drivers/power/avs/rockchip-io-domain.c - arm/linux - Git at Google

 /*
  * Rockchip IO Voltage Domain driver
  *
  * Copyright 2014 MundoReader S.L.
  * Copyright 2014 Google, Inc.
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
  * may be copied, distributed, and modified under those terms.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/err.h>
 #include <linux/mfd/syscon.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>

 #define MAX_SUPPLIES		16

 /*
  * The max voltage for 1.8V and 3.3V come from the Rockchip datasheet under
  * "Recommended Operating Conditions" for "Digital GPIO".   When the typical
  * is 3.3V the max is 3.6V.  When the typical is 1.8V the max is 1.98V.
  *
  * They are used like this:
  * - If the voltage on a rail is above the "1.8" voltage (1.98V) we'll tell the
  *   SoC we're at 3.3.
  * - If the voltage on a rail is above the "3.3" voltage (3.6V) we'll consider
  *   that to be an error.
  */
 #define MAX_VOLTAGE_1_8		1980000
 #define MAX_VOLTAGE_3_3		3600000

 #define RK3288_SOC_CON2			0x24c
 #define RK3288_SOC_CON2_FLASH0		BIT(7)
 #define RK3288_SOC_FLASH_SUPPLY_NUM	2

 #define RK3368_SOC_CON15		0x43c
 #define RK3368_SOC_CON15_FLASH0		BIT(14)
 #define RK3368_SOC_FLASH_SUPPLY_NUM	2

 struct rockchip_iodomain;

 /**
  * @supplies: voltage settings matching the register bits.
  */
 struct rockchip_iodomain_soc_data {
 	int grf_offset;
 	const char *supply_names[MAX_SUPPLIES];
 	void (*init)(struct rockchip_iodomain *iod);
 };

 struct rockchip_iodomain_supply {
 	struct rockchip_iodomain *iod;
 	struct regulator *reg;
 	struct notifier_block nb;
 	int idx;
 };

 struct rockchip_iodomain {
 	struct device *dev;
 	struct regmap *grf;
 	struct rockchip_iodomain_soc_data *soc_data;
 	struct rockchip_iodomain_supply supplies[MAX_SUPPLIES];
 };

 static int rockchip_iodomain_write(struct rockchip_iodomain_supply *supply,
 				   int uV)
 {
 	struct rockchip_iodomain *iod = supply->iod;
 	u32 val;
 	int ret;

 	/* set value bit */
 	val = (uV > MAX_VOLTAGE_1_8) ? 0 : 1;
 	val <<= supply->idx;

 	/* apply hiword-mask */
 	val |= (BIT(supply->idx) << 16);

 	ret = regmap_write(iod->grf, iod->soc_data->grf_offset, val);
 	if (ret)
 		dev_err(iod->dev, "Couldn't write to GRF\n");

 	return ret;
 }

 static int rockchip_iodomain_notify(struct notifier_block *nb,
 				    unsigned long event,
 				    void *data)
 {
 	struct rockchip_iodomain_supply *supply =
 			container_of(nb, struct rockchip_iodomain_supply, nb);
 	int uV;
 	int ret;

 	/*
 	 * According to Rockchip it's important to keep the SoC IO domain
 	 * higher than (or equal to) the external voltage.  That means we need
 	 * to change it before external voltage changes happen in the case
 	 * of an increase.
 	 *
 	 * Note that in the "pre" change we pick the max possible voltage that
 	 * the regulator might end up at (the client requests a range and we
 	 * don't know for certain the exact voltage).  Right now we rely on the
 	 * slop in MAX_VOLTAGE_1_8 and MAX_VOLTAGE_3_3 to save us if clients
 	 * request something like a max of 3.6V when they really want 3.3V.
 	 * We could attempt to come up with better rules if this fails.
 	 */
 	if (event & REGULATOR_EVENT_PRE_VOLTAGE_CHANGE) {
 		struct pre_voltage_change_data *pvc_data = data;

 		uV = max_t(unsigned long, pvc_data->old_uV, pvc_data->max_uV);
 	} else if (event & (REGULATOR_EVENT_VOLTAGE_CHANGE |
 			    REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE)) {
 		uV = (unsigned long)data;
 	} else {
 		return NOTIFY_OK;
 	}

 	dev_dbg(supply->iod->dev, "Setting to %d\n", uV);

 	if (uV > MAX_VOLTAGE_3_3) {
 		dev_err(supply->iod->dev, "Voltage too high: %d\n", uV);

 		if (event == REGULATOR_EVENT_PRE_VOLTAGE_CHANGE)
 			return NOTIFY_BAD;
 	}

 	ret = rockchip_iodomain_write(supply, uV);
 	if (ret && event == REGULATOR_EVENT_PRE_VOLTAGE_CHANGE)
 		return NOTIFY_BAD;

 	dev_info(supply->iod->dev, "Setting to %d done\n", uV);
 	return NOTIFY_OK;
 }

 static void rk3288_iodomain_init(struct rockchip_iodomain *iod)
 {
 	int ret;
 	u32 val;

