V4L/DVB (13541): atbm8830: replace 64-bit division and floating point usage

Randy Dunlap wrote:
> On Mon, 30 Nov 2009 10:07:21 -0800 Randy Dunlap wrote:
>
>> Stephen Rothwell wrote:
>>> Hi all,
>>>
>>> Changes since 20091127:
>>>
>>> The v4l-dvb tree lost its conflict.
>>
>> on i386 (X86_32):
>>
>> a 'double' variable is used, causing:
>>
>> ERROR: "__floatunsidf" [drivers/media/common/tuners/max2165.ko] undefined!
>> ERROR: "__adddf3" [drivers/media/common/tuners/max2165.ko] undefined!
>> ERROR: "__fixunsdfsi" [drivers/media/common/tuners/max2165.ko] undefined!
>
>
> linux-next-20091202:
>
> still have this one (above) and similar with
> drivers/media/dvb/frontends/atbm8830.c:
>
> drivers/built-in.o: In function `atbm8830_init':
> atbm8830.c:(.text+0x9012f9): undefined reference to `__udivdi3'
> atbm8830.c:(.text+0x901384): undefined reference to `__floatunsidf'
> atbm8830.c:(.text+0x901395): undefined reference to `__muldf3'
> atbm8830.c:(.text+0x9013a5): undefined reference to `__floatunsidf'
> atbm8830.c:(.text+0x9013b2): undefined reference to `__divdf3'
> atbm8830.c:(.text+0x9013c3): undefined reference to `__muldf3'
> atbm8830.c:(.text+0x9013cd): undefined reference to `__fixunsdfsi'
>
> ---
> ~Randy
> --
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This patch replace 64-bit division by do_div() macro and remove usage of
floating point variable

Signed-off-by: David T. L. Wong <davidtlwong@gmail.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/atbm8830.c

@@ -19,6 +19,7 @@
  *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include <asm/div64.h>
 #include "dvb_frontend.h"
 
 #include "atbm8830.h"
@@ -102,8 +103,12 @@ static inline int atbm8830_reglatch_lock(struct atbm_state *priv, int lock)
 static int set_osc_freq(struct atbm_state *priv, u32 freq /*in kHz*/)
 {
 	u32 val;
+	u64 t;
 
-	val = (u64)0x100000 * freq / 30400;
+	/* 0x100000 * freq / 30.4MHz */
+	t = (u64)0x100000 * freq;
+	do_div(t, 30400);
+	val = t;
 
 	atbm8830_write_reg(priv, REG_OSC_CLK, val);
 	atbm8830_write_reg(priv, REG_OSC_CLK + 1, val >> 8);
@@ -116,14 +121,18 @@ static int set_if_freq(struct atbm_state *priv, u32 freq /*in kHz*/)
 {
 
 	u32 fs = priv->config->osc_clk_freq;
-	double t;
+	u64 t;
 	u32 val;
 	u8 dat;
 
-	t = 2 * 3.141593 * (freq - fs) / fs * (1 << 22);
-	val = t;
-
 	if (freq != 0) {
+		/* 2 * PI * (freq - fs) / fs * (2 ^ 22) */
+		t = (u64) 2 * 31416 * (freq - fs);
+		t <<= 22;
+		do_div(t, fs);
+		do_div(t, 1000);
+		val = t;
+
 		atbm8830_write_reg(priv, REG_TUNER_BASEBAND, 1);
 		atbm8830_write_reg(priv, REG_IF_FREQ, val);
 		atbm8830_write_reg(priv, REG_IF_FREQ+1, val >> 8);