xref: /openbmc/linux/drivers/clk/pistachio/clk-pll.c (revision 75bf465f0bc33e9b776a46d6a1b9b990f5fb7c37)

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2014 Google, Inc.
 */

#define pr_fmt(fmt) "%s: " fmt, __func__

#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/slab.h>

#include "clk.h"

#define PLL_STATUS			0x0
#define PLL_STATUS_LOCK			BIT(0)

#define PLL_CTRL1			0x4
#define PLL_CTRL1_REFDIV_SHIFT		0
#define PLL_CTRL1_REFDIV_MASK		0x3f
#define PLL_CTRL1_FBDIV_SHIFT		6
#define PLL_CTRL1_FBDIV_MASK		0xfff
#define PLL_INT_CTRL1_POSTDIV1_SHIFT	18
#define PLL_INT_CTRL1_POSTDIV1_MASK	0x7
#define PLL_INT_CTRL1_POSTDIV2_SHIFT	21
#define PLL_INT_CTRL1_POSTDIV2_MASK	0x7
#define PLL_INT_CTRL1_PD		BIT(24)
#define PLL_INT_CTRL1_DSMPD		BIT(25)
#define PLL_INT_CTRL1_FOUTPOSTDIVPD	BIT(26)
#define PLL_INT_CTRL1_FOUTVCOPD		BIT(27)

#define PLL_CTRL2			0x8
#define PLL_FRAC_CTRL2_FRAC_SHIFT	0
#define PLL_FRAC_CTRL2_FRAC_MASK	0xffffff
#define PLL_FRAC_CTRL2_POSTDIV1_SHIFT	24
#define PLL_FRAC_CTRL2_POSTDIV1_MASK	0x7
#define PLL_FRAC_CTRL2_POSTDIV2_SHIFT	27
#define PLL_FRAC_CTRL2_POSTDIV2_MASK	0x7
#define PLL_INT_CTRL2_BYPASS		BIT(28)

#define PLL_CTRL3			0xc
#define PLL_FRAC_CTRL3_PD		BIT(0)
#define PLL_FRAC_CTRL3_DACPD		BIT(1)
#define PLL_FRAC_CTRL3_DSMPD		BIT(2)
#define PLL_FRAC_CTRL3_FOUTPOSTDIVPD	BIT(3)
#define PLL_FRAC_CTRL3_FOUT4PHASEPD	BIT(4)
#define PLL_FRAC_CTRL3_FOUTVCOPD	BIT(5)

#define PLL_CTRL4			0x10
#define PLL_FRAC_CTRL4_BYPASS		BIT(28)

#define MIN_PFD				9600000UL
#define MIN_VCO_LA			400000000UL
#define MAX_VCO_LA			1600000000UL
#define MIN_VCO_FRAC_INT		600000000UL
#define MAX_VCO_FRAC_INT		1600000000UL
#define MIN_VCO_FRAC_FRAC		600000000UL
#define MAX_VCO_FRAC_FRAC		2400000000UL
#define MIN_OUTPUT_LA			8000000UL
#define MAX_OUTPUT_LA			1600000000UL
#define MIN_OUTPUT_FRAC			12000000UL
#define MAX_OUTPUT_FRAC			1600000000UL

/* Fractional PLL operating modes */
enum pll_mode {
	PLL_MODE_FRAC,
	PLL_MODE_INT,
};

struct pistachio_clk_pll {
	struct clk_hw hw;
	void __iomem *base;
	struct pistachio_pll_rate_table *rates;
	unsigned int nr_rates;
};

static inline u32 pll_readl(struct pistachio_clk_pll *pll, u32 reg)
{
	return readl(pll->base + reg);
}

static inline void pll_writel(struct pistachio_clk_pll *pll, u32 val, u32 reg)
{
	writel(val, pll->base + reg);
}

static inline void pll_lock(struct pistachio_clk_pll *pll)
{
	while (!(pll_readl(pll, PLL_STATUS) & PLL_STATUS_LOCK))
		cpu_relax();
}

static inline u64 do_div_round_closest(u64 dividend, u64 divisor)
{
	dividend += divisor / 2;
	return div64_u64(dividend, divisor);
}

