drivers/mmc/host/dw_mmc-rockchip.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
  */

 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/clk.h>
 #include <linux/mmc/host.h>
 #include <linux/of_address.h>
 #include <linux/mmc/slot-gpio.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>

 #include "dw_mmc.h"
 #include "dw_mmc-pltfm.h"

 #define RK3288_CLKGEN_DIV	2

 static const unsigned int freqs[] = { 100000, 200000, 300000, 400000 };

 struct dw_mci_rockchip_priv_data {
 	struct clk		*drv_clk;
 	struct clk		*sample_clk;
 	int			default_sample_phase;
 	int			num_phases;
 };

 static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
 {
 	struct dw_mci_rockchip_priv_data *priv = host->priv;
 	int ret;
 	unsigned int cclkin;
 	u32 bus_hz;

 	if (ios->clock == 0)
 		return;

 	/*
 	 * cclkin: source clock of mmc controller
 	 * bus_hz: card interface clock generated by CLKGEN
 	 * bus_hz = cclkin / RK3288_CLKGEN_DIV
 	 * ios->clock = (div == 0) ? bus_hz : (bus_hz / (2 * div))
 	 *
 	 * Note: div can only be 0 or 1, but div must be set to 1 for eMMC
 	 * DDR52 8-bit mode.
 	 */
 	if (ios->bus_width == MMC_BUS_WIDTH_8 &&
 	    ios->timing == MMC_TIMING_MMC_DDR52)
 		cclkin = 2 * ios->clock * RK3288_CLKGEN_DIV;
 	else
 		cclkin = ios->clock * RK3288_CLKGEN_DIV;

 	ret = clk_set_rate(host->ciu_clk, cclkin);
 	if (ret)
 		dev_warn(host->dev, "failed to set rate %uHz err: %d\n", cclkin, ret);

 	bus_hz = clk_get_rate(host->ciu_clk) / RK3288_CLKGEN_DIV;
 	if (bus_hz != host->bus_hz) {
 		host->bus_hz = bus_hz;
 		/* force dw_mci_setup_bus() */
 		host->current_speed = 0;
 	}

 	/* Make sure we use phases which we can enumerate with */
 	if (!IS_ERR(priv->sample_clk) && ios->timing <= MMC_TIMING_SD_HS)
 		clk_set_phase(priv->sample_clk, priv->default_sample_phase);

 	/*
 	 * Set the drive phase offset based on speed mode to achieve hold times.
 	 *
 	 * NOTE: this is _not_ a value that is dynamically tuned and is also
 	 * _not_ a value that will vary from board to board.  It is a value
 	 * that could vary between different SoC models if they had massively
 	 * different output clock delays inside their dw_mmc IP block (delay_o),
 	 * but since it's OK to overshoot a little we don't need to do complex
 	 * calculations and can pick values that will just work for everyone.
 	 *
 	 * When picking values we'll stick with picking 0/90/180/270 since
 	 * those can be made very accurately on all known Rockchip SoCs.
 	 *
 	 * Note that these values match values from the DesignWare Databook
 	 * tables for the most part except for SDR12 and "ID mode".  For those
 	 * two modes the databook calculations assume a clock in of 50MHz.  As
 	 * seen above, we always use a clock in rate that is exactly the
 	 * card's input clock (times RK3288_CLKGEN_DIV, but that gets divided
 	 * back out before the controller sees it).
 	 *
 	 * From measurement of a single device, it appears that delay_o is
 	 * about .5 ns.  Since we try to leave a bit of margin, it's expected
 	 * that numbers here will be fine even with much larger delay_o
 	 * (the 1.4 ns assumed by the DesignWare Databook would result in the
 	 * same results, for instance).
 	 */
 	if (!IS_ERR(priv->drv_clk)) {
 		int phase;

