drivers/bus/qcom-ebi2.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Qualcomm External Bus Interface 2 (EBI2) driver
  * an older version of the Qualcomm Parallel Interface Controller (QPIC)
  *
  * Copyright (C) 2016 Linaro Ltd.
  *
  * Author: Linus Walleij <linus.walleij@linaro.org>
  *
  * See the device tree bindings for this block for more details on the
  * hardware.
  */

 #include <linux/module.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/platform_device.h>
 #include <linux/bitops.h>

 /*
  * CS0, CS1, CS4 and CS5 are two bits wide, CS2 and CS3 are one bit.
  */
 #define EBI2_CS0_ENABLE_MASK BIT(0)|BIT(1)
 #define EBI2_CS1_ENABLE_MASK BIT(2)|BIT(3)
 #define EBI2_CS2_ENABLE_MASK BIT(4)
 #define EBI2_CS3_ENABLE_MASK BIT(5)
 #define EBI2_CS4_ENABLE_MASK BIT(6)|BIT(7)
 #define EBI2_CS5_ENABLE_MASK BIT(8)|BIT(9)
 #define EBI2_CSN_MASK GENMASK(9, 0)

 #define EBI2_XMEM_CFG 0x0000 /* Power management etc */

 /*
  * SLOW CSn CFG
  *
  * Bits 31-28: RECOVERY recovery cycles (0 = 1, 1 = 2 etc) this is the time the
  *             memory continues to drive the data bus after OE is de-asserted.
  *             Inserted when reading one CS and switching to another CS or read
  *             followed by write on the same CS. Valid values 0 thru 15.
  * Bits 27-24: WR_HOLD write hold cycles, these are extra cycles inserted after
  *             every write minimum 1. The data out is driven from the time WE is
  *             asserted until CS is asserted. With a hold of 1, the CS stays
  *             active for 1 extra cycle etc. Valid values 0 thru 15.
  * Bits 23-16: WR_DELTA initial latency for write cycles inserted for the first
  *             write to a page or burst memory
  * Bits 15-8:  RD_DELTA initial latency for read cycles inserted for the first
  *             read to a page or burst memory
  * Bits 7-4:   WR_WAIT number of wait cycles for every write access, 0=1 cycle
  *             so 1 thru 16 cycles.
  * Bits 3-0:   RD_WAIT number of wait cycles for every read access, 0=1 cycle
  *             so 1 thru 16 cycles.
  */
 #define EBI2_XMEM_CS0_SLOW_CFG 0x0008
 #define EBI2_XMEM_CS1_SLOW_CFG 0x000C
 #define EBI2_XMEM_CS2_SLOW_CFG 0x0010
 #define EBI2_XMEM_CS3_SLOW_CFG 0x0014
 #define EBI2_XMEM_CS4_SLOW_CFG 0x0018
 #define EBI2_XMEM_CS5_SLOW_CFG 0x001C

 #define EBI2_XMEM_RECOVERY_SHIFT	28
 #define EBI2_XMEM_WR_HOLD_SHIFT		24
 #define EBI2_XMEM_WR_DELTA_SHIFT	16
 #define EBI2_XMEM_RD_DELTA_SHIFT	8
 #define EBI2_XMEM_WR_WAIT_SHIFT		4
 #define EBI2_XMEM_RD_WAIT_SHIFT		0

 /*
  * FAST CSn CFG
  * Bits 31-28: ?
  * Bits 27-24: RD_HOLD: the length in cycles of the first segment of a read
  *             transfer. For a single read trandfer this will be the time
  *             from CS assertion to OE assertion.
  * Bits 18-24: ?
  * Bits 17-16: ADV_OE_RECOVERY, the number of cycles elapsed before an OE
  *             assertion, with respect to the cycle where ADV is asserted.
  *             2 means 2 cycles between ADV and OE. Values 0, 1, 2 or 3.
  * Bits 5:     ADDR_HOLD_ENA, The address is held for an extra cycle to meet
  *             hold time requirements with ADV assertion.
  *
  * The manual mentions "write precharge cycles" and "precharge cycles".
  * We have not been able to figure out which bit fields these correspond to
  * in the hardware, or what valid values exist. The current hypothesis is that
  * this is something just used on the FAST chip selects. There is also a "byte
  * device enable" flag somewhere for 8bit memories.
  */
 #define EBI2_XMEM_CS0_FAST_CFG 0x0028
 #define EBI2_XMEM_CS1_FAST_CFG 0x002C
 #define EBI2_XMEM_CS2_FAST_CFG 0x0030
 #define EBI2_XMEM_CS3_FAST_CFG 0x0034
 #define EBI2_XMEM_CS4_FAST_CFG 0x0038
 #define EBI2_XMEM_CS5_FAST_CFG 0x003C

