drivers/dma/stm32-dmamux.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *
  * Copyright (C) STMicroelectronics SA 2017
  * Author(s): M'boumba Cedric Madianga <cedric.madianga@gmail.com>
  *            Pierre-Yves Mordret <pierre-yves.mordret@st.com>
  *
  * DMA Router driver for STM32 DMA MUX
  *
  * Based on TI DMA Crossbar driver
  */

 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/of_dma.h>
 #include <linux/pm_runtime.h>
 #include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>

 #define STM32_DMAMUX_CCR(x)		(0x4 * (x))
 #define STM32_DMAMUX_MAX_DMA_REQUESTS	32
 #define STM32_DMAMUX_MAX_REQUESTS	255

 struct stm32_dmamux {
 	u32 master;
 	u32 request;
 	u32 chan_id;
 };

 struct stm32_dmamux_data {
 	struct dma_router dmarouter;
 	struct clk *clk;
 	void __iomem *iomem;
 	u32 dma_requests; /* Number of DMA requests connected to DMAMUX */
 	u32 dmamux_requests; /* Number of DMA requests routed toward DMAs */
 	spinlock_t lock; /* Protects register access */
 	unsigned long *dma_inuse; /* Used DMA channel */
 	u32 ccr[STM32_DMAMUX_MAX_DMA_REQUESTS]; /* Used to backup CCR register
 						 * in suspend
 						 */
 	u32 dma_reqs[]; /* Number of DMA Request per DMA masters.
 			 *  [0] holds number of DMA Masters.
 			 *  To be kept at very end end of this structure
 			 */
 };

 static inline u32 stm32_dmamux_read(void __iomem *iomem, u32 reg)
 {
 	return readl_relaxed(iomem + reg);
 }

 static inline void stm32_dmamux_write(void __iomem *iomem, u32 reg, u32 val)
 {
 	writel_relaxed(val, iomem + reg);
 }

 static void stm32_dmamux_free(struct device *dev, void *route_data)
 {
 	struct stm32_dmamux_data *dmamux = dev_get_drvdata(dev);
 	struct stm32_dmamux *mux = route_data;
 	unsigned long flags;

 	/* Clear dma request */
 	spin_lock_irqsave(&dmamux->lock, flags);

 	stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id), 0);
 	clear_bit(mux->chan_id, dmamux->dma_inuse);

 	pm_runtime_put_sync(dev);

 	spin_unlock_irqrestore(&dmamux->lock, flags);

 	dev_dbg(dev, "Unmapping DMAMUX(%u) to DMA%u(%u)\n",
 		mux->request, mux->master, mux->chan_id);

 	kfree(mux);
 }

 static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec,
 					 struct of_dma *ofdma)
 {
 	struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
 	struct stm32_dmamux_data *dmamux = platform_get_drvdata(pdev);
 	struct stm32_dmamux *mux;
 	u32 i, min, max;
 	int ret;
 	unsigned long flags;

 	if (dma_spec->args_count != 3) {
 		dev_err(&pdev->dev, "invalid number of dma mux args\n");
 		return ERR_PTR(-EINVAL);
 	}

 	if (dma_spec->args[0] > dmamux->dmamux_requests) {
 		dev_err(&pdev->dev, "invalid mux request number: %d\n",
 			dma_spec->args[0]);
 		return ERR_PTR(-EINVAL);
 	}

 	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
 	if (!mux)
 		return ERR_PTR(-ENOMEM);

 	spin_lock_irqsave(&dmamux->lock, flags);
 	mux->chan_id = find_first_zero_bit(dmamux->dma_inuse,
 					   dmamux->dma_requests);

 	if (mux->chan_id == dmamux->dma_requests) {
 		spin_unlock_irqrestore(&dmamux->lock, flags);
 		dev_err(&pdev->dev, "Run out of free DMA requests\n");
 		ret = -ENOMEM;
 		goto error_chan_id;
 	}
 	set_bit(mux->chan_id, dmamux->dma_inuse);
 	spin_unlock_irqrestore(&dmamux->lock, flags);

 	/* Look for DMA Master */
 	for (i = 1, min = 0, max = dmamux->dma_reqs[i];
 	     i <= dmamux->dma_reqs[0];
 	     min += dmamux->dma_reqs[i], max += dmamux->dma_reqs[++i])
 		if (mux->chan_id < max)
 			break;
 	mux->master = i - 1;

