xref: /linux/drivers/phy/st/phy-stm32-combophy.c (revision 6fcb22ef50b47959e17012be57dcad0fdca8d237)

// SPDX-License-Identifier: GPL-2.0-only
/*
 * STMicroelectronics COMBOPHY STM32MP25 Controller driver.
 *
 * Copyright (C) 2024 STMicroelectronics
 * Author: Christian Bruel <christian.bruel@foss.st.com>
 */

#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/mfd/syscon.h>
#include <linux/platform_device.h>
#include <linux/phy/phy.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#include <dt-bindings/phy/phy.h>

#define SYSCFG_COMBOPHY_CR1 0x4c00
#define SYSCFG_COMBOPHY_CR2 0x4c04
#define SYSCFG_COMBOPHY_CR4 0x4c0c
#define SYSCFG_COMBOPHY_CR5 0x4c10
#define SYSCFG_COMBOPHY_SR  0x4c14
#define SYSCFG_PCIEPRGCR    0x6080

/* SYSCFG PCIEPRGCR */
#define STM32MP25_PCIEPRGCR_EN	  BIT(0)
#define STM32MP25_PCIEPRG_IMPCTRL_OHM     GENMASK(3, 1)
#define STM32MP25_PCIEPRG_IMPCTRL_VSWING  GENMASK(5, 4)

/* SYSCFG SYSCFG_COMBOPHY_SR */
#define STM32MP25_PIPE0_PHYSTATUS BIT(1)

/* SYSCFG CR1 */
#define SYSCFG_COMBOPHY_CR1_REFUSEPAD BIT(0)
#define SYSCFG_COMBOPHY_CR1_MPLLMULT GENMASK(7, 1)
#define SYSCFG_COMBOPHY_CR1_REFCLKSEL GENMASK(16, 8)
#define SYSCFG_COMBOPHY_CR1_REFCLKDIV2 BIT(17)
#define SYSCFG_COMBOPHY_CR1_REFSSPEN BIT(18)
#define SYSCFG_COMBOPHY_CR1_SSCEN BIT(19)

/* SYSCFG CR4 */
#define SYSCFG_COMBOPHY_CR4_RX0_EQ GENMASK(2, 0)

#define MPLLMULT_19_2 (0x02u << 1)
#define MPLLMULT_20   (0x7du << 1)
#define MPLLMULT_24   (0x68u << 1)
#define MPLLMULT_25   (0x64u << 1)
#define MPLLMULT_26   (0x60u << 1)
#define MPLLMULT_38_4 (0x41u << 1)
#define MPLLMULT_48   (0x6cu << 1)
#define MPLLMULT_50   (0x32u << 1)
#define MPLLMULT_52   (0x30u << 1)
#define MPLLMULT_100  (0x19u << 1)

#define REFCLKSEL_0   0
#define REFCLKSEL_1   (0x108u << 8)

#define REFCLDIV_0    0

/* SYSCFG CR2 */
#define SYSCFG_COMBOPHY_CR2_MODESEL GENMASK(1, 0)
#define SYSCFG_COMBOPHY_CR2_ISO_DIS BIT(15)

#define COMBOPHY_MODESEL_PCIE 0
#define COMBOPHY_MODESEL_USB  3

/* SYSCFG CR5 */
#define SYSCFG_COMBOPHY_CR5_COMMON_CLOCKS BIT(12)

#define COMBOPHY_SUP_ANA_MPLL_LOOP_CTL 0xc0
#define COMBOPHY_PROP_CNTRL GENMASK(7, 4)

/* Required apb/ker clocks first, optional pad last. */
static const char * const combophy_clks[] = {"apb", "ker", "pad"};
#define APB_CLK 0
#define KER_CLK 1
#define PAD_CLK 2

struct stm32_combophy {
	struct phy *phy;
	struct regmap *regmap;
	struct device *dev;
	void __iomem *base;
	struct reset_control *phy_reset;
	struct clk_bulk_data clks[ARRAY_SIZE(combophy_clks)];
	int num_clks;
	bool have_pad_clk;
	unsigned int type;
	bool is_init;
	int irq_wakeup;
};

struct clk_impedance  {
	u32 microohm;
	u32 vswing[4];
};

