diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/media/dvb-frontends/cx24123.c | 28 |
1 files changed, 7 insertions, 21 deletions
diff --git a/drivers/media/dvb-frontends/cx24123.c b/drivers/media/dvb-frontends/cx24123.c index 68c88ab58e7..a771da3e9f9 100644 --- a/drivers/media/dvb-frontends/cx24123.c +++ b/drivers/media/dvb-frontends/cx24123.c @@ -26,6 +26,7 @@ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> +#include <asm/div64.h> #include "dvb_frontend.h" #include "cx24123.h" @@ -452,7 +453,8 @@ static u32 cx24123_int_log2(u32 a, u32 b) static int cx24123_set_symbolrate(struct cx24123_state *state, u32 srate) { - u32 tmp, sample_rate, ratio, sample_gain; + u64 tmp; + u32 sample_rate, ratio, sample_gain; u8 pll_mult; /* check if symbol rate is within limits */ @@ -482,27 +484,11 @@ static int cx24123_set_symbolrate(struct cx24123_state *state, u32 srate) sample_rate = pll_mult * XTAL; - /* - SYSSymbolRate[21:0] = (srate << 23) / sample_rate - - We have to use 32 bit unsigned arithmetic without precision loss. - The maximum srate is 45000000 or 0x02AEA540. This number has - only 6 clear bits on top, hence we can shift it left only 6 bits - at a time. Borrowed from cx24110.c - */ - - tmp = srate << 6; - ratio = tmp / sample_rate; - - tmp = (tmp % sample_rate) << 6; - ratio = (ratio << 6) + (tmp / sample_rate); - - tmp = (tmp % sample_rate) << 6; - ratio = (ratio << 6) + (tmp / sample_rate); - - tmp = (tmp % sample_rate) << 5; - ratio = (ratio << 5) + (tmp / sample_rate); + /* SYSSymbolRate[21:0] = (srate << 23) / sample_rate */ + tmp = ((u64)srate) << 23; + do_div(tmp, sample_rate); + ratio = (u32) tmp; cx24123_writereg(state, 0x01, pll_mult * 6); |