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linux/drivers/iio/adc/imx8qxp-adc.c 

// SPDX-License-Identifier: GPL-2.0+
/*
 * NXP i.MX8QXP ADC driver
 *
 * Based on the work of Haibo Chen <[email protected]>
 * The initial developer of the original code is Haibo Chen.
 * Portions created by Haibo Chen are Copyright (C) 2018 NXP.
 * All Rights Reserved.
 *
 * Copyright (C) 2018 NXP
 * Copyright (C) 2021 Cai Huoqing
 */
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>

#include <linux/iio/iio.h>

#define ADC_DRIVER_NAME		"imx8qxp-adc"

/* Register map definition */
#define IMX8QXP_ADR_ADC_CTRL		0x10
#define IMX8QXP_ADR_ADC_STAT		0x14
#define IMX8QXP_ADR_ADC_IE		0x18
#define IMX8QXP_ADR_ADC_DE		0x1c
#define IMX8QXP_ADR_ADC_CFG		0x20
#define IMX8QXP_ADR_ADC_FCTRL		0x30
#define IMX8QXP_ADR_ADC_SWTRIG		0x34
#define IMX8QXP_ADR_ADC_TCTRL(tid)	(0xc0 + (tid) * 4)
#define IMX8QXP_ADR_ADC_CMDL(cid)	(0x100 + (cid) * 8)
#define IMX8QXP_ADR_ADC_CMDH(cid)	(0x104 + (cid) * 8)
#define IMX8QXP_ADR_ADC_RESFIFO		0x300
#define IMX8QXP_ADR_ADC_TST		0xffc

/* ADC bit shift */
#define IMX8QXP_ADC_IE_FWMIE_MASK		GENMASK(1, 0)
#define IMX8QXP_ADC_CTRL_FIFO_RESET_MASK	BIT(8)
#define IMX8QXP_ADC_CTRL_SOFTWARE_RESET_MASK	BIT(1)
#define IMX8QXP_ADC_CTRL_ADC_EN_MASK		BIT(0)
#define IMX8QXP_ADC_TCTRL_TCMD_MASK		GENMASK(31, 24)
#define IMX8QXP_ADC_TCTRL_TDLY_MASK		GENMASK(23, 16)
#define IMX8QXP_ADC_TCTRL_TPRI_MASK		GENMASK(15, 8)
#define IMX8QXP_ADC_TCTRL_HTEN_MASK		GENMASK(7, 0)
#define IMX8QXP_ADC_CMDL_CSCALE_MASK		GENMASK(13, 8)
#define IMX8QXP_ADC_CMDL_MODE_MASK		BIT(7)
#define IMX8QXP_ADC_CMDL_DIFF_MASK		BIT(6)
#define IMX8QXP_ADC_CMDL_ABSEL_MASK		BIT(5)
#define IMX8QXP_ADC_CMDL_ADCH_MASK		GENMASK(2, 0)
#define IMX8QXP_ADC_CMDH_NEXT_MASK		GENMASK(31, 24)
#define IMX8QXP_ADC_CMDH_LOOP_MASK		GENMASK(23, 16)
#define IMX8QXP_ADC_CMDH_AVGS_MASK		GENMASK(15, 12)
#define IMX8QXP_ADC_CMDH_STS_MASK		BIT(8)
#define IMX8QXP_ADC_CMDH_LWI_MASK		GENMASK(7, 7)
#define IMX8QXP_ADC_CMDH_CMPEN_MASK		GENMASK(0, 0)
#define IMX8QXP_ADC_CFG_PWREN_MASK		BIT(28)
#define IMX8QXP_ADC_CFG_PUDLY_MASK		GENMASK(23, 16)
#define IMX8QXP_ADC_CFG_REFSEL_MASK		GENMASK(7, 6)
#define IMX8QXP_ADC_CFG_PWRSEL_MASK		GENMASK(5, 4)
#define IMX8QXP_ADC_CFG_TPRICTRL_MASK		GENMASK(3, 0)
#define IMX8QXP_ADC_FCTRL_FWMARK_MASK		GENMASK(20, 16)
#define IMX8QXP_ADC_FCTRL_FCOUNT_MASK		GENMASK(4, 0)
#define IMX8QXP_ADC_RESFIFO_VAL_MASK		GENMASK(18, 3)