 #define EBI2_XMEM_RD_HOLD_SHIFT		24
 #define EBI2_XMEM_ADV_OE_RECOVERY_SHIFT	16
 #define EBI2_XMEM_ADDR_HOLD_ENA_SHIFT	5

 /**
  * struct cs_data - struct with info on a chipselect setting
  * @enable_mask: mask to enable the chipselect in the EBI2 config
  * @slow_cfg0: offset to XMEMC slow CS config
  * @fast_cfg1: offset to XMEMC fast CS config
  */
 struct cs_data {
 	u32 enable_mask;
 	u16 slow_cfg;
 	u16 fast_cfg;
 };

 static const struct cs_data cs_info[] = {
 	{
 		/* CS0 */
 		.enable_mask = EBI2_CS0_ENABLE_MASK,
 		.slow_cfg = EBI2_XMEM_CS0_SLOW_CFG,
 		.fast_cfg = EBI2_XMEM_CS0_FAST_CFG,
 	},
 	{
 		/* CS1 */
 		.enable_mask = EBI2_CS1_ENABLE_MASK,
 		.slow_cfg = EBI2_XMEM_CS1_SLOW_CFG,
 		.fast_cfg = EBI2_XMEM_CS1_FAST_CFG,
 	},
 	{
 		/* CS2 */
 		.enable_mask = EBI2_CS2_ENABLE_MASK,
 		.slow_cfg = EBI2_XMEM_CS2_SLOW_CFG,
 		.fast_cfg = EBI2_XMEM_CS2_FAST_CFG,
 	},
 	{
 		/* CS3 */
 		.enable_mask = EBI2_CS3_ENABLE_MASK,
 		.slow_cfg = EBI2_XMEM_CS3_SLOW_CFG,
 		.fast_cfg = EBI2_XMEM_CS3_FAST_CFG,
 	},
 	{
 		/* CS4 */
 		.enable_mask = EBI2_CS4_ENABLE_MASK,
 		.slow_cfg = EBI2_XMEM_CS4_SLOW_CFG,
 		.fast_cfg = EBI2_XMEM_CS4_FAST_CFG,
 	},
 	{
 		/* CS5 */
 		.enable_mask = EBI2_CS5_ENABLE_MASK,
 		.slow_cfg = EBI2_XMEM_CS5_SLOW_CFG,
 		.fast_cfg = EBI2_XMEM_CS5_FAST_CFG,
 	},
 };

 /**
  * struct ebi2_xmem_prop - describes an XMEM config property
  * @prop: the device tree binding name
  * @max: maximum value for the property
  * @slowreg: true if this property is in the SLOW CS config register
  * else it is assumed to be in the FAST config register
  * @shift: the bit field start in the SLOW or FAST register for this
  * property
  */
 struct ebi2_xmem_prop {
 	const char *prop;
 	u32 max;
 	bool slowreg;
 	u16 shift;
 };

