clk-gate.c
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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
* Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
* Copyright 2019 NXP
*
* Gated clock implementation
*/
#include <common.h>
#include <asm/io.h>
#include <malloc.h>
#include <clk-uclass.h>
#include <dm/device.h>
#include <dm/devres.h>
#include <linux/clk-provider.h>
#include <clk.h>
#include "clk.h"
#include <linux/err.h>
#define UBOOT_DM_CLK_GATE "clk_gate"
/**
* DOC: basic gatable clock which can gate and ungate it's output
*
* Traits of this clock:
* prepare - clk_(un)prepare only ensures parent is (un)prepared
* enable - clk_enable and clk_disable are functional & control gating
* rate - inherits rate from parent. No clk_set_rate support
* parent - fixed parent. No clk_set_parent support
*/
/*
* It works on following logic:
*
* For enabling clock, enable = 1
* set2dis = 1 -> clear bit -> set = 0
* set2dis = 0 -> set bit -> set = 1
*
* For disabling clock, enable = 0
* set2dis = 1 -> set bit -> set = 1
* set2dis = 0 -> clear bit -> set = 0
*
* So, result is always: enable xor set2dis.
*/
static void clk_gate_endisable(struct clk *clk, int enable)
{
struct clk_gate *gate = to_clk_gate(clk_dev_binded(clk) ?
dev_get_clk_ptr(clk->dev) : clk);
int set = gate->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
u32 reg;
set ^= enable;
if (gate->flags & CLK_GATE_HIWORD_MASK) {
reg = BIT(gate->bit_idx + 16);
if (set)
reg |= BIT(gate->bit_idx);
} else {
#if CONFIG_IS_ENABLED(SANDBOX_CLK_CCF)
reg = gate->io_gate_val;
#else
reg = readl(gate->reg);
#endif
if (set)
reg |= BIT(gate->bit_idx);
else
reg &= ~BIT(gate->bit_idx);
}
writel(reg, gate->reg);
}
static int clk_gate_enable(struct clk *clk)
{
clk_gate_endisable(clk, 1);
return 0;
}
static int clk_gate_disable(struct clk *clk)
{
clk_gate_endisable(clk, 0);
return 0;
}
int clk_gate_is_enabled(struct clk *clk)
{
struct clk_gate *gate = to_clk_gate(clk_dev_binded(clk) ?
dev_get_clk_ptr(clk->dev) : clk);
u32 reg;
#if CONFIG_IS_ENABLED(SANDBOX_CLK_CCF)
reg = gate->io_gate_val;
#else
reg = readl(gate->reg);
#endif
/* if a set bit disables this clk, flip it before masking */
if (gate->flags & CLK_GATE_SET_TO_DISABLE)
reg ^= BIT(gate->bit_idx);
reg &= BIT(gate->bit_idx);
return reg ? 1 : 0;
}
const struct clk_ops clk_gate_ops = {
.enable = clk_gate_enable,
.disable = clk_gate_disable,
.get_rate = clk_generic_get_rate,
};
struct clk *clk_register_gate(struct device *dev, const char *name,
const char *parent_name, unsigned long flags,
void __iomem *reg, u8 bit_idx,
u8 clk_gate_flags, spinlock_t *lock)
{
struct clk_gate *gate;
struct clk *clk;
int ret;
if (clk_gate_flags & CLK_GATE_HIWORD_MASK) {
if (bit_idx > 15) {
pr_err("gate bit exceeds LOWORD field\n");
return ERR_PTR(-EINVAL);
}
}
/* allocate the gate */
gate = kzalloc(sizeof(*gate), GFP_KERNEL);
if (!gate)
return ERR_PTR(-ENOMEM);
/* struct clk_gate assignments */
gate->reg = reg;
gate->bit_idx = bit_idx;
gate->flags = clk_gate_flags;
#if CONFIG_IS_ENABLED(SANDBOX_CLK_CCF)
gate->io_gate_val = *(u32 *)reg;
#endif
clk = &gate->clk;
ret = clk_register(clk, UBOOT_DM_CLK_GATE, name, parent_name);
if (ret) {
kfree(gate);
return ERR_PTR(ret);
}
return clk;
}
U_BOOT_DRIVER(clk_gate) = {
.name = UBOOT_DM_CLK_GATE,
.id = UCLASS_CLK,
.ops = &clk_gate_ops,
.flags = DM_FLAG_PRE_RELOC,
};