root/drivers/clk/clk-lan966x.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Microchip LAN966x SoC Clock driver.
 *
 * Copyright (C) 2021 Microchip Technology, Inc. and its subsidiaries
 *
 * Author: Kavyasree Kotagiri <kavyasree.kotagiri@microchip.com>
 */

#include <linux/bitfield.h>
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define GCK_ENA         BIT(0)
#define GCK_SRC_SEL     GENMASK(9, 8)
#define GCK_PRESCALER   GENMASK(23, 16)

#define DIV_MAX         255

static const char * const lan966x_clk_names[] = {
        "qspi0", "qspi1", "qspi2", "sdmmc0",
        "pi", "mcan0", "mcan1", "flexcom0",
        "flexcom1", "flexcom2", "flexcom3",
        "flexcom4", "timer1", "usb_refclk",
};

static const char * const lan969x_clk_names[] = {
        "qspi0", "qspi2", "sdmmc0", "sdmmc1",
        "mcan0", "mcan1", "flexcom0",
        "flexcom1", "flexcom2", "flexcom3",
        "timer1", "usb_refclk",
};

struct lan966x_gck {
        struct clk_hw hw;
        void __iomem *reg;
};
#define to_lan966x_gck(hw) container_of(hw, struct lan966x_gck, hw)

static const struct clk_parent_data lan966x_gck_pdata[] = {
        { .fw_name = "cpu", },
        { .fw_name = "ddr", },
        { .fw_name = "sys", },
};

static struct clk_init_data init = {
        .parent_data = lan966x_gck_pdata,
        .num_parents = ARRAY_SIZE(lan966x_gck_pdata),
};

struct clk_gate_soc_desc {
        const char *name;
        int bit_idx;
};

static const struct clk_gate_soc_desc lan966x_clk_gate_desc[] = {
        { "uhphs", 11 },
        { "udphs", 10 },
        { "mcramc", 9 },
        { "hmatrix", 8 },
        { }
};

static const struct clk_gate_soc_desc lan969x_clk_gate_desc[] = {
        { "usb_drd", 10 },
        { "mcramc", 9 },
        { "hmatrix", 8 },
        { }
};

struct lan966x_match_data {
        char *name;
        const char * const *clk_name;
        const struct clk_gate_soc_desc *clk_gate_desc;
        u8 num_generic_clks;
        u8 num_total_clks;
};

static struct lan966x_match_data lan966x_desc = {
        .name = "lan966x",
        .clk_name = lan966x_clk_names,
        .clk_gate_desc = lan966x_clk_gate_desc,
        .num_total_clks = 18,
        .num_generic_clks = 14,
};

static struct lan966x_match_data lan969x_desc = {
        .name = "lan969x",
        .clk_name = lan969x_clk_names,
        .clk_gate_desc = lan969x_clk_gate_desc,
        .num_total_clks = 15,
        .num_generic_clks = 12,
};

static DEFINE_SPINLOCK(clk_gate_lock);
static void __iomem *base;

static int lan966x_gck_enable(struct clk_hw *hw)
{
        struct lan966x_gck *gck = to_lan966x_gck(hw);
        u32 val = readl(gck->reg);

        val |= GCK_ENA;
        writel(val, gck->reg);

        return 0;
}

static void lan966x_gck_disable(struct clk_hw *hw)
{
        struct lan966x_gck *gck = to_lan966x_gck(hw);
        u32 val = readl(gck->reg);

        val &= ~GCK_ENA;
        writel(val, gck->reg);
}

static int lan966x_gck_set_rate(struct clk_hw *hw,
                                unsigned long rate,
                                unsigned long parent_rate)
{
        struct lan966x_gck *gck = to_lan966x_gck(hw);
        u32 div, val = readl(gck->reg);

        if (rate == 0 || parent_rate == 0)
                return -EINVAL;

        /* Set Prescalar */
        div = parent_rate / rate;
        val &= ~GCK_PRESCALER;
        val |= FIELD_PREP(GCK_PRESCALER, (div - 1));
        writel(val, gck->reg);

        return 0;
}

static unsigned long lan966x_gck_recalc_rate(struct clk_hw *hw,
                                             unsigned long parent_rate)
{
        struct lan966x_gck *gck = to_lan966x_gck(hw);
        u32 div, val = readl(gck->reg);

        div = FIELD_GET(GCK_PRESCALER, val);

        return parent_rate / (div + 1);
}

static int lan966x_gck_determine_rate(struct clk_hw *hw,
                                      struct clk_rate_request *req)
{
        struct clk_hw *parent;
        int i;

        for (i = 0; i < clk_hw_get_num_parents(hw); ++i) {
                parent = clk_hw_get_parent_by_index(hw, i);
                if (!parent)
                        continue;

