diff options
Diffstat (limited to 'arch/powerpc/boards/freescale-p1022ds/ics307_clk.c')
-rw-r--r-- | arch/powerpc/boards/freescale-p1022ds/ics307_clk.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/arch/powerpc/boards/freescale-p1022ds/ics307_clk.c b/arch/powerpc/boards/freescale-p1022ds/ics307_clk.c new file mode 100644 index 0000000000..f7c5bbde99 --- /dev/null +++ b/arch/powerpc/boards/freescale-p1022ds/ics307_clk.c @@ -0,0 +1,46 @@ +/* + * Copyright 2010-2011 Freescale Semiconductor, Inc. + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <common.h> +#include <asm/io.h> + +/* decode S[0-2] to Output Divider (OD) */ +static u8 ics307_s_to_od[] = { + 10, 2, 8, 4, 5, 7, 3, 6 +}; + +/* Calculate frequency being generated by ICS307-02 clock chip. */ +unsigned long ics307_clk_freq(unsigned int reg) +{ + const unsigned long input_freq = 33333000; + void __iomem *fpga_base = IOMEM(CFG_PIXIS_BASE); + unsigned char cw0, cw1, cw2; + unsigned long vdw, rdw, od, freq; + + cw0 = in_8(fpga_base + reg); + cw1 = in_8(fpga_base + reg + 1); + cw2 = in_8(fpga_base + reg + 2); + vdw = ((cw1 << 1) & 0x1fe) + ((cw2 >> 7) & 1); + rdw = cw2 & 0x7f; + od = ics307_s_to_od[cw0 & 0x7]; + /* + * CLK1 Freq = Input Frequency * 2 * (VDW + 8) / ((RDW + 2) * OD) + * + * cw0: C1 C0 TTL F1 F0 S2 S1 S0 + * cw1: V8 V7 V6 V5 V4 V3 V2 V1 + * cw2: V0 R6 R5 R4 R3 R2 R1 R0 + * + * R6:R0 = Reference Divider Word (RDW) + * V8:V0 = VCO Divider Word (VDW) + * S2:S0 = Output Divider Select (OD) + * F1:F0 = Function of CLK2 Output + * TTL = duty cycle + * C1:C0 = internal load capacitance for crystal + */ + freq = input_freq * 2 * (vdw + 8) / ((rdw + 2) * od); + + return freq; +} |