Antti Palosaari <crope@xxxxxx> writes: > On 06/03/2011 03:50 PM, BjÃrn Mork wrote: > >> This probably means that a generic i2c_tuner wrapper, similar to >> dvb_attach, would be useful. > > For the cxd2820r it is also possible to return I2C adapter as pointer > from dvb_attach like pointer to FE0 is carried for FE1 > dvb_attach. What you think about that? I don't feel competent to answer that at all. It does seem like overloading an existing interface, but it might be OK. I just grepped a bit around for EXPORT_SYMBOL of anything except foo_attach, and found that there are a few frontend drivers which exports multiple symbols: bjorn@canardo:/usr/local/src/git/linux-2.6$ grep EXPORT_SYMBOL drivers/media/dvb/frontends/*.c|grep -v _attach drivers/media/dvb/frontends/cx24113.c:EXPORT_SYMBOL(cx24113_agc_callback); drivers/media/dvb/frontends/cx24123.c:EXPORT_SYMBOL(cx24123_get_tuner_i2c_adapter); drivers/media/dvb/frontends/cxd2820r_core.c:EXPORT_SYMBOL(cxd2820r_get_tuner_i2c_adapter); drivers/media/dvb/frontends/dib0070.c:EXPORT_SYMBOL(dib0070_ctrl_agc_filter); drivers/media/dvb/frontends/dib0070.c:EXPORT_SYMBOL(dib0070_get_rf_output); drivers/media/dvb/frontends/dib0070.c:EXPORT_SYMBOL(dib0070_set_rf_output); drivers/media/dvb/frontends/dib0070.c:EXPORT_SYMBOL(dib0070_wbd_offset); drivers/media/dvb/frontends/dib0090.c:EXPORT_SYMBOL(dib0090_dcc_freq); drivers/media/dvb/frontends/dib0090.c:EXPORT_SYMBOL(dib0090_pwm_gain_reset); drivers/media/dvb/frontends/dib0090.c:EXPORT_SYMBOL(dib0090_gain_control); drivers/media/dvb/frontends/dib0090.c:EXPORT_SYMBOL(dib0090_get_current_gain); drivers/media/dvb/frontends/dib0090.c:EXPORT_SYMBOL(dib0090_get_wbd_offset); drivers/media/dvb/frontends/dib0090.c:EXPORT_SYMBOL(dib0090_get_tune_state); drivers/media/dvb/frontends/dib0090.c:EXPORT_SYMBOL(dib0090_set_tune_state); drivers/media/dvb/frontends/dib0090.c:EXPORT_SYMBOL(dib0090_register); drivers/media/dvb/frontends/dib0090.c:EXPORT_SYMBOL(dib0090_fw_register); drivers/media/dvb/frontends/dib3000mc.c:EXPORT_SYMBOL(dib3000mc_get_tuner_i2c_master); drivers/media/dvb/frontends/dib3000mc.c:EXPORT_SYMBOL(dib3000mc_pid_control); drivers/media/dvb/frontends/dib3000mc.c:EXPORT_SYMBOL(dib3000mc_pid_parse); drivers/media/dvb/frontends/dib3000mc.c:EXPORT_SYMBOL(dib3000mc_set_config); drivers/media/dvb/frontends/dib3000mc.c:EXPORT_SYMBOL(dib3000mc_i2c_enumeration); drivers/media/dvb/frontends/dib7000m.c:EXPORT_SYMBOL(dib7000m_get_i2c_master); drivers/media/dvb/frontends/dib7000m.c:EXPORT_SYMBOL(dib7000m_pid_filter_ctrl); drivers/media/dvb/frontends/dib7000m.c:EXPORT_SYMBOL(dib7000m_pid_filter); drivers/media/dvb/frontends/dib7000m.c:EXPORT_SYMBOL(dib7000m_i2c_enumeration); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7000p_set_wbd_ref); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7000p_update_pll); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7000p_set_gpio); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7000p_ctrl_timf); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7000pc_detection); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7000p_get_i2c_master); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7000p_pid_filter_ctrl); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7000p_pid_filter); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7000p_i2c_enumeration); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7090_get_i2c_tuner); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7090_tuner_sleep); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7090_agc_restart); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7090_get_adc_power); drivers/media/dvb/frontends/dib7000p.c:EXPORT_SYMBOL(dib7090_slave_reset); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_set_wbd_ref); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_set_gpio); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_pwm_agc_reset); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_get_adc_power); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_get_tune_state); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_set_tune_state); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_set_slave_frontend); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_remove_slave_frontend); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_get_slave_frontend); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_i2c_enumeration); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_get_i2c_master); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_pid_filter_ctrl); drivers/media/dvb/frontends/dib8000.c:EXPORT_SYMBOL(dib8000_pid_filter); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_fw_set_component_bus_speed); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_get_tuner_interface); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_get_component_bus_interface); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_get_i2c_master); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_set_i2c_adapter); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_set_gpio); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_fw_pid_filter_ctrl); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_fw_pid_filter); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_firmware_post_pll_init); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_i2c_enumeration); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_set_slave_frontend); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_remove_slave_frontend); drivers/media/dvb/frontends/dib9000.c:EXPORT_SYMBOL(dib9000_get_slave_frontend); drivers/media/dvb/frontends/dibx000_common.c:EXPORT_SYMBOL(dibx000_i2c_set_speed); drivers/media/dvb/frontends/dibx000_common.c:EXPORT_SYMBOL(dibx000_get_i2c_adapter); drivers/media/dvb/frontends/dibx000_common.c:EXPORT_SYMBOL(dibx000_reset_i2c_master); drivers/media/dvb/frontends/dibx000_common.c:EXPORT_SYMBOL(dibx000_init_i2c_master); drivers/media/dvb/frontends/dibx000_common.c:EXPORT_SYMBOL(dibx000_exit_i2c_master); drivers/media/dvb/frontends/dibx000_common.c:EXPORT_SYMBOL(systime); drivers/media/dvb/frontends/drxd_hard.c:EXPORT_SYMBOL(drxd_config_i2c); drivers/media/dvb/frontends/s5h1420.c:EXPORT_SYMBOL(s5h1420_get_tuner_i2c_adapter); drivers/media/dvb/frontends/stv090x.c:EXPORT_SYMBOL(stv090x_set_gpio); Which does show up as hard dependencies on your typical Debian installation (which does set CONFIG_MEDIA_ATTACH): bjorn@nemi:~$ modinfo -F depends dvb-usb-dib0700 dib8000,dvb-usb,i2c-core,dib0070,dib3000mc,usbcore,dib7000p,dib7000m So it looks like this problem is much more widespread than I initially thought, and it may therefore be perfectly OK to do what you did. However, the em28xx-dvb driver can be used with a large number of frontends and we certainly don't want them all as hard dependencies. I think it's time for someone with authority to state what is acceptable and what is not, with regard to frontends, tuners, dvb_attach(), EXPORT_SYMBOL and CONFIG_MEDIA_ATTACH. For all I know, this may already be documented somewhere. If so, please point me there. BjÃrn -- 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
