/*
 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
 * Author(s): Patrice Chotard, <patrice.chotard@st.com> for STMicroelectronics.
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#include <common.h>
#include <clk-uclass.h>
#include <dm.h>
#include <regmap.h>
#include <syscon.h>
#include <asm/io.h>
#include <dm/root.h>

#include <dt-bindings/clock/stm32h7-clks.h>

DECLARE_GLOBAL_DATA_PTR;

/* RCC CR specific definitions */
#define RCC_CR_HSION                    BIT(0)
#define RCC_CR_HSIRDY                   BIT(2)

#define RCC_CR_HSEON                    BIT(16)
#define RCC_CR_HSERDY                   BIT(17)
#define RCC_CR_HSEBYP                   BIT(18)
#define RCC_CR_PLL1ON                   BIT(24)
#define RCC_CR_PLL1RDY                  BIT(25)

#define RCC_CR_HSIDIV_MASK              GENMASK(4, 3)
#define RCC_CR_HSIDIV_SHIFT             3

#define RCC_CFGR_SW_MASK                GENMASK(2, 0)
#define RCC_CFGR_SW_HSI                 0
#define RCC_CFGR_SW_CSI                 1
#define RCC_CFGR_SW_HSE                 2
#define RCC_CFGR_SW_PLL1                3

#define RCC_PLLCKSELR_PLLSRC_HSI        0
#define RCC_PLLCKSELR_PLLSRC_CSI        1
#define RCC_PLLCKSELR_PLLSRC_HSE        2
#define RCC_PLLCKSELR_PLLSRC_NO_CLK     3

#define RCC_PLLCKSELR_PLLSRC_MASK       GENMASK(1, 0)

#define RCC_PLLCKSELR_DIVM1_SHIFT       4
#define RCC_PLLCKSELR_DIVM1_MASK        GENMASK(9, 4)

#define RCC_PLL1DIVR_DIVN1_MASK         GENMASK(8, 0)

#define RCC_PLL1DIVR_DIVP1_SHIFT        9
#define RCC_PLL1DIVR_DIVP1_MASK         GENMASK(15, 9)

#define RCC_PLL1DIVR_DIVQ1_SHIFT        16
#define RCC_PLL1DIVR_DIVQ1_MASK         GENMASK(22, 16)

#define RCC_PLL1DIVR_DIVR1_SHIFT        24
#define RCC_PLL1DIVR_DIVR1_MASK         GENMASK(30, 24)

#define RCC_PLL1FRACR_FRACN1_SHIFT      3
#define RCC_PLL1FRACR_FRACN1_MASK       GENMASK(15, 3)

#define RCC_PLLCFGR_PLL1RGE_SHIFT       2
#define         PLL1RGE_1_2_MHZ         0
#define         PLL1RGE_2_4_MHZ         1
#define         PLL1RGE_4_8_MHZ         2
#define         PLL1RGE_8_16_MHZ        3
#define RCC_PLLCFGR_DIVP1EN             BIT(16)
#define RCC_PLLCFGR_DIVQ1EN             BIT(17)
#define RCC_PLLCFGR_DIVR1EN             BIT(18)

#define RCC_D1CFGR_HPRE_MASK            GENMASK(3, 0)
#define RCC_D1CFGR_HPRE_DIVIDED         BIT(3)
#define RCC_D1CFGR_HPRE_DIVIDER         GENMASK(2, 0)

#define RCC_D1CFGR_HPRE_DIV2            8

#define RCC_D1CFGR_D1PPRE_SHIFT         4
#define RCC_D1CFGR_D1PPRE_DIVIDED       BIT(6)
#define RCC_D1CFGR_D1PPRE_DIVIDER       GENMASK(5, 4)

#define RCC_D1CFGR_D1CPRE_SHIFT         8
#define RCC_D1CFGR_D1CPRE_DIVIDER       GENMASK(10, 8)
#define RCC_D1CFGR_D1CPRE_DIVIDED       BIT(11)

#define RCC_D2CFGR_D2PPRE1_SHIFT        4
#define RCC_D2CFGR_D2PPRE1_DIVIDED      BIT(6)
#define RCC_D2CFGR_D2PPRE1_DIVIDER      GENMASK(5, 4)

#define RCC_D2CFGR_D2PPRE2_SHIFT        8
#define RCC_D2CFGR_D2PPRE2_DIVIDED      BIT(10)
#define RCC_D2CFGR_D2PPRE2_DIVIDER      GENMASK(9, 8)

