/*
   * drivers/mfd/si476x-i2c.c -- Core device driver for si476x MFD
   * device
   *
   * Copyright (C) 2012 Innovative Converged Devices(ICD)
   * Copyright (C) 2013 Andrey Smirnov
   *
   * Author: Andrey Smirnov <andrew.smirnov@gmail.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; version 2 of the License.
   *
   * 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/module.h>
  
  #include <linux/slab.h>
  #include <linux/interrupt.h>
  #include <linux/delay.h>
  #include <linux/gpio.h>
  #include <linux/regulator/consumer.h>
  #include <linux/i2c.h>
  #include <linux/err.h>
  
  #include <linux/mfd/si476x-core.h>
  
  #define SI476X_MAX_IO_ERRORS		10
  #define SI476X_DRIVER_RDS_FIFO_DEPTH	128
  
  /**
   * si476x_core_config_pinmux() - pin function configuration function
   *
   * @core: Core device structure
   *
   * Configure the functions of the pins of the radio chip.
   *
   * The function returns zero in case of succes or negative error code
   * otherwise.
   */
  static int si476x_core_config_pinmux(struct si476x_core *core)
  {
  	int err;
  	dev_dbg(&core->client->dev, "Configuring pinmux
  ");
  	err = si476x_core_cmd_dig_audio_pin_cfg(core,
  						core->pinmux.dclk,
  						core->pinmux.dfs,
  						core->pinmux.dout,
  						core->pinmux.xout);
  	if (err < 0) {
  		dev_err(&core->client->dev,
  			"Failed to configure digital audio pins(err = %d)
  ",
  			err);
  		return err;
  	}
  
  	err = si476x_core_cmd_zif_pin_cfg(core,
  					  core->pinmux.iqclk,
  					  core->pinmux.iqfs,
  					  core->pinmux.iout,
  					  core->pinmux.qout);
  	if (err < 0) {
  		dev_err(&core->client->dev,
  			"Failed to configure ZIF pins(err = %d)
  ",
  			err);
  		return err;
  	}
  
  	err = si476x_core_cmd_ic_link_gpo_ctl_pin_cfg(core,
  						      core->pinmux.icin,
  						      core->pinmux.icip,
  						      core->pinmux.icon,
  						      core->pinmux.icop);
  	if (err < 0) {
  		dev_err(&core->client->dev,
  			"Failed to configure IC-Link/GPO pins(err = %d)
  ",
  			err);
  		return err;
  	}
  
  	err = si476x_core_cmd_ana_audio_pin_cfg(core,
  						core->pinmux.lrout);
  	if (err < 0) {
  		dev_err(&core->client->dev,
  			"Failed to configure analog audio pins(err = %d)
  ",
  			err);
  		return err;
  	}
  
  	err = si476x_core_cmd_intb_pin_cfg(core,
  					   core->pinmux.intb,
  					   core->pinmux.a1);
  	if (err < 0) {
  		dev_err(&core->client->dev,
  			"Failed to configure interrupt pins(err = %d)
  ",
  			err);
  		return err;
  	}
  
  	return 0;
  }
  
  static inline void si476x_core_schedule_polling_work(struct si476x_core *core)
  {
  	schedule_delayed_work(&core->status_monitor,
  			      usecs_to_jiffies(SI476X_STATUS_POLL_US));
  }
  
  /**
   * si476x_core_start() - early chip startup function
   * @core: Core device structure
   * @soft: When set, this flag forces "soft" startup, where "soft"
   * power down is the one done by sending appropriate command instead
   * of using reset pin of the tuner
   *
   * Perform required startup sequence to correctly power
   * up the chip and perform initial configuration. It does the
   * following sequence of actions:
   *       1. Claims and enables the power supplies VD and VIO1 required
   *          for I2C interface of the chip operation.
   *       2. Waits for 100us, pulls the reset line up, enables irq,
   *          waits for another 100us as it is specified by the
   *          datasheet.
   *       3. Sends 'POWER_UP' command to the device with all provided
   *          information about power-up parameters.
   *       4. Configures, pin multiplexor, disables digital audio and
   *          configures interrupt sources.
   *
   * The function returns zero in case of succes or negative error code
   * otherwise.
   */
  int si476x_core_start(struct si476x_core *core, bool soft)
  {
  	struct i2c_client *client = core->client;
  	int err;
  