 		/*
 		 * In almost all cases a 90 degree phase offset will provide
 		 * sufficient hold times across all valid input clock rates
 		 * assuming delay_o is not absurd for a given SoC.  We'll use
 		 * that as a default.
 		 */
 		phase = 90;

 		switch (ios->timing) {
 		case MMC_TIMING_MMC_DDR52:
 			/*
 			 * Since clock in rate with MMC_DDR52 is doubled when
 			 * bus width is 8 we need to double the phase offset
 			 * to get the same timings.
 			 */
 			if (ios->bus_width == MMC_BUS_WIDTH_8)
 				phase = 180;
 			break;
 		case MMC_TIMING_UHS_SDR104:
 		case MMC_TIMING_MMC_HS200:
 			/*
 			 * In the case of 150 MHz clock (typical max for
 			 * Rockchip SoCs), 90 degree offset will add a delay
 			 * of 1.67 ns.  That will meet min hold time of .8 ns
 			 * as long as clock output delay is < .87 ns.  On
 			 * SoCs measured this seems to be OK, but it doesn't
 			 * hurt to give margin here, so we use 180.
 			 */
 			phase = 180;
 			break;
 		}

 		clk_set_phase(priv->drv_clk, phase);
 	}
 }

 #define TUNING_ITERATION_TO_PHASE(i, num_phases) \
 		(DIV_ROUND_UP((i) * 360, num_phases))

 static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
 {
 	struct dw_mci *host = slot->host;
 	struct dw_mci_rockchip_priv_data *priv = host->priv;
 	struct mmc_host *mmc = slot->mmc;
 	int ret = 0;
 	int i;
 	bool v, prev_v = 0, first_v;
 	struct range_t {
 		int start;
 		int end; /* inclusive */
 	};
 	struct range_t *ranges;
 	unsigned int range_count = 0;
 	int longest_range_len = -1;
 	int longest_range = -1;
 	int middle_phase;

 	if (IS_ERR(priv->sample_clk)) {
 		dev_err(host->dev, "Tuning clock (sample_clk) not defined.\n");
 		return -EIO;
 	}

 	ranges = kmalloc_array(priv->num_phases / 2 + 1,
 			       sizeof(*ranges), GFP_KERNEL);
 	if (!ranges)
 		return -ENOMEM;

 	/* Try each phase and extract good ranges */
 	for (i = 0; i < priv->num_phases; ) {
 		clk_set_phase(priv->sample_clk,
 			      TUNING_ITERATION_TO_PHASE(i, priv->num_phases));

 		v = !mmc_send_tuning(mmc, opcode, NULL);

 		if (i == 0)
 			first_v = v;

 		if ((!prev_v) && v) {
 			range_count++;
 			ranges[range_count-1].start = i;
 		}
 		if (v) {
 			ranges[range_count-1].end = i;
 			i++;
 		} else if (i == priv->num_phases - 1) {
 			/* No extra skipping rules if we're at the end */
 			i++;
 		} else {
 			/*
 			 * No need to check too close to an invalid
 			 * one since testing bad phases is slow.  Skip
 			 * 20 degrees.
 			 */
 			i += DIV_ROUND_UP(20 * priv->num_phases, 360);

 			/* Always test the last one */
 			if (i >= priv->num_phases)
 				i = priv->num_phases - 1;
 		}

 		prev_v = v;
 	}

 	if (range_count == 0) {
 		dev_warn(host->dev, "All phases bad!");
 		ret = -EIO;
 		goto free;
 	}

 	/* wrap around case, merge the end points */
 	if ((range_count > 1) && first_v && v) {
 		ranges[0].start = ranges[range_count-1].start;
 		range_count--;
 	}

 	if (ranges[0].start == 0 && ranges[0].end == priv->num_phases - 1) {
 		clk_set_phase(priv->sample_clk, priv->default_sample_phase);
 		dev_info(host->dev, "All phases work, using default phase %d.",
 			 priv->default_sample_phase);
 		goto free;
 	}

