Hi Dmitry Torokhov, Thanks for the feedback. > Subject: Re: [PATCH v2 1/2] Input: exc3000 - Simplify probe() > > On Wed, Jul 19, 2023 at 06:43:47AM +0000, Biju Das wrote: > > Hi Dmitry Torokhov, > > > > Thanks for the feedback. > > > > > Subject: Re: [PATCH v2 1/2] Input: exc3000 - Simplify probe() > > > > > > On Mon, Jul 17, 2023 at 06:45:27PM +0000, Biju Das wrote: > > > > Hi Dmitry, > > > > > > > > > Subject: Re: [PATCH v2 1/2] Input: exc3000 - Simplify probe() > > > > > > > > > > On Mon, Jul 17, 2023 at 07:15:50PM +0100, Mark Brown wrote: > > > > > > On Mon, Jul 17, 2023 at 04:35:02PM +0000, Biju Das wrote: > > > > > > > > > > > > > The .device_get_match_data callbacks are missing for I2C and > > > > > > > SPI bus > > > > > subsystems. > > > > > > > Can you please throw some lights on this? > > > > > > > > > > > > It's the first time I've ever heard of that callback, I don't > > > > > > know why whoever added it wouldn't have done those buses in > > > > > > particular or if it just didn't happen. Try adding it and if > > > > > > it works send > > > the patches? > > > > > > > > > > I think there is a disconnect. Right now device_get_match_data > > > > > callbacks are part of fwnode_operations. I was proposing to add > > > > > another optional device_get_match_data callback to 'struct > bus_type' > > > > > to allow individual buses control how match data is handled, > > > > > before (or after) jumping into the fwnode-backed > > > > > device_get_match_data > > > callbacks. > > > > > > > > That is what implemented here [1] and [2] right? > > > > > > > > > > > > First it check for fwnode-backed device_get_match_data callbacks > > > > and Fallback is bus-type based match. > > > > > > > > Looks like you are proposing to unify [1] and [2] and you want the > > > > logic to be other way around. ie, first bus-type match, then > > > > fwnode-backed callbacks? > > > > > > > > > > I do not have a strong preference for the ordering, i.e. I think it > > > is perfectly fine to do the generic fwnode-based lookup and if there > > > is no match have bus method called as a fallback, > > > > That involves a bit of work. > > > > const void *device_get_match_data(const struct device *dev); > > > > const struct i2c_device_id *i2c_match_id(const struct i2c_device_id > *id, > > const struct i2c_client *client); > > > > const struct spi_device_id *spi_get_device_id(const struct spi_device > > *sdev); > > > > Basically, the bus-client driver(such as exc3000) needs to pass struct > > device and device_get_match_data after generic fwnode-based lookup, > > needs to find the bus type based on struct device and call a new > > generic > > void* bus_get_match_data(void*) callback, so that each bus interface > > can do a match. > > Yes, something like this (which does not seem that involved to me...): Looks it will work. But there is some 2 additional checks in core code, every driver which is not bus type need to go through this checks. Also in Bus specific callback, there are 2 additional checks. So, performance wise [1] is better. Moreover, we need to avoid code duplication with [1] [1] https://elixir.bootlin.com/linux/v6.5-rc2/source/drivers/i2c/i2c-core-base.c#L125 What core people thinking about Dmitry's proposal? Cheers, Biju > > diff --git a/drivers/base/property.c b/drivers/base/property.c index > 8c40abed7852..cc0bf7bb6f3a 100644 > --- a/drivers/base/property.c > +++ b/drivers/base/property.c > @@ -1277,7 +1277,13 @@ EXPORT_SYMBOL(fwnode_graph_parse_endpoint); > > const void *device_get_match_data(const struct device *dev) { > - return fwnode_call_ptr_op(dev_fwnode(dev), device_get_match_data, > dev); > + const void *data; > + > + data = fwnode_call_ptr_op(dev_fwnode(dev), device_get_match_data, > dev); > + if (!data && dev->bus && dev->bus->get_match_data) > + data = dev->bus->get_match_data(dev); > + > + return data; > } > EXPORT_SYMBOL_GPL(device_get_match_data); > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c > index 60746652fd52..5fe47bc491a6 100644 > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -114,6 +114,26 @@ const struct i2c_device_id *i2c_match_id(const > struct i2c_device_id *id, } EXPORT_SYMBOL_GPL(i2c_match_id); > > +static const void *i2c_device_get_match_data(const struct device *dev) > +{ > + const struct i2c_client *client = to_i2c_client(dev); > + const struct i2c_driver *driver; > + const struct i2c_device_id *match; > + > + if (!dev->driver) > + return NULL; > + > + driver = to_i2c_driver(dev->driver); > + if (!driver) > + return NULL; > + > + match = i2c_match_id(driver->id_table, client); > + if (!match) > + return NULL; > + > + return (const void *)match->driver_data; } > + > const void *i2c_get_match_data(const struct i2c_client *client) { > struct i2c_driver *driver = to_i2c_driver(client->dev.driver); > @@ -695,6 +715,7 @@ struct bus_type i2c_bus_type = { > .probe = i2c_device_probe, > .remove = i2c_device_remove, > .shutdown = i2c_device_shutdown, > + .get_match_data = i2c_device_get_match_data, > }; > EXPORT_SYMBOL_GPL(i2c_bus_type); > > diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h > index ae10c4322754..3f2cba28a1af 100644 > --- a/include/linux/device/bus.h > +++ b/include/linux/device/bus.h > @@ -102,6 +102,8 @@ struct bus_type { > int (*dma_configure)(struct device *dev); > void (*dma_cleanup)(struct device *dev); > > + const void *(*get_match_data)(const struct device *dev); > + > const struct dev_pm_ops *pm; > > const struct iommu_ops *iommu_ops; > > > Thanks. > > -- > Dmitry