  	if (!soft) {
  		if (gpio_is_valid(core->gpio_reset))
  			gpio_set_value_cansleep(core->gpio_reset, 1);
  
  		if (client->irq)
  			enable_irq(client->irq);
  
  		udelay(100);
  
  		if (!client->irq) {
  			atomic_set(&core->is_alive, 1);
  			si476x_core_schedule_polling_work(core);
  		}
  	} else {
  		if (client->irq)
  			enable_irq(client->irq);
  		else {
  			atomic_set(&core->is_alive, 1);
  			si476x_core_schedule_polling_work(core);
  		}
  	}
  
  	err = si476x_core_cmd_power_up(core,
  				       &core->power_up_parameters);
  
  	if (err < 0) {
  		dev_err(&core->client->dev,
  			"Power up failure(err = %d)
  ",
  			err);
  		goto disable_irq;
  	}
  
  	if (client->irq)
  		atomic_set(&core->is_alive, 1);
  
  	err = si476x_core_config_pinmux(core);
  	if (err < 0) {
  		dev_err(&core->client->dev,
  			"Failed to configure pinmux(err = %d)
  ",
  			err);
  		goto disable_irq;
  	}
  
  	if (client->irq) {
  		err = regmap_write(core->regmap,
  				   SI476X_PROP_INT_CTL_ENABLE,
  				   SI476X_RDSIEN |
  				   SI476X_STCIEN |
  				   SI476X_CTSIEN);
  		if (err < 0) {
  			dev_err(&core->client->dev,
  				"Failed to configure interrupt sources"
  				"(err = %d)
  ", err);
  			goto disable_irq;
  		}
  	}
  
  	return 0;
  
  disable_irq:
  	if (err == -ENODEV)
  		atomic_set(&core->is_alive, 0);
  
  	if (client->irq)
  		disable_irq(client->irq);
  	else
  		cancel_delayed_work_sync(&core->status_monitor);
  
  	if (gpio_is_valid(core->gpio_reset))
  		gpio_set_value_cansleep(core->gpio_reset, 0);
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(si476x_core_start);
  
  /**
   * si476x_core_stop() - chip power-down function
   * @core: Core device structure
   * @soft: When set, function sends a POWER_DOWN command instead of
   * bringing reset line low
   *
   * Power down the chip by performing following actions:
   * 1. Disable IRQ or stop the polling worker
   * 2. Send the POWER_DOWN command if the power down is soft or bring
   *    reset line low if not.
   *
   * The function returns zero in case of succes or negative error code
   * otherwise.
   */
  int si476x_core_stop(struct si476x_core *core, bool soft)
  {
  	int err = 0;
  	atomic_set(&core->is_alive, 0);
  
  	if (soft) {
  		/* TODO: This probably shoud be a configurable option,
  		 * so it is possible to have the chips keep their
  		 * oscillators running
  		 */
  		struct si476x_power_down_args args = {
  			.xosc = false,
  		};
  		err = si476x_core_cmd_power_down(core, &args);
  	}
  
  	/* We couldn't disable those before
  	 * 'si476x_core_cmd_power_down' since we expect to get CTS
  	 * interrupt */
  	if (core->client->irq)
  		disable_irq(core->client->irq);
  	else
  		cancel_delayed_work_sync(&core->status_monitor);
  
  	if (!soft) {
  		if (gpio_is_valid(core->gpio_reset))
  			gpio_set_value_cansleep(core->gpio_reset, 0);
  	}
  	return err;
  }
  EXPORT_SYMBOL_GPL(si476x_core_stop);
  