 	/* Find the longest range */
 	for (i = 0; i < range_count; i++) {
 		int len = (ranges[i].end - ranges[i].start + 1);

 		if (len < 0)
 			len += priv->num_phases;

 		if (longest_range_len < len) {
 			longest_range_len = len;
 			longest_range = i;
 		}

 		dev_dbg(host->dev, "Good phase range %d-%d (%d len)\n",
 			TUNING_ITERATION_TO_PHASE(ranges[i].start,
 						  priv->num_phases),
 			TUNING_ITERATION_TO_PHASE(ranges[i].end,
 						  priv->num_phases),
 			len
 		);
 	}

 	dev_dbg(host->dev, "Best phase range %d-%d (%d len)\n",
 		TUNING_ITERATION_TO_PHASE(ranges[longest_range].start,
 					  priv->num_phases),
 		TUNING_ITERATION_TO_PHASE(ranges[longest_range].end,
 					  priv->num_phases),
 		longest_range_len
 	);

 	middle_phase = ranges[longest_range].start + longest_range_len / 2;
 	middle_phase %= priv->num_phases;
 	dev_info(host->dev, "Successfully tuned phase to %d\n",
 		 TUNING_ITERATION_TO_PHASE(middle_phase, priv->num_phases));

 	clk_set_phase(priv->sample_clk,
 		      TUNING_ITERATION_TO_PHASE(middle_phase,
 						priv->num_phases));

 free:
 	kfree(ranges);
 	return ret;
 }

 static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
 {
 	struct device_node *np = host->dev->of_node;
 	struct dw_mci_rockchip_priv_data *priv;

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

 	if (of_property_read_u32(np, "rockchip,desired-num-phases",
 					&priv->num_phases))
 		priv->num_phases = 360;

 	if (of_property_read_u32(np, "rockchip,default-sample-phase",
 					&priv->default_sample_phase))
 		priv->default_sample_phase = 0;

 	priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
 	if (IS_ERR(priv->drv_clk))
 		dev_dbg(host->dev, "ciu-drive not available\n");

 	priv->sample_clk = devm_clk_get(host->dev, "ciu-sample");
 	if (IS_ERR(priv->sample_clk))
 		dev_dbg(host->dev, "ciu-sample not available\n");

 	host->priv = priv;

 	return 0;
 }

 static int dw_mci_rockchip_init(struct dw_mci *host)
 {
 	int ret, i;

 	/* It is slot 8 on Rockchip SoCs */
 	host->sdio_id0 = 8;

 	if (of_device_is_compatible(host->dev->of_node, "rockchip,rk3288-dw-mshc")) {
 		host->bus_hz /= RK3288_CLKGEN_DIV;

 		/* clock driver will fail if the clock is less than the lowest source clock
 		 * divided by the internal clock divider. Test for the lowest available
 		 * clock and set the minimum freq to clock / clock divider.
 		 */

 		for (i = 0; i < ARRAY_SIZE(freqs); i++) {
 			ret = clk_round_rate(host->ciu_clk, freqs[i] * RK3288_CLKGEN_DIV);
 			if (ret > 0) {
 				host->minimum_speed = ret / RK3288_CLKGEN_DIV;
 				break;
 			}
 		}
 		if (ret < 0)
 			dev_warn(host->dev, "no valid minimum freq: %d\n", ret);
 	}

 	return 0;
 }

 static const struct dw_mci_drv_data rk2928_drv_data = {
 	.init			= dw_mci_rockchip_init,
 };

 static const struct dw_mci_drv_data rk3288_drv_data = {
 	.common_caps		= MMC_CAP_CMD23,
 	.set_ios		= dw_mci_rk3288_set_ios,
 	.execute_tuning		= dw_mci_rk3288_execute_tuning,
 	.parse_dt		= dw_mci_rk3288_parse_dt,
 	.init			= dw_mci_rockchip_init,
 };

 static const struct of_device_id dw_mci_rockchip_match[] = {
 	{ .compatible = "rockchip,rk2928-dw-mshc",
 		.data = &rk2928_drv_data },
 	{ .compatible = "rockchip,rk3288-dw-mshc",
 		.data = &rk3288_drv_data },
 	{},
 };
 MODULE_DEVICE_TABLE(of, dw_mci_rockchip_match);

 static int dw_mci_rockchip_probe(struct platform_device *pdev)
 {
 	const struct dw_mci_drv_data *drv_data;
 	const struct of_device_id *match;
 	int ret;

 	if (!pdev->dev.of_node)
 		return -ENODEV;

 	match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node);
 	drv_data = match->data;