 static const struct ebi2_xmem_prop xmem_props[] = {
 	{
 		.prop = "qcom,xmem-recovery-cycles",
 		.max = 15,
 		.slowreg = true,
 		.shift = EBI2_XMEM_RECOVERY_SHIFT,
 	},
 	{
 		.prop = "qcom,xmem-write-hold-cycles",
 		.max = 15,
 		.slowreg = true,
 		.shift = EBI2_XMEM_WR_HOLD_SHIFT,
 	},
 	{
 		.prop = "qcom,xmem-write-delta-cycles",
 		.max = 255,
 		.slowreg = true,
 		.shift = EBI2_XMEM_WR_DELTA_SHIFT,
 	},
 	{
 		.prop = "qcom,xmem-read-delta-cycles",
 		.max = 255,
 		.slowreg = true,
 		.shift = EBI2_XMEM_RD_DELTA_SHIFT,
 	},
 	{
 		.prop = "qcom,xmem-write-wait-cycles",
 		.max = 15,
 		.slowreg = true,
 		.shift = EBI2_XMEM_WR_WAIT_SHIFT,
 	},
 	{
 		.prop = "qcom,xmem-read-wait-cycles",
 		.max = 15,
 		.slowreg = true,
 		.shift = EBI2_XMEM_RD_WAIT_SHIFT,
 	},
 	{
 		.prop = "qcom,xmem-address-hold-enable",
 		.max = 1, /* boolean prop */
 		.slowreg = false,
 		.shift = EBI2_XMEM_ADDR_HOLD_ENA_SHIFT,
 	},
 	{
 		.prop = "qcom,xmem-adv-to-oe-recovery-cycles",
 		.max = 3,
 		.slowreg = false,
 		.shift = EBI2_XMEM_ADV_OE_RECOVERY_SHIFT,
 	},
 	{
 		.prop = "qcom,xmem-read-hold-cycles",
 		.max = 15,
 		.slowreg = false,
 		.shift = EBI2_XMEM_RD_HOLD_SHIFT,
 	},
 };

 static void qcom_ebi2_setup_chipselect(struct device_node *np,
 				       struct device *dev,
 				       void __iomem *ebi2_base,
 				       void __iomem *ebi2_xmem,
 				       u32 csindex)
 {
 	const struct cs_data *csd;
 	u32 slowcfg, fastcfg;
 	u32 val;
 	int ret;
 	int i;

 	csd = &cs_info[csindex];
 	val = readl(ebi2_base);
 	val |= csd->enable_mask;
 	writel(val, ebi2_base);
 	dev_dbg(dev, "enabled CS%u\n", csindex);

 	/* Next set up the XMEMC */
 	slowcfg = 0;
 	fastcfg = 0;

 	for (i = 0; i < ARRAY_SIZE(xmem_props); i++) {
 		const struct ebi2_xmem_prop *xp = &xmem_props[i];

 		/* All are regular u32 values */
 		ret = of_property_read_u32(np, xp->prop, &val);
 		if (ret) {
 			dev_dbg(dev, "could not read %s for CS%d\n",
 				xp->prop, csindex);
 			continue;
 		}

 		/* First check boolean props */
 		if (xp->max == 1 && val) {
 			if (xp->slowreg)
 				slowcfg |= BIT(xp->shift);
 			else
 				fastcfg |= BIT(xp->shift);
 			dev_dbg(dev, "set %s flag\n", xp->prop);
 			continue;
 		}

 		/* We're dealing with an u32 */
 		if (val > xp->max) {
 			dev_err(dev,
 				"too high value for %s: %u, capped at %u\n",
 				xp->prop, val, xp->max);
 			val = xp->max;
 		}
 		if (xp->slowreg)
 			slowcfg |= (val << xp->shift);
 		else
 			fastcfg |= (val << xp->shift);
 		dev_dbg(dev, "set %s to %u\n", xp->prop, val);
 	}

 	dev_info(dev, "CS%u: SLOW CFG 0x%08x, FAST CFG 0x%08x\n",
 		 csindex, slowcfg, fastcfg);

 	if (slowcfg)
 		writel(slowcfg, ebi2_xmem + csd->slow_cfg);
 	if (fastcfg)
 		writel(fastcfg, ebi2_xmem + csd->fast_cfg);
 }

 static int qcom_ebi2_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct device_node *child;
 	struct device *dev = &pdev->dev;
 	struct resource *res;
 	void __iomem *ebi2_base;
 	void __iomem *ebi2_xmem;
 	struct clk *ebi2xclk;
 	struct clk *ebi2clk;
 	bool have_children = false;
 	u32 val;
 	int ret;

 	ebi2xclk = devm_clk_get(dev, "ebi2x");
 	if (IS_ERR(ebi2xclk))
 		return PTR_ERR(ebi2xclk);

 	ret = clk_prepare_enable(ebi2xclk);
 	if (ret) {
 		dev_err(dev, "could not enable EBI2X clk (%d)\n", ret);
 		return ret;
 	}

 	ebi2clk = devm_clk_get(dev, "ebi2");
 	if (IS_ERR(ebi2clk)) {
 		ret = PTR_ERR(ebi2clk);
 		goto err_disable_2x_clk;
 	}

 	ret = clk_prepare_enable(ebi2clk);
 	if (ret) {
 		dev_err(dev, "could not enable EBI2 clk\n");
 		goto err_disable_2x_clk;
 	}