  /**
   * si476x_core_set_power_state() - set the level at which the power is
   * supplied for the chip.
   * @core: Core device structure
   * @next_state: enum si476x_power_state describing power state to
   *              switch to.
   *
   * Switch on all the required power supplies
   *
   * This function returns 0 in case of suvccess and negative error code
   * otherwise.
   */
  int si476x_core_set_power_state(struct si476x_core *core,
  				enum si476x_power_state next_state)
  {
  	/*
  	   It is not clear form the datasheet if it is possible to
  	   work with device if not all power domains are operational.
  	   So for now the power-up policy is "power-up all the things!"
  	 */
  	int err = 0;
  
  	if (core->power_state == SI476X_POWER_INCONSISTENT) {
  		dev_err(&core->client->dev,
  			"The device in inconsistent power state
  ");
  		return -EINVAL;
  	}
  
  	if (next_state != core->power_state) {
  		switch (next_state) {
  		case SI476X_POWER_UP_FULL:
  			err = regulator_bulk_enable(ARRAY_SIZE(core->supplies),
  						    core->supplies);
  			if (err < 0) {
  				core->power_state = SI476X_POWER_INCONSISTENT;
  				break;
  			}
  			/*
  			 * Startup timing diagram recommends to have a
  			 * 100 us delay between enabling of the power
  			 * supplies and turning the tuner on.
  			 */
  			udelay(100);
  
  			err = si476x_core_start(core, true);
  			if (err < 0)
  				goto disable_regulators;
  
  			core->power_state = next_state;
  			break;
  
  		case SI476X_POWER_DOWN:
  			core->power_state = next_state;
  			err = si476x_core_stop(core, true);
  			if (err < 0)
  				core->power_state = SI476X_POWER_INCONSISTENT;
  disable_regulators:
  			err = regulator_bulk_disable(ARRAY_SIZE(core->supplies),
  						     core->supplies);
  			if (err < 0)
  				core->power_state = SI476X_POWER_INCONSISTENT;
  			break;
  		default:
  			BUG();
  		}
  	}
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(si476x_core_set_power_state);
  
  /**
   * si476x_core_report_drainer_stop() - mark the completion of the RDS
   * buffer drain porcess by the worker.
   *
   * @core: Core device structure
   */
  static inline void si476x_core_report_drainer_stop(struct si476x_core *core)
  {
  	mutex_lock(&core->rds_drainer_status_lock);
  	core->rds_drainer_is_working = false;
  	mutex_unlock(&core->rds_drainer_status_lock);
  }
  
  /**
   * si476x_core_start_rds_drainer_once() - start RDS drainer worker if
   * ther is none working, do nothing otherwise
   *
   * @core: Datastructure corresponding to the chip.
   */
  static inline void si476x_core_start_rds_drainer_once(struct si476x_core *core)
  {
  	mutex_lock(&core->rds_drainer_status_lock);
  	if (!core->rds_drainer_is_working) {
  		core->rds_drainer_is_working = true;
  		schedule_work(&core->rds_fifo_drainer);
  	}
  	mutex_unlock(&core->rds_drainer_status_lock);
  }
  /**
   * si476x_drain_rds_fifo() - RDS buffer drainer.
   * @work: struct work_struct being ppassed to the function by the
   * kernel.
   *
   * Drain the contents of the RDS FIFO of
   */
  static void si476x_core_drain_rds_fifo(struct work_struct *work)
  {
  	int err;
  
  	struct si476x_core *core = container_of(work, struct si476x_core,
  						rds_fifo_drainer);
  
  	struct si476x_rds_status_report report;
  
  	si476x_core_lock(core);
  	err = si476x_core_cmd_fm_rds_status(core, true, false, false, &report);
  	if (!err) {
  		int i = report.rdsfifoused;
  		dev_dbg(&core->client->dev,
  			"%d elements in RDS FIFO. Draining.
  ", i);
  		for (; i > 0; --i) {
  			err = si476x_core_cmd_fm_rds_status(core, false, false,
  							    (i == 1), &report);
  			if (err < 0)
  				goto unlock;
  
  			kfifo_in(&core->rds_fifo, report.rds,
  				 sizeof(report.rds));
  			dev_dbg(&core->client->dev, "RDS data:
   %*ph
  ",
  				(int)sizeof(report.rds), report.rds);
  		}
  		dev_dbg(&core->client->dev, "Drrrrained!
  ");
  		wake_up_interruptible(&core->rds_read_queue);
  	}
  
  unlock:
  	si476x_core_unlock(core);
  	si476x_core_report_drainer_stop(core);
  }
  
  /**
   * si476x_core_pronounce_dead()
   *
   * @core: Core device structure
   *
   * Mark the device as being dead and wake up all potentially waiting
   * threads of execution.
   *
   */
  static void si476x_core_pronounce_dead(struct si476x_core *core)
  {
  	dev_info(&core->client->dev, "Core device is dead.
  ");
  
  	atomic_set(&core->is_alive, 0);
  