#define RCC_D3CFGR_D3PPRE_SHIFT         4
#define RCC_D3CFGR_D3PPRE_DIVIDED       BIT(6)
#define RCC_D3CFGR_D3PPRE_DIVIDER       GENMASK(5, 4)

#define RCC_D1CCIPR_FMCSRC_MASK         GENMASK(1, 0)
#define         FMCSRC_HCLKD1           0
#define         FMCSRC_PLL1_Q_CK        1
#define         FMCSRC_PLL2_R_CK        2
#define         FMCSRC_PER_CK           3

#define RCC_D1CCIPR_QSPISRC_MASK        GENMASK(5, 4)
#define RCC_D1CCIPR_QSPISRC_SHIFT       4
#define         QSPISRC_HCLKD1          0
#define         QSPISRC_PLL1_Q_CK       1
#define         QSPISRC_PLL2_R_CK       2
#define         QSPISRC_PER_CK          3

#define PWR_CR3                         0x0c
#define PWR_CR3_SCUEN                   BIT(2)
#define PWR_D3CR                        0x18
#define PWR_D3CR_VOS_MASK               GENMASK(15, 14)
#define PWR_D3CR_VOS_SHIFT              14
#define         VOS_SCALE_3             1
#define         VOS_SCALE_2             2
#define         VOS_SCALE_1             3
#define PWR_D3CR_VOSREADY               BIT(13)

struct stm32_rcc_regs {
        u32 cr;         /* 0x00 Source Control Register */
        u32 icscr;      /* 0x04 Internal Clock Source Calibration Register */
        u32 crrcr;      /* 0x08 Clock Recovery RC Register */
        u32 reserved1;  /* 0x0c reserved */
        u32 cfgr;       /* 0x10 Clock Configuration Register */
        u32 reserved2;  /* 0x14 reserved */
        u32 d1cfgr;     /* 0x18 Domain 1 Clock Configuration Register */
        u32 d2cfgr;     /* 0x1c Domain 2 Clock Configuration Register */
        u32 d3cfgr;     /* 0x20 Domain 3 Clock Configuration Register */
        u32 reserved3;  /* 0x24 reserved */
        u32 pllckselr;  /* 0x28 PLLs Clock Source Selection Register */
        u32 pllcfgr;    /* 0x2c PLLs Configuration Register */
        u32 pll1divr;   /* 0x30 PLL1 Dividers Configuration Register */
        u32 pll1fracr;  /* 0x34 PLL1 Fractional Divider Register */
        u32 pll2divr;   /* 0x38 PLL2 Dividers Configuration Register */
        u32 pll2fracr;  /* 0x3c PLL2 Fractional Divider Register */
        u32 pll3divr;   /* 0x40 PLL3 Dividers Configuration Register */
        u32 pll3fracr;  /* 0x44 PLL3 Fractional Divider Register */
        u32 reserved4;  /* 0x48 reserved */
        u32 d1ccipr;    /* 0x4c Domain 1 Kernel Clock Configuration Register */
        u32 d2ccip1r;   /* 0x50 Domain 2 Kernel Clock Configuration Register */
        u32 d2ccip2r;   /* 0x54 Domain 2 Kernel Clock Configuration Register */
        u32 d3ccipr;    /* 0x58 Domain 3 Kernel Clock Configuration Register */
        u32 reserved5;  /* 0x5c reserved */
        u32 cier;       /* 0x60 Clock Source Interrupt Enable Register */
        u32 cifr;       /* 0x64 Clock Source Interrupt Flag Register */
        u32 cicr;       /* 0x68 Clock Source Interrupt Clear Register */
        u32 reserved6;  /* 0x6c reserved */
        u32 bdcr;       /* 0x70 Backup Domain Control Register */
        u32 csr;        /* 0x74 Clock Control and Status Register */
        u32 reserved7;  /* 0x78 reserved */

        u32 ahb3rstr;   /* 0x7c AHB3 Peripheral Reset Register */
        u32 ahb1rstr;   /* 0x80 AHB1 Peripheral Reset Register */
        u32 ahb2rstr;   /* 0x84 AHB2 Peripheral Reset Register */
        u32 ahb4rstr;   /* 0x88 AHB4 Peripheral Reset Register */

        u32 apb3rstr;   /* 0x8c APB3 Peripheral Reset Register */
        u32 apb1lrstr;  /* 0x90 APB1 low Peripheral Reset Register */
        u32 apb1hrstr;  /* 0x94 APB1 high Peripheral Reset Register */
        u32 apb2rstr;   /* 0x98 APB2 Clock Register */
        u32 apb4rstr;   /* 0x9c APB4 Clock Register */