/*
 * lookup table to hold the settings needed for a ref clock frequency
 * impedance, the offset is used to set the IMP_CTL and DE_EMP bit of the
 * PRG_IMP_CTRL register. Use ordered discrete values in the table
 */
static const struct clk_impedance imp_lookup[] = {
	{ 6090000, { 442000, 564000, 684000, 802000 } },
	{ 5662000, { 528000, 621000, 712000, 803000 } },
	{ 5292000, { 491000, 596000, 700000, 802000 } },
	{ 4968000, { 558000, 640000, 722000, 803000 } },
	{ 4684000, { 468000, 581000, 692000, 802000 } },
	{ 4429000, { 554000, 613000, 717000, 803000 } },
	{ 4204000, { 511000, 609000, 706000, 802000 } },
	{ 3999000, { 571000, 648000, 726000, 803000 } }
};

static int stm32_impedance_tune(struct stm32_combophy *combophy)
{
	u8 imp_size = ARRAY_SIZE(imp_lookup);
	u8 vswing_size = ARRAY_SIZE(imp_lookup[0].vswing);
	u8 imp_of, vswing_of;
	u32 max_imp = imp_lookup[0].microohm;
	u32 min_imp = imp_lookup[imp_size - 1].microohm;
	u32 max_vswing = imp_lookup[imp_size - 1].vswing[vswing_size - 1];
	u32 min_vswing = imp_lookup[0].vswing[0];
	u32 val;
	u32 regval;

	if (!of_property_read_u32(combophy->dev->of_node, "st,output-micro-ohms", &val)) {
		if (val < min_imp || val > max_imp) {
			dev_err(combophy->dev, "Invalid value %u for output ohm\n", val);
			return -EINVAL;
		}

		regval = 0;
		for (imp_of = 0; imp_of < ARRAY_SIZE(imp_lookup); imp_of++) {
			if (imp_lookup[imp_of].microohm <= val) {
				regval = FIELD_PREP(STM32MP25_PCIEPRG_IMPCTRL_OHM, imp_of);
				break;
			}
		}

		dev_dbg(combophy->dev, "Set %u micro-ohms output impedance\n",
			imp_lookup[imp_of].microohm);

		regmap_update_bits(combophy->regmap, SYSCFG_PCIEPRGCR,
				   STM32MP25_PCIEPRG_IMPCTRL_OHM,
				   regval);
	} else {
		regmap_read(combophy->regmap, SYSCFG_PCIEPRGCR, &val);
		imp_of = FIELD_GET(STM32MP25_PCIEPRG_IMPCTRL_OHM, val);
	}

	if (!of_property_read_u32(combophy->dev->of_node, "st,output-vswing-microvolt", &val)) {
		if (val < min_vswing || val > max_vswing) {
			dev_err(combophy->dev, "Invalid value %u for output vswing\n", val);
			return -EINVAL;
		}

		regval = 0;
		for (vswing_of = 0; vswing_of < ARRAY_SIZE(imp_lookup[imp_of].vswing); vswing_of++) {
			if (imp_lookup[imp_of].vswing[vswing_of] >= val) {
				regval = FIELD_PREP(STM32MP25_PCIEPRG_IMPCTRL_VSWING, vswing_of);
				break;
			}
		}

		dev_dbg(combophy->dev, "Set %u microvolt swing\n",
			 imp_lookup[imp_of].vswing[vswing_of]);

		regmap_update_bits(combophy->regmap, SYSCFG_PCIEPRGCR,
				   STM32MP25_PCIEPRG_IMPCTRL_VSWING,
				   regval);
	}

