drivers/misc/smsc_hub.c - kernel/msm.git - Git at Google

 /* Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
  * only version 2 as published by the Free Software Foundation.
  *
  * 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/platform_device.h>
 #include <linux/err.h>
 #include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 #include <linux/i2c.h>
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
 #include <linux/of_device.h>
 #include <linux/clk.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/smsc3503.h>
 #include <linux/module.h>
 #include <mach/msm_xo.h>

 #define SMSC3503_I2C_ADDR 0x08
 #define SMSC_GSBI_I2C_BUS_ID 10
 static const unsigned short normal_i2c[] = {
 SMSC3503_I2C_ADDR, I2C_CLIENT_END };

 struct hsic_hub {
 	struct device *dev;
 	struct smsc_hub_platform_data *pdata;
 	struct i2c_client *client;
 	struct msm_xo_voter *xo_handle;
 	struct clk		*ref_clk;
 	struct regulator	*hsic_hub_reg;
 	struct regulator	*int_pad_reg, *hub_vbus_reg;
 };
 static struct hsic_hub *smsc_hub;
 static struct platform_driver smsc_hub_driver;

 /* APIs for setting/clearing bits and for reading/writing values */
 static inline int hsic_hub_get_u8(struct i2c_client *client, u8 reg)
 {
 	int ret;

 	ret = i2c_smbus_read_byte_data(client, reg);
 	if (ret < 0)
 		pr_err("%s:i2c_read8 failed\n", __func__);
 	return ret;
 }

 static inline int hsic_hub_get_u16(struct i2c_client *client, u8 reg)
 {
 	int ret;

 	ret = i2c_smbus_read_word_data(client, reg);
 	if (ret < 0)
 		pr_err("%s:i2c_read16 failed\n", __func__);
 	return ret;
 }

 static inline int hsic_hub_write_word_data(struct i2c_client *client, u8 reg,
 						u16 value)
 {
 	int ret;

 	ret = i2c_smbus_write_word_data(client, reg, value);
 	if (ret)
 		pr_err("%s:i2c_write16 failed\n", __func__);
 	return ret;
 }

 static inline int hsic_hub_write_byte_data(struct i2c_client *client, u8 reg,
 						u8 value)
 {
 	int ret;

 	ret = i2c_smbus_write_byte_data(client, reg, value);
 	if (ret)
 		pr_err("%s:i2c_write_byte_data failed\n", __func__);
 	return ret;
 }

 static inline int hsic_hub_set_bits(struct i2c_client *client, u8 reg,
 					u8 value)
 {
 	int ret;

 	ret = i2c_smbus_read_byte_data(client, reg);
 	if (ret < 0) {
 		pr_err("%s:i2c_read_byte_data failed\n", __func__);
 		return ret;
 	}
 	return i2c_smbus_write_byte_data(client, reg, (ret | value));
 }

 static inline int hsic_hub_clear_bits(struct i2c_client *client, u8 reg,
 					u8 value)
 {
 	int ret;

 	ret = i2c_smbus_read_byte_data(client, reg);
 	if (ret < 0) {
 		pr_err("%s:i2c_read_byte_data failed\n", __func__);
 		return ret;
 	}
 	return i2c_smbus_write_byte_data(client, reg, (ret & ~value));
 }

 static int i2c_hsic_hub_probe(struct i2c_client *client,
 				const struct i2c_device_id *id)
 {
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 				     I2C_FUNC_SMBUS_WORD_DATA))
 		return -EIO;

 	/* CONFIG_N bit in SP_ILOCK register has to be set before changing
 	 * other registers to change default configuration of hsic hub.
 	 */
 	hsic_hub_set_bits(client, SMSC3503_SP_ILOCK, CONFIG_N);

 	/* Can change default configuartion like VID,PID, strings etc
 	 * by writing new values to hsic hub registers.
 	 */
 	hsic_hub_write_word_data(client, SMSC3503_VENDORID, 0x05C6);

 	/* CONFIG_N bit in SP_ILOCK register has to be cleared for new
 	 * values in registers to be effective after writing to
 	 * other registers.
 	 */
 	hsic_hub_clear_bits(client, SMSC3503_SP_ILOCK, CONFIG_N);

 	return 0;
 }

 static int i2c_hsic_hub_remove(struct i2c_client *client)
 {
 	return 0;
 }

 static const struct i2c_device_id hsic_hub_id[] = {
 	{"i2c_hsic_hub", 0},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, hsichub_id);

 static struct i2c_driver hsic_hub_driver = {
 	.driver = {
 		.name = "i2c_hsic_hub",
 	},
 	.probe    = i2c_hsic_hub_probe,
 	.remove   = i2c_hsic_hub_remove,
 	.id_table = hsic_hub_id,
 };

 static int msm_hsic_hub_init_clock(struct hsic_hub *hub, int init)
 {
 	int ret;

 	if (!init) {
 		if (!IS_ERR(hub->ref_clk))
 			clk_disable_unprepare(hub->ref_clk);
 		else
 			msm_xo_put(smsc_hub->xo_handle);

 		return 0;
 	}

 	hub->ref_clk = devm_clk_get(hub->dev, "ref_clk");
 	if (IS_ERR(hub->ref_clk)) {
 		dev_dbg(hub->dev, "failed to get ref_clk\n");

