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remarkable-linux/drivers/media/dvb-frontends/isl6421.h

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/*
* isl6421.h - driver for lnb supply and control ic ISL6421
*
* Copyright (C) 2006 Andrew de Quincey
* Copyright (C) 2006 Oliver Endriss
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
*
* 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.
*
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
* Or, point your browser to http://www.gnu.org/copyleft/gpl.html
*
*
* the project's page is at https://linuxtv.org
*/
#ifndef _ISL6421_H
#define _ISL6421_H
#include <linux/dvb/frontend.h>
/* system register bits */
#define ISL6421_OLF1 0x01
#define ISL6421_EN1 0x02
#define ISL6421_VSEL1 0x04
#define ISL6421_LLC1 0x08
#define ISL6421_ENT1 0x10
#define ISL6421_ISEL1 0x20
#define ISL6421_DCL 0x40
[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_ISL6421)
/* override_set and override_clear control which system register bits (above) to always set & clear */
extern struct dvb_frontend *isl6421_attach(struct dvb_frontend *fe, struct i2c_adapter *i2c, u8 i2c_addr,
u8 override_set, u8 override_clear, bool override_tone);
#else
static inline struct dvb_frontend *isl6421_attach(struct dvb_frontend *fe, struct i2c_adapter *i2c, u8 i2c_addr,
u8 override_set, u8 override_clear, bool override_tone)
{
printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
return NULL;
}
#endif // CONFIG_DVB_ISL6421
#endif