 	/* if no flash supply we should leave things alone */
 	if (!iod->supplies[RK3288_SOC_FLASH_SUPPLY_NUM].reg)
 		return;

 	/*
 	 * set flash0 iodomain to also use this framework
 	 * instead of a special gpio.
 	 */
 	val = RK3288_SOC_CON2_FLASH0 | (RK3288_SOC_CON2_FLASH0 << 16);
 	ret = regmap_write(iod->grf, RK3288_SOC_CON2, val);
 	if (ret < 0)
 		dev_warn(iod->dev, "couldn't update flash0 ctrl\n");
 }

 static void rk3368_iodomain_init(struct rockchip_iodomain *iod)
 {
 	int ret;
 	u32 val;

 	/* if no flash supply we should leave things alone */
 	if (!iod->supplies[RK3368_SOC_FLASH_SUPPLY_NUM].reg)
 		return;

 	/*
 	 * set flash0 iodomain to also use this framework
 	 * instead of a special gpio.
 	 */
 	val = RK3368_SOC_CON15_FLASH0 | (RK3368_SOC_CON15_FLASH0 << 16);
 	ret = regmap_write(iod->grf, RK3368_SOC_CON15, val);
 	if (ret < 0)
 		dev_warn(iod->dev, "couldn't update flash0 ctrl\n");
 }

 /*
  * On the rk3188 the io-domains are handled by a shared register with the
  * lower 8 bits being still being continuing drive-strength settings.
  */
 static const struct rockchip_iodomain_soc_data soc_data_rk3188 = {
 	.grf_offset = 0x104,
 	.supply_names = {
 		NULL,
 		NULL,
 		NULL,
 		NULL,
 		NULL,
 		NULL,
 		NULL,
 		NULL,
 		"ap0",
 		"ap1",
 		"cif",
 		"flash",
 		"vccio0",
 		"vccio1",
 		"lcdc0",
 		"lcdc1",
 	},
 };

 static const struct rockchip_iodomain_soc_data soc_data_rk3288 = {
 	.grf_offset = 0x380,
 	.supply_names = {
 		"lcdc",		/* LCDC_VDD */
 		"dvp",		/* DVPIO_VDD */
 		"flash0",	/* FLASH0_VDD (emmc) */
 		"flash1",	/* FLASH1_VDD (sdio1) */
 		"wifi",		/* APIO3_VDD  (sdio0) */
 		"bb",		/* APIO5_VDD */
 		"audio",	/* APIO4_VDD */
 		"sdcard",	/* SDMMC0_VDD (sdmmc) */
 		"gpio30",	/* APIO1_VDD */
 		"gpio1830",	/* APIO2_VDD */
 	},
 	.init = rk3288_iodomain_init,
 };

 static const struct rockchip_iodomain_soc_data soc_data_rk3368 = {
 	.grf_offset = 0x900,
 	.supply_names = {
 		NULL,		/* reserved */
 		"dvp",		/* DVPIO_VDD */
 		"flash0",	/* FLASH0_VDD (emmc) */
 		"wifi",		/* APIO2_VDD (sdio0) */
 		NULL,
 		"audio",	/* APIO3_VDD */
 		"sdcard",	/* SDMMC0_VDD (sdmmc) */
 		"gpio30",	/* APIO1_VDD */
 		"gpio1830",	/* APIO4_VDD (gpujtag) */
 	},
 	.init = rk3368_iodomain_init,
 };

 static const struct rockchip_iodomain_soc_data soc_data_rk3368_pmu = {
 	.grf_offset = 0x100,
 	.supply_names = {
 		NULL,
 		NULL,
 		NULL,
 		NULL,
 		"pmu",	        /*PMU IO domain*/
 		"vop",	        /*LCDC IO domain*/
 	},
 };

