xref: /openbmc/linux/drivers/phy/cadence/cdns-dphy.c (revision efcd5f52)

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright: 2017-2018 Cadence Design Systems, Inc.
 */

#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/reset.h>

#include <linux/phy/phy.h>
#include <linux/phy/phy-mipi-dphy.h>

#define REG_WAKEUP_TIME_NS		800
#define DPHY_PLL_RATE_HZ		108000000

/* DPHY registers */
#define DPHY_PMA_CMN(reg)		(reg)
#define DPHY_PMA_LCLK(reg)		(0x100 + (reg))
#define DPHY_PMA_LDATA(lane, reg)	(0x200 + ((lane) * 0x100) + (reg))
#define DPHY_PMA_RCLK(reg)		(0x600 + (reg))
#define DPHY_PMA_RDATA(lane, reg)	(0x700 + ((lane) * 0x100) + (reg))
#define DPHY_PCS(reg)			(0xb00 + (reg))

#define DPHY_CMN_SSM			DPHY_PMA_CMN(0x20)
#define DPHY_CMN_SSM_EN			BIT(0)
#define DPHY_CMN_TX_MODE_EN		BIT(9)

#define DPHY_CMN_PWM			DPHY_PMA_CMN(0x40)
#define DPHY_CMN_PWM_DIV(x)		((x) << 20)
#define DPHY_CMN_PWM_LOW(x)		((x) << 10)
#define DPHY_CMN_PWM_HIGH(x)		(x)

#define DPHY_CMN_FBDIV			DPHY_PMA_CMN(0x4c)
#define DPHY_CMN_FBDIV_VAL(low, high)	(((high) << 11) | ((low) << 22))
#define DPHY_CMN_FBDIV_FROM_REG		(BIT(10) | BIT(21))

#define DPHY_CMN_OPIPDIV		DPHY_PMA_CMN(0x50)
#define DPHY_CMN_IPDIV_FROM_REG		BIT(0)
#define DPHY_CMN_IPDIV(x)		((x) << 1)
#define DPHY_CMN_OPDIV_FROM_REG		BIT(6)
#define DPHY_CMN_OPDIV(x)		((x) << 7)

#define DPHY_BAND_CFG			DPHY_PCS(0x0)
#define DPHY_BAND_CFG_LEFT_BAND		GENMASK(4, 0)
#define DPHY_BAND_CFG_RIGHT_BAND	GENMASK(9, 5)

#define DPHY_PSM_CFG			DPHY_PCS(0x4)
#define DPHY_PSM_CFG_FROM_REG		BIT(0)
#define DPHY_PSM_CLK_DIV(x)		((x) << 1)

#define DSI_HBP_FRAME_OVERHEAD		12
#define DSI_HSA_FRAME_OVERHEAD		14
#define DSI_HFP_FRAME_OVERHEAD		6
#define DSI_HSS_VSS_VSE_FRAME_OVERHEAD	4
#define DSI_BLANKING_FRAME_OVERHEAD	6
#define DSI_NULL_FRAME_OVERHEAD		6
#define DSI_EOT_PKT_SIZE		4

struct cdns_dphy_cfg {
	u8 pll_ipdiv;
	u8 pll_opdiv;
	u16 pll_fbdiv;
	unsigned int nlanes;
};

enum cdns_dphy_clk_lane_cfg {
	DPHY_CLK_CFG_LEFT_DRIVES_ALL = 0,
	DPHY_CLK_CFG_LEFT_DRIVES_RIGHT = 1,
	DPHY_CLK_CFG_LEFT_DRIVES_LEFT = 2,
	DPHY_CLK_CFG_RIGHT_DRIVES_ALL = 3,
};

struct cdns_dphy;
struct cdns_dphy_ops {
	int (*probe)(struct cdns_dphy *dphy);
	void (*remove)(struct cdns_dphy *dphy);
	void (*set_psm_div)(struct cdns_dphy *dphy, u8 div);
	void (*set_clk_lane_cfg)(struct cdns_dphy *dphy,
				 enum cdns_dphy_clk_lane_cfg cfg);
	void (*set_pll_cfg)(struct cdns_dphy *dphy,
			    const struct cdns_dphy_cfg *cfg);
	unsigned long (*get_wakeup_time_ns)(struct cdns_dphy *dphy);
};

struct cdns_dphy {
	struct cdns_dphy_cfg cfg;
	void __iomem *regs;
	struct clk *psm_clk;
	struct clk *pll_ref_clk;
	const struct cdns_dphy_ops *ops;
	struct phy *phy;
};

