Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 893 insertions, 0 deletions

diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
new file mode 100644
index 000000000..d1a2418b0
--- /dev/null
+++ b/drivers/mmc/host/sdhci-of-arasan.c
@@ -0,0 +1,893 @@
+/*
+ * Arasan Secure Digital Host Controller Interface.
+ * Copyright (C) 2011 - 2012 Michal Simek <monstr@monstr.eu>
+ * Copyright (c) 2012 Wind River Systems, Inc.
+ * Copyright (C) 2013 Pengutronix e.K.
+ * Copyright (C) 2013 Xilinx Inc.
+ *
+ * Based on sdhci-of-esdhc.c
+ *
+ * Copyright (c) 2007 Freescale Semiconductor, Inc.
+ * Copyright (c) 2009 MontaVista Software, Inc.
+ *
+ * Authors: Xiaobo Xie <X.Xie@freescale.com>
+ *	    Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/phy/phy.h>
+#include <linux/regmap.h>
+#include <linux/of.h>
+
+#include "cqhci.h"
+#include "sdhci-pltfm.h"
+
+#define SDHCI_ARASAN_VENDOR_REGISTER	0x78
+#define SDHCI_ARASAN_CQE_BASE_ADDR	0x200
+#define VENDOR_ENHANCED_STROBE		BIT(0)
+
+#define PHY_CLK_TOO_SLOW_HZ		400000
+
+/*
+ * On some SoCs the syscon area has a feature where the upper 16-bits of
+ * each 32-bit register act as a write mask for the lower 16-bits.  This allows
+ * atomic updates of the register without locking.  This macro is used on SoCs
+ * that have that feature.
+ */
+#define HIWORD_UPDATE(val, mask, shift) \
+		((val) << (shift) | (mask) << ((shift) + 16))
+
+/**
+ * struct sdhci_arasan_soc_ctl_field - Field used in sdhci_arasan_soc_ctl_map
+ *
+ * @reg:	Offset within the syscon of the register containing this field
+ * @width:	Number of bits for this field
+ * @shift:	Bit offset within @reg of this field (or -1 if not avail)
+ */
+struct sdhci_arasan_soc_ctl_field {
+	u32 reg;
+	u16 width;
+	s16 shift;
+};
+
+/**
+ * struct sdhci_arasan_soc_ctl_map - Map in syscon to corecfg registers
+ *
+ * It's up to the licensee of the Arsan IP block to make these available
+ * somewhere if needed.  Presumably these will be scattered somewhere that's
+ * accessible via the syscon API.
+ *
+ * @baseclkfreq:	Where to find corecfg_baseclkfreq
+ * @clockmultiplier:	Where to find corecfg_clockmultiplier
+ * @hiword_update:	If true, use HIWORD_UPDATE to access the syscon
+ */
+struct sdhci_arasan_soc_ctl_map {
+	struct sdhci_arasan_soc_ctl_field	baseclkfreq;
+	struct sdhci_arasan_soc_ctl_field	clockmultiplier;
+	bool					hiword_update;
+};
+
+/**
+ * struct sdhci_arasan_data
+ * @host:		Pointer to the main SDHCI host structure.
+ * @clk_ahb:		Pointer to the AHB clock
+ * @phy:		Pointer to the generic phy
+ * @is_phy_on:		True if the PHY is on; false if not.
+ * @sdcardclk_hw:	Struct for the clock we might provide to a PHY.
+ * @sdcardclk:		Pointer to normal 'struct clock' for sdcardclk_hw.
+ * @soc_ctl_base:	Pointer to regmap for syscon for soc_ctl registers.
+ * @soc_ctl_map:	Map to get offsets into soc_ctl registers.