 static const struct of_device_id rockchip_iodomain_match[] = {
 	{
 		.compatible = "rockchip,rk3188-io-voltage-domain",
 		.data = (void *)&soc_data_rk3188
 	},
 	{
 		.compatible = "rockchip,rk3288-io-voltage-domain",
 		.data = (void *)&soc_data_rk3288
 	},
 	{
 		.compatible = "rockchip,rk3368-io-voltage-domain",
 		.data = (void *)&soc_data_rk3368
 	},
 	{
 		.compatible = "rockchip,rk3368-pmu-io-voltage-domain",
 		.data = (void *)&soc_data_rk3368_pmu
 	},
 	{ /* sentinel */ },
 };

 static int rockchip_iodomain_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	const struct of_device_id *match;
 	struct rockchip_iodomain *iod;
 	int i, ret = 0;

 	if (!np)
 		return -ENODEV;

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

 	iod->dev = &pdev->dev;
 	platform_set_drvdata(pdev, iod);

 	match = of_match_node(rockchip_iodomain_match, np);
 	iod->soc_data = (struct rockchip_iodomain_soc_data *)match->data;

 	iod->grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
 	if (IS_ERR(iod->grf)) {
 		dev_err(&pdev->dev, "couldn't find grf regmap\n");
 		return PTR_ERR(iod->grf);
 	}

 	for (i = 0; i < MAX_SUPPLIES; i++) {
 		const char *supply_name = iod->soc_data->supply_names[i];
 		struct rockchip_iodomain_supply *supply = &iod->supplies[i];
 		struct regulator *reg;
 		int uV;

 		if (!supply_name)
 			continue;

 		reg = devm_regulator_get_optional(iod->dev, supply_name);
 		if (IS_ERR(reg)) {
 			ret = PTR_ERR(reg);

 			/* If a supply wasn't specified, that's OK */
 			if (ret == -ENODEV)
 				continue;
 			else if (ret != -EPROBE_DEFER)
 				dev_err(iod->dev, "couldn't get regulator %s\n",
 					supply_name);
 			goto unreg_notify;
 		}

 		/* set initial correct value */
 		uV = regulator_get_voltage(reg);

 		/* must be a regulator we can get the voltage of */
 		if (uV < 0) {
 			dev_err(iod->dev, "Can't determine voltage: %s\n",
 				supply_name);
 			goto unreg_notify;
 		}

 		if (uV > MAX_VOLTAGE_3_3) {
 			dev_crit(iod->dev,
 				 "%d uV is too high. May damage SoC!\n",
 				 uV);
 			ret = -EINVAL;
 			goto unreg_notify;
 		}

 		/* setup our supply */
 		supply->idx = i;
 		supply->iod = iod;
 		supply->reg = reg;
 		supply->nb.notifier_call = rockchip_iodomain_notify;

 		ret = rockchip_iodomain_write(supply, uV);
 		if (ret) {
 			supply->reg = NULL;
 			goto unreg_notify;
 		}

 		/* register regulator notifier */
 		ret = regulator_register_notifier(reg, &supply->nb);
 		if (ret) {
 			dev_err(&pdev->dev,
 				"regulator notifier request failed\n");
 			supply->reg = NULL;
 			goto unreg_notify;
 		}
 	}

 	if (iod->soc_data->init)
 		iod->soc_data->init(iod);

 	return 0;

 unreg_notify:
 	for (i = MAX_SUPPLIES - 1; i >= 0; i--) {
 		struct rockchip_iodomain_supply *io_supply = &iod->supplies[i];

 		if (io_supply->reg)
 			regulator_unregister_notifier(io_supply->reg,
 						      &io_supply->nb);
 	}

 	return ret;
 }

 static int rockchip_iodomain_remove(struct platform_device *pdev)
 {
 	struct rockchip_iodomain *iod = platform_get_drvdata(pdev);
 	int i;

 	for (i = MAX_SUPPLIES - 1; i >= 0; i--) {
 		struct rockchip_iodomain_supply *io_supply = &iod->supplies[i];

 		if (io_supply->reg)
 			regulator_unregister_notifier(io_supply->reg,
 						      &io_supply->nb);
 	}

 	return 0;
 }

 static struct platform_driver rockchip_iodomain_driver = {
 	.probe   = rockchip_iodomain_probe,
 	.remove  = rockchip_iodomain_remove,
 	.driver  = {
 		.name  = "rockchip-iodomain",
 		.of_match_table = rockchip_iodomain_match,
 	},
 };

 module_platform_driver(rockchip_iodomain_driver);