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	ebi2_base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(ebi2_base)) {
 		ret = PTR_ERR(ebi2_base);
 		goto err_disable_clk;
 	}

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 	ebi2_xmem = devm_ioremap_resource(dev, res);
 	if (IS_ERR(ebi2_xmem)) {
 		ret = PTR_ERR(ebi2_xmem);
 		goto err_disable_clk;
 	}

 	/* Allegedly this turns the power save mode off */
 	writel(0UL, ebi2_xmem + EBI2_XMEM_CFG);

 	/* Disable all chipselects */
 	val = readl(ebi2_base);
 	val &= ~EBI2_CSN_MASK;
 	writel(val, ebi2_base);

 	/* Walk over the child nodes and see what chipselects we use */
 	for_each_available_child_of_node(np, child) {
 		u32 csindex;

 		/* Figure out the chipselect */
 		ret = of_property_read_u32(child, "reg", &csindex);
 		if (ret) {
 			of_node_put(child);
 			return ret;
 		}

 		if (csindex > 5) {
 			dev_err(dev,
 				"invalid chipselect %u, we only support 0-5\n",
 				csindex);
 			continue;
 		}

 		qcom_ebi2_setup_chipselect(child,
 					   dev,
 					   ebi2_base,
 					   ebi2_xmem,
 					   csindex);

 		/* We have at least one child */
 		have_children = true;
 	}

 	if (have_children)
 		return of_platform_default_populate(np, NULL, dev);
 	return 0;

 err_disable_clk:
 	clk_disable_unprepare(ebi2clk);
 err_disable_2x_clk:
 	clk_disable_unprepare(ebi2xclk);

 	return ret;
 }

 static const struct of_device_id qcom_ebi2_of_match[] = {
 	{ .compatible = "qcom,msm8660-ebi2", },
 	{ .compatible = "qcom,apq8060-ebi2", },
 	{ }
 };

 static struct platform_driver qcom_ebi2_driver = {
 	.probe = qcom_ebi2_probe,
 	.driver = {
 		.name = "qcom-ebi2",
 		.of_match_table = qcom_ebi2_of_match,
 	},
 };
 module_platform_driver(qcom_ebi2_driver);
 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 MODULE_DESCRIPTION("Qualcomm EBI2 driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Qualcomm External Bus Interface 2 (EBI2) driver
	* an older version of the Qualcomm Parallel Interface Controller (QPIC)
	*
	* Copyright (C) 2016 Linaro Ltd.
	*
	* Author: Linus Walleij <linus.walleij@linaro.org>
	*
	* See the device tree bindings for this block for more details on the
	* hardware.
	*/

	#include <linux/module.h>
	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/of.h>
	#include <linux/of_platform.h>
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <linux/platform_device.h>
	#include <linux/bitops.h>

	/*
	* CS0, CS1, CS4 and CS5 are two bits wide, CS2 and CS3 are one bit.
	*/
	#define EBI2_CS0_ENABLE_MASK BIT(0)\|BIT(1)
	#define EBI2_CS1_ENABLE_MASK BIT(2)\|BIT(3)
	#define EBI2_CS2_ENABLE_MASK BIT(4)
	#define EBI2_CS3_ENABLE_MASK BIT(5)
	#define EBI2_CS4_ENABLE_MASK BIT(6)\|BIT(7)
	#define EBI2_CS5_ENABLE_MASK BIT(8)\|BIT(9)
	#define EBI2_CSN_MASK GENMASK(9, 0)

