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 <[email protected]>
---
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);
--
2.7.4
Hi Alain
Look good for me
Reviewed-by: Pierre-Yves MORDRET <[email protected]>
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 <[email protected]>
> ---
> 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);
>
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 <[email protected]>
Applied to for-next, thanks!