 	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
 	pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
 	pm_runtime_use_autosuspend(&pdev->dev);

 	ret = dw_mci_pltfm_register(pdev, drv_data);
 	if (ret) {
 		pm_runtime_disable(&pdev->dev);
 		pm_runtime_set_suspended(&pdev->dev);
 		pm_runtime_put_noidle(&pdev->dev);
 		return ret;
 	}

 	pm_runtime_put_autosuspend(&pdev->dev);

 	return 0;
 }

 static int dw_mci_rockchip_remove(struct platform_device *pdev)
 {
 	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_put_noidle(&pdev->dev);

 	dw_mci_pltfm_remove(pdev);

 	return 0;
 }

 static const struct dev_pm_ops dw_mci_rockchip_dev_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
 				pm_runtime_force_resume)
 	SET_RUNTIME_PM_OPS(dw_mci_runtime_suspend,
 			   dw_mci_runtime_resume,
 			   NULL)
 };

 static struct platform_driver dw_mci_rockchip_pltfm_driver = {
 	.probe		= dw_mci_rockchip_probe,
 	.remove		= dw_mci_rockchip_remove,
 	.driver		= {
 		.name		= "dwmmc_rockchip",
 		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
 		.of_match_table	= dw_mci_rockchip_match,
 		.pm		= &dw_mci_rockchip_dev_pm_ops,
 	},
 };

 module_platform_driver(dw_mci_rockchip_pltfm_driver);

 MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
 MODULE_DESCRIPTION("Rockchip Specific DW-MSHC Driver Extension");
 MODULE_ALIAS("platform:dwmmc_rockchip");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
	*/

	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/clk.h>
	#include <linux/mmc/host.h>
	#include <linux/of_address.h>
	#include <linux/mmc/slot-gpio.h>
	#include <linux/pm_runtime.h>
	#include <linux/slab.h>

	#include "dw_mmc.h"
	#include "dw_mmc-pltfm.h"

	#define RK3288_CLKGEN_DIV 2

	static const unsigned int freqs[] = { 100000, 200000, 300000, 400000 };

	struct dw_mci_rockchip_priv_data {
	struct clk *drv_clk;
	struct clk *sample_clk;
	int default_sample_phase;
	int num_phases;
	};

	static void dw_mci_rk3288_set_ios(struct dw_mci host, struct mmc_ios ios)
	{
	struct dw_mci_rockchip_priv_data *priv = host->priv;
	int ret;
	unsigned int cclkin;
	u32 bus_hz;

	if (ios->clock == 0)
	return;

	/*
	* cclkin: source clock of mmc controller
	* bus_hz: card interface clock generated by CLKGEN
	* bus_hz = cclkin / RK3288_CLKGEN_DIV
	* ios->clock = (div == 0) ? bus_hz : (bus_hz / (2 * div))
	*
	* Note: div can only be 0 or 1, but div must be set to 1 for eMMC
	* DDR52 8-bit mode.
	*/
	if (ios->bus_width == MMC_BUS_WIDTH_8 &&
	ios->timing == MMC_TIMING_MMC_DDR52)
	cclkin = 2 * ios->clock * RK3288_CLKGEN_DIV;
	else
	cclkin = ios->clock * RK3288_CLKGEN_DIV;

	ret = clk_set_rate(host->ciu_clk, cclkin);
	if (ret)
	dev_warn(host->dev, "failed to set rate %uHz err: %d\n", cclkin, ret);

	bus_hz = clk_get_rate(host->ciu_clk) / RK3288_CLKGEN_DIV;
	if (bus_hz != host->bus_hz) {
	host->bus_hz = bus_hz;
	/* force dw_mci_setup_bus() */
	host->current_speed = 0;
	}

