| Message ID | 20130916135118.GD29403@sirena.org.uk |
|---|---|
| State | RFC |
| Headers | show |
On Mon, Sep 16, 2013 at 02:51:18PM +0100, Mark Brown wrote: > On Mon, Sep 16, 2013 at 02:44:35PM +0200, Linus Walleij wrote: > > > I've tried to fix this for DT-only I2C devices > > and this very driver was the reason. > > > But a tiresome regression due to drivers relying on this > > i2c_device_id not being NULL and inability to remove it from the I2C > > core without refactoring the world ensued, see: > > commit c80f52847c50109ca248c22efbf71ff10553dca4 > > Oh, that was the change... > > > Reverted in: > > commit 661f6c1cd926c6c973e03c6b5151d161f3a666ed > > > For this reason I think: > > http://marc.info/?l=linux-next&m=137148411231784&w=2 > > > I have tentatively given up getting pure DT I2C drivers > > to probe, I don't think I have the whole picture, but > > Wolfram has serious doubts about this and say we have > > to be careful .... > > > Wolfram, do you have some ideas on how we should > > proceed or ar you happy with merging this as-is? > > I'd have expected that it should be possible to change things such that > the change in the core doesn't produce any change in behaviour for > existing drivers. Can we not change the patch so that i2c_match_id() > copes with getting a NULL id_table? Something like this: I hacked something like this after Linus posted his approach. However, I found out that run time instanciating ('new_device' file) needs an id_table. I wasn't to keen on disabling the feature for dt-only drivers. That's where I stopped, due to lack of time.
On Mon, 16 Sep 2013, Wolfram Sang wrote: > > On Mon, Sep 16, 2013 at 02:51:18PM +0100, Mark Brown wrote: > > On Mon, Sep 16, 2013 at 02:44:35PM +0200, Linus Walleij wrote: > > > > > I've tried to fix this for DT-only I2C devices > > > and this very driver was the reason. > > > > > But a tiresome regression due to drivers relying on this > > > i2c_device_id not being NULL and inability to remove it from the I2C > > > core without refactoring the world ensued, see: > > > commit c80f52847c50109ca248c22efbf71ff10553dca4 > > > > Oh, that was the change... > > > > > Reverted in: > > > commit 661f6c1cd926c6c973e03c6b5151d161f3a666ed > > > > > For this reason I think: > > > http://marc.info/?l=linux-next&m=137148411231784&w=2 > > > > > I have tentatively given up getting pure DT I2C drivers > > > to probe, I don't think I have the whole picture, but > > > Wolfram has serious doubts about this and say we have > > > to be careful .... > > > > > Wolfram, do you have some ideas on how we should > > > proceed or ar you happy with merging this as-is? > > > > I'd have expected that it should be possible to change things such that > > the change in the core doesn't produce any change in behaviour for > > existing drivers. Can we not change the patch so that i2c_match_id() > > copes with getting a NULL id_table? Something like this: > > I hacked something like this after Linus posted his approach. However, I > found out that run time instanciating ('new_device' file) needs an > id_table. I wasn't to keen on disabling the feature for dt-only drivers. > That's where I stopped, due to lack of time. So in the mean time are you happy with this "dummy" approach?
> So in the mean time are you happy with this "dummy" approach?
No. "dummy" is reserved for a dummy device in case an i2c slave needs
more than one address. The proper solution would be if
i2c_sysfs_new_device() could recognize the of_device_ids.
> > So in the mean time are you happy with this "dummy" approach? > > No. "dummy" is reserved for a dummy device in case an i2c slave needs > more than one address. The proper solution would be if > i2c_sysfs_new_device() could recognize the of_device_ids. Okay, thanks for clarifying.
On Mon, Sep 16, 2013 at 05:05:37PM +0100, Lee Jones wrote: > > > So in the mean time are you happy with this "dummy" approach? > > No. "dummy" is reserved for a dummy device in case an i2c slave needs > > more than one address. The proper solution would be if > > i2c_sysfs_new_device() could recognize the of_device_ids. > Okay, thanks for clarifying. Or for now to use something like stw481x (even if it's never expected to actually make a difference).
On Mon, 16 Sep 2013, Mark Brown wrote: > On Mon, Sep 16, 2013 at 05:05:37PM +0100, Lee Jones wrote: > > > > So in the mean time are you happy with this "dummy" approach? > > > > No. "dummy" is reserved for a dummy device in case an i2c slave needs > > > more than one address. The proper solution would be if > > > i2c_sysfs_new_device() could recognize the of_device_ids. > > > Okay, thanks for clarifying. > > Or for now to use something like stw481x (even if it's never expected to > actually make a difference). If Linus wants to resubmit, I'm happy with that.
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 29d3f04..61087ea 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -67,6 +67,9 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id, const struct i2c_client *client) { + if (!id) + return NULL; + while (id->name[0]) { if (strcmp(client->name, id->name) == 0) return id; @@ -92,11 +95,8 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv) return 1; driver = to_i2c_driver(drv); - /* match on an id table if there is one */ - if (driver->id_table) - return i2c_match_id(driver->id_table, client) != NULL; - return 0; + return i2c_match_id(driver->id_table, client) != NULL; } @@ -246,7 +246,7 @@ static int i2c_device_probe(struct device *dev) return 0; driver = to_i2c_driver(dev->driver); - if (!driver->probe || !driver->id_table) + if (!driver->probe) return -ENODEV; client->driver = driver; if (!device_can_wakeup(&client->dev))