drivers/iio/adc/ti_am335x_adc.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * TI ADC MFD driver
  *
  * Copyright (C) 2012 Texas Instruments Incorporated - https://www.ti.com/
  */

 #include <linux/kernel.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/iio/iio.h>
 #include <linux/of.h>
 #include <linux/iio/machine.h>
 #include <linux/iio/driver.h>
 #include <linux/iopoll.h>

 #include <linux/mfd/ti_am335x_tscadc.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/kfifo_buf.h>

 #include <linux/dmaengine.h>
 #include <linux/dma-mapping.h>

 #define DMA_BUFFER_SIZE		SZ_2K

 struct tiadc_dma {
 	struct dma_slave_config	conf;
 	struct dma_chan		*chan;
 	dma_addr_t		addr;
 	dma_cookie_t		cookie;
 	u8			*buf;
 	int			current_period;
 	int			period_size;
 	u8			fifo_thresh;
 };

 struct tiadc_device {
 	struct ti_tscadc_dev *mfd_tscadc;
 	struct tiadc_dma dma;
 	struct mutex fifo1_lock; /* to protect fifo access */
 	int channels;
 	int total_ch_enabled;
 	u8 channel_line[8];
 	u8 channel_step[8];
 	int buffer_en_ch_steps;
 	u16 data[8];
 	u32 open_delay[8], sample_delay[8], step_avg[8];
 };

 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
 {
 	return readl(adc->mfd_tscadc->tscadc_base + reg);
 }

 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
 			 unsigned int val)
 {
 	writel(val, adc->mfd_tscadc->tscadc_base + reg);
 }

 static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
 {
 	u32 step_en;

 	step_en = ((1 << adc_dev->channels) - 1);
 	step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
 	return step_en;
 }

 static u32 get_adc_chan_step_mask(struct tiadc_device *adc_dev,
 				  struct iio_chan_spec const *chan)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
 		if (chan->channel == adc_dev->channel_line[i]) {
 			u32 step;

 			step = adc_dev->channel_step[i];
 			/* +1 for the charger */
 			return 1 << (step + 1);
 		}
 	}
 	WARN_ON(1);
 	return 0;
 }

 static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
 {
 	return 1 << adc_dev->channel_step[chan];
 }

 static int tiadc_wait_idle(struct tiadc_device *adc_dev)
 {
 	u32 val;

 	return readl_poll_timeout(adc_dev->mfd_tscadc->tscadc_base + REG_ADCFSM,
 				  val, !(val & SEQ_STATUS), 10,
 				  IDLE_TIMEOUT_MS * 1000 * adc_dev->channels);
 }

 static void tiadc_step_config(struct iio_dev *indio_dev)
 {
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	unsigned int stepconfig;
 	int i, steps = 0;

 	/*
 	 * There are 16 configurable steps and 8 analog input
 	 * lines available which are shared between Touchscreen and ADC.
 	 *
 	 * Steps forwards i.e. from 0 towards 16 are used by ADC
 	 * depending on number of input lines needed.
 	 * Channel would represent which analog input
 	 * needs to be given to ADC to digitalize data.
 	 */
 	for (i = 0; i < adc_dev->channels; i++) {
 		int chan;

 		chan = adc_dev->channel_line[i];

 		if (adc_dev->step_avg[i])
 			stepconfig = STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) |
 				     STEPCONFIG_FIFO1;
 		else
 			stepconfig = STEPCONFIG_FIFO1;

 		if (iio_buffer_enabled(indio_dev))
 			stepconfig |= STEPCONFIG_MODE_SWCNT;

 		tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
 			     stepconfig | STEPCONFIG_INP(chan) |
 			     STEPCONFIG_INM_ADCREFM | STEPCONFIG_RFP_VREFP |
 			     STEPCONFIG_RFM_VREFN);

 		tiadc_writel(adc_dev, REG_STEPDELAY(steps),
 			     STEPDELAY_OPEN(adc_dev->open_delay[i]) |
 			     STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));

 		adc_dev->channel_step[i] = steps;
 		steps++;
 	}
 }

 static irqreturn_t tiadc_irq_h(int irq, void *private)
 {
 	struct iio_dev *indio_dev = private;
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	unsigned int status, config, adc_fsm;
 	unsigned short count = 0;

 	status = tiadc_readl(adc_dev, REG_IRQSTATUS);