        u32 gcr;        /* 0xa0 Global Control Register */
        u32 reserved8;  /* 0xa4 reserved */
        u32 d3amr;      /* 0xa8 D3 Autonomous mode Register */
        u32 reserved9[9];/* 0xac to 0xcc reserved */
        u32 rsr;        /* 0xd0 Reset Status Register */
        u32 ahb3enr;    /* 0xd4 AHB3 Clock Register */
        u32 ahb1enr;    /* 0xd8 AHB1 Clock Register */
        u32 ahb2enr;    /* 0xdc AHB2 Clock Register */
        u32 ahb4enr;    /* 0xe0 AHB4 Clock Register */

        u32 apb3enr;    /* 0xe4 APB3 Clock Register */
        u32 apb1lenr;   /* 0xe8 APB1 low Clock Register */
        u32 apb1henr;   /* 0xec APB1 high Clock Register */
        u32 apb2enr;    /* 0xf0 APB2 Clock Register */
        u32 apb4enr;    /* 0xf4 APB4 Clock Register */
};

#define RCC_AHB3ENR     offsetof(struct stm32_rcc_regs, ahb3enr)
#define RCC_AHB1ENR     offsetof(struct stm32_rcc_regs, ahb1enr)
#define RCC_AHB2ENR     offsetof(struct stm32_rcc_regs, ahb2enr)
#define RCC_AHB4ENR     offsetof(struct stm32_rcc_regs, ahb4enr)
#define RCC_APB3ENR     offsetof(struct stm32_rcc_regs, apb3enr)
#define RCC_APB1LENR    offsetof(struct stm32_rcc_regs, apb1lenr)
#define RCC_APB1HENR    offsetof(struct stm32_rcc_regs, apb1henr)
#define RCC_APB2ENR     offsetof(struct stm32_rcc_regs, apb2enr)
#define RCC_APB4ENR     offsetof(struct stm32_rcc_regs, apb4enr)

struct clk_cfg {
        u32 gate_offset;
        u8  gate_bit_idx;
        const char *name;
};

/*
 * the way all these entries are sorted in this array could seem
 * unlogical, but we are dependant of kernel DT_bindings,
 * where clocks are separate in 2 banks, peripheral clocks and
 * kernel clocks.
 */

