From 9d9f78ed9af0e465d2fd15550471956e7f559b9f Mon Sep 17 00:00:00 2001 From: Mike Turquette Date: Thu, 15 Mar 2012 23:11:20 -0700 Subject: clk: basic clock hardware types Many platforms support simple gateable clocks, fixed-rate clocks, adjustable divider clocks and multi-parent multiplexer clocks. This patch introduces basic clock types for the above-mentioned hardware which share some common characteristics. Based on original work by Jeremy Kerr and contribution by Jamie Iles. Dividers and multiplexor clocks originally contributed by Richard Zhao & Sascha Hauer. Signed-off-by: Mike Turquette Signed-off-by: Mike Turquette Reviewed-by: Andrew Lunn Tested-by: Andrew Lunn Reviewed-by: Rob Herring Cc: Russell King Cc: Jeremy Kerr Cc: Thomas Gleixner Cc: Arnd Bergman Cc: Paul Walmsley Cc: Shawn Guo Cc: Sascha Hauer Cc: Jamie Iles Cc: Richard Zhao Cc: Saravana Kannan Cc: Magnus Damm Cc: Mark Brown Cc: Linus Walleij Cc: Stephen Boyd Cc: Amit Kucheria Cc: Deepak Saxena Cc: Grant Likely Signed-off-by: Arnd Bergmann --- drivers/clk/clk-gate.c | 150 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) create mode 100644 drivers/clk/clk-gate.c (limited to 'drivers/clk/clk-gate.c') diff --git a/drivers/clk/clk-gate.c b/drivers/clk/clk-gate.c new file mode 100644 index 000000000000..b5902e2ef2fd --- /dev/null +++ b/drivers/clk/clk-gate.c @@ -0,0 +1,150 @@ +/* + * Copyright (C) 2010-2011 Canonical Ltd + * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Gated clock implementation + */ + +#include +#include +#include +#include +#include +#include + +/** + * DOC: basic gatable clock which can gate and ungate it's ouput + * + * Traits of this clock: + * prepare - clk_(un)prepare only ensures parent is (un)prepared + * enable - clk_enable and clk_disable are functional & control gating + * rate - inherits rate from parent. No clk_set_rate support + * parent - fixed parent. No clk_set_parent support + */ + +#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw) + +static void clk_gate_set_bit(struct clk_gate *gate) +{ + u32 reg; + unsigned long flags = 0; + + if (gate->lock) + spin_lock_irqsave(gate->lock, flags); + + reg = readl(gate->reg); + reg |= BIT(gate->bit_idx); + writel(reg, gate->reg); + + if (gate->lock) + spin_unlock_irqrestore(gate->lock, flags); +} + +static void clk_gate_clear_bit(struct clk_gate *gate) +{ + u32 reg; + unsigned long flags = 0; + + if (gate->lock) + spin_lock_irqsave(gate->lock, flags); + + reg = readl(gate->reg); + reg &= ~BIT(gate->bit_idx); + writel(reg, gate->reg); + + if (gate->lock) + spin_unlock_irqrestore(gate->lock, flags); +} + +static int clk_gate_enable(struct clk_hw *hw) +{ + struct clk_gate *gate = to_clk_gate(hw); + + if (gate->flags & CLK_GATE_SET_TO_DISABLE) + clk_gate_clear_bit(gate); + else + clk_gate_set_bit(gate); + + return 0; +} +EXPORT_SYMBOL_GPL(clk_gate_enable); + +static void clk_gate_disable(struct clk_hw *hw) +{ + struct clk_gate *gate = to_clk_gate(hw); + + if (gate->flags & CLK_GATE_SET_TO_DISABLE) + clk_gate_set_bit(gate); + else + clk_gate_clear_bit(gate); +} +EXPORT_SYMBOL_GPL(clk_gate_disable); + +static int clk_gate_is_enabled(struct clk_hw *hw) +{ + u32 reg; + struct clk_gate *gate = to_clk_gate(hw); + + reg = readl(gate->reg); + + /* if a set bit disables this clk, flip it before masking */ + if (gate->flags & CLK_GATE_SET_TO_DISABLE) + reg ^= BIT(gate->bit_idx); + + reg &= BIT(gate->bit_idx); + + return reg ? 1 : 0; +} +EXPORT_SYMBOL_GPL(clk_gate_is_enabled); + +struct clk_ops clk_gate_ops = { + .enable = clk_gate_enable, + .disable = clk_gate_disable, + .is_enabled = clk_gate_is_enabled, +}; +EXPORT_SYMBOL_GPL(clk_gate_ops); + +struct clk *clk_register_gate(struct device *dev, const char *name, + const char *parent_name, unsigned long flags, + void __iomem *reg, u8 bit_idx, + u8 clk_gate_flags, spinlock_t *lock) +{ + struct clk_gate *gate; + struct clk *clk; + + gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL); + + if (!gate) { + pr_err("%s: could not allocate gated clk\n", __func__); + return NULL; + } + + /* struct clk_gate assignments */ + gate->reg = reg; + gate->bit_idx = bit_idx; + gate->flags = clk_gate_flags; + gate->lock = lock; + + if (parent_name) { + gate->parent[0] = kstrdup(parent_name, GFP_KERNEL); + if (!gate->parent[0]) + goto out; + } + + clk = clk_register(dev, name, + &clk_gate_ops, &gate->hw, + gate->parent, + (parent_name ? 1 : 0), + flags); + if (clk) + return clk; +out: + kfree(gate->parent[0]); + kfree(gate); + + return NULL; +} -- cgit v1.2.3