 	/* The of_node_put() will be done in of_dma_router_xlate function */
 	dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", i - 1);
 	if (!dma_spec->np) {
 		dev_err(&pdev->dev, "can't get dma master\n");
 		ret = -EINVAL;
 		goto error;
 	}

 	/* Set dma request */
 	spin_lock_irqsave(&dmamux->lock, flags);
 	ret = pm_runtime_resume_and_get(&pdev->dev);
 	if (ret < 0) {
 		spin_unlock_irqrestore(&dmamux->lock, flags);
 		goto error;
 	}
 	spin_unlock_irqrestore(&dmamux->lock, flags);

 	mux->request = dma_spec->args[0];

 	/*  craft DMA spec */
 	dma_spec->args[3] = dma_spec->args[2];
 	dma_spec->args[2] = dma_spec->args[1];
 	dma_spec->args[1] = 0;
 	dma_spec->args[0] = mux->chan_id - min;
 	dma_spec->args_count = 4;

 	stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id),
 			   mux->request);
 	dev_dbg(&pdev->dev, "Mapping DMAMUX(%u) to DMA%u(%u)\n",
 		mux->request, mux->master, mux->chan_id);

 	return mux;

 error:
 	clear_bit(mux->chan_id, dmamux->dma_inuse);

 error_chan_id:
 	kfree(mux);
 	return ERR_PTR(ret);
 }

 static const struct of_device_id stm32_stm32dma_master_match[] = {
 	{ .compatible = "st,stm32-dma", },
 	{},
 };

 static int stm32_dmamux_probe(struct platform_device *pdev)
 {
 	struct device_node *node = pdev->dev.of_node;
 	const struct of_device_id *match;
 	struct device_node *dma_node;
 	struct stm32_dmamux_data *stm32_dmamux;
 	struct resource *res;
 	void __iomem *iomem;
 	struct reset_control *rst;
 	int i, count, ret;
 	u32 dma_req;

 	if (!node)
 		return -ENODEV;

 	count = device_property_count_u32(&pdev->dev, "dma-masters");
 	if (count < 0) {
 		dev_err(&pdev->dev, "Can't get DMA master(s) node\n");
 		return -ENODEV;
 	}

 	stm32_dmamux = devm_kzalloc(&pdev->dev, sizeof(*stm32_dmamux) +
 				    sizeof(u32) * (count + 1), GFP_KERNEL);
 	if (!stm32_dmamux)
 		return -ENOMEM;

 	dma_req = 0;
 	for (i = 1; i <= count; i++) {
 		dma_node = of_parse_phandle(node, "dma-masters", i - 1);

 		match = of_match_node(stm32_stm32dma_master_match, dma_node);
 		if (!match) {
 			dev_err(&pdev->dev, "DMA master is not supported\n");
 			of_node_put(dma_node);
 			return -EINVAL;
 		}

 		if (of_property_read_u32(dma_node, "dma-requests",
 					 &stm32_dmamux->dma_reqs[i])) {
 			dev_info(&pdev->dev,
 				 "Missing MUX output information, using %u.\n",
 				 STM32_DMAMUX_MAX_DMA_REQUESTS);
 			stm32_dmamux->dma_reqs[i] =
 				STM32_DMAMUX_MAX_DMA_REQUESTS;
 		}
 		dma_req += stm32_dmamux->dma_reqs[i];
 		of_node_put(dma_node);
 	}

 	if (dma_req > STM32_DMAMUX_MAX_DMA_REQUESTS) {
 		dev_err(&pdev->dev, "Too many DMA Master Requests to manage\n");
 		return -ENODEV;
 	}

 	stm32_dmamux->dma_requests = dma_req;
 	stm32_dmamux->dma_reqs[0] = count;
 	stm32_dmamux->dma_inuse = devm_kcalloc(&pdev->dev,
 					       BITS_TO_LONGS(dma_req),
 					       sizeof(unsigned long),
 					       GFP_KERNEL);
 	if (!stm32_dmamux->dma_inuse)
 		return -ENOMEM;

 	if (device_property_read_u32(&pdev->dev, "dma-requests",
 				     &stm32_dmamux->dmamux_requests)) {
 		stm32_dmamux->dmamux_requests = STM32_DMAMUX_MAX_REQUESTS;
 		dev_warn(&pdev->dev, "DMAMUX defaulting on %u requests\n",
 			 stm32_dmamux->dmamux_requests);
 	}
 	pm_runtime_get_noresume(&pdev->dev);