static const struct clk_cfg clk_map[] = {
        {RCC_AHB3ENR,  31, "d1sram1"},  /* peripheral clocks */
        {RCC_AHB3ENR,  30, "itcm"},
        {RCC_AHB3ENR,  29, "dtcm2"},
        {RCC_AHB3ENR,  28, "dtcm1"},
        {RCC_AHB3ENR,   8, "flitf"},
        {RCC_AHB3ENR,   5, "jpgdec"},
        {RCC_AHB3ENR,   4, "dma2d"},
        {RCC_AHB3ENR,   0, "mdma"},
        {RCC_AHB1ENR,  28, "usb2ulpi"},
        {RCC_AHB1ENR,  17, "eth1rx"},
        {RCC_AHB1ENR,  16, "eth1tx"},
        {RCC_AHB1ENR,  15, "eth1mac"},
        {RCC_AHB1ENR,  14, "art"},
        {RCC_AHB1ENR,  26, "usb1ulpi"},
        {RCC_AHB1ENR,   1, "dma2"},
        {RCC_AHB1ENR,   0, "dma1"},
        {RCC_AHB2ENR,  31, "d2sram3"},
        {RCC_AHB2ENR,  30, "d2sram2"},
        {RCC_AHB2ENR,  29, "d2sram1"},
        {RCC_AHB2ENR,   5, "hash"},
        {RCC_AHB2ENR,   4, "crypt"},
        {RCC_AHB2ENR,   0, "camitf"},
        {RCC_AHB4ENR,  28, "bkpram"},
        {RCC_AHB4ENR,  25, "hsem"},
        {RCC_AHB4ENR,  21, "bdma"},
        {RCC_AHB4ENR,  19, "crc"},
        {RCC_AHB4ENR,  10, "gpiok"},
        {RCC_AHB4ENR,   9, "gpioj"},
        {RCC_AHB4ENR,   8, "gpioi"},
        {RCC_AHB4ENR,   7, "gpioh"},
        {RCC_AHB4ENR,   6, "gpiog"},
        {RCC_AHB4ENR,   5, "gpiof"},
        {RCC_AHB4ENR,   4, "gpioe"},
        {RCC_AHB4ENR,   3, "gpiod"},
        {RCC_AHB4ENR,   2, "gpioc"},
        {RCC_AHB4ENR,   1, "gpiob"},
        {RCC_AHB4ENR,   0, "gpioa"},
        {RCC_APB3ENR,   6, "wwdg1"},
        {RCC_APB1LENR, 29, "dac12"},
        {RCC_APB1LENR, 11, "wwdg2"},
        {RCC_APB1LENR,  8, "tim14"},
        {RCC_APB1LENR,  7, "tim13"},
        {RCC_APB1LENR,  6, "tim12"},
        {RCC_APB1LENR,  5, "tim7"},
        {RCC_APB1LENR,  4, "tim6"},
        {RCC_APB1LENR,  3, "tim5"},
        {RCC_APB1LENR,  2, "tim4"},
        {RCC_APB1LENR,  1, "tim3"},
        {RCC_APB1LENR,  0, "tim2"},
        {RCC_APB1HENR,  5, "mdios"},
        {RCC_APB1HENR,  4, "opamp"},
        {RCC_APB1HENR,  1, "crs"},
        {RCC_APB2ENR,  18, "tim17"},
        {RCC_APB2ENR,  17, "tim16"},
        {RCC_APB2ENR,  16, "tim15"},
        {RCC_APB2ENR,   1, "tim8"},
        {RCC_APB2ENR,   0, "tim1"},
        {RCC_APB4ENR,  26, "tmpsens"},
        {RCC_APB4ENR,  16, "rtcapb"},
        {RCC_APB4ENR,  15, "vref"},
        {RCC_APB4ENR,  14, "comp12"},
        {RCC_APB4ENR,   1, "syscfg"},
        {RCC_AHB3ENR,  16, "sdmmc1"},   /* kernel clocks */
        {RCC_AHB3ENR,  14, "quadspi"},
        {RCC_AHB3ENR,  12, "fmc"},
        {RCC_AHB1ENR,  27, "usb2otg"},
        {RCC_AHB1ENR,  25, "usb1otg"},
        {RCC_AHB1ENR,   5, "adc12"},
        {RCC_AHB2ENR,   9, "sdmmc2"},
        {RCC_AHB2ENR,   6, "rng"},
        {RCC_AHB4ENR,  24, "adc3"},
        {RCC_APB3ENR,   4, "dsi"},
        {RCC_APB3ENR,   3, "ltdc"},
        {RCC_APB1LENR, 31, "usart8"},
        {RCC_APB1LENR, 30, "usart7"},
        {RCC_APB1LENR, 27, "hdmicec"},
        {RCC_APB1LENR, 23, "i2c3"},
        {RCC_APB1LENR, 22, "i2c2"},
        {RCC_APB1LENR, 21, "i2c1"},
        {RCC_APB1LENR, 20, "uart5"},
        {RCC_APB1LENR, 19, "uart4"},
        {RCC_APB1LENR, 18, "usart3"},
        {RCC_APB1LENR, 17, "usart2"},
        {RCC_APB1LENR, 16, "spdifrx"},
        {RCC_APB1LENR, 15, "spi3"},
        {RCC_APB1LENR, 14, "spi2"},
        {RCC_APB1LENR,  9, "lptim1"},
        {RCC_APB1HENR,  8, "fdcan"},
        {RCC_APB1HENR,  2, "swp"},
        {RCC_APB2ENR,  29, "hrtim"},
        {RCC_APB2ENR,  28, "dfsdm1"},
        {RCC_APB2ENR,  24, "sai3"},
        {RCC_APB2ENR,  23, "sai2"},
        {RCC_APB2ENR,  22, "sai1"},
        {RCC_APB2ENR,  20, "spi5"},
        {RCC_APB2ENR,  13, "spi4"},
        {RCC_APB2ENR,  12, "spi1"},
        {RCC_APB2ENR,   5, "usart6"},
        {RCC_APB2ENR,   4, "usart1"},
        {RCC_APB4ENR,  21, "sai4a"},
        {RCC_APB4ENR,  21, "sai4b"},
        {RCC_APB4ENR,  12, "lptim5"},
        {RCC_APB4ENR,  11, "lptim4"},
        {RCC_APB4ENR,  10, "lptim3"},
        {RCC_APB4ENR,   9, "lptim2"},
        {RCC_APB4ENR,   7, "i2c4"},
        {RCC_APB4ENR,   5,  "spi6"},
        {RCC_APB4ENR,   3, "lpuart1"},
};

struct stm32_clk {
        struct stm32_rcc_regs *rcc_base;
        struct regmap *pwr_regmap;
};

struct pll_psc {
        u8      divm;
        u16     divn;
        u8      divp;
        u8      divq;
        u8      divr;
};