  	/* Wake up al possible waiting processes */
  	wake_up_interruptible(&core->rds_read_queue);
  
  	atomic_set(&core->cts, 1);
  	wake_up(&core->command);
  
  	atomic_set(&core->stc, 1);
  	wake_up(&core->tuning);
  }
  
  /**
   * si476x_core_i2c_xfer()
   *
   * @core: Core device structure
   * @type: Transfer type
   * @buf: Transfer buffer for/with data
   * @count: Transfer buffer size
   *
   * Perfrom and I2C transfer(either read or write) and keep a counter
   * of I/O errors. If the error counter rises above the threshold
   * pronounce device dead.
   *
   * The function returns zero on succes or negative error code on
   * failure.
   */
  int si476x_core_i2c_xfer(struct si476x_core *core,
  		    enum si476x_i2c_type type,
  		    char *buf, int count)
  {
  	static int io_errors_count;
  	int err;
  	if (type == SI476X_I2C_SEND)
  		err = i2c_master_send(core->client, buf, count);
  	else
  		err = i2c_master_recv(core->client, buf, count);
  
  	if (err < 0) {
  		if (io_errors_count++ > SI476X_MAX_IO_ERRORS)
  			si476x_core_pronounce_dead(core);
  	} else {
  		io_errors_count = 0;
  	}
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(si476x_core_i2c_xfer);
  
  /**
   * si476x_get_status()
   * @core: Core device structure
   *
   * Get the status byte of the core device by berforming one byte I2C
   * read.
   *
   * The function returns a status value or a negative error code on
   * error.
   */
  static int si476x_core_get_status(struct si476x_core *core)
  {
  	u8 response;
  	int err = si476x_core_i2c_xfer(core, SI476X_I2C_RECV,
  				  &response, sizeof(response));
  
  	return (err < 0) ? err : response;
  }
  
  /**
   * si476x_get_and_signal_status() - IRQ dispatcher
   * @core: Core device structure
   *
   * Dispatch the arrived interrupt request based on the value of the
   * status byte reported by the tuner.
   *
   */
  static void si476x_core_get_and_signal_status(struct si476x_core *core)
  {
  	int status = si476x_core_get_status(core);
  	if (status < 0) {
  		dev_err(&core->client->dev, "Failed to get status
  ");
  		return;
  	}
  
  	if (status & SI476X_CTS) {
  		/* Unfortunately completions could not be used for
  		 * signalling CTS since this flag cannot be cleared
  		 * in status byte, and therefore once it becomes true
  		 * multiple calls to 'complete' would cause the
  		 * commands following the current one to be completed
  		 * before they actually are */
  		dev_dbg(&core->client->dev, "[interrupt] CTSINT
  ");
  		atomic_set(&core->cts, 1);
  		wake_up(&core->command);
  	}
  
  	if (status & SI476X_FM_RDS_INT) {
  		dev_dbg(&core->client->dev, "[interrupt] RDSINT
  ");
  		si476x_core_start_rds_drainer_once(core);
  	}
  
  	if (status & SI476X_STC_INT) {
  		dev_dbg(&core->client->dev, "[interrupt] STCINT
  ");
  		atomic_set(&core->stc, 1);
  		wake_up(&core->tuning);
  	}
  }
  
  static void si476x_core_poll_loop(struct work_struct *work)
  {
  	struct si476x_core *core = SI476X_WORK_TO_CORE(work);
  
  	si476x_core_get_and_signal_status(core);
  
  	if (atomic_read(&core->is_alive))
  		si476x_core_schedule_polling_work(core);
  }
  
  static irqreturn_t si476x_core_interrupt(int irq, void *dev)
  {
  	struct si476x_core *core = dev;
  
  	si476x_core_get_and_signal_status(core);
  
