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linux-next/drivers/media/dvb-frontends/dvb-pll.h
Arnd Bergmann 9b174527e7 [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: 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>
2015-04-08 15:02:07 -03:00

58 lines
1.7 KiB
C

/*
* descriptions + helper functions for simple dvb plls.
*/
#ifndef __DVB_PLL_H__
#define __DVB_PLL_H__
#include <linux/i2c.h>
#include "dvb_frontend.h"
#define DVB_PLL_UNDEFINED 0
#define DVB_PLL_THOMSON_DTT7579 1
#define DVB_PLL_THOMSON_DTT759X 2
#define DVB_PLL_LG_Z201 3
#define DVB_PLL_UNKNOWN_1 4
#define DVB_PLL_TUA6010XS 5
#define DVB_PLL_ENV57H1XD5 6
#define DVB_PLL_TUA6034 7
#define DVB_PLL_TDA665X 8
#define DVB_PLL_TDED4 9
#define DVB_PLL_TDHU2 10
#define DVB_PLL_SAMSUNG_TBMV 11
#define DVB_PLL_PHILIPS_SD1878_TDA8261 12
#define DVB_PLL_OPERA1 13
#define DVB_PLL_SAMSUNG_DTOS403IH102A 14
#define DVB_PLL_SAMSUNG_TDTC9251DH0 15
#define DVB_PLL_SAMSUNG_TBDU18132 16
#define DVB_PLL_SAMSUNG_TBMU24112 17
#define DVB_PLL_TDEE4 18
#define DVB_PLL_THOMSON_DTT7520X 19
/**
* Attach a dvb-pll to the supplied frontend structure.
*
* @param fe Frontend to attach to.
* @param pll_addr i2c address of the PLL (if used).
* @param i2c i2c adapter to use (set to NULL if not used).
* @param pll_desc_id dvb_pll_desc to use.
* @return Frontend pointer on success, NULL on failure
*/
#if IS_REACHABLE(CONFIG_DVB_PLL)
extern struct dvb_frontend *dvb_pll_attach(struct dvb_frontend *fe,
int pll_addr,
struct i2c_adapter *i2c,
unsigned int pll_desc_id);
#else
static inline struct dvb_frontend *dvb_pll_attach(struct dvb_frontend *fe,
int pll_addr,
struct i2c_adapter *i2c,
unsigned int pll_desc_id)
{
printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
return NULL;
}
#endif
#endif