 		/* In the absence of dedicated ref_clk, xo clocks the HUB */
 		smsc_hub->xo_handle = msm_xo_get(MSM_XO_TCXO_D1, "hsic_hub");
 		if (IS_ERR(smsc_hub->xo_handle)) {
 			dev_err(hub->dev, "not able to get the handle\n"
 						 "for TCXO D1 buffer\n");
 			return PTR_ERR(smsc_hub->xo_handle);
 		}

 		ret = msm_xo_mode_vote(smsc_hub->xo_handle, MSM_XO_MODE_ON);
 		if (ret) {
 			dev_err(hub->dev, "failed to vote for TCXO\n"
 				"D1 buffer\n");
 			msm_xo_put(smsc_hub->xo_handle);
 			return ret;
 		}
 	} else {
 		ret = clk_prepare_enable(hub->ref_clk);
 		if (ret)
 			dev_err(hub->dev, "clk_enable failed for ref_clk\n");
 	}

 	return ret;
 }
 #define HSIC_HUB_INT_VOL_MIN	1800000 /* uV */
 #define HSIC_HUB_INT_VOL_MAX	2950000 /* uV */
 static int msm_hsic_hub_init_gpio(struct hsic_hub *hub, int init)
 {
 	int ret;
 	struct smsc_hub_platform_data *pdata = hub->pdata;

 	if (!init) {
 		if (!IS_ERR(smsc_hub->int_pad_reg)) {
 			regulator_disable(smsc_hub->int_pad_reg);
 			regulator_set_voltage(smsc_hub->int_pad_reg, 0,
 						HSIC_HUB_INT_VOL_MAX);
 		}
 		return 0;
 	}

 	ret = devm_gpio_request(hub->dev, pdata->hub_reset, "HSIC_HUB_RESET");
 	if (ret < 0) {
 		dev_err(hub->dev, "gpio request failed for GPIO%d\n",
 							pdata->hub_reset);
 		return ret;
 	}

 	if (pdata->refclk_gpio) {
 		ret = devm_gpio_request(hub->dev, pdata->refclk_gpio,
 							 "HSIC_HUB_CLK");
 		if (ret < 0)
 			dev_err(hub->dev, "gpio request failed (CLK GPIO)\n");
 	}

 	if (pdata->int_gpio) {
 		ret = devm_gpio_request(hub->dev, pdata->int_gpio,
 							 "HSIC_HUB_INT");
 		if (ret < 0) {
 			dev_err(hub->dev, "gpio request failed (INT GPIO)\n");
 			return ret;
 		}

 		/* Enable LDO if required for external pull-up */
 		smsc_hub->int_pad_reg = devm_regulator_get(hub->dev, "hub_int");
 		if (IS_ERR(smsc_hub->int_pad_reg)) {
 			dev_dbg(hub->dev, "unable to get ext hub_int reg\n");
 		} else {
 			ret = regulator_set_voltage(smsc_hub->int_pad_reg,
 						HSIC_HUB_INT_VOL_MIN,
 						HSIC_HUB_INT_VOL_MAX);
 			if (ret) {
 				dev_err(hub->dev, "unable to set the voltage\n"
 						" for hsic hub int reg\n");
 				return ret;
 			}
 			ret = regulator_enable(smsc_hub->int_pad_reg);
 			if (ret) {
 				dev_err(hub->dev, "unable to enable int reg\n");
 				regulator_set_voltage(smsc_hub->int_pad_reg, 0,
 							HSIC_HUB_INT_VOL_MAX);
 				return ret;
 			}
 		}
 	}

 	return 0;
 }

 #define HSIC_HUB_VDD_VOL_MIN	1650000 /* uV */
 #define HSIC_HUB_VDD_VOL_MAX	1950000 /* uV */
 #define HSIC_HUB_VDD_LOAD	36000	/* uA */
 static int msm_hsic_hub_init_vdd(struct hsic_hub *hub, int init)
 {
 	int ret;

 	if (!init) {
 		if (!IS_ERR(smsc_hub->hsic_hub_reg)) {
 			regulator_disable(smsc_hub->hsic_hub_reg);
 			regulator_set_optimum_mode(smsc_hub->hsic_hub_reg, 0);
 			regulator_set_voltage(smsc_hub->hsic_hub_reg, 0,
 							HSIC_HUB_VDD_VOL_MAX);
 		}
 		return 0;
 	}