static inline struct pistachio_clk_pll *to_pistachio_pll(struct clk_hw *hw)
{
	return container_of(hw, struct pistachio_clk_pll, hw);
}

static inline enum pll_mode pll_frac_get_mode(struct clk_hw *hw)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
	u32 val;

	val = pll_readl(pll, PLL_CTRL3) & PLL_FRAC_CTRL3_DSMPD;
	return val ? PLL_MODE_INT : PLL_MODE_FRAC;
}

static inline void pll_frac_set_mode(struct clk_hw *hw, enum pll_mode mode)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
	u32 val;

	val = pll_readl(pll, PLL_CTRL3);
	if (mode == PLL_MODE_INT)
		val |= PLL_FRAC_CTRL3_DSMPD | PLL_FRAC_CTRL3_DACPD;
	else
		val &= ~(PLL_FRAC_CTRL3_DSMPD | PLL_FRAC_CTRL3_DACPD);

	pll_writel(pll, val, PLL_CTRL3);
}

static struct pistachio_pll_rate_table *
pll_get_params(struct pistachio_clk_pll *pll, unsigned long fref,
	       unsigned long fout)
{
	unsigned int i;

	for (i = 0; i < pll->nr_rates; i++) {
		if (pll->rates[i].fref == fref && pll->rates[i].fout == fout)
			return &pll->rates[i];
	}

	return NULL;
}

static long pll_round_rate(struct clk_hw *hw, unsigned long rate,
			   unsigned long *parent_rate)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
	unsigned int i;

	for (i = 0; i < pll->nr_rates; i++) {
		if (i > 0 && pll->rates[i].fref == *parent_rate &&
		    pll->rates[i].fout <= rate)
			return pll->rates[i - 1].fout;
	}

	return pll->rates[0].fout;
}

static int pll_gf40lp_frac_enable(struct clk_hw *hw)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
	u32 val;

	val = pll_readl(pll, PLL_CTRL3);
	val &= ~(PLL_FRAC_CTRL3_PD | PLL_FRAC_CTRL3_FOUTPOSTDIVPD |
		 PLL_FRAC_CTRL3_FOUT4PHASEPD | PLL_FRAC_CTRL3_FOUTVCOPD);
	pll_writel(pll, val, PLL_CTRL3);

	val = pll_readl(pll, PLL_CTRL4);
	val &= ~PLL_FRAC_CTRL4_BYPASS;
	pll_writel(pll, val, PLL_CTRL4);

	pll_lock(pll);

	return 0;
}

static void pll_gf40lp_frac_disable(struct clk_hw *hw)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
	u32 val;

	val = pll_readl(pll, PLL_CTRL3);
	val |= PLL_FRAC_CTRL3_PD;
	pll_writel(pll, val, PLL_CTRL3);
}

static int pll_gf40lp_frac_is_enabled(struct clk_hw *hw)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);

	return !(pll_readl(pll, PLL_CTRL3) & PLL_FRAC_CTRL3_PD);
}

static int pll_gf40lp_frac_set_rate(struct clk_hw *hw, unsigned long rate,
				    unsigned long parent_rate)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
	struct pistachio_pll_rate_table *params;
	int enabled = pll_gf40lp_frac_is_enabled(hw);
	u64 val, vco, old_postdiv1, old_postdiv2;
	const char *name = clk_hw_get_name(hw);

	if (rate < MIN_OUTPUT_FRAC || rate > MAX_OUTPUT_FRAC)
		return -EINVAL;

	params = pll_get_params(pll, parent_rate, rate);
	if (!params || !params->refdiv)
		return -EINVAL;

	/* calculate vco */
	vco = params->fref;
	vco *= (params->fbdiv << 24) + params->frac;
	vco = div64_u64(vco, params->refdiv << 24);

	if (vco < MIN_VCO_FRAC_FRAC || vco > MAX_VCO_FRAC_FRAC)
		pr_warn("%s: VCO %llu is out of range %lu..%lu\n", name, vco,
			MIN_VCO_FRAC_FRAC, MAX_VCO_FRAC_FRAC);

	val = div64_u64(params->fref, params->refdiv);
	if (val < MIN_PFD)
		pr_warn("%s: PFD %llu is too low (min %lu)\n",
			name, val, MIN_PFD);
	if (val > vco / 16)
		pr_warn("%s: PFD %llu is too high (max %llu)\n",
			name, val, vco / 16);

