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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-26 12:42:29 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-26 12:42:29 -0700 |
commit | 27953437059c64d14086196eb96f43c78caa9db3 (patch) | |
tree | 0cfd5fb21262a6db3de0c64462847b4c0c43e9df /drivers/clk/mxs/clk-frac.c | |
parent | 2c757fd5d1a92086f225a75a8fac7cab242d11b0 (diff) | |
parent | 3c0dec5f58b3c7b3627715126d1bf9b030a076f0 (diff) | |
download | kernel_goldelico_gta04-27953437059c64d14086196eb96f43c78caa9db3.zip kernel_goldelico_gta04-27953437059c64d14086196eb96f43c78caa9db3.tar.gz kernel_goldelico_gta04-27953437059c64d14086196eb96f43c78caa9db3.tar.bz2 |
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/mxs/clk-frac.c')
-rw-r--r-- | drivers/clk/mxs/clk-frac.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/drivers/clk/mxs/clk-frac.c b/drivers/clk/mxs/clk-frac.c new file mode 100644 index 0000000..e6aa6b5 --- /dev/null +++ b/drivers/clk/mxs/clk-frac.c @@ -0,0 +1,139 @@ +/* + * Copyright 2012 Freescale Semiconductor, Inc. + * + * The code contained herein is licensed under the GNU General Public + * License. You may obtain a copy of the GNU General Public License + * Version 2 or later at the following locations: + * + * http://www.opensource.org/licenses/gpl-license.html + * http://www.gnu.org/copyleft/gpl.html + */ + +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/slab.h> +#include "clk.h" + +/** + * struct clk_frac - mxs fractional divider clock + * @hw: clk_hw for the fractional divider clock + * @reg: register address + * @shift: the divider bit shift + * @width: the divider bit width + * @busy: busy bit shift + * + * The clock is an adjustable fractional divider with a busy bit to wait + * when the divider is adjusted. + */ +struct clk_frac { + struct clk_hw hw; + void __iomem *reg; + u8 shift; + u8 width; + u8 busy; +}; + +#define to_clk_frac(_hw) container_of(_hw, struct clk_frac, hw) + +static unsigned long clk_frac_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_frac *frac = to_clk_frac(hw); + u32 div; + + div = readl_relaxed(frac->reg) >> frac->shift; + div &= (1 << frac->width) - 1; + + return (parent_rate >> frac->width) * div; +} + +static long clk_frac_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + struct clk_frac *frac = to_clk_frac(hw); + unsigned long parent_rate = *prate; + u32 div; + u64 tmp; + + if (rate > parent_rate) + return -EINVAL; + + tmp = rate; + tmp <<= frac->width; + do_div(tmp, parent_rate); + div = tmp; + + if (!div) + return -EINVAL; + + return (parent_rate >> frac->width) * div; +} + +static int clk_frac_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_frac *frac = to_clk_frac(hw); + unsigned long flags; + u32 div, val; + u64 tmp; + + if (rate > parent_rate) + return -EINVAL; + + tmp = rate; + tmp <<= frac->width; + do_div(tmp, parent_rate); + div = tmp; + + if (!div) + return -EINVAL; + + spin_lock_irqsave(&mxs_lock, flags); + + val = readl_relaxed(frac->reg); + val &= ~(((1 << frac->width) - 1) << frac->shift); + val |= div << frac->shift; + writel_relaxed(val, frac->reg); + + spin_unlock_irqrestore(&mxs_lock, flags); + + return mxs_clk_wait(frac->reg, frac->busy); +} + +static 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 *mxs_clk_frac(const char *name, const char *parent_name, + void __iomem *reg, u8 shift, u8 width, u8 busy) +{ + struct clk_frac *frac; + struct clk *clk; + struct clk_init_data init; + + frac = kzalloc(sizeof(*frac), GFP_KERNEL); + if (!frac) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &clk_frac_ops; + init.flags = CLK_SET_RATE_PARENT; + init.parent_names = (parent_name ? &parent_name: NULL); + init.num_parents = (parent_name ? 1 : 0); + + frac->reg = reg; + frac->shift = shift; + frac->width = width; + frac->busy = busy; + frac->hw.init = &init; + + clk = clk_register(NULL, &frac->hw); + if (IS_ERR(clk)) + kfree(frac); + + return clk; +} |