 MODULE_DESCRIPTION("Rockchip IO-domain driver");
 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 MODULE_AUTHOR("Doug Anderson <dianders@chromium.org>");
 MODULE_LICENSE("GPL v2");
	/*
	* Rockchip IO Voltage Domain driver
	*
	* Copyright 2014 MundoReader S.L.
	* Copyright 2014 Google, Inc.
	*
	* This software is licensed under the terms of the GNU General Public
	* License version 2, as published by the Free Software Foundation, and
	* may be copied, distributed, and modified under those terms.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/err.h>
	#include <linux/mfd/syscon.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/regmap.h>
	#include <linux/regulator/consumer.h>

	#define MAX_SUPPLIES 16

	/*
	* The max voltage for 1.8V and 3.3V come from the Rockchip datasheet under
	* "Recommended Operating Conditions" for "Digital GPIO". When the typical
	* is 3.3V the max is 3.6V. When the typical is 1.8V the max is 1.98V.
	*
	* They are used like this:
	* - If the voltage on a rail is above the "1.8" voltage (1.98V) we'll tell the
	* SoC we're at 3.3.
	* - If the voltage on a rail is above the "3.3" voltage (3.6V) we'll consider
	* that to be an error.
	*/
	#define MAX_VOLTAGE_1_8 1980000
	#define MAX_VOLTAGE_3_3 3600000

	#define RK3288_SOC_CON2 0x24c
	#define RK3288_SOC_CON2_FLASH0 BIT(7)
	#define RK3288_SOC_FLASH_SUPPLY_NUM 2

	#define RK3368_SOC_CON15 0x43c
	#define RK3368_SOC_CON15_FLASH0 BIT(14)
	#define RK3368_SOC_FLASH_SUPPLY_NUM 2

	struct rockchip_iodomain;

	/**
	* @supplies: voltage settings matching the register bits.
	*/
	struct rockchip_iodomain_soc_data {
	int grf_offset;
	const char *supply_names[MAX_SUPPLIES];
	void (init)(struct rockchip_iodomain iod);
	};

	struct rockchip_iodomain_supply {
	struct rockchip_iodomain *iod;
	struct regulator *reg;
	struct notifier_block nb;
	int idx;
	};

	struct rockchip_iodomain {
	struct device *dev;
	struct regmap *grf;
	struct rockchip_iodomain_soc_data *soc_data;
	struct rockchip_iodomain_supply supplies[MAX_SUPPLIES];
	};

	static int rockchip_iodomain_write(struct rockchip_iodomain_supply *supply,
	int uV)
	{
	struct rockchip_iodomain *iod = supply->iod;
	u32 val;
	int ret;

	/* set value bit */
	val = (uV > MAX_VOLTAGE_1_8) ? 0 : 1;
	val <<= supply->idx;

	/* apply hiword-mask */
	val \|= (BIT(supply->idx) << 16);

	ret = regmap_write(iod->grf, iod->soc_data->grf_offset, val);
	if (ret)
	dev_err(iod->dev, "Couldn't write to GRF\n");

	return ret;
	}

	static int rockchip_iodomain_notify(struct notifier_block *nb,
	unsigned long event,
	void *data)
	{
	struct rockchip_iodomain_supply *supply =
	container_of(nb, struct rockchip_iodomain_supply, nb);
	int uV;
	int ret;

	/*
	* According to Rockchip it's important to keep the SoC IO domain
	* higher than (or equal to) the external voltage. That means we need
	* to change it before external voltage changes happen in the case
	* of an increase.
	*
	* Note that in the "pre" change we pick the max possible voltage that
	* the regulator might end up at (the client requests a range and we
	* don't know for certain the exact voltage). Right now we rely on the
	* slop in MAX_VOLTAGE_1_8 and MAX_VOLTAGE_3_3 to save us if clients
	* request something like a max of 3.6V when they really want 3.3V.
	* We could attempt to come up with better rules if this fails.
	*/
	if (event & REGULATOR_EVENT_PRE_VOLTAGE_CHANGE) {
	struct pre_voltage_change_data *pvc_data = data;

	uV = max_t(unsigned long, pvc_data->old_uV, pvc_data->max_uV);
	} else if (event & (REGULATOR_EVENT_VOLTAGE_CHANGE \|
	REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE)) {
	uV = (unsigned long)data;
	} else {
	return NOTIFY_OK;
	}