	val = pll_readl(pll, PLL_CTRL1);
	val &= ~((PLL_CTRL1_REFDIV_MASK << PLL_CTRL1_REFDIV_SHIFT) |
		 (PLL_CTRL1_FBDIV_MASK << PLL_CTRL1_FBDIV_SHIFT));
	val |= (params->refdiv << PLL_CTRL1_REFDIV_SHIFT) |
		(params->fbdiv << PLL_CTRL1_FBDIV_SHIFT);
	pll_writel(pll, val, PLL_CTRL1);

	val = pll_readl(pll, PLL_CTRL2);

	old_postdiv1 = (val >> PLL_FRAC_CTRL2_POSTDIV1_SHIFT) &
		       PLL_FRAC_CTRL2_POSTDIV1_MASK;
	old_postdiv2 = (val >> PLL_FRAC_CTRL2_POSTDIV2_SHIFT) &
		       PLL_FRAC_CTRL2_POSTDIV2_MASK;
	if (enabled &&
	    (params->postdiv1 != old_postdiv1 ||
	     params->postdiv2 != old_postdiv2))
		pr_warn("%s: changing postdiv while PLL is enabled\n", name);

	if (params->postdiv2 > params->postdiv1)
		pr_warn("%s: postdiv2 should not exceed postdiv1\n", name);

	val &= ~((PLL_FRAC_CTRL2_FRAC_MASK << PLL_FRAC_CTRL2_FRAC_SHIFT) |
		 (PLL_FRAC_CTRL2_POSTDIV1_MASK <<
		  PLL_FRAC_CTRL2_POSTDIV1_SHIFT) |
		 (PLL_FRAC_CTRL2_POSTDIV2_MASK <<
		  PLL_FRAC_CTRL2_POSTDIV2_SHIFT));
	val |= (params->frac << PLL_FRAC_CTRL2_FRAC_SHIFT) |
		(params->postdiv1 << PLL_FRAC_CTRL2_POSTDIV1_SHIFT) |
		(params->postdiv2 << PLL_FRAC_CTRL2_POSTDIV2_SHIFT);
	pll_writel(pll, val, PLL_CTRL2);

	/* set operating mode */
	if (params->frac)
		pll_frac_set_mode(hw, PLL_MODE_FRAC);
	else
		pll_frac_set_mode(hw, PLL_MODE_INT);

	if (enabled)
		pll_lock(pll);

	return 0;
}

static unsigned long pll_gf40lp_frac_recalc_rate(struct clk_hw *hw,
						 unsigned long parent_rate)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
	u64 val, prediv, fbdiv, frac, postdiv1, postdiv2, rate;

	val = pll_readl(pll, PLL_CTRL1);
	prediv = (val >> PLL_CTRL1_REFDIV_SHIFT) & PLL_CTRL1_REFDIV_MASK;
	fbdiv = (val >> PLL_CTRL1_FBDIV_SHIFT) & PLL_CTRL1_FBDIV_MASK;

	val = pll_readl(pll, PLL_CTRL2);
	postdiv1 = (val >> PLL_FRAC_CTRL2_POSTDIV1_SHIFT) &
		PLL_FRAC_CTRL2_POSTDIV1_MASK;
	postdiv2 = (val >> PLL_FRAC_CTRL2_POSTDIV2_SHIFT) &
		PLL_FRAC_CTRL2_POSTDIV2_MASK;
	frac = (val >> PLL_FRAC_CTRL2_FRAC_SHIFT) & PLL_FRAC_CTRL2_FRAC_MASK;