+ */
+struct sdhci_arasan_data {
+	struct sdhci_host *host;
+	struct clk	*clk_ahb;
+	struct phy	*phy;
+	bool		is_phy_on;
+
+	bool		has_cqe;
+	struct clk_hw	sdcardclk_hw;
+	struct clk      *sdcardclk;
+
+	struct regmap	*soc_ctl_base;
+	const struct sdhci_arasan_soc_ctl_map *soc_ctl_map;
+	unsigned int	quirks; /* Arasan deviations from spec */
+
+/* Controller does not have CD wired and will not function normally without */
+#define SDHCI_ARASAN_QUIRK_FORCE_CDTEST	BIT(0)
+/* Controller immediately reports SDHCI_CLOCK_INT_STABLE after enabling the
+ * internal clock even when the clock isn't stable */
+#define SDHCI_ARASAN_QUIRK_CLOCK_UNSTABLE BIT(1)
+};
+
+static const struct sdhci_arasan_soc_ctl_map rk3399_soc_ctl_map = {
+	.baseclkfreq = { .reg = 0xf000, .width = 8, .shift = 8 },
+	.clockmultiplier = { .reg = 0xf02c, .width = 8, .shift = 0},
+	.hiword_update = true,
+};
+
+/**
+ * sdhci_arasan_syscon_write - Write to a field in soc_ctl registers
+ *
+ * This function allows writing to fields in sdhci_arasan_soc_ctl_map.
+ * Note that if a field is specified as not available (shift < 0) then
+ * this function will silently return an error code.  It will be noisy
+ * and print errors for any other (unexpected) errors.
+ *
+ * @host:	The sdhci_host
+ * @fld:	The field to write to
+ * @val:	The value to write
+ */
+static int sdhci_arasan_syscon_write(struct sdhci_host *host,
+				   const struct sdhci_arasan_soc_ctl_field *fld,
+				   u32 val)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	struct regmap *soc_ctl_base = sdhci_arasan->soc_ctl_base;
+	u32 reg = fld->reg;
+	u16 width = fld->width;
+	s16 shift = fld->shift;
+	int ret;
+
+	/*
+	 * Silently return errors for shift < 0 so caller doesn't have
+	 * to check for fields which are optional.  For fields that
+	 * are required then caller needs to do something special
+	 * anyway.
+	 */
+	if (shift < 0)
+		return -EINVAL;
+
+	if (sdhci_arasan->soc_ctl_map->hiword_update)
+		ret = regmap_write(soc_ctl_base, reg,
+				   HIWORD_UPDATE(val, GENMASK(width, 0),
+						 shift));
+	else
+		ret = regmap_update_bits(soc_ctl_base, reg,
+					 GENMASK(shift + width, shift),
+					 val << shift);
+
+	/* Yell about (unexpected) regmap errors */
+	if (ret)
+		pr_warn("%s: Regmap write fail: %d\n",
+			 mmc_hostname(host->mmc), ret);
+
+	return ret;
+}
+
+static void sdhci_arasan_set_clock(struct sdhci_host *host, unsigned int clock)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	bool ctrl_phy = false;
+
+	if (!IS_ERR(sdhci_arasan->phy)) {
+		if (!sdhci_arasan->is_phy_on && clock <= PHY_CLK_TOO_SLOW_HZ) {
+			/*
+			 * If PHY off, set clock to max speed and power PHY on.
+			 *
+			 * Although PHY docs apparently suggest power cycling
+			 * when changing the clock the PHY doesn't like to be
+			 * powered on while at low speeds like those used in ID
+			 * mode.  Even worse is powering the PHY on while the
+			 * clock is off.
+			 *
+			 * To workaround the PHY limitations, the best we can
+			 * do is to power it on at a faster speed and then slam
+			 * through low speeds without power cycling.
+			 */
+			sdhci_set_clock(host, host->max_clk);
+			if (phy_power_on(sdhci_arasan->phy)) {
+				pr_err("%s: Cannot power on phy.\n",
+				       mmc_hostname(host->mmc));
+				return;
+			}
+
+			sdhci_arasan->is_phy_on = true;
+
+			/*
+			 * We'll now fall through to the below case with
+			 * ctrl_phy = false (so we won't turn off/on).  The
+			 * sdhci_set_clock() will set the real clock.
+			 */
+		} else if (clock > PHY_CLK_TOO_SLOW_HZ) {
+			/*
+			 * At higher clock speeds the PHY is fine being power
+			 * cycled and docs say you _should_ power cycle when
+			 * changing clock speeds.