	/* Make sure we use phases which we can enumerate with */
	if (!IS_ERR(priv->sample_clk) && ios->timing <= MMC_TIMING_SD_HS)
	clk_set_phase(priv->sample_clk, priv->default_sample_phase);

	/*
	* Set the drive phase offset based on speed mode to achieve hold times.
	*
	* NOTE: this is _not_ a value that is dynamically tuned and is also
	* _not_ a value that will vary from board to board. It is a value
	* that could vary between different SoC models if they had massively
	* different output clock delays inside their dw_mmc IP block (delay_o),
	* but since it's OK to overshoot a little we don't need to do complex
	* calculations and can pick values that will just work for everyone.
	*
	* When picking values we'll stick with picking 0/90/180/270 since
	* those can be made very accurately on all known Rockchip SoCs.
	*
	* Note that these values match values from the DesignWare Databook
	* tables for the most part except for SDR12 and "ID mode". For those
	* two modes the databook calculations assume a clock in of 50MHz. As
	* seen above, we always use a clock in rate that is exactly the
	* card's input clock (times RK3288_CLKGEN_DIV, but that gets divided
	* back out before the controller sees it).
	*
	* From measurement of a single device, it appears that delay_o is
	* about .5 ns. Since we try to leave a bit of margin, it's expected
	* that numbers here will be fine even with much larger delay_o
	* (the 1.4 ns assumed by the DesignWare Databook would result in the
	* same results, for instance).
	*/
	if (!IS_ERR(priv->drv_clk)) {
	int phase;

	/*
	* In almost all cases a 90 degree phase offset will provide
	* sufficient hold times across all valid input clock rates
	* assuming delay_o is not absurd for a given SoC. We'll use
	* that as a default.
	*/
	phase = 90;

	switch (ios->timing) {
	case MMC_TIMING_MMC_DDR52:
	/*
	* Since clock in rate with MMC_DDR52 is doubled when
	* bus width is 8 we need to double the phase offset
	* to get the same timings.
	*/
	if (ios->bus_width == MMC_BUS_WIDTH_8)
	phase = 180;
	break;
	case MMC_TIMING_UHS_SDR104:
	case MMC_TIMING_MMC_HS200:
	/*
	* In the case of 150 MHz clock (typical max for
	* Rockchip SoCs), 90 degree offset will add a delay
	* of 1.67 ns. That will meet min hold time of .8 ns
	* as long as clock output delay is < .87 ns. On
	* SoCs measured this seems to be OK, but it doesn't
	* hurt to give margin here, so we use 180.
	*/
	phase = 180;
	break;
	}

	clk_set_phase(priv->drv_clk, phase);
	}
	}

	#define TUNING_ITERATION_TO_PHASE(i, num_phases) \
	(DIV_ROUND_UP((i) * 360, num_phases))

	static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
	{
	struct dw_mci *host = slot->host;
	struct dw_mci_rockchip_priv_data *priv = host->priv;
	struct mmc_host *mmc = slot->mmc;
	int ret = 0;
	int i;
	bool v, prev_v = 0, first_v;
	struct range_t {
	int start;
	int end; /* inclusive */
	};
	struct range_t *ranges;
	unsigned int range_count = 0;
	int longest_range_len = -1;
	int longest_range = -1;
	int middle_phase;

	if (IS_ERR(priv->sample_clk)) {
	dev_err(host->dev, "Tuning clock (sample_clk) not defined.\n");
	return -EIO;
	}

	ranges = kmalloc_array(priv->num_phases / 2 + 1,
	sizeof(*ranges), GFP_KERNEL);
	if (!ranges)
	return -ENOMEM;

