drivers/mailbox/imx-mailbox.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2018 Pengutronix, Oleksij Rempel <o.rempel@pengutronix.de>
  */

 #include <linux/clk.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/mailbox_controller.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/slab.h>

 /* Transmit Register */
 #define IMX_MU_xTRn(x)		(0x00 + 4 * (x))
 /* Receive Register */
 #define IMX_MU_xRRn(x)		(0x10 + 4 * (x))
 /* Status Register */
 #define IMX_MU_xSR		0x20
 #define IMX_MU_xSR_GIPn(x)	BIT(28 + (3 - (x)))
 #define IMX_MU_xSR_RFn(x)	BIT(24 + (3 - (x)))
 #define IMX_MU_xSR_TEn(x)	BIT(20 + (3 - (x)))
 #define IMX_MU_xSR_BRDIP	BIT(9)

 /* Control Register */
 #define IMX_MU_xCR		0x24
 /* General Purpose Interrupt Enable */
 #define IMX_MU_xCR_GIEn(x)	BIT(28 + (3 - (x)))
 /* Receive Interrupt Enable */
 #define IMX_MU_xCR_RIEn(x)	BIT(24 + (3 - (x)))
 /* Transmit Interrupt Enable */
 #define IMX_MU_xCR_TIEn(x)	BIT(20 + (3 - (x)))
 /* General Purpose Interrupt Request */
 #define IMX_MU_xCR_GIRn(x)	BIT(16 + (3 - (x)))

 #define IMX_MU_CHANS		16
 #define IMX_MU_CHAN_NAME_SIZE	20

 enum imx_mu_chan_type {
 	IMX_MU_TYPE_TX,		/* Tx */
 	IMX_MU_TYPE_RX,		/* Rx */
 	IMX_MU_TYPE_TXDB,	/* Tx doorbell */
 	IMX_MU_TYPE_RXDB,	/* Rx doorbell */
 };

 struct imx_mu_con_priv {
 	unsigned int		idx;
 	char			irq_desc[IMX_MU_CHAN_NAME_SIZE];
 	enum imx_mu_chan_type	type;
 	struct mbox_chan	*chan;
 	struct tasklet_struct	txdb_tasklet;
 };

 struct imx_mu_priv {
 	struct device		*dev;
 	void __iomem		*base;
 	spinlock_t		xcr_lock; /* control register lock */

 	struct mbox_controller	mbox;
 	struct mbox_chan	mbox_chans[IMX_MU_CHANS];

 	struct imx_mu_con_priv  con_priv[IMX_MU_CHANS];
 	struct clk		*clk;
 	int			irq;

 	bool			side_b;
 };

 static struct imx_mu_priv *to_imx_mu_priv(struct mbox_controller *mbox)
 {
 	return container_of(mbox, struct imx_mu_priv, mbox);
 }

 static void imx_mu_write(struct imx_mu_priv *priv, u32 val, u32 offs)
 {
 	iowrite32(val, priv->base + offs);
 }

 static u32 imx_mu_read(struct imx_mu_priv *priv, u32 offs)
 {
 	return ioread32(priv->base + offs);
 }

 static u32 imx_mu_xcr_rmw(struct imx_mu_priv *priv, u32 set, u32 clr)
 {
 	unsigned long flags;
 	u32 val;

 	spin_lock_irqsave(&priv->xcr_lock, flags);
 	val = imx_mu_read(priv, IMX_MU_xCR);
 	val &= ~clr;
 	val |= set;
 	imx_mu_write(priv, val, IMX_MU_xCR);
 	spin_unlock_irqrestore(&priv->xcr_lock, flags);

 	return val;
 }

 static void imx_mu_txdb_tasklet(unsigned long data)
 {
 	struct imx_mu_con_priv *cp = (struct imx_mu_con_priv *)data;

 	mbox_chan_txdone(cp->chan, 0);
 }

 static irqreturn_t imx_mu_isr(int irq, void *p)
 {
 	struct mbox_chan *chan = p;
 	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
 	struct imx_mu_con_priv *cp = chan->con_priv;
 	u32 val, ctrl, dat;

