drivers/clk/clk_stm32f.c - filogic/uboot - Gitiles

 /*
  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
  * Author(s): Vikas Manocha, <vikas.manocha@st.com> for STMicroelectronics.
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */

 #include <common.h>
 #include <clk-uclass.h>
 #include <dm.h>

 #include <asm/io.h>
 #include <asm/arch/stm32.h>
 #include <asm/arch/stm32_periph.h>
 #include <asm/arch/stm32_pwr.h>

 #include <dt-bindings/mfd/stm32f7-rcc.h>

 #define RCC_CR_HSION			BIT(0)
 #define RCC_CR_HSEON			BIT(16)
 #define RCC_CR_HSERDY			BIT(17)
 #define RCC_CR_HSEBYP			BIT(18)
 #define RCC_CR_CSSON			BIT(19)
 #define RCC_CR_PLLON			BIT(24)
 #define RCC_CR_PLLRDY			BIT(25)

 #define RCC_PLLCFGR_PLLM_MASK		GENMASK(5, 0)
 #define RCC_PLLCFGR_PLLN_MASK		GENMASK(14, 6)
 #define RCC_PLLCFGR_PLLP_MASK		GENMASK(17, 16)
 #define RCC_PLLCFGR_PLLQ_MASK		GENMASK(27, 24)
 #define RCC_PLLCFGR_PLLSRC		BIT(22)
 #define RCC_PLLCFGR_PLLM_SHIFT		0
 #define RCC_PLLCFGR_PLLN_SHIFT		6
 #define RCC_PLLCFGR_PLLP_SHIFT		16
 #define RCC_PLLCFGR_PLLQ_SHIFT		24

 #define RCC_CFGR_AHB_PSC_MASK		GENMASK(7, 4)
 #define RCC_CFGR_APB1_PSC_MASK		GENMASK(12, 10)
 #define RCC_CFGR_APB2_PSC_MASK		GENMASK(15, 13)
 #define RCC_CFGR_SW0			BIT(0)
 #define RCC_CFGR_SW1			BIT(1)
 #define RCC_CFGR_SW_MASK		GENMASK(1, 0)
 #define RCC_CFGR_SW_HSI			0
 #define RCC_CFGR_SW_HSE			RCC_CFGR_SW0
 #define RCC_CFGR_SW_PLL			RCC_CFGR_SW1
 #define RCC_CFGR_SWS0			BIT(2)
 #define RCC_CFGR_SWS1			BIT(3)
 #define RCC_CFGR_SWS_MASK		GENMASK(3, 2)
 #define RCC_CFGR_SWS_HSI		0
 #define RCC_CFGR_SWS_HSE		RCC_CFGR_SWS0
 #define RCC_CFGR_SWS_PLL		RCC_CFGR_SWS1
 #define RCC_CFGR_HPRE_SHIFT		4
 #define RCC_CFGR_PPRE1_SHIFT		10
 #define RCC_CFGR_PPRE2_SHIFT		13

 /*
  * RCC AHB1ENR specific definitions
  */
 #define RCC_AHB1ENR_ETHMAC_EN		BIT(25)
 #define RCC_AHB1ENR_ETHMAC_TX_EN	BIT(26)
 #define RCC_AHB1ENR_ETHMAC_RX_EN	BIT(27)

 /*
  * RCC APB1ENR specific definitions
  */
 #define RCC_APB1ENR_TIM2EN		BIT(0)
 #define RCC_APB1ENR_PWREN		BIT(28)

 /*
  * RCC APB2ENR specific definitions
  */
 #define RCC_APB2ENR_SYSCFGEN		BIT(14)


 struct pll_psc {
 	u8	pll_m;
 	u16	pll_n;
 	u8	pll_p;
 	u8	pll_q;
 	u8	ahb_psc;
 	u8	apb1_psc;
 	u8	apb2_psc;
 };

 #define AHB_PSC_1			0
 #define AHB_PSC_2			0x8
 #define AHB_PSC_4			0x9
 #define AHB_PSC_8			0xA
 #define AHB_PSC_16			0xB
 #define AHB_PSC_64			0xC
 #define AHB_PSC_128			0xD
 #define AHB_PSC_256			0xE
 #define AHB_PSC_512			0xF

