linux/drivers/media/dvb-frontends/cxd2820r.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

95 lines
2.3 KiB
C

/*
* Sony CXD2820R demodulator driver
*
* Copyright (C) 2010 Antti Palosaari <crope@iki.fi>
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef CXD2820R_H
#define CXD2820R_H
#include <linux/kconfig.h>
#include <linux/dvb/frontend.h>
#define CXD2820R_GPIO_D (0 << 0) /* disable */
#define CXD2820R_GPIO_E (1 << 0) /* enable */
#define CXD2820R_GPIO_O (0 << 1) /* output */
#define CXD2820R_GPIO_I (1 << 1) /* input */
#define CXD2820R_GPIO_L (0 << 2) /* output low */
#define CXD2820R_GPIO_H (1 << 2) /* output high */
#define CXD2820R_TS_SERIAL 0x08
#define CXD2820R_TS_SERIAL_MSB 0x28
#define CXD2820R_TS_PARALLEL 0x30
#define CXD2820R_TS_PARALLEL_MSB 0x70
struct cxd2820r_config {
/* Demodulator I2C address.
* Driver determines DVB-C slave I2C address automatically from master
* address.
* Default: none, must set
* Values: 0x6c, 0x6d
*/
u8 i2c_address;
/* TS output mode.
* Default: none, must set.
* Values:
*/
u8 ts_mode;
/* TS clock inverted.
* Default: 0
* Values: 0, 1
*/
bool ts_clock_inv;
/* IF AGC polarity.
* Default: 0
* Values: 0, 1
*/
bool if_agc_polarity;
/* Spectrum inversion.
* Default: 0
* Values: 0, 1
*/
bool spec_inv;
};
#if IS_REACHABLE(CONFIG_DVB_CXD2820R)
extern struct dvb_frontend *cxd2820r_attach(
const struct cxd2820r_config *config,
struct i2c_adapter *i2c,
int *gpio_chip_base
);
#else
static inline struct dvb_frontend *cxd2820r_attach(
const struct cxd2820r_config *config,
struct i2c_adapter *i2c,
int *gpio_chip_base
)
{
printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
return NULL;
}
#endif
#endif /* CXD2820R_H */