	/* get operating mode (int/frac) and calculate rate accordingly */
	rate = parent_rate;
	if (pll_frac_get_mode(hw) == PLL_MODE_FRAC)
		rate *= (fbdiv << 24) + frac;
	else
		rate *= (fbdiv << 24);

	rate = do_div_round_closest(rate, (prediv * postdiv1 * postdiv2) << 24);

	return rate;
}

static const struct clk_ops pll_gf40lp_frac_ops = {
	.enable = pll_gf40lp_frac_enable,
	.disable = pll_gf40lp_frac_disable,
	.is_enabled = pll_gf40lp_frac_is_enabled,
	.recalc_rate = pll_gf40lp_frac_recalc_rate,
	.round_rate = pll_round_rate,
	.set_rate = pll_gf40lp_frac_set_rate,
};

static const struct clk_ops pll_gf40lp_frac_fixed_ops = {
	.enable = pll_gf40lp_frac_enable,
	.disable = pll_gf40lp_frac_disable,
	.is_enabled = pll_gf40lp_frac_is_enabled,
	.recalc_rate = pll_gf40lp_frac_recalc_rate,
};

static int pll_gf40lp_laint_enable(struct clk_hw *hw)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
	u32 val;

	val = pll_readl(pll, PLL_CTRL1);
	val &= ~(PLL_INT_CTRL1_PD |
		 PLL_INT_CTRL1_FOUTPOSTDIVPD | PLL_INT_CTRL1_FOUTVCOPD);
	pll_writel(pll, val, PLL_CTRL1);

	val = pll_readl(pll, PLL_CTRL2);
	val &= ~PLL_INT_CTRL2_BYPASS;
	pll_writel(pll, val, PLL_CTRL2);

	pll_lock(pll);

	return 0;
}

static void pll_gf40lp_laint_disable(struct clk_hw *hw)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
	u32 val;

	val = pll_readl(pll, PLL_CTRL1);
	val |= PLL_INT_CTRL1_PD;
	pll_writel(pll, val, PLL_CTRL1);
}

static int pll_gf40lp_laint_is_enabled(struct clk_hw *hw)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);

	return !(pll_readl(pll, PLL_CTRL1) & PLL_INT_CTRL1_PD);
}

static int pll_gf40lp_laint_set_rate(struct clk_hw *hw, unsigned long rate,
				     unsigned long parent_rate)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
	struct pistachio_pll_rate_table *params;
	int enabled = pll_gf40lp_laint_is_enabled(hw);
	u32 val, vco, old_postdiv1, old_postdiv2;
	const char *name = clk_hw_get_name(hw);

	if (rate < MIN_OUTPUT_LA || rate > MAX_OUTPUT_LA)
		return -EINVAL;

	params = pll_get_params(pll, parent_rate, rate);
	if (!params || !params->refdiv)
		return -EINVAL;

	vco = div_u64(params->fref * params->fbdiv, params->refdiv);
	if (vco < MIN_VCO_LA || vco > MAX_VCO_LA)
		pr_warn("%s: VCO %u is out of range %lu..%lu\n", name, vco,
			MIN_VCO_LA, MAX_VCO_LA);

	val = div_u64(params->fref, params->refdiv);
	if (val < MIN_PFD)
		pr_warn("%s: PFD %u is too low (min %lu)\n",
			name, val, MIN_PFD);
	if (val > vco / 16)
		pr_warn("%s: PFD %u is too high (max %u)\n",
			name, val, vco / 16);

	val = pll_readl(pll, PLL_CTRL1);

	old_postdiv1 = (val >> PLL_INT_CTRL1_POSTDIV1_SHIFT) &
		       PLL_INT_CTRL1_POSTDIV1_MASK;
	old_postdiv2 = (val >> PLL_INT_CTRL1_POSTDIV2_SHIFT) &
		       PLL_INT_CTRL1_POSTDIV2_MASK;
	if (enabled &&
	    (params->postdiv1 != old_postdiv1 ||
	     params->postdiv2 != old_postdiv2))
		pr_warn("%s: changing postdiv while PLL is enabled\n", name);

	if (params->postdiv2 > params->postdiv1)
		pr_warn("%s: postdiv2 should not exceed postdiv1\n", name);

	val &= ~((PLL_CTRL1_REFDIV_MASK << PLL_CTRL1_REFDIV_SHIFT) |
		 (PLL_CTRL1_FBDIV_MASK << PLL_CTRL1_FBDIV_SHIFT) |
		 (PLL_INT_CTRL1_POSTDIV1_MASK << PLL_INT_CTRL1_POSTDIV1_SHIFT) |
		 (PLL_INT_CTRL1_POSTDIV2_MASK << PLL_INT_CTRL1_POSTDIV2_SHIFT));
	val |= (params->refdiv << PLL_CTRL1_REFDIV_SHIFT) |
		(params->fbdiv << PLL_CTRL1_FBDIV_SHIFT) |
		(params->postdiv1 << PLL_INT_CTRL1_POSTDIV1_SHIFT) |
		(params->postdiv2 << PLL_INT_CTRL1_POSTDIV2_SHIFT);
	pll_writel(pll, val, PLL_CTRL1);