 	smsc_hub->hsic_hub_reg = devm_regulator_get(hub->dev, "EXT_HUB_VDDIO");
 	if (IS_ERR(smsc_hub->hsic_hub_reg)) {
 		dev_dbg(hub->dev, "unable to get ext hub vddcx\n");
 	} else {
 		ret = regulator_set_voltage(smsc_hub->hsic_hub_reg,
 				HSIC_HUB_VDD_VOL_MIN,
 				HSIC_HUB_VDD_VOL_MAX);
 		if (ret) {
 			dev_err(hub->dev, "unable to set the voltage\n"
 						"for hsic hub reg\n");
 			return ret;
 		}

 		ret = regulator_set_optimum_mode(smsc_hub->hsic_hub_reg,
 					HSIC_HUB_VDD_LOAD);
 		if (ret < 0) {
 			dev_err(hub->dev, "Unable to set mode of VDDCX\n");
 			goto reg_optimum_mode_fail;
 		}

 		ret = regulator_enable(smsc_hub->hsic_hub_reg);
 		if (ret) {
 			dev_err(hub->dev, "unable to enable ext hub vddcx\n");
 			goto reg_enable_fail;
 		}
 	}

 	return 0;

 reg_enable_fail:
 	regulator_set_optimum_mode(smsc_hub->hsic_hub_reg, 0);
 reg_optimum_mode_fail:
 	regulator_set_voltage(smsc_hub->hsic_hub_reg, 0,
 				HSIC_HUB_VDD_VOL_MAX);

 	return ret;
 }
 struct smsc_hub_platform_data *msm_hub_dt_to_pdata(
 				struct platform_device *pdev)
 {
 	struct device_node *node = pdev->dev.of_node;
 	struct smsc_hub_platform_data *pdata;

 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata) {
 		dev_err(&pdev->dev, "unable to allocate platform data\n");
 		return ERR_PTR(-ENOMEM);
 	}

 	pdata->hub_reset = of_get_named_gpio(node, "smsc,reset-gpio", 0);
 	if (pdata->hub_reset < 0)
 		return ERR_PTR(pdata->hub_reset);

 	pdata->refclk_gpio = of_get_named_gpio(node, "smsc,refclk-gpio", 0);
 	if (pdata->refclk_gpio < 0)
 		pdata->refclk_gpio = 0;

 	pdata->int_gpio = of_get_named_gpio(node, "smsc,int-gpio", 0);
 	if (pdata->int_gpio < 0)
 		pdata->int_gpio = 0;

 	return pdata;
 }

 static int __devinit smsc_hub_probe(struct platform_device *pdev)
 {
 	int ret = 0;
 	const struct smsc_hub_platform_data *pdata;
 	struct device_node *node = pdev->dev.of_node;
 	struct i2c_adapter *i2c_adap;
 	struct i2c_board_info i2c_info;

 	if (pdev->dev.of_node) {
 		dev_dbg(&pdev->dev, "device tree enabled\n");
 		pdev->dev.platform_data = msm_hub_dt_to_pdata(pdev);
 		if (IS_ERR(pdev->dev.platform_data))
 			return PTR_ERR(pdev->dev.platform_data);

 		dev_set_name(&pdev->dev, smsc_hub_driver.driver.name);
 	}

 	if (!pdev->dev.platform_data) {
 		dev_err(&pdev->dev, "No platform data\n");
 		return -ENODEV;
 	}

 	pdata = pdev->dev.platform_data;
 	if (!pdata->hub_reset)
 		return -EINVAL;

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

 	smsc_hub->dev = &pdev->dev;
 	smsc_hub->pdata = pdev->dev.platform_data;

 	smsc_hub->hub_vbus_reg = devm_regulator_get(&pdev->dev, "hub_vbus");
 	ret = PTR_ERR(smsc_hub->hub_vbus_reg);
 	if (ret == -EPROBE_DEFER) {
 		dev_dbg(&pdev->dev, "failed to get hub_vbus\n");
 		return ret;
 	}

 	ret = msm_hsic_hub_init_vdd(smsc_hub, 1);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to init hub VDD\n");
 		return ret;
 	}
 	ret = msm_hsic_hub_init_clock(smsc_hub, 1);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to init hub clock\n");
 		goto uninit_vdd;
 	}
 	ret = msm_hsic_hub_init_gpio(smsc_hub, 1);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to init hub gpios\n");
 		goto uninit_clock;
 	}

 	gpio_direction_output(pdata->hub_reset, 0);
 	/* Hub reset should be asserted for minimum 2microsec
 	 * before deasserting.
 	 */
 	udelay(5);
 	gpio_direction_output(pdata->hub_reset, 1);

 	ret = of_platform_populate(node, NULL, NULL, &pdev->dev);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to add child node, ret=%d\n", ret);
 		goto uninit_gpio;
 	}

