drivers/phy/intel/phy-intel-keembay-emmc.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Intel Keem Bay eMMC PHY driver
  * Copyright (C) 2020 Intel Corporation
  */

 #include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>

 /* eMMC/SD/SDIO core/phy configuration registers */
 #define PHY_CFG_0		0x24
 #define  SEL_DLY_TXCLK_MASK	BIT(29)
 #define  OTAP_DLY_ENA_MASK	BIT(27)
 #define  OTAP_DLY_SEL_MASK	GENMASK(26, 23)
 #define  DLL_EN_MASK		BIT(10)
 #define  PWR_DOWN_MASK		BIT(0)

 #define PHY_CFG_2		0x2c
 #define  SEL_FREQ_MASK		GENMASK(12, 10)

 #define PHY_STAT		0x40
 #define  CAL_DONE_MASK		BIT(6)
 #define  IS_CALDONE(x)		((x) & CAL_DONE_MASK)
 #define  DLL_RDY_MASK		BIT(5)
 #define  IS_DLLRDY(x)		((x) & DLL_RDY_MASK)

 /* From ACS_eMMC51_16nFFC_RO1100_Userguide_v1p0.pdf p17 */
 #define FREQSEL_200M_170M	0x0
 #define FREQSEL_170M_140M	0x1
 #define FREQSEL_140M_110M	0x2
 #define FREQSEL_110M_80M	0x3
 #define FREQSEL_80M_50M		0x4

 struct keembay_emmc_phy {
 	struct regmap *syscfg;
 	struct clk *emmcclk;
 };

 static const struct regmap_config keembay_regmap_config = {
 	.reg_bits = 32,
 	.val_bits = 32,
 	.reg_stride = 4,
 };

 static int keembay_emmc_phy_power(struct phy *phy, bool on_off)
 {
 	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
 	unsigned int caldone;
 	unsigned int dllrdy;
 	unsigned int freqsel;
 	unsigned int mhz;
 	int ret;

 	/*
 	 * Keep phyctrl_pdb and phyctrl_endll low to allow
 	 * initialization of CALIO state M/C DFFs
 	 */
 	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, PWR_DOWN_MASK,
 				 FIELD_PREP(PWR_DOWN_MASK, 0));
 	if (ret) {
 		dev_err(&phy->dev, "CALIO power down bar failed: %d\n", ret);
 		return ret;
 	}

 	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, DLL_EN_MASK,
 				 FIELD_PREP(DLL_EN_MASK, 0));
 	if (ret) {
 		dev_err(&phy->dev, "turn off the dll failed: %d\n", ret);
 		return ret;
 	}

 	/* Already finish power off above */
 	if (!on_off)
 		return 0;

 	mhz = DIV_ROUND_CLOSEST(clk_get_rate(priv->emmcclk), 1000000);
 	if (mhz <= 200 && mhz >= 170)
 		freqsel = FREQSEL_200M_170M;
 	else if (mhz <= 170 && mhz >= 140)
 		freqsel = FREQSEL_170M_140M;
 	else if (mhz <= 140 && mhz >= 110)
 		freqsel = FREQSEL_140M_110M;
 	else if (mhz <= 110 && mhz >= 80)
 		freqsel = FREQSEL_110M_80M;
 	else if (mhz <= 80 && mhz >= 50)
 		freqsel = FREQSEL_80M_50M;
 	else
 		freqsel = 0x0;

 	/* Check for EMMC clock rate*/
 	if (mhz > 175)
 		dev_warn(&phy->dev, "Unsupported rate: %d MHz\n", mhz);

 	/*
 	 * According to the user manual, calpad calibration
 	 * cycle takes more than 2us without the minimal recommended
 	 * value, so we may need a little margin here
 	 */
 	udelay(5);

 	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, PWR_DOWN_MASK,
 				 FIELD_PREP(PWR_DOWN_MASK, 1));
 	if (ret) {
 		dev_err(&phy->dev, "CALIO power down bar failed: %d\n", ret);
 		return ret;
 	}

