alistair23-linux/drivers/media/dvb-frontends/zl10036.h

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/**
* Driver for Zarlink ZL10036 DVB-S silicon tuner
*
* Copyright (C) 2006 Tino Reichardt
* Copyright (C) 2007-2009 Matthias Schwarzott <zzam@gentoo.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License Version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef DVB_ZL10036_H
#define DVB_ZL10036_H
#include <linux/i2c.h>
#include <media/dvb_frontend.h>
struct zl10036_config {
u8 tuner_address;
int rf_loop_enable;
};
[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 10:12:42 -07:00
#if IS_REACHABLE(CONFIG_DVB_ZL10036)
/**
* Attach a zl10036 tuner to the supplied frontend structure.
*
* @fe: Frontend to attach to.
* @config: zl10036_config structure.
* @i2c: pointer to struct i2c_adapter.
* return: FE pointer on success, NULL on failure.
*/
extern struct dvb_frontend *zl10036_attach(struct dvb_frontend *fe,
const struct zl10036_config *config, struct i2c_adapter *i2c);
#else
static inline struct dvb_frontend *zl10036_attach(struct dvb_frontend *fe,
const struct zl10036_config *config, struct i2c_adapter *i2c)
{
printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
return NULL;
}
#endif
#endif /* DVB_ZL10036_H */