[media] mfd: Add the main bulk of core driver for SI476x code

This patch adds main part(out of three) of the I2C driver for the
"core" of MFD device.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/mfd/si476x-i2c.c

+/*
+ * 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\n");
+	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)\n",
+			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)\n",
+			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)\n",
+			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)\n",
+			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)\n",
+			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)\n",
+			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)\n",
+			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)\n", 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\n");
+		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, false);
+			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, false);
+			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.\n", 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:\n %*ph\n",
+				sizeof(report.rds), report.rds);
+		}
+		dev_dbg(&core->client->dev, "Drrrrained!\n");
+		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.\n");
+
+	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\n");
+		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\n");
+		atomic_set(&core->cts, 1);
+		wake_up(&core->command);
+	}
+
+	if (status & SI476X_FM_RDS_INT) {
+		dev_dbg(&core->client->dev, "[interrupt] RDSINT\n");
+		si476x_core_start_rds_drainer_once(core);
+	}
+
+	if (status & SI476X_STC_INT) {
+		dev_dbg(&core->client->dev, "[interrupt] STCINT\n");
+		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\n",
+		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'\n");
+		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\n",
+			rval);
+		return rval;
+	}
+
+	i2c_set_clientdata(client, core);
+
+	atomic_set(&core->is_alive, 0);
+	core->power_state = SI476X_POWER_DOWN;
+
+	pdata = client->dev.platform_data;
+	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\n", 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_err(&client->dev, "No platform data provided\n");
+		return -EINVAL;
+	}
+
+	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\n");
+		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\n");
+		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\n",
+				client->irq);
+			goto free_kfifo;
+		}
+		disable_irq(client->irq);
+		dev_dbg(&client->dev, "IRQ requested.\n");
+
+		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\n");
+
+		core->rds_fifo_depth = 5;
+	}
+
+	core->chip_id = id->driver_data;
+
+	rval = si476x_core_get_revision_info(core);
+	if (rval < 0) {
+		rval = -ENODEV;
+		goto free_kfifo;
+	}
+
+	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_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");