	dev_dbg(supply->iod->dev, "Setting to %d\n", uV);

	if (uV > MAX_VOLTAGE_3_3) {
	dev_err(supply->iod->dev, "Voltage too high: %d\n", uV);

	if (event == REGULATOR_EVENT_PRE_VOLTAGE_CHANGE)
	return NOTIFY_BAD;
	}

	ret = rockchip_iodomain_write(supply, uV);
	if (ret && event == REGULATOR_EVENT_PRE_VOLTAGE_CHANGE)
	return NOTIFY_BAD;

	dev_info(supply->iod->dev, "Setting to %d done\n", uV);
	return NOTIFY_OK;
	}

	static void rk3288_iodomain_init(struct rockchip_iodomain *iod)
	{
	int ret;
	u32 val;

	/* if no flash supply we should leave things alone */
	if (!iod->supplies[RK3288_SOC_FLASH_SUPPLY_NUM].reg)
	return;

	/*
	* set flash0 iodomain to also use this framework
	* instead of a special gpio.
	*/
	val = RK3288_SOC_CON2_FLASH0 \| (RK3288_SOC_CON2_FLASH0 << 16);
	ret = regmap_write(iod->grf, RK3288_SOC_CON2, val);
	if (ret < 0)
	dev_warn(iod->dev, "couldn't update flash0 ctrl\n");
	}

	static void rk3368_iodomain_init(struct rockchip_iodomain *iod)
	{
	int ret;
	u32 val;

	/* if no flash supply we should leave things alone */
	if (!iod->supplies[RK3368_SOC_FLASH_SUPPLY_NUM].reg)
	return;

	/*
	* set flash0 iodomain to also use this framework
	* instead of a special gpio.
	*/
	val = RK3368_SOC_CON15_FLASH0 \| (RK3368_SOC_CON15_FLASH0 << 16);
	ret = regmap_write(iod->grf, RK3368_SOC_CON15, val);
	if (ret < 0)
	dev_warn(iod->dev, "couldn't update flash0 ctrl\n");
	}

	/*
	* On the rk3188 the io-domains are handled by a shared register with the
	* lower 8 bits being still being continuing drive-strength settings.
	*/
	static const struct rockchip_iodomain_soc_data soc_data_rk3188 = {
	.grf_offset = 0x104,
	.supply_names = {
	NULL,
	NULL,
	NULL,
	NULL,
	NULL,
	NULL,
	NULL,
	NULL,
	"ap0",
	"ap1",
	"cif",
	"flash",
	"vccio0",
	"vccio1",
	"lcdc0",
	"lcdc1",
	},
	};

	static const struct rockchip_iodomain_soc_data soc_data_rk3288 = {
	.grf_offset = 0x380,
	.supply_names = {
	"lcdc", /* LCDC_VDD */
	"dvp", /* DVPIO_VDD */
	"flash0", /* FLASH0_VDD (emmc) */
	"flash1", /* FLASH1_VDD (sdio1) */
	"wifi", /* APIO3_VDD (sdio0) */
	"bb", /* APIO5_VDD */
	"audio", /* APIO4_VDD */
	"sdcard", /* SDMMC0_VDD (sdmmc) */
	"gpio30", /* APIO1_VDD */
	"gpio1830", /* APIO2_VDD */
	},
	.init = rk3288_iodomain_init,
	};

	static const struct rockchip_iodomain_soc_data soc_data_rk3368 = {
	.grf_offset = 0x900,
	.supply_names = {
	NULL, /* reserved */
	"dvp", /* DVPIO_VDD */
	"flash0", /* FLASH0_VDD (emmc) */
	"wifi", /* APIO2_VDD (sdio0) */
	NULL,
	"audio", /* APIO3_VDD */
	"sdcard", /* SDMMC0_VDD (sdmmc) */
	"gpio30", /* APIO1_VDD */
	"gpio1830", /* APIO4_VDD (gpujtag) */
	},
	.init = rk3368_iodomain_init,
	};

	static const struct rockchip_iodomain_soc_data soc_data_rk3368_pmu = {
	.grf_offset = 0x100,
	.supply_names = {
	NULL,
	NULL,
	NULL,
	NULL,
	"pmu", /PMU IO domain/
	"vop", /LCDC IO domain/
	},
	};