+			 */
+			ctrl_phy = true;
+		}
+	}
+
+	if (ctrl_phy && sdhci_arasan->is_phy_on) {
+		phy_power_off(sdhci_arasan->phy);
+		sdhci_arasan->is_phy_on = false;
+	}
+
+	sdhci_set_clock(host, clock);
+
+	if (sdhci_arasan->quirks & SDHCI_ARASAN_QUIRK_CLOCK_UNSTABLE)
+		/*
+		 * Some controllers immediately report SDHCI_CLOCK_INT_STABLE
+		 * after enabling the clock even though the clock is not
+		 * stable. Trying to use a clock without waiting here results
+		 * in EILSEQ while detecting some older/slower cards. The
+		 * chosen delay is the maximum delay from sdhci_set_clock.
+		 */
+		msleep(20);
+
+	if (ctrl_phy) {
+		if (phy_power_on(sdhci_arasan->phy)) {
+			pr_err("%s: Cannot power on phy.\n",
+			       mmc_hostname(host->mmc));
+			return;
+		}
+
+		sdhci_arasan->is_phy_on = true;
+	}
+}
+
+static void sdhci_arasan_hs400_enhanced_strobe(struct mmc_host *mmc,
+					struct mmc_ios *ios)
+{
+	u32 vendor;
+	struct sdhci_host *host = mmc_priv(mmc);
+
+	vendor = sdhci_readl(host, SDHCI_ARASAN_VENDOR_REGISTER);
+	if (ios->enhanced_strobe)
+		vendor |= VENDOR_ENHANCED_STROBE;
+	else
+		vendor &= ~VENDOR_ENHANCED_STROBE;
+
+	sdhci_writel(host, vendor, SDHCI_ARASAN_VENDOR_REGISTER);
+}
+
+static void sdhci_arasan_reset(struct sdhci_host *host, u8 mask)
+{
+	u8 ctrl;
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+
+	sdhci_reset(host, mask);
+
+	if (sdhci_arasan->quirks & SDHCI_ARASAN_QUIRK_FORCE_CDTEST) {
+		ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
+		ctrl |= SDHCI_CTRL_CDTEST_INS | SDHCI_CTRL_CDTEST_EN;
+		sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
+	}
+}
+
+static int sdhci_arasan_voltage_switch(struct mmc_host *mmc,
+				       struct mmc_ios *ios)
+{
+	switch (ios->signal_voltage) {
+	case MMC_SIGNAL_VOLTAGE_180:
+		/*
+		 * Plese don't switch to 1V8 as arasan,5.1 doesn't
+		 * actually refer to this setting to indicate the
+		 * signal voltage and the state machine will be broken
+		 * actually if we force to enable 1V8. That's something
+		 * like broken quirk but we could work around here.
+		 */
+		return 0;
+	case MMC_SIGNAL_VOLTAGE_330:
+	case MMC_SIGNAL_VOLTAGE_120:
+		/* We don't support 3V3 and 1V2 */
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static void sdhci_arasan_set_power(struct sdhci_host *host, unsigned char mode,
+		     unsigned short vdd)
+{
+	if (!IS_ERR(host->mmc->supply.vmmc)) {
+		struct mmc_host *mmc = host->mmc;
+
+		mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
+	}
+	sdhci_set_power_noreg(host, mode, vdd);
+}
+
+static const struct sdhci_ops sdhci_arasan_ops = {
+	.set_clock = sdhci_arasan_set_clock,
+	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
+	.get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
+	.set_bus_width = sdhci_set_bus_width,
+	.reset = sdhci_arasan_reset,
+	.set_uhs_signaling = sdhci_set_uhs_signaling,
+	.set_power = sdhci_arasan_set_power,
+};
+
+static const struct sdhci_pltfm_data sdhci_arasan_pdata = {
+	.ops = &sdhci_arasan_ops,
+	.quirks = SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
+	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
+			SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN |
+			SDHCI_QUIRK2_STOP_WITH_TC,
+};
+
+static u32 sdhci_arasan_cqhci_irq(struct sdhci_host *host, u32 intmask)
+{
+	int cmd_error = 0;
