diff options
author | Shawn Guo <shawn.guo@linaro.org> | 2012-04-29 00:02:34 +0800 |
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committer | Shawn Guo <shawn.guo@linaro.org> | 2012-05-09 00:02:35 +0800 |
commit | 23b5e15a2994fb0c1444f92b76f09a482f32843c (patch) | |
tree | 54695e5b39977bd1ed04dfd945c9052a85b57e0f /drivers/clk/mxs/clk-frac.c | |
parent | d48b97b403d23f6df0b990cee652bdf9a52337a3 (diff) |
clk: mxs: add mxs specific clocks
Add mxs specific clocks, pll, reference clock (PFD), integer divider
and fractional divider.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
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 00000000000..e6aa6b567d6 --- /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; +} |