/* ADC PARAMETER*/
#define IMX8QXP_ADC_CMDL_CHANNEL_SCALE_FULL		GENMASK(5, 0)
#define IMX8QXP_ADC_CMDL_SEL_A_A_B_CHANNEL		0
#define IMX8QXP_ADC_CMDL_STANDARD_RESOLUTION		0
#define IMX8QXP_ADC_CMDL_MODE_SINGLE			0
#define IMX8QXP_ADC_CMDH_LWI_INCREMENT_DIS		0
#define IMX8QXP_ADC_CMDH_CMPEN_DIS			0
#define IMX8QXP_ADC_PAUSE_EN				BIT(31)
#define IMX8QXP_ADC_TCTRL_TPRI_PRIORITY_HIGH		0

#define IMX8QXP_ADC_TCTRL_HTEN_HW_TIRG_DIS		0

#define IMX8QXP_ADC_TIMEOUT		msecs_to_jiffies(100)

#define IMX8QXP_ADC_MAX_FIFO_SIZE		16

struct imx8qxp_adc {
	struct device *dev;
	void __iomem *regs;
	struct clk *clk;
	struct clk *ipg_clk;
	struct regulator *vref;
	/* Serialise ADC channel reads */
	struct mutex lock;
	struct completion completion;
	u32 fifo[IMX8QXP_ADC_MAX_FIFO_SIZE];
};

#define IMX8QXP_ADC_CHAN(_idx) {				\
	.type = IIO_VOLTAGE,					\
	.indexed = 1,						\
	.channel = (_idx),					\
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |	\
				BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
}

static const struct iio_chan_spec imx8qxp_adc_iio_channels[] = {
	IMX8QXP_ADC_CHAN(0),
	IMX8QXP_ADC_CHAN(1),
	IMX8QXP_ADC_CHAN(2),
	IMX8QXP_ADC_CHAN(3),
	IMX8QXP_ADC_CHAN(4),
	IMX8QXP_ADC_CHAN(5),
	IMX8QXP_ADC_CHAN(6),
	IMX8QXP_ADC_CHAN(7),
};

static void imx8qxp_adc_reset(struct imx8qxp_adc *adc)
{
	u32 ctrl;

	/*software reset, need to clear the set bit*/
	ctrl = readl(adc->regs + IMX8QXP_ADR_ADC_CTRL);
	ctrl |= FIELD_PREP(IMX8QXP_ADC_CTRL_SOFTWARE_RESET_MASK, 1);
	writel(ctrl, adc->regs + IMX8QXP_ADR_ADC_CTRL);
	udelay(10);
	ctrl &= ~FIELD_PREP(IMX8QXP_ADC_CTRL_SOFTWARE_RESET_MASK, 1);
	writel(ctrl, adc->regs + IMX8QXP_ADR_ADC_CTRL);

	/* reset the fifo */
	ctrl |= FIELD_PREP(IMX8QXP_ADC_CTRL_FIFO_RESET_MASK, 1);
	writel(ctrl, adc->regs + IMX8QXP_ADR_ADC_CTRL);
}

static void imx8qxp_adc_reg_config(struct imx8qxp_adc *adc, int channel)
{
	u32 adc_cfg, adc_tctrl, adc_cmdl, adc_cmdh;

	/* ADC configuration */
	adc_cfg = FIELD_PREP(IMX8QXP_ADC_CFG_PWREN_MASK, 1) |
		  FIELD_PREP(IMX8QXP_ADC_CFG_PUDLY_MASK, 0x80)|
		  FIELD_PREP(IMX8QXP_ADC_CFG_REFSEL_MASK, 0) |
		  FIELD_PREP(IMX8QXP_ADC_CFG_PWRSEL_MASK, 3) |
		  FIELD_PREP(IMX8QXP_ADC_CFG_TPRICTRL_MASK, 0);
	writel(adc_cfg, adc->regs + IMX8QXP_ADR_ADC_CFG);

	/* config the trigger control */
	adc_tctrl = FIELD_PREP(IMX8QXP_ADC_TCTRL_TCMD_MASK, 1) |
		    FIELD_PREP(IMX8QXP_ADC_TCTRL_TDLY_MASK, 0) |
		    FIELD_PREP(IMX8QXP_ADC_TCTRL_TPRI_MASK, IMX8QXP_ADC_TCTRL_TPRI_PRIORITY_HIGH) |
		    FIELD_PREP(IMX8QXP_ADC_TCTRL_HTEN_MASK, IMX8QXP_ADC_TCTRL_HTEN_HW_TIRG_DIS);
	writel(adc_tctrl, adc->regs + IMX8QXP_ADR_ADC_TCTRL(0));

