diff options
Diffstat (limited to 'drivers/media/radio')
| -rw-r--r-- | drivers/media/radio/radio-gemtek.c | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/drivers/media/radio/radio-gemtek.c b/drivers/media/radio/radio-gemtek.c index f959bb71c46..0fcd2b09218 100644 --- a/drivers/media/radio/radio-gemtek.c +++ b/drivers/media/radio/radio-gemtek.c @@ -89,6 +89,14 @@ module_param(radio_nr, int, 0444); #define GEMTEK_LOWFREQ (87*16000) #define GEMTEK_HIGHFREQ (108*16000) +/* + * Frequency calculation constants. Intermediate frequency 10.52 MHz (nominal + * value 10.7 MHz), reference divisor 6.39 kHz (nominal 6.25 kHz). + */ +#define FSCALE 8 +#define IF_OFFSET ((unsigned int)(10.52 * 16000 * (1<<FSCALE))) +#define REF_FREQ ((unsigned int)(6.39 * 16 * (1<<FSCALE))) + #define GEMTEK_CK 0x01 /* Clock signal */ #define GEMTEK_DA 0x02 /* Serial data */ #define GEMTEK_CE 0x04 /* Chip enable */ @@ -219,14 +227,11 @@ static void gemtek_bu2614_transmit(struct gemtek_device *dev) } /* - * Convert FM-frequency for BU2614FS (3.125 KHz STDF expected). + * Calculate divisor from FM-frequency for BU2614FS (3.125 KHz STDF expected). */ -static inline void gemtek_convfreq(unsigned long *freq) +static unsigned long gemtek_convfreq(unsigned long freq) { - (*freq) /= 160; - (*freq) += 1052; /* FMIN, 10.52 MHz */ - (*freq) *= 1565; /* STDF, 1 / 156.5 = 0.00639 */ - (*freq) /= 1000; + return ((freq<<FSCALE) + IF_OFFSET + REF_FREQ/2) / REF_FREQ; } /* @@ -253,10 +258,8 @@ static void gemtek_setfreq(struct gemtek_device *dev, unsigned long freq) gemtek_bu2614_set(dev, BU2614_FMUN, 1); /* GT bit set */ gemtek_bu2614_set(dev, BU2614_TEST, 0); - gemtek_convfreq(&freq); - gemtek_bu2614_set(dev, BU2614_STDF, GEMTEK_STDF_3_125_KHZ); - gemtek_bu2614_set(dev, BU2614_FREQ, freq); + gemtek_bu2614_set(dev, BU2614_FREQ, gemtek_convfreq(freq)); gemtek_bu2614_transmit(dev); } |