  	return IRQ_HANDLED;
  }
  
  /**
   * si476x_firmware_version_to_revision()
   * @core: Core device structure
   * @major:  Firmware major number
   * @minor1: Firmware first minor number
   * @minor2: Firmware second minor number
   *
   * Convert a chip's firmware version number into an offset that later
   * will be used to as offset in "vtable" of tuner functions
   *
   * This function returns a positive offset in case of success and a -1
   * in case of failure.
   */
  static int si476x_core_fwver_to_revision(struct si476x_core *core,
  					 int func, int major,
  					 int minor1, int minor2)
  {
  	switch (func) {
  	case SI476X_FUNC_FM_RECEIVER:
  		switch (major) {
  		case 5:
  			return SI476X_REVISION_A10;
  		case 8:
  			return SI476X_REVISION_A20;
  		case 10:
  			return SI476X_REVISION_A30;
  		default:
  			goto unknown_revision;
  		}
  	case SI476X_FUNC_AM_RECEIVER:
  		switch (major) {
  		case 5:
  			return SI476X_REVISION_A10;
  		case 7:
  			return SI476X_REVISION_A20;
  		case 9:
  			return SI476X_REVISION_A30;
  		default:
  			goto unknown_revision;
  		}
  	case SI476X_FUNC_WB_RECEIVER:
  		switch (major) {
  		case 3:
  			return SI476X_REVISION_A10;
  		case 5:
  			return SI476X_REVISION_A20;
  		case 7:
  			return SI476X_REVISION_A30;
  		default:
  			goto unknown_revision;
  		}
  	case SI476X_FUNC_BOOTLOADER:
  	default:		/* FALLTHROUG */
  		BUG();
  		return -1;
  	}
  
  unknown_revision:
  	dev_err(&core->client->dev,
  		"Unsupported version of the firmware: %d.%d.%d, "
  		"reverting to A10 comptible functions
  ",
  		major, minor1, minor2);
  
  	return SI476X_REVISION_A10;
  }
  
  /**
   * si476x_get_revision_info()
   * @core: Core device structure
   *
   * Get the firmware version number of the device. It is done in
   * following three steps:
   *    1. Power-up the device
   *    2. Send the 'FUNC_INFO' command
   *    3. Powering the device down.
   *
   * The function return zero on success and a negative error code on
   * failure.
   */
  static int si476x_core_get_revision_info(struct si476x_core *core)
  {
  	int rval;
  	struct si476x_func_info info;
  
  	si476x_core_lock(core);
  	rval = si476x_core_set_power_state(core, SI476X_POWER_UP_FULL);
  	if (rval < 0)
  		goto exit;
  
  	rval = si476x_core_cmd_func_info(core, &info);
  	if (rval < 0)
  		goto power_down;
  
  	core->revision = si476x_core_fwver_to_revision(core, info.func,
  						       info.firmware.major,
  						       info.firmware.minor[0],
  						       info.firmware.minor[1]);
  power_down:
  	si476x_core_set_power_state(core, SI476X_POWER_DOWN);
  exit:
  	si476x_core_unlock(core);
  
  	return rval;
  }
  
  bool si476x_core_has_am(struct si476x_core *core)
  {
  	return core->chip_id == SI476X_CHIP_SI4761 ||
  		core->chip_id == SI476X_CHIP_SI4764;
  }
  EXPORT_SYMBOL_GPL(si476x_core_has_am);
  
  bool si476x_core_has_diversity(struct si476x_core *core)
  {
  	return core->chip_id == SI476X_CHIP_SI4764;
  }
  EXPORT_SYMBOL_GPL(si476x_core_has_diversity);
  
  bool si476x_core_is_a_secondary_tuner(struct si476x_core *core)
  {
  	return si476x_core_has_diversity(core) &&
  		(core->diversity_mode == SI476X_PHDIV_SECONDARY_ANTENNA ||
  		 core->diversity_mode == SI476X_PHDIV_SECONDARY_COMBINING);
  }
  EXPORT_SYMBOL_GPL(si476x_core_is_a_secondary_tuner);
  
  bool si476x_core_is_a_primary_tuner(struct si476x_core *core)
  {
  	return si476x_core_has_diversity(core) &&
  		(core->diversity_mode == SI476X_PHDIV_PRIMARY_ANTENNA ||
  		 core->diversity_mode == SI476X_PHDIV_PRIMARY_COMBINING);
  }
  EXPORT_SYMBOL_GPL(si476x_core_is_a_primary_tuner);
  