 	ctrl = imx_mu_read(priv, IMX_MU_xCR);
 	val = imx_mu_read(priv, IMX_MU_xSR);

 	switch (cp->type) {
 	case IMX_MU_TYPE_TX:
 		val &= IMX_MU_xSR_TEn(cp->idx) &
 			(ctrl & IMX_MU_xCR_TIEn(cp->idx));
 		break;
 	case IMX_MU_TYPE_RX:
 		val &= IMX_MU_xSR_RFn(cp->idx) &
 			(ctrl & IMX_MU_xCR_RIEn(cp->idx));
 		break;
 	case IMX_MU_TYPE_RXDB:
 		val &= IMX_MU_xSR_GIPn(cp->idx) &
 			(ctrl & IMX_MU_xCR_GIEn(cp->idx));
 		break;
 	default:
 		break;
 	}

 	if (!val)
 		return IRQ_NONE;

 	if (val == IMX_MU_xSR_TEn(cp->idx)) {
 		imx_mu_xcr_rmw(priv, 0, IMX_MU_xCR_TIEn(cp->idx));
 		mbox_chan_txdone(chan, 0);
 	} else if (val == IMX_MU_xSR_RFn(cp->idx)) {
 		dat = imx_mu_read(priv, IMX_MU_xRRn(cp->idx));
 		mbox_chan_received_data(chan, (void *)&dat);
 	} else if (val == IMX_MU_xSR_GIPn(cp->idx)) {
 		imx_mu_write(priv, IMX_MU_xSR_GIPn(cp->idx), IMX_MU_xSR);
 		mbox_chan_received_data(chan, NULL);
 	} else {
 		dev_warn_ratelimited(priv->dev, "Not handled interrupt\n");
 		return IRQ_NONE;
 	}

 	return IRQ_HANDLED;
 }

 static int imx_mu_send_data(struct mbox_chan *chan, void *data)
 {
 	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
 	struct imx_mu_con_priv *cp = chan->con_priv;
 	u32 *arg = data;

 	switch (cp->type) {
 	case IMX_MU_TYPE_TX:
 		imx_mu_write(priv, *arg, IMX_MU_xTRn(cp->idx));
 		imx_mu_xcr_rmw(priv, IMX_MU_xCR_TIEn(cp->idx), 0);
 		break;
 	case IMX_MU_TYPE_TXDB:
 		imx_mu_xcr_rmw(priv, IMX_MU_xCR_GIRn(cp->idx), 0);
 		tasklet_schedule(&cp->txdb_tasklet);
 		break;
 	default:
 		dev_warn_ratelimited(priv->dev, "Send data on wrong channel type: %d\n", cp->type);
 		return -EINVAL;
 	}

 	return 0;
 }

 static int imx_mu_startup(struct mbox_chan *chan)
 {
 	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
 	struct imx_mu_con_priv *cp = chan->con_priv;
 	int ret;

 	if (cp->type == IMX_MU_TYPE_TXDB) {
 		/* Tx doorbell don't have ACK support */
 		tasklet_init(&cp->txdb_tasklet, imx_mu_txdb_tasklet,
 			     (unsigned long)cp);
 		return 0;
 	}

 	ret = request_irq(priv->irq, imx_mu_isr, IRQF_SHARED, cp->irq_desc,
 			  chan);
 	if (ret) {
 		dev_err(priv->dev,
 			"Unable to acquire IRQ %d\n", priv->irq);
 		return ret;
 	}

 	switch (cp->type) {
 	case IMX_MU_TYPE_RX:
 		imx_mu_xcr_rmw(priv, IMX_MU_xCR_RIEn(cp->idx), 0);
 		break;
 	case IMX_MU_TYPE_RXDB:
 		imx_mu_xcr_rmw(priv, IMX_MU_xCR_GIEn(cp->idx), 0);
 		break;
 	default:
 		break;
 	}

 	return 0;
 }

 static void imx_mu_shutdown(struct mbox_chan *chan)
 {
 	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
 	struct imx_mu_con_priv *cp = chan->con_priv;

