root/drivers/clk/clk-npcm8xx.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Nuvoton NPCM8xx Clock Generator
 * All the clocks are initialized by the bootloader, so this driver allows only
 * reading of current settings directly from the hardware.
 *
 * Copyright (C) 2020 Nuvoton Technologies
 * Author: Tomer Maimon <tomer.maimon@nuvoton.com>
 */

#define pr_fmt(fmt) "npcm8xx_clk: " fmt

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

#include <dt-bindings/clock/nuvoton,npcm845-clk.h>
#include <soc/nuvoton/clock-npcm8xx.h>

/* npcm8xx clock registers*/
#define NPCM8XX_CLKSEL          0x04
#define NPCM8XX_CLKDIV1         0x08
#define NPCM8XX_CLKDIV2         0x2C
#define NPCM8XX_CLKDIV3         0x58
#define NPCM8XX_CLKDIV4         0x7C
#define NPCM8XX_PLLCON0         0x0C
#define NPCM8XX_PLLCON1         0x10
#define NPCM8XX_PLLCON2         0x54
#define NPCM8XX_PLLCONG         0x60
#define NPCM8XX_THRTL_CNT       0xC0

#define PLLCON_LOKI     BIT(31)
#define PLLCON_LOKS     BIT(30)
#define PLLCON_FBDV     GENMASK(27, 16)
#define PLLCON_OTDV2    GENMASK(15, 13)
#define PLLCON_PWDEN    BIT(12)
#define PLLCON_OTDV1    GENMASK(10, 8)
#define PLLCON_INDV     GENMASK(5, 0)

static void __iomem *clk_base;

struct npcm8xx_clk_pll {
        void __iomem    *pllcon;
        unsigned int    id;
        const char      *name;
        unsigned long   flags;
        struct clk_hw   hw;
};

#define to_npcm8xx_clk_pll(_hw) container_of(_hw, struct npcm8xx_clk_pll, hw)

struct npcm8xx_clk_pll_data {
        const char *name;
        struct clk_parent_data parent;
        unsigned int reg;
        unsigned long flags;
        struct clk_hw hw;
};

struct npcm8xx_clk_div_data {
        u32 reg;
        u8 shift;
        u8 width;
        const char *name;
        const struct clk_hw *parent_hw;
        unsigned long clk_divider_flags;
        unsigned long flags;
        int onecell_idx;
        struct clk_hw hw;
};

struct npcm8xx_clk_mux_data {
        u8 shift;
        u32 mask;
        const u32 *table;
        const char *name;
        const struct clk_parent_data *parent_data;
        u8 num_parents;
        unsigned long flags;
        struct clk_hw hw;
};

static struct clk_hw hw_pll1_div2, hw_pll2_div2, hw_gfx_div2, hw_pre_clk;
static struct npcm8xx_clk_pll_data npcm8xx_pll_clks[] = {
        { "pll0", { .index = 0 }, NPCM8XX_PLLCON0, 0 },
        { "pll1", { .index = 0 }, NPCM8XX_PLLCON1, 0 },
        { "pll2", { .index = 0 }, NPCM8XX_PLLCON2, 0 },
        { "pll_gfx", { .index = 0 }, NPCM8XX_PLLCONG, 0 },
};

static const u32 cpuck_mux_table[] = { 0, 1, 2, 7 };
static const struct clk_parent_data cpuck_mux_parents[] = {
        { .hw = &npcm8xx_pll_clks[0].hw },
        { .hw = &npcm8xx_pll_clks[1].hw },
        { .index = 0 },
        { .hw = &npcm8xx_pll_clks[2].hw }
};

static const u32 pixcksel_mux_table[] = { 0, 2 };
static const struct clk_parent_data pixcksel_mux_parents[] = {
        { .hw = &npcm8xx_pll_clks[3].hw },
        { .index = 0 }
};

