forked from Minki/linux
V4L/DVB (9449): Code Simplification: use do_div() instead
Signed-off-by: Reinhard Nissl <rnissl@gmx.de> Signed-off-by: Manu Abraham <manu@linuxtv.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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@ -23,27 +23,12 @@
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#include "stb0899_priv.h"
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#include "stb0899_reg.h"
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/*
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* BinaryFloatDiv
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* float division with integer
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*/
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static long BinaryFloatDiv(long n1, long n2, int precision)
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inline u32 stb0899_do_div(u64 n, u32 d)
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{
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int i = 0;
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long result = 0;
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/* wrap do_div() for ease of use */
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while (i <= precision) {
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if (n1 < n2) {
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result *= 2;
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n1 *= 2;
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} else {
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result = result * 2 + 1;
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n1 = (n1 - n2) * 2;
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}
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i++;
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}
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return result;
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do_div(n, d);
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return n;
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}
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/*
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@ -52,15 +37,15 @@ static long BinaryFloatDiv(long n1, long n2, int precision)
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*/
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static u32 stb0899_calc_srate(u32 master_clk, u8 *sfr)
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{
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u32 tmp, tmp2, mclk;
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u64 tmp;
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mclk = master_clk / 4096L; /* MasterClock * 10 / 2^20 */
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tmp = (((u32) sfr[0] << 12) + ((u32) sfr[1] << 4)) / 16;
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/* srate = (SFR * master_clk) >> 20 */
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tmp *= mclk;
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tmp /= 16;
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tmp2 = ((u32) sfr[2] * mclk) / 256;
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tmp += tmp2;
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/* sfr is of size 20 bit, stored with an offset of 4 bit */
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tmp = (((u32)sfr[0]) << 16) | (((u32)sfr[1]) << 8) | sfr[2];
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tmp &= ~0xf;
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tmp *= master_clk;
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tmp >>= 24;
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return tmp;
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}
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@ -72,7 +57,7 @@ static u32 stb0899_calc_srate(u32 master_clk, u8 *sfr)
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u32 stb0899_get_srate(struct stb0899_state *state)
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{
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struct stb0899_internal *internal = &state->internal;
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u8 sfr[4];
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u8 sfr[3];
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stb0899_read_regs(state, STB0899_SFRH, sfr, 3);
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@ -101,16 +86,30 @@ static u32 stb0899_set_srate(struct stb0899_state *state, u32 master_clk, u32 sr
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*/
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// srate_up += (srate_up * 3) / 100;
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tmp = BinaryFloatDiv(srate, master_clk, 20);
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// tmp_up = BinaryFloatDiv(srate_up, master_clk, 20);
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/*
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* srate = (SFR * master_clk) >> 20
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* <=>
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* SFR = srate << 20 / master_clk
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*
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* rounded:
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* SFR = (srate << 21 + master_clk) / (2 * master_clk)
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*
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* stored as 20 bit number with an offset of 4 bit:
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* sfr = SFR << 4;
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*/
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// tmp_up = stb0899_do_div((((u64)srate_up) << 21) + master_clk, 2 * master_clk);
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// tmp_up <<= 4;
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// sfr_up[0] = (tmp_up >> 12) & 0xff;
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// sfr_up[1] = (tmp_up >> 4) & 0xff;
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// sfr_up[2] = tmp_up & 0x0f;
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tmp = stb0899_do_div((((u64)srate) << 21) + master_clk, 2 * master_clk);
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tmp <<= 4;
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sfr[0] = (tmp >> 12) & 0xff;
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sfr[1] = (tmp >> 4) & 0xff;
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sfr[2] = (tmp << 4) & 0xf0;
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// sfr_up[0] = tmp_up >> 16;
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// sfr_up[1] = tmp_up >> 8;
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// sfr_up[2] = tmp_up;
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sfr[0] = tmp >> 16;
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sfr[1] = tmp >> 8;
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sfr[2] = tmp;
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// stb0899_write_regs(state, STB0899_SFRUPH, sfr_up, 3);
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stb0899_write_regs(state, STB0899_SFRH, sfr, 3);
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