root/drivers/clk/keystone/syscon-clk.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020 Texas Instruments Incorporated - https://www.ti.com/
 */

#include <linux/clk-provider.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>

struct ti_syscon_gate_clk_priv {
        struct clk_hw hw;
        struct regmap *regmap;
        u32 reg;
        u32 idx;
};

struct ti_syscon_gate_clk_data {
        char *name;
        u32 offset;
        u32 bit_idx;
};

static struct
ti_syscon_gate_clk_priv *to_ti_syscon_gate_clk_priv(struct clk_hw *hw)
{
        return container_of(hw, struct ti_syscon_gate_clk_priv, hw);
}

static int ti_syscon_gate_clk_enable(struct clk_hw *hw)
{
        struct ti_syscon_gate_clk_priv *priv = to_ti_syscon_gate_clk_priv(hw);

        return regmap_write_bits(priv->regmap, priv->reg, priv->idx,
                                 priv->idx);
}

static void ti_syscon_gate_clk_disable(struct clk_hw *hw)
{
        struct ti_syscon_gate_clk_priv *priv = to_ti_syscon_gate_clk_priv(hw);

        regmap_write_bits(priv->regmap, priv->reg, priv->idx, 0);
}

static int ti_syscon_gate_clk_is_enabled(struct clk_hw *hw)
{
        unsigned int val;
        struct ti_syscon_gate_clk_priv *priv = to_ti_syscon_gate_clk_priv(hw);

        regmap_read(priv->regmap, priv->reg, &val);

        return !!(val & priv->idx);
}

static const struct clk_ops ti_syscon_gate_clk_ops = {
        .enable         = ti_syscon_gate_clk_enable,
        .disable        = ti_syscon_gate_clk_disable,
        .is_enabled     = ti_syscon_gate_clk_is_enabled,
};

static struct clk_hw
*ti_syscon_gate_clk_register(struct device *dev, struct regmap *regmap,
                             const char *parent_name,
                             const struct ti_syscon_gate_clk_data *data)
{
        struct ti_syscon_gate_clk_priv *priv;
        struct clk_init_data init;
        char *name = NULL;
        int ret;

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return ERR_PTR(-ENOMEM);

        init.ops = &ti_syscon_gate_clk_ops;
        if (parent_name) {
                name = kasprintf(GFP_KERNEL, "%s:%s", data->name, parent_name);
                init.name = name;
                init.parent_names = &parent_name;
                init.num_parents = 1;
                init.flags = CLK_SET_RATE_PARENT;
        } else {
                init.name = data->name;
                init.parent_names = NULL;
                init.num_parents = 0;
                init.flags = 0;
        }

        priv->regmap = regmap;
        priv->reg = data->offset;
        priv->idx = BIT(data->bit_idx);
        priv->hw.init = &init;

        ret = devm_clk_hw_register(dev, &priv->hw);

        if (name)
                kfree(init.name);

        if (ret)
                return ERR_PTR(ret);

        return &priv->hw;
}

static const struct regmap_config ti_syscon_regmap_cfg = {
        .reg_bits = 32,
        .val_bits = 32,
        .reg_stride = 4,
};

static int ti_syscon_gate_clk_probe(struct platform_device *pdev)
{
        const struct ti_syscon_gate_clk_data *data, *p;
        struct clk_hw_onecell_data *hw_data;
        struct device *dev = &pdev->dev;
        int num_clks, num_parents, i;
        const char *parent_name;
        struct regmap *regmap;
        void __iomem *base;

        data = device_get_match_data(dev);
        if (!data)
                return -EINVAL;

        base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(base))
                return PTR_ERR(base);

        regmap = devm_regmap_init_mmio(dev, base, &ti_syscon_regmap_cfg);
        if (IS_ERR(regmap))
                return dev_err_probe(dev, PTR_ERR(regmap),
                                     "failed to get regmap\n");

        num_clks = 0;
        for (p = data; p->name; p++)
                num_clks++;

        num_parents = of_clk_get_parent_count(dev->of_node);
        if (of_device_is_compatible(dev->of_node, "ti,am62-audio-refclk") &&
            num_parents == 0) {
                return dev_err_probe(dev, -EINVAL,
                                     "must specify a parent clock\n");
        }