	/* Try each phase and extract good ranges */
	for (i = 0; i < priv->num_phases; ) {
	clk_set_phase(priv->sample_clk,
	TUNING_ITERATION_TO_PHASE(i, priv->num_phases));

	v = !mmc_send_tuning(mmc, opcode, NULL);

	if (i == 0)
	first_v = v;

	if ((!prev_v) && v) {
	range_count++;
	ranges[range_count-1].start = i;
	}
	if (v) {
	ranges[range_count-1].end = i;
	i++;
	} else if (i == priv->num_phases - 1) {
	/* No extra skipping rules if we're at the end */
	i++;
	} else {
	/*
	* No need to check too close to an invalid
	* one since testing bad phases is slow. Skip
	* 20 degrees.
	*/
	i += DIV_ROUND_UP(20 * priv->num_phases, 360);

	/* Always test the last one */
	if (i >= priv->num_phases)
	i = priv->num_phases - 1;
	}

	prev_v = v;
	}

	if (range_count == 0) {
	dev_warn(host->dev, "All phases bad!");
	ret = -EIO;
	goto free;
	}

	/* wrap around case, merge the end points */
	if ((range_count > 1) && first_v && v) {
	ranges[0].start = ranges[range_count-1].start;
	range_count--;
	}

	if (ranges[0].start == 0 && ranges[0].end == priv->num_phases - 1) {
	clk_set_phase(priv->sample_clk, priv->default_sample_phase);
	dev_info(host->dev, "All phases work, using default phase %d.",
	priv->default_sample_phase);
	goto free;
	}

	/* Find the longest range */
	for (i = 0; i < range_count; i++) {
	int len = (ranges[i].end - ranges[i].start + 1);

	if (len < 0)
	len += priv->num_phases;

	if (longest_range_len < len) {
	longest_range_len = len;
	longest_range = i;
	}

	dev_dbg(host->dev, "Good phase range %d-%d (%d len)\n",
	TUNING_ITERATION_TO_PHASE(ranges[i].start,
	priv->num_phases),
	TUNING_ITERATION_TO_PHASE(ranges[i].end,
	priv->num_phases),
	len
	);
	}

	dev_dbg(host->dev, "Best phase range %d-%d (%d len)\n",
	TUNING_ITERATION_TO_PHASE(ranges[longest_range].start,
	priv->num_phases),
	TUNING_ITERATION_TO_PHASE(ranges[longest_range].end,
	priv->num_phases),
	longest_range_len
	);

	middle_phase = ranges[longest_range].start + longest_range_len / 2;
	middle_phase %= priv->num_phases;
	dev_info(host->dev, "Successfully tuned phase to %d\n",
	TUNING_ITERATION_TO_PHASE(middle_phase, priv->num_phases));

	clk_set_phase(priv->sample_clk,
	TUNING_ITERATION_TO_PHASE(middle_phase,
	priv->num_phases));

	free:
	kfree(ranges);
	return ret;
	}

	static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
	{
	struct device_node *np = host->dev->of_node;
	struct dw_mci_rockchip_priv_data *priv;

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

	if (of_property_read_u32(np, "rockchip,desired-num-phases",
	&priv->num_phases))
	priv->num_phases = 360;

	if (of_property_read_u32(np, "rockchip,default-sample-phase",
	&priv->default_sample_phase))
	priv->default_sample_phase = 0;

	priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
	if (IS_ERR(priv->drv_clk))
	dev_dbg(host->dev, "ciu-drive not available\n");

	priv->sample_clk = devm_clk_get(host->dev, "ciu-sample");
	if (IS_ERR(priv->sample_clk))
	dev_dbg(host->dev, "ciu-sample not available\n");

	host->priv = priv;

	return 0;
	}

	static int dw_mci_rockchip_init(struct dw_mci *host)
	{
	int ret, i;