 	if (cp->type == IMX_MU_TYPE_TXDB)
 		tasklet_kill(&cp->txdb_tasklet);

 	imx_mu_xcr_rmw(priv, 0,
 		   IMX_MU_xCR_TIEn(cp->idx) | IMX_MU_xCR_RIEn(cp->idx));

 	free_irq(priv->irq, chan);
 }

 static const struct mbox_chan_ops imx_mu_ops = {
 	.send_data = imx_mu_send_data,
 	.startup = imx_mu_startup,
 	.shutdown = imx_mu_shutdown,
 };

 static struct mbox_chan * imx_mu_xlate(struct mbox_controller *mbox,
 				       const struct of_phandle_args *sp)
 {
 	u32 type, idx, chan;

 	if (sp->args_count != 2) {
 		dev_err(mbox->dev, "Invalid argument count %d\n", sp->args_count);
 		return ERR_PTR(-EINVAL);
 	}

 	type = sp->args[0]; /* channel type */
 	idx = sp->args[1]; /* index */
 	chan = type * 4 + idx;

 	if (chan >= mbox->num_chans) {
 		dev_err(mbox->dev, "Not supported channel number: %d. (type: %d, idx: %d)\n", chan, type, idx);
 		return ERR_PTR(-EINVAL);
 	}

 	return &mbox->chans[chan];
 }

 static void imx_mu_init_generic(struct imx_mu_priv *priv)
 {
 	if (priv->side_b)
 		return;

 	/* Set default MU configuration */
 	imx_mu_write(priv, 0, IMX_MU_xCR);
 }

 static int imx_mu_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	struct resource *iomem;
 	struct imx_mu_priv *priv;
 	unsigned int i;
 	int ret;

 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	priv->dev = dev;

 	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	priv->base = devm_ioremap_resource(&pdev->dev, iomem);
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);

 	priv->irq = platform_get_irq(pdev, 0);
 	if (priv->irq < 0)
 		return priv->irq;

 	priv->clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(priv->clk)) {
 		if (PTR_ERR(priv->clk) != -ENOENT)
 			return PTR_ERR(priv->clk);

 		priv->clk = NULL;
 	}

 	ret = clk_prepare_enable(priv->clk);
 	if (ret) {
 		dev_err(dev, "Failed to enable clock\n");
 		return ret;
 	}

 	for (i = 0; i < IMX_MU_CHANS; i++) {
 		struct imx_mu_con_priv *cp = &priv->con_priv[i];

 		cp->idx = i % 4;
 		cp->type = i >> 2;
 		cp->chan = &priv->mbox_chans[i];
 		priv->mbox_chans[i].con_priv = cp;
 		snprintf(cp->irq_desc, sizeof(cp->irq_desc),
 			 "imx_mu_chan[%i-%i]", cp->type, cp->idx);
 	}

 	priv->side_b = of_property_read_bool(np, "fsl,mu-side-b");

 	spin_lock_init(&priv->xcr_lock);

 	priv->mbox.dev = dev;
 	priv->mbox.ops = &imx_mu_ops;
 	priv->mbox.chans = priv->mbox_chans;
 	priv->mbox.num_chans = IMX_MU_CHANS;
 	priv->mbox.of_xlate = imx_mu_xlate;
 	priv->mbox.txdone_irq = true;

 	platform_set_drvdata(pdev, priv);

 	imx_mu_init_generic(priv);

 	return devm_mbox_controller_register(dev, &priv->mbox);
 }

 static int imx_mu_remove(struct platform_device *pdev)
 {
 	struct imx_mu_priv *priv = platform_get_drvdata(pdev);

 	clk_disable_unprepare(priv->clk);

 	return 0;
 }

 static const struct of_device_id imx_mu_dt_ids[] = {
 	{ .compatible = "fsl,imx6sx-mu" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, imx_mu_dt_ids);

 static struct platform_driver imx_mu_driver = {
 	.probe		= imx_mu_probe,
 	.remove		= imx_mu_remove,
 	.driver = {
 		.name	= "imx_mu",
 		.of_match_table = imx_mu_dt_ids,
 	},
 };
 module_platform_driver(imx_mu_driver);

 MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
 MODULE_DESCRIPTION("Message Unit driver for i.MX");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright (c) 2018 Pengutronix, Oleksij Rempel <o.rempel@pengutronix.de>
	*/

	#include <linux/clk.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/mailbox_controller.h>
	#include <linux/module.h>
	#include <linux/of_device.h>
	#include <linux/slab.h>

	/* Transmit Register */
	#define IMX_MU_xTRn(x) (0x00 + 4 * (x))
	/* Receive Register */
	#define IMX_MU_xRRn(x) (0x10 + 4 * (x))
	/* Status Register */
	#define IMX_MU_xSR 0x20
	#define IMX_MU_xSR_GIPn(x) BIT(28 + (3 - (x)))
	#define IMX_MU_xSR_RFn(x) BIT(24 + (3 - (x)))
	#define IMX_MU_xSR_TEn(x) BIT(20 + (3 - (x)))
	#define IMX_MU_xSR_BRDIP BIT(9)

	/* Control Register */
	#define IMX_MU_xCR 0x24
	/* General Purpose Interrupt Enable */
	#define IMX_MU_xCR_GIEn(x) BIT(28 + (3 - (x)))
	/* Receive Interrupt Enable */
	#define IMX_MU_xCR_RIEn(x) BIT(24 + (3 - (x)))
	/* Transmit Interrupt Enable */
	#define IMX_MU_xCR_TIEn(x) BIT(20 + (3 - (x)))
	/* General Purpose Interrupt Request */
	#define IMX_MU_xCR_GIRn(x) BIT(16 + (3 - (x)))

	#define IMX_MU_CHANS 16
	#define IMX_MU_CHAN_NAME_SIZE 20

	enum imx_mu_chan_type {
	IMX_MU_TYPE_TX, /* Tx */
	IMX_MU_TYPE_RX, /* Rx */
	IMX_MU_TYPE_TXDB, /* Tx doorbell */
	IMX_MU_TYPE_RXDB, /* Rx doorbell */
	};

	struct imx_mu_con_priv {
	unsigned int idx;
	char irq_desc[IMX_MU_CHAN_NAME_SIZE];
	enum imx_mu_chan_type type;
	struct mbox_chan *chan;
	struct tasklet_struct txdb_tasklet;
	};

	struct imx_mu_priv {
	struct device *dev;
	void __iomem *base;
	spinlock_t xcr_lock; /* control register lock */

	struct mbox_controller mbox;
	struct mbox_chan mbox_chans[IMX_MU_CHANS];

	struct imx_mu_con_priv con_priv[IMX_MU_CHANS];
	struct clk *clk;
	int irq;

	bool side_b;
	};

	static struct imx_mu_priv to_imx_mu_priv(struct mbox_controller mbox)
	{
	return container_of(mbox, struct imx_mu_priv, mbox);
	}

	static void imx_mu_write(struct imx_mu_priv *priv, u32 val, u32 offs)
	{
	iowrite32(val, priv->base + offs);
	}

	static u32 imx_mu_read(struct imx_mu_priv *priv, u32 offs)
	{
	return ioread32(priv->base + offs);
	}

	static u32 imx_mu_xcr_rmw(struct imx_mu_priv *priv, u32 set, u32 clr)
	{
	unsigned long flags;
	u32 val;

	spin_lock_irqsave(&priv->xcr_lock, flags);
	val = imx_mu_read(priv, IMX_MU_xCR);
	val &= ~clr;
	val \|= set;
	imx_mu_write(priv, val, IMX_MU_xCR);
	spin_unlock_irqrestore(&priv->xcr_lock, flags);

	return val;
	}

	static void imx_mu_txdb_tasklet(unsigned long data)
	{
	struct imx_mu_con_priv cp = (struct imx_mu_con_priv )data;

	mbox_chan_txdone(cp->chan, 0);
	}

	static irqreturn_t imx_mu_isr(int irq, void *p)
	{
	struct mbox_chan *chan = p;
	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
	struct imx_mu_con_priv *cp = chan->con_priv;
	u32 val, ctrl, dat;

