121 lines
2.3 KiB
C
121 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
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*/
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#include <linux/clk-provider.h>
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#include <linux/clkdev.h>
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#include <linux/clk/at91_pmc.h>
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#include <linux/of.h>
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#include <linux/mfd/syscon.h>
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#include <linux/regmap.h>
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#include "pmc.h"
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#define SYSTEM_MAX_ID 31
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#define SYSTEM_MAX_NAME_SZ 32
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#define to_clk_system(hw) container_of(hw, struct clk_system, hw)
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struct clk_system {
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struct clk_hw hw;
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struct regmap *regmap;
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u8 id;
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};
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static inline int is_pck(int id)
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{
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return (id >= 8) && (id <= 15);
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}
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static inline bool clk_system_ready(struct regmap *regmap, int id)
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{
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unsigned int status;
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regmap_read(regmap, AT91_PMC_SR, &status);
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return !!(status & (1 << id));
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}
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static int clk_system_prepare(struct clk_hw *hw)
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{
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struct clk_system *sys = to_clk_system(hw);
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regmap_write(sys->regmap, AT91_PMC_SCER, 1 << sys->id);
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if (!is_pck(sys->id))
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return 0;
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while (!clk_system_ready(sys->regmap, sys->id))
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cpu_relax();
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return 0;
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}
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static void clk_system_unprepare(struct clk_hw *hw)
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{
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struct clk_system *sys = to_clk_system(hw);
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regmap_write(sys->regmap, AT91_PMC_SCDR, 1 << sys->id);
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}
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static int clk_system_is_prepared(struct clk_hw *hw)
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{
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struct clk_system *sys = to_clk_system(hw);
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unsigned int status;
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regmap_read(sys->regmap, AT91_PMC_SCSR, &status);
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if (!(status & (1 << sys->id)))
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return 0;
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if (!is_pck(sys->id))
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return 1;
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regmap_read(sys->regmap, AT91_PMC_SR, &status);
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return !!(status & (1 << sys->id));
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}
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static const struct clk_ops system_ops = {
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.prepare = clk_system_prepare,
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.unprepare = clk_system_unprepare,
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.is_prepared = clk_system_is_prepared,
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};
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struct clk_hw * __init
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at91_clk_register_system(struct regmap *regmap, const char *name,
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const char *parent_name, u8 id)
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{
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struct clk_system *sys;
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struct clk_hw *hw;
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struct clk_init_data init;
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int ret;
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if (!parent_name || id > SYSTEM_MAX_ID)
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return ERR_PTR(-EINVAL);
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sys = kzalloc(sizeof(*sys), GFP_KERNEL);
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if (!sys)
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return ERR_PTR(-ENOMEM);
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init.name = name;
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init.ops = &system_ops;
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init.parent_names = &parent_name;
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init.num_parents = 1;
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init.flags = CLK_SET_RATE_PARENT;
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sys->id = id;
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sys->hw.init = &init;
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sys->regmap = regmap;
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hw = &sys->hw;
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ret = clk_hw_register(NULL, &sys->hw);
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if (ret) {
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kfree(sys);
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hw = ERR_PTR(ret);
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}
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return hw;
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}
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