	/* It is slot 8 on Rockchip SoCs */
	host->sdio_id0 = 8;

	if (of_device_is_compatible(host->dev->of_node, "rockchip,rk3288-dw-mshc")) {
	host->bus_hz /= RK3288_CLKGEN_DIV;

	/* clock driver will fail if the clock is less than the lowest source clock
	* divided by the internal clock divider. Test for the lowest available
	* clock and set the minimum freq to clock / clock divider.
	*/

	for (i = 0; i < ARRAY_SIZE(freqs); i++) {
	ret = clk_round_rate(host->ciu_clk, freqs[i] * RK3288_CLKGEN_DIV);
	if (ret > 0) {
	host->minimum_speed = ret / RK3288_CLKGEN_DIV;
	break;
	}
	}
	if (ret < 0)
	dev_warn(host->dev, "no valid minimum freq: %d\n", ret);
	}

	return 0;
	}

	static const struct dw_mci_drv_data rk2928_drv_data = {
	.init = dw_mci_rockchip_init,
	};

	static const struct dw_mci_drv_data rk3288_drv_data = {
	.common_caps = MMC_CAP_CMD23,
	.set_ios = dw_mci_rk3288_set_ios,
	.execute_tuning = dw_mci_rk3288_execute_tuning,
	.parse_dt = dw_mci_rk3288_parse_dt,
	.init = dw_mci_rockchip_init,
	};

	static const struct of_device_id dw_mci_rockchip_match[] = {
	{ .compatible = "rockchip,rk2928-dw-mshc",
	.data = &rk2928_drv_data },
	{ .compatible = "rockchip,rk3288-dw-mshc",
	.data = &rk3288_drv_data },
	{},
	};
	MODULE_DEVICE_TABLE(of, dw_mci_rockchip_match);

	static int dw_mci_rockchip_probe(struct platform_device *pdev)
	{
	const struct dw_mci_drv_data *drv_data;
	const struct of_device_id *match;
	int ret;

	if (!pdev->dev.of_node)
	return -ENODEV;

	match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node);
	drv_data = match->data;

	pm_runtime_get_noresume(&pdev->dev);
	pm_runtime_set_active(&pdev->dev);
	pm_runtime_enable(&pdev->dev);
	pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
	pm_runtime_use_autosuspend(&pdev->dev);

	ret = dw_mci_pltfm_register(pdev, drv_data);
	if (ret) {
	pm_runtime_disable(&pdev->dev);
	pm_runtime_set_suspended(&pdev->dev);
	pm_runtime_put_noidle(&pdev->dev);
	return ret;
	}

	pm_runtime_put_autosuspend(&pdev->dev);

	return 0;
	}

	static int dw_mci_rockchip_remove(struct platform_device *pdev)
	{
	pm_runtime_get_sync(&pdev->dev);
	pm_runtime_disable(&pdev->dev);
	pm_runtime_put_noidle(&pdev->dev);

	dw_mci_pltfm_remove(pdev);

	return 0;
	}

	static const struct dev_pm_ops dw_mci_rockchip_dev_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
	pm_runtime_force_resume)
	SET_RUNTIME_PM_OPS(dw_mci_runtime_suspend,
	dw_mci_runtime_resume,
	NULL)
	};

	static struct platform_driver dw_mci_rockchip_pltfm_driver = {
	.probe = dw_mci_rockchip_probe,
	.remove = dw_mci_rockchip_remove,
	.driver = {
	.name = "dwmmc_rockchip",
	.probe_type = PROBE_PREFER_ASYNCHRONOUS,
	.of_match_table = dw_mci_rockchip_match,
	.pm = &dw_mci_rockchip_dev_pm_ops,
	},
	};

	module_platform_driver(dw_mci_rockchip_pltfm_driver);

	MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
	MODULE_DESCRIPTION("Rockchip Specific DW-MSHC Driver Extension");
	MODULE_ALIAS("platform:dwmmc_rockchip");
	MODULE_LICENSE("GPL v2");