From 3d6ee287a3e341c88eafd0b4620b12d640b3736b Mon Sep 17 00:00:00 2001 From: Ulf Hansson Date: Tue, 12 Mar 2013 20:26:02 +0100 Subject: clk: Introduce optional is_prepared callback To reflect whether a clk_hw is prepared the clk_hw may implement the optional is_prepared callback. If not implemented we fall back to use the software prepare counter. Signed-off-by: Ulf Hansson Acked-by: Linus Walleij Signed-off-by: Mike Turquette --- include/linux/clk-provider.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include') diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 7f197d7addb0..ee946862e058 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -45,6 +45,10 @@ struct clk_hw; * undo any work done in the @prepare callback. Called with * prepare_lock held. * + * @is_prepared: Queries the hardware to determine if the clock is prepared. + * This function is allowed to sleep. Optional, if this op is not + * set then the prepare count will be used. + * * @enable: Enable the clock atomically. This must not return until the * clock is generating a valid clock signal, usable by consumer * devices. Called with enable_lock held. This function must not @@ -108,6 +112,7 @@ struct clk_hw; struct clk_ops { int (*prepare)(struct clk_hw *hw); void (*unprepare)(struct clk_hw *hw); + int (*is_prepared)(struct clk_hw *hw); int (*enable)(struct clk_hw *hw); void (*disable)(struct clk_hw *hw); int (*is_enabled)(struct clk_hw *hw); @@ -351,6 +356,7 @@ unsigned int __clk_get_enable_count(struct clk *clk); unsigned int __clk_get_prepare_count(struct clk *clk); unsigned long __clk_get_rate(struct clk *clk); unsigned long __clk_get_flags(struct clk *clk); +bool __clk_is_prepared(struct clk *clk); bool __clk_is_enabled(struct clk *clk); struct clk *__clk_lookup(const char *name); -- cgit v1.2.3 From 3cc8247f1dce79511de8bf0f69ab02a46cc315b7 Mon Sep 17 00:00:00 2001 From: Ulf Hansson Date: Tue, 12 Mar 2013 20:26:04 +0100 Subject: clk: Introduce optional unprepare_unused callback An unprepare_unused callback is introduced due to the same reasons to why the disable_unused callback was added. During the clk_disable_unused sequence, those clk_hw that needs specific treatment with regards to being unprepared, shall implement the unprepare_unused callback. Signed-off-by: Ulf Hansson Acked-by: Linus Walleij Signed-off-by: Mike Turquette --- drivers/clk/clk.c | 7 +++++-- include/linux/clk-provider.h | 5 +++++ 2 files changed, 10 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index c0141f3e1109..253792a46c08 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -352,9 +352,12 @@ static void clk_unprepare_unused_subtree(struct clk *clk) if (clk->flags & CLK_IGNORE_UNUSED) return; - if (__clk_is_prepared(clk)) - if (clk->ops->unprepare) + if (__clk_is_prepared(clk)) { + if (clk->ops->unprepare_unused) + clk->ops->unprepare_unused(clk->hw); + else if (clk->ops->unprepare) clk->ops->unprepare(clk->hw); + } } /* caller must hold prepare_lock */ diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index ee946862e058..56e6cc12c796 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -49,6 +49,10 @@ struct clk_hw; * This function is allowed to sleep. Optional, if this op is not * set then the prepare count will be used. * + * @unprepare_unused: Unprepare the clock atomically. Only called from + * clk_disable_unused for prepare clocks with special needs. + * Called with prepare mutex held. This function may sleep. + * * @enable: Enable the clock atomically. This must not return until the * clock is generating a valid clock signal, usable by consumer * devices. Called with enable_lock held. This function must not @@ -113,6 +117,7 @@ struct clk_ops { int (*prepare)(struct clk_hw *hw); void (*unprepare)(struct clk_hw *hw); int (*is_prepared)(struct clk_hw *hw); + void (*unprepare_unused)(struct clk_hw *hw); int (*enable)(struct clk_hw *hw); void (*disable)(struct clk_hw *hw); int (*is_enabled)(struct clk_hw *hw); -- cgit v1.2.3 From ce4f3313b05c836c21a91ac89f87dccf84ce9561 Mon Sep 17 00:00:00 2001 From: Peter De Schrijver Date: Fri, 22 Mar 2013 14:07:53 +0200 Subject: clk: add table lookup to mux Add a table lookup feature to the mux clock. Also allow arbitrary masks instead of the width. This will be used by some clocks on Tegra114. Also adapt the tegra periph clk because it uses struct clk_mux directly. Signed-off-by: Peter De Schrijver Tested-by: Stephen Warren Signed-off-by: Mike Turquette --- drivers/clk/clk-mux.c | 50 ++++++++++++++++++++++++++++++++++---------- drivers/clk/tegra/clk.h | 27 +++++++++++++++++------- include/linux/clk-private.h | 2 +- include/linux/clk-provider.h | 9 +++++++- 4 files changed, 67 insertions(+), 21 deletions(-) (limited to 'include') diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c index 508c032edce4..25b1734560d0 100644 --- a/drivers/clk/clk-mux.c +++ b/drivers/clk/clk-mux.c @@ -32,6 +32,7 @@ static u8 clk_mux_get_parent(struct clk_hw *hw) { struct clk_mux *mux = to_clk_mux(hw); + int num_parents = __clk_get_num_parents(hw->clk); u32 val; /* @@ -42,7 +43,16 @@ static u8 clk_mux_get_parent(struct clk_hw *hw) * val = 0x4 really means "bit 2, index starts at bit 0" */ val = readl(mux->reg) >> mux->shift; - val &= (1 << mux->width) - 1; + val &= mux->mask; + + if (mux->table) { + int i; + + for (i = 0; i < num_parents; i++) + if (mux->table[i] == val) + return i; + return -EINVAL; + } if (val && (mux->flags & CLK_MUX_INDEX_BIT)) val = ffs(val) - 1; @@ -50,7 +60,7 @@ static u8 clk_mux_get_parent(struct clk_hw *hw) if (val && (mux->flags & CLK_MUX_INDEX_ONE)) val--; - if (val >= __clk_get_num_parents(hw->clk)) + if (val >= num_parents) return -EINVAL; return val; @@ -62,17 +72,22 @@ static int clk_mux_set_parent(struct clk_hw *hw, u8 index) u32 val; unsigned long flags = 0; - if (mux->flags & CLK_MUX_INDEX_BIT) - index = (1 << ffs(index)); + if (mux->table) + index = mux->table[index]; - if (mux->flags & CLK_MUX_INDEX_ONE) - index++; + else { + if (mux->flags & CLK_MUX_INDEX_BIT) + index = (1 << ffs(index)); + + if (mux->flags & CLK_MUX_INDEX_ONE) + index++; + } if (mux->lock) spin_lock_irqsave(mux->lock, flags); val = readl(mux->reg); - val &= ~(((1 << mux->width) - 1) << mux->shift); + val &= ~(mux->mask << mux->shift); val |= index << mux->shift; writel(val, mux->reg); @@ -88,10 +103,10 @@ const struct clk_ops clk_mux_ops = { }; EXPORT_SYMBOL_GPL(clk_mux_ops); -struct clk *clk_register_mux(struct device *dev, const char *name, +struct clk *clk_register_mux_table(struct device *dev, const char *name, const char **parent_names, u8 num_parents, unsigned long flags, - void __iomem *reg, u8 shift, u8 width, - u8 clk_mux_flags, spinlock_t *lock) + void __iomem *reg, u8 shift, u32 mask, + u8 clk_mux_flags, u32 *table, spinlock_t *lock) { struct clk_mux *mux; struct clk *clk; @@ -113,9 +128,10 @@ struct clk *clk_register_mux(struct device *dev, const char *name, /* struct clk_mux assignments */ mux->reg = reg; mux->shift = shift; - mux->width = width; + mux->mask = mask; mux->flags = clk_mux_flags; mux->lock = lock; + mux->table = table; mux->hw.init = &init; clk = clk_register(dev, &mux->hw); @@ -125,3 +141,15 @@ struct clk *clk_register_mux(struct device *dev, const char *name, return clk; } + +struct clk *clk_register_mux(struct device *dev, const char *name, + const char **parent_names, u8 num_parents, unsigned long flags, + void __iomem *reg, u8 shift, u8 width, + u8 clk_mux_flags, spinlock_t *lock) +{ + u32 mask = BIT(width) - 1; + + return clk_register_mux_table(dev, name, parent_names, num_parents, + flags, reg, shift, mask, clk_mux_flags, + NULL, lock); +} diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h index 0744731c6229..a09d7dcaf183 100644 --- a/drivers/clk/tegra/clk.h +++ b/drivers/clk/tegra/clk.h @@ -355,15 +355,16 @@ struct clk *tegra_clk_register_periph_nodiv(const char *name, struct tegra_clk_periph *periph, void __iomem *clk_base, u32 offset); -#define TEGRA_CLK_PERIPH(_mux_shift, _mux_width, _mux_flags, \ +#define TEGRA_CLK_PERIPH(_mux_shift, _mux_mask, _mux_flags, \ _div_shift, _div_width, _div_frac_width, \ _div_flags, _clk_num, _enb_refcnt, _regs, \ - _gate_flags) \ + _gate_flags, _table) \ { \ .mux = { \ .flags = _mux_flags, \ .shift = _mux_shift, \ - .width = _mux_width, \ + .mask = _mux_mask, \ + .table = _table, \ }, \ .divider = { \ .flags = _div_flags, \ @@ -393,26 +394,36 @@ struct tegra_periph_init_data { const char *dev_id; }; -#define TEGRA_INIT_DATA(_name, _con_id, _dev_id, _parent_names, _offset, \ - _mux_shift, _mux_width, _mux_flags, _div_shift, \ +#define TEGRA_INIT_DATA_TABLE(_name, _con_id, _dev_id, _parent_names, _offset,\ + _mux_shift, _mux_mask, _mux_flags, _div_shift, \ _div_width, _div_frac_width, _div_flags, _regs, \ - _clk_num, _enb_refcnt, _gate_flags, _clk_id) \ + _clk_num, _enb_refcnt, _gate_flags, _clk_id, _table) \ { \ .name = _name, \ .clk_id = _clk_id, \ .parent_names = _parent_names, \ .num_parents = ARRAY_SIZE(_parent_names), \ - .periph = TEGRA_CLK_PERIPH(_mux_shift, _mux_width, \ + .periph = TEGRA_CLK_PERIPH(_mux_shift, _mux_mask, \ _mux_flags, _div_shift, \ _div_width, _div_frac_width, \ _div_flags, _clk_num, \ _enb_refcnt, _regs, \ - _gate_flags), \ + _gate_flags, _table), \ .offset = _offset, \ .con_id = _con_id, \ .dev_id = _dev_id, \ } +#define TEGRA_INIT_DATA(_name, _con_id, _dev_id, _parent_names, _offset,\ + _mux_shift, _mux_width, _mux_flags, _div_shift, \ + _div_width, _div_frac_width, _div_flags, _regs, \ + _clk_num, _enb_refcnt, _gate_flags, _clk_id) \ + TEGRA_INIT_DATA_TABLE(_name, _con_id, _dev_id, _parent_names, _offset,\ + _mux_shift, BIT(_mux_width) - 1, _mux_flags, \ + _div_shift, _div_width, _div_frac_width, _div_flags, \ + _regs, _clk_num, _enb_refcnt, _gate_flags, _clk_id,\ + NULL) + /** * struct clk_super_mux - super clock * diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h index 9c7f5807824b..dd7adff76e81 100644 --- a/include/linux/clk-private.h +++ b/include/linux/clk-private.h @@ -152,7 +152,7 @@ struct clk { }, \ .reg = _reg, \ .shift = _shift, \ - .width = _width, \ + .mask = BIT(_width) - 1, \ .flags = _mux_flags, \ .lock = _lock, \ }; \ diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 56e6cc12c796..63ba3b740794 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -297,8 +297,9 @@ struct clk *clk_register_divider_table(struct device *dev, const char *name, struct clk_mux { struct clk_hw