Hi Alain, some more comments for this one. I hope to come to a conclusion with Rob regarding the binding for patch 2, so we are then ready to go.
On Fri, Jul 03, 2020 at 01:36:07PM +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]> > --- > v2: identical to v1 > > drivers/i2c/i2c-core-smbus.c | 114 > +++++++++++++++++++++++++++++++++++++++++++ I came to the conclusion that this code should be in i2c-smbus.c. Because it is SMBus only. I agree that the current code layout is confusing. I will try to move the whole host-notify support to i2c-smbus in the next cycle. Yes, that means that one needs to select I2C_SMBUS in the config, too (unless you want to 'select' it with your driver). But most people won't need it so they can compile it away. This is what I2C_SMBUS is for. > include/linux/i2c-smbus.h | 12 +++++ > 2 files changed, 126 insertions(+) > > diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c > index f5c9787992e9..23ab9dc5ac85 100644 > --- a/drivers/i2c/i2c-core-smbus.c > +++ b/drivers/i2c/i2c-core-smbus.c > @@ -715,3 +715,117 @@ int of_i2c_setup_smbus_alert(struct i2c_adapter > *adapter) > } > EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert); > #endif > + > +#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; > + int ret; > + Can't we simplify 'index' handling similar to the testunit driver... > + switch (event) { > + case I2C_SLAVE_WRITE_REQUESTED: > + status->index = 0; ... by removing this line... > + break; > + 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: > + /* Handle host-notify if whole message received only */ > + if (status->index != SMBUS_HOST_NOTIFY_LEN) { > + status->index = U8_MAX; > + break; > + } > + > + ret = i2c_handle_smbus_host_notify(client->adapter, > + status->addr); > + if (ret < 0) > + return ret; > + status->index = U8_MAX; ... and handling the logic here like: + if (status->index == SMBUS_HOST_NOTIFY_LEN) + i2c_handle_smbus_host_notify(client->adapter, status->addr); + status->index = 0; Note that I2C_SLAVE_STOP doesn't return a retval, so we don't need to check i2c_handle_smbus_host_notify(). > + 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); > + status->index = U8_MAX; This line could go, too, if my simplification above works. > + > + 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) > +{ > + i2c_slave_unregister(client); > + kfree(client->dev.platform_data); > + i2c_unregister_device(client); > +} > +EXPORT_SYMBOL_GPL(i2c_free_slave_host_notify_device); Sidenote: With my recent series "i2c: slave: improve sanity checks when un-/registering" this code became NULL-safe (and IS_ERR safe, too). > +#endif > diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h > index 1e4e0de4ef8b..52e62f398f1c 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_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 NULL; return ERR_PTR(-ENOSYS); As the docs say, this function either returns a valid client or an ERR_PTR. > +} > +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 >
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