Hi Antti, The driver's .probe() after i2c_new_device() is simply not supposed to fail. You should only use i2c_new_device() if you are 100% sure that there is a device of the given type at the given address. Checking i2c_get_clientdata() is an ugly trick that you should no longer need to use. i2c_driver.detect() is used for fully auto-detectable, standalone devices. Mostly hardware monitoring chips fall into this category. You should never use that mechanism for video chips, and as a matter of fact, I2C_CLASS_* flags for analog and digital TV were killed years ago. To make it clearer: for everything TV/video related, only .probe() and .remove() are relevant, .detect() is not. I think you simply want to use i2c_new_probed_device() instead of i2c_new_device(), so that the i2c client is only instantiated if the right device is present at the address. In the case where different chips could be present and you have to differentiate between then, you can provide a custom detection callback to i2c_new_probed_device(), and have it return -ENODEV if the right device isn't found. If you don't provide a custom detection callback, the default one is used (i2c_probe_func_quick_read in i2c-core.c), that only checks for any device's presence at a specified address. Hope that clarifies, Jean On Tue, 15 Oct 2013 18:13:39 +0300, Antti Palosaari wrote: > Jean > could you look that and comment how I should implement it properly. > I saw you also added i2c_new_probed_device() [1] that these TV drivers > could be ported properly I2C model. > > [1] http://lists.lm-sensors.org/pipermail/i2c/2007-March/000990.html > > I am pretty sure I have looked and tested all the I2C pieces quite > carefully. There is .detect() callback which looks just what I need, but > unfortunately it is nor called in case of i2c_new_probed_device() and > i2c_new_device(). > > > > On 14.10.2013 05:31, Antti Palosaari wrote: > > On 14.10.2013 03:10, Antti Palosaari wrote: > >> kernel: usb 1-2: rtl2832u_tuner_attach: > >> kernel: e4000 5-0064: e4000_probe: > >> kernel: usb 1-2: rtl2832u_tuner_attach: client ptr ffff88030a849000 > >> > >> See attached patch. > >> > >> Is there any way to return error to caller? > >> > >> Abuse platform data ptr from struct i2c_board_info and call > >> i2c_unregister_device() ? > > > > Answer to myself: best option seems to be check i2c_get_clientdata() > > pointer after i2c_new_device(). > > > > client = i2c_new_device(&d->i2c_adap, &info); > > if (client) > > if (i2c_get_clientdata(client) == NULL) > > // OOPS, I2C probe fails > > > > That is because it is set NULL in error case by really_probe() in > > drivers/base/dd.c. Error status is also cleared there with comment: > > /* > > * Ignore errors returned by ->probe so that the next driver can try > > * its luck. > > */ > > > > That is told in I2C documentation too: > > Note that starting with kernel 2.6.34, you don't have to set the `data' > > field > > to NULL in remove() or if probe() failed anymore. The i2c-core does this > > automatically on these occasions. Those are also the only times the core > > will > > touch this field. > > > > > > > > But maybe the comment for actual function, i2c_new_device, is still a > > bit misleading as it says NULL is returned for the error. All the other > > errors yes, but not for the I2C .probe() as it is reseted by device core. > > > > * This returns the new i2c client, which may be saved for later use with > > * i2c_unregister_device(); or NULL to indicate an error. > > */ > > struct i2c_client * > > i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info) > > > > > > regards > > Antti > > > > > >> > >> regards > >> Antti > >> > >> --- > >> drivers/media/tuners/e4000.c | 31 > >> +++++++++++++++++++++++++++++++ > >> drivers/media/usb/dvb-usb-v2/rtl28xxu.c | 18 ++++++++++++++++-- > >> 2 files changed, 47 insertions(+), 2 deletions(-) > >> > >> diff --git a/drivers/media/tuners/e4000.c b/drivers/media/tuners/e4000.c > >> index 54e2d8a..f4e0567 100644 > >> --- a/drivers/media/tuners/e4000.c > >> +++ b/drivers/media/tuners/e4000.c > >> @@ -442,6 +442,37 @@ err: > >> } > >> EXPORT_SYMBOL(e4000_attach); > >> > >> +static int e4000_probe(struct i2c_client *client, const struct > >> i2c_device_id *did) > >> +{ > >> + dev_info(&client->dev, "%s:\n", __func__); > >> + return -ENODEV; > >> +} > >> + > >> +static int e4000_remove(struct i2c_client *client) > >> +{ > >> + dev_info(&client->dev, "%s:\n", __func__); > >> + return 0; > >> +} > >> + > >> +static const struct i2c_device_id e4000_id[] = { > >> + {"e4000", 0}, > >> + {} > >> +}; > >> + > >> +MODULE_DEVICE_TABLE(i2c, e4000_id); > >> + > >> +static struct i2c_driver e4000_driver = { > >> + .driver = { > >> + .owner = THIS_MODULE, > >> + .name = "e4000", > >> + }, > >> + .probe = e4000_probe, > >> + .remove = e4000_remove, > >> + .id_table = e4000_id, > >> +}; > >> + > >> +module_i2c_driver(e4000_driver); > >> + > >> MODULE_DESCRIPTION("Elonics E4000 silicon tuner driver"); > >> MODULE_AUTHOR("Antti Palosaari <crope@xxxxxx>"); > >> MODULE_LICENSE("GPL"); > >> diff --git a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c > >> b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c > >> index defc491..fbbe867 100644 > >> --- a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c > >> +++ b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c > >> @@ -898,8 +898,22 @@ static int rtl2832u_tuner_attach(struct > >> dvb_usb_adapter *adap) > >> adap->fe[0]->ops.tuner_ops.get_rf_strength; > >> return 0; > >> case TUNER_RTL2832_E4000: > >> - fe = dvb_attach(e4000_attach, adap->fe[0], &d->i2c_adap, > >> - &rtl2832u_e4000_config); > >> +// fe = dvb_attach(e4000_attach, adap->fe[0], &d->i2c_adap, > >> +// &rtl2832u_e4000_config); > >> + { > >> + static const struct i2c_board_info info = { > >> + .type = "e4000", > >> + .addr = 0x64, > >> + }; > >> + struct i2c_client *client; > >> + > >> + fe = NULL; > >> + client = i2c_new_device(&d->i2c_adap, &info); > >> + if (IS_ERR_OR_NULL(client)) > >> + dev_err(&d->udev->dev, "e4000 probe failed\n"); > >> + > >> + dev_dbg(&d->udev->dev, "%s: client ptr %p\n", __func__, > >> client); > >> + } > >> break; > >> case TUNER_RTL2832_FC2580: > >> fe = dvb_attach(fc2580_attach, adap->fe[0], &d->i2c_adap, > >> -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