+	int data_error = 0;
+
+	if (!sdhci_cqe_irq(host, intmask, &cmd_error, &data_error))
+		return intmask;
+
+	cqhci_irq(host->mmc, intmask, cmd_error, data_error);
+
+	return 0;
+}
+
+static void sdhci_arasan_dumpregs(struct mmc_host *mmc)
+{
+	sdhci_dumpregs(mmc_priv(mmc));
+}
+
+static void sdhci_arasan_cqe_enable(struct mmc_host *mmc)
+{
+	struct sdhci_host *host = mmc_priv(mmc);
+	u32 reg;
+
+	reg = sdhci_readl(host, SDHCI_PRESENT_STATE);
+	while (reg & SDHCI_DATA_AVAILABLE) {
+		sdhci_readl(host, SDHCI_BUFFER);
+		reg = sdhci_readl(host, SDHCI_PRESENT_STATE);
+	}
+
+	sdhci_cqe_enable(mmc);
+}
+
+static const struct cqhci_host_ops sdhci_arasan_cqhci_ops = {
+	.enable         = sdhci_arasan_cqe_enable,
+	.disable        = sdhci_cqe_disable,
+	.dumpregs       = sdhci_arasan_dumpregs,
+};
+
+static const struct sdhci_ops sdhci_arasan_cqe_ops = {
+	.set_clock = sdhci_arasan_set_clock,
+	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
+	.get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
+	.set_bus_width = sdhci_set_bus_width,
+	.reset = sdhci_arasan_reset,
+	.set_uhs_signaling = sdhci_set_uhs_signaling,
+	.set_power = sdhci_arasan_set_power,
+	.irq = sdhci_arasan_cqhci_irq,
+};
+
+static const struct sdhci_pltfm_data sdhci_arasan_cqe_pdata = {
+	.ops = &sdhci_arasan_cqe_ops,
+	.quirks = SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
+	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
+			SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
+};
+
+#ifdef CONFIG_PM_SLEEP
+/**
+ * sdhci_arasan_suspend - Suspend method for the driver
+ * @dev:	Address of the device structure
+ * Returns 0 on success and error value on error
+ *
+ * Put the device in a low power state.
+ */
+static int sdhci_arasan_suspend(struct device *dev)
+{
+	struct sdhci_host *host = dev_get_drvdata(dev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	int ret;
+
+	if (host->tuning_mode != SDHCI_TUNING_MODE_3)
+		mmc_retune_needed(host->mmc);
+
+	if (sdhci_arasan->has_cqe) {
+		ret = cqhci_suspend(host->mmc);
+		if (ret)
+			return ret;
+	}
+
+	ret = sdhci_suspend_host(host);
+	if (ret)
+		return ret;
+
+	if (!IS_ERR(sdhci_arasan->phy) && sdhci_arasan->is_phy_on) {
+		ret = phy_power_off(sdhci_arasan->phy);
+		if (ret) {
+			dev_err(dev, "Cannot power off phy.\n");
+			if (sdhci_resume_host(host))
+				dev_err(dev, "Cannot resume host.\n");
+
+			return ret;
+		}
+		sdhci_arasan->is_phy_on = false;
+	}
+
+	clk_disable(pltfm_host->clk);
+	clk_disable(sdhci_arasan->clk_ahb);
+
+	return 0;
+}
+
+/**
+ * sdhci_arasan_resume - Resume method for the driver
+ * @dev:	Address of the device structure
+ * Returns 0 on success and error value on error
+ *
+ * Resume operation after suspend
+ */
+static int sdhci_arasan_resume(struct device *dev)
+{
+	struct sdhci_host *host = dev_get_drvdata(dev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	int ret;
+
+	ret = clk_enable(sdhci_arasan->clk_ahb);
+	if (ret) {
+		dev_err(dev, "Cannot enable AHB clock.\n");
+		return ret;
+	}
+
+	ret = clk_enable(pltfm_host->clk);
+	if (ret) {
+		dev_err(dev, "Cannot enable SD clock.\n");
+		return ret;
+	}
+
+	if (!IS_ERR(sdhci_arasan->phy) && host->mmc->actual_clock) {
+		ret = phy_power_on(sdhci_arasan->phy);
+		if (ret) {
+			dev_err(dev, "Cannot power on phy.\n");
+			return ret;
+		}