static const u32 default_mux_table[] = { 0, 1, 2, 3 };
static const struct clk_parent_data default_mux_parents[] = {
        { .hw = &npcm8xx_pll_clks[0].hw },
        { .hw = &npcm8xx_pll_clks[1].hw },
        { .index = 0 },
        { .hw = &hw_pll2_div2 }
};

static const u32 sucksel_mux_table[] = { 2, 3 };
static const struct clk_parent_data sucksel_mux_parents[] = {
        { .index = 0 },
        { .hw = &hw_pll2_div2 }
};

static const u32 mccksel_mux_table[] = { 0, 2 };
static const struct clk_parent_data mccksel_mux_parents[] = {
        { .hw = &hw_pll1_div2 },
        { .index = 0 }
};

static const u32 clkoutsel_mux_table[] = { 0, 1, 2, 3, 4 };
static const struct clk_parent_data clkoutsel_mux_parents[] = {
        { .hw = &npcm8xx_pll_clks[0].hw },
        { .hw = &npcm8xx_pll_clks[1].hw },
        { .index = 0 },
        { .hw = &hw_gfx_div2 },
        { .hw = &hw_pll2_div2 }
};

static const u32 gfxmsel_mux_table[] = { 2, 3 };
static const struct clk_parent_data gfxmsel_mux_parents[] = {
        { .index = 0 },
        { .hw = &npcm8xx_pll_clks[2].hw }
};

static const u32 dvcssel_mux_table[] = { 2, 3 };
static const struct clk_parent_data dvcssel_mux_parents[] = {
        { .index = 0 },
        { .hw = &npcm8xx_pll_clks[2].hw }
};

static const u32 default3_mux_table[] = { 0, 1, 2 };
static const struct clk_parent_data default3_mux_parents[] = {
        { .hw = &npcm8xx_pll_clks[0].hw },
        { .hw = &npcm8xx_pll_clks[1].hw },
        { .index = 0 }
};

static struct npcm8xx_clk_mux_data npcm8xx_muxes[] = {
        { 0, 3, cpuck_mux_table, "cpu_mux", cpuck_mux_parents,
                ARRAY_SIZE(cpuck_mux_parents), CLK_IS_CRITICAL },
        { 4, 2, pixcksel_mux_table, "gfx_pixel_mux", pixcksel_mux_parents,
                ARRAY_SIZE(pixcksel_mux_parents), 0 },
        { 6, 2, default_mux_table, "sd_mux", default_mux_parents,
                ARRAY_SIZE(default_mux_parents), 0 },
        { 8, 2, default_mux_table, "uart_mux", default_mux_parents,
                ARRAY_SIZE(default_mux_parents), 0 },
        { 10, 2, sucksel_mux_table, "serial_usb_mux", sucksel_mux_parents,
                ARRAY_SIZE(sucksel_mux_parents), 0 },
        { 12, 2, mccksel_mux_table, "mc_mux", mccksel_mux_parents,
                ARRAY_SIZE(mccksel_mux_parents), 0 },
        { 14, 2, default_mux_table, "adc_mux", default_mux_parents,
                ARRAY_SIZE(default_mux_parents), 0 },
        { 16, 2, default_mux_table, "gfx_mux", default_mux_parents,
                ARRAY_SIZE(default_mux_parents), 0 },
        { 18, 3, clkoutsel_mux_table, "clkout_mux", clkoutsel_mux_parents,
                ARRAY_SIZE(clkoutsel_mux_parents), 0 },
        { 21, 2, gfxmsel_mux_table, "gfxm_mux", gfxmsel_mux_parents,
                ARRAY_SIZE(gfxmsel_mux_parents), 0 },
        { 23, 2, dvcssel_mux_table, "dvc_mux", dvcssel_mux_parents,
                ARRAY_SIZE(dvcssel_mux_parents), 0 },
        { 25, 2, default3_mux_table, "rg_mux", default3_mux_parents,
                ARRAY_SIZE(default3_mux_parents), 0 },
        { 27, 2, default3_mux_table, "rcp_mux", default3_mux_parents,
                ARRAY_SIZE(default3_mux_parents), 0 },
};

