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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright 2018 NXP
* Dong Aisheng <aisheng.dong@nxp.com>
*/
#include <linux/bits.h>
#include <linux/clk-provider.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/units.h>
#include "clk-scu.h"
static DEFINE_SPINLOCK(imx_lpcg_scu_lock);
#define CLK_GATE_SCU_LPCG_MASK 0x3
#define CLK_GATE_SCU_LPCG_HW_SEL BIT(0)
#define CLK_GATE_SCU_LPCG_SW_SEL BIT(1)
/*
* struct clk_lpcg_scu - Description of LPCG clock
*
* @hw: clk_hw of this LPCG
* @reg: register of this LPCG clock
* @bit_idx: bit index of this LPCG clock
* @hw_gate: HW auto gate enable
*
* This structure describes one LPCG clock
*/
struct clk_lpcg_scu {
struct clk_hw hw;
void __iomem *reg;
u8 bit_idx;
bool hw_gate;
/* for state save&restore */
u32 state;
};
#define to_clk_lpcg_scu(_hw) container_of(_hw, struct clk_lpcg_scu, hw)
/* e10858 -LPCG clock gating register synchronization errata */
static void lpcg_e10858_writel(unsigned long rate, void __iomem *reg, u32 val)
{
writel(val, reg);
if (rate >= 24 * HZ_PER_MHZ || rate == 0) {
/*
* The time taken to access the LPCG registers from the AP core
* through the interconnect is longer than the minimum delay
* of 4 clock cycles required by the errata.
* Adding a readl will provide sufficient delay to prevent
* back-to-back writes.
*/
readl(reg);
} else {
/*
* For clocks running below 24MHz, wait a minimum of
* 4 clock cycles.
*/
ndelay(4 * (DIV_ROUND_UP(1000 * HZ_PER_MHZ, rate)));
}
}
static int clk_lpcg_scu_enable(struct clk_hw *hw)
{
struct clk_lpcg_scu *clk = to_clk_lpcg_scu(hw);
unsigned long flags;
u32 reg, val;
spin_lock_irqsave(&imx_lpcg_scu_lock, flags);
reg = readl_relaxed(clk->reg);
reg &= ~(CLK_GATE_SCU_LPCG_MASK << clk->bit_idx);
val = CLK_GATE_SCU_LPCG_SW_SEL;
if (clk->hw_gate)
val |= CLK_GATE_SCU_LPCG_HW_SEL;
reg |= val << clk->bit_idx;
lpcg_e10858_writel(clk_hw_get_rate(hw), clk->reg, reg);
spin_unlock_irqrestore(&imx_lpcg_scu_lock, flags);
return 0;
}
static void clk_lpcg_scu_disable(struct clk_hw *hw)
{
struct clk_lpcg_scu *clk = to_clk_lpcg_scu(hw);
unsigned long flags;
u32 reg;
spin_lock_irqsave(&imx_lpcg_scu_lock, flags);
reg = readl_relaxed(clk->reg);
reg &= ~(CLK_GATE_SCU_LPCG_MASK << clk->bit_idx);
lpcg_e10858_writel(clk_hw_get_rate(hw), clk->reg, reg);
spin_unlock_irqrestore(&imx_lpcg_scu_lock, flags);
}
static const struct clk_ops clk_lpcg_scu_ops = {
.enable = clk_lpcg_scu_enable,
.disable = clk_lpcg_scu_disable,
};
struct clk_hw *__imx_clk_lpcg_scu(struct device *dev, const char *name,
const char *parent_name, unsigned long flags,
void __iomem *reg, u8 bit_idx, bool hw_gate)
{
struct clk_lpcg_scu *clk;
struct clk_init_data init;
struct clk_hw *hw;
int ret;
clk = kzalloc(sizeof(*clk), GFP_KERNEL);
if (!clk)
return ERR_PTR(-ENOMEM);
clk->reg = reg;
clk->bit_idx = bit_idx;
clk->hw_gate = hw_gate;
init.name = name;
init.ops = &clk_lpcg_scu_ops;
init.flags = CLK_SET_RATE_PARENT | flags;
init.parent_names = parent_name ? &parent_name : NULL;
init.num_parents = parent_name ? 1 : 0;
clk->hw.init = &init;
hw = &clk->hw;
ret = clk_hw_register(dev, hw);
if (ret) {
kfree(clk);
hw = ERR_PTR(ret);
return hw;
}
if (dev)
dev_set_drvdata(dev, clk);
return hw;
}
void imx_clk_lpcg_scu_unregister(struct clk_hw *hw)
{
struct clk_lpcg_scu *clk = to_clk_lpcg_scu(hw);
clk_hw_unregister(&clk->hw);
kfree(clk);
}
static int __maybe_unused imx_clk_lpcg_scu_suspend(struct device *dev)
{
struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
if (!strncmp("hdmi_lpcg", clk_hw_get_name(&clk->hw), strlen("hdmi_lpcg")))
return 0;
clk->state = readl_relaxed(clk->reg);
dev_dbg(dev, "save lpcg state 0x%x\n", clk->state);
return 0;
}
static int __maybe_unused imx_clk_lpcg_scu_resume(struct device *dev)
{
struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
if (!strncmp("hdmi_lpcg", clk_hw_get_name(&clk->hw), strlen("hdmi_lpcg")))
return 0;
writel(clk->state, clk->reg);
lpcg_e10858_writel(0, clk->reg, clk->state);
dev_dbg(dev, "restore lpcg state 0x%x\n", clk->state);
return 0;
}
const struct dev_pm_ops imx_clk_lpcg_scu_pm_ops = {
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_clk_lpcg_scu_suspend,
imx_clk_lpcg_scu_resume)
};
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