/* Order of bands is important since the index is the band number. */
static const unsigned int tx_bands[] = {
	80, 100, 120, 160, 200, 240, 320, 390, 450, 510, 560, 640, 690, 770,
	870, 950, 1000, 1200, 1400, 1600, 1800, 2000, 2200, 2500
};

static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy,
				     struct cdns_dphy_cfg *cfg,
				     struct phy_configure_opts_mipi_dphy *opts,
				     unsigned int *dsi_hfp_ext)
{
	unsigned long pll_ref_hz = clk_get_rate(dphy->pll_ref_clk);
	u64 dlane_bps;

	memset(cfg, 0, sizeof(*cfg));

	if (pll_ref_hz < 9600000 || pll_ref_hz >= 150000000)
		return -EINVAL;
	else if (pll_ref_hz < 19200000)
		cfg->pll_ipdiv = 1;
	else if (pll_ref_hz < 38400000)
		cfg->pll_ipdiv = 2;
	else if (pll_ref_hz < 76800000)
		cfg->pll_ipdiv = 4;
	else
		cfg->pll_ipdiv = 8;

	dlane_bps = opts->hs_clk_rate;

	if (dlane_bps > 2500000000UL || dlane_bps < 160000000UL)
		return -EINVAL;
	else if (dlane_bps >= 1250000000)
		cfg->pll_opdiv = 1;
	else if (dlane_bps >= 630000000)
		cfg->pll_opdiv = 2;
	else if (dlane_bps >= 320000000)
		cfg->pll_opdiv = 4;
	else if (dlane_bps >= 160000000)
		cfg->pll_opdiv = 8;

	cfg->pll_fbdiv = DIV_ROUND_UP_ULL(dlane_bps * 2 * cfg->pll_opdiv *
					  cfg->pll_ipdiv,
					  pll_ref_hz);

	return 0;
}

static int cdns_dphy_setup_psm(struct cdns_dphy *dphy)
{
	unsigned long psm_clk_hz = clk_get_rate(dphy->psm_clk);
	unsigned long psm_div;

	if (!psm_clk_hz || psm_clk_hz > 100000000)
		return -EINVAL;

	psm_div = DIV_ROUND_CLOSEST(psm_clk_hz, 1000000);
	if (dphy->ops->set_psm_div)
		dphy->ops->set_psm_div(dphy, psm_div);

	return 0;
}

static void cdns_dphy_set_clk_lane_cfg(struct cdns_dphy *dphy,
				       enum cdns_dphy_clk_lane_cfg cfg)
{
	if (dphy->ops->set_clk_lane_cfg)
		dphy->ops->set_clk_lane_cfg(dphy, cfg);
}

static void cdns_dphy_set_pll_cfg(struct cdns_dphy *dphy,
				  const struct cdns_dphy_cfg *cfg)
{
	if (dphy->ops->set_pll_cfg)
		dphy->ops->set_pll_cfg(dphy, cfg);
}

static unsigned long cdns_dphy_get_wakeup_time_ns(struct cdns_dphy *dphy)
{
	return dphy->ops->get_wakeup_time_ns(dphy);
}

static unsigned long cdns_dphy_ref_get_wakeup_time_ns(struct cdns_dphy *dphy)
{
	/* Default wakeup time is 800 ns (in a simulated environment). */
	return 800;
}

static void cdns_dphy_ref_set_pll_cfg(struct cdns_dphy *dphy,
				      const struct cdns_dphy_cfg *cfg)
{
	u32 fbdiv_low, fbdiv_high;

	fbdiv_low = (cfg->pll_fbdiv / 4) - 2;
	fbdiv_high = cfg->pll_fbdiv - fbdiv_low - 2;