	return 0;
}

static int stm32_combophy_pll_init(struct stm32_combophy *combophy)
{
	int ret;
	u32 refclksel, pllmult, propcntrl, val;
	u32 clk_rate;
	struct clk *clk;
	u32 cr1_val = 0, cr1_mask = 0;

	if (combophy->have_pad_clk)
		clk = combophy->clks[PAD_CLK].clk;
	else
		clk = combophy->clks[KER_CLK].clk;

	clk_rate = clk_get_rate(clk);

	dev_dbg(combophy->dev, "%s pll init rate %d\n",
		combophy->have_pad_clk ? "External" : "Ker", clk_rate);

	if (combophy->type != PHY_TYPE_PCIE) {
		cr1_mask |= SYSCFG_COMBOPHY_CR1_REFSSPEN;
		cr1_val |= SYSCFG_COMBOPHY_CR1_REFSSPEN;
	}

	if (of_property_present(combophy->dev->of_node, "st,ssc-on")) {
		dev_dbg(combophy->dev, "Enabling clock with SSC\n");
		cr1_mask |= SYSCFG_COMBOPHY_CR1_SSCEN;
		cr1_val |= SYSCFG_COMBOPHY_CR1_SSCEN;
	}

	switch (clk_rate) {
	case 100000000:
		pllmult = MPLLMULT_100;
		refclksel = REFCLKSEL_0;
		propcntrl = 0x8u << 4;
		break;
	case 19200000:
		pllmult = MPLLMULT_19_2;
		refclksel = REFCLKSEL_1;
		propcntrl = 0x8u << 4;
		break;
	case 25000000:
		pllmult = MPLLMULT_25;
		refclksel = REFCLKSEL_0;
		propcntrl = 0xeu << 4;
		break;
	case 24000000:
		pllmult = MPLLMULT_24;
		refclksel = REFCLKSEL_1;
		propcntrl = 0xeu << 4;
		break;
	case 20000000:
		pllmult = MPLLMULT_20;
		refclksel = REFCLKSEL_0;
		propcntrl = 0xeu << 4;
		break;
	default:
		dev_err(combophy->dev, "Invalid rate 0x%x\n", clk_rate);
		return -EINVAL;
	}

	cr1_mask |= SYSCFG_COMBOPHY_CR1_REFCLKDIV2;
	cr1_val |= REFCLDIV_0;

	cr1_mask |= SYSCFG_COMBOPHY_CR1_REFCLKSEL;
	cr1_val |= refclksel;

	cr1_mask |= SYSCFG_COMBOPHY_CR1_MPLLMULT;
	cr1_val |= pllmult;

	/*
	 * vddcombophy is interconnected with vddcore. Isolation bit should be unset
	 * before using the ComboPHY.
	 */
	regmap_update_bits(combophy->regmap, SYSCFG_COMBOPHY_CR2,
			   SYSCFG_COMBOPHY_CR2_ISO_DIS, SYSCFG_COMBOPHY_CR2_ISO_DIS);

	reset_control_assert(combophy->phy_reset);

	if (combophy->type == PHY_TYPE_PCIE) {
		ret = stm32_impedance_tune(combophy);
		if (ret)
			goto out_iso;

		cr1_mask |= SYSCFG_COMBOPHY_CR1_REFUSEPAD;
		cr1_val |= combophy->have_pad_clk ? SYSCFG_COMBOPHY_CR1_REFUSEPAD : 0;
	}

	if (!of_property_read_u32(combophy->dev->of_node, "st,rx-equalizer", &val)) {
		dev_dbg(combophy->dev, "Set RX equalizer %u\n", val);
		if (val > SYSCFG_COMBOPHY_CR4_RX0_EQ) {
			dev_err(combophy->dev, "Invalid value %u for rx0 equalizer\n", val);
			ret = -EINVAL;
			goto out_iso;
		}

		regmap_update_bits(combophy->regmap, SYSCFG_COMBOPHY_CR4,
			   SYSCFG_COMBOPHY_CR4_RX0_EQ, val);
	}

	regmap_update_bits(combophy->regmap, SYSCFG_COMBOPHY_CR1, cr1_mask, cr1_val);

