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staging: sm750fb: simplify PLL divisors calculations 

The calcPllValues currently uses arrays of PLL parametres that contain
possible PLL control register field values and redundant data that is
calculated according to those values. The usage of these arrays can be
replaced with simple arithmetics.

Signed-off-by: Mike Rapoport <mike.rapoport@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mike Rapoport 2015-10-22 09:38:40 +03:00 committed by Greg Kroah-Hartman
parent cfac7d6a70
commit a61dc139ce
1 changed files with 10 additions and 34 deletions
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44
drivers/staging/sm750fb/ddk750_chip.c
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@ -303,33 +303,14 @@ int ddk750_initHw(initchip_param_t *pInitParam)
*/
unsigned int calcPllValue(unsigned int request_orig, pll_value_t *pll)
{
/* used for primary and secondary channel pixel clock pll */
static pllcalparam xparm_PIXEL[] = {
/* 2^0 = 1*/ {0, 0, 0, 1},
/* 2^ 1 =2*/ {1, 0, 1, 2},
/* 2^ 2 = 4*/ {2, 0, 2, 4},
{3, 0, 3, 8},
{4, 1, 3, 16},
{5, 2, 3, 32},
/* 2^6 = 64 */ {6, 3, 3, 64},
};
/* used for MXCLK (chip clock) */
static pllcalparam xparm_MXCLK[] = {
/* 2^0 = 1*/ {0, 0, 0, 1},
/* 2^ 1 =2*/ {1, 0, 1, 2},
/* 2^ 2 = 4*/ {2, 0, 2, 4},
{3, 0, 3, 8},
};
/* as sm750 register definition, N located in 2,15 and M located in 1,255 */
int N, M, X, d;
int xcnt;
int mini_diff;
unsigned int RN, quo, rem, fl_quo;
unsigned int input, request;
unsigned int tmpClock, ret;
pllcalparam *xparm;
const int max_OD = 3;
int max_d;
if (getChipType() == SM750LE) {
/* SM750LE don't have prgrammable PLL and M/N values to work on.
@ -343,15 +324,8 @@ unsigned int calcPllValue(unsigned int request_orig, pll_value_t *pll)
input = pll->inputFreq / 1000;
/* for MXCLK register , no POD provided, so need be treated differently */
if (pll->clockType != MXCLK_PLL) {
xparm = &xparm_PIXEL[0];
xcnt = ARRAY_SIZE(xparm_PIXEL);
} else {
xparm = &xparm_MXCLK[0];
xcnt = ARRAY_SIZE(xparm_MXCLK);
}
if (pll->clockType == MXCLK_PLL)
max_d = 3;
for (N = 15; N > 1; N--) {
/* RN will not exceed maximum long if @request <= 285 MHZ (for 32bit cpu) */
@ -360,8 +334,8 @@ unsigned int calcPllValue(unsigned int request_orig, pll_value_t *pll)
rem = RN % input;/* rem always small than 14318181 */
fl_quo = (rem * 10000 / input);
for (d = xcnt - 1; d >= 0; d--) {
X = xparm[d].value;
for (d = max_d; d >= 0; d--) {
X = (1 << d);
M = quo * X;
M += fl_quo * X / 10000;
/* round step */
@ -374,8 +348,10 @@ unsigned int calcPllValue(unsigned int request_orig, pll_value_t *pll)
if (diff < mini_diff) {
pll->M = M;
pll->N = N;
pll->OD = xparm[d].od;
pll->POD = xparm[d].pod;
pll->POD = 0;
if (d > max_OD)
pll->POD = d - max_OD;
pll->OD = d - pll->POD;
mini_diff = diff;
ret = tmpClock;
}