/*
 * OSC_HSE = 25 MHz
 * VCO = 500MHz
 * pll1_p = 250MHz / pll1_q = 250MHz pll1_r = 250Mhz
 */
struct pll_psc sys_pll_psc = {
        .divm = 4,
        .divn = 80,
        .divp = 2,
        .divq = 2,
        .divr = 2,
};

int configure_clocks(struct udevice *dev)
{
        struct stm32_clk *priv = dev_get_priv(dev);
        struct stm32_rcc_regs *regs = priv->rcc_base;
        uint8_t *pwr_base = (uint8_t *)regmap_get_range(priv->pwr_regmap, 0);
        uint32_t pllckselr = 0;
        uint32_t pll1divr = 0;
        uint32_t pllcfgr = 0;

        /* Switch on HSI */
        setbits_le32(&regs->cr, RCC_CR_HSION);
        while (!(readl(&regs->cr) & RCC_CR_HSIRDY))
                ;

        /* Reset CFGR, now HSI is the default system clock */
        writel(0, &regs->cfgr);

        /* Set all kernel domain clock registers to reset value*/
        writel(0x0, &regs->d1ccipr);
        writel(0x0, &regs->d2ccip1r);
        writel(0x0, &regs->d2ccip2r);

        /* Set voltage scaling at scale 1 (1,15 - 1,26 Volts) */
        clrsetbits_le32(pwr_base + PWR_D3CR, PWR_D3CR_VOS_MASK,
                        VOS_SCALE_1 << PWR_D3CR_VOS_SHIFT);
        /* Lock supply configuration update */
        clrbits_le32(pwr_base + PWR_CR3, PWR_CR3_SCUEN);
        while (!(readl(pwr_base + PWR_D3CR) & PWR_D3CR_VOSREADY))
                ;

        /* disable HSE to configure it  */
        clrbits_le32(&regs->cr, RCC_CR_HSEON);
        while ((readl(&regs->cr) & RCC_CR_HSERDY))
                ;

        /* clear HSE bypass and set it ON */
        clrbits_le32(&regs->cr, RCC_CR_HSEBYP);
        /* Switch on HSE */
        setbits_le32(&regs->cr, RCC_CR_HSEON);
        while (!(readl(&regs->cr) & RCC_CR_HSERDY))
                ;

        /* pll setup, disable it */
        clrbits_le32(&regs->cr, RCC_CR_PLL1ON);
        while ((readl(&regs->cr) & RCC_CR_PLL1RDY))
                ;

        /* Select HSE as PLL clock source */
        pllckselr |= RCC_PLLCKSELR_PLLSRC_HSE;
        pllckselr |= sys_pll_psc.divm << RCC_PLLCKSELR_DIVM1_SHIFT;
        writel(pllckselr, &regs->pllckselr);

        pll1divr |= (sys_pll_psc.divr - 1) << RCC_PLL1DIVR_DIVR1_SHIFT;
        pll1divr |= (sys_pll_psc.divq - 1) << RCC_PLL1DIVR_DIVQ1_SHIFT;
        pll1divr |= (sys_pll_psc.divp - 1) << RCC_PLL1DIVR_DIVP1_SHIFT;
        pll1divr |= (sys_pll_psc.divn - 1);
        writel(pll1divr, &regs->pll1divr);

        pllcfgr |= PLL1RGE_4_8_MHZ << RCC_PLLCFGR_PLL1RGE_SHIFT;
        pllcfgr |= RCC_PLLCFGR_DIVP1EN;
        pllcfgr |= RCC_PLLCFGR_DIVQ1EN;
        pllcfgr |= RCC_PLLCFGR_DIVR1EN;
        writel(pllcfgr, &regs->pllcfgr);

        /* pll setup, enable it */
        setbits_le32(&regs->cr, RCC_CR_PLL1ON);

        /* set HPRE (/2) DI clk --> 125MHz */
        clrsetbits_le32(&regs->d1cfgr, RCC_D1CFGR_HPRE_MASK,
                        RCC_D1CFGR_HPRE_DIV2);

        /*  select PLL1 as system clock source (sys_ck)*/
        clrsetbits_le32(&regs->cfgr, RCC_CFGR_SW_MASK, RCC_CFGR_SW_PLL1);
        while ((readl(&regs->cfgr) & RCC_CFGR_SW_MASK) != RCC_CFGR_SW_PLL1)
                ;