 	/*
 	 * According to the user manual, it asks driver to wait 5us for
 	 * calpad busy trimming. However it is documented that this value is
 	 * PVT(A.K.A. process, voltage and temperature) relevant, so some
 	 * failure cases are found which indicates we should be more tolerant
 	 * to calpad busy trimming.
 	 */
 	ret = regmap_read_poll_timeout(priv->syscfg, PHY_STAT,
 				       caldone, IS_CALDONE(caldone),
 				       0, 50);
 	if (ret) {
 		dev_err(&phy->dev, "caldone failed, ret=%d\n", ret);
 		return ret;
 	}

 	/* Set the frequency of the DLL operation */
 	ret = regmap_update_bits(priv->syscfg, PHY_CFG_2, SEL_FREQ_MASK,
 				 FIELD_PREP(SEL_FREQ_MASK, freqsel));
 	if (ret) {
 		dev_err(&phy->dev, "set the frequency of dll failed:%d\n", ret);
 		return ret;
 	}

 	/* Turn on the DLL */
 	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, DLL_EN_MASK,
 				 FIELD_PREP(DLL_EN_MASK, 1));
 	if (ret) {
 		dev_err(&phy->dev, "turn on the dll failed: %d\n", ret);
 		return ret;
 	}

 	/*
 	 * We turned on the DLL even though the rate was 0 because we the
 	 * clock might be turned on later.  ...but we can't wait for the DLL
 	 * to lock when the rate is 0 because it will never lock with no
 	 * input clock.
 	 *
 	 * Technically we should be checking the lock later when the clock
 	 * is turned on, but for now we won't.
 	 */
 	if (mhz == 0)
 		return 0;

 	/*
 	 * After enabling analog DLL circuits docs say that we need 10.2 us if
 	 * our source clock is at 50 MHz and that lock time scales linearly
 	 * with clock speed. If we are powering on the PHY and the card clock
 	 * is super slow (like 100kHz) this could take as long as 5.1 ms as
 	 * per the math: 10.2 us * (50000000 Hz / 100000 Hz) => 5.1 ms
 	 * hopefully we won't be running at 100 kHz, but we should still make
 	 * sure we wait long enough.
 	 *
 	 * NOTE: There appear to be corner cases where the DLL seems to take
 	 * extra long to lock for reasons that aren't understood. In some
 	 * extreme cases we've seen it take up to over 10ms (!). We'll be
 	 * generous and give it 50ms.
 	 */
 	ret = regmap_read_poll_timeout(priv->syscfg, PHY_STAT,
 				       dllrdy, IS_DLLRDY(dllrdy),
 				       0, 50 * USEC_PER_MSEC);
 	if (ret)
 		dev_err(&phy->dev, "dllrdy failed, ret=%d\n", ret);

 	return ret;
 }

 static int keembay_emmc_phy_init(struct phy *phy)
 {
 	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);

 	/*
 	 * We purposely get the clock here and not in probe to avoid the
 	 * circular dependency problem. We expect:
 	 * - PHY driver to probe
 	 * - SDHCI driver to start probe
 	 * - SDHCI driver to register it's clock
 	 * - SDHCI driver to get the PHY
 	 * - SDHCI driver to init the PHY
 	 *
 	 * The clock is optional, so upon any error just return it like
 	 * any other error to user.
 	 */
 	priv->emmcclk = clk_get_optional(&phy->dev, "emmcclk");

 	return PTR_ERR_OR_ZERO(priv->emmcclk);
 }

 static int keembay_emmc_phy_exit(struct phy *phy)
 {
 	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);

 	clk_put(priv->emmcclk);

 	return 0;
 };

 static int keembay_emmc_phy_power_on(struct phy *phy)
 {
 	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
 	int ret;

 	/* Delay chain based txclk: enable */
 	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, SEL_DLY_TXCLK_MASK,
 				 FIELD_PREP(SEL_DLY_TXCLK_MASK, 1));
 	if (ret) {
 		dev_err(&phy->dev, "ERROR: delay chain txclk set: %d\n", ret);
 		return ret;
 	}

 	/* Output tap delay: enable */
 	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, OTAP_DLY_ENA_MASK,
 				 FIELD_PREP(OTAP_DLY_ENA_MASK, 1));
 	if (ret) {
 		dev_err(&phy->dev, "ERROR: output tap delay set: %d\n", ret);
 		return ret;
 	}

