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/*
* Copyright (C) 2015 Atmel Corporation,
* Nicolas Ferre <nicolas.ferre@atmel.com>
*
* Based on clk-programmable & clk-peripheral drivers by Boris BREZILLON.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
*/
#include <linux/bitfield.h>
#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/clk/at91_pmc.h>
#include <linux/of.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include "pmc.h"
#define GENERATED_MAX_DIV 255
#define GCK_INDEX_DT_AUDIO_PLL 5
struct clk_generated {
struct clk_hw hw;
struct regmap *regmap;
struct clk_range range;
spinlock_t *lock;
u32 id;
u32 gckdiv;
const struct clk_pcr_layout *layout;
u8 parent_id;
bool audio_pll_allowed;
};
#define to_clk_generated(hw) \
container_of(hw, struct clk_generated, hw)
static int clk_generated_enable(struct clk_hw *hw)
{
struct clk_generated *gck = to_clk_generated(hw);
unsigned long flags;
pr_debug("GCLK: %s, gckdiv = %d, parent id = %d\n",
__func__, gck->gckdiv, gck->parent_id);
spin_lock_irqsave(gck->lock, flags);
regmap_write(gck->regmap, gck->layout->offset,
(gck->id & gck->layout->pid_mask));
regmap_update_bits(gck->regmap, gck->layout->offset,
AT91_PMC_PCR_GCKDIV_MASK | gck->layout->gckcss_mask |
gck->layout->cmd | AT91_PMC_PCR_GCKEN,
field_prep(gck->layout->gckcss_mask, gck->parent_id) |
gck->layout->cmd |
FIELD_PREP(AT91_PMC_PCR_GCKDIV_MASK, gck->gckdiv) |
AT91_PMC_PCR_GCKEN);
spin_unlock_irqrestore(gck->lock, flags);
return 0;
}
static void clk_generated_disable(struct clk_hw *hw)
{
struct clk_generated *gck = to_clk_generated(hw);
unsigned long flags;
spin_lock_irqsave(gck->lock, flags);
regmap_write(gck->regmap, gck->layout->offset,
(gck->id & gck->layout->pid_mask));
regmap_update_bits(gck->regmap, gck->layout->offset,
gck->layout->cmd | AT91_PMC_PCR_GCKEN,
gck->layout->cmd);
spin_unlock_irqrestore(gck->lock, flags);
}
static int clk_generated_is_enabled(struct clk_hw *hw)
{
struct clk_generated *gck = to_clk_generated(hw);
unsigned long flags;
unsigned int status;
spin_lock_irqsave(gck->lock, flags);
regmap_write(gck->regmap, gck->layout->offset,
(gck->id & gck->layout->pid_mask));
regmap_read(gck->regmap, gck->layout->offset, &status);
spin_unlock_irqrestore(gck->lock, flags);
return status & AT91_PMC_PCR_GCKEN ? 1 : 0;
}
static unsigned long
clk_generated_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_generated *gck = to_clk_generated(hw);
return DIV_ROUND_CLOSEST(parent_rate, gck->gckdiv + 1);
}
static void clk_generated_best_diff(struct clk_rate_request *req,
struct clk_hw *parent,
unsigned long parent_rate, u32 div,
int *best_diff, long *best_rate)
{
unsigned long tmp_rate;
int tmp_diff;
if (!div)
tmp_rate = parent_rate;
else
tmp_rate = parent_rate / div;
tmp_diff = abs(req->rate - tmp_rate);
if (*best_diff < 0 || *best_diff > tmp_diff) {
*best_rate = tmp_rate;
*best_diff = tmp_diff;
req->best_parent_rate = parent_rate;
req->best_parent_hw = parent;
}
}
static int clk_generated_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct clk_generated *gck = to_clk_generated(hw);
struct clk_hw *parent = NULL;
struct clk_rate_request req_parent = *req;
long best_rate = -EINVAL;
unsigned long min_rate, parent_rate;
int best_diff = -1;
int i;
u32 div;
for (i = 0; i < clk_hw_get_num_parents(hw) - 1; i++) {
parent = clk_hw_get_parent_by_index(hw, i);
if (!parent)
continue;
parent_rate = clk_hw_get_rate(parent);
min_rate = DIV_ROUND_CLOSEST(parent_rate, GENERATED_MAX_DIV + 1);
if (!parent_rate ||
(gck->range.max && min_rate > gck->range.max))
continue;
div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
clk_generated_best_diff(req, parent, parent_rate, div,
&best_diff, &best_rate);
if (!best_diff)
break;
}
/*
* The audio_pll rate can be modified, unlike the five others clocks
* that should never be altered.
