linux/drivers/clk/imx/clk-lpcg-scu.c
Dong Aisheng d5f1e6a2bb clk: imx: imx8qxp-lpcg: add parsing clocks from device tree
One LPCG controller supports up to 8 clock outputs while each of them
is fixed to 4 bits.  It supports only gating function with fixed bits.
So we can use the clk-indices to fetch the corresponding clock idx from
device tree. With this way, we can write a generic LPCG clock drivers.

This patch add that support to parse clocks from device tree.

Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Michael Turquette <mturquette@baylibre.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
2020-10-26 10:54:00 +08:00

126 lines
2.6 KiB
C

// 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/err.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/spinlock.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;
};
#define to_clk_lpcg_scu(_hw) container_of(_hw, struct clk_lpcg_scu, hw)
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;
writel(reg, clk->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);
writel(reg, clk->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(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(NULL, hw);
if (ret) {
kfree(clk);
hw = ERR_PTR(ret);
}
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);
}