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This patch adds new at91 system clock implementation using common clk framework. Some peripherals need to enable a "system" clock in order to work properly. Each system clock is given an id based on the bit position in SCER/SCDR registers. Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com> Acked-by: Mike Turquette <mturquette@linaro.org> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
136 lines
3.1 KiB
C
136 lines
3.1 KiB
C
/*
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* Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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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/of_address.h>
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#include <linux/io.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 at91_pmc *pmc;
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u8 id;
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};
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static int clk_system_enable(struct clk_hw *hw)
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{
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struct clk_system *sys = to_clk_system(hw);
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struct at91_pmc *pmc = sys->pmc;
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pmc_write(pmc, AT91_PMC_SCER, 1 << sys->id);
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return 0;
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}
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static void clk_system_disable(struct clk_hw *hw)
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{
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struct clk_system *sys = to_clk_system(hw);
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struct at91_pmc *pmc = sys->pmc;
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pmc_write(pmc, AT91_PMC_SCDR, 1 << sys->id);
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}
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static int clk_system_is_enabled(struct clk_hw *hw)
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{
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struct clk_system *sys = to_clk_system(hw);
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struct at91_pmc *pmc = sys->pmc;
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return !!(pmc_read(pmc, AT91_PMC_SCSR) & (1 << sys->id));
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}
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static const struct clk_ops system_ops = {
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.enable = clk_system_enable,
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.disable = clk_system_disable,
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.is_enabled = clk_system_is_enabled,
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};
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static struct clk * __init
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at91_clk_register_system(struct at91_pmc *pmc, 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 *clk = NULL;
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struct clk_init_data init;
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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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/*
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* CLK_IGNORE_UNUSED is used to avoid ddrck switch off.
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* TODO : we should implement a driver supporting at91 ddr controller
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* (see drivers/memory) which would request and enable the ddrck clock.
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* When this is done we will be able to remove CLK_IGNORE_UNUSED flag.
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*/
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init.flags = CLK_IGNORE_UNUSED;
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sys->id = id;
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sys->hw.init = &init;
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sys->pmc = pmc;
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clk = clk_register(NULL, &sys->hw);
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if (IS_ERR(clk))
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kfree(sys);
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return clk;
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}
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static void __init
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of_at91_clk_sys_setup(struct device_node *np, struct at91_pmc *pmc)
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{
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int num;
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u32 id;
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struct clk *clk;
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const char *name;
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struct device_node *sysclknp;
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const char *parent_name;
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num = of_get_child_count(np);
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if (num > (SYSTEM_MAX_ID + 1))
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return;
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for_each_child_of_node(np, sysclknp) {
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if (of_property_read_u32(sysclknp, "reg", &id))
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continue;
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if (of_property_read_string(np, "clock-output-names", &name))
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name = sysclknp->name;
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parent_name = of_clk_get_parent_name(sysclknp, 0);
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clk = at91_clk_register_system(pmc, name, parent_name, id);
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if (IS_ERR(clk))
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continue;
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of_clk_add_provider(sysclknp, of_clk_src_simple_get, clk);
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}
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}
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void __init of_at91rm9200_clk_sys_setup(struct device_node *np,
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struct at91_pmc *pmc)
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{
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of_at91_clk_sys_setup(np, pmc);
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}
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