	/*
	 * Force elasticity buffer to be tuned for the reference clock as
	 * the separated clock model is not supported
	 */
	regmap_update_bits(combophy->regmap, SYSCFG_COMBOPHY_CR5,
			   SYSCFG_COMBOPHY_CR5_COMMON_CLOCKS, SYSCFG_COMBOPHY_CR5_COMMON_CLOCKS);

	reset_control_deassert(combophy->phy_reset);

	ret = regmap_read_poll_timeout(combophy->regmap, SYSCFG_COMBOPHY_SR, val,
				       !(val & STM32MP25_PIPE0_PHYSTATUS),
				       10, 1000);
	if (ret) {
		dev_err(combophy->dev, "timeout, cannot lock PLL\n");
		if (combophy->type == PHY_TYPE_PCIE && !combophy->have_pad_clk)
			regmap_update_bits(combophy->regmap, SYSCFG_PCIEPRGCR,
					   STM32MP25_PCIEPRGCR_EN, 0);

		if (combophy->type != PHY_TYPE_PCIE)
			regmap_update_bits(combophy->regmap, SYSCFG_COMBOPHY_CR1,
					   SYSCFG_COMBOPHY_CR1_REFSSPEN, 0);

		goto out;
	}


	if (combophy->type == PHY_TYPE_PCIE) {
		if (!combophy->have_pad_clk)
			regmap_update_bits(combophy->regmap, SYSCFG_PCIEPRGCR,
					   STM32MP25_PCIEPRGCR_EN, STM32MP25_PCIEPRGCR_EN);

		val = readl_relaxed(combophy->base + COMBOPHY_SUP_ANA_MPLL_LOOP_CTL);
		val &= ~COMBOPHY_PROP_CNTRL;
		val |= propcntrl;
		writel_relaxed(val, combophy->base + COMBOPHY_SUP_ANA_MPLL_LOOP_CTL);
	}

	return 0;

out_iso:
	reset_control_deassert(combophy->phy_reset);

out:
	regmap_update_bits(combophy->regmap, SYSCFG_COMBOPHY_CR2,
			   SYSCFG_COMBOPHY_CR2_ISO_DIS, 0);

	return ret;
}

static struct phy *stm32_combophy_xlate(struct device *dev,
					const struct of_phandle_args *args)
{
	struct stm32_combophy *combophy = dev_get_drvdata(dev);
	unsigned int type;

	if (args->args_count != 1) {
		dev_err(dev, "invalid number of cells in 'phy' property\n");
		return ERR_PTR(-EINVAL);
	}

	type = args->args[0];
	if (type != PHY_TYPE_USB3 && type != PHY_TYPE_PCIE) {
		dev_err(dev, "unsupported device type: %d\n", type);
		return ERR_PTR(-EINVAL);
	}

	if (combophy->have_pad_clk && type != PHY_TYPE_PCIE) {
		dev_err(dev, "Invalid use of clk_pad for USB3 mode\n");
		return ERR_PTR(-EINVAL);
	}

	combophy->type = type;

	return combophy->phy;
}

static int stm32_combophy_set_mode(struct stm32_combophy *combophy)
{
	int type = combophy->type;
	u32 val;

	switch (type) {
	case PHY_TYPE_PCIE:
		dev_dbg(combophy->dev, "setting PCIe ComboPHY\n");
		val = COMBOPHY_MODESEL_PCIE;
		break;
	case PHY_TYPE_USB3:
		dev_dbg(combophy->dev, "setting USB3 ComboPHY\n");
		val = COMBOPHY_MODESEL_USB;
		break;
	default:
		dev_err(combophy->dev, "Invalid PHY mode %d\n", type);
		return -EINVAL;
	}

	return regmap_update_bits(combophy->regmap, SYSCFG_COMBOPHY_CR2,
				  SYSCFG_COMBOPHY_CR2_MODESEL, val);
}

static int stm32_combophy_suspend_noirq(struct device *dev)
{
	struct stm32_combophy *combophy = dev_get_drvdata(dev);