	#define EBI2_XMEM_CFG 0x0000 /* Power management etc */

	/*
	* SLOW CSn CFG
	*
	* Bits 31-28: RECOVERY recovery cycles (0 = 1, 1 = 2 etc) this is the time the
	* memory continues to drive the data bus after OE is de-asserted.
	* Inserted when reading one CS and switching to another CS or read
	* followed by write on the same CS. Valid values 0 thru 15.
	* Bits 27-24: WR_HOLD write hold cycles, these are extra cycles inserted after
	* every write minimum 1. The data out is driven from the time WE is
	* asserted until CS is asserted. With a hold of 1, the CS stays
	* active for 1 extra cycle etc. Valid values 0 thru 15.
	* Bits 23-16: WR_DELTA initial latency for write cycles inserted for the first
	* write to a page or burst memory
	* Bits 15-8: RD_DELTA initial latency for read cycles inserted for the first
	* read to a page or burst memory
	* Bits 7-4: WR_WAIT number of wait cycles for every write access, 0=1 cycle
	* so 1 thru 16 cycles.
	* Bits 3-0: RD_WAIT number of wait cycles for every read access, 0=1 cycle
	* so 1 thru 16 cycles.
	*/
	#define EBI2_XMEM_CS0_SLOW_CFG 0x0008
	#define EBI2_XMEM_CS1_SLOW_CFG 0x000C
	#define EBI2_XMEM_CS2_SLOW_CFG 0x0010
	#define EBI2_XMEM_CS3_SLOW_CFG 0x0014
	#define EBI2_XMEM_CS4_SLOW_CFG 0x0018
	#define EBI2_XMEM_CS5_SLOW_CFG 0x001C

	#define EBI2_XMEM_RECOVERY_SHIFT 28
	#define EBI2_XMEM_WR_HOLD_SHIFT 24
	#define EBI2_XMEM_WR_DELTA_SHIFT 16
	#define EBI2_XMEM_RD_DELTA_SHIFT 8
	#define EBI2_XMEM_WR_WAIT_SHIFT 4
	#define EBI2_XMEM_RD_WAIT_SHIFT 0

	/*
	* FAST CSn CFG
	* Bits 31-28: ?
	* Bits 27-24: RD_HOLD: the length in cycles of the first segment of a read
	* transfer. For a single read trandfer this will be the time
	* from CS assertion to OE assertion.
	* Bits 18-24: ?
	* Bits 17-16: ADV_OE_RECOVERY, the number of cycles elapsed before an OE
	* assertion, with respect to the cycle where ADV is asserted.
	* 2 means 2 cycles between ADV and OE. Values 0, 1, 2 or 3.
	* Bits 5: ADDR_HOLD_ENA, The address is held for an extra cycle to meet
	* hold time requirements with ADV assertion.
	*
	* The manual mentions "write precharge cycles" and "precharge cycles".
	* We have not been able to figure out which bit fields these correspond to
	* in the hardware, or what valid values exist. The current hypothesis is that
	* this is something just used on the FAST chip selects. There is also a "byte
	* device enable" flag somewhere for 8bit memories.
	*/
	#define EBI2_XMEM_CS0_FAST_CFG 0x0028
	#define EBI2_XMEM_CS1_FAST_CFG 0x002C
	#define EBI2_XMEM_CS2_FAST_CFG 0x0030
	#define EBI2_XMEM_CS3_FAST_CFG 0x0034
	#define EBI2_XMEM_CS4_FAST_CFG 0x0038
	#define EBI2_XMEM_CS5_FAST_CFG 0x003C

	#define EBI2_XMEM_RD_HOLD_SHIFT 24
	#define EBI2_XMEM_ADV_OE_RECOVERY_SHIFT 16
	#define EBI2_XMEM_ADDR_HOLD_ENA_SHIFT 5

	/**
	* struct cs_data - struct with info on a chipselect setting
	* @enable_mask: mask to enable the chipselect in the EBI2 config
	* @slow_cfg0: offset to XMEMC slow CS config
	* @fast_cfg1: offset to XMEMC fast CS config
	*/
	struct cs_data {
	u32 enable_mask;
	u16 slow_cfg;
	u16 fast_cfg;
	};

	static const struct cs_data cs_info[] = {
	{
	/* CS0 */
	.enable_mask = EBI2_CS0_ENABLE_MASK,
	.slow_cfg = EBI2_XMEM_CS0_SLOW_CFG,
	.fast_cfg = EBI2_XMEM_CS0_FAST_CFG,
	},
	{
	/* CS1 */
	.enable_mask = EBI2_CS1_ENABLE_MASK,
	.slow_cfg = EBI2_XMEM_CS1_SLOW_CFG,
	.fast_cfg = EBI2_XMEM_CS1_FAST_CFG,
	},
	{
	/* CS2 */
	.enable_mask = EBI2_CS2_ENABLE_MASK,
	.slow_cfg = EBI2_XMEM_CS2_SLOW_CFG,
	.fast_cfg = EBI2_XMEM_CS2_FAST_CFG,
	},
	{
	/* CS3 */
	.enable_mask = EBI2_CS3_ENABLE_MASK,
	.slow_cfg = EBI2_XMEM_CS3_SLOW_CFG,
	.fast_cfg = EBI2_XMEM_CS3_FAST_CFG,
	},
	{
	/* CS4 */
	.enable_mask = EBI2_CS4_ENABLE_MASK,
	.slow_cfg = EBI2_XMEM_CS4_SLOW_CFG,
	.fast_cfg = EBI2_XMEM_CS4_FAST_CFG,
	},
	{
	/* CS5 */
	.enable_mask = EBI2_CS5_ENABLE_MASK,
	.slow_cfg = EBI2_XMEM_CS5_SLOW_CFG,
	.fast_cfg = EBI2_XMEM_CS5_FAST_CFG,
	},
	};