	/* config the cmd */
	adc_cmdl = FIELD_PREP(IMX8QXP_ADC_CMDL_CSCALE_MASK, IMX8QXP_ADC_CMDL_CHANNEL_SCALE_FULL) |
		   FIELD_PREP(IMX8QXP_ADC_CMDL_MODE_MASK, IMX8QXP_ADC_CMDL_STANDARD_RESOLUTION) |
		   FIELD_PREP(IMX8QXP_ADC_CMDL_DIFF_MASK, IMX8QXP_ADC_CMDL_MODE_SINGLE) |
		   FIELD_PREP(IMX8QXP_ADC_CMDL_ABSEL_MASK, IMX8QXP_ADC_CMDL_SEL_A_A_B_CHANNEL) |
		   FIELD_PREP(IMX8QXP_ADC_CMDL_ADCH_MASK, channel);
	writel(adc_cmdl, adc->regs + IMX8QXP_ADR_ADC_CMDL(0));

	adc_cmdh = FIELD_PREP(IMX8QXP_ADC_CMDH_NEXT_MASK, 0) |
		   FIELD_PREP(IMX8QXP_ADC_CMDH_LOOP_MASK, 0) |
		   FIELD_PREP(IMX8QXP_ADC_CMDH_AVGS_MASK, 7) |
		   FIELD_PREP(IMX8QXP_ADC_CMDH_STS_MASK, 0) |
		   FIELD_PREP(IMX8QXP_ADC_CMDH_LWI_MASK, IMX8QXP_ADC_CMDH_LWI_INCREMENT_DIS) |
		   FIELD_PREP(IMX8QXP_ADC_CMDH_CMPEN_MASK, IMX8QXP_ADC_CMDH_CMPEN_DIS);
	writel(adc_cmdh, adc->regs + IMX8QXP_ADR_ADC_CMDH(0));
}

static void imx8qxp_adc_fifo_config(struct imx8qxp_adc *adc)
{
	u32 fifo_ctrl, interrupt_en;

	fifo_ctrl = readl(adc->regs + IMX8QXP_ADR_ADC_FCTRL);
	fifo_ctrl &= ~IMX8QXP_ADC_FCTRL_FWMARK_MASK;
	/* set the watermark level to 1 */
	fifo_ctrl |= FIELD_PREP(IMX8QXP_ADC_FCTRL_FWMARK_MASK, 0);
	writel(fifo_ctrl, adc->regs + IMX8QXP_ADR_ADC_FCTRL);

	/* FIFO Watermark Interrupt Enable */
	interrupt_en = readl(adc->regs + IMX8QXP_ADR_ADC_IE);
	interrupt_en |= FIELD_PREP(IMX8QXP_ADC_IE_FWMIE_MASK, 1);
	writel(interrupt_en, adc->regs + IMX8QXP_ADR_ADC_IE);
}

static void imx8qxp_adc_disable(struct imx8qxp_adc *adc)
{
	u32 ctrl;

	ctrl = readl(adc->regs + IMX8QXP_ADR_ADC_CTRL);
	ctrl &= ~FIELD_PREP(IMX8QXP_ADC_CTRL_ADC_EN_MASK, 1);
	writel(ctrl, adc->regs + IMX8QXP_ADR_ADC_CTRL);
}

static int imx8qxp_adc_read_raw(struct iio_dev *indio_dev,
				struct iio_chan_spec const *chan,
				int *val, int *val2, long mask)
{
	struct imx8qxp_adc *adc = iio_priv(indio_dev);
	struct device *dev = adc->dev;

	u32 ctrl;
	long ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		pm_runtime_get_sync(dev);

		mutex_lock(&adc->lock);
		reinit_completion(&adc->completion);

		imx8qxp_adc_reg_config(adc, chan->channel);

		imx8qxp_adc_fifo_config(adc);