	/*
	 * Clocks should be turned off since it is not needed for
	 * wakeup capability. In case usb-remote wakeup is not enabled,
	 * combo-phy is already turned off by HCD driver using exit callback
	 */
	if (combophy->is_init) {
		clk_bulk_disable_unprepare(combophy->num_clks, combophy->clks);

		/* since wakeup is enabled for ctrl */
		enable_irq_wake(combophy->irq_wakeup);
	}

	return 0;
}

static int stm32_combophy_resume_noirq(struct device *dev)
{
	struct stm32_combophy *combophy = dev_get_drvdata(dev);
	int ret;

	/*
	 * If clocks was turned off by suspend call for wakeup then needs
	 * to be turned back ON in resume. In case usb-remote wakeup is not
	 * enabled, clocks already turned ON by HCD driver using init callback
	 */
	if (combophy->is_init) {
		/* since wakeup was enabled for ctrl */
		disable_irq_wake(combophy->irq_wakeup);

		ret = clk_bulk_prepare_enable(combophy->num_clks, combophy->clks);
		if (ret) {
			dev_err(dev, "can't enable clocks (%d)\n", ret);
			return ret;
		}
	}

	return 0;
}

static int stm32_combophy_exit(struct phy *phy)
{
	struct stm32_combophy *combophy = phy_get_drvdata(phy);
	struct device *dev = combophy->dev;

	combophy->is_init = false;

	if (combophy->type == PHY_TYPE_PCIE && !combophy->have_pad_clk)
		regmap_update_bits(combophy->regmap, SYSCFG_PCIEPRGCR,
				   STM32MP25_PCIEPRGCR_EN, 0);

	if (combophy->type != PHY_TYPE_PCIE)
		regmap_update_bits(combophy->regmap, SYSCFG_COMBOPHY_CR1,
				   SYSCFG_COMBOPHY_CR1_REFSSPEN, 0);

	regmap_update_bits(combophy->regmap, SYSCFG_COMBOPHY_CR2,
			   SYSCFG_COMBOPHY_CR2_ISO_DIS, 0);

	clk_bulk_disable_unprepare(combophy->num_clks, combophy->clks);

	pm_runtime_put_noidle(dev);

	return 0;
}

static int stm32_combophy_init(struct phy *phy)
{
	struct stm32_combophy *combophy = phy_get_drvdata(phy);
	struct device *dev = combophy->dev;
	int ret;

	pm_runtime_get_noresume(dev);

	ret = clk_bulk_prepare_enable(combophy->num_clks, combophy->clks);
	if (ret) {
		dev_err(dev, "can't enable clocks (%d)\n", ret);
		pm_runtime_put_noidle(dev);
		return ret;
	}

	ret = stm32_combophy_set_mode(combophy);
	if (ret) {
		dev_err(dev, "combophy mode not set\n");
		clk_bulk_disable_unprepare(combophy->num_clks, combophy->clks);
		pm_runtime_put_noidle(dev);
		return ret;
	}

	ret = stm32_combophy_pll_init(combophy);
	if (ret) {
		clk_bulk_disable_unprepare(combophy->num_clks, combophy->clks);
		pm_runtime_put_noidle(dev);
		return ret;
	}

	pm_runtime_disable(dev);
	pm_runtime_set_active(dev);
	pm_runtime_enable(dev);

	combophy->is_init = true;

	return ret;
}

static const struct phy_ops stm32_combophy_phy_data = {
	.init = stm32_combophy_init,
	.exit = stm32_combophy_exit,
	.owner = THIS_MODULE
};

static irqreturn_t stm32_combophy_irq_wakeup_handler(int irq, void *dev_id)
{
	return IRQ_HANDLED;
}