 #define APB_PSC_1			0
 #define APB_PSC_2			0x4
 #define APB_PSC_4			0x5
 #define APB_PSC_8			0x6
 #define APB_PSC_16			0x7

 struct stm32_clk_info {
 	struct pll_psc sys_pll_psc;
 	bool has_overdrive;
 };

 struct stm32_clk_info stm32f4_clk_info = {
 	/* 180 MHz */
 	.sys_pll_psc = {
 		.pll_m = 8,
 		.pll_n = 360,
 		.pll_p = 2,
 		.pll_q = 8,
 		.ahb_psc = AHB_PSC_1,
 		.apb1_psc = APB_PSC_4,
 		.apb2_psc = APB_PSC_2,
 	},
 	.has_overdrive = false,
 };

 struct stm32_clk_info stm32f7_clk_info = {
 	/* 200 MHz */
 	.sys_pll_psc = {
 		.pll_m = 25,
 		.pll_n = 400,
 		.pll_p = 2,
 		.pll_q = 8,
 		.ahb_psc = AHB_PSC_1,
 		.apb1_psc = APB_PSC_4,
 		.apb2_psc = APB_PSC_2,
 	},
 	.has_overdrive = true,
 };

 struct stm32_clk {
 	struct stm32_rcc_regs *base;
 	struct stm32_pwr_regs *pwr_regs;
 	struct stm32_clk_info *info;
 };

 static int configure_clocks(struct udevice *dev)
 {
 	struct stm32_clk *priv = dev_get_priv(dev);
 	struct stm32_rcc_regs *regs = priv->base;
 	struct stm32_pwr_regs *pwr = priv->pwr_regs;
 	struct pll_psc sys_pll_psc = priv->info->sys_pll_psc;

 	/* Reset RCC configuration */
 	setbits_le32(&regs->cr, RCC_CR_HSION);
 	writel(0, &regs->cfgr); /* Reset CFGR */
 	clrbits_le32(&regs->cr, (RCC_CR_HSEON | RCC_CR_CSSON
 		| RCC_CR_PLLON));
 	writel(0x24003010, &regs->pllcfgr); /* Reset value from RM */
 	clrbits_le32(&regs->cr, RCC_CR_HSEBYP);
 	writel(0, &regs->cir); /* Disable all interrupts */

 	/* Configure for HSE+PLL operation */
 	setbits_le32(&regs->cr, RCC_CR_HSEON);
 	while (!(readl(&regs->cr) & RCC_CR_HSERDY))
 		;

 	setbits_le32(&regs->cfgr, ((
 		sys_pll_psc.ahb_psc << RCC_CFGR_HPRE_SHIFT)
 		| (sys_pll_psc.apb1_psc << RCC_CFGR_PPRE1_SHIFT)
 		| (sys_pll_psc.apb2_psc << RCC_CFGR_PPRE2_SHIFT)));

 	/* Configure the main PLL */
 	setbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLSRC); /* pll source HSE */
 	clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLM_MASK,
 			sys_pll_psc.pll_m << RCC_PLLCFGR_PLLM_SHIFT);
 	clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLN_MASK,
 			sys_pll_psc.pll_n << RCC_PLLCFGR_PLLN_SHIFT);
 	clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLP_MASK,
 			((sys_pll_psc.pll_p >> 1) - 1) << RCC_PLLCFGR_PLLP_SHIFT);
 	clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLQ_MASK,
 			sys_pll_psc.pll_q << RCC_PLLCFGR_PLLQ_SHIFT);

 	/* Enable the main PLL */
 	setbits_le32(&regs->cr, RCC_CR_PLLON);
 	while (!(readl(&regs->cr) & RCC_CR_PLLRDY))
 		;

 	setbits_le32(&regs->apb1enr, RCC_APB1ENR_PWREN);

 	if (priv->info->has_overdrive) {
 		/*
 		 * Enable high performance mode
 		 * System frequency up to 200 MHz
 		 */
 		setbits_le32(&pwr->cr1, PWR_CR1_ODEN);
 		/* Infinite wait! */
 		while (!(readl(&pwr->csr1) & PWR_CSR1_ODRDY))
 			;
 		/* Enable the Over-drive switch */
 		setbits_le32(&pwr->cr1, PWR_CR1_ODSWEN);
 		/* Infinite wait! */
 		while (!(readl(&pwr->csr1) & PWR_CSR1_ODSWRDY))
 			;
 	}