	writel(DPHY_CMN_IPDIV_FROM_REG | DPHY_CMN_OPDIV_FROM_REG |
	       DPHY_CMN_IPDIV(cfg->pll_ipdiv) |
	       DPHY_CMN_OPDIV(cfg->pll_opdiv),
	       dphy->regs + DPHY_CMN_OPIPDIV);
	writel(DPHY_CMN_FBDIV_FROM_REG |
	       DPHY_CMN_FBDIV_VAL(fbdiv_low, fbdiv_high),
	       dphy->regs + DPHY_CMN_FBDIV);
	writel(DPHY_CMN_PWM_HIGH(6) | DPHY_CMN_PWM_LOW(0x101) |
	       DPHY_CMN_PWM_DIV(0x8),
	       dphy->regs + DPHY_CMN_PWM);
}

static void cdns_dphy_ref_set_psm_div(struct cdns_dphy *dphy, u8 div)
{
	writel(DPHY_PSM_CFG_FROM_REG | DPHY_PSM_CLK_DIV(div),
	       dphy->regs + DPHY_PSM_CFG);
}

/*
 * This is the reference implementation of DPHY hooks. Specific integration of
 * this IP may have to re-implement some of them depending on how they decided
 * to wire things in the SoC.
 */
static const struct cdns_dphy_ops ref_dphy_ops = {
	.get_wakeup_time_ns = cdns_dphy_ref_get_wakeup_time_ns,
	.set_pll_cfg = cdns_dphy_ref_set_pll_cfg,
	.set_psm_div = cdns_dphy_ref_set_psm_div,
};

static int cdns_dphy_config_from_opts(struct phy *phy,
				      struct phy_configure_opts_mipi_dphy *opts,
				      struct cdns_dphy_cfg *cfg)
{
	struct cdns_dphy *dphy = phy_get_drvdata(phy);
	unsigned int dsi_hfp_ext = 0;
	int ret;

	ret = phy_mipi_dphy_config_validate(opts);
	if (ret)
		return ret;

	ret = cdns_dsi_get_dphy_pll_cfg(dphy, cfg,
					opts, &dsi_hfp_ext);
	if (ret)
		return ret;

	opts->wakeup = cdns_dphy_get_wakeup_time_ns(dphy) / 1000;

	return 0;
}

static int cdns_dphy_tx_get_band_ctrl(unsigned long hs_clk_rate)
{
	unsigned int rate;
	int i;

	rate = hs_clk_rate / 1000000UL;

	if (rate < tx_bands[0])
		return -EOPNOTSUPP;

	for (i = 0; i < ARRAY_SIZE(tx_bands) - 1; i++) {
		if (rate >= tx_bands[i] && rate < tx_bands[i + 1])
			return i;
	}

	return -EOPNOTSUPP;
}

static int cdns_dphy_validate(struct phy *phy, enum phy_mode mode, int submode,
			      union phy_configure_opts *opts)
{
	struct cdns_dphy_cfg cfg = { 0 };

	if (mode != PHY_MODE_MIPI_DPHY)
		return -EINVAL;

	return cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
}

static int cdns_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
{
	struct cdns_dphy *dphy = phy_get_drvdata(phy);
	struct cdns_dphy_cfg cfg = { 0 };
	int ret, band_ctrl;
	unsigned int reg;

	ret = cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
	if (ret)
		return ret;

	/*
	 * Configure the internal PSM clk divider so that the DPHY has a
	 * 1MHz clk (or something close).
	 */
	ret = cdns_dphy_setup_psm(dphy);
	if (ret)
		return ret;

	/*
	 * Configure attach clk lanes to data lanes: the DPHY has 2 clk lanes
	 * and 8 data lanes, each clk lane can be attache different set of
	 * data lanes. The 2 groups are named 'left' and 'right', so here we
	 * just say that we want the 'left' clk lane to drive the 'left' data
	 * lanes.
	 */
	cdns_dphy_set_clk_lane_cfg(dphy, DPHY_CLK_CFG_LEFT_DRIVES_LEFT);