 	if (!IS_ERR(smsc_hub->hub_vbus_reg)) {
 		ret = regulator_enable(smsc_hub->hub_vbus_reg);
 		if (ret) {
 			dev_err(&pdev->dev, "unable to enable hub_vbus\n");
 			goto uninit_gpio;
 		}
 	}

 	ret = i2c_add_driver(&hsic_hub_driver);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to add I2C hsic_hub_driver\n");
 		goto i2c_add_fail;
 	}
 	usleep_range(10000, 12000);
 	i2c_adap = i2c_get_adapter(SMSC_GSBI_I2C_BUS_ID);

 	if (!i2c_adap) {
 		dev_err(&pdev->dev, "failed to get i2c adapter\n");
 		i2c_del_driver(&hsic_hub_driver);
 		goto i2c_add_fail;
 	}

 	memset(&i2c_info, 0, sizeof(struct i2c_board_info));
 	strlcpy(i2c_info.type, "i2c_hsic_hub", I2C_NAME_SIZE);

 	smsc_hub->client = i2c_new_probed_device(i2c_adap, &i2c_info,
 						   normal_i2c, NULL);
 	i2c_put_adapter(i2c_adap);
 	if (!smsc_hub->client)
 		dev_err(&pdev->dev, "failed to connect to smsc_hub"
 			 "through I2C\n");

 i2c_add_fail:
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);

 	return 0;

 uninit_gpio:
 	msm_hsic_hub_init_gpio(smsc_hub, 0);
 uninit_clock:
 	msm_hsic_hub_init_clock(smsc_hub, 0);
 uninit_vdd:
 	msm_hsic_hub_init_vdd(smsc_hub, 0);

 	return ret;
 }

 static int smsc_hub_remove(struct platform_device *pdev)
 {
 	const struct smsc_hub_platform_data *pdata;

 	pdata = pdev->dev.platform_data;
 	if (smsc_hub->client) {
 		i2c_unregister_device(smsc_hub->client);
 		smsc_hub->client = NULL;
 		i2c_del_driver(&hsic_hub_driver);
 	}
 	pm_runtime_disable(&pdev->dev);

 	if (!IS_ERR(smsc_hub->hub_vbus_reg))
 		regulator_disable(smsc_hub->hub_vbus_reg);
 	msm_hsic_hub_init_gpio(smsc_hub, 0);
 	msm_hsic_hub_init_clock(smsc_hub, 0);
 	msm_hsic_hub_init_vdd(smsc_hub, 0);

 	return 0;
 }

 #ifdef CONFIG_PM_RUNTIME
 static int msm_smsc_runtime_idle(struct device *dev)
 {
 	dev_dbg(dev, "SMSC HUB runtime idle\n");

 	return 0;
 }

 static int smsc_hub_lpm_enter(struct device *dev)
 {
 	int ret = 0;

 	if (smsc_hub->xo_handle) {
 		ret = msm_xo_mode_vote(smsc_hub->xo_handle, MSM_XO_MODE_OFF);
 		if (ret) {
 			pr_err("%s: failed to devote for TCXO\n"
 				"D1 buffer%d\n", __func__, ret);
 		}
 	}
 	return ret;
 }

 static int smsc_hub_lpm_exit(struct device *dev)
 {
 	int ret = 0;

 	if (smsc_hub->xo_handle) {
 		ret = msm_xo_mode_vote(smsc_hub->xo_handle, MSM_XO_MODE_ON);
 		if (ret) {
 			pr_err("%s: failed to vote for TCXO\n"
 				"D1 buffer%d\n", __func__, ret);
 		}
 	}
 	return ret;
 }
 #endif

 #ifdef CONFIG_PM
 static const struct dev_pm_ops smsc_hub_dev_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(smsc_hub_lpm_enter, smsc_hub_lpm_exit)
 	SET_RUNTIME_PM_OPS(smsc_hub_lpm_enter, smsc_hub_lpm_exit,
 				msm_smsc_runtime_idle)
 };
 #endif

 static const struct of_device_id hsic_hub_dt_match[] = {
 	{ .compatible = "qcom,hsic-smsc-hub",
 	},
 	{}
 };
 MODULE_DEVICE_TABLE(of, hsic_hub_dt_match);

 static struct platform_driver smsc_hub_driver = {
 	.driver = {
 		.name = "msm_smsc_hub",
 		.owner = THIS_MODULE,
 #ifdef CONFIG_PM
 		.pm = &smsc_hub_dev_pm_ops,
 #endif
 		.of_match_table = hsic_hub_dt_match,
 	},
 	.probe = smsc_hub_probe,
 	.remove = smsc_hub_remove,
 };

 static int __init smsc_hub_init(void)
 {
 	return platform_driver_register(&smsc_hub_driver);
 }

 static void __exit smsc_hub_exit(void)
 {
 	platform_driver_unregister(&smsc_hub_driver);
 }
 subsys_initcall(smsc_hub_init);
 module_exit(smsc_hub_exit);

