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-rw-r--r--drivers/media/radio/radio-gemtek.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/drivers/media/radio/radio-gemtek.c b/drivers/media/radio/radio-gemtek.c
index f959bb7..0fcd2b0 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);
}
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