* The audio_pll can technically be used by multiple consumers. However,
* with the rate locking, the first consumer to enable to clock will be
* the one definitely setting the rate of the clock.
* Since audio IPs are most likely to request the same rate, we enforce
* that the only clks able to modify gck rate are those of audio IPs.
*/
if (!gck->audio_pll_allowed)
goto end;
parent = clk_hw_get_parent_by_index(hw, GCK_INDEX_DT_AUDIO_PLL);
if (!parent)
goto end;
for (div = 1; div < GENERATED_MAX_DIV + 2; div++) {
req_parent.rate = req->rate * div;
__clk_determine_rate(parent, &req_parent);
clk_generated_best_diff(req, parent, req_parent.rate, div,
&best_diff, &best_rate);
if (!best_diff)
break;
}
end:
pr_debug("GCLK: %s, best_rate = %ld, parent clk: %s @ %ld\n",
__func__, best_rate,
__clk_get_name((req->best_parent_hw)->clk),
req->best_parent_rate);
if (best_rate < 0)
return best_rate;
req->rate = best_rate;
return 0;
}
/* No modification of hardware as we have the flag CLK_SET_PARENT_GATE set */
static int clk_generated_set_parent(struct clk_hw *hw, u8 index)
{
struct clk_generated *gck = to_clk_generated(hw);
if (index >= clk_hw_get_num_parents(hw))
return -EINVAL;
gck->parent_id = index;
return 0;
}
static u8 clk_generated_get_parent(struct clk_hw *hw)
{
struct clk_generated *gck = to_clk_generated(hw);
return gck->parent_id;
}
/* No modification of hardware as we have the flag CLK_SET_RATE_GATE set */
static int clk_generated_set_rate(struct clk_hw *hw,
unsigned long rate,
unsigned long parent_rate)
{
struct clk_generated *gck = to_clk_generated(hw);
u32 div;
if (!rate)
return -EINVAL;
if (gck->range.max && rate > gck->range.max)
return -EINVAL;
div = DIV_ROUND_CLOSEST(parent_rate, rate);
if (div > GENERATED_MAX_DIV + 1 || !div)
return -EINVAL;
gck->gckdiv = div - 1;
return 0;
}
static const struct clk_ops generated_ops = {
.enable = clk_generated_enable,
.disable = clk_generated_disable,
.is_enabled = clk_generated_is_enabled,
.recalc_rate = clk_generated_recalc_rate,
.determine_rate = clk_generated_determine_rate,
.get_parent = clk_generated_get_parent,
.set_parent = clk_generated_set_parent,
.set_rate = clk_generated_set_rate,
};
/**
* clk_generated_startup - Initialize a given clock to its default parent and
* divisor parameter.
*
* @gck: Generated clock to set the startup parameters for.
*
* Take parameters from the hardware and update local clock configuration
* accordingly.
*/
static void clk_generated_startup(struct clk_generated *gck)
{
u32 tmp;
unsigned long flags;
spin_lock_irqsave(gck->lock, flags);
regmap_write(gck->regmap, gck->layout->offset,
(gck->id & gck->layout->pid_mask));
regmap_read(gck->regmap, gck->layout->offset, &tmp);
spin_unlock_irqrestore(gck->lock, flags);
gck->parent_id = field_get(gck->layout->gckcss_mask, tmp);
gck->gckdiv = FIELD_GET(AT91_PMC_PCR_GCKDIV_MASK, tmp);
}
struct clk_hw * __init
at91_clk_register_generated(struct
|