 	/* Output tap delay */
 	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, OTAP_DLY_SEL_MASK,
 				 FIELD_PREP(OTAP_DLY_SEL_MASK, 2));
 	if (ret) {
 		dev_err(&phy->dev, "ERROR: output tap delay select: %d\n", ret);
 		return ret;
 	}

 	/* Power up eMMC phy analog blocks */
 	return keembay_emmc_phy_power(phy, true);
 }

 static int keembay_emmc_phy_power_off(struct phy *phy)
 {
 	/* Power down eMMC phy analog blocks */
 	return keembay_emmc_phy_power(phy, false);
 }

 static const struct phy_ops ops = {
 	.init		= keembay_emmc_phy_init,
 	.exit		= keembay_emmc_phy_exit,
 	.power_on	= keembay_emmc_phy_power_on,
 	.power_off	= keembay_emmc_phy_power_off,
 	.owner		= THIS_MODULE,
 };

 static int keembay_emmc_phy_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	struct keembay_emmc_phy *priv;
 	struct phy *generic_phy;
 	struct phy_provider *phy_provider;
 	void __iomem *base;

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

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

 	priv->syscfg = devm_regmap_init_mmio(dev, base, &keembay_regmap_config);
 	if (IS_ERR(priv->syscfg))
 		return PTR_ERR(priv->syscfg);

 	generic_phy = devm_phy_create(dev, np, &ops);
 	if (IS_ERR(generic_phy))
 		return dev_err_probe(dev, PTR_ERR(generic_phy),
 				     "failed to create PHY\n");

 	phy_set_drvdata(generic_phy, priv);
 	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);

 	return PTR_ERR_OR_ZERO(phy_provider);
 }

 static const struct of_device_id keembay_emmc_phy_dt_ids[] = {
 	{ .compatible = "intel,keembay-emmc-phy" },
 	{}
 };
 MODULE_DEVICE_TABLE(of, keembay_emmc_phy_dt_ids);

 static struct platform_driver keembay_emmc_phy_driver = {
 	.probe		= keembay_emmc_phy_probe,
 	.driver		= {
 		.name	= "keembay-emmc-phy",
 		.of_match_table = keembay_emmc_phy_dt_ids,
 	},
 };
 module_platform_driver(keembay_emmc_phy_driver);

 MODULE_AUTHOR("Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>");
 MODULE_DESCRIPTION("Intel Keem Bay eMMC PHY driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Intel Keem Bay eMMC PHY driver
	* Copyright (C) 2020 Intel Corporation
	*/

	#include <linux/bitfield.h>
	#include <linux/clk.h>
	#include <linux/delay.h>
	#include <linux/mfd/syscon.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/phy/phy.h>
	#include <linux/platform_device.h>
	#include <linux/regmap.h>

	/* eMMC/SD/SDIO core/phy configuration registers */
	#define PHY_CFG_0 0x24
	#define SEL_DLY_TXCLK_MASK BIT(29)
	#define OTAP_DLY_ENA_MASK BIT(27)
	#define OTAP_DLY_SEL_MASK GENMASK(26, 23)
	#define DLL_EN_MASK BIT(10)
	#define PWR_DOWN_MASK BIT(0)

	#define PHY_CFG_2 0x2c
	#define SEL_FREQ_MASK GENMASK(12, 10)

	#define PHY_STAT 0x40
	#define CAL_DONE_MASK BIT(6)
	#define IS_CALDONE(x) ((x) & CAL_DONE_MASK)
	#define DLL_RDY_MASK BIT(5)
	#define IS_DLLRDY(x) ((x) & DLL_RDY_MASK)

	/* From ACS_eMMC51_16nFFC_RO1100_Userguide_v1p0.pdf p17 */
	#define FREQSEL_200M_170M 0x0
	#define FREQSEL_170M_140M 0x1
	#define FREQSEL_140M_110M 0x2
	#define FREQSEL_110M_80M 0x3
	#define FREQSEL_80M_50M 0x4

	struct keembay_emmc_phy {
	struct regmap *syscfg;
	struct clk *emmcclk;
	};

	static const struct regmap_config keembay_regmap_config = {
	.reg_bits = 32,
	.val_bits = 32,
	.reg_stride = 4,
	};

	static int keembay_emmc_phy_power(struct phy *phy, bool on_off)
	{
	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
	unsigned int caldone;
	unsigned int dllrdy;
	unsigned int freqsel;
	unsigned int mhz;
	int ret;

