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author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-11-05 12:59:36 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-11-05 12:59:36 -0800 |
commit | f66477a0aeb77f97a7de5f791700dadc42f3f792 (patch) | |
tree | 0a49febcf211c33948be618860eb3d545b7c6608 /drivers/clk/clk-multiplier.c | |
parent | 400c5bd5a5b1faf3089322ace58b974446a8ddc3 (diff) | |
parent | e5bf1991ea62b4f4fc906d0828f7eed988fc3835 (diff) | |
download | linux-f66477a0aeb77f97a7de5f791700dadc42f3f792.tar.bz2 |
Merge tag 'clk-for-linus-20151104' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
Pull clk updates from Stephen Boyd:
"The majority of the changes are driver updates and new device support.
The core framework is mostly unchanged this time around, with only a
couple patches to expose a clk provider API and make getting clk
parent names from DT more robust.
Driver updates:
- Support for clock controllers found on Broadcom Northstar SoCs and
bcm2835 SoC
- Support for Allwinner audio clocks
- A few cleanup patches for Tegra drivers and support for the highest
DFLL frequencies on Tegra124
- Samsung exynos7 fixes and improvements
- i.Mx SoC updates to add a few missing clocks and keep debug uart
clocks on during kernel intialization
- Some mediatek cleanups and support for more subsystem clocks
- Support for msm8916 gpu/audio clocks and qcom's GDSC power domain
controllers
- A new driver for the Silabs si514 clock chip"
* tag 'clk-for-linus-20151104' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: (143 commits)
clk: qcom: msm8960: Fix dsi1/2 halt bits
clk: lpc18xx-cgu: fix potential system hang when disabling unused clocks
clk: lpc18xx-ccu: fix potential system hang when disabling unused clocks
clk: Add clk_hw_is_enabled() for use by clk providers
clk: Add stubs for of_clk_*() APIs when CONFIG_OF=n
clk: versatile-icst: fix memory leak
clk: Remove clk_{register,unregister}_multiplier()
clk: iproc: define Broadcom NS2 iProc clock binding
clk: iproc: define Broadcom NSP iProc clock binding
clk: ns2: add clock support for Broadcom Northstar 2 SoC
clk: iproc: Separate status and control variables
clk: iproc: Split off dig_filter
clk: iproc: Add PLL base write function
clk: nsp: add clock support for Broadcom Northstar Plus SoC
clk: iproc: Add PWRCTRL support
clk: cygnus: Convert all macros to all caps
ARM: cygnus: fix link failures when CONFIG_COMMON_CLK_IPROC is disabled
clk: imx31: add missing of_node_put
clk: imx27: add missing of_node_put
clk: si5351: add missing of_node_put
...
Diffstat (limited to 'drivers/clk/clk-multiplier.c')
-rw-r--r-- | drivers/clk/clk-multiplier.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/drivers/clk/clk-multiplier.c b/drivers/clk/clk-multiplier.c new file mode 100644 index 000000000000..fe7806506bf3 --- /dev/null +++ b/drivers/clk/clk-multiplier.c @@ -0,0 +1,130 @@ +/* + * Copyright (C) 2015 Maxime Ripard <maxime.ripard@free-electrons.com> + * + * 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. + */ + +#include <linux/bitops.h> +#include <linux/clk-provider.h> +#include <linux/err.h> +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/of.h> +#include <linux/slab.h> + +#define to_clk_multiplier(_hw) container_of(_hw, struct clk_multiplier, hw) + +static unsigned long __get_mult(struct clk_multiplier *mult, + unsigned long rate, + unsigned long parent_rate) +{ + if (mult->flags & CLK_MULTIPLIER_ROUND_CLOSEST) + return DIV_ROUND_CLOSEST(rate, parent_rate); + + return rate / parent_rate; +} + +static unsigned long clk_multiplier_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_multiplier *mult = to_clk_multiplier(hw); + unsigned long val; + + val = clk_readl(mult->reg) >> mult->shift; + val &= GENMASK(mult->width - 1, 0); + + if (!val && mult->flags & CLK_MULTIPLIER_ZERO_BYPASS) + val = 1; + + return parent_rate * val; +} + +static bool __is_best_rate(unsigned long rate, unsigned long new, + unsigned long best, unsigned long flags) +{ + if (flags & CLK_MULTIPLIER_ROUND_CLOSEST) + return abs(rate - new) < abs(rate - best); + + return new >= rate && new < best; +} + +static unsigned long __bestmult(struct clk_hw *hw, unsigned long rate, + unsigned long *best_parent_rate, + u8 width, unsigned long flags) +{ + unsigned long orig_parent_rate = *best_parent_rate; + unsigned long parent_rate, current_rate, best_rate = ~0; + unsigned int i, bestmult = 0; + + if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) + return rate / *best_parent_rate; + + for (i = 1; i < ((1 << width) - 1); i++) { + if (rate == orig_parent_rate * i) { + /* + * This is the best case for us if we have a + * perfect match without changing the parent + * rate. + */ + *best_parent_rate = orig_parent_rate; + return i; + } + + parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw), + rate / i); + current_rate = parent_rate * i; + + if (__is_best_rate(rate, current_rate, best_rate, flags)) { + bestmult = i; + best_rate = current_rate; + *best_parent_rate = parent_rate; + } + } + + return bestmult; +} + +static long clk_multiplier_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + struct clk_multiplier *mult = to_clk_multiplier(hw); + unsigned long factor = __bestmult(hw, rate, parent_rate, + mult->width, mult->flags); + + return *parent_rate * factor; +} + +static int clk_multiplier_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_multiplier *mult = to_clk_multiplier(hw); + unsigned long factor = __get_mult(mult, rate, parent_rate); + unsigned long flags = 0; + unsigned long val; + + if (mult->lock) + spin_lock_irqsave(mult->lock, flags); + else + __acquire(mult->lock); + + val = clk_readl(mult->reg); + val &= ~GENMASK(mult->width + mult->shift - 1, mult->shift); + val |= factor << mult->shift; + clk_writel(val, mult->reg); + + if (mult->lock) + spin_unlock_irqrestore(mult->lock, flags); + else + __release(mult->lock); + + return 0; +} + +const struct clk_ops clk_multiplier_ops = { + .recalc_rate = clk_multiplier_recalc_rate, + .round_rate = clk_multiplier_round_rate, + .set_rate = clk_multiplier_set_rate, +}; +EXPORT_SYMBOL_GPL(clk_multiplier_ops); |