clk-generated.c
/*
* 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/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 PERIPHERAL_MAX 64
#define PERIPHERAL_ID_MIN 2
#define GENERATED_SOURCE_MAX 6
#define GENERATED_MAX_DIV 255
struct clk_generated {
struct clk_hw hw;
struct regmap *regmap;
struct clk_range range;
spinlock_t *lock;
u32 id;
u32 gckdiv;
u8 parent_id;
};
#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, AT91_PMC_PCR,
(gck->id & AT91_PMC_PCR_PID_MASK));
regmap_update_bits(gck->regmap, AT91_PMC_PCR,
AT91_PMC_PCR_GCKDIV_MASK | AT91_PMC_PCR_GCKCSS_MASK |
AT91_PMC_PCR_CMD | AT91_PMC_PCR_GCKEN,
AT91_PMC_PCR_GCKCSS(gck->parent_id) |
AT91_PMC_PCR_CMD |
AT91_PMC_PCR_GCKDIV(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, AT91_PMC_PCR,
(gck->id & AT91_PMC_PCR_PID_MASK));
regmap_update_bits(gck->regmap, AT91_PMC_PCR,
AT91_PMC_PCR_CMD | AT91_PMC_PCR_GCKEN,
AT91_PMC_PCR_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, AT91_PMC_PCR,
(gck->id & AT91_PMC_PCR_PID_MASK));
regmap_read(gck->regmap, AT91_PMC_PCR, &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 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;
long best_rate = -EINVAL;
unsigned long tmp_rate, min_rate;
int best_diff = -1;
int tmp_diff;
int i;
for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
u32 div;
unsigned long parent_rate;
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;
for (div = 1; div < GENERATED_MAX_DIV + 2; div++) {
tmp_rate = DIV_ROUND_CLOSEST(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;
}
if (!best_diff || tmp_rate < req->rate)
break;
}
if (!best_diff)
break;
}
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, AT91_PMC_PCR,
(gck->id & AT91_PMC_PCR_PID_MASK));
regmap_read(gck->regmap, AT91_PMC_PCR, &tmp);
spin_unlock_irqrestore(gck->lock, flags);
gck->parent_id = (tmp & AT91_PMC_PCR_GCKCSS_MASK)
>> AT91_PMC_PCR_GCKCSS_OFFSET;
gck->gckdiv = (tmp & AT91_PMC_PCR_GCKDIV_MASK)
>> AT91_PMC_PCR_GCKDIV_OFFSET;
}
static struct clk_hw * __init
at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock,
const char *name, const char **parent_names,
u8 num_parents, u8 id,
const struct clk_range *range)
{
struct clk_generated *gck;
struct clk_init_data init;
struct clk_hw *hw;
int ret;
gck = kzalloc(sizeof(*gck), GFP_KERNEL);
if (!gck)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &generated_ops;
init.parent_names = parent_names;
init.num_parents = num_parents;
init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
gck->id = id;
gck->hw.init = &init;
gck->regmap = regmap;
gck->lock = lock;
gck->range = *range;
hw = &gck->hw;
ret = clk_hw_register(NULL, &gck->hw);
if (ret) {
kfree(gck);
hw = ERR_PTR(ret);
} else
clk_generated_startup(gck);
return hw;
}
static void __init of_sama5d2_clk_generated_setup(struct device_node *np)
{
int num;
u32 id;
const char *name;
struct clk_hw *hw;
unsigned int num_parents;
const char *parent_names[GENERATED_SOURCE_MAX];
struct device_node *gcknp;
struct clk_range range = CLK_RANGE(0, 0);
struct regmap *regmap;
num_parents = of_clk_get_parent_count(np);
if (num_parents == 0 || num_parents > GENERATED_SOURCE_MAX)
return;
of_clk_parent_fill(np, parent_names, num_parents);
num = of_get_child_count(np);
if (!num || num > PERIPHERAL_MAX)
return;
regmap = syscon_node_to_regmap(of_get_parent(np));
if (IS_ERR(regmap))
return;
for_each_child_of_node(np, gcknp) {
if (of_property_read_u32(gcknp, "reg", &id))
continue;
if (id < PERIPHERAL_ID_MIN || id >= PERIPHERAL_MAX)
continue;
if (of_property_read_string(np, "clock-output-names", &name))
name = gcknp->name;
of_at91_get_clk_range(gcknp, "atmel,clk-output-range",
&range);
hw = at91_clk_register_generated(regmap, &pmc_pcr_lock, name,
parent_names, num_parents,
id, &range);
if (IS_ERR(hw))
continue;
of_clk_add_hw_provider(gcknp, of_clk_hw_simple_get, hw);
}
}
CLK_OF_DECLARE(of_sama5d2_clk_generated_setup, "atmel,sama5d2-clk-generated",
of_sama5d2_clk_generated_setup);