static int stm32_combophy_get_clocks(struct stm32_combophy *combophy)
{
	int i, ret;

	for (i = 0; i < ARRAY_SIZE(combophy_clks); i++)
		combophy->clks[i].id = combophy_clks[i];

	combophy->num_clks = ARRAY_SIZE(combophy_clks) - 1;

	ret = devm_clk_bulk_get(combophy->dev, combophy->num_clks, combophy->clks);
	if (ret)
		return ret;

	ret = devm_clk_bulk_get_optional(combophy->dev, 1, combophy->clks + combophy->num_clks);
	if (ret)
		return ret;

	if (combophy->clks[combophy->num_clks].clk != NULL) {
		combophy->have_pad_clk = true;
		combophy->num_clks++;
	}

	return 0;
}

static int stm32_combophy_probe(struct platform_device *pdev)
{
	struct stm32_combophy *combophy;
	struct device *dev = &pdev->dev;
	struct phy_provider *phy_provider;
	int ret, irq;

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

	combophy->dev = dev;

	dev_set_drvdata(dev, combophy);

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

	ret = stm32_combophy_get_clocks(combophy);
	if (ret)
		return ret;

	combophy->phy_reset = devm_reset_control_get_exclusive(dev, "phy");
	if (IS_ERR(combophy->phy_reset))
		return dev_err_probe(dev, PTR_ERR(combophy->phy_reset),
				     "Failed to get PHY reset\n");

	combophy->regmap = syscon_regmap_lookup_by_compatible("st,stm32mp25-syscfg");
	if (IS_ERR(combophy->regmap))
		return dev_err_probe(dev, PTR_ERR(combophy->regmap),
				     "No syscfg specified\n");

	combophy->phy = devm_phy_create(dev, NULL, &stm32_combophy_phy_data);
	if (IS_ERR(combophy->phy))
		return dev_err_probe(dev, PTR_ERR(combophy->phy),
				     "failed to create PCIe/USB3 ComboPHY\n");

	if (device_property_read_bool(dev, "wakeup-source")) {
		irq = platform_get_irq(pdev, 0);
		if (irq < 0)
			return dev_err_probe(dev, irq, "failed to get IRQ\n");
		combophy->irq_wakeup = irq;

		ret = devm_request_threaded_irq(dev, combophy->irq_wakeup, NULL,
						stm32_combophy_irq_wakeup_handler, IRQF_ONESHOT,
						NULL, NULL);
		if (ret)
			return dev_err_probe(dev, ret, "unable to request wake IRQ %d\n",
						 combophy->irq_wakeup);
	}

	ret = devm_pm_runtime_enable(dev);
	if (ret)
		return dev_err_probe(dev, ret, "Failed to enable pm runtime\n");

	phy_set_drvdata(combophy->phy, combophy);

	phy_provider = devm_of_phy_provider_register(dev, stm32_combophy_xlate);

	return PTR_ERR_OR_ZERO(phy_provider);
}

static const struct dev_pm_ops stm32_combophy_pm_ops = {
	NOIRQ_SYSTEM_SLEEP_PM_OPS(stm32_combophy_suspend_noirq,
				  stm32_combophy_resume_noirq)
};

static const struct of_device_id stm32_combophy_of_match[] = {
	{ .compatible = "st,stm32mp25-combophy", },
	{ },
};
MODULE_DEVICE_TABLE(of, stm32_combophy_of_match);

static struct platform_driver stm32_combophy_driver = {
	.probe = stm32_combophy_probe,
	.driver = {
		   .name = "stm32-combophy",
		   .of_match_table = stm32_combophy_of_match,
		   .pm = pm_sleep_ptr(&stm32_combophy_pm_ops)
	}
};

module_platform_driver(stm32_combophy_driver);

MODULE_AUTHOR("Christian Bruel <christian.bruel@foss.st.com>");
MODULE_DESCRIPTION("STM32MP25 Combophy USB3/PCIe controller driver");
MODULE_LICENSE("GPL");