/* configurable pre dividers: */
static struct npcm8xx_clk_div_data npcm8xx_pre_divs[] = {
        { NPCM8XX_CLKDIV1, 21, 5, "pre_adc", &npcm8xx_muxes[6].hw, CLK_DIVIDER_READ_ONLY, 0, -1 },
        { NPCM8XX_CLKDIV1, 26, 2, "ahb", &hw_pre_clk, CLK_DIVIDER_READ_ONLY, CLK_IS_CRITICAL, NPCM8XX_CLK_AHB },
};

/* configurable dividers: */
static struct npcm8xx_clk_div_data npcm8xx_divs[] = {
        { NPCM8XX_CLKDIV1, 28, 3, "adc", &npcm8xx_pre_divs[0].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_ADC },
        { NPCM8XX_CLKDIV1, 16, 5, "uart", &npcm8xx_muxes[3].hw, 0, 0, NPCM8XX_CLK_UART },
        { NPCM8XX_CLKDIV1, 11, 5, "mmc", &npcm8xx_muxes[2].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_MMC },
        { NPCM8XX_CLKDIV1, 6, 5, "spi3", &npcm8xx_pre_divs[1].hw, 0, 0, NPCM8XX_CLK_SPI3 },
        { NPCM8XX_CLKDIV1, 2, 4, "pci", &npcm8xx_muxes[7].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_PCI },

        { NPCM8XX_CLKDIV2, 30, 2, "apb4", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_APB4 },
        { NPCM8XX_CLKDIV2, 28, 2, "apb3", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_APB3 },
        { NPCM8XX_CLKDIV2, 26, 2, "apb2", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_APB2 },
        { NPCM8XX_CLKDIV2, 24, 2, "apb1", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_APB1 },
        { NPCM8XX_CLKDIV2, 22, 2, "apb5", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_APB5 },
        { NPCM8XX_CLKDIV2, 16, 5, "clkout", &npcm8xx_muxes[8].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_CLKOUT },
        { NPCM8XX_CLKDIV2, 13, 3, "gfx", &npcm8xx_muxes[7].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_GFX },
        { NPCM8XX_CLKDIV2, 8, 5, "usb_bridge", &npcm8xx_muxes[4].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SU },
        { NPCM8XX_CLKDIV2, 4, 4, "usb_host", &npcm8xx_muxes[4].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SU48 },
        { NPCM8XX_CLKDIV2, 0, 4, "sdhc", &npcm8xx_muxes[2].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SDHC },

        { NPCM8XX_CLKDIV3, 16, 8, "spi1", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SPI1 },
        { NPCM8XX_CLKDIV3, 11, 5, "uart2", &npcm8xx_muxes[3].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_UART2 },
        { NPCM8XX_CLKDIV3, 6, 5, "spi0", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SPI0 },
        { NPCM8XX_CLKDIV3, 1, 5, "spix", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SPIX },

        { NPCM8XX_CLKDIV4, 28, 4, "rg", &npcm8xx_muxes[11].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_RG },
        { NPCM8XX_CLKDIV4, 12, 4, "rcp", &npcm8xx_muxes[12].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_RCP },

        { NPCM8XX_THRTL_CNT, 0, 2, "th", &npcm8xx_muxes[0].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_TH },
};

static unsigned long npcm8xx_clk_pll_recalc_rate(struct clk_hw *hw,
                                                 unsigned long parent_rate)
{
        struct npcm8xx_clk_pll *pll = to_npcm8xx_clk_pll(hw);
        unsigned long fbdv, indv, otdv1, otdv2;
        unsigned int val;
        u64 ret;

        if (parent_rate == 0) {
                pr_debug("%s: parent rate is zero\n", __func__);
                return 0;
        }

        val = readl_relaxed(pll->pllcon);

