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https://github.com/AsahiLinux/u-boot
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16502bfa7c
Add clk-system driver compatible with common clock framework. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
112 lines
2.2 KiB
C
112 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* System clock support for AT91 architectures.
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*
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* Copyright (C) Microchip Technology Inc. and its subsidiaries
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*
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* Author: Claudiu Beznea <claudiu.beznea@microchip.com>
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*
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* Based on drivers/clk/at91/clk-system.c from Linux.
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*/
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#include <asm/processor.h>
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#include <common.h>
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#include <clk-uclass.h>
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#include <dm.h>
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#include <linux/io.h>
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#include <linux/clk-provider.h>
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#include <linux/clk/at91_pmc.h>
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#include "pmc.h"
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#define UBOOT_DM_CLK_AT91_SYSTEM "at91-system-clk"
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#define SYSTEM_MAX_ID 31
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struct clk_system {
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void __iomem *base;
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struct clk clk;
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u8 id;
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};
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#define to_clk_system(_c) container_of(_c, struct clk_system, clk)
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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(void __iomem *base, int id)
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{
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unsigned int status;
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pmc_read(base, AT91_PMC_SR, &status);
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return !!(status & (1 << id));
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}
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static int clk_system_enable(struct clk *clk)
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{
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struct clk_system *sys = to_clk_system(clk);
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pmc_write(sys->base, 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->base, sys->id)) {
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debug("waiting for pck%u\n", sys->id);
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cpu_relax();
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}
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return 0;
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}
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static int clk_system_disable(struct clk *clk)
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{
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struct clk_system *sys = to_clk_system(clk);
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pmc_write(sys->base, AT91_PMC_SCDR, 1 << sys->id);
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return 0;
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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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.get_rate = clk_generic_get_rate,
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};
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struct clk *at91_clk_register_system(void __iomem *base, 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;
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int ret;
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if (!base || !name || !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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sys->id = id;
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sys->base = base;
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clk = &sys->clk;
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clk->flags = CLK_GET_RATE_NOCACHE;
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ret = clk_register(clk, UBOOT_DM_CLK_AT91_SYSTEM, name, parent_name);
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if (ret) {
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kfree(sys);
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clk = ERR_PTR(ret);
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}
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return clk;
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}
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U_BOOT_DRIVER(at91_system_clk) = {
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.name = UBOOT_DM_CLK_AT91_SYSTEM,
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.id = UCLASS_CLK,
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.ops = &system_ops,
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.flags = DM_FLAG_PRE_RELOC,
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};
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