diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-26 12:42:29 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-26 12:42:29 -0700 |
commit | 27953437059c64d14086196eb96f43c78caa9db3 (patch) | |
tree | 0cfd5fb21262a6db3de0c64462847b4c0c43e9df /drivers/clk/spear/clk-frac-synth.c | |
parent | 2c757fd5d1a92086f225a75a8fac7cab242d11b0 (diff) | |
parent | 3c0dec5f58b3c7b3627715126d1bf9b030a076f0 (diff) |
Merge tag 'clock' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull arm-soc clock driver changes from Olof Johansson:
"The new clock subsystem was merged in linux-3.4 without any users,
this now moves the first three platforms over to it: imx, mxs and
spear.
The series also contains the changes for the clock subsystem itself,
since Mike preferred to have it together with the platforms that
require these changes, in order to avoid interdependencies and
conflicts."
Fix up trivial conflicts in arch/arm/mach-kirkwood/common.c (code
removed in one branch, added OF support in another) and
drivers/dma/imx-sdma.c (independent changes next to each other).
* tag 'clock' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (97 commits)
clk: Fix CLK_SET_RATE_GATE flag validation in clk_set_rate().
clk: Provide dummy clk_unregister()
SPEAr: Update defconfigs
SPEAr: Add SMI NOR partition info in dts files
SPEAr: Switch to common clock framework
SPEAr: Call clk_prepare() before calling clk_enable
SPEAr: clk: Add General Purpose Timer Synthesizer clock
SPEAr: clk: Add Fractional Synthesizer clock
SPEAr: clk: Add Auxiliary Synthesizer clock
SPEAr: clk: Add VCO-PLL Synthesizer clock
SPEAr: Add DT bindings for SPEAr's timer
ARM i.MX: remove now unused clock files
ARM: i.MX6: implement clocks using common clock framework
ARM i.MX35: implement clocks using common clock framework
ARM i.MX5: implement clocks using common clock framework
ARM: Kirkwood: Replace clock gating
ARM: Orion: Audio: Add clk/clkdev support
ARM: Orion: PCIE: Add support for clk
ARM: Orion: XOR: Add support for clk
ARM: Orion: CESA: Add support for clk
...
Diffstat (limited to 'drivers/clk/spear/clk-frac-synth.c')
-rw-r--r-- | drivers/clk/spear/clk-frac-synth.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/drivers/clk/spear/clk-frac-synth.c b/drivers/clk/spear/clk-frac-synth.c new file mode 100644 index 000000000000..4dbdb3fe18e0 --- /dev/null +++ b/drivers/clk/spear/clk-frac-synth.c @@ -0,0 +1,165 @@ +/* + * Copyright (C) 2012 ST Microelectronics + * Viresh Kumar <viresh.kumar@st.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + * + * Fractional Synthesizer clock implementation + */ + +#define pr_fmt(fmt) "clk-frac-synth: " fmt + +#include <linux/clk-provider.h> +#include <linux/slab.h> +#include <linux/io.h> +#include <linux/err.h> +#include "clk.h" + +#define DIV_FACTOR_MASK 0x1FFFF + +/* + * DOC: Fractional Synthesizer clock + * + * Fout from synthesizer can be given from below equation: + * + * Fout= Fin/2*div (division factor) + * div is 17 bits:- + * 0-13 (fractional part) + * 14-16 (integer part) + * div is (16-14 bits).(13-0 bits) (in binary) + * + * Fout = Fin/(2 * div) + * Fout = ((Fin / 10000)/(2 * div)) * 10000 + * Fout = (2^14 * (Fin / 10000)/(2^14 * (2 * div))) * 10000 + * Fout = (((Fin / 10000) << 14)/(2 * (div << 14))) * 10000 + * + * div << 14 simply 17 bit value written at register. + * Max error due to scaling down by 10000 is 10 KHz + */ + +#define to_clk_frac(_hw) container_of(_hw, struct clk_frac, hw) + +static unsigned long frac_calc_rate(struct clk_hw *hw, unsigned long prate, + int index) +{ + struct clk_frac *frac = to_clk_frac(hw); + struct frac_rate_tbl *rtbl = frac->rtbl; + + prate /= 10000; + prate <<= 14; + prate /= (2 * rtbl[index].div); + prate *= 10000; + + return prate; +} + +static long clk_frac_round_rate(struct clk_hw *hw, unsigned long drate, + unsigned long *prate) +{ + struct clk_frac *frac = to_clk_frac(hw); + int unused; + + return clk_round_rate_index(hw, drate, *prate, frac_calc_rate, + frac->rtbl_cnt, &unused); +} + +static unsigned long clk_frac_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_frac *frac = to_clk_frac(hw); + unsigned long flags = 0; + unsigned int div = 1, val; + + if (frac->lock) + spin_lock_irqsave(frac->lock, flags); + + val = readl_relaxed(frac->reg); + + if (frac->lock) + spin_unlock_irqrestore(frac->lock, flags); + + div = val & DIV_FACTOR_MASK; + + if (!div) + return 0; + + parent_rate = parent_rate / 10000; + + parent_rate = (parent_rate << 14) / (2 * div); + return parent_rate * 10000; +} + +/* Configures new clock rate of frac */ +static int clk_frac_set_rate(struct clk_hw *hw, unsigned long drate, + unsigned long prate) +{ + struct clk_frac *frac = to_clk_frac(hw); + struct frac_rate_tbl *rtbl = frac->rtbl; + unsigned long flags = 0, val; + int i; + + clk_round_rate_index(hw, drate, prate, frac_calc_rate, frac->rtbl_cnt, + &i); + + if (frac->lock) + spin_lock_irqsave(frac->lock, flags); + + val = readl_relaxed(frac->reg) & ~DIV_FACTOR_MASK; + val |= rtbl[i].div & DIV_FACTOR_MASK; + writel_relaxed(val, frac->reg); + + if (frac->lock) + spin_unlock_irqrestore(frac->lock, flags); + + return 0; +} + +struct clk_ops clk_frac_ops = { + .recalc_rate = clk_frac_recalc_rate, + .round_rate = clk_frac_round_rate, + .set_rate = clk_frac_set_rate, +}; + +struct clk *clk_register_frac(const char *name, const char *parent_name, + unsigned long flags, void __iomem *reg, + struct frac_rate_tbl *rtbl, u8 rtbl_cnt, spinlock_t *lock) +{ + struct clk_init_data init; + struct clk_frac *frac; + struct clk *clk; + + if (!name || !parent_name || !reg || !rtbl || !rtbl_cnt) { + pr_err("Invalid arguments passed"); + return ERR_PTR(-EINVAL); + } + + frac = kzalloc(sizeof(*frac), GFP_KERNEL); + if (!frac) { + pr_err("could not allocate frac clk\n"); + return ERR_PTR(-ENOMEM); + } + + /* struct clk_frac assignments */ + frac->reg = reg; + frac->rtbl = rtbl; + frac->rtbl_cnt = rtbl_cnt; + frac->lock = lock; + frac->hw.init = &init; + + init.name = name; + init.ops = &clk_frac_ops; + init.flags = flags; + init.parent_names = &parent_name; + init.num_parents = 1; + + clk = clk_register(NULL, &frac->hw); + if (!IS_ERR_OR_NULL(clk)) + return clk; + + pr_err("clk register failed\n"); + kfree(frac); + + return NULL; +} |