| /* |
| * Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| */ |
| |
| #include <linux/clk-provider.h> |
| #include <linux/clkdev.h> |
| #include <linux/clk/at91_pmc.h> |
| #include <linux/of.h> |
| #include <linux/mfd/syscon.h> |
| #include <linux/regmap.h> |
| |
| #include "pmc.h" |
| |
| #define MASTER_PRES_MASK 0x7 |
| #define MASTER_PRES_MAX MASTER_PRES_MASK |
| #define MASTER_DIV_SHIFT 8 |
| #define MASTER_DIV_MASK 0x3 |
| |
| #define to_clk_master(hw) container_of(hw, struct clk_master, hw) |
| |
| struct clk_master { |
| struct clk_hw hw; |
| struct regmap *regmap; |
| const struct clk_master_layout *layout; |
| const struct clk_master_characteristics *characteristics; |
| }; |
| |
| static inline bool clk_master_ready(struct regmap *regmap) |
| { |
| unsigned int status; |
| |
| regmap_read(regmap, AT91_PMC_SR, &status); |
| |
| return status & AT91_PMC_MCKRDY ? 1 : 0; |
| } |
| |
| static int clk_master_prepare(struct clk_hw *hw) |
| { |
| struct clk_master *master = to_clk_master(hw); |
| |
| while (!clk_master_ready(master->regmap)) |
| cpu_relax(); |
| |
| return 0; |
| } |
| |
| static int clk_master_is_prepared(struct clk_hw *hw) |
| { |
| struct clk_master *master = to_clk_master(hw); |
| |
| return clk_master_ready(master->regmap); |
| } |
| |
| static unsigned long clk_master_recalc_rate(struct clk_hw *hw, |
| unsigned long parent_rate) |
| { |
| u8 pres; |
| u8 div; |
| unsigned long rate = parent_rate; |
| struct clk_master *master = to_clk_master(hw); |
| const struct clk_master_layout *layout = master->layout; |
| const struct clk_master_characteristics *characteristics = |
| master->characteristics; |
| unsigned int mckr; |
| |
| regmap_read(master->regmap, AT91_PMC_MCKR, &mckr); |
| mckr &= layout->mask; |
| |
| pres = (mckr >> layout->pres_shift) & MASTER_PRES_MASK; |
| div = (mckr >> MASTER_DIV_SHIFT) & MASTER_DIV_MASK; |
| |
| if (characteristics->have_div3_pres && pres == MASTER_PRES_MAX) |
| rate /= 3; |
| else |
| rate >>= pres; |
| |
| rate /= characteristics->divisors[div]; |
| |
| if (rate < characteristics->output.min) |
| pr_warn("master clk is underclocked"); |
| else if (rate > characteristics->output.max) |
| pr_warn("master clk is overclocked"); |
| |
| return rate; |
| } |
| |
| static u8 clk_master_get_parent(struct clk_hw *hw) |
| { |
| struct clk_master *master = to_clk_master(hw); |
| unsigned int mckr; |
| |
| regmap_read(master->regmap, AT91_PMC_MCKR, &mckr); |
| |
| return mckr & AT91_PMC_CSS; |
| } |
| |
| static const struct clk_ops master_ops = { |
| .prepare = clk_master_prepare, |
| .is_prepared = clk_master_is_prepared, |
| .recalc_rate = clk_master_recalc_rate, |
| .get_parent = clk_master_get_parent, |
| }; |
| |
| struct clk_hw * __init |
| at91_clk_register_master(struct regmap *regmap, |
| const char *name, int num_parents, |
| const char **parent_names, |
| const struct clk_master_layout *layout, |
| const struct clk_master_characteristics *characteristics) |
| { |
| struct clk_master *master; |
| struct clk_init_data init; |
| struct clk_hw *hw; |
| int ret; |
| |
| if (!name || !num_parents || !parent_names) |
| return ERR_PTR(-EINVAL); |
| |
| master = kzalloc(sizeof(*master), GFP_KERNEL); |
| if (!master) |
| return ERR_PTR(-ENOMEM); |
| |
| init.name = name; |
| init.ops = &master_ops; |
| init.parent_names = parent_names; |
| init.num_parents = num_parents; |
| init.flags = 0; |
| |
| master->hw.init = &init; |
| master->layout = layout; |
| master->characteristics = characteristics; |
| master->regmap = regmap; |
| |
| hw = &master->hw; |
| ret = clk_hw_register(NULL, &master->hw); |
| if (ret) { |
| kfree(master); |
| hw = ERR_PTR(ret); |
| } |
| |
| return hw; |
| } |
| |
| |
| const struct clk_master_layout at91rm9200_master_layout = { |
| .mask = 0x31F, |
| .pres_shift = 2, |
| }; |
| |
| const struct clk_master_layout at91sam9x5_master_layout = { |
| .mask = 0x373, |
| .pres_shift = 4, |
| }; |