	ctrl = imx_mu_read(priv, IMX_MU_xCR);
	val = imx_mu_read(priv, IMX_MU_xSR);

	switch (cp->type) {
	case IMX_MU_TYPE_TX:
	val &= IMX_MU_xSR_TEn(cp->idx) &
	(ctrl & IMX_MU_xCR_TIEn(cp->idx));
	break;
	case IMX_MU_TYPE_RX:
	val &= IMX_MU_xSR_RFn(cp->idx) &
	(ctrl & IMX_MU_xCR_RIEn(cp->idx));
	break;
	case IMX_MU_TYPE_RXDB:
	val &= IMX_MU_xSR_GIPn(cp->idx) &
	(ctrl & IMX_MU_xCR_GIEn(cp->idx));
	break;
	default:
	break;
	}

	if (!val)
	return IRQ_NONE;

	if (val == IMX_MU_xSR_TEn(cp->idx)) {
	imx_mu_xcr_rmw(priv, 0, IMX_MU_xCR_TIEn(cp->idx));
	mbox_chan_txdone(chan, 0);
	} else if (val == IMX_MU_xSR_RFn(cp->idx)) {
	dat = imx_mu_read(priv, IMX_MU_xRRn(cp->idx));
	mbox_chan_received_data(chan, (void *)&dat);
	} else if (val == IMX_MU_xSR_GIPn(cp->idx)) {
	imx_mu_write(priv, IMX_MU_xSR_GIPn(cp->idx), IMX_MU_xSR);
	mbox_chan_received_data(chan, NULL);
	} else {
	dev_warn_ratelimited(priv->dev, "Not handled interrupt\n");
	return IRQ_NONE;
	}

	return IRQ_HANDLED;
	}

	static int imx_mu_send_data(struct mbox_chan chan, void data)
	{
	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
	struct imx_mu_con_priv *cp = chan->con_priv;
	u32 *arg = data;

	switch (cp->type) {
	case IMX_MU_TYPE_TX:
	imx_mu_write(priv, *arg, IMX_MU_xTRn(cp->idx));
	imx_mu_xcr_rmw(priv, IMX_MU_xCR_TIEn(cp->idx), 0);
	break;
	case IMX_MU_TYPE_TXDB:
	imx_mu_xcr_rmw(priv, IMX_MU_xCR_GIRn(cp->idx), 0);
	tasklet_schedule(&cp->txdb_tasklet);
	break;
	default:
	dev_warn_ratelimited(priv->dev, "Send data on wrong channel type: %d\n", cp->type);
	return -EINVAL;
	}

	return 0;
	}

	static int imx_mu_startup(struct mbox_chan *chan)
	{
	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
	struct imx_mu_con_priv *cp = chan->con_priv;
	int ret;

	if (cp->type == IMX_MU_TYPE_TXDB) {
	/* Tx doorbell don't have ACK support */
	tasklet_init(&cp->txdb_tasklet, imx_mu_txdb_tasklet,
	(unsigned long)cp);
	return 0;
	}

	ret = request_irq(priv->irq, imx_mu_isr, IRQF_SHARED, cp->irq_desc,
	chan);
	if (ret) {
	dev_err(priv->dev,
	"Unable to acquire IRQ %d\n", priv->irq);
	return ret;
	}

	switch (cp->type) {
	case IMX_MU_TYPE_RX:
	imx_mu_xcr_rmw(priv, IMX_MU_xCR_RIEn(cp->idx), 0);
	break;
	case IMX_MU_TYPE_RXDB:
	imx_mu_xcr_rmw(priv, IMX_MU_xCR_GIEn(cp->idx), 0);
	break;
	default:
	break;
	}

	return 0;
	}

	static void imx_mu_shutdown(struct mbox_chan *chan)
	{
	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
	struct imx_mu_con_priv *cp = chan->con_priv;

	if (cp->type == IMX_MU_TYPE_TXDB)
	tasklet_kill(&cp->txdb_tasklet);