		/* adc enable */
		ctrl = readl(adc->regs + IMX8QXP_ADR_ADC_CTRL);
		ctrl |= FIELD_PREP(IMX8QXP_ADC_CTRL_ADC_EN_MASK, 1);
		writel(ctrl, adc->regs + IMX8QXP_ADR_ADC_CTRL);
		/* adc start */
		writel(1, adc->regs + IMX8QXP_ADR_ADC_SWTRIG);

		ret = wait_for_completion_interruptible_timeout(&adc->completion,
								IMX8QXP_ADC_TIMEOUT);

		pm_runtime_mark_last_busy(dev);
		pm_runtime_put_sync_autosuspend(dev);

		if (ret == 0) {
			mutex_unlock(&adc->lock);
			return -ETIMEDOUT;
		}
		if (ret < 0) {
			mutex_unlock(&adc->lock);
			return ret;
		}

		*val = adc->fifo[0];

		mutex_unlock(&adc->lock);
		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:
		ret = regulator_get_voltage(adc->vref);
		if (ret < 0)
			return ret;
		*val = ret / 1000;
		*val2 = 12;
		return IIO_VAL_FRACTIONAL_LOG2;

	case IIO_CHAN_INFO_SAMP_FREQ:
		*val = clk_get_rate(adc->clk) / 3;
		return IIO_VAL_INT;

	default:
		return -EINVAL;
	}
}

static irqreturn_t imx8qxp_adc_isr(int irq, void *dev_id)
{
	struct imx8qxp_adc *adc = dev_id;
	u32 fifo_count;
	int i;

	fifo_count = FIELD_GET(IMX8QXP_ADC_FCTRL_FCOUNT_MASK,
			       readl(adc->regs + IMX8QXP_ADR_ADC_FCTRL));

	for (i = 0; i < fifo_count; i++)
		adc->fifo[i] = FIELD_GET(IMX8QXP_ADC_RESFIFO_VAL_MASK,
				readl_relaxed(adc->regs + IMX8QXP_ADR_ADC_RESFIFO));

	if (fifo_count)
		complete(&adc->completion);

	return IRQ_HANDLED;
}

static int imx8qxp_adc_reg_access(struct iio_dev *indio_dev, unsigned int reg,
				  unsigned int writeval, unsigned int *readval)
{
	struct imx8qxp_adc *adc = iio_priv(indio_dev);
	struct device *dev = adc->dev;

	if (!readval || reg % 4 || reg > IMX8QXP_ADR_ADC_TST)
		return -EINVAL;

	pm_runtime_get_sync(dev);

	*readval = readl(adc->regs + reg);

	pm_runtime_mark_last_busy(dev);
	pm_runtime_put_sync_autosuspend(dev);

	return 0;
}

static const struct iio_info imx8qxp_adc_iio_info = {
	.read_raw = &imx8qxp_adc_read_raw,
	.debugfs_reg_access = &imx8qxp_adc_reg_access,
};

static int imx8qxp_adc_probe(struct platform_device *pdev)
{
	struct imx8qxp_adc *adc;
	struct iio_dev *indio_dev;
	struct device *dev = &pdev->dev;
	int irq;
	int ret;

	indio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
	if (!indio_dev) {
		dev_err(dev, "Failed allocating iio device\n");
		return -ENOMEM;
	}

	adc = iio_priv(indio_dev);
	adc->dev = dev;

	mutex_init(&adc->lock);
	adc->regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(adc->regs))
		return PTR_ERR(adc->regs);

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

	adc->clk = devm_clk_get(dev, "per");
	if (IS_ERR(adc->clk))
		return dev_err_probe(dev, PTR_ERR(adc->clk), "Failed getting clock\n");

	adc->ipg_clk = devm_clk_get(dev, "ipg");
	if (IS_ERR(adc->ipg_clk))
		return dev_err_probe(dev, PTR_ERR(adc->ipg_clk), "Failed getting clock\n");

	adc->vref = devm_regulator_get(dev, "vref");
	if (IS_ERR(adc->vref))
		return dev_err_probe(dev, PTR_ERR(adc->vref), "Failed getting reference voltage\n");

	ret = regulator_enable(adc->vref);
	if (ret) {
		dev_err(dev, "Can't enable adc reference top voltage\n");
		return ret;
	}

	platform_set_drvdata(pdev, indio_dev);

	init_completion(&adc->completion);