        /* sdram: use pll1_q as fmc_k clk */
        clrsetbits_le32(&regs->d1ccipr, RCC_D1CCIPR_FMCSRC_MASK,
                        FMCSRC_PLL1_Q_CK);

        return 0;
}

static u32 stm32_get_HSI_divider(struct stm32_rcc_regs *regs)
{
        u32 divider;

        /* get HSI divider value */
        divider = readl(&regs->cr) & RCC_CR_HSIDIV_MASK;
        divider = divider >> RCC_CR_HSIDIV_SHIFT;

        return divider;
};

enum pllsrc {
        HSE,
        LSE,
        HSI,
        CSI,
        I2S,
        TIMER,
        PLLSRC_NB,
};

static const char * const pllsrc_name[PLLSRC_NB] = {
        [HSE] = "clk-hse",
        [LSE] = "clk-lse",
        [HSI] = "clk-hsi",
        [CSI] = "clk-csi",
        [I2S] = "clk-i2s",
        [TIMER] = "timer-clk"
};

static ulong stm32_get_rate(struct stm32_rcc_regs *regs, enum pllsrc pllsrc)
{
        struct clk clk;
        struct udevice *fixed_clock_dev = NULL;
        u32 divider;
        int ret;
        const char *name = pllsrc_name[pllsrc];

        debug("%s name %s\n", __func__, name);

        clk.id = 0;
        ret = uclass_get_device_by_name(UCLASS_CLK, name, &fixed_clock_dev);
        if (ret) {
                pr_err("Can't find clk %s (%d)", name, ret);
                return 0;
        }

        ret = clk_request(fixed_clock_dev, &clk);
        if (ret) {
                pr_err("Can't request %s clk (%d)", name, ret);
                return 0;
        }

        divider = 0;
        if (pllsrc == HSI)
                divider = stm32_get_HSI_divider(regs);

        debug("%s divider %d rate %ld\n", __func__,
              divider, clk_get_rate(&clk));

        return clk_get_rate(&clk) >> divider;
};

enum pll1_output {
        PLL1_P_CK,
        PLL1_Q_CK,
        PLL1_R_CK,
};

static u32 stm32_get_PLL1_rate(struct stm32_rcc_regs *regs,
                               enum pll1_output output)
{
        ulong pllsrc = 0;
        u32 divm1, divn1, divp1, divq1, divr1, fracn1;
        ulong vco, rate;

        /* get the PLLSRC */
        switch (readl(&regs->pllckselr) & RCC_PLLCKSELR_PLLSRC_MASK) {
        case RCC_PLLCKSELR_PLLSRC_HSI:
                pllsrc = stm32_get_rate(regs, HSI);
                break;
        case RCC_PLLCKSELR_PLLSRC_CSI:
                pllsrc = stm32_get_rate(regs, CSI);
                break;
        case RCC_PLLCKSELR_PLLSRC_HSE:
                pllsrc = stm32_get_rate(regs, HSE);
                break;
        case RCC_PLLCKSELR_PLLSRC_NO_CLK:
                /* shouldn't happen */
                pr_err("wrong value for RCC_PLLCKSELR register\n");
                pllsrc = 0;
                break;
        }

        /* pllsrc = 0 ? no need to go ahead */
        if (!pllsrc)
                return pllsrc;

        /* get divm1, divp1, divn1 and divr1 */
        divm1 = readl(&regs->pllckselr) & RCC_PLLCKSELR_DIVM1_MASK;
        divm1 = divm1 >> RCC_PLLCKSELR_DIVM1_SHIFT;

        divn1 = (readl(&regs->pll1divr) & RCC_PLL1DIVR_DIVN1_MASK) + 1;

        divp1 = readl(&regs->pll1divr) & RCC_PLL1DIVR_DIVP1_MASK;
        divp1 = (divp1 >> RCC_PLL1DIVR_DIVP1_SHIFT) + 1;

        divq1 = readl(&regs->pll1divr) & RCC_PLL1DIVR_DIVQ1_MASK;
        divq1 = (divq1 >> RCC_PLL1DIVR_DIVQ1_SHIFT) + 1;

        divr1 = readl(&regs->pll1divr) & RCC_PLL1DIVR_DIVR1_MASK;
        divr1 = (divr1 >> RCC_PLL1DIVR_DIVR1_SHIFT) + 1;