hw; void __iomem *reg; + u32 *table; + u32 mask; u8 shift; - u8 width; u8 flags; spinlock_t *lock; }; @@ -307,11 +308,17 @@ struct clk_mux { #define CLK_MUX_INDEX_BIT BIT(1) extern const struct clk_ops clk_mux_ops; + struct clk *clk_register_mux(struct device *dev, const char *name, const char **parent_names, u8 num_parents, unsigned long flags, void __iomem *reg, u8 shift, u8 width, u8 clk_mux_flags, spinlock_t *lock); +struct clk *clk_register_mux_table(struct device *dev, const char *name, + const char **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_fixed_factor - fixed multiplier and divider clock * -- cgit v1.2.3 From ece70094f6ab2107d4313fa1802b13dab0234ac5 Mon Sep 17 00:00:00 2001 From: Prashant Gaikwad Date: Wed, 20 Mar 2013 17:30:34 +0530 Subject: clk: Add composite clock type Not all clocks are required to be decomposed into basic clock types but at the same time want to use the functionality provided by these basic clock types instead of duplicating. For example, Tegra SoC has ~100 clocks which can be decomposed into Mux -> Div -> Gate clock types making the clock count to ~300. Also, parent change operation can not be performed on gate clock which forces to use mux clock in driver if want to change the parent. Instead aggregate the basic clock types functionality into one clock and just use this clock for all operations. This clock type re-uses the functionality of basic clock types and not limited to basic clock types but any hardware-specific implementation. Signed-off-by: Prashant Gaikwad Signed-off-by: Mike Turquette --- drivers/clk/Makefile | 1 + drivers/clk/clk-composite.c | 201 +++++++++++++++++++++++++++++++++++++++++++ include/linux/clk-provider.h | 31 +++++++ 3 files changed, 233 insertions(+) create mode 100644 drivers/clk/clk-composite.c (limited to 'include') diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 1c22f9dc721d..41cb123a2d02 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -7,6 +7,7 @@ obj-$(CONFIG_COMMON_CLK) += clk-fixed-factor.o obj-$(CONFIG_COMMON_CLK) += clk-fixed-rate.o obj-$(CONFIG_COMMON_CLK) += clk-gate.o obj-$(CONFIG_COMMON_CLK) += clk-mux.o +obj-$(CONFIG_COMMON_CLK) += clk-composite.o # SoCs specific obj-$(CONFIG_ARCH_BCM2835) += clk-bcm2835.o diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c new file mode 100644 index 000000000000..097dee4fd209 --- /dev/null +++ b/drivers/clk/clk-composite.c @@ -0,0 +1,201 @@ +/* + * Copyright (c) 2013 NVIDIA CORPORATION. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#include +#include +#include +#include + +#define to_clk_composite(_hw) container_of(_hw, struct clk_composite, hw) + +static u8 clk_composite_get_parent(struct clk_hw *hw) +{ + struct clk_composite *composite = to_clk_composite(hw); + const struct clk_ops *mux_ops = composite->mux_ops; + struct clk_hw *mux_hw = composite->mux_hw; + + mux_hw->clk = hw->clk; + + return mux_ops->get_parent(mux_hw); +} + +static int clk_composite_set_parent(struct clk_hw *hw, u8 index) +{ + struct clk_composite *composite = to_clk_composite(hw); + const struct clk_ops *mux_ops = composite->mux_ops; + struct clk_hw *mux_hw = composite->mux_hw; + + mux_hw->clk = hw->clk; + + return mux_ops->set_parent(mux_hw, index); +} + +static unsigned long clk_composite_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_composite *composite = to_clk_composite(hw); + const struct clk_ops *div_ops = composite->div_ops; + struct clk_hw *div_hw = composite->div_hw; + + div_hw->clk = hw->clk; + + return div_ops->recalc_rate(div_hw, parent_rate); +} + +static long clk_composite_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + struct clk_composite *composite = to_clk_composite(hw); + const struct clk_ops *div_ops = composite->div_ops; + struct clk_hw *div_hw = composite->div_hw; + + div_hw->clk = hw->clk; + + return div_ops->round_rate(div_hw, rate, prate); +} + +static int clk_composite_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_composite *composite = to_clk_composite(hw); + const struct clk_ops *div_ops = composite->div_ops; + struct clk_hw *div_hw = composite->div_hw; + + div_hw->clk = hw->clk; + + return div_ops->set_rate(div_hw, rate, parent_rate); +} + +static int clk_composite_is_enabled(struct clk_hw *hw) +{ + struct clk_composite *composite = to_clk_composite(hw); + const struct clk_ops *gate_ops = composite->gate_ops; + struct clk_hw *gate_hw = composite->gate_hw; + + gate_hw->clk = hw->clk; + + return gate_ops->is_enabled(gate_hw); +} + +static int clk_composite_enable(struct clk_hw *hw) +{ + struct clk_composite *composite = to_clk_composite(hw); + const struct clk_ops *gate_ops = composite->gate_ops; + struct clk_hw *gate_hw = composite->gate_hw; + + gate_hw->clk = hw->clk; + + return gate_ops->enable(gate_hw); +} + +static void clk_composite_disable(struct clk_hw *hw) +{ + struct clk_composite *composite = to_clk_composite(hw); + const struct clk_ops *gate_ops = composite->gate_ops; + struct clk_hw *gate_hw = composite->gate_hw; + + gate_hw->clk = hw->clk; + + gate_ops->disable(gate_hw); +} + +struct clk *clk_register_composite(struct device *dev, const char *name, + const char **parent_names, int num_parents, + struct clk_hw *mux_hw, const struct clk_ops *mux_ops, + struct clk_hw *div_hw, const struct clk_ops *div_ops, + struct clk_hw *gate_hw, const struct clk_ops *gate_ops, + unsigned long flags) +{ + struct clk *clk; + struct clk_init_data init; + struct clk_composite *composite; + struct clk_ops *clk_composite_ops; + + composite = kzalloc(sizeof(*composite), GFP_KERNEL); + if (!composite) { + pr_err("%s: could not allocate composite clk\n", __func__); + return ERR_PTR(-ENOMEM); + } + + init.name = name; + init.flags = flags | CLK_IS_BASIC; + init.parent_names = parent_names; + init.num_parents = num_parents; + + clk_composite_ops = &composite->ops; + + if (mux_hw && mux_ops) { + if (!mux_ops->get_parent || !mux_ops->set_parent) { + clk = ERR_PTR(-EINVAL); + goto err; + } + + composite->mux_hw = mux_hw; + composite->mux_ops = mux_ops; + clk_composite_ops->get_parent = clk_composite_get_parent; + clk_composite_ops->set_parent = clk_composite_set_parent; + } + + if (div_hw && div_ops) { + if (!div_ops->recalc_rate || !div_ops->round_rate || + !div_ops->set_rate) { + clk = ERR_PTR(-EINVAL); + goto err; + } + + composite->div_hw = div_hw; + composite->div_ops = div_ops; + clk_composite_ops->recalc_rate = clk_composite_recalc_rate; + clk_composite_ops->round_rate = clk_composite_round_rate; + clk_composite_ops->set_rate = clk_composite_set_rate; + } + + if (gate_hw && gate_ops) { + if (!gate_ops->is_enabled || !gate_ops->enable || + !gate_ops->disable) { + clk = ERR_PTR(-EINVAL); + goto err; + } + + composite->gate_hw = gate_hw; + composite->gate_ops = gate_ops; + clk_composite_ops->is_enabled = clk_composite_is_enabled; + clk_composite_ops->enable = clk_composite_enable; + clk_composite_ops->disable = clk_composite_disable; + } + + init.ops = clk_composite_ops; + composite->hw.init = &init; + + clk = clk_register(dev, &composite->hw); + if (IS_ERR(clk)) + goto err; + + if (composite->mux_hw) + composite->mux_hw->clk = clk; + + if (composite->div_hw) + composite->div_hw->clk = clk; + + if (composite->gate_hw) + composite->gate_hw->clk = clk; + + return clk; + +err: + kfree(composite); + return clk; +} diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 63ba3b740794..1f0352802794 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -342,6 +342,37 @@ struct clk *clk_register_fixed_factor(struct device *dev, const char *name, const char *parent_name, unsigned long flags, unsigned int mult, unsigned int div); +/*** + * struct clk_composite - aggregate clock of mux, divider and gate clocks + * + * @hw: handle between common and hardware-specific interfaces + * @mux_hw: handle between composite and hardware-specifix mux clock + * @div_hw: handle between composite and hardware-specifix divider clock + * @gate_hw: handle between composite and hardware-specifix gate clock + * @mux_ops: clock ops for mux + * @div_ops: clock ops for divider + * @gate_ops: clock ops for gate + */ +struct clk_composite { + struct clk_hw hw; + struct clk_ops ops; + + struct clk_hw *mux_hw; + struct clk_hw *div_hw; + struct clk_hw *gate_hw; + + const struct clk_ops *mux_ops; + const struct clk_ops *div_ops; + const struct clk_ops *gate_ops; +}; + +struct clk *clk_register_composite(struct device *dev, const char *name, + const char **parent_names, int num_parents, + struct clk_hw *mux_hw, const struct clk_ops *mux_ops, + struct clk_hw *div_hw, const struct clk_ops *div_ops, + struct clk_hw *gate_hw, const struct clk_ops *gate_ops, + unsigned long flags); + /** * clk_register - allocate a new clock, register it and return an opaque cookie * @dev: device that is registering this clock -- cgit v1.2.3 From e874a6697710f52fa8ab29487a99034d5d96fdcc Mon Sep 17 00:00:00 2001 From: Emilio López Date: Mon, 25 Feb 2013 11:44:26 -0300 Subject: clk: arm: sunxi: Add a new clock driver for sunxi SOCs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This commit implements the base CPU clocks for sunxi devices. It has been tested using a slightly modified cpufreq driver from the linux-sunxi 3.0 tree. Additionally, document the new bindings introduced by this patch. Idling: / # cat /sys/kernel/debug/clk/clk_summary clock enable_cnt prepare_cnt rate --------------------------------------------------------------------- osc32k 0 0 32768 osc24M_fixed 0 0 24000000 osc24M 0 0 24000000 apb1_mux 0 0 24000000 apb1 0 0 24000000 pll1 0 0 60000000 cpu 0 0 60000000 axi 0 0 60000000 ahb 0 0 60000000 apb0 0 0 30000000 dummy 0 0 0 After "yes >/dev/null &": / # cat /sys/kernel/debug/clk/clk_summary clock enable_cnt prepare_cnt rate --------------------------------------------------------------------- osc32k 0 0 32768 osc24M_fixed 0 0 24000000 osc24M 0 0 24000000 apb1_mux 0 0 24000000 apb1 0 0 24000000 pll1 0 0 1008000000 cpu 0 0 1008000000 axi 0 0 336000000 ahb 0 0 168000000 apb0 0 0 84000000 dummy 0 0 0 Signed-off-by: Emilio López Acked-by: Maxime Ripard Signed-off-by: Mike Turquette --- Documentation/devicetree/bindings/clock/sunxi.txt | 44 +++ drivers/clk/Makefile | 1 + drivers/clk/sunxi/Makefile | 5 + drivers/clk/sunxi/clk-factors.c | 180 +++++++++++ drivers/clk/sunxi/clk-factors.h | 27 ++ drivers/clk/sunxi/clk-sunxi.c | 362 ++++++++++++++++++++++ drivers/clocksource/sunxi_timer.c | 4 +- include/linux/clk/sunxi.h | 22 ++ 8 files changed, 643 insertions(+), 2 deletions(-) create mode 100644 Documentation/devicetree/bindings/clock/sunxi.txt create mode 100644 drivers/clk/sunxi/Makefile create mode 100644 drivers/clk/sunxi/clk-factors.c create mode 100644 drivers/clk/sunxi/clk-factors.h create mode 100644 drivers/clk/sunxi/clk-sunxi.c create mode 100644 include/linux/clk/sunxi.h (limited to 'include') diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt new file mode 100644 index 000000000000..b23cfbdbcd6d --- /dev/null +++ b/Documentation/devicetree/bindings/clock/sunxi.txt @@ -0,0 +1,44 @@ +Device Tree Clock bindings for arch-sunxi + +This binding uses the common clock binding[1]. + +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt + +Required properties: +- compatible : shall be one of the following: + "allwinner,sunxi-osc-clk" - for a gatable oscillator + "allwinner,sunxi-pll1-clk" - for the main PLL clock + "allwinner,sunxi-cpu-clk" - for the CPU multiplexer clock + "allwinner,sunxi-axi-clk" - for the sunxi AXI clock + "allwinner,sunxi-ahb-clk" - for the sunxi AHB clock + "allwinner,sunxi-apb0-clk" - for the sunxi APB0 clock + "allwinner,sunxi-apb1-clk" - for the sunxi APB1 clock + "allwinner,sunxi-apb1-mux-clk" - for the sunxi APB1 clock muxing + +Required properties for all clocks: +- reg : shall be the control register address for the clock. +- clocks : shall be the input parent clock(s) phandle for the clock +- #clock-cells : from common clock binding; shall be set to 0. + +For example: + +osc24M: osc24M@01c20050 { + #clock-cells = <0>; + compatible = "allwinner,sunxi-osc-clk"; + reg = <0x01c20050 0x4>; + clocks = <&osc24M_fixed>; +}; + +pll1: pll1@01c20000 { + #clock-cells = <0>; + compatible = "allwinner,sunxi-pll1-clk"; + reg = <0x01c20000 0x4>; + clocks = <&osc24M>; +}; + +cpu: cpu@01c20054 { + #clock-cells = <0>; + compatible = "allwinner,sunxi-cpu-clk"; + reg = <0x01c20054 0x4>; + clocks = <&osc32k>, <&osc24M>, <&pll1>; +}; diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 41cb123a2d02..79e98e416724 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -24,6 +24,7 @@ ifeq ($(CONFIG_COMMON_CLK), y) obj-$(CONFIG_ARCH_MMP) += mmp/ endif obj-$(CONFIG_MACH_LOONGSON1) += clk-ls1x.o +obj-$(CONFIG_ARCH_SUNXI) += sunxi/ obj-$(CONFIG_ARCH_U8500) += ux500/ obj-$(CONFIG_ARCH_VT8500) += clk-vt8500.o obj-$(CONFIG_ARCH_ZYNQ) += clk-zynq.o diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile new file mode 100644 index 000000000000..b5bac917612c --- /dev/null +++ b/drivers/clk/sunxi/Makefile @@ -0,0 +1,5 @@ +# +# Makefile for sunxi specific clk +# + +obj-y += clk-sunxi.o clk-factors.o diff --git a/drivers/clk/sunxi/clk-factors.c b/drivers/clk/sunxi/clk-factors.c new file mode 100644 index 000000000000..88523f91d9b7 --- /dev/null +++ b/drivers/clk/sunxi/clk-factors.c @@ -0,0 +1,180 @@ +/* + * Copyright (C) 2013 Emilio López + * + * 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. + * + * Adjustable factor-based clock implementation + */ + +#include +#include +#include +#include +#include +#include + +#include + +#include "clk-factors.h" + +/* + * DOC: basic adjustable factor-based 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 adjustable. + * clk->rate = (parent->rate * N * (K + 1) >> P) / (M + 1) + * parent - fixed parent. No clk_set_parent support + */ + +struct clk_factors { + struct clk_hw hw; + void __iomem *reg; + struct clk_factors_config *config; + void (*get_factors) (u32 *rate, u32 parent, u8 *n, u8 *k, u8 *m, u8 *p); + spinlock_t *lock; +}; + +#define to_clk_factors(_hw) container_of(_hw, struct clk_factors, hw) + +#define SETMASK(len, pos) (((-1U) >> (31-len)) << (pos)) +#define CLRMASK(len, pos) (~(SETMASK(len, pos))) +#define FACTOR_GET(bit, len, reg) (((reg) & SETMASK(len, bit)) >> (bit)) + +#define FACTOR_SET(bit, len, reg, val) \ + (((reg) & CLRMASK(len, bit)) | (val << (bit))) + +static unsigned long clk_factors_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + u8 n = 1, k = 0, p = 0, m = 0; + u32 reg; + unsigned long rate; + struct clk_factors *factors = to_clk_factors(hw); + struct clk_factors_config *config = factors->config; + + /* Fetch the register value */ + reg = readl(factors->reg); + + /* Get each individual factor if applicable */ + if (config->nwidth != SUNXI_FACTORS_NOT_APPLICABLE) + n = FACTOR_GET(config->nshift, config->nwidth, reg); + if (config->kwidth != SUNXI_FACTORS_NOT_APPLICABLE) + k = FACTOR_GET(config->kshift, config->kwidth, reg); + if (config->mwidth != SUNXI_FACTORS_NOT_APPLICABLE) + m = FACTOR_GET(config->mshift, config->mwidth, reg); + if (config->pwidth != SUNXI_FACTORS_NOT_APPLICABLE) + p = FACTOR_GET(config->pshift, config->pwidth, reg); + + /* Calculate the rate */ + rate = (parent_rate * n * (k + 1) >> p) / (m + 1); + + return rate; +} + +static long clk_factors_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + struct clk_factors *factors = to_clk_factors(hw); + factors->get_factors((u32 *)&rate, (u32)*parent_rate, + NULL, NULL, NULL, NULL); + + return rate; +} + +static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + u8 n, k, m, p; + u32 reg; + struct clk_factors *factors = to_clk_factors(hw); + struct clk_factors_config *config = factors->config; + unsigned long flags = 0; + + factors->get_factors((u32 *)&rate, (u32)parent_rate, &n, &k, &m, &p); + + if (factors->lock) + spin_lock_irqsave(factors->lock, flags); + + /* Fetch the register value */ + reg = readl(factors->reg); + + /* Set up the new factors - macros do not do anything if width is 0 */ + reg = FACTOR_SET(config->nshift, config->nwidth, reg, n); + reg = FACTOR_SET(config->kshift, config->kwidth, reg, k); + reg = FACTOR_SET(config->mshift, config->mwidth, reg, m); + reg = FACTOR_SET(config->pshift, config->pwidth, reg, p); + + /* Apply them now */ + writel(reg, factors->reg); + + /* delay 500us so pll stabilizes */ + __delay((rate >> 20) * 500 / 2); + + if (factors->lock) + spin_unlock_irqrestore(factors->lock, flags); + + return 0; +} + +static const struct clk_ops clk_factors_ops = { + .recalc_rate = clk_factors_recalc_rate, + .round_rate = clk_factors_round_rate, + .set_rate = clk_factors_set_rate, +}; + +/** + * clk_register_factors - register a factors clock with + * the clock framework + * @dev: device registering this clock + * @name: name of this clock + * @parent_name: name of clock's parent + * @flags: framework-specific flags + * @reg: register address to adjust factors + * @config: shift and width of factors n, k, m and p + * @get_factors: function to calculate the factors for a given frequency + * @lock: shared register lock for this clock + */ +struct clk *clk_register_factors(struct device *dev, const char *name, + const char *parent_name, + unsigned long flags, void __iomem *reg, + struct clk_factors_config *config, + void (*get_factors)(u32 *rate, u32 parent, + u8 *n, u8 *k, u8 *m, u8 *p), + spinlock_t *lock) +{ + struct clk_factors *factors; + struct clk *clk; + struct clk_init_data init; + + /* allocate the factors */ + factors = kzalloc(sizeof(struct clk_factors), GFP_KERNEL); + if (!factors) { + pr_err("%s: could not allocate factors clk\n", __func__); + return ERR_PTR(-ENOMEM); + } + + init.name = name; + init.ops = &clk_factors_ops; + init.flags = flags; + init.parent_names = (parent_name ? &parent_name : NULL); + init.num_parents = (parent_name ? 1 : 0); + + /* struct clk_factors assignments */ + factors->reg = reg; + factors->config = config; + factors->lock = lock; + factors->hw.init = &init; + factors->get_factors = get_factors; + + /* register the clock */ + clk = clk_register(dev, &factors->hw); + + if (IS_ERR(clk)) + kfree(factors); + + return clk; +} diff --git a/drivers/clk/sunxi/clk-factors.h b/drivers/clk/sunxi/clk-factors.h new file mode 100644 index 000000000000..f49851cc4380 --- /dev/null +++ b/drivers/clk/sunxi/clk-factors.h @@ -0,0 +1,27 @@ +#ifndef __MACH_SUNXI_CLK_FACTORS_H +#define __MACH_SUNXI_CLK_FACTORS_H + +#include +#include + +#define SUNXI_FACTORS_NOT_APPLICABLE (0) + +struct clk_factors_config { + u8 nshift; + u8 nwidth; + u8 kshift; + u8 kwidth; + u8 mshift; + u8 mwidth; + u8 pshift; + u8 pwidth; +}; + +struct clk *clk_register_factors(struct device *dev, const char *name, + const char *parent_name, + unsigned long flags, void __iomem *reg, + struct clk_factors_config *config, + void (*get_factors) (u32 *rate, u32 parent_rate, + u8 *n, u8 *k, u8 *m, u8 *p), + spinlock_t *lock); +#endif diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c new file mode 100644 index 000000000000..d4ad1c22859e --- /dev/null +++ b/drivers/clk/sunxi/clk-sunxi.c @@ -0,0 +1,362 @@ +/* + * Copyright 2013 Emilio López + * + * Emilio López + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include +#include +#include +#include +#include + +#include "clk-factors.h" + +static DEFINE_SPINLOCK(clk_lock); + +/** + * sunxi_osc_clk_setup() - Setup function for gatable oscillator + */ + +#define SUNXI_OSC24M_GATE 0 + +static void __init sunxi_osc_clk_setup(struct device_node *node) +{ + struct clk *clk; + const char *clk_name = node->name; + const char *parent; + void *reg; + + reg = of_iomap(node, 0); + + parent = of_clk_get_parent_name(node, 0); + + clk = clk_register_gate(NULL, clk_name, parent, CLK_IGNORE_UNUSED, + reg, SUNXI_OSC24M_GATE, 0, &clk_lock); + + if (clk) { + of_clk_add_provider(node, of_clk_src_simple_get, clk); + clk_register_clkdev(clk, clk_name, NULL); + } +} + + + +/** + * sunxi_get_pll1_factors() - calculates n, k, m, p factors for PLL1 + * PLL1 rate is calculated as follows + * rate = (parent_rate * n * (k + 1) >> p) / (m + 1); + * parent_rate is always 24Mhz + */ + +static void sunxi_get_pll1_factors(u32 *freq, u32 parent_rate, + u8 *n, u8 *k, u8 *m, u8 *p) +{ + u8 div; + + /* Normalize value to a 6M multiple */ + div = *freq / 6000000; + *freq = 6000000 * div; + + /* we were called to round the frequency, we can now return */ + if (n == NULL) + return; + + /* m is always zero for pll1 */ + *m = 0; + + /* k is 1 only on these cases */ + if (*freq >= 768000000 || *freq == 42000000 || *freq == 54000000) + *k = 1; + else + *k = 0; + + /* p will be 3 for divs under 10 */ + if (div < 10) + *p = 3; + + /* p will be 2 for divs between 10 - 20 and odd divs under 32 */ + else if (div < 20 || (div < 32 && (div & 1))) + *p = 2; + + /* p will be 1 for even divs under 32, divs