linux/drivers/media/dvb-frontends/mt352.h

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/*
* Driver for Zarlink DVB-T MT352 demodulator
*
* Written by Holger Waechtler <holger@qanu.de>
* and Daniel Mack <daniel@qanu.de>
*
* AVerMedia AVerTV DVB-T 771 support by
* Wolfram Joost <dbox2@frokaschwei.de>
*
* Support for Samsung TDTC9251DH01C(M) tuner
* Copyright (C) 2004 Antonio Mancuso <antonio.mancuso@digitaltelevision.it>
* Amauri Celani <acelani@essegi.net>
*
* DVICO FusionHDTV DVB-T1 and DVICO FusionHDTV DVB-T Lite support by
* Christopher Pascoe <c.pascoe@itee.uq.edu.au>
*
* 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.
*/
#ifndef MT352_H
#define MT352_H
#include <linux/dvb/frontend.h>
struct mt352_config
{
/* the demodulator's i2c address */
u8 demod_address;
/* frequencies in kHz */
int adc_clock; // default: 20480
int if2; // default: 36166
/* set if no pll is connected to the secondary i2c bus */
int no_tuner;
/* Initialise the demodulator and PLL. Cannot be NULL */
int (*demod_init)(struct dvb_frontend* fe);
};
[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_MT352)
extern struct dvb_frontend* mt352_attach(const struct mt352_config* config,
struct i2c_adapter* i2c);
#else
static inline struct dvb_frontend* mt352_attach(const struct mt352_config* config,
struct i2c_adapter* i2c)
{
printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
return NULL;
}
#endif // CONFIG_DVB_MT352
static inline int mt352_write(struct dvb_frontend *fe, const u8 buf[], int len) {
int r = 0;
if (fe->ops.write)
r = fe->ops.write(fe, buf, len);
return r;
}
#endif // MT352_H