 	stm32_flash_latency_cfg(5);
 	clrbits_le32(&regs->cfgr, (RCC_CFGR_SW0 | RCC_CFGR_SW1));
 	setbits_le32(&regs->cfgr, RCC_CFGR_SW_PLL);

 	while ((readl(&regs->cfgr) & RCC_CFGR_SWS_MASK) !=
 			RCC_CFGR_SWS_PLL)
 		;

 	return 0;
 }

 static unsigned long stm32_clk_get_rate(struct clk *clk)
 {
 	struct stm32_clk *priv = dev_get_priv(clk->dev);
 	struct stm32_rcc_regs *regs = priv->base;
 	u32 sysclk = 0;
 	u32 shift = 0;
 	u16 pllm, plln, pllp;
 	/* Prescaler table lookups for clock computation */
 	u8 ahb_psc_table[16] = {
 		0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9
 	};
 	u8 apb_psc_table[8] = {
 		0, 0, 0, 0, 1, 2, 3, 4
 	};

 	if ((readl(&regs->cfgr) & RCC_CFGR_SWS_MASK) ==
 			RCC_CFGR_SWS_PLL) {
 		pllm = (readl(&regs->pllcfgr) & RCC_PLLCFGR_PLLM_MASK);
 		plln = ((readl(&regs->pllcfgr) & RCC_PLLCFGR_PLLN_MASK)
 			>> RCC_PLLCFGR_PLLN_SHIFT);
 		pllp = ((((readl(&regs->pllcfgr) & RCC_PLLCFGR_PLLP_MASK)
 			>> RCC_PLLCFGR_PLLP_SHIFT) + 1) << 1);
 		sysclk = ((CONFIG_STM32_HSE_HZ / pllm) * plln) / pllp;
 	} else {
 		return -EINVAL;
 	}

 	switch (clk->id) {
 	/*
 	 * AHB CLOCK: 3 x 32 bits consecutive registers are used :
 	 * AHB1, AHB2 and AHB3
 	 */
 	case STM32F7_AHB1_CLOCK(GPIOA) ... STM32F7_AHB3_CLOCK(QSPI):
 		shift = ahb_psc_table[(
 			(readl(&regs->cfgr) & RCC_CFGR_AHB_PSC_MASK)
 			>> RCC_CFGR_HPRE_SHIFT)];
 		return sysclk >>= shift;
 	/* APB1 CLOCK */
 	case STM32F7_APB1_CLOCK(TIM2) ... STM32F7_APB1_CLOCK(UART8):
 		shift = apb_psc_table[(
 			(readl(&regs->cfgr) & RCC_CFGR_APB1_PSC_MASK)
 			>> RCC_CFGR_PPRE1_SHIFT)];
 		return sysclk >>= shift;
 	/* APB2 CLOCK */
 	case STM32F7_APB2_CLOCK(TIM1) ... STM32F7_APB2_CLOCK(LTDC):
 		shift = apb_psc_table[(
 			(readl(&regs->cfgr) & RCC_CFGR_APB2_PSC_MASK)
 			>> RCC_CFGR_PPRE2_SHIFT)];
 		return sysclk >>= shift;
 	default:
 		pr_err("clock index %ld out of range\n", clk->id);
 		return -EINVAL;
 	}
 }

 static int stm32_clk_enable(struct clk *clk)
 {
 	struct stm32_clk *priv = dev_get_priv(clk->dev);
 	struct stm32_rcc_regs *regs = priv->base;
 	u32 offset = clk->id / 32;
 	u32 bit_index = clk->id % 32;

 	debug("%s: clkid = %ld, offset from AHB1ENR is %d, bit_index = %d\n",
 	      __func__, clk->id, offset, bit_index);
 	setbits_le32(&regs->ahb1enr + offset, BIT(bit_index));

 	return 0;
 }

 void clock_setup(int peripheral)
 {
 	switch (peripheral) {
 	case SYSCFG_CLOCK_CFG:
 		setbits_le32(&STM32_RCC->apb2enr, RCC_APB2ENR_SYSCFGEN);
 		break;
 	case TIMER2_CLOCK_CFG:
 		setbits_le32(&STM32_RCC->apb1enr, RCC_APB1ENR_TIM2EN);
 		break;
 	case STMMAC_CLOCK_CFG:
 		setbits_le32(&STM32_RCC->ahb1enr, RCC_AHB1ENR_ETHMAC_EN);
 		setbits_le32(&STM32_RCC->ahb1enr, RCC_AHB1ENR_ETHMAC_RX_EN);
 		setbits_le32(&STM32_RCC->ahb1enr, RCC_AHB1ENR_ETHMAC_TX_EN);
 		break;
 	default:
 		break;
 	}
 }

 static int stm32_clk_probe(struct udevice *dev)
 {
 	struct ofnode_phandle_args args;
 	int err;

