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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/mips/pic32/pic32mzda/early_clk.c
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// SPDX-License-Identifier: GPL-2.0-only

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/*

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 * Joshua Henderson <[email protected]>

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 * Copyright (C) 2015 Microchip Technology Inc.  All rights reserved.

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 */

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#include <asm/mach-pic32/pic32.h>

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#include "pic32mzda.h"

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/* Oscillators, PLL & clocks */

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#define ICLK_MASK	0x00000080

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#define PLLDIV_MASK	0x00000007

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#define CUROSC_MASK	0x00000007

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#define PLLMUL_MASK	0x0000007F

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#define PB_MASK		0x00000007

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#define FRC1		0

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#define FRC2		7

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#define SPLL		1

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#define POSC		2

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#define FRC_CLK		8000000

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#define PIC32_POSC_FREQ	24000000

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#define OSCCON		0x0000

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#define SPLLCON		0x0020

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#define PB1DIV		0x0140

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u32 pic32_get_sysclk(void)

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{

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	u32 osc_freq = 0;

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	u32 pllclk;

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	u32 frcdivn;

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	u32 osccon;

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	u32 spllcon;

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	int curr_osc;

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	u32 plliclk;

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	u32 pllidiv;

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	u32 pllodiv;

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	u32 pllmult;

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	u32 frcdiv;

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	void __iomem *osc_base = ioremap(PIC32_BASE_OSC, 0x200);

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	osccon = __raw_readl(osc_base + OSCCON);

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	spllcon = __raw_readl(osc_base + SPLLCON);

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	plliclk = (spllcon & ICLK_MASK);

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	pllidiv = ((spllcon >> 8) & PLLDIV_MASK) + 1;

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	pllodiv = ((spllcon >> 24) & PLLDIV_MASK);

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	pllmult = ((spllcon >> 16) & PLLMUL_MASK) + 1;

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	frcdiv = ((osccon >> 24) & PLLDIV_MASK);

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	pllclk = plliclk ? FRC_CLK : PIC32_POSC_FREQ;

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	frcdivn = ((1 << frcdiv) + 1) + (128 * (frcdiv == 7));

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	if (pllodiv < 2)

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		pllodiv = 2;

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	else if (pllodiv < 5)

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		pllodiv = (1 << pllodiv);

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	else

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		pllodiv = 32;

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	curr_osc = (int)((osccon >> 12) & CUROSC_MASK);

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	switch (curr_osc) {

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	case FRC1:

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	case FRC2:

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		osc_freq = FRC_CLK / frcdivn;

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		break;

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	case SPLL:

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		osc_freq = ((pllclk / pllidiv) * pllmult) / pllodiv;

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		break;

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	case POSC:

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		osc_freq = PIC32_POSC_FREQ;

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		break;

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	default:

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		break;

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	}

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	iounmap(osc_base);

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	return osc_freq;

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}

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u32 pic32_get_pbclk(int bus)

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{

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	u32 clk_freq;

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	void __iomem *osc_base = ioremap(PIC32_BASE_OSC, 0x200);

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	u32 pbxdiv = PB1DIV + ((bus - 1) * 0x10);

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	u32 pbdiv = (__raw_readl(osc_base + pbxdiv) & PB_MASK) + 1;

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	iounmap(osc_base);

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	clk_freq = pic32_get_sysclk();

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	return clk_freq / pbdiv;

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}

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