diff options
Diffstat (limited to 'drivers/clk/sunxi-ng/ccu_common.c')
| -rw-r--r-- | drivers/clk/sunxi-ng/ccu_common.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/drivers/clk/sunxi-ng/ccu_common.c b/drivers/clk/sunxi-ng/ccu_common.c new file mode 100644 index 000000000..8d28a7a07 --- /dev/null +++ b/drivers/clk/sunxi-ng/ccu_common.c @@ -0,0 +1,219 @@ +// 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); + +/* + * 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"); |