 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("SMSC HSIC HUB driver");
	/* Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 and
	* only version 2 as published by the Free Software Foundation.
	*
	* 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/platform_device.h>
	#include <linux/err.h>
	#include <linux/pm_runtime.h>
	#include <linux/regulator/consumer.h>
	#include <linux/i2c.h>
	#include <linux/gpio.h>
	#include <linux/of_gpio.h>
	#include <linux/of_device.h>
	#include <linux/clk.h>
	#include <linux/slab.h>
	#include <linux/delay.h>
	#include <linux/smsc3503.h>
	#include <linux/module.h>
	#include <mach/msm_xo.h>

	#define SMSC3503_I2C_ADDR 0x08
	#define SMSC_GSBI_I2C_BUS_ID 10
	static const unsigned short normal_i2c[] = {
	SMSC3503_I2C_ADDR, I2C_CLIENT_END };

	struct hsic_hub {
	struct device *dev;
	struct smsc_hub_platform_data *pdata;
	struct i2c_client *client;
	struct msm_xo_voter *xo_handle;
	struct clk *ref_clk;
	struct regulator *hsic_hub_reg;
	struct regulator int_pad_reg, hub_vbus_reg;
	};
	static struct hsic_hub *smsc_hub;
	static struct platform_driver smsc_hub_driver;

	/* APIs for setting/clearing bits and for reading/writing values */
	static inline int hsic_hub_get_u8(struct i2c_client *client, u8 reg)
	{
	int ret;

	ret = i2c_smbus_read_byte_data(client, reg);
	if (ret < 0)
	pr_err("%s:i2c_read8 failed\n", __func__);
	return ret;
	}

	static inline int hsic_hub_get_u16(struct i2c_client *client, u8 reg)
	{
	int ret;

	ret = i2c_smbus_read_word_data(client, reg);
	if (ret < 0)
	pr_err("%s:i2c_read16 failed\n", __func__);
	return ret;
	}

	static inline int hsic_hub_write_word_data(struct i2c_client *client, u8 reg,
	u16 value)
	{
	int ret;

	ret = i2c_smbus_write_word_data(client, reg, value);
	if (ret)
	pr_err("%s:i2c_write16 failed\n", __func__);
	return ret;
	}

	static inline int hsic_hub_write_byte_data(struct i2c_client *client, u8 reg,
	u8 value)
	{
	int ret;

	ret = i2c_smbus_write_byte_data(client, reg, value);
	if (ret)
	pr_err("%s:i2c_write_byte_data failed\n", __func__);
	return ret;
	}

	static inline int hsic_hub_set_bits(struct i2c_client *client, u8 reg,
	u8 value)
	{
	int ret;

	ret = i2c_smbus_read_byte_data(client, reg);
	if (ret < 0) {
	pr_err("%s:i2c_read_byte_data failed\n", __func__);
	return ret;
	}
	return i2c_smbus_write_byte_data(client, reg, (ret \| value));
	}

	static inline int hsic_hub_clear_bits(struct i2c_client *client, u8 reg,
	u8 value)
	{
	int ret;

	ret = i2c_smbus_read_byte_data(client, reg);
	if (ret < 0) {
	pr_err("%s:i2c_read_byte_data failed\n", __func__);
	return ret;
	}
	return i2c_smbus_write_byte_data(client, reg, (ret & ~value));
	}

	static int i2c_hsic_hub_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA \|
	I2C_FUNC_SMBUS_WORD_DATA))
	return -EIO;

	/* CONFIG_N bit in SP_ILOCK register has to be set before changing
	* other registers to change default configuration of hsic hub.
	*/
	hsic_hub_set_bits(client, SMSC3503_SP_ILOCK, CONFIG_N);

	/* Can change default configuartion like VID,PID, strings etc
	* by writing new values to hsic hub registers.
	*/
	hsic_hub_write_word_data(client, SMSC3503_VENDORID, 0x05C6);

	/* CONFIG_N bit in SP_ILOCK register has to be cleared for new
	* values in registers to be effective after writing to
	* other registers.
	*/
	hsic_hub_clear_bits(client, SMSC3503_SP_ILOCK, CONFIG_N);

	return 0;
	}

	static int i2c_hsic_hub_remove(struct i2c_client *client)
	{
	return 0;
	}

	static const struct i2c_device_id hsic_hub_id[] = {
	{"i2c_hsic_hub", 0},
	{}
	};
	MODULE_DEVICE_TABLE(i2c, hsichub_id);

	static struct i2c_driver hsic_hub_driver = {
	.driver = {
	.name = "i2c_hsic_hub",
	},
	.probe = i2c_hsic_hub_probe,
	.remove = i2c_hsic_hub_remove,
	.id_table = hsic_hub_id,
	};

	static int msm_hsic_hub_init_clock(struct hsic_hub *hub, int init)
	{
	int ret;

	if (!init) {
	if (!IS_ERR(hub->ref_clk))
	clk_disable_unprepare(hub->ref_clk);
	else
	msm_xo_put(smsc_hub->xo_handle);

	return 0;
	}

	hub->ref_clk = devm_clk_get(hub->dev, "ref_clk");
	if (IS_ERR(hub->ref_clk)) {
	dev_dbg(hub->dev, "failed to get ref_clk\n");