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

 	spin_lock_init(&stm32_dmamux->lock);

 	stm32_dmamux->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(stm32_dmamux->clk))
 		return dev_err_probe(&pdev->dev, PTR_ERR(stm32_dmamux->clk),
 				     "Missing clock controller\n");

 	ret = clk_prepare_enable(stm32_dmamux->clk);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
 		return ret;
 	}

 	rst = devm_reset_control_get(&pdev->dev, NULL);
 	if (IS_ERR(rst)) {
 		ret = PTR_ERR(rst);
 		if (ret == -EPROBE_DEFER)
 			goto err_clk;
 	} else {
 		reset_control_assert(rst);
 		udelay(2);
 		reset_control_deassert(rst);
 	}

 	stm32_dmamux->iomem = iomem;
 	stm32_dmamux->dmarouter.dev = &pdev->dev;
 	stm32_dmamux->dmarouter.route_free = stm32_dmamux_free;

 	platform_set_drvdata(pdev, stm32_dmamux);
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);

 	pm_runtime_get_noresume(&pdev->dev);

 	/* Reset the dmamux */
 	for (i = 0; i < stm32_dmamux->dma_requests; i++)
 		stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i), 0);

 	pm_runtime_put(&pdev->dev);

 	ret = of_dma_router_register(node, stm32_dmamux_route_allocate,
 				     &stm32_dmamux->dmarouter);
 	if (ret)
 		goto pm_disable;

 	return 0;

 pm_disable:
 	pm_runtime_disable(&pdev->dev);
 err_clk:
 	clk_disable_unprepare(stm32_dmamux->clk);

 	return ret;
 }

 #ifdef CONFIG_PM
 static int stm32_dmamux_runtime_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);

 	clk_disable_unprepare(stm32_dmamux->clk);

 	return 0;
 }

 static int stm32_dmamux_runtime_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
 	int ret;

 	ret = clk_prepare_enable(stm32_dmamux->clk);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to prepare_enable clock\n");
 		return ret;
 	}

 	return 0;
 }
 #endif

 #ifdef CONFIG_PM_SLEEP
 static int stm32_dmamux_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
 	int i, ret;

 	ret = pm_runtime_resume_and_get(dev);
 	if (ret < 0)
 		return ret;

 	for (i = 0; i < stm32_dmamux->dma_requests; i++)
 		stm32_dmamux->ccr[i] = stm32_dmamux_read(stm32_dmamux->iomem,
 							 STM32_DMAMUX_CCR(i));

 	pm_runtime_put_sync(dev);

 	pm_runtime_force_suspend(dev);

 	return 0;
 }

 static int stm32_dmamux_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
 	int i, ret;

 	ret = pm_runtime_force_resume(dev);
 	if (ret < 0)
 		return ret;

 	ret = pm_runtime_resume_and_get(dev);
 	if (ret < 0)
 		return ret;

 	for (i = 0; i < stm32_dmamux->dma_requests; i++)
 		stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i),
 				   stm32_dmamux->ccr[i]);

 	pm_runtime_put_sync(dev);

 	return 0;
 }
 #endif

 static const struct dev_pm_ops stm32_dmamux_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(stm32_dmamux_suspend, stm32_dmamux_resume)
 	SET_RUNTIME_PM_OPS(stm32_dmamux_runtime_suspend,
 			   stm32_dmamux_runtime_resume, NULL)
 };

 static const struct of_device_id stm32_dmamux_match[] = {
 	{ .compatible = "st,stm32h7-dmamux" },
 	{},
 };

 static struct platform_driver stm32_dmamux_driver = {
 	.probe	= stm32_dmamux_probe,
 	.driver = {
 		.name = "stm32-dmamux",
 		.of_match_table = stm32_dmamux_match,
 		.pm = &stm32_dmamux_pm_ops,
 	},
 };

 static int __init stm32_dmamux_init(void)
 {
 	return platform_driver_register(&stm32_dmamux_driver);
 }
 arch_initcall(stm32_dmamux_init);

