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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2025 Collabora Ltd.
* Author: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
*
* Certain clocks on Rockchip are "gated" behind an additional register bit
* write in a GRF register, such as the SAI MCLKs on RK3576. This code
* implements a clock driver for these types of gates, based on regmaps.
*/
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include "clk.h"
struct rockchip_gate_grf {
struct clk_hw hw;
struct regmap *regmap;
unsigned int reg;
unsigned int shift;
u8 flags;
};
#define to_gate_grf(_hw) container_of(_hw, struct rockchip_gate_grf, hw)
static int rockchip_gate_grf_enable(struct clk_hw *hw)
{
struct rockchip_gate_grf *gate = to_gate_grf(hw);
u32 val = !(gate->flags & CLK_GATE_SET_TO_DISABLE) ? BIT(gate->shift) : 0;
u32 hiword = ((gate->flags & CLK_GATE_HIWORD_MASK) ? 1 : 0) << (gate->shift + 16);
int ret;
ret = regmap_update_bits(gate->regmap, gate->reg,
hiword | BIT(gate->shift), hiword | val);
return ret;
}
static void rockchip_gate_grf_disable(struct clk_hw *hw)
{
struct rockchip_gate_grf *gate = to_gate_grf(hw);
u32 val = !(gate->flags & CLK_GATE_SET_TO_DISABLE) ? 0 : BIT(gate->shift);
u32 hiword = ((gate->flags & CLK_GATE_HIWORD_MASK) ? 1 : 0) << (gate->shift + 16);
regmap_update_bits(gate->regmap, gate->reg,
hiword | BIT(gate->shift), hiword | val);
}
static int rockchip_gate_grf_is_enabled(struct clk_hw *hw)
{
struct rockchip_gate_grf *gate = to_gate_grf(hw);
bool invert = !!(gate->flags & CLK_GATE_SET_TO_DISABLE);
int ret;
ret = regmap_test_bits(gate->regmap, gate->reg, BIT(gate->shift));
if (ret < 0)
ret = 0;
return invert ? 1 - ret : ret;
}
static const struct clk_ops rockchip_gate_grf_ops = {
.enable = rockchip_gate_grf_enable,
.disable = rockchip_gate_grf_disable,
.is_enabled = rockchip_gate_grf_is_enabled,
};
struct clk *rockchip_clk_register_gate_grf(const char *name,
const char *parent_name, unsigned long flags,
struct regmap *regmap, unsigned int reg, unsigned int shift,
u8 gate_flags)
{
struct rockchip_gate_grf *gate;
struct clk_init_data init;
struct clk *clk;
if (IS_ERR(regmap)) {
pr_err("%s: regmap not available\n", __func__);
return ERR_PTR(-EOPNOTSUPP);
}
gate = kzalloc(sizeof(*gate), GFP_KERNEL);
if (!gate)
return ERR_PTR(-ENOMEM);
init.name = name;
init.flags = flags;
init.num_parents = parent_name ? 1 : 0;
init.parent_names = parent_name ? &parent_name : NULL;
init.ops = &rockchip_gate_grf_ops;
gate->hw.init = &init;
gate->regmap = regmap;
gate->reg = reg;
gate->shift = shift;
gate->flags = gate_flags;
clk = clk_register(NULL, &gate->hw);
if (IS_ERR(clk))
kfree(gate);
return clk;
}
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