diff options
Diffstat (limited to 'drivers/clk/clk-mux.c')
| -rw-r--r-- | drivers/clk/clk-mux.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c new file mode 100644 index 000000000..e54e79714 --- /dev/null +++ b/drivers/clk/clk-mux.c @@ -0,0 +1,250 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de> + * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org> + * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org> + * + * Simple multiplexer clock implementation + */ + +#include <linux/clk-provider.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/io.h> +#include <linux/err.h> + +/* + * DOC: basic adjustable multiplexer clock that cannot gate + * + * Traits of this clock: + * prepare - clk_prepare only ensures that parents are prepared + * enable - clk_enable only ensures that parents are enabled + * rate - rate is only affected by parent switching. No clk_set_rate support + * parent - parent is adjustable through clk_set_parent + */ + +static inline u32 clk_mux_readl(struct clk_mux *mux) +{ + if (mux->flags & CLK_MUX_BIG_ENDIAN) + return ioread32be(mux->reg); + + return readl(mux->reg); +} + +static inline void clk_mux_writel(struct clk_mux *mux, u32 val) +{ + if (mux->flags & CLK_MUX_BIG_ENDIAN) + iowrite32be(val, mux->reg); + else + writel(val, mux->reg); +} + +int clk_mux_val_to_index(struct clk_hw *hw, u32 *table, unsigned int flags, + unsigned int val) +{ + int num_parents = clk_hw_get_num_parents(hw); + + if (table) { + int i; + + for (i = 0; i < num_parents; i++) + if (table[i] == val) + return i; + return -EINVAL; + } + + if (val && (flags & CLK_MUX_INDEX_BIT)) + val = ffs(val) - 1; + + if (val && (flags & CLK_MUX_INDEX_ONE)) + val--; + + if (val >= num_parents) + return -EINVAL; + + return val; +} +EXPORT_SYMBOL_GPL(clk_mux_val_to_index); + +unsigned int clk_mux_index_to_val(u32 *table, unsigned int flags, u8 index) +{ + unsigned int val = index; + + if (table) { + val = table[index]; + } else { + if (flags & CLK_MUX_INDEX_BIT) + val = 1 << index; + + if (flags & CLK_MUX_INDEX_ONE) + val++; + } + + return val; +} +EXPORT_SYMBOL_GPL(clk_mux_index_to_val); + +static u8 clk_mux_get_parent(struct clk_hw *hw) +{ + struct clk_mux *mux = to_clk_mux(hw); + u32 val; + + val = clk_mux_readl(mux) >> mux->shift; + val &= mux->mask; + + return clk_mux_val_to_index(hw, mux->table, mux->flags, val); +} + +static int clk_mux_set_parent(struct clk_hw *hw, u8 index) +{ + struct clk_mux *mux = to_clk_mux(hw); + u32 val = clk_mux_index_to_val(mux->table, mux->flags, index); + unsigned long flags = 0; + u32 reg; + + if (mux->lock) + spin_lock_irqsave(mux->lock, flags); + else + __acquire(mux->lock); + + if (mux->flags & CLK_MUX_HIWORD_MASK) { + reg = mux->mask << (mux->shift + 16); + } else { + reg = clk_mux_readl(mux); + reg &= ~(mux->mask << mux->shift); + } + val = val << mux->shift; + reg |= val; + clk_mux_writel(mux, reg); + + if (mux->lock) + spin_unlock_irqrestore(mux->lock, flags); + else + __release(mux->lock); + + return 0; +} + +static int clk_mux_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + struct clk_mux *mux = to_clk_mux(hw); + + return clk_mux_determine_rate_flags(hw, req, mux->flags); +} + +const struct clk_ops clk_mux_ops = { + .get_parent = clk_mux_get_parent, + .set_parent = clk_mux_set_parent, + .determine_rate = clk_mux_determine_rate, +}; +EXPORT_SYMBOL_GPL(clk_mux_ops); + +const struct clk_ops clk_mux_ro_ops = { + .get_parent = clk_mux_get_parent, +}; +EXPORT_SYMBOL_GPL(clk_mux_ro_ops); + +struct clk_hw *__clk_hw_register_mux(struct device *dev, struct device_node *np, + const char *name, u8 num_parents, + const char * const *parent_names, + const struct clk_hw **parent_hws, + const struct clk_parent_data *parent_data, + unsigned long flags, void __iomem *reg, u8 shift, u32 mask, + u8 clk_mux_flags, u32 *table, spinlock_t *lock) +{ + struct clk_mux *mux; + struct clk_hw *hw; + struct clk_init_data init = {}; + u8 width = 0; + int ret = -EINVAL; + + if (clk_mux_flags & CLK_MUX_HIWORD_MASK) { + width = fls(mask) - ffs(mask) + 1; + if (width + shift > 16) { + pr_err("mux value exceeds LOWORD field\n"); + return ERR_PTR(-EINVAL); + } + } + + /* allocate the mux */ + mux = kzalloc(sizeof(*mux), GFP_KERNEL); + if (!mux) + return ERR_PTR(-ENOMEM); + + init.name = name; + if (clk_mux_flags & CLK_MUX_READ_ONLY) + init.ops = &clk_mux_ro_ops; + else + init.ops = &clk_mux_ops; + init.flags = flags; + init.parent_names = parent_names; + init.parent_data = parent_data; + init.parent_hws = parent_hws; + init.num_parents = num_parents; + + /* struct clk_mux assignments */ + mux->reg = reg; + mux->shift = shift; + mux->mask = mask; + mux->flags = clk_mux_flags; + mux->lock = lock; + mux->table = table; + mux->hw.init = &init; + + hw = &mux->hw; + if (dev || !np) + ret = clk_hw_register(dev, hw); + else if (np) + ret = of_clk_hw_register(np, hw); + if (ret) { + kfree(mux); + hw = ERR_PTR(ret); + } + + return hw; +} +EXPORT_SYMBOL_GPL(__clk_hw_register_mux); + +struct clk *clk_register_mux_table(struct device *dev, const char *name, + const char * const *parent_names, u8 num_parents, + unsigned long flags, void __iomem *reg, u8 shift, u32 mask, + u8 clk_mux_flags, u32 *table, spinlock_t *lock) +{ + struct clk_hw *hw; + + hw = clk_hw_register_mux_table(dev, name, parent_names, + num_parents, flags, reg, shift, mask, + clk_mux_flags, table, lock); + if (IS_ERR(hw)) + return ERR_CAST(hw); + return hw->clk; +} +EXPORT_SYMBOL_GPL(clk_register_mux_table); + +void clk_unregister_mux(struct clk *clk) +{ + struct clk_mux *mux; + struct clk_hw *hw; + + hw = __clk_get_hw(clk); + if (!hw) + return; + + mux = to_clk_mux(hw); + + clk_unregister(clk); + kfree(mux); +} +EXPORT_SYMBOL_GPL(clk_unregister_mux); + +void clk_hw_unregister_mux(struct clk_hw *hw) +{ + struct clk_mux *mux; + + mux = to_clk_mux(hw); + + clk_hw_unregister(hw); + kfree(mux); +} +EXPORT_SYMBOL_GPL(clk_hw_unregister_mux); |