+		sdhci_arasan->is_phy_on = true;
+	}
+
+	ret = sdhci_resume_host(host);
+	if (ret) {
+		dev_err(dev, "Cannot resume host.\n");
+		return ret;
+	}
+
+	if (sdhci_arasan->has_cqe)
+		return cqhci_resume(host->mmc);
+
+	return 0;
+}
+#endif /* ! CONFIG_PM_SLEEP */
+
+static SIMPLE_DEV_PM_OPS(sdhci_arasan_dev_pm_ops, sdhci_arasan_suspend,
+			 sdhci_arasan_resume);
+
+static const struct of_device_id sdhci_arasan_of_match[] = {
+	/* SoC-specific compatible strings w/ soc_ctl_map */
+	{
+		.compatible = "rockchip,rk3399-sdhci-5.1",
+		.data = &rk3399_soc_ctl_map,
+	},
+
+	/* Generic compatible below here */
+	{ .compatible = "arasan,sdhci-8.9a" },
+	{ .compatible = "arasan,sdhci-5.1" },
+	{ .compatible = "arasan,sdhci-4.9a" },
+
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sdhci_arasan_of_match);
+
+/**
+ * sdhci_arasan_sdcardclk_recalc_rate - Return the card clock rate
+ *
+ * Return the current actual rate of the SD card clock.  This can be used
+ * to communicate with out PHY.
+ *
+ * @hw:			Pointer to the hardware clock structure.
+ * @parent_rate		The parent rate (should be rate of clk_xin).
+ * Returns the card clock rate.
+ */
+static unsigned long sdhci_arasan_sdcardclk_recalc_rate(struct clk_hw *hw,
+						      unsigned long parent_rate)
+
+{
+	struct sdhci_arasan_data *sdhci_arasan =
+		container_of(hw, struct sdhci_arasan_data, sdcardclk_hw);
+	struct sdhci_host *host = sdhci_arasan->host;
+
+	return host->mmc->actual_clock;
+}
+
+static const struct clk_ops arasan_sdcardclk_ops = {
+	.recalc_rate = sdhci_arasan_sdcardclk_recalc_rate,
+};
+
+/**
+ * sdhci_arasan_update_clockmultiplier - Set corecfg_clockmultiplier
+ *
+ * The corecfg_clockmultiplier is supposed to contain clock multiplier
+ * value of programmable clock generator.
+ *
+ * NOTES:
+ * - Many existing devices don't seem to do this and work fine.  To keep
+ *   compatibility for old hardware where the device tree doesn't provide a
+ *   register map, this function is a noop if a soc_ctl_map hasn't been provided
+ *   for this platform.
+ * - The value of corecfg_clockmultiplier should sync with that of corresponding
+ *   value reading from sdhci_capability_register. So this function is called
+ *   once at probe time and never called again.
+ *
+ * @host:		The sdhci_host
+ */
+static void sdhci_arasan_update_clockmultiplier(struct sdhci_host *host,
+						u32 value)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	const struct sdhci_arasan_soc_ctl_map *soc_ctl_map =
+		sdhci_arasan->soc_ctl_map;
+
+	/* Having a map is optional */
+	if (!soc_ctl_map)
+		return;
+
+	/* If we have a map, we expect to have a syscon */
+	if (!sdhci_arasan->soc_ctl_base) {
+		pr_warn("%s: Have regmap, but no soc-ctl-syscon\n",
+			mmc_hostname(host->mmc));
+		return;
+	}
+
+	sdhci_arasan_syscon_write(host, &soc_ctl_map->clockmultiplier, value);
+}
+
+/**
+ * sdhci_arasan_update_baseclkfreq - Set corecfg_baseclkfreq
+ *
+ * The corecfg_baseclkfreq is supposed to contain the MHz of clk_xin.  This
+ * function can be used to make that happen.
+ *
+ * NOTES:
+ * - Many existing devices don't seem to do this and work fine.  To keep
+ *   compatibility for old hardware where the device tree doesn't provide a
+ *   register map, this function is a noop if a soc_ctl_map hasn't been provided
+ *   for this platform.
