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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2018 NXP.
*
* This driver supports the fractional plls found in the imx8m SOCs
*
* Documentation for this fractional pll can be found at:
* https://www.nxp.com/docs/en/reference-manual/IMX8MDQLQRM.pdf#page=834
*/
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/iopoll.h>
#include <linux/slab.h>
#include <linux/bitfield.h>
#include "clk.h"
#define PLL_CFG0 0x0
#define PLL_CFG1 0x4
#define PLL_LOCK_STATUS BIT(31)
#define PLL_PD_MASK BIT(19)
#define PLL_BYPASS_MASK BIT(14)
#define PLL_NEWDIV_VAL BIT(12)
#define PLL_NEWDIV_ACK BIT(11)
#define PLL_FRAC_DIV_MASK GENMASK(30, 7)
#define PLL_INT_DIV_MASK GENMASK(6, 0)
#define PLL_OUTPUT_DIV_MASK GENMASK(4, 0)
#define PLL_FRAC_DENOM 0x1000000
#define PLL_FRAC_LOCK_TIMEOUT 10000
#define PLL_FRAC_ACK_TIMEOUT 500000
struct clk_frac_pll {
struct clk_hw hw;
void __iomem *base;
};
#define to_clk_frac_pll(_hw) container_of(_hw, struct clk_frac_pll, hw)
static int clk_wait_lock(struct clk_frac_pll *pll)
{
u32 val;
return readl_poll_timeout(pll->base, val, val & PLL_LOCK_STATUS, 0,
PLL_FRAC_LOCK_TIMEOUT);
}
static int clk_wait_ack(struct clk_frac_pll *pll)
{
u32 val;
/* return directly if the pll is in powerdown or in bypass */
if (readl_relaxed(pll->base) & (PLL_PD_MASK | PLL_BYPASS_MASK))
return 0;
/* Wait for the pll's divfi and divff to be reloaded */
return readl_poll_timeout(pll->base, val, val & PLL_NEWDIV_ACK, 0,
PLL_FRAC_ACK_TIMEOUT);
}
static int clk_pll_prepare(struct clk_hw *hw)
{
struct clk_frac_pll *pll = to_clk_frac_pll(hw);
u32 val;
val = readl_relaxed(pll->base + PLL_CFG0);
val &= ~PLL_PD_MASK;
writel_relaxed(val, pll->base + PLL_CFG0);
return clk_wait_lock(pll);
}
static void clk_pll_unprepare(struct clk_hw *hw)
{
struct clk_frac_pll *pll = to_clk_frac_pll(hw);
u32 val;
val = readl_relaxed(pll->base + PLL_CFG0);
val |= PLL_PD_MASK;
writel_relaxed(val, pll->base + PLL_CFG0);
}
static int clk_pll_is_prepared(struct clk_hw *hw)
{
struct clk_frac_pll *pll = to_clk_frac_pll(hw);
u32 val;
val = readl_relaxed(pll->base + PLL_CFG0);
return (val & PLL_PD_MASK) ? 0 : 1;
}
static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_frac_pll *pll = to_clk_frac_pll(hw);
u32 val, divff, divfi, divq;
u64 temp64 = parent_rate;
u64 rate;
val = readl_relaxed(pll->base + PLL_CFG0);
divq = (FIELD_GET(PLL_OUTPUT_DIV_MASK, val) + 1) * 2;
val = readl_relaxed(pll->base + PLL_CFG1);
divff = FIELD_GET(PLL_FRAC_DIV_MASK, val);
divfi = FIELD_GET(PLL_INT_DIV_MASK, val);
temp64 *= 8;
temp64 *= divff;
do_div(temp64, PLL_FRAC_DENOM);
do_div(temp64, divq);
rate = parent_rate * 8 * (divfi + 1);
do_div(rate, divq);
rate += temp64;
return rate;
}
static long clk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
u64 parent_rate = *prate;
u32 divff, divfi;
u64 temp64;
parent_rate *= 8;
rate *= 2;
temp64 = rate;
do_div(temp64, parent_rate);
divfi = temp64;
temp64 = rate - divfi * parent_rate;
temp64 *= PLL_FRAC_DENOM;
do_div(temp64, parent_rate);
divff = temp64;
temp64 = parent_rate;
temp64 *= divff;
do_div(temp64, PLL_FRAC_DENOM);
rate = parent_rate * divfi + temp64;
return rate / 2;
}
/*
* To simplify the clock calculation, we can keep the 'PLL_OUTPUT_VAL' at zero
* (means the PLL output will be divided by 2). So the PLL output can use
* the below formula:
* pllout = parent_rate * 8 / 2 * DIVF_VAL;
* where DIVF_VAL = 1 + DIVFI + DIVFF / 2^24.
*/
static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_frac_pll *pll = to_clk_frac_pll(hw);
u32 val, divfi, divff;
u64 temp64;
int ret;
parent_rate *= 8;
rate *= 2;
divfi = rate / parent_rate;
temp64 = parent_rate * divfi;
temp64 = rate - temp64;
temp64 *= PLL_FRAC_DENOM;
do_div(temp64, parent_rate);
divff = temp64;
val = readl_relaxed(pll->base + PLL_CFG1);
val &= ~(PLL_FRAC_DIV_MASK | PLL_INT_DIV_MASK);
val |= (divff << 7) | (divfi - 1);
writel_relaxed(val, pll->base + PLL_CFG1);
val = readl_relaxed(pll->base + PLL_CFG0);
val &= ~0x1f;
writel_relaxed(val, pll->base + PLL_CFG0);
/* Set the NEV_DIV_VAL to reload the DIVFI and DIVFF */
val = readl_relaxed(pll->base + PLL_CFG0);
val |= PLL_NEWDIV_VAL;
writel_relaxed(val, pll->base + PLL_CFG0);
ret = clk_wait_ack(pll);
/* clear the NEV_DIV_VAL */
val = readl_relaxed(pll->base + PLL_CFG0);
val &= ~PLL_NEWDIV_VAL;
writel_relaxed(val, pll->base + PLL_CFG0);
return ret;
}
static const struct clk_ops clk_frac_pll_ops = {
.prepare = clk_pll_prepare,
.unprepare = clk_pll_unprepare,
.is_prepared = clk_pll_is_prepared,
.recalc_rate = clk_pll_recalc_rate,
.round_rate = clk_pll_round_rate,
.set_rate = clk_pll_set_rate,
};
struct clk *imx_clk_frac_pll(const char *name, const char *parent_name,
void __iomem *base)
{
struct clk_init_data init;
struct clk_frac_pll *pll;
struct clk_hw *hw;
int ret;
pll = kzalloc(sizeof(*pll), GFP_KERNEL);
if (!pll)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &clk_frac_pll_ops;
init.flags = 0;
init.parent_names = &parent_name;
init.num_parents = 1;
pll->base = base;
pll->hw.init = &init;
hw = &pll->hw;
ret = clk_hw_register(NULL, hw);
if (ret) {
kfree(pll);
return ERR_PTR(ret);
}
return hw->clk;
}
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