        hw_data = devm_kzalloc(dev, struct_size(hw_data, hws, num_clks),
                               GFP_KERNEL);
        if (!hw_data)
                return -ENOMEM;

        hw_data->num = num_clks;

        parent_name = of_clk_get_parent_name(dev->of_node, 0);
        for (i = 0; i < num_clks; i++) {
                hw_data->hws[i] = ti_syscon_gate_clk_register(dev, regmap,
                                                              parent_name,
                                                              &data[i]);
                if (IS_ERR(hw_data->hws[i]))
                        dev_warn(dev, "failed to register %s\n",
                                 data[i].name);
        }

        if (num_clks == 1)
                return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
                                                   hw_data->hws[0]);
        return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, hw_data);
}

#define TI_SYSCON_CLK_GATE(_name, _offset, _bit_idx)    \
        {                                               \
                .name = _name,                          \
                .offset = (_offset),                    \
                .bit_idx = (_bit_idx),                  \
        }

static const struct ti_syscon_gate_clk_data am654_clk_data[] = {
        TI_SYSCON_CLK_GATE("ehrpwm_tbclk0", 0x0, 0),
        TI_SYSCON_CLK_GATE("ehrpwm_tbclk1", 0x4, 0),
        TI_SYSCON_CLK_GATE("ehrpwm_tbclk2", 0x8, 0),
        TI_SYSCON_CLK_GATE("ehrpwm_tbclk3", 0xc, 0),
        TI_SYSCON_CLK_GATE("ehrpwm_tbclk4", 0x10, 0),
        TI_SYSCON_CLK_GATE("ehrpwm_tbclk5", 0x14, 0),
        { /* Sentinel */ },
};

static const struct ti_syscon_gate_clk_data am64_clk_data[] = {
        TI_SYSCON_CLK_GATE("epwm_tbclk0", 0x0, 0),
        TI_SYSCON_CLK_GATE("epwm_tbclk1", 0x0, 1),
        TI_SYSCON_CLK_GATE("epwm_tbclk2", 0x0, 2),
        TI_SYSCON_CLK_GATE("epwm_tbclk3", 0x0, 3),
        TI_SYSCON_CLK_GATE("epwm_tbclk4", 0x0, 4),
        TI_SYSCON_CLK_GATE("epwm_tbclk5", 0x0, 5),
        TI_SYSCON_CLK_GATE("epwm_tbclk6", 0x0, 6),
        TI_SYSCON_CLK_GATE("epwm_tbclk7", 0x0, 7),
        TI_SYSCON_CLK_GATE("epwm_tbclk8", 0x0, 8),
        { /* Sentinel */ },
};

static const struct ti_syscon_gate_clk_data am62_clk_data[] = {
        TI_SYSCON_CLK_GATE("epwm_tbclk0", 0x0, 0),
        TI_SYSCON_CLK_GATE("epwm_tbclk1", 0x0, 1),
        TI_SYSCON_CLK_GATE("epwm_tbclk2", 0x0, 2),
        { /* Sentinel */ },
};

static const struct ti_syscon_gate_clk_data am62_audio_clk_data[] = {
        TI_SYSCON_CLK_GATE("audio_refclk", 0x0, 15),
        { /* Sentinel */ },
};

static const struct of_device_id ti_syscon_gate_clk_ids[] = {
        {
                .compatible = "ti,am654-ehrpwm-tbclk",
                .data = &am654_clk_data,
        },
        {
                .compatible = "ti,am64-epwm-tbclk",
                .data = &am64_clk_data,
        },
        {
                .compatible = "ti,am62-epwm-tbclk",
                .data = &am62_clk_data,
        },
        {
                .compatible = "ti,am62-audio-refclk",
                .data = &am62_audio_clk_data,
        },
        { }
};
MODULE_DEVICE_TABLE(of, ti_syscon_gate_clk_ids);

static struct platform_driver ti_syscon_gate_clk_driver = {
        .probe = ti_syscon_gate_clk_probe,
        .driver = {
                .name = "ti-syscon-gate-clk",
                .of_match_table = ti_syscon_gate_clk_ids,
        },
};
module_platform_driver(ti_syscon_gate_clk_driver);

MODULE_AUTHOR("Vignesh Raghavendra <vigneshr@ti.com>");
MODULE_DESCRIPTION("Syscon backed gate-clock driver");
MODULE_LICENSE("GPL");