	/* In the absence of dedicated ref_clk, xo clocks the HUB */
	smsc_hub->xo_handle = msm_xo_get(MSM_XO_TCXO_D1, "hsic_hub");
	if (IS_ERR(smsc_hub->xo_handle)) {
	dev_err(hub->dev, "not able to get the handle\n"
	"for TCXO D1 buffer\n");
	return PTR_ERR(smsc_hub->xo_handle);
	}

	ret = msm_xo_mode_vote(smsc_hub->xo_handle, MSM_XO_MODE_ON);
	if (ret) {
	dev_err(hub->dev, "failed to vote for TCXO\n"
	"D1 buffer\n");
	msm_xo_put(smsc_hub->xo_handle);
	return ret;
	}
	} else {
	ret = clk_prepare_enable(hub->ref_clk);
	if (ret)
	dev_err(hub->dev, "clk_enable failed for ref_clk\n");
	}

	return ret;
	}
	#define HSIC_HUB_INT_VOL_MIN 1800000 /* uV */
	#define HSIC_HUB_INT_VOL_MAX 2950000 /* uV */
	static int msm_hsic_hub_init_gpio(struct hsic_hub *hub, int init)
	{
	int ret;
	struct smsc_hub_platform_data *pdata = hub->pdata;

	if (!init) {
	if (!IS_ERR(smsc_hub->int_pad_reg)) {
	regulator_disable(smsc_hub->int_pad_reg);
	regulator_set_voltage(smsc_hub->int_pad_reg, 0,
	HSIC_HUB_INT_VOL_MAX);
	}
	return 0;
	}

	ret = devm_gpio_request(hub->dev, pdata->hub_reset, "HSIC_HUB_RESET");
	if (ret < 0) {
	dev_err(hub->dev, "gpio request failed for GPIO%d\n",
	pdata->hub_reset);
	return ret;
	}

	if (pdata->refclk_gpio) {
	ret = devm_gpio_request(hub->dev, pdata->refclk_gpio,
	"HSIC_HUB_CLK");
	if (ret < 0)
	dev_err(hub->dev, "gpio request failed (CLK GPIO)\n");
	}

	if (pdata->int_gpio) {
	ret = devm_gpio_request(hub->dev, pdata->int_gpio,
	"HSIC_HUB_INT");
	if (ret < 0) {
	dev_err(hub->dev, "gpio request failed (INT GPIO)\n");
	return ret;
	}

	/* Enable LDO if required for external pull-up */
	smsc_hub->int_pad_reg = devm_regulator_get(hub->dev, "hub_int");
	if (IS_ERR(smsc_hub->int_pad_reg)) {
	dev_dbg(hub->dev, "unable to get ext hub_int reg\n");
	} else {
	ret = regulator_set_voltage(smsc_hub->int_pad_reg,
	HSIC_HUB_INT_VOL_MIN,
	HSIC_HUB_INT_VOL_MAX);
	if (ret) {
	dev_err(hub->dev, "unable to set the voltage\n"
	" for hsic hub int reg\n");
	return ret;
	}
	ret = regulator_enable(smsc_hub->int_pad_reg);
	if (ret) {
	dev_err(hub->dev, "unable to enable int reg\n");
	regulator_set_voltage(smsc_hub->int_pad_reg, 0,
	HSIC_HUB_INT_VOL_MAX);
	return ret;
	}
	}
	}

	return 0;
	}

	#define HSIC_HUB_VDD_VOL_MIN 1650000 /* uV */
	#define HSIC_HUB_VDD_VOL_MAX 1950000 /* uV */
	#define HSIC_HUB_VDD_LOAD 36000 /* uA */
	static int msm_hsic_hub_init_vdd(struct hsic_hub *hub, int init)
	{
	int ret;

	if (!init) {
	if (!IS_ERR(smsc_hub->hsic_hub_reg)) {
	regulator_disable(smsc_hub->hsic_hub_reg);
	regulator_set_optimum_mode(smsc_hub->hsic_hub_reg, 0);
	regulator_set_voltage(smsc_hub->hsic_hub_reg, 0,
	HSIC_HUB_VDD_VOL_MAX);
	}
	return 0;
	}