        indv = FIELD_GET(PLLCON_INDV, val);
        fbdv = FIELD_GET(PLLCON_FBDV, val);
        otdv1 = FIELD_GET(PLLCON_OTDV1, val);
        otdv2 = FIELD_GET(PLLCON_OTDV2, val);

        ret = (u64)parent_rate * fbdv;
        do_div(ret, indv * otdv1 * otdv2);

        return ret;
}

static const struct clk_ops npcm8xx_clk_pll_ops = {
        .recalc_rate = npcm8xx_clk_pll_recalc_rate,
};

static struct clk_hw *
npcm8xx_clk_register_pll(struct device *dev, void __iomem *pllcon,
                         const char *name, const struct clk_parent_data *parent,
                         unsigned long flags)
{
        struct npcm8xx_clk_pll *pll;
        struct clk_init_data init = {};
        int ret;

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

        init.name = name;
        init.ops = &npcm8xx_clk_pll_ops;
        init.parent_data = parent;
        init.num_parents = 1;
        init.flags = flags;

        pll->pllcon = pllcon;
        pll->hw.init = &init;

        ret = devm_clk_hw_register(dev, &pll->hw);
        if (ret)
                return ERR_PTR(ret);

        return &pll->hw;
}

static DEFINE_SPINLOCK(npcm8xx_clk_lock);

static int npcm8xx_clk_probe(struct auxiliary_device *adev,
                             const struct auxiliary_device_id *id)
{
        struct npcm_clock_adev *rdev = to_npcm_clock_adev(adev);
        struct clk_hw_onecell_data *npcm8xx_clk_data;
        struct device *dev = &adev->dev;
        struct clk_hw *hw;
        unsigned int i;

        npcm8xx_clk_data = devm_kzalloc(dev, struct_size(npcm8xx_clk_data, hws,
                                                         NPCM8XX_NUM_CLOCKS),
                                        GFP_KERNEL);
        if (!npcm8xx_clk_data)
                return -ENOMEM;

        clk_base = rdev->base;

        npcm8xx_clk_data->num = NPCM8XX_NUM_CLOCKS;

        for (i = 0; i < NPCM8XX_NUM_CLOCKS; i++)
                npcm8xx_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);

        /* Register plls */
        for (i = 0; i < ARRAY_SIZE(npcm8xx_pll_clks); i++) {
                struct npcm8xx_clk_pll_data *pll_clk = &npcm8xx_pll_clks[i];

                hw = npcm8xx_clk_register_pll(dev, clk_base + pll_clk->reg,
                                              pll_clk->name, &pll_clk->parent,
                                              pll_clk->flags);
                if (IS_ERR(hw))
                        return dev_err_probe(dev, PTR_ERR(hw), "Can't register pll\n");
                pll_clk->hw = *hw;
        }

        /* Register fixed dividers */
        hw = devm_clk_hw_register_fixed_factor(dev, "pll1_div2", "pll1", 0, 1, 2);
        if (IS_ERR(hw))
                return dev_err_probe(dev, PTR_ERR(hw), "Can't register fixed div\n");
        hw_pll1_div2 = *hw;

        hw = devm_clk_hw_register_fixed_factor(dev, "pll2_div2", "pll2", 0, 1, 2);
        if (IS_ERR(hw))
                return dev_err_probe(dev, PTR_ERR(hw), "Can't register pll2 div2\n");
        hw_pll2_div2 = *hw;

        hw = devm_clk_hw_register_fixed_factor(dev, "pll_gfx_div2", "pll_gfx", 0, 1, 2);
        if (IS_ERR(hw))
                return dev_err_probe(dev, PTR_ERR(hw), "Can't register gfx div2\n");
        hw_gfx_div2 = *hw;