	imx_mu_xcr_rmw(priv, 0,
	IMX_MU_xCR_TIEn(cp->idx) \| IMX_MU_xCR_RIEn(cp->idx));

	free_irq(priv->irq, chan);
	}

	static const struct mbox_chan_ops imx_mu_ops = {
	.send_data = imx_mu_send_data,
	.startup = imx_mu_startup,
	.shutdown = imx_mu_shutdown,
	};

	static struct mbox_chan * imx_mu_xlate(struct mbox_controller *mbox,
	const struct of_phandle_args *sp)
	{
	u32 type, idx, chan;

	if (sp->args_count != 2) {
	dev_err(mbox->dev, "Invalid argument count %d\n", sp->args_count);
	return ERR_PTR(-EINVAL);
	}

	type = sp->args[0]; /* channel type */
	idx = sp->args[1]; /* index */
	chan = type * 4 + idx;

	if (chan >= mbox->num_chans) {
	dev_err(mbox->dev, "Not supported channel number: %d. (type: %d, idx: %d)\n", chan, type, idx);
	return ERR_PTR(-EINVAL);
	}

	return &mbox->chans[chan];
	}

	static void imx_mu_init_generic(struct imx_mu_priv *priv)
	{
	if (priv->side_b)
	return;

	/* Set default MU configuration */
	imx_mu_write(priv, 0, IMX_MU_xCR);
	}

	static int imx_mu_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct resource *iomem;
	struct imx_mu_priv *priv;
	unsigned int i;
	int ret;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	priv->dev = dev;

	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	priv->base = devm_ioremap_resource(&pdev->dev, iomem);
	if (IS_ERR(priv->base))
	return PTR_ERR(priv->base);

	priv->irq = platform_get_irq(pdev, 0);
	if (priv->irq < 0)
	return priv->irq;

	priv->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(priv->clk)) {
	if (PTR_ERR(priv->clk) != -ENOENT)
	return PTR_ERR(priv->clk);

	priv->clk = NULL;
	}

	ret = clk_prepare_enable(priv->clk);
	if (ret) {
	dev_err(dev, "Failed to enable clock\n");
	return ret;
	}

	for (i = 0; i < IMX_MU_CHANS; i++) {
	struct imx_mu_con_priv *cp = &priv->con_priv[i];

	cp->idx = i % 4;
	cp->type = i >> 2;
	cp->chan = &priv->mbox_chans[i];
	priv->mbox_chans[i].con_priv = cp;
	snprintf(cp->irq_desc, sizeof(cp->irq_desc),
	"imx_mu_chan[%i-%i]", cp->type, cp->idx);
	}

	priv->side_b = of_property_read_bool(np, "fsl,mu-side-b");

	spin_lock_init(&priv->xcr_lock);

	priv->mbox.dev = dev;
	priv->mbox.ops = &imx_mu_ops;
	priv->mbox.chans = priv->mbox_chans;
	priv->mbox.num_chans = IMX_MU_CHANS;
	priv->mbox.of_xlate = imx_mu_xlate;
	priv->mbox.txdone_irq = true;

	platform_set_drvdata(pdev, priv);

	imx_mu_init_generic(priv);

	return devm_mbox_controller_register(dev, &priv->mbox);
	}

	static int imx_mu_remove(struct platform_device *pdev)
	{
	struct imx_mu_priv *priv = platform_get_drvdata(pdev);

	clk_disable_unprepare(priv->clk);

	return 0;
	}

	static const struct of_device_id imx_mu_dt_ids[] = {
	{ .compatible = "fsl,imx6sx-mu" },
	{ },
	};
	MODULE_DEVICE_TABLE(of, imx_mu_dt_ids);

	static struct platform_driver imx_mu_driver = {
	.probe = imx_mu_probe,
	.remove = imx_mu_remove,
	.driver = {
	.name = "imx_mu",
	.of_match_table = imx_mu_dt_ids,
	},
	};
	module_platform_driver(imx_mu_driver);

	MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
	MODULE_DESCRIPTION("Message Unit driver for i.MX");
	MODULE_LICENSE("GPL v2");