	/**
	* struct ebi2_xmem_prop - describes an XMEM config property
	* @prop: the device tree binding name
	* @max: maximum value for the property
	* @slowreg: true if this property is in the SLOW CS config register
	* else it is assumed to be in the FAST config register
	* @shift: the bit field start in the SLOW or FAST register for this
	* property
	*/
	struct ebi2_xmem_prop {
	const char *prop;
	u32 max;
	bool slowreg;
	u16 shift;
	};

	static const struct ebi2_xmem_prop xmem_props[] = {
	{
	.prop = "qcom,xmem-recovery-cycles",
	.max = 15,
	.slowreg = true,
	.shift = EBI2_XMEM_RECOVERY_SHIFT,
	},
	{
	.prop = "qcom,xmem-write-hold-cycles",
	.max = 15,
	.slowreg = true,
	.shift = EBI2_XMEM_WR_HOLD_SHIFT,
	},
	{
	.prop = "qcom,xmem-write-delta-cycles",
	.max = 255,
	.slowreg = true,
	.shift = EBI2_XMEM_WR_DELTA_SHIFT,
	},
	{
	.prop = "qcom,xmem-read-delta-cycles",
	.max = 255,
	.slowreg = true,
	.shift = EBI2_XMEM_RD_DELTA_SHIFT,
	},
	{
	.prop = "qcom,xmem-write-wait-cycles",
	.max = 15,
	.slowreg = true,
	.shift = EBI2_XMEM_WR_WAIT_SHIFT,
	},
	{
	.prop = "qcom,xmem-read-wait-cycles",
	.max = 15,
	.slowreg = true,
	.shift = EBI2_XMEM_RD_WAIT_SHIFT,
	},
	{
	.prop = "qcom,xmem-address-hold-enable",
	.max = 1, /* boolean prop */
	.slowreg = false,
	.shift = EBI2_XMEM_ADDR_HOLD_ENA_SHIFT,
	},
	{
	.prop = "qcom,xmem-adv-to-oe-recovery-cycles",
	.max = 3,
	.slowreg = false,
	.shift = EBI2_XMEM_ADV_OE_RECOVERY_SHIFT,
	},
	{
	.prop = "qcom,xmem-read-hold-cycles",
	.max = 15,
	.slowreg = false,
	.shift = EBI2_XMEM_RD_HOLD_SHIFT,
	},
	};

	static void qcom_ebi2_setup_chipselect(struct device_node *np,
	struct device *dev,
	void __iomem *ebi2_base,
	void __iomem *ebi2_xmem,
	u32 csindex)
	{
	const struct cs_data *csd;
	u32 slowcfg, fastcfg;
	u32 val;
	int ret;
	int i;

	csd = &cs_info[csindex];
	val = readl(ebi2_base);
	val \|= csd->enable_mask;
	writel(val, ebi2_base);
	dev_dbg(dev, "enabled CS%u\n", csindex);

	/* Next set up the XMEMC */
	slowcfg = 0;
	fastcfg = 0;

	for (i = 0; i < ARRAY_SIZE(xmem_props); i++) {
	const struct ebi2_xmem_prop *xp = &xmem_props[i];

	/* All are regular u32 values */
	ret = of_property_read_u32(np, xp->prop, &val);
	if (ret) {
	dev_dbg(dev, "could not read %s for CS%d\n",
	xp->prop, csindex);
	continue;
	}

	/* First check boolean props */
	if (xp->max == 1 && val) {
	if (xp->slowreg)
	slowcfg \|= BIT(xp->shift);
	else
	fastcfg \|= BIT(xp->shift);
	dev_dbg(dev, "set %s flag\n", xp->prop);
	continue;
	}