	if (enabled)
		pll_lock(pll);

	return 0;
}

static unsigned long pll_gf40lp_laint_recalc_rate(struct clk_hw *hw,
						  unsigned long parent_rate)
{
	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
	u32 val, prediv, fbdiv, postdiv1, postdiv2;
	u64 rate = parent_rate;

	val = pll_readl(pll, PLL_CTRL1);
	prediv = (val >> PLL_CTRL1_REFDIV_SHIFT) & PLL_CTRL1_REFDIV_MASK;
	fbdiv = (val >> PLL_CTRL1_FBDIV_SHIFT) & PLL_CTRL1_FBDIV_MASK;
	postdiv1 = (val >> PLL_INT_CTRL1_POSTDIV1_SHIFT) &
		PLL_INT_CTRL1_POSTDIV1_MASK;
	postdiv2 = (val >> PLL_INT_CTRL1_POSTDIV2_SHIFT) &
		PLL_INT_CTRL1_POSTDIV2_MASK;

	rate *= fbdiv;
	rate = do_div_round_closest(rate, prediv * postdiv1 * postdiv2);

	return rate;
}

static const struct clk_ops pll_gf40lp_laint_ops = {
	.enable = pll_gf40lp_laint_enable,
	.disable = pll_gf40lp_laint_disable,
	.is_enabled = pll_gf40lp_laint_is_enabled,
	.recalc_rate = pll_gf40lp_laint_recalc_rate,
	.round_rate = pll_round_rate,
	.set_rate = pll_gf40lp_laint_set_rate,
};

static const struct clk_ops pll_gf40lp_laint_fixed_ops = {
	.enable = pll_gf40lp_laint_enable,
	.disable = pll_gf40lp_laint_disable,
	.is_enabled = pll_gf40lp_laint_is_enabled,
	.recalc_rate = pll_gf40lp_laint_recalc_rate,
};

static struct clk *pll_register(const char *name, const char *parent_name,
				unsigned long flags, void __iomem *base,
				enum pistachio_pll_type type,
				struct pistachio_pll_rate_table *rates,
				unsigned int nr_rates)
{
	struct pistachio_clk_pll *pll;
	struct clk_init_data init;
	struct clk *clk;

	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
	if (!pll)
		return ERR_PTR(-ENOMEM);

	init.name = name;
	init.flags = flags | CLK_GET_RATE_NOCACHE;
	init.parent_names = &parent_name;
	init.num_parents = 1;

	switch (type) {
	case PLL_GF40LP_FRAC:
		if (rates)
			init.ops = &pll_gf40lp_frac_ops;
		else
			init.ops = &pll_gf40lp_frac_fixed_ops;
		break;
	case PLL_GF40LP_LAINT:
		if (rates)
			init.ops = &pll_gf40lp_laint_ops;
		else
			init.ops = &pll_gf40lp_laint_fixed_ops;
		break;
	default:
		pr_err("Unrecognized PLL type %u\n", type);
		kfree(pll);
		return ERR_PTR(-EINVAL);
	}

	pll->hw.init = &init;
	pll->base = base;
	pll->rates = rates;
	pll->nr_rates = nr_rates;

	clk = clk_register(NULL, &pll->hw);
	if (IS_ERR(clk))
		kfree(pll);

	return clk;
}

void pistachio_clk_register_pll(struct pistachio_clk_provider *p,
				struct pistachio_pll *pll,
				unsigned int num)
{
	struct clk *clk;
	unsigned int i;

	for (i = 0; i < num; i++) {
		clk = pll_register(pll[i].name, pll[i].parent,
				   0, p->base + pll[i].reg_base,
				   pll[i].type, pll[i].rates,
				   pll[i].nr_rates);
		p->clk_data.clks[pll[i].id] = clk;
	}
}