	indio_dev->name = ADC_DRIVER_NAME;
	indio_dev->info = &imx8qxp_adc_iio_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = imx8qxp_adc_iio_channels;
	indio_dev->num_channels = ARRAY_SIZE(imx8qxp_adc_iio_channels);

	ret = clk_prepare_enable(adc->clk);
	if (ret) {
		dev_err(&pdev->dev, "Could not prepare or enable the clock.\n");
		goto error_regulator_disable;
	}

	ret = clk_prepare_enable(adc->ipg_clk);
	if (ret) {
		dev_err(&pdev->dev, "Could not prepare or enable the clock.\n");
		goto error_adc_clk_disable;
	}

	ret = devm_request_irq(dev, irq, imx8qxp_adc_isr, 0, ADC_DRIVER_NAME, adc);
	if (ret < 0) {
		dev_err(dev, "Failed requesting irq, irq = %d\n", irq);
		goto error_ipg_clk_disable;
	}

	imx8qxp_adc_reset(adc);

	ret = iio_device_register(indio_dev);
	if (ret) {
		imx8qxp_adc_disable(adc);
		dev_err(dev, "Couldn't register the device.\n");
		goto error_ipg_clk_disable;
	}

	pm_runtime_set_active(dev);
	pm_runtime_set_autosuspend_delay(dev, 50);
	pm_runtime_use_autosuspend(dev);
	pm_runtime_enable(dev);

	return 0;

error_ipg_clk_disable:
	clk_disable_unprepare(adc->ipg_clk);
error_adc_clk_disable:
	clk_disable_unprepare(adc->clk);
error_regulator_disable:
	regulator_disable(adc->vref);

	return ret;
}

static void imx8qxp_adc_remove(struct platform_device *pdev)
{
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
	struct imx8qxp_adc *adc = iio_priv(indio_dev);
	struct device *dev = adc->dev;

	pm_runtime_get_sync(dev);

	iio_device_unregister(indio_dev);

	imx8qxp_adc_disable(adc);

	clk_disable_unprepare(adc->clk);
	clk_disable_unprepare(adc->ipg_clk);
	regulator_disable(adc->vref);

	pm_runtime_disable(dev);
	pm_runtime_put_noidle(dev);
}

static int imx8qxp_adc_runtime_suspend(struct device *dev)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct imx8qxp_adc *adc = iio_priv(indio_dev);

	imx8qxp_adc_disable(adc);

	clk_disable_unprepare(adc->clk);
	clk_disable_unprepare(adc->ipg_clk);
	regulator_disable(adc->vref);

	return 0;
}

static int imx8qxp_adc_runtime_resume(struct device *dev)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct imx8qxp_adc *adc = iio_priv(indio_dev);
	int ret;

	ret = regulator_enable(adc->vref);
	if (ret) {
		dev_err(dev, "Can't enable adc reference top voltage, err = %d\n", ret);
		return ret;
	}

	ret = clk_prepare_enable(adc->clk);
	if (ret) {
		dev_err(dev, "Could not prepare or enable clock.\n");
		goto err_disable_reg;
	}

	ret = clk_prepare_enable(adc->ipg_clk);
	if (ret) {
		dev_err(dev, "Could not prepare or enable clock.\n");
		goto err_unprepare_clk;
	}

	imx8qxp_adc_reset(adc);

	return 0;

err_unprepare_clk:
	clk_disable_unprepare(adc->clk);

err_disable_reg:
	regulator_disable(adc->vref);

	return ret;
}

static DEFINE_RUNTIME_DEV_PM_OPS(imx8qxp_adc_pm_ops,
				 imx8qxp_adc_runtime_suspend,
				 imx8qxp_adc_runtime_resume, NULL);

static const struct of_device_id imx8qxp_adc_match[] = {
	{ .compatible = "nxp,imx8qxp-adc", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx8qxp_adc_match);

static struct platform_driver imx8qxp_adc_driver = {
	.probe		= imx8qxp_adc_probe,
	.remove_new	= imx8qxp_adc_remove,
	.driver		= {
		.name	= ADC_DRIVER_NAME,
		.of_match_table = imx8qxp_adc_match,
		.pm	= pm_ptr(&imx8qxp_adc_pm_ops),
	},
};

module_platform_driver(imx8qxp_adc_driver);

MODULE_DESCRIPTION("i.MX8QuadXPlus ADC driver");
MODULE_LICENSE("GPL v2");