a message from a client, including the
> client address and some other data.
> 
> It can be simply handled by creating a new slave device
> and registering a callback performing the parsing of the
> message received from the client.
> 
> This commit introduces two new core functions
>   * i2c_new_slave_host_notify_device
>   * i2c_free_slave_host_notify_device
> that take care of registration of the new slave device and
> callback and will call i2c_handle_smbus_host_notify once a
> Host-Notify event is received.
> 
> Signed-off-by: Alain Volmat <alain.volmat@st.com>
> ---
>  v3: move smbus host-notify slave code into i2c-smbus.c file
>      rework slave callback index handling
>      add sanity check in slave free function
>  v2: identical to v1
>  drivers/i2c/i2c-smbus.c   | 107 ++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/i2c-smbus.h |  12 ++++++
>  2 files changed, 119 insertions(+)
> 
> diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
> index dc0108287ccf..d3d06e3b4f3b 100644
> --- a/drivers/i2c/i2c-smbus.c
> +++ b/drivers/i2c/i2c-smbus.c
> @@ -197,6 +197,113 @@ EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert);
>  
>  module_i2c_driver(smbalert_driver);
>  
> +#if IS_ENABLED(CONFIG_I2C_SLAVE)
> +#define SMBUS_HOST_NOTIFY_LEN	3
> +struct i2c_slave_host_notify_status {
> +	u8 index;
> +	u8 addr;
> +};
> +
> +static int i2c_slave_host_notify_cb(struct i2c_client *client,
> +				    enum i2c_slave_event event, u8 *val)
> +{
> +	struct i2c_slave_host_notify_status *status = client->dev.platform_data;
> +
> +	switch (event) {
> +	case I2C_SLAVE_WRITE_RECEIVED:
> +		/* We only retrieve the first byte received (addr)
> +		 * since there is currently no support to retrieve the data
> +		 * parameter from the client.
> +		 */
> +		if (status->index == 0)
> +			status->addr = *val;
> +		if (status->index < U8_MAX)
> +			status->index++;
> +		break;
> +	case I2C_SLAVE_STOP:
> +		if (status->index == SMBUS_HOST_NOTIFY_LEN)
> +			i2c_handle_smbus_host_notify(client->adapter,
> +						     status->addr);
> +		fallthrough;
> +	case I2C_SLAVE_WRITE_REQUESTED:
> +		status->index = 0;
> +		break;
> +	case I2C_SLAVE_READ_REQUESTED:
> +	case I2C_SLAVE_READ_PROCESSED:
> +		*val = 0xff;
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * i2c_new_slave_host_notify_device - get a client for SMBus host-notify support
> + * @adapter: the target adapter
> + * Context: can sleep
> + *
> + * Setup handling of the SMBus host-notify protocol on a given I2C bus segment.
> + *
> + * Handling is done by creating a device and its callback and handling data
> + * received via the SMBus host-notify address (0x8)
> + *
> + * This returns the client, which should be ultimately freed using
> + * i2c_free_slave_host_notify_device(); or an ERRPTR to indicate an error.
> + */
> +struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter)
> +{
> +	struct i2c_board_info host_notify_board_info = {
> +		I2C_BOARD_INFO("smbus_host_notify", 0x08),
> +		.flags  = I2C_CLIENT_SLAVE,
> +	};
> +	struct i2c_slave_host_notify_status *status;
> +	struct i2c_client *client;
> +	int ret;
> +
> +	status = kzalloc(sizeof(struct i2c_slave_host_notify_status),
> +			 GFP_KERNEL);
> +	if (!status)
> +		return ERR_PTR(-ENOMEM);
> +
> +	host_notify_board_info.platform_data = status;
> +
> +	client = i2c_new_client_device(adapter, &host_notify_board_info);
> +	if (IS_ERR(client)) {
> +		kfree(status);
> +		return client;
> +	}
> +
> +	ret = i2c_slave_register(client, i2c_slave_host_notify_cb);
> +	if (ret) {
> +		i2c_unregister_device(client);
> +		kfree(status);
> +		return ERR_PTR(ret);
> +	}
> +
> +	return client;
> +}
> +EXPORT_SYMBOL_GPL(i2c_new_slave_host_notify_device);
> +
> +/**
> + * i2c_free_slave_host_notify_device - free the client for SMBus host-notify
> + * support
> + * @client: the client to free
> + * Context: can sleep
> + *
> + * Free the i2c_client allocated via i2c_new_slave_host_notify_device
> + */
> +void i2c_free_slave_host_notify_device(struct i2c_client *client)
> +{
> +	if (IS_ERR_OR_NULL(client))
> +		return;
> +
> +	i2c_slave_unregister(client);
> +	kfree(client->dev.platform_data);
> +	i2c_unregister_device(client);
> +}
> +EXPORT_SYMBOL_GPL(i2c_free_slave_host_notify_device);
> +#endif
> +
>  /*
>   * SPD is not part of SMBus but we include it here for convenience as the
>   * target systems are the same.
> diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h
> index 1e4e0de4ef8b..1ef421818d3a 100644
> --- a/include/linux/i2c-smbus.h
> +++ b/include/linux/i2c-smbus.h
> @@ -38,6 +38,18 @@ static inline int of_i2c_setup_smbus_alert(struct i2c_adapter *adap)
>  	return 0;
>  }
>  #endif
> +#if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_I2C_SLAVE)
> +struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter);
> +void i2c_free_slave_host_notify_device(struct i2c_client *client);
> +#else
> +static inline struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter)
> +{
> +	return ERR_PTR(-ENOSYS);
> +}
> +static inline void i2c_free_slave_host_notify_device(struct i2c_client *client)
> +{
> +}
> +#endif
>  
>  #if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_DMI)
>  void i2c_register_spd(struct i2c_adapter *adap);
>
Wolfram Sang Sept. 9, 2020, 8:39 a.m. UTC | #2
On Mon, Aug 03, 2020 at 07:17:55AM +0200, Alain Volmat wrote:
> SMBus Host-Notify protocol, from the adapter point of view
> consist of receiving a message from a client, including the
> client address and some other data.
> 
> It can be simply handled by creating a new slave device
> and registering a callback performing the parsing of the
> message received from the client.
> 
> This commit introduces two new core functions
>   * i2c_new_slave_host_notify_device
>   * i2c_free_slave_host_notify_device
> that take care of registration of the new slave device and
> callback and will call i2c_handle_smbus_host_notify once a
> Host-Notify event is received.
> 
> Signed-off-by: Alain Volmat <alain.volmat@st.com>

