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In the media drivers, the v4l2 core knows about all submodules and calls into them from a common function. However this cannot work if the modules that get called are loadable and the core is built-in. In that case we get drivers/built-in.o: In function `set_type': drivers/media/v4l2-core/tuner-core.c:301: undefined reference to `tea5767_attach' drivers/media/v4l2-core/tuner-core.c:307: undefined reference to `tea5761_attach' drivers/media/v4l2-core/tuner-core.c:349: undefined reference to `tda9887_attach' drivers/media/v4l2-core/tuner-core.c:405: undefined reference to `xc4000_attach' This was working previously, until the IS_ENABLED() macro was used to replace the construct like #if defined(CONFIG_DVB_CX24110) || (defined(CONFIG_DVB_CX24110_MODULE) && defined(MODULE)) with the difference that the new code no longer checks whether it is being built as a loadable module itself. To fix this, this new patch adds an 'IS_REACHABLE' macro, which evaluates true in exactly the condition that was used previously. The downside of this is that this trades an obvious link error for a more subtle runtime failure, but it is clear that the change that introduced the link error was unintentional and it seems better to revert it for now. Also, a similar change was originally created by Trent Piepho and then reverted by teh change to the IS_ENABLED macro. Ideally Kconfig would be used to avoid the case of a broken dependency, or the code restructured in a way to turn around the dependency, but either way would require much larger changes here. Fixes:7b34be71db("[media] use IS_ENABLED() macro") See-also:c5dec9fb24("V4L/DVB (4751): Fix DBV_FE_CUSTOMISE for card drivers compiled into kernel") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
59 lines
1.6 KiB
C
59 lines
1.6 KiB
C
/*
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* Elonics R820T silicon tuner driver
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*
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* Copyright (C) 2012 Antti Palosaari <crope@iki.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef R820T_H
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#define R820T_H
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#include <linux/kconfig.h>
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#include "dvb_frontend.h"
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enum r820t_chip {
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CHIP_R820T,
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CHIP_R620D,
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CHIP_R828D,
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CHIP_R828,
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CHIP_R828S,
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CHIP_R820C,
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};
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struct r820t_config {
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u8 i2c_addr; /* 0x34 */
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u32 xtal;
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enum r820t_chip rafael_chip;
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unsigned max_i2c_msg_len;
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bool use_diplexer;
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bool use_predetect;
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};
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#if IS_REACHABLE(CONFIG_MEDIA_TUNER_R820T)
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struct dvb_frontend *r820t_attach(struct dvb_frontend *fe,
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struct i2c_adapter *i2c,
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const struct r820t_config *cfg);
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#else
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static inline struct dvb_frontend *r820t_attach(struct dvb_frontend *fe,
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struct i2c_adapter *i2c,
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const struct r820t_config *cfg)
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{
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pr_warn("%s: driver disabled by Kconfig\n", __func__);
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return NULL;
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}
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#endif
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#endif
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