	smsc_hub->hsic_hub_reg = devm_regulator_get(hub->dev, "EXT_HUB_VDDIO");
	if (IS_ERR(smsc_hub->hsic_hub_reg)) {
	dev_dbg(hub->dev, "unable to get ext hub vddcx\n");
	} else {
	ret = regulator_set_voltage(smsc_hub->hsic_hub_reg,
	HSIC_HUB_VDD_VOL_MIN,
	HSIC_HUB_VDD_VOL_MAX);
	if (ret) {
	dev_err(hub->dev, "unable to set the voltage\n"
	"for hsic hub reg\n");
	return ret;
	}

	ret = regulator_set_optimum_mode(smsc_hub->hsic_hub_reg,
	HSIC_HUB_VDD_LOAD);
	if (ret < 0) {
	dev_err(hub->dev, "Unable to set mode of VDDCX\n");
	goto reg_optimum_mode_fail;
	}

	ret = regulator_enable(smsc_hub->hsic_hub_reg);
	if (ret) {
	dev_err(hub->dev, "unable to enable ext hub vddcx\n");
	goto reg_enable_fail;
	}
	}

	return 0;

	reg_enable_fail:
	regulator_set_optimum_mode(smsc_hub->hsic_hub_reg, 0);
	reg_optimum_mode_fail:
	regulator_set_voltage(smsc_hub->hsic_hub_reg, 0,
	HSIC_HUB_VDD_VOL_MAX);

	return ret;
	}
	struct smsc_hub_platform_data *msm_hub_dt_to_pdata(
	struct platform_device *pdev)
	{
	struct device_node *node = pdev->dev.of_node;
	struct smsc_hub_platform_data *pdata;

	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
	if (!pdata) {
	dev_err(&pdev->dev, "unable to allocate platform data\n");
	return ERR_PTR(-ENOMEM);
	}

	pdata->hub_reset = of_get_named_gpio(node, "smsc,reset-gpio", 0);
	if (pdata->hub_reset < 0)
	return ERR_PTR(pdata->hub_reset);

	pdata->refclk_gpio = of_get_named_gpio(node, "smsc,refclk-gpio", 0);
	if (pdata->refclk_gpio < 0)
	pdata->refclk_gpio = 0;

	pdata->int_gpio = of_get_named_gpio(node, "smsc,int-gpio", 0);
	if (pdata->int_gpio < 0)
	pdata->int_gpio = 0;

	return pdata;
	}

	static int __devinit smsc_hub_probe(struct platform_device *pdev)
	{
	int ret = 0;
	const struct smsc_hub_platform_data *pdata;
	struct device_node *node = pdev->dev.of_node;
	struct i2c_adapter *i2c_adap;
	struct i2c_board_info i2c_info;

	if (pdev->dev.of_node) {
	dev_dbg(&pdev->dev, "device tree enabled\n");
	pdev->dev.platform_data = msm_hub_dt_to_pdata(pdev);
	if (IS_ERR(pdev->dev.platform_data))
	return PTR_ERR(pdev->dev.platform_data);

	dev_set_name(&pdev->dev, smsc_hub_driver.driver.name);
	}

	if (!pdev->dev.platform_data) {
	dev_err(&pdev->dev, "No platform data\n");
	return -ENODEV;
	}

	pdata = pdev->dev.platform_data;
	if (!pdata->hub_reset)
	return -EINVAL;

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

	smsc_hub->dev = &pdev->dev;
	smsc_hub->pdata = pdev->dev.platform_data;

	smsc_hub->hub_vbus_reg = devm_regulator_get(&pdev->dev, "hub_vbus");
	ret = PTR_ERR(smsc_hub->hub_vbus_reg);
	if (ret == -EPROBE_DEFER) {
	dev_dbg(&pdev->dev, "failed to get hub_vbus\n");
	return ret;
	}

	ret = msm_hsic_hub_init_vdd(smsc_hub, 1);
	if (ret) {
	dev_err(&pdev->dev, "failed to init hub VDD\n");
	return ret;
	}
	ret = msm_hsic_hub_init_clock(smsc_hub, 1);
	if (ret) {
	dev_err(&pdev->dev, "failed to init hub clock\n");
	goto uninit_vdd;
	}
	ret = msm_hsic_hub_init_gpio(smsc_hub, 1);
	if (ret) {
	dev_err(&pdev->dev, "failed to init hub gpios\n");
	goto uninit_clock;
	}

	gpio_direction_output(pdata->hub_reset, 0);
	/* Hub reset should be asserted for minimum 2microsec
	* before deasserting.
	*/
	udelay(5);
	gpio_direction_output(pdata->hub_reset, 1);

	ret = of_platform_populate(node, NULL, NULL, &pdev->dev);
	if (ret) {
	dev_err(&pdev->dev, "failed to add child node, ret=%d\n", ret);
	goto uninit_gpio;
	}

	if (!IS_ERR(smsc_hub->hub_vbus_reg)) {
	ret = regulator_enable(smsc_hub->hub_vbus_reg);
	if (ret) {
	dev_err(&pdev->dev, "unable to enable hub_vbus\n");
	goto uninit_gpio;
	}
	}