        fracn1 = readl(&regs->pll1fracr) & RCC_PLL1DIVR_DIVR1_MASK;
        fracn1 = fracn1 & RCC_PLL1DIVR_DIVR1_SHIFT;

        vco = (pllsrc / divm1) * divn1;
        rate = (pllsrc * fracn1) / (divm1 * 8192);

        debug("%s divm1 = %d divn1 = %d divp1 = %d divq1 = %d divr1 = %d\n",
              __func__, divm1, divn1, divp1, divq1, divr1);
        debug("%s fracn1 = %d vco = %ld rate = %ld\n",
              __func__, fracn1, vco, rate);

        switch (output) {
        case PLL1_P_CK:
                return (vco + rate) / divp1;
                break;
        case PLL1_Q_CK:
                return (vco + rate) / divq1;
                break;

        case PLL1_R_CK:
                return (vco + rate) / divr1;
                break;
        }

        return -EINVAL;
}

static ulong stm32_clk_get_rate(struct clk *clk)
{
        struct stm32_clk *priv = dev_get_priv(clk->dev);
        struct stm32_rcc_regs *regs = priv->rcc_base;
        ulong sysclk = 0;
        u32 gate_offset;
        u32 d1cfgr;
        /* prescaler table lookups for clock computation */
        u16 prescaler_table[8] = {2, 4, 8, 16, 64, 128, 256, 512};
        u8 source, idx;

        /*
         * get system clock (sys_ck) source
         * can be HSI_CK, CSI_CK, HSE_CK or pll1_p_ck
         */
        source = readl(&regs->cfgr) & RCC_CFGR_SW_MASK;
        switch (source) {
        case RCC_CFGR_SW_PLL1:
                sysclk = stm32_get_PLL1_rate(regs, PLL1_P_CK);
                break;
        case RCC_CFGR_SW_HSE:
                sysclk = stm32_get_rate(regs, HSE);
                break;

        case RCC_CFGR_SW_CSI:
                sysclk = stm32_get_rate(regs, CSI);
                break;

        case RCC_CFGR_SW_HSI:
                sysclk = stm32_get_rate(regs, HSI);
                break;
        }

        /* sysclk = 0 ? no need to go ahead */
        if (!sysclk)
                return sysclk;

        debug("%s system clock: source = %d freq = %ld\n",
              __func__, source, sysclk);

        d1cfgr = readl(&regs->d1cfgr);

        if (d1cfgr & RCC_D1CFGR_D1CPRE_DIVIDED) {
                /* get D1 domain Core prescaler */
                idx = (d1cfgr & RCC_D1CFGR_D1CPRE_DIVIDER) >>
                      RCC_D1CFGR_D1CPRE_SHIFT;
                sysclk = sysclk / prescaler_table[idx];
        }

        if (d1cfgr & RCC_D1CFGR_HPRE_DIVIDED) {
                /* get D1 domain AHB prescaler */
                idx = d1cfgr & RCC_D1CFGR_HPRE_DIVIDER;
                sysclk = sysclk / prescaler_table[idx];
        }

        gate_offset = clk_map[clk->id].gate_offset;

        debug("%s clk->id=%ld gate_offset=0x%x sysclk=%ld\n",
              __func__, clk->id, gate_offset, sysclk);

        switch (gate_offset) {
        case RCC_AHB3ENR:
        case RCC_AHB1ENR:
        case RCC_AHB2ENR:
        case RCC_AHB4ENR:
                return sysclk;
                break;

        case RCC_APB3ENR:
                if (d1cfgr & RCC_D1CFGR_D1PPRE_DIVIDED) {
                        /* get D1 domain APB3 prescaler */
                        idx = (d1cfgr & RCC_D1CFGR_D1PPRE_DIVIDER) >>
                              RCC_D1CFGR_D1PPRE_SHIFT;
                        sysclk = sysclk / prescaler_table[idx];
                }

                debug("%s system clock: freq after APB3 prescaler = %ld\n",
                      __func__, sysclk);

                return sysclk;
                break;

        case RCC_APB4ENR:
                if (d1cfgr & RCC_D3CFGR_D3PPRE_DIVIDED) {
                        /* get D3 domain APB4 prescaler */
                        idx = (d1cfgr & RCC_D3CFGR_D3PPRE_DIVIDER) >>
                              RCC_D3CFGR_D3PPRE_SHIFT;
                        sysclk = sysclk / prescaler_table[idx];
                }

                debug("%s system clock: freq after APB4 prescaler = %ld\n",
                      __func__, sysclk);