 MODULE_DESCRIPTION("DMA Router driver for STM32 DMA MUX");
 MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
 MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	*
	* Copyright (C) STMicroelectronics SA 2017
	* Author(s): M'boumba Cedric Madianga <cedric.madianga@gmail.com>
	* Pierre-Yves Mordret <pierre-yves.mordret@st.com>
	*
	* DMA Router driver for STM32 DMA MUX
	*
	* Based on TI DMA Crossbar driver
	*/

	#include <linux/clk.h>
	#include <linux/delay.h>
	#include <linux/err.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/of_device.h>
	#include <linux/of_dma.h>
	#include <linux/pm_runtime.h>
	#include <linux/reset.h>
	#include <linux/slab.h>
	#include <linux/spinlock.h>

	#define STM32_DMAMUX_CCR(x) (0x4 * (x))
	#define STM32_DMAMUX_MAX_DMA_REQUESTS 32
	#define STM32_DMAMUX_MAX_REQUESTS 255

	struct stm32_dmamux {
	u32 master;
	u32 request;
	u32 chan_id;
	};

	struct stm32_dmamux_data {
	struct dma_router dmarouter;
	struct clk *clk;
	void __iomem *iomem;
	u32 dma_requests; /* Number of DMA requests connected to DMAMUX */
	u32 dmamux_requests; /* Number of DMA requests routed toward DMAs */
	spinlock_t lock; /* Protects register access */
	unsigned long dma_inuse; / Used DMA channel */
	u32 ccr[STM32_DMAMUX_MAX_DMA_REQUESTS]; /* Used to backup CCR register
	* in suspend
	*/
	u32 dma_reqs[]; /* Number of DMA Request per DMA masters.
	* [0] holds number of DMA Masters.
	* To be kept at very end end of this structure
	*/
	};

	static inline u32 stm32_dmamux_read(void __iomem *iomem, u32 reg)
	{
	return readl_relaxed(iomem + reg);
	}

	static inline void stm32_dmamux_write(void __iomem *iomem, u32 reg, u32 val)
	{
	writel_relaxed(val, iomem + reg);
	}

	static void stm32_dmamux_free(struct device dev, void route_data)
	{
	struct stm32_dmamux_data *dmamux = dev_get_drvdata(dev);
	struct stm32_dmamux *mux = route_data;
	unsigned long flags;

	/* Clear dma request */
	spin_lock_irqsave(&dmamux->lock, flags);

	stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id), 0);
	clear_bit(mux->chan_id, dmamux->dma_inuse);

	pm_runtime_put_sync(dev);

	spin_unlock_irqrestore(&dmamux->lock, flags);

	dev_dbg(dev, "Unmapping DMAMUX(%u) to DMA%u(%u)\n",
	mux->request, mux->master, mux->chan_id);

	kfree(mux);
	}

	static void stm32_dmamux_route_allocate(struct of_phandle_args dma_spec,
	struct of_dma *ofdma)
	{
	struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
	struct stm32_dmamux_data *dmamux = platform_get_drvdata(pdev);
	struct stm32_dmamux *mux;
	u32 i, min, max;
	int ret;
	unsigned long flags;

	if (dma_spec->args_count != 3) {
	dev_err(&pdev->dev, "invalid number of dma mux args\n");
	return ERR_PTR(-EINVAL);
	}

	if (dma_spec->args[0] > dmamux->dmamux_requests) {
	dev_err(&pdev->dev, "invalid mux request number: %d\n",
	dma_spec->args[0]);
	return ERR_PTR(-EINVAL);
	}

	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
	if (!mux)
	return ERR_PTR(-ENOMEM);

	spin_lock_irqsave(&dmamux->lock, flags);
	mux->chan_id = find_first_zero_bit(dmamux->dma_inuse,
	dmamux->dma_requests);

	if (mux->chan_id == dmamux->dma_requests) {
	spin_unlock_irqrestore(&dmamux->lock, flags);
	dev_err(&pdev->dev, "Run out of free DMA requests\n");
	ret = -ENOMEM;
	goto error_chan_id;
	}
	set_bit(mux->chan_id, dmamux->dma_inuse);
	spin_unlock_irqrestore(&dmamux->lock, flags);

