linux/drivers/media/dvb-frontends/mb86a16.h

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
Fujitsu MB86A16 DVB-S/DSS DC Receiver driver
Copyright (C) Manu Abraham (abraham.manu@gmail.com)
*/
#ifndef __MB86A16_H
#define __MB86A16_H
#include <linux/dvb/frontend.h>
#include <media/dvb_frontend.h>
struct mb86a16_config {
u8 demod_address;
int (*set_voltage)(struct dvb_frontend *fe,
enum fe_sec_voltage voltage);
};
[media] Add and use IS_REACHABLE macro 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: 7b34be71db53 ("[media] use IS_ENABLED() macro") See-also: c5dec9fb248e ("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>
2015-02-18 17:12:42 +00:00
#if IS_REACHABLE(CONFIG_DVB_MB86A16)
extern struct dvb_frontend *mb86a16_attach(const struct mb86a16_config *config,
struct i2c_adapter *i2c_adap);
#else
static inline struct dvb_frontend *mb86a16_attach(const struct mb86a16_config *config,
struct i2c_adapter *i2c_adap)
{
printk(KERN_WARNING "%s: Driver disabled by Kconfig\n", __func__);
return NULL;
}
#endif /* CONFIG_DVB_MB86A16 */
#endif /* __MB86A16_H */