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

 	struct stm32_clk *priv = dev_get_priv(dev);
 	fdt_addr_t addr;

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

 	priv->base = (struct stm32_rcc_regs *)addr;
 	priv->info = (struct stm32_clk_info *)dev_get_driver_data(dev);

 	if (priv->info->has_overdrive) {
 		err = dev_read_phandle_with_args(dev, "st,syscfg", NULL, 0, 0,
 						 &args);
 		if (err) {
 			debug("%s: can't find syscon device (%d)\n", __func__,
 			      err);
 			return err;
 		}

 		priv->pwr_regs = (struct stm32_pwr_regs *)ofnode_get_addr(args.node);
 	}

 	configure_clocks(dev);

 	return 0;
 }

 static int stm32_clk_of_xlate(struct clk *clk, struct ofnode_phandle_args *args)
 {
 	debug("%s(clk=%p)\n", __func__, clk);

 	if (args->args_count != 2) {
 		debug("Invaild args_count: %d\n", args->args_count);
 		return -EINVAL;
 	}

 	if (args->args_count)
 		clk->id = args->args[1];
 	else
 		clk->id = 0;

 	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,
 };

 static const struct udevice_id stm32_clk_ids[] = {
 	{ .compatible = "st,stm32f42xx-rcc", .data = (ulong)&stm32f4_clk_info},
 	{ .compatible = "st,stm32f746-rcc", .data = (ulong)&stm32f7_clk_info},
 	{}
 };

 U_BOOT_DRIVER(stm32fx_clk) = {
 	.name			= "stm32fx_clk",
 	.id			= UCLASS_CLK,
 	.of_match		= stm32_clk_ids,
 	.ops			= &stm32_clk_ops,
 	.probe			= stm32_clk_probe,
 	.priv_auto_alloc_size	= sizeof(struct stm32_clk),
 	.flags			= DM_FLAG_PRE_RELOC,
 };
	/*
	* Copyright (C) 2017, STMicroelectronics - All Rights Reserved
	* Author(s): Vikas Manocha, <vikas.manocha@st.com> for STMicroelectronics.
	*
	* SPDX-License-Identifier: GPL-2.0+
	*/

	#include <common.h>
	#include <clk-uclass.h>
	#include <dm.h>

	#include <asm/io.h>
	#include <asm/arch/stm32.h>
	#include <asm/arch/stm32_periph.h>
	#include <asm/arch/stm32_pwr.h>

	#include <dt-bindings/mfd/stm32f7-rcc.h>

	#define RCC_CR_HSION BIT(0)
	#define RCC_CR_HSEON BIT(16)
	#define RCC_CR_HSERDY BIT(17)
	#define RCC_CR_HSEBYP BIT(18)
	#define RCC_CR_CSSON BIT(19)
	#define RCC_CR_PLLON BIT(24)
	#define RCC_CR_PLLRDY BIT(25)

	#define RCC_PLLCFGR_PLLM_MASK GENMASK(5, 0)
	#define RCC_PLLCFGR_PLLN_MASK GENMASK(14, 6)
	#define RCC_PLLCFGR_PLLP_MASK GENMASK(17, 16)
	#define RCC_PLLCFGR_PLLQ_MASK GENMASK(27, 24)
	#define RCC_PLLCFGR_PLLSRC BIT(22)
	#define RCC_PLLCFGR_PLLM_SHIFT 0
	#define RCC_PLLCFGR_PLLN_SHIFT 6
	#define RCC_PLLCFGR_PLLP_SHIFT 16
	#define RCC_PLLCFGR_PLLQ_SHIFT 24

