| Message ID | 20230105140307.272052-2-tomi.valkeinen@ideasonboard.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | i2c-atr and FPDLink | expand |
Hi Tomi, Thank you for the patch. On Thu, Jan 05, 2023 at 04:03:00PM +0200, Tomi Valkeinen wrote: > From: Luca Ceresoli <luca@lucaceresoli.net> > > An adapter might need to know when a new device is about to be > added. This will soon bee needed to implement an "I2C address > translator" (ATR for short), a device that propagates I2C transactions > with a different slave address (an "alias" address). An ATR driver > needs to know when a slave is being added to find a suitable alias and > program the device translation map. > > Add an attach/detach callback pair to allow adapter drivers to be > notified of clients being added and removed. I've asked in the review of v6 if we could instead use the BUS_NOTIFY_ADD_DEVICE and BUS_NOTIFY_DEL_DEVICE bus notifiers. There's been a follow up discussion with Andy, but no reply from you AFAICS. Have you given this a try ? It's not a mandatory requirement, but if it can't be done (or shouldn't be done), I'd like to know why. > Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net> > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> > --- > drivers/i2c/i2c-core-base.c | 21 ++++++++++++++++++++- > include/linux/i2c.h | 16 ++++++++++++++++ > 2 files changed, 36 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c > index 7539b0740351..8a0888ba89e5 100644 > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -916,6 +916,7 @@ int i2c_dev_irq_from_resources(const struct resource *resources, > struct i2c_client * > i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info) > { > + const struct i2c_attach_operations *attach_ops; > struct i2c_client *client; > int status; > > @@ -967,15 +968,24 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf > } > } > > + attach_ops = adap->attach_ops; > + > + if (attach_ops && attach_ops->attach_client && > + attach_ops->attach_client(adap, info, client)) > + goto out_remove_swnode; > + > status = device_register(&client->dev); > if (status) > - goto out_remove_swnode; > + goto out_detach_client; > > dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", > client->name, dev_name(&client->dev)); > > return client; > > +out_detach_client: > + if (attach_ops && attach_ops->detach_client) > + attach_ops->detach_client(adap, client); > out_remove_swnode: > device_remove_software_node(&client->dev); > out_err_put_of_node: > @@ -997,9 +1007,18 @@ EXPORT_SYMBOL_GPL(i2c_new_client_device); > */ > void i2c_unregister_device(struct i2c_client *client) > { > + const struct i2c_attach_operations *attach_ops; > + struct i2c_adapter *adap; > + > if (IS_ERR_OR_NULL(client)) > return; > > + adap = client->adapter; > + attach_ops = adap->attach_ops; > + > + if (attach_ops && attach_ops->detach_client) > + attach_ops->detach_client(adap, client); > + > if (client->dev.of_node) { > of_node_clear_flag(client->dev.of_node, OF_POPULATED); > of_node_put(client->dev.of_node); > diff --git a/include/linux/i2c.h b/include/linux/i2c.h > index f7c49bbdb8a1..9a385b6de388 100644 > --- a/include/linux/i2c.h > +++ b/include/linux/i2c.h > @@ -584,6 +584,21 @@ struct i2c_lock_operations { > void (*unlock_bus)(struct i2c_adapter *adapter, unsigned int flags); > }; > > +/** > + * struct i2c_attach_operations - callbacks to notify client attach/detach > + * @attach_client: Notify of new client being attached > + * @detach_client: Notify of new client being detached > + * > + * Both ops are optional. > + */ > +struct i2c_attach_operations { > + int (*attach_client)(struct i2c_adapter *adapter, > + const struct i2c_board_info *info, > + const struct i2c_client *client); > + void (*detach_client)(struct i2c_adapter *adapter, > + const struct i2c_client *client); > +}; > + > /** > * struct i2c_timings - I2C timing information > * @bus_freq_hz: the bus frequency in Hz > @@ -726,6 +741,7 @@ struct i2c_adapter { > > /* data fields that are valid for all devices */ > const struct i2c_lock_operations *lock_ops; > + const struct i2c_attach_operations *attach_ops; > struct rt_mutex bus_lock; > struct rt_mutex mux_lock; >