	/*
	* Keep phyctrl_pdb and phyctrl_endll low to allow
	* initialization of CALIO state M/C DFFs
	*/
	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, PWR_DOWN_MASK,
	FIELD_PREP(PWR_DOWN_MASK, 0));
	if (ret) {
	dev_err(&phy->dev, "CALIO power down bar failed: %d\n", ret);
	return ret;
	}

	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, DLL_EN_MASK,
	FIELD_PREP(DLL_EN_MASK, 0));
	if (ret) {
	dev_err(&phy->dev, "turn off the dll failed: %d\n", ret);
	return ret;
	}

	/* Already finish power off above */
	if (!on_off)
	return 0;

	mhz = DIV_ROUND_CLOSEST(clk_get_rate(priv->emmcclk), 1000000);
	if (mhz <= 200 && mhz >= 170)
	freqsel = FREQSEL_200M_170M;
	else if (mhz <= 170 && mhz >= 140)
	freqsel = FREQSEL_170M_140M;
	else if (mhz <= 140 && mhz >= 110)
	freqsel = FREQSEL_140M_110M;
	else if (mhz <= 110 && mhz >= 80)
	freqsel = FREQSEL_110M_80M;
	else if (mhz <= 80 && mhz >= 50)
	freqsel = FREQSEL_80M_50M;
	else
	freqsel = 0x0;

	/* Check for EMMC clock rate*/
	if (mhz > 175)
	dev_warn(&phy->dev, "Unsupported rate: %d MHz\n", mhz);

	/*
	* According to the user manual, calpad calibration
	* cycle takes more than 2us without the minimal recommended
	* value, so we may need a little margin here
	*/
	udelay(5);

	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, PWR_DOWN_MASK,
	FIELD_PREP(PWR_DOWN_MASK, 1));
	if (ret) {
	dev_err(&phy->dev, "CALIO power down bar failed: %d\n", ret);
	return ret;
	}

	/*
	* According to the user manual, it asks driver to wait 5us for
	* calpad busy trimming. However it is documented that this value is
	* PVT(A.K.A. process, voltage and temperature) relevant, so some
	* failure cases are found which indicates we should be more tolerant
	* to calpad busy trimming.
	*/
	ret = regmap_read_poll_timeout(priv->syscfg, PHY_STAT,
	caldone, IS_CALDONE(caldone),
	0, 50);
	if (ret) {
	dev_err(&phy->dev, "caldone failed, ret=%d\n", ret);
	return ret;
	}

	/* Set the frequency of the DLL operation */
	ret = regmap_update_bits(priv->syscfg, PHY_CFG_2, SEL_FREQ_MASK,
	FIELD_PREP(SEL_FREQ_MASK, freqsel));
	if (ret) {
	dev_err(&phy->dev, "set the frequency of dll failed:%d\n", ret);
	return ret;
	}

	/* Turn on the DLL */
	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, DLL_EN_MASK,
	FIELD_PREP(DLL_EN_MASK, 1));
	if (ret) {
	dev_err(&phy->dev, "turn on the dll failed: %d\n", ret);
	return ret;
	}

	/*
	* We turned on the DLL even though the rate was 0 because we the
	* clock might be turned on later. ...but we can't wait for the DLL
	* to lock when the rate is 0 because it will never lock with no
	* input clock.
	*
	* Technically we should be checking the lock later when the clock
	* is turned on, but for now we won't.
	*/
	if (mhz == 0)
	return 0;

	/*
	* After enabling analog DLL circuits docs say that we need 10.2 us if
	* our source clock is at 50 MHz and that lock time scales linearly
	* with clock speed. If we are powering on the PHY and the card clock
	* is super slow (like 100kHz) this could take as long as 5.1 ms as
	* per the math: 10.2 us * (50000000 Hz / 100000 Hz) => 5.1 ms
	* hopefully we won't be running at 100 kHz, but we should still make
	* sure we wait long enough.
	*
	* NOTE: There appear to be corner cases where the DLL seems to take
	* extra long to lock for reasons that aren't understood. In some
	* extreme cases we've seen it take up to over 10ms (!). We'll be
	* generous and give it 50ms.
	*/
	ret = regmap_read_poll_timeout(priv->syscfg, PHY_STAT,
	dllrdy, IS_DLLRDY(dllrdy),
	0, 50 * USEC_PER_MSEC);
	if (ret)
	dev_err(&phy->dev, "dllrdy failed, ret=%d\n", ret);

	return ret;
	}

	static int keembay_emmc_phy_init(struct phy *phy)
	{
	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);

