Messages in this thread | | | Date | Thu, 19 Jan 2023 12:35:20 +0100 | From | Luca Ceresoli <> | Subject | Re: [PATCH v7 1/7] i2c: add I2C Address Translator (ATR) support |
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Hi Tomi, Andy,
On Thu, 19 Jan 2023 12:09:57 +0200 Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> wrote:
> On 19/01/2023 10:21, Luca Ceresoli wrote: > > <snip> > > >>>>> +void i2c_atr_set_driver_data(struct i2c_atr *atr, void *data) > >>>>> +{ > >>>>> + atr->priv = data; > >>>>> +} > >>>>> +EXPORT_SYMBOL_NS_GPL(i2c_atr_set_driver_data, I2C_ATR); > >>>>> + > >>>>> +void *i2c_atr_get_driver_data(struct i2c_atr *atr) > >>>>> +{ > >>>>> + return atr->priv; > >>>>> +} > >>>>> +EXPORT_SYMBOL_NS_GPL(i2c_atr_get_driver_data, I2C_ATR); > >>>> > >>>> Just to be sure: Is it really _driver_ data and not _device instance_ data? > >>> > >>> It is device instance data indeed. I don't remember why this got > >>> changed, but in v3 it was i2c_atr_set_clientdata(). > >> > >> It's me who was and is against calling it clientdata due to possible > >> confusion with i2c_set/get_clientdata() that is about *driver data*. > >> I missed that time the fact that this is about device instance data. > >> I dunno which name would be better in this case, i2c_atr_set/get_client_priv() ? > > > > Not sure I'm following you here. The i2c_atr_set_clientdata() name was > > given for similarity with i2c_set_clientdata(). The latter wraps > > dev_set_drvdata(), which sets `struct device`->driver_data. There is > > one driver_data per each `struct device` instance, not per each driver. > > The same goes for i2c_atr_set_driver_data(): there is one priv pointer > > per each `struct i2c_atr` instance. > > I'm a bit confused. What is "driver data" and what is "device instance > data"? > > This deals with the driver's private data, where the "driver" is the > owner/creator of the i2c-atr. The i2c-atr itself doesn't have a device > (it's kind of part of the owner's device), and there's no driver in > i2c-atr.c > > I don't like "client" here, as it reminds me of i2c_client (especially > as we're in i2c context). > > What about i2c_atr_set_user_data()? Or "owner_data"?
Ah, only now I got the point Andy made initially about "client" not being an appropriate word.
In i2c we have:
i2c_set_clientdata(struct i2c_client *client, void *data) ^^^^^^~~~~ ^^^^^^ ~~~~
so "client" clearly makes sense there, now here.
The same logic applied here would lead to:
i2c_atr_set_atrdata(struct i2c_atr *atr, void *data) ^^^~~~~ ^^^ ~~~~
which makes sense but it is a ugly IMO.
So I think i2c_atr_get_driver_data() in this v7 makes sense, it's to set the data that the ATR driver instance needs.
This is coherent with logic in spi/spi.h:
spi_set_drvdata(struct spi_device *spi, void *data)
except for the abbreviation ("_drvdata" vs "_driver_data").
Andy, Tomi, would i2c_atr_set_drvdata() be OK for you, just like SPI does?
-- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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