| Message ID | 1588657871-14747-2-git-send-email-alain.volmat@st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | stm32-f7: Addition of SMBus Alert / Host-notify features | expand |
Hi all, Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com> Thanks On 5/5/20 7:51 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_smbus_host_notify_device > * i2c_free_smbus_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> > --- > drivers/i2c/i2c-core-smbus.c | 105 +++++++++++++++++++++++++++++++++++ > include/linux/i2c-smbus.h | 2 + > 2 files changed, 107 insertions(+) > > diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c > index b34d2ff06931..0c7e135c73e1 100644 > --- a/drivers/i2c/i2c-core-smbus.c > +++ b/drivers/i2c/i2c-core-smbus.c > @@ -708,3 +708,108 @@ int of_i2c_setup_smbus_alert(struct i2c_adapter *adapter) > } > EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert); > #endif > + > +struct i2c_smbus_host_notify_status { > + bool notify_start; > + u8 addr; > +}; > + > +static int i2c_smbus_host_notify_cb(struct i2c_client *client, > + enum i2c_slave_event event, u8 *val) > +{ > + struct i2c_smbus_host_notify_status *status = client->dev.platform_data; > + int ret; > + > + switch (event) { > + case I2C_SLAVE_WRITE_REQUESTED: > + status->notify_start = true; > + break; > + case I2C_SLAVE_WRITE_RECEIVED: > + /* We only retrieve the first byte received (addr) > + * since there is currently no way to retrieve the data > + * parameter from the client. > + */ > + if (!status->notify_start) > + break; > + status->addr = *val; > + status->notify_start = false; > + break; > + case I2C_SLAVE_STOP: > + ret = i2c_handle_smbus_host_notify(client->adapter, > + status->addr); > + if (ret < 0) { > + dev_warn(&client->adapter->dev, "failed to handle host_notify (%d)\n", > + ret); > + return ret; > + } > + break; > + default: > + /* Only handle necessary events */ > + break; > + } > + > + return 0; > +} > + > +/** > + * i2c_new_smbus_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_smbus_host_notify_device(); or an ERRPTR to indicate an error. > + */ > +struct i2c_client *i2c_new_smbus_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_smbus_host_notify_status *status; > + struct i2c_client *client; > + int ret; > + > + status = kzalloc(sizeof(struct i2c_smbus_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_smbus_host_notify_cb); > + if (ret) { > + i2c_unregister_device(client); > + kfree(status); > + return ERR_PTR(ret); > + } > + > + return client; > +} > +EXPORT_SYMBOL_GPL(i2c_new_smbus_host_notify_device); > + > +/** > + * i2c_free_smbus_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_smbus_host_notify_device > + */ > +void i2c_free_smbus_host_notify_device(struct i2c_client *client) > +{ > + i2c_slave_unregister(client); > + kfree(client->dev.platform_data); > + i2c_unregister_device(client); > +} > +EXPORT_SYMBOL_GPL(i2c_free_smbus_host_notify_device); > diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h > index 8c5459034f92..926f6d8ae30d 100644 > --- a/include/linux/i2c-smbus.h > +++ b/include/linux/i2c-smbus.h > @@ -38,5 +38,7 @@ static inline int of_i2c_setup_smbus_alert(struct i2c_adapter *adap) > return 0; > } > #endif > +struct i2c_client *i2c_new_smbus_host_notify_device(struct i2c_adapter *adapter); > +void i2c_free_smbus_host_notify_device(struct i2c_client *client); > > #endif /* _LINUX_I2C_SMBUS_H */ >
Adding Benjamin who mainly implemented this. On Tue, May 05, 2020 at 07:51:08AM +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_smbus_host_notify_device > * i2c_free_smbus_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. Yay, cool idea to use the slave interface. I like it a lot! > +static int i2c_smbus_host_notify_cb(struct i2c_client *client, > + enum i2c_slave_event event, u8 *val) > +{ > + struct i2c_smbus_host_notify_status *status = client->dev.platform_data; > + int ret; > + > + switch (event) { > + case I2C_SLAVE_WRITE_REQUESTED: > + status->notify_start = true; > + break; > + case I2C_SLAVE_WRITE_RECEIVED: > + /* We only retrieve the first byte received (addr) > + * since there is currently no way to retrieve the data > + * parameter from the client. Maybe s/no way/no support/ ? I still wonder if we couldn't add it somehow. Once we find a device which needs this, of course. > + */ > + if (!status->notify_start) > + break; > + status->addr = *val; > + status->notify_start = false; > + break; > + case I2C_SLAVE_STOP: What about setting 'notify_start' to false here as well? In the case of an incomplete write? > + ret = i2c_handle_smbus_host_notify(client->adapter, > + status->addr); > + if (ret < 0) { > + dev_warn(&client->adapter->dev, "failed to handle host_notify (%d)\n", > + ret); I think we should rather add such error strings to the core if we think they are needed. I am not convinced they are, though. > + return ret; > + } > + break; > + default: > + /* Only handle necessary events */ > + break; > + } > + > + return 0; > +} > + Rest of the code looks good. Maybe we should compile all this only when I2C_SLAVE is enabled?