Applied to for-next, thanks!

Patch
diff mbox series

diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
index dc0108287ccf..d3d06e3b4f3b 100644
--- a/drivers/i2c/i2c-smbus.c
+++ b/drivers/i2c/i2c-smbus.c
@@ -197,6 +197,113 @@  EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert);
 
 module_i2c_driver(smbalert_driver);
 
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+#define SMBUS_HOST_NOTIFY_LEN	3
+struct i2c_slave_host_notify_status {
+	u8 index;
+	u8 addr;
+};
+
+static int i2c_slave_host_notify_cb(struct i2c_client *client,
+				    enum i2c_slave_event event, u8 *val)
+{
+	struct i2c_slave_host_notify_status *status = client->dev.platform_data;
+
+	switch (event) {
+	case I2C_SLAVE_WRITE_RECEIVED:
+		/* We only retrieve the first byte received (addr)
+		 * since there is currently no support to retrieve the data
+		 * parameter from the client.
+		 */
+		if (status->index == 0)
+			status->addr = *val;
+		if (status->index < U8_MAX)
+			status->index++;
+		break;
+	case I2C_SLAVE_STOP:
+		if (status->index == SMBUS_HOST_NOTIFY_LEN)
+			i2c_handle_smbus_host_notify(client->adapter,
+						     status->addr);
+		fallthrough;
+	case I2C_SLAVE_WRITE_REQUESTED:
+		status->index = 0;
+		break;
+	case I2C_SLAVE_READ_REQUESTED:
+	case I2C_SLAVE_READ_PROCESSED:
+		*val = 0xff;
+		break;
+	}
+
+	return 0;
+}
+
+/**
+ * i2c_new_slave_host_notify_device - get a client for SMBus host-notify support
+ * @adapter: the target adapter
+ * Context: can sleep
+ *
+ * Setup handling of the SMBus host-notify protocol on a given I2C bus segment.
+ *
+ * Handling is done by creating a device and its callback and handling data
+ * received via the SMBus host-notify address (0x8)
+ *
+ * This returns the client, which should be ultimately freed using
+ * i2c_free_slave_host_notify_device(); or an ERRPTR to indicate an error.
+ */
+struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter)
+{
+	struct i2c_board_info host_notify_board_info = {
+		I2C_BOARD_INFO("smbus_host_notify", 0x08),
+		.flags  = I2C_CLIENT_SLAVE,
+	};
+	struct i2c_slave_host_notify_status *status;
+	struct i2c_client *client;
+	int ret;
+
+	status = kzalloc(sizeof(struct i2c_slave_host_notify_status),
+			 GFP_KERNEL);
+	if (!status)
+		return ERR_PTR(-ENOMEM);
+
+	host_notify_board_info.platform_data = status;
+
+	client = i2c_new_client_device(adapter, &host_notify_board_info);
+	if (IS_ERR(client)) {
+		kfree(status);
+		return client;
+	}
+
+	ret = i2c_slave_register(client, i2c_slave_host_notify_cb);
+	if (ret) {
+		i2c_unregister_device(client);
+		kfree(status);
+		return ERR_PTR(ret);
+	}
+
+	return client;
+}
+EXPORT_SYMBOL_GPL(i2c_new_slave_host_notify_device);
+
+/**
+ * i2c_free_slave_host_notify_device - free the client for SMBus host-notify
+ * support
+ * @client: the client to free
+ * Context: can sleep
+ *
+ * Free the i2c_client allocated via i2c_new_slave_host_notify_device
+ */
+void i2c_free_slave_host_notify_device(struct i2c_client *client)
+{
+	if (IS_ERR_OR_NULL(client))
+		return;
+
+	i2c_slave_unregister(client);
+	kfree(client->dev.platform_data);
+	i2c_unregister_device(client);
+}
+EXPORT_SYMBOL_GPL(i2c_free_slave_host_notify_device);
+#endif
+
 /*
  * SPD is not part of SMBus but we include it here for convenience as the
  * target systems are the same.
diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h
index 1e4e0de4ef8b..1ef421818d3a 100644
--- a/include/linux/i2c-smbus.h
+++ b/include/linux/i2c-smbus.h
@@ -38,6 +38,18 @@  static inline int of_i2c_setup_smbus_alert(struct i2c_adapter *adap)
 	return 0;
 }
 #endif
+#if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_I2C_SLAVE)
+struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter);
+void i2c_free_slave_host_notify_device(struct i2c_client *client);
+#else
+static inline struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter)
+{
+	return ERR_PTR(-ENOSYS);
+}
+static inline void i2c_free_slave_host_notify_device(struct i2c_client *client)
+{
+}
+#endif
 
 #if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_DMI)
 void i2c_register_spd(struct i2c_adapter *adap);