	ret = i2c_add_driver(&hsic_hub_driver);
	if (ret < 0) {
	dev_err(&pdev->dev, "failed to add I2C hsic_hub_driver\n");
	goto i2c_add_fail;
	}
	usleep_range(10000, 12000);
	i2c_adap = i2c_get_adapter(SMSC_GSBI_I2C_BUS_ID);

	if (!i2c_adap) {
	dev_err(&pdev->dev, "failed to get i2c adapter\n");
	i2c_del_driver(&hsic_hub_driver);
	goto i2c_add_fail;
	}

	memset(&i2c_info, 0, sizeof(struct i2c_board_info));
	strlcpy(i2c_info.type, "i2c_hsic_hub", I2C_NAME_SIZE);

	smsc_hub->client = i2c_new_probed_device(i2c_adap, &i2c_info,
	normal_i2c, NULL);
	i2c_put_adapter(i2c_adap);
	if (!smsc_hub->client)
	dev_err(&pdev->dev, "failed to connect to smsc_hub"
	"through I2C\n");

	i2c_add_fail:
	pm_runtime_set_active(&pdev->dev);
	pm_runtime_enable(&pdev->dev);

	return 0;

	uninit_gpio:
	msm_hsic_hub_init_gpio(smsc_hub, 0);
	uninit_clock:
	msm_hsic_hub_init_clock(smsc_hub, 0);
	uninit_vdd:
	msm_hsic_hub_init_vdd(smsc_hub, 0);

	return ret;
	}

	static int smsc_hub_remove(struct platform_device *pdev)
	{
	const struct smsc_hub_platform_data *pdata;

	pdata = pdev->dev.platform_data;
	if (smsc_hub->client) {
	i2c_unregister_device(smsc_hub->client);
	smsc_hub->client = NULL;
	i2c_del_driver(&hsic_hub_driver);
	}
	pm_runtime_disable(&pdev->dev);

	if (!IS_ERR(smsc_hub->hub_vbus_reg))
	regulator_disable(smsc_hub->hub_vbus_reg);
	msm_hsic_hub_init_gpio(smsc_hub, 0);
	msm_hsic_hub_init_clock(smsc_hub, 0);
	msm_hsic_hub_init_vdd(smsc_hub, 0);

	return 0;
	}

	#ifdef CONFIG_PM_RUNTIME
	static int msm_smsc_runtime_idle(struct device *dev)
	{
	dev_dbg(dev, "SMSC HUB runtime idle\n");

	return 0;
	}

	static int smsc_hub_lpm_enter(struct device *dev)
	{
	int ret = 0;

	if (smsc_hub->xo_handle) {
	ret = msm_xo_mode_vote(smsc_hub->xo_handle, MSM_XO_MODE_OFF);
	if (ret) {
	pr_err("%s: failed to devote for TCXO\n"
	"D1 buffer%d\n", __func__, ret);
	}
	}
	return ret;
	}

	static int smsc_hub_lpm_exit(struct device *dev)
	{
	int ret = 0;

	if (smsc_hub->xo_handle) {
	ret = msm_xo_mode_vote(smsc_hub->xo_handle, MSM_XO_MODE_ON);
	if (ret) {
	pr_err("%s: failed to vote for TCXO\n"
	"D1 buffer%d\n", __func__, ret);
	}
	}
	return ret;
	}
	#endif

	#ifdef CONFIG_PM
	static const struct dev_pm_ops smsc_hub_dev_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(smsc_hub_lpm_enter, smsc_hub_lpm_exit)
	SET_RUNTIME_PM_OPS(smsc_hub_lpm_enter, smsc_hub_lpm_exit,
	msm_smsc_runtime_idle)
	};
	#endif

	static const struct of_device_id hsic_hub_dt_match[] = {
	{ .compatible = "qcom,hsic-smsc-hub",
	},
	{}
	};
	MODULE_DEVICE_TABLE(of, hsic_hub_dt_match);

	static struct platform_driver smsc_hub_driver = {
	.driver = {
	.name = "msm_smsc_hub",
	.owner = THIS_MODULE,
	#ifdef CONFIG_PM
	.pm = &smsc_hub_dev_pm_ops,
	#endif
	.of_match_table = hsic_hub_dt_match,
	},
	.probe = smsc_hub_probe,
	.remove = smsc_hub_remove,
	};

	static int __init smsc_hub_init(void)
	{
	return platform_driver_register(&smsc_hub_driver);
	}

	static void __exit smsc_hub_exit(void)
	{
	platform_driver_unregister(&smsc_hub_driver);
	}
	subsys_initcall(smsc_hub_init);
	module_exit(smsc_hub_exit);

	MODULE_LICENSE("GPL v2");
	MODULE_DESCRIPTION("SMSC HSIC HUB driver");