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