  bool si476x_core_is_in_am_receiver_mode(struct si476x_core *core)
  {
  	return si476x_core_has_am(core) &&
  		(core->power_up_parameters.func == SI476X_FUNC_AM_RECEIVER);
  }
  EXPORT_SYMBOL_GPL(si476x_core_is_in_am_receiver_mode);
  
  bool si476x_core_is_powered_up(struct si476x_core *core)
  {
  	return core->power_state == SI476X_POWER_UP_FULL;
  }
  EXPORT_SYMBOL_GPL(si476x_core_is_powered_up);
  
  static int si476x_core_probe(struct i2c_client *client,
  			     const struct i2c_device_id *id)
  {
  	int rval;
  	struct si476x_core          *core;
  	struct si476x_platform_data *pdata;
  	struct mfd_cell *cell;
  	int              cell_num;
  
  	core = devm_kzalloc(&client->dev, sizeof(*core), GFP_KERNEL);
  	if (!core) {
  		dev_err(&client->dev,
  			"failed to allocate 'struct si476x_core'
  ");
  		return -ENOMEM;
  	}
  	core->client = client;
  
  	core->regmap = devm_regmap_init_si476x(core);
  	if (IS_ERR(core->regmap)) {
  		rval = PTR_ERR(core->regmap);
  		dev_err(&client->dev,
  			"Failed to allocate register map: %d
  ",
  			rval);
  		return rval;
  	}
  
  	i2c_set_clientdata(client, core);
  
  	atomic_set(&core->is_alive, 0);
  	core->power_state = SI476X_POWER_DOWN;
  
  	pdata = dev_get_platdata(&client->dev);
  	if (pdata) {
  		memcpy(&core->power_up_parameters,
  		       &pdata->power_up_parameters,
  		       sizeof(core->power_up_parameters));
  
  		core->gpio_reset = -1;
  		if (gpio_is_valid(pdata->gpio_reset)) {
  			rval = gpio_request(pdata->gpio_reset, "si476x reset");
  			if (rval) {
  				dev_err(&client->dev,
  					"Failed to request gpio: %d
  ", rval);
  				return rval;
  			}
  			core->gpio_reset = pdata->gpio_reset;
  			gpio_direction_output(core->gpio_reset, 0);
  		}
  
  		core->diversity_mode = pdata->diversity_mode;
  		memcpy(&core->pinmux, &pdata->pinmux,
  		       sizeof(struct si476x_pinmux));
  	} else {
  		dev_warn(&client->dev, "Using default platform data.
  ");
  		core->power_up_parameters.xcload = 0x28;
  		core->power_up_parameters.func = SI476X_FUNC_FM_RECEIVER;
  		core->power_up_parameters.freq = SI476X_FREQ_37P209375_MHZ;
  		core->diversity_mode = SI476X_PHDIV_DISABLED;
  		core->pinmux.dclk = SI476X_DCLK_DAUDIO;
  		core->pinmux.dfs  = SI476X_DFS_DAUDIO;
  		core->pinmux.dout = SI476X_DOUT_I2S_OUTPUT;
  		core->pinmux.xout = SI476X_XOUT_TRISTATE;
  	}
  
  	core->supplies[0].supply = "vd";
  	core->supplies[1].supply = "va";
  	core->supplies[2].supply = "vio1";
  	core->supplies[3].supply = "vio2";
  
  	rval = devm_regulator_bulk_get(&client->dev,
  				       ARRAY_SIZE(core->supplies),
  				       core->supplies);
  	if (rval) {
  		dev_err(&client->dev, "Failet to gett all of the regulators
  ");
  		goto free_gpio;
  	}
  
  	mutex_init(&core->cmd_lock);
  	init_waitqueue_head(&core->command);
  	init_waitqueue_head(&core->tuning);
  
  	rval = kfifo_alloc(&core->rds_fifo,
  			   SI476X_DRIVER_RDS_FIFO_DEPTH *
  			   sizeof(struct v4l2_rds_data),
  			   GFP_KERNEL);
  	if (rval) {
  		dev_err(&client->dev, "Could not alloate the FIFO
  ");
  		goto free_gpio;
  	}
  	mutex_init(&core->rds_drainer_status_lock);
  	init_waitqueue_head(&core->rds_read_queue);
  	INIT_WORK(&core->rds_fifo_drainer, si476x_core_drain_rds_fifo);
  