	#define RCC_CFGR_AHB_PSC_MASK GENMASK(7, 4)
	#define RCC_CFGR_APB1_PSC_MASK GENMASK(12, 10)
	#define RCC_CFGR_APB2_PSC_MASK GENMASK(15, 13)
	#define RCC_CFGR_SW0 BIT(0)
	#define RCC_CFGR_SW1 BIT(1)
	#define RCC_CFGR_SW_MASK GENMASK(1, 0)
	#define RCC_CFGR_SW_HSI 0
	#define RCC_CFGR_SW_HSE RCC_CFGR_SW0
	#define RCC_CFGR_SW_PLL RCC_CFGR_SW1
	#define RCC_CFGR_SWS0 BIT(2)
	#define RCC_CFGR_SWS1 BIT(3)
	#define RCC_CFGR_SWS_MASK GENMASK(3, 2)
	#define RCC_CFGR_SWS_HSI 0
	#define RCC_CFGR_SWS_HSE RCC_CFGR_SWS0
	#define RCC_CFGR_SWS_PLL RCC_CFGR_SWS1
	#define RCC_CFGR_HPRE_SHIFT 4
	#define RCC_CFGR_PPRE1_SHIFT 10
	#define RCC_CFGR_PPRE2_SHIFT 13

	/*
	* RCC AHB1ENR specific definitions
	*/
	#define RCC_AHB1ENR_ETHMAC_EN BIT(25)
	#define RCC_AHB1ENR_ETHMAC_TX_EN BIT(26)
	#define RCC_AHB1ENR_ETHMAC_RX_EN BIT(27)

	/*
	* RCC APB1ENR specific definitions
	*/
	#define RCC_APB1ENR_TIM2EN BIT(0)
	#define RCC_APB1ENR_PWREN BIT(28)

	/*
	* RCC APB2ENR specific definitions
	*/
	#define RCC_APB2ENR_SYSCFGEN BIT(14)


	struct pll_psc {
	u8 pll_m;
	u16 pll_n;
	u8 pll_p;
	u8 pll_q;
	u8 ahb_psc;
	u8 apb1_psc;
	u8 apb2_psc;
	};

	#define AHB_PSC_1 0
	#define AHB_PSC_2 0x8
	#define AHB_PSC_4 0x9
	#define AHB_PSC_8 0xA
	#define AHB_PSC_16 0xB
	#define AHB_PSC_64 0xC
	#define AHB_PSC_128 0xD
	#define AHB_PSC_256 0xE
	#define AHB_PSC_512 0xF

	#define APB_PSC_1 0
	#define APB_PSC_2 0x4
	#define APB_PSC_4 0x5
	#define APB_PSC_8 0x6
	#define APB_PSC_16 0x7

	struct stm32_clk_info {
	struct pll_psc sys_pll_psc;
	bool has_overdrive;
	};

	struct stm32_clk_info stm32f4_clk_info = {
	/* 180 MHz */
	.sys_pll_psc = {
	.pll_m = 8,
	.pll_n = 360,
	.pll_p = 2,
	.pll_q = 8,
	.ahb_psc = AHB_PSC_1,
	.apb1_psc = APB_PSC_4,
	.apb2_psc = APB_PSC_2,
	},
	.has_overdrive = false,
	};

	struct stm32_clk_info stm32f7_clk_info = {
	/* 200 MHz */
	.sys_pll_psc = {
	.pll_m = 25,
	.pll_n = 400,
	.pll_p = 2,
	.pll_q = 8,
	.ahb_psc = AHB_PSC_1,
	.apb1_psc = APB_PSC_4,
	.apb2_psc = APB_PSC_2,
	},
	.has_overdrive = true,
	};

	struct stm32_clk {
	struct stm32_rcc_regs *base;
	struct stm32_pwr_regs *pwr_regs;
	struct stm32_clk_info *info;
	};

	static int configure_clocks(struct udevice *dev)
	{
	struct stm32_clk *priv = dev_get_priv(dev);
	struct stm32_rcc_regs *regs = priv->base;
	struct stm32_pwr_regs *pwr = priv->pwr_regs;
	struct pll_psc sys_pll_psc = priv->info->sys_pll_psc;

	/* Reset RCC configuration */
	setbits_le32(&regs->cr, RCC_CR_HSION);
	writel(0, &regs->cfgr); /* Reset CFGR */
	clrbits_le32(&regs->cr, (RCC_CR_HSEON \| RCC_CR_CSSON
	\| RCC_CR_PLLON));
	writel(0x24003010, &regs->pllcfgr); /* Reset value from RM */
	clrbits_le32(&regs->cr, RCC_CR_HSEBYP);
	writel(0, &regs->cir); /* Disable all interrupts */