under 40 and odd pairs + * of divs between 40-62 */ + else if (div < 40 || (div < 64 && (div & 2))) + *p = 1; + + /* any other entries have p = 0 */ + else + *p = 0; + + /* calculate a suitable n based on k and p */ + div <<= *p; + div /= (*k + 1); + *n = div / 4; +} + + + +/** + * sunxi_get_apb1_factors() - calculates m, p factors for APB1 + * APB1 rate is calculated as follows + * rate = (parent_rate >> p) / (m + 1); + */ + +static void sunxi_get_apb1_factors(u32 *freq, u32 parent_rate, + u8 *n, u8 *k, u8 *m, u8 *p) +{ + u8 calcm, calcp; + + if (parent_rate < *freq) + *freq = parent_rate; + + parent_rate = (parent_rate + (*freq - 1)) / *freq; + + /* Invalid rate! */ + if (parent_rate > 32) + return; + + if (parent_rate <= 4) + calcp = 0; + else if (parent_rate <= 8) + calcp = 1; + else if (parent_rate <= 16) + calcp = 2; + else + calcp = 3; + + calcm = (parent_rate >> calcp) - 1; + + *freq = (parent_rate >> calcp) / (calcm + 1); + + /* we were called to round the frequency, we can now return */ + if (n == NULL) + return; + + *m = calcm; + *p = calcp; +} + + + +/** + * sunxi_factors_clk_setup() - Setup function for factor clocks + */ + +struct factors_data { + struct clk_factors_config *table; + void (*getter) (u32 *rate, u32 parent_rate, u8 *n, u8 *k, u8 *m, u8 *p); +}; + +static struct clk_factors_config pll1_config = { + .nshift = 8, + .nwidth = 5, + .kshift = 4, + .kwidth = 2, + .mshift = 0, + .mwidth = 2, + .pshift = 16, + .pwidth = 2, +}; + +static struct clk_factors_config apb1_config = { + .mshift = 0, + .mwidth = 5, + .pshift = 16, + .pwidth = 2, +}; + +static const __initconst struct factors_data pll1_data = { + .table = &pll1_config, + .getter = sunxi_get_pll1_factors, +}; + +static const __initconst struct factors_data apb1_data = { + .table = &apb1_config, + .getter = sunxi_get_apb1_factors, +}; + +static void __init sunxi_factors_clk_setup(struct device_node *node, + struct factors_data *data) +{ + struct clk *clk; + const char *clk_name = node->name; + const char *parent; + void *reg; + + reg = of_iomap(node, 0); + + parent = of_clk_get_parent_name(node, 0); + + clk = clk_register_factors(NULL, clk_name, parent, CLK_IGNORE_UNUSED, + reg, data->table, data->getter, &clk_lock); + + if (clk) { + of_clk_add_provider(node, of_clk_src_simple_get, clk); + clk_register_clkdev(clk, clk_name, NULL); + } +} + + + +/** + * sunxi_mux_clk_setup() - Setup function for muxes + */ + +#define SUNXI_MUX_GATE_WIDTH 2 + +struct mux_data { + u8 shift; +}; + +static const __initconst struct mux_data cpu_data = { + .shift = 16, +}; + +static const __initconst struct mux_data apb1_mux_data = { + .shift = 24, +}; + +static void __init sunxi_mux_clk_setup(struct device_node *node, + struct mux_data *data) +{ + struct clk *clk; + const char *clk_name = node->name; + const char **parents = kmalloc(sizeof(char *) * 5, GFP_KERNEL); + void *reg; + int i = 0; + + reg = of_iomap(node, 0); + + while (i < 5 && (parents[i] = of_clk_get_parent_name(node, i)) != NULL) + i++; + + clk = clk_register_mux(NULL, clk_name, parents, i, 0, reg, + data->shift, SUNXI_MUX_GATE_WIDTH, + 0, &clk_lock); + + if (clk) { + of_clk_add_provider(node, of_clk_src_simple_get, clk); + clk_register_clkdev(clk, clk_name, NULL); + } +} + + + +/** + * sunxi_divider_clk_setup() - Setup function for simple divider clocks + */ + +#define SUNXI_DIVISOR_WIDTH 2 + +struct div_data { + u8 shift; + u8 pow; +}; + +static const __initconst struct div_data axi_data = { + .shift = 0, + .pow = 0, +}; + +static const __initconst struct div_data ahb_data = { + .shift = 4, + .pow = 1, +}; + +static const __initconst struct div_data apb0_data = { + .shift = 8, + .pow = 1, +}; + +static void __init sunxi_divider_clk_setup(struct device_node *node, + struct div_data *data) +{ + struct clk *clk; + const char *clk_name = node->name; + const char *clk_parent; + void *reg; + + reg = of_iomap(node, 0); + + clk_parent = of_clk_get_parent_name(node, 0); + + clk = clk_register_divider(NULL, clk_name, clk_parent, 0, + reg, data->shift, SUNXI_DIVISOR_WIDTH, + data->pow ? CLK_DIVIDER_POWER_OF_TWO : 0, + &clk_lock); + if (clk) { + of_clk_add_provider(node, of_clk_src_simple_get, clk); + clk_register_clkdev(clk, clk_name, NULL); + } +} + + +/* Matches for of_clk_init */ +static const __initconst struct of_device_id clk_match[] = { + {.compatible = "fixed-clock", .data = of_fixed_clk_setup,}, + {.compatible = "allwinner,sunxi-osc-clk", .data = sunxi_osc_clk_setup,}, + {} +}; + +/* Matches for factors clocks */ +static const __initconst struct of_device_id clk_factors_match[] = { + {.compatible = "allwinner,sunxi-pll1-clk", .data = &pll1_data,}, + {.compatible = "allwinner,sunxi-apb1-clk", .data = &apb1_data,}, + {} +}; + +/* Matches for divider clocks */ +static const __initconst struct of_device_id clk_div_match[] = { + {.compatible = "allwinner,sunxi-axi-clk", .data = &axi_data,}, + {.compatible = "allwinner,sunxi-ahb-clk", .data = &ahb_data,}, + {.compatible = "allwinner,sunxi-apb0-clk", .data = &apb0_data,}, + {} +}; + +/* Matches for mux clocks */ +static const __initconst struct of_device_id clk_mux_match[] = { + {.compatible = "allwinner,sunxi-cpu-clk", .data = &cpu_data,}, + {.compatible = "allwinner,sunxi-apb1-mux-clk", .data = &apb1_mux_data,}, + {} +}; + +static void __init of_sunxi_table_clock_setup(const struct of_device_id *clk_match, + void *function) +{ + struct device_node *np; + const struct div_data *data; + const struct of_device_id *match; + void (*setup_function)(struct device_node *, const void *) = function; + + for_each_matching_node(np, clk_match) { + match = of_match_node(clk_match, np); + data = match->data; + setup_function(np, data); + } +} + +void __init sunxi_init_clocks(void) +{ + /* Register all the simple sunxi clocks on DT */ + of_clk_init(clk_match); + + /* Register factor clocks */ + of_sunxi_table_clock_setup(clk_factors_match, sunxi_factors_clk_setup); + + /* Register divider clocks */ + of_sunxi_table_clock_setup(clk_div_match, sunxi_divider_clk_setup); + + /* Register mux clocks */ + of_sunxi_table_clock_setup(clk_mux_match, sunxi_mux_clk_setup); +} diff --git a/drivers/clocksource/sunxi_timer.c b/drivers/clocksource/sunxi_timer.c index 4086b9167159..0ce85e29769b 100644 --- a/drivers/clocksource/sunxi_timer.c +++ b/drivers/clocksource/sunxi_timer.c @@ -23,7 +23,7 @@ #include #include #include -#include +#include #define TIMER_CTL_REG 0x00 #define TIMER_CTL_ENABLE (1 << 0) @@ -123,7 +123,7 @@ void __init sunxi_timer_init(void) if (irq <= 0) panic("Can't parse IRQ"); - of_clk_init(NULL); + sunxi_init_clocks(); clk = of_clk_get(node, 0); if (IS_ERR(clk)) diff --git a/include/linux/clk/sunxi.h b/include/linux/clk/sunxi.h new file mode 100644 index 000000000000..e074fdd5a236 --- /dev/null +++ b/include/linux/clk/sunxi.h @@ -0,0 +1,22 @@ +/* + * Copyright 2012 Maxime Ripard + * + * Maxime Ripard + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#ifndef __LINUX_CLK_SUNXI_H_ +#define __LINUX_CLK_SUNXI_H_ + +void __init sunxi_init_clocks(void); + +#endif -- cgit v1.2.3 From 3566d40c1a4617461b38c82059bdc41d622faa8b Mon Sep 17 00:00:00 2001 From: James Hogan Date: Mon, 25 Mar 2013 14:35:07 +0000 Subject: clk: fix clk_mux::flags kerneldoc The kerneldoc comment for struct clk_mux documented the non-existent num_clks instead of flags. Correct this. Signed-off-by: James Hogan Signed-off-by: Mike Turquette --- include/linux/clk-provider.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 1f0352802794..b1675074fe7c 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -284,7 +284,7 @@ struct clk *clk_register_divider_table(struct device *dev, const char *name, * @reg: register controlling multiplexer * @shift: shift to multiplexer bit field * @width: width of mutliplexer bit field - * @num_clks: number of parent clocks + * @flags: hardware-specific flags * @lock: register lock * * Clock with multiple selectable parents. Implements .get_parent, .set_parent -- cgit v1.2.3 From 056b205316cc3dcf8a67cf813a26ff8a72bf3cb9 Mon Sep 17 00:00:00 2001 From: Soren Brinkmann Date: Tue, 2 Apr 2013 15:36:56 -0700 Subject: clk: divider: Introduce CLK_DIVIDER_ALLOW_ZERO flag Dividers which have CLK_DIVIDER_ONE_BASED set have a redundant state, being a divider value of zero. Some hardware implementations allow a zero divider which simply doesn't alter the frequency. I.e. it acts like a divide by one or bypassing the divider. This flag is used to handle such HW in the clk-divider model. Signed-off-by: Soren Brinkmann Signed-off-by: Mike Turquette --- drivers/clk/clk-divider.c | 5 +++-- include/linux/clk-provider.h | 8 +++++++- 2 files changed, 10 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c index 68b402101170..6d9674160430 100644 --- a/drivers/clk/clk-divider.c +++ b/drivers/clk/clk-divider.c @@ -109,8 +109,9 @@ static unsigned long clk_divider_recalc_rate(struct clk_hw *hw, div = _get_div(divider, val); if (!div) { - WARN(1, "%s: Invalid divisor for clock %s\n", __func__, - __clk_get_name(hw->clk)); + WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO), + "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n", + __clk_get_name(hw->clk)); return parent_rate; } diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index b1675074fe7c..9fdfae74d669 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -249,9 +249,14 @@ struct clk_div_table { * CLK_DIVIDER_ONE_BASED - by default the divisor is the value read from the * register plus one. If CLK_DIVIDER_ONE_BASED is set then the divider is * the raw value read from the register, with the value of zero considered - * invalid + * invalid, unless CLK_DIVIDER_ALLOW_ZERO is set. * CLK_DIVIDER_POWER_OF_TWO - clock divisor is 2 raised to the value read from * the hardware register + * CLK_DIVIDER_ALLOW_ZERO - Allow zero divisors. For dividers which have + * CLK_DIVIDER_ONE_BASED set, it is possible to end up with a zero divisor. + * Some hardware implementations gracefully handle this case and allow a + * zero divisor by not modifying their input clock + * (divide by one / bypass). */ struct clk_divider { struct clk_hw hw; @@ -265,6 +270,7 @@ struct clk_divider { #define CLK_DIVIDER_ONE_BASED BIT(0) #define CLK_DIVIDER_POWER_OF_TWO BIT(1) +#define CLK_DIVIDER_ALLOW_ZERO BIT(2) extern const struct clk_ops clk_divider_ops; struct clk *clk_register_divider(struct device *dev, const char *name, -- cgit v1.2.3