  	if (client->irq) {
  		rval = devm_request_threaded_irq(&client->dev,
  						 client->irq, NULL,
  						 si476x_core_interrupt,
  						 IRQF_TRIGGER_FALLING,
  						 client->name, core);
  		if (rval < 0) {
  			dev_err(&client->dev, "Could not request IRQ %d
  ",
  				client->irq);
  			goto free_kfifo;
  		}
  		disable_irq(client->irq);
  		dev_dbg(&client->dev, "IRQ requested.
  ");
  
  		core->rds_fifo_depth = 20;
  	} else {
  		INIT_DELAYED_WORK(&core->status_monitor,
  				  si476x_core_poll_loop);
  		dev_info(&client->dev,
  			 "No IRQ number specified, will use polling
  ");
  
  		core->rds_fifo_depth = 5;
  	}
  
  	core->chip_id = id->driver_data;
  
  	/* Power down si476x first */
  	core->power_state = SI476X_POWER_UP_FULL;
  	si476x_core_set_power_state(core, SI476X_POWER_DOWN);
  
  	rval = si476x_core_get_revision_info(core);
  	if (rval < 0) {
  		rval = -ENODEV;
  		goto free_kfifo;
  	}
  
  	if (of_property_read_bool(client->dev.of_node, "revision-a10"))
  		core->revision = SI476X_REVISION_A10;
  
  	cell_num = 0;
  
  	cell = &core->cells[SI476X_RADIO_CELL];
  	cell->name = "si476x-radio";
  	cell_num++;
  
  #ifdef CONFIG_SND_SOC_SI476X
  	if ((core->chip_id == SI476X_CHIP_SI4761 ||
  	     core->chip_id == SI476X_CHIP_SI4764)	&&
  	    core->pinmux.dclk == SI476X_DCLK_DAUDIO     &&
  	    core->pinmux.dfs  == SI476X_DFS_DAUDIO      &&
  	    core->pinmux.dout == SI476X_DOUT_I2S_OUTPUT &&
  	    core->pinmux.xout == SI476X_XOUT_TRISTATE) {
  		cell = &core->cells[SI476X_CODEC_CELL];
  		cell->name          = "si476x-codec";
  		cell->of_compatible = "si476x-codec";
  		cell_num++;
  	}
  #endif
  	rval = mfd_add_devices(&client->dev,
  			       (client->adapter->nr << 8) + client->addr,
  			       core->cells, cell_num,
  			       NULL, 0, NULL);
  	if (!rval)
  		return 0;
  
  free_kfifo:
  	kfifo_free(&core->rds_fifo);
  
  free_gpio:
  	if (gpio_is_valid(core->gpio_reset))
  		gpio_free(core->gpio_reset);
  
  	return rval;
  }
  
  static int si476x_core_remove(struct i2c_client *client)
  {
  	struct si476x_core *core = i2c_get_clientdata(client);
  
  	si476x_core_pronounce_dead(core);
  	mfd_remove_devices(&client->dev);
  
  	if (client->irq)
  		disable_irq(client->irq);
  	else
  		cancel_delayed_work_sync(&core->status_monitor);
  
  	kfifo_free(&core->rds_fifo);
  
  	if (gpio_is_valid(core->gpio_reset))
  		gpio_free(core->gpio_reset);
  
  	return 0;
  }
  
  
  static const struct i2c_device_id si476x_id[] = {
  	{ "si4761", SI476X_CHIP_SI4761 },
  	{ "si4764", SI476X_CHIP_SI4764 },
  	{ "si4768", SI476X_CHIP_SI4768 },
  	{ },
  };
  MODULE_DEVICE_TABLE(i2c, si476x_id);
  
  static struct i2c_driver si476x_core_driver = {
  	.driver		= {
  		.name	= "si476x-core",
  		.owner  = THIS_MODULE,
  	},
  	.probe		= si476x_core_probe,
  	.remove         = si476x_core_remove,
  	.id_table       = si476x_id,
  };
  module_i2c_driver(si476x_core_driver);
  
  
  MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
  MODULE_DESCRIPTION("Si4761/64/68 AM/FM MFD core device driver");
  MODULE_LICENSE("GPL");