	/* Look for DMA Master */
	for (i = 1, min = 0, max = dmamux->dma_reqs[i];
	i <= dmamux->dma_reqs[0];
	min += dmamux->dma_reqs[i], max += dmamux->dma_reqs[++i])
	if (mux->chan_id < max)
	break;
	mux->master = i - 1;

	/* The of_node_put() will be done in of_dma_router_xlate function */
	dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", i - 1);
	if (!dma_spec->np) {
	dev_err(&pdev->dev, "can't get dma master\n");
	ret = -EINVAL;
	goto error;
	}

	/* Set dma request */
	spin_lock_irqsave(&dmamux->lock, flags);
	ret = pm_runtime_resume_and_get(&pdev->dev);
	if (ret < 0) {
	spin_unlock_irqrestore(&dmamux->lock, flags);
	goto error;
	}
	spin_unlock_irqrestore(&dmamux->lock, flags);

	mux->request = dma_spec->args[0];

	/* craft DMA spec */
	dma_spec->args[3] = dma_spec->args[2];
	dma_spec->args[2] = dma_spec->args[1];
	dma_spec->args[1] = 0;
	dma_spec->args[0] = mux->chan_id - min;
	dma_spec->args_count = 4;

	stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id),
	mux->request);
	dev_dbg(&pdev->dev, "Mapping DMAMUX(%u) to DMA%u(%u)\n",
	mux->request, mux->master, mux->chan_id);

	return mux;

	error:
	clear_bit(mux->chan_id, dmamux->dma_inuse);

	error_chan_id:
	kfree(mux);
	return ERR_PTR(ret);
	}

	static const struct of_device_id stm32_stm32dma_master_match[] = {
	{ .compatible = "st,stm32-dma", },
	{},
	};

	static int stm32_dmamux_probe(struct platform_device *pdev)
	{
	struct device_node *node = pdev->dev.of_node;
	const struct of_device_id *match;
	struct device_node *dma_node;
	struct stm32_dmamux_data *stm32_dmamux;
	struct resource *res;
	void __iomem *iomem;
	struct reset_control *rst;
	int i, count, ret;
	u32 dma_req;

	if (!node)
	return -ENODEV;

	count = device_property_count_u32(&pdev->dev, "dma-masters");
	if (count < 0) {
	dev_err(&pdev->dev, "Can't get DMA master(s) node\n");
	return -ENODEV;
	}

	stm32_dmamux = devm_kzalloc(&pdev->dev, sizeof(*stm32_dmamux) +
	sizeof(u32) * (count + 1), GFP_KERNEL);
	if (!stm32_dmamux)
	return -ENOMEM;

	dma_req = 0;
	for (i = 1; i <= count; i++) {
	dma_node = of_parse_phandle(node, "dma-masters", i - 1);

	match = of_match_node(stm32_stm32dma_master_match, dma_node);
	if (!match) {
	dev_err(&pdev->dev, "DMA master is not supported\n");
	of_node_put(dma_node);
	return -EINVAL;
	}

	if (of_property_read_u32(dma_node, "dma-requests",
	&stm32_dmamux->dma_reqs[i])) {
	dev_info(&pdev->dev,
	"Missing MUX output information, using %u.\n",
	STM32_DMAMUX_MAX_DMA_REQUESTS);
	stm32_dmamux->dma_reqs[i] =
	STM32_DMAMUX_MAX_DMA_REQUESTS;
	}
	dma_req += stm32_dmamux->dma_reqs[i];
	of_node_put(dma_node);
	}

	if (dma_req > STM32_DMAMUX_MAX_DMA_REQUESTS) {
	dev_err(&pdev->dev, "Too many DMA Master Requests to manage\n");
	return -ENODEV;
	}

	stm32_dmamux->dma_requests = dma_req;
	stm32_dmamux->dma_reqs[0] = count;
	stm32_dmamux->dma_inuse = devm_kcalloc(&pdev->dev,
	BITS_TO_LONGS(dma_req),
	sizeof(unsigned long),
	GFP_KERNEL);
	if (!stm32_dmamux->dma_inuse)
	return -ENOMEM;

	if (device_property_read_u32(&pdev->dev, "dma-requests",
	&stm32_dmamux->dmamux_requests)) {
	stm32_dmamux->dmamux_requests = STM32_DMAMUX_MAX_REQUESTS;
	dev_warn(&pdev->dev, "DMAMUX defaulting on %u requests\n",
	stm32_dmamux->dmamux_requests);
	}
	pm_runtime_get_noresume(&pdev->dev);