                /* Allowed prescaler divider range is 0-255 */
                if (clk_hw_get_rate(parent) / req->rate <= DIV_MAX) {
                        req->best_parent_hw = parent;
                        req->best_parent_rate = clk_hw_get_rate(parent);

                        return 0;
                }
        }

        return -EINVAL;
}

static u8 lan966x_gck_get_parent(struct clk_hw *hw)
{
        struct lan966x_gck *gck = to_lan966x_gck(hw);
        u32 val = readl(gck->reg);

        return FIELD_GET(GCK_SRC_SEL, val);
}

static int lan966x_gck_set_parent(struct clk_hw *hw, u8 index)
{
        struct lan966x_gck *gck = to_lan966x_gck(hw);
        u32 val = readl(gck->reg);

        val &= ~GCK_SRC_SEL;
        val |= FIELD_PREP(GCK_SRC_SEL, index);
        writel(val, gck->reg);

        return 0;
}

static const struct clk_ops lan966x_gck_ops = {
        .enable         = lan966x_gck_enable,
        .disable        = lan966x_gck_disable,
        .set_rate       = lan966x_gck_set_rate,
        .recalc_rate    = lan966x_gck_recalc_rate,
        .determine_rate = lan966x_gck_determine_rate,
        .set_parent     = lan966x_gck_set_parent,
        .get_parent     = lan966x_gck_get_parent,
};

static struct clk_hw *lan966x_gck_clk_register(struct device *dev, int i)
{
        struct lan966x_gck *priv;
        int ret;

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

        priv->reg = base + (i * 4);
        priv->hw.init = &init;
        ret = devm_clk_hw_register(dev, &priv->hw);
        if (ret)
                return ERR_PTR(ret);

        return &priv->hw;
};

static int lan966x_gate_clk_register(struct device *dev,
                                     const struct lan966x_match_data *data,
                                     struct clk_hw_onecell_data *hw_data,
                                     void __iomem *gate_base)
{
        for (int i = data->num_generic_clks; i < data->num_total_clks; ++i) {
                int idx = i - data->num_generic_clks;
                const struct clk_gate_soc_desc *desc;

                desc = &data->clk_gate_desc[idx];

                hw_data->hws[i] =
                        devm_clk_hw_register_gate(dev, desc->name,
                                                  data->name, 0, gate_base,
                                                  desc->bit_idx,
                                                  0, &clk_gate_lock);

                if (IS_ERR(hw_data->hws[i]))
                        return dev_err_probe(dev, PTR_ERR(hw_data->hws[i]),
                                             "failed to register %s clock\n",
                                             desc->name);
        }

        return 0;
}

static int lan966x_clk_probe(struct platform_device *pdev)
{
        const struct lan966x_match_data *data;
        struct clk_hw_onecell_data *hw_data;
        struct device *dev = &pdev->dev;
        void __iomem *gate_base;
        struct resource *res;
        int i, ret;

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

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

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

        init.ops = &lan966x_gck_ops;

        hw_data->num = data->num_generic_clks;

        for (i = 0; i < data->num_generic_clks; i++) {
                init.name = data->clk_name[i];
                hw_data->hws[i] = lan966x_gck_clk_register(dev, i);
                if (IS_ERR(hw_data->hws[i])) {
                        dev_err(dev, "failed to register %s clock\n",
                                init.name);
                        return PTR_ERR(hw_data->hws[i]);
                }
        }

        res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        if (res) {
                gate_base = devm_ioremap_resource(&pdev->dev, res);
                if (IS_ERR(gate_base))
                        return PTR_ERR(gate_base);

                hw_data->num = data->num_total_clks;

                ret = lan966x_gate_clk_register(dev, data, hw_data, gate_base);
                if (ret)
                        return ret;
        }

        return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, hw_data);
}

static const struct of_device_id lan966x_clk_dt_ids[] = {
        { .compatible = "microchip,lan966x-gck", .data = &lan966x_desc },
        { .compatible = "microchip,lan9691-gck", .data = &lan969x_desc },
        { }
};
MODULE_DEVICE_TABLE(of, lan966x_clk_dt_ids);

static struct platform_driver lan966x_clk_driver = {
        .probe  = lan966x_clk_probe,
        .driver = {
                .name = "lan966x-clk",
                .of_match_table = lan966x_clk_dt_ids,
        },
};
module_platform_driver(lan966x_clk_driver);

MODULE_AUTHOR("Kavyasree Kotagiri <kavyasree.kotagiri@microchip.com>");
MODULE_DESCRIPTION("LAN966X clock driver");
MODULE_LICENSE("GPL v2");