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cirrusfb: drop clock fields from cirrusfb_regs structure 

Move call to pixclock calculation into the cirrusfb_set_par_foo().  It
makes copy of clock registers redundant.

Simplify clock calculations further.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Krzysztof Helt 2008-10-15 22:03:40 -07:00 committed by Linus Torvalds
parent 9a85cf51fb
commit dafa32c5a1
1 changed files with 21 additions and 29 deletions
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50
drivers/video/cirrusfb.c
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@ -327,10 +327,6 @@ static const struct {
#endif /* CONFIG_ZORRO */
struct cirrusfb_regs {
long freq;
long nom;
long den;
long div;
long multiplexing;
long mclk;
long divMCLK;
@ -429,9 +425,7 @@ static void cirrusfb_RectFill(u8 __iomem *regbase, int bits_per_pixel,
u_short width, u_short height,
u_char color, u_short line_length);
static void bestclock(long freq, long *best,
long *nom, long *den,
long *div, long maxfreq);
static void bestclock(long freq, int *nom, int *den, int *div);
#ifdef CIRRUSFB_DEBUG
static void cirrusfb_dump(void);
@ -711,9 +705,6 @@ static int cirrusfb_decode_var(const struct fb_var_screeninfo *var,
break;
}
#endif
bestclock(freq, &regs->freq, &regs->nom, &regs->den, &regs->div,
maxclock);
regs->mclk = cirrusfb_get_mclk(freq, var->bits_per_pixel,
&regs->divMCLK);
@ -756,6 +747,8 @@ static int cirrusfb_set_par_foo(struct fb_info *info)
const struct cirrusfb_board_info_rec *bi;
int hdispend, hsyncstart, hsyncend, htotal;
int yres, vdispend, vsyncstart, vsyncend, vtotal;
long freq;
int nom, den, div;
DPRINTK("ENTER\n");
DPRINTK("Requested mode: %dx%dx%d\n",
@ -903,14 +896,17 @@ static int cirrusfb_set_par_foo(struct fb_info *info)
DPRINTK("CRT1a: %d\n", tmp);
vga_wcrt(regbase, CL_CRT1A, tmp);
freq = PICOS2KHZ(var->pixclock);
bestclock(freq, &nom, &den, &div);
/* set VCLK0 */
/* hardware RefClock: 14.31818 MHz */
/* formula: VClk = (OSC * N) / (D * (1+P)) */
/* Example: VClk = (14.31818 * 91) / (23 * (1+1)) = 28.325 MHz */
vga_wseq(regbase, CL_SEQRB, regs.nom);
tmp = regs.den << 1;
if (regs.div != 0)
vga_wseq(regbase, CL_SEQRB, nom);
tmp = den << 1;
if (div != 0)
tmp |= 1;
/* 6 bit denom; ONLY 5434!!! (bugged me 10 days) */
@ -2923,16 +2919,14 @@ static void cirrusfb_RectFill(u8 __iomem *regbase, int bits_per_pixel,
* bestclock() - determine closest possible clock lower(?) than the
* desired pixel clock
**************************************************************************/
static void bestclock(long freq, long *best, long *nom,
long *den, long *div, long maxfreq)
static void bestclock(long freq, int *nom, int *den, int *div)
{
long n, h, d, f;
int n, d;
long h, diff;
assert(best != NULL);
assert(nom != NULL);
assert(den != NULL);
assert(div != NULL);
assert(maxfreq > 0);
*nom = 0;
*den = 0;
@ -2943,16 +2937,12 @@ static void bestclock(long freq, long *best, long *nom,
if (freq < 8000)
freq = 8000;
if (freq > maxfreq)
freq = maxfreq;
*best = 0;
f = freq * 10;
diff = freq;
for (n = 32; n < 128; n++) {
int s = 0;
d = (143181 * n) / f;
d = (14318 * n) / freq;
if ((d >= 7) && (d <= 63)) {
int temp = d;
@ -2961,8 +2951,9 @@ static void bestclock(long freq, long *best, long *nom,
temp >>= 1;
}
h = ((14318 * n) / temp) >> s;
if (abs(h - freq) < abs(*best - freq)) {
*best = h;
h = h > freq ? h - freq : freq - h;
if (h < diff) {
diff = h;
*nom = n;
*den = temp;
*div = s;
@ -2975,8 +2966,9 @@ static void bestclock(long freq, long *best, long *nom,
d >>= 1;
}
h = ((14318 * n) / d) >> s;
if (abs(h - freq) < abs(*best - freq)) {
*best = h;
h = h > freq ? h - freq : freq - h;
if (h < diff) {
diff = h;
*nom = n;
*den = d;
*div = s;
@ -2985,7 +2977,7 @@ static void bestclock(long freq, long *best, long *nom,
}
DPRINTK("Best possible values for given frequency:\n");
DPRINTK(" best: %ld kHz nom: %ld den: %ld div: %ld\n",
DPRINTK(" freq: %ld kHz nom: %d den: %d div: %d\n",
freq, *nom, *den, *div);
DPRINTK("EXIT\n");