+ * - It's assumed that clk_xin is not dynamic and that we use the SDHCI divider
+ *   to achieve lower clock rates.  That means that this function is called once
+ *   at probe time and never called again.
+ *
+ * @host:		The sdhci_host
+ */
+static void sdhci_arasan_update_baseclkfreq(struct sdhci_host *host)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	const struct sdhci_arasan_soc_ctl_map *soc_ctl_map =
+		sdhci_arasan->soc_ctl_map;
+	u32 mhz = DIV_ROUND_CLOSEST(clk_get_rate(pltfm_host->clk), 1000000);
+
+	/* Having a map is optional */
+	if (!soc_ctl_map)
+		return;
+
+	/* If we have a map, we expect to have a syscon */
+	if (!sdhci_arasan->soc_ctl_base) {
+		pr_warn("%s: Have regmap, but no soc-ctl-syscon\n",
+			mmc_hostname(host->mmc));
+		return;
+	}
+
+	sdhci_arasan_syscon_write(host, &soc_ctl_map->baseclkfreq, mhz);
+}
+
+/**
+ * sdhci_arasan_register_sdclk - Register the sdclk for a PHY to use
+ *
+ * Some PHY devices need to know what the actual card clock is.  In order for
+ * them to find out, we'll provide a clock through the common clock framework
+ * for them to query.
+ *
+ * Note: without seriously re-architecting SDHCI's clock code and testing on
+ * all platforms, there's no way to create a totally beautiful clock here
+ * with all clock ops implemented.  Instead, we'll just create a clock that can
+ * be queried and set the CLK_GET_RATE_NOCACHE attribute to tell common clock
+ * framework that we're doing things behind its back.  This should be sufficient
+ * to create nice clean device tree bindings and later (if needed) we can try
+ * re-architecting SDHCI if we see some benefit to it.
+ *
+ * @sdhci_arasan:	Our private data structure.
+ * @clk_xin:		Pointer to the functional clock
+ * @dev:		Pointer to our struct device.
+ * Returns 0 on success and error value on error
+ */
+static int sdhci_arasan_register_sdclk(struct sdhci_arasan_data *sdhci_arasan,
+				       struct clk *clk_xin,
+				       struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct clk_init_data sdcardclk_init;
+	const char *parent_clk_name;
+	int ret;
+
+	/* Providing a clock to the PHY is optional; no error if missing */
+	if (!of_find_property(np, "#clock-cells", NULL))
+		return 0;
+
+	ret = of_property_read_string_index(np, "clock-output-names", 0,
+					    &sdcardclk_init.name);
+	if (ret) {
+		dev_err(dev, "DT has #clock-cells but no clock-output-names\n");
+		return ret;
+	}
+
+	parent_clk_name = __clk_get_name(clk_xin);
+	sdcardclk_init.parent_names = &parent_clk_name;
+	sdcardclk_init.num_parents = 1;
+	sdcardclk_init.flags = CLK_GET_RATE_NOCACHE;
+	sdcardclk_init.ops = &arasan_sdcardclk_ops;
+
+	sdhci_arasan->sdcardclk_hw.init = &sdcardclk_init;
+	sdhci_arasan->sdcardclk =
+		devm_clk_register(dev, &sdhci_arasan->sdcardclk_hw);
+	sdhci_arasan->sdcardclk_hw.init = NULL;
+
+	ret = of_clk_add_provider(np, of_clk_src_simple_get,
+				  sdhci_arasan->sdcardclk);
+	if (ret)
+		dev_err(dev, "Failed to add clock provider\n");
+
+	return ret;
+}
+
+/**
+ * sdhci_arasan_unregister_sdclk - Undoes sdhci_arasan_register_sdclk()
+ *
+ * Should be called any time we're exiting and sdhci_arasan_register_sdclk()
+ * returned success.
+ *
+ * @dev:		Pointer to our struct device.