                return sysclk;
                break;

        case RCC_APB1LENR:
        case RCC_APB1HENR:
                if (d1cfgr & RCC_D2CFGR_D2PPRE1_DIVIDED) {
                        /* get D2 domain APB1 prescaler */
                        idx = (d1cfgr & RCC_D2CFGR_D2PPRE1_DIVIDER) >>
                              RCC_D2CFGR_D2PPRE1_SHIFT;
                        sysclk = sysclk / prescaler_table[idx];
                }

                debug("%s system clock: freq after APB1 prescaler = %ld\n",
                      __func__, sysclk);

                return sysclk;
                break;

        case RCC_APB2ENR:
                if (d1cfgr & RCC_D2CFGR_D2PPRE2_DIVIDED) {
                        /* get D2 domain APB1 prescaler */
                        idx = (d1cfgr & RCC_D2CFGR_D2PPRE2_DIVIDER) >>
                              RCC_D2CFGR_D2PPRE2_SHIFT;
                        sysclk = sysclk / prescaler_table[idx];
                }

                debug("%s system clock: freq after APB2 prescaler = %ld\n",
                      __func__, sysclk);

                return sysclk;
                break;

        default:
                pr_err("unexpected gate_offset value (0x%x)\n", gate_offset);
                return -EINVAL;
                break;
        }
}

static int stm32_clk_enable(struct clk *clk)
{
        struct stm32_clk *priv = dev_get_priv(clk->dev);
        struct stm32_rcc_regs *regs = priv->rcc_base;
        u32 gate_offset;
        u32 gate_bit_index;
        unsigned long clk_id = clk->id;

        gate_offset = clk_map[clk_id].gate_offset;
        gate_bit_index = clk_map[clk_id].gate_bit_idx;

        debug("%s: clkid=%ld gate offset=0x%x bit_index=%d name=%s\n",
              __func__, clk->id, gate_offset, gate_bit_index,
              clk_map[clk_id].name);

        setbits_le32(&regs->cr + (gate_offset / 4), BIT(gate_bit_index));

        return 0;
}

static int stm32_clk_probe(struct udevice *dev)
{
        struct stm32_clk *priv = dev_get_priv(dev);
        struct udevice *syscon;
        fdt_addr_t addr;
        int err;

        addr = dev_read_addr(dev);
        if (addr == FDT_ADDR_T_NONE)
                return -EINVAL;

        priv->rcc_base = (struct stm32_rcc_regs *)addr;

        /* get corresponding syscon phandle */
        err = uclass_get_device_by_phandle(UCLASS_SYSCON, dev,
                                           "st,syscfg", &syscon);

        if (err) {
                pr_err("unable to find syscon device\n");
                return err;
        }

        priv->pwr_regmap = syscon_get_regmap(syscon);
        if (!priv->pwr_regmap) {
                pr_err("unable to find regmap\n");
                return -ENODEV;
        }

        configure_clocks(dev);

        return 0;
}

static int stm32_clk_of_xlate(struct clk *clk,
                        struct ofnode_phandle_args *args)
{
        if (args->args_count != 1) {
                debug("Invaild args_count: %d\n", args->args_count);
                return -EINVAL;
        }

        if (args->args_count) {
                clk->id = args->args[0];
                /*
                 * this computation convert DT clock index which is used to
                 * point into 2 separate clock arrays (peripheral and kernel
                 * clocks bank) (see include/dt-bindings/clock/stm32h7-clks.h)
                 * into index to point into only one array where peripheral
                 * and kernel clocks are consecutive
                 */
                if (clk->id >= KERN_BANK) {
                        clk->id -= KERN_BANK;
                        clk->id += LAST_PERIF_BANK - PERIF_BANK + 1;
                } else {
                        clk->id -= PERIF_BANK;
                }
        } else {
                clk->id = 0;
        }

        debug("%s clk->id %ld\n", __func__, clk->id);

        return 0;
}

static struct clk_ops stm32_clk_ops = {
        .of_xlate       = stm32_clk_of_xlate,
        .enable         = stm32_clk_enable,
        .get_rate       = stm32_clk_get_rate,
};

U_BOOT_DRIVER(stm32h7_clk) = {
        .name                   = "stm32h7_rcc_clock",
        .id                     = UCLASS_CLK,
        .ops                    = &stm32_clk_ops,
        .probe                  = stm32_clk_probe,
        .priv_auto_alloc_size   = sizeof(struct stm32_clk),
        .flags                  = DM_FLAG_PRE_RELOC,
};