diff options
Diffstat (limited to 'drivers/clk/clk-fixed-factor.c')
| -rw-r--r-- | drivers/clk/clk-fixed-factor.c | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c new file mode 100644 index 000000000000..c8c003e217ad --- /dev/null +++ b/drivers/clk/clk-fixed-factor.c @@ -0,0 +1,95 @@ +/* + * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de> + * + * 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. + * + * Standard functionality for the common clock API. + */ +#include <linux/module.h> +#include <linux/clk-provider.h> +#include <linux/slab.h> +#include <linux/err.h> + +/* + * DOC: basic fixed multiplier and divider clock that cannot gate + * + * Traits of this clock: + * prepare - clk_prepare only ensures that parents are prepared + * enable - clk_enable only ensures that parents are enabled + * rate - rate is fixed. clk->rate = parent->rate / div * mult + * parent - fixed parent. No clk_set_parent support + */ + +#define to_clk_fixed_factor(_hw) container_of(_hw, struct clk_fixed_factor, hw) + +static unsigned long clk_factor_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_fixed_factor *fix = to_clk_fixed_factor(hw); + + return parent_rate * fix->mult / fix->div; +} + +static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + struct clk_fixed_factor *fix = to_clk_fixed_factor(hw); + + if (__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT) { + unsigned long best_parent; + + best_parent = (rate / fix->mult) * fix->div; + *prate = __clk_round_rate(__clk_get_parent(hw->clk), + best_parent); + } + + return (*prate / fix->div) * fix->mult; +} + +static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + return 0; +} + +struct clk_ops clk_fixed_factor_ops = { + .round_rate = clk_factor_round_rate, + .set_rate = clk_factor_set_rate, + .recalc_rate = clk_factor_recalc_rate, +}; +EXPORT_SYMBOL_GPL(clk_fixed_factor_ops); + +struct clk *clk_register_fixed_factor(struct device *dev, const char *name, + const char *parent_name, unsigned long flags, + unsigned int mult, unsigned int div) +{ + struct clk_fixed_factor *fix; + struct clk_init_data init; + struct clk *clk; + + fix = kmalloc(sizeof(*fix), GFP_KERNEL); + if (!fix) { + pr_err("%s: could not allocate fixed factor clk\n", __func__); + return ERR_PTR(-ENOMEM); + } + + /* struct clk_fixed_factor assignments */ + fix->mult = mult; + fix->div = div; + fix->hw.init = &init; + + init.name = name; + init.ops = &clk_fixed_factor_ops; + init.flags = flags; + init.parent_names = &parent_name; + init.num_parents = 1; + + clk = clk_register(dev, &fix->hw); + + if (IS_ERR(clk)) + kfree(fix); + + return clk; +} |