On 08/01/2023 05:13, Laurent Pinchart wrote: > Hi Tomi, > > Thank you for the patch. > > On Thu, Jan 05, 2023 at 04:03:00PM +0200, Tomi Valkeinen wrote: >> From: Luca Ceresoli <luca@lucaceresoli.net> >> >> An adapter might need to know when a new device is about to be >> added. This will soon bee needed to implement an "I2C address >> translator" (ATR for short), a device that propagates I2C transactions >> with a different slave address (an "alias" address). An ATR driver >> needs to know when a slave is being added to find a suitable alias and >> program the device translation map. >> >> Add an attach/detach callback pair to allow adapter drivers to be >> notified of clients being added and removed. > > I've asked in the review of v6 if we could instead use the > BUS_NOTIFY_ADD_DEVICE and BUS_NOTIFY_DEL_DEVICE bus notifiers. There's > been a follow up discussion with Andy, but no reply from you AFAICS. > Have you given this a try ? It's not a mandatory requirement, but if it > can't be done (or shouldn't be done), I'd like to know why. Sorry, I meant to mention this in the cover letter, but forgot: I haven't looked at the bus notifiers yet, but will have a look. I wanted to send a new revision due to the large amount of changes already done. Tomi
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 7539b0740351..8a0888ba89e5 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -916,6 +916,7 @@ int i2c_dev_irq_from_resources(const struct resource *resources, struct i2c_client * i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info) { + const struct i2c_attach_operations *attach_ops; struct i2c_client *client; int status; @@ -967,15 +968,24 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf } } + attach_ops = adap->attach_ops; + + if (attach_ops && attach_ops->attach_client && + attach_ops->attach_client(adap, info, client)) + goto out_remove_swnode; + status = device_register(&client->dev); if (status) - goto out_remove_swnode; + goto out_detach_client; dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", client->name, dev_name(&client->dev)); return client; +out_detach_client: + if (attach_ops && attach_ops->detach_client) + attach_ops->detach_client(adap, client); out_remove_swnode: device_remove_software_node(&client->dev); out_err_put_of_node: @@ -997,9 +1007,18 @@ EXPORT_SYMBOL_GPL(i2c_new_client_device); */ void i2c_unregister_device(struct i2c_client *client) { + const struct i2c_attach_operations *attach_ops; + struct i2c_adapter *adap; + if (IS_ERR_OR_NULL(client)) return; + adap = client->adapter; + attach_ops = adap->attach_ops; + + if (attach_ops && attach_ops->detach_client) + attach_ops->detach_client(adap, client); + if (client->dev.of_node) { of_node_clear_flag(client->dev.of_node, OF_POPULATED); of_node_put(client->dev.of_node); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index f7c49bbdb8a1..9a385b6de388 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -584,6 +584,21 @@ struct i2c_lock_operations { void (*unlock_bus)(struct i2c_adapter *adapter, unsigned int flags); }; +/** + * struct i2c_attach_operations - callbacks to notify client attach/detach + * @attach_client: Notify of new client being attached + * @detach_client: Notify of new client being detached + * + * Both ops are optional. + */ +struct i2c_attach_operations { + int (*attach_client)(struct i2c_adapter *adapter, + const struct i2c_board_info *info, + const struct i2c_client *client); + void (*detach_client)(struct i2c_adapter *adapter, + const struct i2c_client *client); +}; + /** * struct i2c_timings - I2C timing information * @bus_freq_hz: the bus frequency in Hz @@ -726,6 +741,7 @@ struct i2c_adapter { /* data fields that are valid for all devices */ const struct i2c_lock_operations *lock_ops; + const struct i2c_attach_operations *attach_ops; struct rt_mutex bus_lock; struct rt_mutex mux_lock;