diff options
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-ref.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/mxs/clk-ref.c')
-rw-r--r-- | drivers/clk/mxs/clk-ref.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/drivers/clk/mxs/clk-ref.c b/drivers/clk/mxs/clk-ref.c new file mode 100644 index 000000000000..4adeed6c2f94 --- /dev/null +++ b/drivers/clk/mxs/clk-ref.c @@ -0,0 +1,154 @@ +/* + * 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_ref - mxs reference clock + * @hw: clk_hw for the reference clock + * @reg: register address + * @idx: the index of the reference clock within the same register + * + * The mxs reference clock sources from pll. Every 4 reference clocks share + * one register space, and @idx is used to identify them. Each reference + * clock has a gate control and a fractional * divider. The rate is calculated + * as pll rate * (18 / FRAC), where FRAC = 18 ~ 35. + */ +struct clk_ref { + struct clk_hw hw; + void __iomem *reg; + u8 idx; +}; + +#define to_clk_ref(_hw) container_of(_hw, struct clk_ref, hw) + +static int clk_ref_enable(struct clk_hw *hw) +{ + struct clk_ref *ref = to_clk_ref(hw); + + writel_relaxed(1 << ((ref->idx + 1) * 8 - 1), ref->reg + CLR); + + return 0; +} + +static void clk_ref_disable(struct clk_hw *hw) +{ + struct clk_ref *ref = to_clk_ref(hw); + + writel_relaxed(1 << ((ref->idx + 1) * 8 - 1), ref->reg + SET); +} + +static unsigned long clk_ref_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_ref *ref = to_clk_ref(hw); + u64 tmp = parent_rate; + u8 frac = (readl_relaxed(ref->reg) >> (ref->idx * 8)) & 0x3f; + + tmp *= 18; + do_div(tmp, frac); + + return tmp; +} + +static long clk_ref_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + unsigned long parent_rate = *prate; + u64 tmp = parent_rate; + u8 frac; + + tmp = tmp * 18 + rate / 2; + do_div(tmp, rate); + frac = tmp; + + if (frac < 18) + frac = 18; + else if (frac > 35) + frac = 35; + + tmp = parent_rate; + tmp *= 18; + do_div(tmp, frac); + + return tmp; +} + +static int clk_ref_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_ref *ref = to_clk_ref(hw); + unsigned long flags; + u64 tmp = parent_rate; + u32 val; + u8 frac, shift = ref->idx * 8; + + tmp = tmp * 18 + rate / 2; + do_div(tmp, rate); + frac = tmp; + + if (frac < 18) + frac = 18; + else if (frac > 35) + frac = 35; + + spin_lock_irqsave(&mxs_lock, flags); + + val = readl_relaxed(ref->reg); + val &= ~(0x3f << shift); + val |= frac << shift; + writel_relaxed(val, ref->reg); + + spin_unlock_irqrestore(&mxs_lock, flags); + + return 0; +} + +static const struct clk_ops clk_ref_ops = { + .enable = clk_ref_enable, + .disable = clk_ref_disable, + .recalc_rate = clk_ref_recalc_rate, + .round_rate = clk_ref_round_rate, + .set_rate = clk_ref_set_rate, +}; + +struct clk *mxs_clk_ref(const char *name, const char *parent_name, + void __iomem *reg, u8 idx) +{ + struct clk_ref *ref; + struct clk *clk; + struct clk_init_data init; + + ref = kzalloc(sizeof(*ref), GFP_KERNEL); + if (!ref) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &clk_ref_ops; + init.flags = 0; + init.parent_names = (parent_name ? &parent_name: NULL); + init.num_parents = (parent_name ? 1 : 0); + + ref->reg = reg; + ref->idx = idx; + ref->hw.init = &init; + + clk = clk_register(NULL, &ref->hw); + if (IS_ERR(clk)) + kfree(ref); + + return clk; +} |