diff options
Diffstat (limited to 'drivers/clk/at91/clk-system.c')
| -rw-r--r-- | drivers/clk/at91/clk-system.c | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/drivers/clk/at91/clk-system.c b/drivers/clk/at91/clk-system.c new file mode 100644 index 000000000..86a368097 --- /dev/null +++ b/drivers/clk/at91/clk-system.c @@ -0,0 +1,162 @@ +/* + * 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 SYSTEM_MAX_ID 31 + +#define SYSTEM_MAX_NAME_SZ 32 + +#define to_clk_system(hw) container_of(hw, struct clk_system, hw) +struct clk_system { + struct clk_hw hw; + struct regmap *regmap; + u8 id; +}; + +static inline int is_pck(int id) +{ + return (id >= 8) && (id <= 15); +} + +static inline bool clk_system_ready(struct regmap *regmap, int id) +{ + unsigned int status; + + regmap_read(regmap, AT91_PMC_SR, &status); + + return status & (1 << id) ? 1 : 0; +} + +static int clk_system_prepare(struct clk_hw *hw) +{ + struct clk_system *sys = to_clk_system(hw); + + regmap_write(sys->regmap, AT91_PMC_SCER, 1 << sys->id); + + if (!is_pck(sys->id)) + return 0; + + while (!clk_system_ready(sys->regmap, sys->id)) + cpu_relax(); + + return 0; +} + +static void clk_system_unprepare(struct clk_hw *hw) +{ + struct clk_system *sys = to_clk_system(hw); + + regmap_write(sys->regmap, AT91_PMC_SCDR, 1 << sys->id); +} + +static int clk_system_is_prepared(struct clk_hw *hw) +{ + struct clk_system *sys = to_clk_system(hw); + unsigned int status; + + regmap_read(sys->regmap, AT91_PMC_SCSR, &status); + + if (!(status & (1 << sys->id))) + return 0; + + if (!is_pck(sys->id)) + return 1; + + regmap_read(sys->regmap, AT91_PMC_SR, &status); + + return status & (1 << sys->id) ? 1 : 0; +} + +static const struct clk_ops system_ops = { + .prepare = clk_system_prepare, + .unprepare = clk_system_unprepare, + .is_prepared = clk_system_is_prepared, +}; + +static struct clk_hw * __init +at91_clk_register_system(struct regmap *regmap, const char *name, + const char *parent_name, u8 id) +{ + struct clk_system *sys; + struct clk_hw *hw; + struct clk_init_data init; + int ret; + + if (!parent_name || id > SYSTEM_MAX_ID) + return ERR_PTR(-EINVAL); + + sys = kzalloc(sizeof(*sys), GFP_KERNEL); + if (!sys) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &system_ops; + init.parent_names = &parent_name; + init.num_parents = 1; + init.flags = CLK_SET_RATE_PARENT; + + sys->id = id; + sys->hw.init = &init; + sys->regmap = regmap; + + hw = &sys->hw; + ret = clk_hw_register(NULL, &sys->hw); + if (ret) { + kfree(sys); + hw = ERR_PTR(ret); + } + + return hw; +} + +static void __init of_at91rm9200_clk_sys_setup(struct device_node *np) +{ + int num; + u32 id; + struct clk_hw *hw; + const char *name; + struct device_node *sysclknp; + const char *parent_name; + struct regmap *regmap; + + num = of_get_child_count(np); + if (num > (SYSTEM_MAX_ID + 1)) + return; + + regmap = syscon_node_to_regmap(of_get_parent(np)); + if (IS_ERR(regmap)) + return; + + for_each_child_of_node(np, sysclknp) { + if (of_property_read_u32(sysclknp, "reg", &id)) + continue; + + if (of_property_read_string(np, "clock-output-names", &name)) + name = sysclknp->name; + + parent_name = of_clk_get_parent_name(sysclknp, 0); + + hw = at91_clk_register_system(regmap, name, parent_name, id); + if (IS_ERR(hw)) + continue; + + of_clk_add_hw_provider(sysclknp, of_clk_hw_simple_get, hw); + } +} +CLK_OF_DECLARE(at91rm9200_clk_sys, "atmel,at91rm9200-clk-system", + of_at91rm9200_clk_sys_setup); |