	/* Configure for HSE+PLL operation */
	setbits_le32(&regs->cr, RCC_CR_HSEON);
	while (!(readl(&regs->cr) & RCC_CR_HSERDY))
	;

	setbits_le32(&regs->cfgr, ((
	sys_pll_psc.ahb_psc << RCC_CFGR_HPRE_SHIFT)
	\| (sys_pll_psc.apb1_psc << RCC_CFGR_PPRE1_SHIFT)
	\| (sys_pll_psc.apb2_psc << RCC_CFGR_PPRE2_SHIFT)));

	/* Configure the main PLL */
	setbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLSRC); /* pll source HSE */
	clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLM_MASK,
	sys_pll_psc.pll_m << RCC_PLLCFGR_PLLM_SHIFT);
	clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLN_MASK,
	sys_pll_psc.pll_n << RCC_PLLCFGR_PLLN_SHIFT);
	clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLP_MASK,
	((sys_pll_psc.pll_p >> 1) - 1) << RCC_PLLCFGR_PLLP_SHIFT);
	clrsetbits_le32(&regs->pllcfgr, RCC_PLLCFGR_PLLQ_MASK,
	sys_pll_psc.pll_q << RCC_PLLCFGR_PLLQ_SHIFT);

	/* Enable the main PLL */
	setbits_le32(&regs->cr, RCC_CR_PLLON);
	while (!(readl(&regs->cr) & RCC_CR_PLLRDY))
	;

	setbits_le32(&regs->apb1enr, RCC_APB1ENR_PWREN);

	if (priv->info->has_overdrive) {
	/*
	* Enable high performance mode
	* System frequency up to 200 MHz
	*/
	setbits_le32(&pwr->cr1, PWR_CR1_ODEN);
	/* Infinite wait! */
	while (!(readl(&pwr->csr1) & PWR_CSR1_ODRDY))
	;
	/* Enable the Over-drive switch */
	setbits_le32(&pwr->cr1, PWR_CR1_ODSWEN);
	/* Infinite wait! */
	while (!(readl(&pwr->csr1) & PWR_CSR1_ODSWRDY))
	;
	}

	stm32_flash_latency_cfg(5);
	clrbits_le32(&regs->cfgr, (RCC_CFGR_SW0 \| RCC_CFGR_SW1));
	setbits_le32(&regs->cfgr, RCC_CFGR_SW_PLL);

	while ((readl(&regs->cfgr) & RCC_CFGR_SWS_MASK) !=
	RCC_CFGR_SWS_PLL)
	;

	return 0;
	}

	static unsigned long stm32_clk_get_rate(struct clk *clk)
	{
	struct stm32_clk *priv = dev_get_priv(clk->dev);
	struct stm32_rcc_regs *regs = priv->base;
	u32 sysclk = 0;
	u32 shift = 0;
	u16 pllm, plln, pllp;
	/* Prescaler table lookups for clock computation */
	u8 ahb_psc_table[16] = {
	0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9
	};
	u8 apb_psc_table[8] = {
	0, 0, 0, 0, 1, 2, 3, 4
	};

	if ((readl(&regs->cfgr) & RCC_CFGR_SWS_MASK) ==
	RCC_CFGR_SWS_PLL) {
	pllm = (readl(&regs->pllcfgr) & RCC_PLLCFGR_PLLM_MASK);
	plln = ((readl(&regs->pllcfgr) & RCC_PLLCFGR_PLLN_MASK)
	>> RCC_PLLCFGR_PLLN_SHIFT);
	pllp = ((((readl(&regs->pllcfgr) & RCC_PLLCFGR_PLLP_MASK)
	>> RCC_PLLCFGR_PLLP_SHIFT) + 1) << 1);
	sysclk = ((CONFIG_STM32_HSE_HZ / pllm) * plln) / pllp;
	} else {
	return -EINVAL;
	}