	/* We're dealing with an u32 */
	if (val > xp->max) {
	dev_err(dev,
	"too high value for %s: %u, capped at %u\n",
	xp->prop, val, xp->max);
	val = xp->max;
	}
	if (xp->slowreg)
	slowcfg \|= (val << xp->shift);
	else
	fastcfg \|= (val << xp->shift);
	dev_dbg(dev, "set %s to %u\n", xp->prop, val);
	}

	dev_info(dev, "CS%u: SLOW CFG 0x%08x, FAST CFG 0x%08x\n",
	csindex, slowcfg, fastcfg);

	if (slowcfg)
	writel(slowcfg, ebi2_xmem + csd->slow_cfg);
	if (fastcfg)
	writel(fastcfg, ebi2_xmem + csd->fast_cfg);
	}

	static int qcom_ebi2_probe(struct platform_device *pdev)
	{
	struct device_node *np = pdev->dev.of_node;
	struct device_node *child;
	struct device *dev = &pdev->dev;
	struct resource *res;
	void __iomem *ebi2_base;
	void __iomem *ebi2_xmem;
	struct clk *ebi2xclk;
	struct clk *ebi2clk;
	bool have_children = false;
	u32 val;
	int ret;

	ebi2xclk = devm_clk_get(dev, "ebi2x");
	if (IS_ERR(ebi2xclk))
	return PTR_ERR(ebi2xclk);

	ret = clk_prepare_enable(ebi2xclk);
	if (ret) {
	dev_err(dev, "could not enable EBI2X clk (%d)\n", ret);
	return ret;
	}

	ebi2clk = devm_clk_get(dev, "ebi2");
	if (IS_ERR(ebi2clk)) {
	ret = PTR_ERR(ebi2clk);
	goto err_disable_2x_clk;
	}

	ret = clk_prepare_enable(ebi2clk);
	if (ret) {
	dev_err(dev, "could not enable EBI2 clk\n");
	goto err_disable_2x_clk;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	ebi2_base = devm_ioremap_resource(dev, res);
	if (IS_ERR(ebi2_base)) {
	ret = PTR_ERR(ebi2_base);
	goto err_disable_clk;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	ebi2_xmem = devm_ioremap_resource(dev, res);
	if (IS_ERR(ebi2_xmem)) {
	ret = PTR_ERR(ebi2_xmem);
	goto err_disable_clk;
	}

	/* Allegedly this turns the power save mode off */
	writel(0UL, ebi2_xmem + EBI2_XMEM_CFG);

	/* Disable all chipselects */
	val = readl(ebi2_base);
	val &= ~EBI2_CSN_MASK;
	writel(val, ebi2_base);

	/* Walk over the child nodes and see what chipselects we use */
	for_each_available_child_of_node(np, child) {
	u32 csindex;

	/* Figure out the chipselect */
	ret = of_property_read_u32(child, "reg", &csindex);
	if (ret) {
	of_node_put(child);
	return ret;
	}

	if (csindex > 5) {
	dev_err(dev,
	"invalid chipselect %u, we only support 0-5\n",
	csindex);
	continue;
	}

	qcom_ebi2_setup_chipselect(child,
	dev,
	ebi2_base,
	ebi2_xmem,
	csindex);

	/* We have at least one child */
	have_children = true;
	}

	if (have_children)
	return of_platform_default_populate(np, NULL, dev);
	return 0;

	err_disable_clk:
	clk_disable_unprepare(ebi2clk);
	err_disable_2x_clk:
	clk_disable_unprepare(ebi2xclk);

	return ret;
	}

	static const struct of_device_id qcom_ebi2_of_match[] = {
	{ .compatible = "qcom,msm8660-ebi2", },
	{ .compatible = "qcom,apq8060-ebi2", },
	{ }
	};

	static struct platform_driver qcom_ebi2_driver = {
	.probe = qcom_ebi2_probe,
	.driver = {
	.name = "qcom-ebi2",
	.of_match_table = qcom_ebi2_of_match,
	},
	};
	module_platform_driver(qcom_ebi2_driver);
	MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
	MODULE_DESCRIPTION("Qualcomm EBI2 driver");
	MODULE_LICENSE("GPL");