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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2016 Maxime Ripard
*
* Maxime Ripard <maxime.ripard@free-electrons.com>
*/
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/device.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "ccu_common.h"
#include "ccu_gate.h"
#include "ccu_reset.h"
struct sunxi_ccu {
const struct sunxi_ccu_desc *desc;
spinlock_t lock;
struct ccu_reset reset;
};
void ccu_helper_wait_for_lock(struct ccu_common *common, u32 lock)
{
void __iomem *addr;
u32 reg;
if (!lock)
return;
if (common->features & CCU_FEATURE_LOCK_REG)
addr = common->base + common->lock_reg;
else
addr = common->base + common->reg;
WARN_ON(readl_relaxed_poll_timeout(addr, reg, reg & lock, 100, 70000));
}
EXPORT_SYMBOL_NS_GPL(ccu_helper_wait_for_lock, SUNXI_CCU);
bool ccu_is_better_rate(struct ccu_common *common,
unsigned long target_rate,
unsigned long current_rate,
unsigned long best_rate)
{
if (common->features & CCU_FEATURE_CLOSEST_RATE)
return abs(current_rate - target_rate) < abs(best_rate - target_rate);
return current_rate <= target_rate && current_rate > best_rate;
}
EXPORT_SYMBOL_NS_GPL(ccu_is_better_rate, SUNXI_CCU);
/*
* This clock notifier is called when the frequency of a PLL clock is
* changed. In common PLL designs, changes to the dividers take effect
* almost immediately, while changes to the multipliers (implemented
* as dividers in the feedback loop) take a few cycles to work into
* the feedback loop for the PLL to stablize.
*
* Sometimes when the PLL clock rate is changed, the decrease in the
* divider is too much for the decrease in the multiplier to catch up.
* The PLL clock rate will spike, and in some cases, might lock up
* completely.
*
* This notifier callback will gate and then ungate the clock,
* effectively resetting it, so it proceeds to work. Care must be
* taken to reparent consumers to other temporary clocks during the
* rate change, and that this notifier callback must be the first
* to be registered.
*/
static int ccu_pll_notifier_cb(struct notifier_block *nb,
unsigned long event, void *data)
{
struct ccu_pll_nb *pll = to_ccu_pll_nb(nb);
int ret = 0;
if (event != POST_RATE_CHANGE)
goto out;
ccu_gate_helper_disable(pll->common, pll->enable);
ret = ccu_gate_helper_enable(pll->common, pll->enable);
if (ret)
goto out;
ccu_helper_wait_for_lock(pll->common, pll->lock);
out:
return notifier_from_errno(ret);
}
int ccu_pll_notifier_register(struct ccu_pll_nb *pll_nb)
{
pll_nb->clk_nb.notifier_call = ccu_pll_notifier_cb;
return clk_notifier_register(pll_nb->common->hw.clk,
&pll_nb->clk_nb);
}
EXPORT_SYMBOL_NS_GPL(ccu_pll_notifier_register, SUNXI_CCU);
static int sunxi_ccu_probe(struct sunxi_ccu *ccu, struct device *dev,
struct device_node *node, void __iomem *reg,
const struct sunxi_ccu_desc *desc)
{
struct ccu_reset *reset;
int i, ret;
ccu->desc = desc;
spin_lock_init(&ccu->lock);
for (i = 0; i < desc->num_ccu_clks; i++) {
struct ccu_common *cclk = desc->ccu_clks[i];
if (!cclk)
continue;
cclk->base = reg;
cclk->lock = &ccu->lock;
}
for (i = 0; i < desc->hw_clks->num ; i++) {
struct clk_hw *hw = desc->hw_clks->hws[i];
const char *name;
if (!hw)
continue;
name = hw->init->name;
if (dev)
ret = clk_hw_register(dev, hw);
else
ret = of_clk_hw_register(node, hw);
if (ret) {
pr_err("Couldn't register clock %d - %s\n", i, name);
goto err_clk_unreg;
}
}
ret = of_clk_add_hw_provider(node, of_clk_hw_onecell_get,
desc->hw_clks);
if (ret)
goto err_clk_unreg;
reset = &ccu->reset;
reset->rcdev.of_node = node;
reset->rcdev.ops = &ccu_reset_ops;
reset->rcdev.owner = dev ? dev->driver->owner : THIS_MODULE;
reset->rcdev.nr_resets = desc->num_resets;
reset->base = reg;
reset->lock = &ccu->lock;
reset->reset_map = desc->resets;
ret = reset_controller_register(&reset->rcdev);
if (ret)
goto err_del_provider;
return 0;
err_del_provider:
of_clk_del_provider(node);
err_clk_unreg:
while (--i >= 0) {
struct clk_hw *hw = desc->hw_clks->hws[i];
if (!hw)
continue;
clk_hw_unregister(hw);
}
return ret;
}
static void devm_sunxi_ccu_release(struct device *dev, void *res)
{
struct sunxi_ccu *ccu = res;
const struct sunxi_ccu_desc *desc = ccu->desc;
int i;
reset_controller_unregister(&ccu->reset.rcdev);
of_clk_del_provider(dev->of_node);
for (i = 0; i < desc->hw_clks->num; i++) {
struct clk_hw *hw = desc->hw_clks->hws[i];
if (!hw)
continue;
clk_hw_unregister(hw);
}
}
int devm_sunxi_ccu_probe(struct device *dev, void __iomem *reg,
const struct sunxi_ccu_desc *desc)
{
struct sunxi_ccu *ccu;
int ret;
ccu = devres_alloc(devm_sunxi_ccu_release, sizeof(*ccu), GFP_KERNEL);
if (!ccu)
return -ENOMEM;
ret = sunxi_ccu_probe(ccu, dev, dev->of_node, reg, desc);
if (ret) {
devres_free(ccu);
return ret;
}
devres_add(dev, ccu);
return 0;
}
EXPORT_SYMBOL_NS_GPL(devm_sunxi_ccu_probe, SUNXI_CCU);
void of_sunxi_ccu_probe(struct device_node *node, void __iomem *reg,
const struct sunxi_ccu_desc *desc)
{
struct sunxi_ccu *ccu;
int ret;
ccu = kzalloc(sizeof(*ccu), GFP_KERNEL);
if (!ccu)
return;
ret = sunxi_ccu_probe(ccu, NULL, node, reg, desc);
if (ret) {
pr_err("%pOF: probing clocks failed: %d\n", node, ret);
kfree(ccu);
}
}
MODULE_LICENSE("GPL");
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