	switch (clk->id) {
	/*
	* AHB CLOCK: 3 x 32 bits consecutive registers are used :
	* AHB1, AHB2 and AHB3
	*/
	case STM32F7_AHB1_CLOCK(GPIOA) ... STM32F7_AHB3_CLOCK(QSPI):
	shift = ahb_psc_table[(
	(readl(&regs->cfgr) & RCC_CFGR_AHB_PSC_MASK)
	>> RCC_CFGR_HPRE_SHIFT)];
	return sysclk >>= shift;
	/* APB1 CLOCK */
	case STM32F7_APB1_CLOCK(TIM2) ... STM32F7_APB1_CLOCK(UART8):
	shift = apb_psc_table[(
	(readl(&regs->cfgr) & RCC_CFGR_APB1_PSC_MASK)
	>> RCC_CFGR_PPRE1_SHIFT)];
	return sysclk >>= shift;
	/* APB2 CLOCK */
	case STM32F7_APB2_CLOCK(TIM1) ... STM32F7_APB2_CLOCK(LTDC):
	shift = apb_psc_table[(
	(readl(&regs->cfgr) & RCC_CFGR_APB2_PSC_MASK)
	>> RCC_CFGR_PPRE2_SHIFT)];
	return sysclk >>= shift;
	default:
	pr_err("clock index %ld out of range\n", clk->id);
	return -EINVAL;
	}
	}

	static int stm32_clk_enable(struct clk *clk)
	{
	struct stm32_clk *priv = dev_get_priv(clk->dev);
	struct stm32_rcc_regs *regs = priv->base;
	u32 offset = clk->id / 32;
	u32 bit_index = clk->id % 32;

	debug("%s: clkid = %ld, offset from AHB1ENR is %d, bit_index = %d\n",
	__func__, clk->id, offset, bit_index);
	setbits_le32(&regs->ahb1enr + offset, BIT(bit_index));

	return 0;
	}

	void clock_setup(int peripheral)
	{
	switch (peripheral) {
	case SYSCFG_CLOCK_CFG:
	setbits_le32(&STM32_RCC->apb2enr, RCC_APB2ENR_SYSCFGEN);
	break;
	case TIMER2_CLOCK_CFG:
	setbits_le32(&STM32_RCC->apb1enr, RCC_APB1ENR_TIM2EN);
	break;
	case STMMAC_CLOCK_CFG:
	setbits_le32(&STM32_RCC->ahb1enr, RCC_AHB1ENR_ETHMAC_EN);
	setbits_le32(&STM32_RCC->ahb1enr, RCC_AHB1ENR_ETHMAC_RX_EN);
	setbits_le32(&STM32_RCC->ahb1enr, RCC_AHB1ENR_ETHMAC_TX_EN);
	break;
	default:
	break;
	}
	}

	static int stm32_clk_probe(struct udevice *dev)
	{
	struct ofnode_phandle_args args;
	int err;

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

	struct stm32_clk *priv = dev_get_priv(dev);
	fdt_addr_t addr;

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

	priv->base = (struct stm32_rcc_regs *)addr;
	priv->info = (struct stm32_clk_info *)dev_get_driver_data(dev);

	if (priv->info->has_overdrive) {
	err = dev_read_phandle_with_args(dev, "st,syscfg", NULL, 0, 0,
	&args);
	if (err) {
	debug("%s: can't find syscon device (%d)\n", __func__,
	err);
	return err;
	}

	priv->pwr_regs = (struct stm32_pwr_regs *)ofnode_get_addr(args.node);
	}

	configure_clocks(dev);

	return 0;
	}

	static int stm32_clk_of_xlate(struct clk clk, struct ofnode_phandle_args args)
	{
	debug("%s(clk=%p)\n", __func__, clk);

	if (args->args_count != 2) {
	debug("Invaild args_count: %d\n", args->args_count);
	return -EINVAL;
	}

	if (args->args_count)
	clk->id = args->args[1];
	else
	clk->id = 0;

	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,
	};

	static const struct udevice_id stm32_clk_ids[] = {
	{ .compatible = "st,stm32f42xx-rcc", .data = (ulong)&stm32f4_clk_info},
	{ .compatible = "st,stm32f746-rcc", .data = (ulong)&stm32f7_clk_info},
	{}
	};

	U_BOOT_DRIVER(stm32fx_clk) = {
	.name = "stm32fx_clk",
	.id = UCLASS_CLK,
	.of_match = stm32_clk_ids,
	.ops = &stm32_clk_ops,
	.probe = stm32_clk_probe,
	.priv_auto_alloc_size = sizeof(struct stm32_clk),
	.flags = DM_FLAG_PRE_RELOC,
	};