        /* Register muxes */
        for (i = 0; i < ARRAY_SIZE(npcm8xx_muxes); i++) {
                struct npcm8xx_clk_mux_data *mux_data = &npcm8xx_muxes[i];

                hw = devm_clk_hw_register_mux_parent_data_table(dev,
                                                                mux_data->name,
                                                                mux_data->parent_data,
                                                                mux_data->num_parents,
                                                                mux_data->flags,
                                                                clk_base + NPCM8XX_CLKSEL,
                                                                mux_data->shift,
                                                                mux_data->mask,
                                                                0,
                                                                mux_data->table,
                                                                &npcm8xx_clk_lock);
                if (IS_ERR(hw))
                        return dev_err_probe(dev, PTR_ERR(hw), "Can't register mux\n");
                mux_data->hw = *hw;
        }

        hw = devm_clk_hw_register_fixed_factor(dev, "pre_clk", "cpu_mux", 0, 1, 2);
        if (IS_ERR(hw))
                return dev_err_probe(dev, PTR_ERR(hw), "Can't register pre clk div2\n");
        hw_pre_clk = *hw;

        hw = devm_clk_hw_register_fixed_factor(dev, "axi", "th", 0, 1, 2);
        if (IS_ERR(hw))
                return dev_err_probe(dev, PTR_ERR(hw), "Can't register axi div2\n");
        npcm8xx_clk_data->hws[NPCM8XX_CLK_AXI] = hw;

        hw = devm_clk_hw_register_fixed_factor(dev, "atb", "axi", 0, 1, 2);
        if (IS_ERR(hw))
                return dev_err_probe(dev, PTR_ERR(hw), "Can't register atb div2\n");
        npcm8xx_clk_data->hws[NPCM8XX_CLK_ATB] = hw;

        /* Register pre dividers */
        for (i = 0; i < ARRAY_SIZE(npcm8xx_pre_divs); i++) {
                struct npcm8xx_clk_div_data *div_data = &npcm8xx_pre_divs[i];

                hw = devm_clk_hw_register_divider_parent_hw(dev, div_data->name,
                                                            div_data->parent_hw,
                                                            div_data->flags,
                                                            clk_base + div_data->reg,
                                                            div_data->shift,
                                                            div_data->width,
                                                            div_data->clk_divider_flags,
                                                            &npcm8xx_clk_lock);
                if (IS_ERR(hw))
                        return dev_err_probe(dev, PTR_ERR(hw), "Can't register pre div\n");
                div_data->hw = *hw;

                if (div_data->onecell_idx >= 0)
                        npcm8xx_clk_data->hws[div_data->onecell_idx] = hw;
        }

        /* Register dividers */
        for (i = 0; i < ARRAY_SIZE(npcm8xx_divs); i++) {
                struct npcm8xx_clk_div_data *div_data = &npcm8xx_divs[i];

                hw = devm_clk_hw_register_divider_parent_hw(dev, div_data->name,
                                                            div_data->parent_hw,
                                                            div_data->flags,
                                                            clk_base + div_data->reg,
                                                            div_data->shift,
                                                            div_data->width,
                                                            div_data->clk_divider_flags,
                                                            &npcm8xx_clk_lock);
                if (IS_ERR(hw))
                        return dev_err_probe(dev, PTR_ERR(hw), "Can't register div\n");

                if (div_data->onecell_idx >= 0)
                        npcm8xx_clk_data->hws[div_data->onecell_idx] = hw;
        }

        return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
                                          npcm8xx_clk_data);
}

static const struct auxiliary_device_id npcm8xx_clock_ids[] = {
        {
                .name = "reset_npcm.clk-npcm8xx",
        },
        { }
};
MODULE_DEVICE_TABLE(auxiliary, npcm8xx_clock_ids);

static struct auxiliary_driver npcm8xx_clock_driver = {
        .probe          = npcm8xx_clk_probe,
        .id_table       = npcm8xx_clock_ids,
};
module_auxiliary_driver(npcm8xx_clock_driver);

MODULE_DESCRIPTION("Clock driver for Nuvoton NPCM8XX BMC SoC");
MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
MODULE_LICENSE("GPL v2");