On Sat, May 23, 2020 at 10:46:25AM +0000, Wolfram Sang wrote: > > Adding Benjamin who mainly implemented this. > > On Tue, May 05, 2020 at 07:51:08AM +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_smbus_host_notify_device > > * i2c_free_smbus_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. > > Yay, cool idea to use the slave interface. I like it a lot! > > > +static int i2c_smbus_host_notify_cb(struct i2c_client *client, > > + enum i2c_slave_event event, u8 *val) > > +{ > > + struct i2c_smbus_host_notify_status *status = client->dev.platform_data; > > + int ret; > > + > > + switch (event) { > > + case I2C_SLAVE_WRITE_REQUESTED: > > + status->notify_start = true; > > + break; > > + case I2C_SLAVE_WRITE_RECEIVED: > > + /* We only retrieve the first byte received (addr) > > + * since there is currently no way to retrieve the data > > + * parameter from the client. > > Maybe s/no way/no support/ ? I still wonder if we couldn't add it > somehow. Once we find a device which needs this, of course. Indeed. Such support can be added later on once such device is found. For the time being I will state "no support" > > > + */ > > + if (!status->notify_start) > > + break; > > + status->addr = *val; > > + status->notify_start = false; > > + break; > > + case I2C_SLAVE_STOP: > > What about setting 'notify_start' to false here as well? In the case of > an incomplete write? Ok. I will check that notify_start is false before calling host_notify (since otherwise it will call i2c_handle_smbus_host_notify with a bad addr value) and reset notify_start to false if it is still true. > > > + ret = i2c_handle_smbus_host_notify(client->adapter, > > + status->addr); > > + if (ret < 0) { > > + dev_warn(&client->adapter->dev, "failed to handle host_notify (%d)\n", > > + ret); > > I think we should rather add such error strings to the core if we think > they are needed. I am not convinced they are, though. Agreed, this error can be removed. > > > + return ret; > > + } > > + break; > > + default: > > + /* Only handle necessary events */ > > + break; > > + } > > + > > + return 0; > > +} > > + > > Rest of the code looks good. Maybe we should compile all this only when > I2C_SLAVE is enabled? > Yes, I will enclose that around I2C_SLAVE support check.
diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c index b34d2ff06931..0c7e135c73e1 100644 --- a/drivers/i2c/i2c-core-smbus.c +++ b/drivers/i2c/i2c-core-smbus.c @@ -708,3 +708,108 @@ int of_i2c_setup_smbus_alert(struct i2c_adapter *adapter) } EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert); #endif + +struct i2c_smbus_host_notify_status { + bool notify_start; + u8 addr; +}; + +static int i2c_smbus_host_notify_cb(struct i2c_client *client, + enum i2c_slave_event event, u8 *val) +{ + struct i2c_smbus_host_notify_status *status = client->dev.platform_data; + int ret; + + switch (event) { + case I2C_SLAVE_WRITE_REQUESTED: + status->notify_start = true; + break; + case I2C_SLAVE_WRITE_RECEIVED: + /* We only retrieve the first byte received (addr) + * since there is currently no way to retrieve the data + * parameter from the client. + */ + if (!status->notify_start) + break; + status->addr = *val; + status->notify_start = false; + break; + case I2C_SLAVE_STOP: + ret = i2c_handle_smbus_host_notify(client->adapter, + status->addr); + if (ret < 0) { + dev_warn(&client->adapter->dev, "failed to handle host_notify (%d)\n", + ret); + return ret; + } + break; + default: + /* Only handle necessary events */ + break; + } + + return 0; +} + +/** + * i2c_new_smbus_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_smbus_host_notify_device(); or an ERRPTR to indicate an error. + */ +struct i2c_client *i2c_new_smbus_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_smbus_host_notify_status *status; + struct i2c_client *client; + int ret; + + status = kzalloc(sizeof(struct i2c_smbus_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_smbus_host_notify_cb); + if (ret) { + i2c_unregister_device(client); + kfree(status); + return ERR_PTR(ret); + } + + return client; +} +EXPORT_SYMBOL_GPL(i2c_new_smbus_host_notify_device); + +/** + * i2c_free_smbus_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_smbus_host_notify_device + */ +void i2c_free_smbus_host_notify_device(struct i2c_client *client) +{ + i2c_slave_unregister(client); + kfree(client->dev.platform_data); + i2c_unregister_device(client); +} +EXPORT_SYMBOL_GPL(i2c_free_smbus_host_notify_device); diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h index 8c5459034f92..926f6d8ae30d 100644 --- a/include/linux/i2c-smbus.h +++ b/include/linux/i2c-smbus.h @@ -38,5 +38,7 @@ static inline int of_i2c_setup_smbus_alert(struct i2c_adapter *adap) return 0; } #endif +struct i2c_client *i2c_new_smbus_host_notify_device(struct i2c_adapter *adapter); +void i2c_free_smbus_host_notify_device(struct i2c_client *client); #endif /* _LINUX_I2C_SMBUS_H */
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_smbus_host_notify_device * i2c_free_smbus_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> --- drivers/i2c/i2c-core-smbus.c | 105 +++++++++++++++++++++++++++++++++++ include/linux/i2c-smbus.h | 2 + 2 files changed, 107 insertions(+)