	/*
	 * Configure the DPHY PLL that will be used to generate the TX byte
	 * clk.
	 */
	cdns_dphy_set_pll_cfg(dphy, &cfg);

	band_ctrl = cdns_dphy_tx_get_band_ctrl(opts->mipi_dphy.hs_clk_rate);
	if (band_ctrl < 0)
		return band_ctrl;

	reg = FIELD_PREP(DPHY_BAND_CFG_LEFT_BAND, band_ctrl) |
	      FIELD_PREP(DPHY_BAND_CFG_RIGHT_BAND, band_ctrl);
	writel(reg, dphy->regs + DPHY_BAND_CFG);

	return 0;
}

static int cdns_dphy_power_on(struct phy *phy)
{
	struct cdns_dphy *dphy = phy_get_drvdata(phy);

	clk_prepare_enable(dphy->psm_clk);
	clk_prepare_enable(dphy->pll_ref_clk);

	/* Start TX state machine. */
	writel(DPHY_CMN_SSM_EN | DPHY_CMN_TX_MODE_EN,
	       dphy->regs + DPHY_CMN_SSM);

	return 0;
}

static int cdns_dphy_power_off(struct phy *phy)
{
	struct cdns_dphy *dphy = phy_get_drvdata(phy);

	clk_disable_unprepare(dphy->pll_ref_clk);
	clk_disable_unprepare(dphy->psm_clk);

	return 0;
}

static const struct phy_ops cdns_dphy_ops = {
	.configure	= cdns_dphy_configure,
	.validate	= cdns_dphy_validate,
	.power_on	= cdns_dphy_power_on,
	.power_off	= cdns_dphy_power_off,
};

static int cdns_dphy_probe(struct platform_device *pdev)
{
	struct phy_provider *phy_provider;
	struct cdns_dphy *dphy;
	int ret;

	dphy = devm_kzalloc(&pdev->dev, sizeof(*dphy), GFP_KERNEL);
	if (!dphy)
		return -ENOMEM;
	dev_set_drvdata(&pdev->dev, dphy);

	dphy->ops = of_device_get_match_data(&pdev->dev);
	if (!dphy->ops)
		return -EINVAL;

	dphy->regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(dphy->regs))
		return PTR_ERR(dphy->regs);

	dphy->psm_clk = devm_clk_get(&pdev->dev, "psm");
	if (IS_ERR(dphy->psm_clk))
		return PTR_ERR(dphy->psm_clk);

	dphy->pll_ref_clk = devm_clk_get(&pdev->dev, "pll_ref");
	if (IS_ERR(dphy->pll_ref_clk))
		return PTR_ERR(dphy->pll_ref_clk);

	if (dphy->ops->probe) {
		ret = dphy->ops->probe(dphy);
		if (ret)
			return ret;
	}

	dphy->phy = devm_phy_create(&pdev->dev, NULL, &cdns_dphy_ops);
	if (IS_ERR(dphy->phy)) {
		dev_err(&pdev->dev, "failed to create PHY\n");
		if (dphy->ops->remove)
			dphy->ops->remove(dphy);
		return PTR_ERR(dphy->phy);
	}

	phy_set_drvdata(dphy->phy, dphy);
	phy_provider = devm_of_phy_provider_register(&pdev->dev,
						     of_phy_simple_xlate);

	return PTR_ERR_OR_ZERO(phy_provider);
}

static int cdns_dphy_remove(struct platform_device *pdev)
{
	struct cdns_dphy *dphy = dev_get_drvdata(&pdev->dev);

	if (dphy->ops->remove)
		dphy->ops->remove(dphy);

	return 0;
}

static const struct of_device_id cdns_dphy_of_match[] = {
	{ .compatible = "cdns,dphy", .data = &ref_dphy_ops },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, cdns_dphy_of_match);

static struct platform_driver cdns_dphy_platform_driver = {
	.probe		= cdns_dphy_probe,
	.remove		= cdns_dphy_remove,
	.driver		= {
		.name		= "cdns-mipi-dphy",
		.of_match_table	= cdns_dphy_of_match,
	},
};
module_platform_driver(cdns_dphy_platform_driver);

MODULE_AUTHOR("Maxime Ripard <maxime.ripard@bootlin.com>");
MODULE_DESCRIPTION("Cadence MIPI D-PHY Driver");
MODULE_LICENSE("GPL");