+ */
+static void sdhci_arasan_unregister_sdclk(struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+
+	if (!of_find_property(np, "#clock-cells", NULL))
+		return;
+
+	of_clk_del_provider(dev->of_node);
+}
+
+static int sdhci_arasan_add_host(struct sdhci_arasan_data *sdhci_arasan)
+{
+	struct sdhci_host *host = sdhci_arasan->host;
+	struct cqhci_host *cq_host;
+	bool dma64;
+	int ret;
+
+	if (!sdhci_arasan->has_cqe)
+		return sdhci_add_host(host);
+
+	ret = sdhci_setup_host(host);
+	if (ret)
+		return ret;
+
+	cq_host = devm_kzalloc(host->mmc->parent,
+			       sizeof(*cq_host), GFP_KERNEL);
+	if (!cq_host) {
+		ret = -ENOMEM;
+		goto cleanup;
+	}
+
+	cq_host->mmio = host->ioaddr + SDHCI_ARASAN_CQE_BASE_ADDR;
+	cq_host->ops = &sdhci_arasan_cqhci_ops;
+
+	dma64 = host->flags & SDHCI_USE_64_BIT_DMA;
+	if (dma64)
+		cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
+
+	ret = cqhci_init(cq_host, host->mmc, dma64);
+	if (ret)
+		goto cleanup;
+
+	ret = __sdhci_add_host(host);
+	if (ret)
+		goto cleanup;
+
+	return 0;
+
+cleanup:
+	sdhci_cleanup_host(host);
+	return ret;
+}
+
+static int sdhci_arasan_probe(struct platform_device *pdev)
+{
+	int ret;
+	const struct of_device_id *match;
+	struct device_node *node;
+	struct clk *clk_xin;
+	struct sdhci_host *host;
+	struct sdhci_pltfm_host *pltfm_host;
+	struct sdhci_arasan_data *sdhci_arasan;
+	struct device_node *np = pdev->dev.of_node;
+	const struct sdhci_pltfm_data *pdata;
+
+	if (of_device_is_compatible(pdev->dev.of_node, "arasan,sdhci-5.1"))
+		pdata = &sdhci_arasan_cqe_pdata;
+	else
+		pdata = &sdhci_arasan_pdata;
+
+	host = sdhci_pltfm_init(pdev, pdata, sizeof(*sdhci_arasan));
+
+	if (IS_ERR(host))
+		return PTR_ERR(host);
+
+	pltfm_host = sdhci_priv(host);
+	sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	sdhci_arasan->host = host;
+
+	match = of_match_node(sdhci_arasan_of_match, pdev->dev.of_node);
+	sdhci_arasan->soc_ctl_map = match->data;
+
+	node = of_parse_phandle(pdev->dev.of_node, "arasan,soc-ctl-syscon", 0);
+	if (node) {
+		sdhci_arasan->soc_ctl_base = syscon_node_to_regmap(node);
+		of_node_put(node);
+
+		if (IS_ERR(sdhci_arasan->soc_ctl_base)) {
+			ret = PTR_ERR(sdhci_arasan->soc_ctl_base);
+			if (ret != -EPROBE_DEFER)
+				dev_err(&pdev->dev, "Can't get syscon: %d\n",
+					ret);
+			goto err_pltfm_free;
+		}
+	}
+
+	sdhci_arasan->clk_ahb = devm_clk_get(&pdev->dev, "clk_ahb");
+	if (IS_ERR(sdhci_arasan->clk_ahb)) {
+		dev_err(&pdev->dev, "clk_ahb clock not found.\n");
+		ret = PTR_ERR(sdhci_arasan->clk_ahb);
+		goto err_pltfm_free;
+	}
+
+	clk_xin = devm_clk_get(&pdev->dev, "clk_xin");
+	if (IS_ERR(clk_xin)) {
+		dev_err(&pdev->dev, "clk_xin clock not found.\n");
+		ret = PTR_ERR(clk_xin);
+		goto err_pltfm_free;
+	}
+
+	ret = clk_prepare_enable(sdhci_arasan->clk_ahb);
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to enable AHB clock.\n");
+		goto err_pltfm_free;
+	}
+
+	ret = clk_prepare_enable(clk_xin);