	static const struct of_device_id rockchip_iodomain_match[] = {
	{
	.compatible = "rockchip,rk3188-io-voltage-domain",
	.data = (void *)&soc_data_rk3188
	},
	{
	.compatible = "rockchip,rk3288-io-voltage-domain",
	.data = (void *)&soc_data_rk3288
	},
	{
	.compatible = "rockchip,rk3368-io-voltage-domain",
	.data = (void *)&soc_data_rk3368
	},
	{
	.compatible = "rockchip,rk3368-pmu-io-voltage-domain",
	.data = (void *)&soc_data_rk3368_pmu
	},
	{ /* sentinel */ },
	};

	static int rockchip_iodomain_probe(struct platform_device *pdev)
	{
	struct device_node *np = pdev->dev.of_node;
	const struct of_device_id *match;
	struct rockchip_iodomain *iod;
	int i, ret = 0;

	if (!np)
	return -ENODEV;

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

	iod->dev = &pdev->dev;
	platform_set_drvdata(pdev, iod);

	match = of_match_node(rockchip_iodomain_match, np);
	iod->soc_data = (struct rockchip_iodomain_soc_data *)match->data;

	iod->grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
	if (IS_ERR(iod->grf)) {
	dev_err(&pdev->dev, "couldn't find grf regmap\n");
	return PTR_ERR(iod->grf);
	}

	for (i = 0; i < MAX_SUPPLIES; i++) {
	const char *supply_name = iod->soc_data->supply_names[i];
	struct rockchip_iodomain_supply *supply = &iod->supplies[i];
	struct regulator *reg;
	int uV;

	if (!supply_name)
	continue;

	reg = devm_regulator_get_optional(iod->dev, supply_name);
	if (IS_ERR(reg)) {
	ret = PTR_ERR(reg);

	/* If a supply wasn't specified, that's OK */
	if (ret == -ENODEV)
	continue;
	else if (ret != -EPROBE_DEFER)
	dev_err(iod->dev, "couldn't get regulator %s\n",
	supply_name);
	goto unreg_notify;
	}

	/* set initial correct value */
	uV = regulator_get_voltage(reg);

	/* must be a regulator we can get the voltage of */
	if (uV < 0) {
	dev_err(iod->dev, "Can't determine voltage: %s\n",
	supply_name);
	goto unreg_notify;
	}

	if (uV > MAX_VOLTAGE_3_3) {
	dev_crit(iod->dev,
	"%d uV is too high. May damage SoC!\n",
	uV);
	ret = -EINVAL;
	goto unreg_notify;
	}

	/* setup our supply */
	supply->idx = i;
	supply->iod = iod;
	supply->reg = reg;
	supply->nb.notifier_call = rockchip_iodomain_notify;

	ret = rockchip_iodomain_write(supply, uV);
	if (ret) {
	supply->reg = NULL;
	goto unreg_notify;
	}

	/* register regulator notifier */
	ret = regulator_register_notifier(reg, &supply->nb);
	if (ret) {
	dev_err(&pdev->dev,
	"regulator notifier request failed\n");
	supply->reg = NULL;
	goto unreg_notify;
	}
	}

	if (iod->soc_data->init)
	iod->soc_data->init(iod);

	return 0;

	unreg_notify:
	for (i = MAX_SUPPLIES - 1; i >= 0; i--) {
	struct rockchip_iodomain_supply *io_supply = &iod->supplies[i];

	if (io_supply->reg)
	regulator_unregister_notifier(io_supply->reg,
	&io_supply->nb);
	}

	return ret;
	}

	static int rockchip_iodomain_remove(struct platform_device *pdev)
	{
	struct rockchip_iodomain *iod = platform_get_drvdata(pdev);
	int i;

	for (i = MAX_SUPPLIES - 1; i >= 0; i--) {
	struct rockchip_iodomain_supply *io_supply = &iod->supplies[i];

	if (io_supply->reg)
	regulator_unregister_notifier(io_supply->reg,
	&io_supply->nb);
	}

	return 0;
	}

	static struct platform_driver rockchip_iodomain_driver = {
	.probe = rockchip_iodomain_probe,
	.remove = rockchip_iodomain_remove,
	.driver = {
	.name = "rockchip-iodomain",
	.of_match_table = rockchip_iodomain_match,
	},
	};

	module_platform_driver(rockchip_iodomain_driver);

	MODULE_DESCRIPTION("Rockchip IO-domain driver");
	MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
	MODULE_AUTHOR("Doug Anderson <dianders@chromium.org>");
	MODULE_LICENSE("GPL v2");