	/*
	* We purposely get the clock here and not in probe to avoid the
	* circular dependency problem. We expect:
	* - PHY driver to probe
	* - SDHCI driver to start probe
	* - SDHCI driver to register it's clock
	* - SDHCI driver to get the PHY
	* - SDHCI driver to init the PHY
	*
	* The clock is optional, so upon any error just return it like
	* any other error to user.
	*/
	priv->emmcclk = clk_get_optional(&phy->dev, "emmcclk");

	return PTR_ERR_OR_ZERO(priv->emmcclk);
	}

	static int keembay_emmc_phy_exit(struct phy *phy)
	{
	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);

	clk_put(priv->emmcclk);

	return 0;
	};

	static int keembay_emmc_phy_power_on(struct phy *phy)
	{
	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
	int ret;

	/* Delay chain based txclk: enable */
	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, SEL_DLY_TXCLK_MASK,
	FIELD_PREP(SEL_DLY_TXCLK_MASK, 1));
	if (ret) {
	dev_err(&phy->dev, "ERROR: delay chain txclk set: %d\n", ret);
	return ret;
	}

	/* Output tap delay: enable */
	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, OTAP_DLY_ENA_MASK,
	FIELD_PREP(OTAP_DLY_ENA_MASK, 1));
	if (ret) {
	dev_err(&phy->dev, "ERROR: output tap delay set: %d\n", ret);
	return ret;
	}

	/* Output tap delay */
	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, OTAP_DLY_SEL_MASK,
	FIELD_PREP(OTAP_DLY_SEL_MASK, 2));
	if (ret) {
	dev_err(&phy->dev, "ERROR: output tap delay select: %d\n", ret);
	return ret;
	}

	/* Power up eMMC phy analog blocks */
	return keembay_emmc_phy_power(phy, true);
	}

	static int keembay_emmc_phy_power_off(struct phy *phy)
	{
	/* Power down eMMC phy analog blocks */
	return keembay_emmc_phy_power(phy, false);
	}

	static const struct phy_ops ops = {
	.init = keembay_emmc_phy_init,
	.exit = keembay_emmc_phy_exit,
	.power_on = keembay_emmc_phy_power_on,
	.power_off = keembay_emmc_phy_power_off,
	.owner = THIS_MODULE,
	};

	static int keembay_emmc_phy_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct keembay_emmc_phy *priv;
	struct phy *generic_phy;
	struct phy_provider *phy_provider;
	void __iomem *base;

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

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

	priv->syscfg = devm_regmap_init_mmio(dev, base, &keembay_regmap_config);
	if (IS_ERR(priv->syscfg))
	return PTR_ERR(priv->syscfg);

	generic_phy = devm_phy_create(dev, np, &ops);
	if (IS_ERR(generic_phy))
	return dev_err_probe(dev, PTR_ERR(generic_phy),
	"failed to create PHY\n");

	phy_set_drvdata(generic_phy, priv);
	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);

	return PTR_ERR_OR_ZERO(phy_provider);
	}

	static const struct of_device_id keembay_emmc_phy_dt_ids[] = {
	{ .compatible = "intel,keembay-emmc-phy" },
	{}
	};
	MODULE_DEVICE_TABLE(of, keembay_emmc_phy_dt_ids);

	static struct platform_driver keembay_emmc_phy_driver = {
	.probe = keembay_emmc_phy_probe,
	.driver = {
	.name = "keembay-emmc-phy",
	.of_match_table = keembay_emmc_phy_dt_ids,
	},
	};
	module_platform_driver(keembay_emmc_phy_driver);

	MODULE_AUTHOR("Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>");
	MODULE_DESCRIPTION("Intel Keem Bay eMMC PHY driver");
	MODULE_LICENSE("GPL v2");