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to enable SD clock.\n");
+		goto clk_dis_ahb;
+	}
+
+	sdhci_get_of_property(pdev);
+
+	if (of_property_read_bool(np, "xlnx,fails-without-test-cd"))
+		sdhci_arasan->quirks |= SDHCI_ARASAN_QUIRK_FORCE_CDTEST;
+
+	if (of_property_read_bool(np, "xlnx,int-clock-stable-broken"))
+		sdhci_arasan->quirks |= SDHCI_ARASAN_QUIRK_CLOCK_UNSTABLE;
+
+	pltfm_host->clk = clk_xin;
+
+	if (of_device_is_compatible(pdev->dev.of_node,
+				    "rockchip,rk3399-sdhci-5.1"))
+		sdhci_arasan_update_clockmultiplier(host, 0x0);
+
+	sdhci_arasan_update_baseclkfreq(host);
+
+	ret = sdhci_arasan_register_sdclk(sdhci_arasan, clk_xin, &pdev->dev);
+	if (ret)
+		goto clk_disable_all;
+
+	ret = mmc_of_parse(host->mmc);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "parsing dt failed (%d)\n", ret);
+		goto unreg_clk;
+	}
+
+	sdhci_arasan->phy = ERR_PTR(-ENODEV);
+	if (of_device_is_compatible(pdev->dev.of_node,
+				    "arasan,sdhci-5.1")) {
+		sdhci_arasan->phy = devm_phy_get(&pdev->dev,
+						 "phy_arasan");
+		if (IS_ERR(sdhci_arasan->phy)) {
+			ret = PTR_ERR(sdhci_arasan->phy);
+			dev_err(&pdev->dev, "No phy for arasan,sdhci-5.1.\n");
+			goto unreg_clk;
+		}
+
+		ret = phy_init(sdhci_arasan->phy);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "phy_init err.\n");
+			goto unreg_clk;
+		}
+
+		host->mmc_host_ops.hs400_enhanced_strobe =
+					sdhci_arasan_hs400_enhanced_strobe;
+		host->mmc_host_ops.start_signal_voltage_switch =
+					sdhci_arasan_voltage_switch;
+		sdhci_arasan->has_cqe = true;
+		host->mmc->caps2 |= MMC_CAP2_CQE;
+
+		if (!of_property_read_bool(np, "disable-cqe-dcmd"))
+			host->mmc->caps2 |= MMC_CAP2_CQE_DCMD;
+	}
+
+	ret = sdhci_arasan_add_host(sdhci_arasan);
+	if (ret)
+		goto err_add_host;
+
+	return 0;
+
+err_add_host:
+	if (!IS_ERR(sdhci_arasan->phy))
+		phy_exit(sdhci_arasan->phy);
+unreg_clk:
+	sdhci_arasan_unregister_sdclk(&pdev->dev);
+clk_disable_all:
+	clk_disable_unprepare(clk_xin);
+clk_dis_ahb:
+	clk_disable_unprepare(sdhci_arasan->clk_ahb);
+err_pltfm_free:
+	sdhci_pltfm_free(pdev);
+	return ret;
+}
+
+static int sdhci_arasan_remove(struct platform_device *pdev)
+{
+	int ret;
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	struct clk *clk_ahb = sdhci_arasan->clk_ahb;
+
+	if (!IS_ERR(sdhci_arasan->phy)) {
+		if (sdhci_arasan->is_phy_on)
+			phy_power_off(sdhci_arasan->phy);
+		phy_exit(sdhci_arasan->phy);
+	}
+
+	sdhci_arasan_unregister_sdclk(&pdev->dev);
+
+	ret = sdhci_pltfm_unregister(pdev);
+
+	clk_disable_unprepare(clk_ahb);
+
+	return ret;
+}
+
+static struct platform_driver sdhci_arasan_driver = {
+	.driver = {
+		.name = "sdhci-arasan",
+		.of_match_table = sdhci_arasan_of_match,
+		.pm = &sdhci_arasan_dev_pm_ops,
+	},
+	.probe = sdhci_arasan_probe,
+	.remove = sdhci_arasan_remove,
+};
+
+module_platform_driver(sdhci_arasan_driver);
+
+MODULE_DESCRIPTION("Driver for the Arasan SDHCI Controller");
+MODULE_AUTHOR("Soeren Brinkmann <soren.brinkmann@xilinx.com>");
+MODULE_LICENSE("GPL");