diff options
Diffstat (limited to 'board/freescale/common/ics307_clk.c')
| -rw-r--r-- | board/freescale/common/ics307_clk.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/board/freescale/common/ics307_clk.c b/board/freescale/common/ics307_clk.c index 89d8810f74..6acbc361a3 100644 --- a/board/freescale/common/ics307_clk.c +++ b/board/freescale/common/ics307_clk.c @@ -31,12 +31,81 @@ #include "pixis.h" #endif +/* define for SYS CLK or CLK1Frequency */ +#define TTL 1 +#define CLK2 0 +#define CRYSTAL 0 +#define MAX_VDW (511 + 8) +#define MAX_RDW (127 + 2) +#define MIN_VDW (4 + 8) +#define MIN_RDW (1 + 2) +#define NUM_OD_SETTING 8 +/* + * These defines cover the industrial temperature range part, + * for commercial, change below to 400000 and 55000, respectively + */ +#define MAX_VCO 360000 +#define MIN_VCO 60000 + /* decode S[0-2] to Output Divider (OD) */ static u8 ics307_s_to_od[] = { 10, 2, 8, 4, 5, 7, 3, 6 }; /* + * Find one solution to generate required frequency for SYSCLK + * out_freq: KHz, required frequency to the SYSCLK + * the result will be retuned with component RDW, VDW, OD, TTL, + * CLK2 and crystal + */ +unsigned long ics307_sysclk_calculator(unsigned long out_freq) +{ + const unsigned long input_freq = CONFIG_ICS307_REFCLK_HZ; + unsigned long vdw, rdw, odp, s_vdw = 0, s_rdw = 0, s_odp = 0, od; + unsigned long tmp_out, diff, result = 0; + int found = 0; + + for (odp = 0; odp < NUM_OD_SETTING; odp++) { + od = ics307_s_to_od[odp]; + if (od * out_freq < MIN_VCO || od * out_freq > MAX_VCO) + continue; + for (rdw = MIN_RDW; rdw <= MAX_RDW; rdw++) { + /* Calculate the VDW */ + vdw = out_freq * 1000 * od * rdw / (input_freq * 2); + if (vdw > MAX_VDW) + vdw = MAX_VDW; + if (vdw < MIN_VDW) + continue; + /* Calculate the temp out frequency */ + tmp_out = input_freq * 2 * vdw / (rdw * od * 1000); + diff = MAX(out_freq, tmp_out) - MIN(out_freq, tmp_out); + /* + * calculate the percent, the precision is 1/1000 + * If greater than 1/1000, continue + * otherwise, we think the solution is we required + */ + if (diff * 1000 / out_freq > 1) + continue; + else { + s_vdw = vdw; + s_rdw = rdw; + s_odp = odp; + found = 1; + break; + } + } + } + + if (found) + result = (s_rdw - 2) | (s_vdw - 8) << 7 | s_odp << 16 | + CLK2 << 19 | TTL << 21 | CRYSTAL << 22; + + debug("ICS307-02: RDW: %ld, VDW: %ld, OD: %d\n", s_rdw - 2, s_vdw - 8, + ics307_s_to_od[s_odp]); + return result; +} + +/* * Calculate frequency being generated by ICS307-02 clock chip based upon * the control bytes being programmed into it. */ |