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

	spin_lock_init(&stm32_dmamux->lock);

	stm32_dmamux->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(stm32_dmamux->clk))
	return dev_err_probe(&pdev->dev, PTR_ERR(stm32_dmamux->clk),
	"Missing clock controller\n");

	ret = clk_prepare_enable(stm32_dmamux->clk);
	if (ret < 0) {
	dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
	return ret;
	}

	rst = devm_reset_control_get(&pdev->dev, NULL);
	if (IS_ERR(rst)) {
	ret = PTR_ERR(rst);
	if (ret == -EPROBE_DEFER)
	goto err_clk;
	} else {
	reset_control_assert(rst);
	udelay(2);
	reset_control_deassert(rst);
	}

	stm32_dmamux->iomem = iomem;
	stm32_dmamux->dmarouter.dev = &pdev->dev;
	stm32_dmamux->dmarouter.route_free = stm32_dmamux_free;

	platform_set_drvdata(pdev, stm32_dmamux);
	pm_runtime_set_active(&pdev->dev);
	pm_runtime_enable(&pdev->dev);

	pm_runtime_get_noresume(&pdev->dev);

	/* Reset the dmamux */
	for (i = 0; i < stm32_dmamux->dma_requests; i++)
	stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i), 0);

	pm_runtime_put(&pdev->dev);

	ret = of_dma_router_register(node, stm32_dmamux_route_allocate,
	&stm32_dmamux->dmarouter);
	if (ret)
	goto pm_disable;

	return 0;

	pm_disable:
	pm_runtime_disable(&pdev->dev);
	err_clk:
	clk_disable_unprepare(stm32_dmamux->clk);

	return ret;
	}

	#ifdef CONFIG_PM
	static int stm32_dmamux_runtime_suspend(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);

	clk_disable_unprepare(stm32_dmamux->clk);

	return 0;
	}

	static int stm32_dmamux_runtime_resume(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
	int ret;

	ret = clk_prepare_enable(stm32_dmamux->clk);
	if (ret) {
	dev_err(&pdev->dev, "failed to prepare_enable clock\n");
	return ret;
	}

	return 0;
	}
	#endif

	#ifdef CONFIG_PM_SLEEP
	static int stm32_dmamux_suspend(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
	int i, ret;

	ret = pm_runtime_resume_and_get(dev);
	if (ret < 0)
	return ret;

	for (i = 0; i < stm32_dmamux->dma_requests; i++)
	stm32_dmamux->ccr[i] = stm32_dmamux_read(stm32_dmamux->iomem,
	STM32_DMAMUX_CCR(i));

	pm_runtime_put_sync(dev);

	pm_runtime_force_suspend(dev);

	return 0;
	}

	static int stm32_dmamux_resume(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
	int i, ret;

	ret = pm_runtime_force_resume(dev);
	if (ret < 0)
	return ret;

	ret = pm_runtime_resume_and_get(dev);
	if (ret < 0)
	return ret;

	for (i = 0; i < stm32_dmamux->dma_requests; i++)
	stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i),
	stm32_dmamux->ccr[i]);

	pm_runtime_put_sync(dev);

	return 0;
	}
	#endif

	static const struct dev_pm_ops stm32_dmamux_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(stm32_dmamux_suspend, stm32_dmamux_resume)
	SET_RUNTIME_PM_OPS(stm32_dmamux_runtime_suspend,
	stm32_dmamux_runtime_resume, NULL)
	};

	static const struct of_device_id stm32_dmamux_match[] = {
	{ .compatible = "st,stm32h7-dmamux" },
	{},
	};

	static struct platform_driver stm32_dmamux_driver = {
	.probe = stm32_dmamux_probe,
	.driver = {
	.name = "stm32-dmamux",
	.of_match_table = stm32_dmamux_match,
	.pm = &stm32_dmamux_pm_ops,
	},
	};

	static int __init stm32_dmamux_init(void)
	{
	return platform_driver_register(&stm32_dmamux_driver);
	}
	arch_initcall(stm32_dmamux_init);

	MODULE_DESCRIPTION("DMA Router driver for STM32 DMA MUX");
	MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
	MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
	MODULE_LICENSE("GPL v2");