 	/*
 	 * ADC and touchscreen share the IRQ line.
 	 * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
 	 */
 	if (status & IRQENB_FIFO1OVRRUN) {
 		/* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
 		config = tiadc_readl(adc_dev, REG_CTRL);
 		config &= ~(CNTRLREG_SSENB);
 		tiadc_writel(adc_dev, REG_CTRL, config);
 		tiadc_writel(adc_dev, REG_IRQSTATUS,
 			     IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW |
 			     IRQENB_FIFO1THRES);

 		/*
 		 * Wait for the idle state.
 		 * ADC needs to finish the current conversion
 		 * before disabling the module
 		 */
 		do {
 			adc_fsm = tiadc_readl(adc_dev, REG_ADCFSM);
 		} while (adc_fsm != 0x10 && count++ < 100);

 		tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_SSENB));
 		return IRQ_HANDLED;
 	} else if (status & IRQENB_FIFO1THRES) {
 		/* Disable irq and wake worker thread */
 		tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
 		return IRQ_WAKE_THREAD;
 	}

 	return IRQ_NONE;
 }

 static irqreturn_t tiadc_worker_h(int irq, void *private)
 {
 	struct iio_dev *indio_dev = private;
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	int i, k, fifo1count, read;
 	u16 *data = adc_dev->data;

 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 	for (k = 0; k < fifo1count; k = k + i) {
 		for (i = 0; i < indio_dev->scan_bytes / 2; i++) {
 			read = tiadc_readl(adc_dev, REG_FIFO1);
 			data[i] = read & FIFOREAD_DATA_MASK;
 		}
 		iio_push_to_buffers(indio_dev, (u8 *)data);
 	}

 	tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
 	tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);

 	return IRQ_HANDLED;
 }

 static void tiadc_dma_rx_complete(void *param)
 {
 	struct iio_dev *indio_dev = param;
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	struct tiadc_dma *dma = &adc_dev->dma;
 	u8 *data;
 	int i;

 	data = dma->buf + dma->current_period * dma->period_size;
 	dma->current_period = 1 - dma->current_period; /* swap the buffer ID */

 	for (i = 0; i < dma->period_size; i += indio_dev->scan_bytes) {
 		iio_push_to_buffers(indio_dev, data);
 		data += indio_dev->scan_bytes;
 	}
 }

 static int tiadc_start_dma(struct iio_dev *indio_dev)
 {
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	struct tiadc_dma *dma = &adc_dev->dma;
 	struct dma_async_tx_descriptor *desc;

 	dma->current_period = 0; /* We start to fill period 0 */

 	/*
 	 * Make the fifo thresh as the multiple of total number of
 	 * channels enabled, so make sure that cyclic DMA period
 	 * length is also a multiple of total number of channels
 	 * enabled. This ensures that no invalid data is reported
 	 * to the stack via iio_push_to_buffers().
 	 */
 	dma->fifo_thresh = rounddown(FIFO1_THRESHOLD + 1,
 				     adc_dev->total_ch_enabled) - 1;

 	/* Make sure that period length is multiple of fifo thresh level */
 	dma->period_size = rounddown(DMA_BUFFER_SIZE / 2,
 				     (dma->fifo_thresh + 1) * sizeof(u16));

 	dma->conf.src_maxburst = dma->fifo_thresh + 1;
 	dmaengine_slave_config(dma->chan, &dma->conf);

 	desc = dmaengine_prep_dma_cyclic(dma->chan, dma->addr,
 					 dma->period_size * 2,
 					 dma->period_size, DMA_DEV_TO_MEM,
 					 DMA_PREP_INTERRUPT);
 	if (!desc)
 		return -EBUSY;

 	desc->callback = tiadc_dma_rx_complete;
 	desc->callback_param = indio_dev;

 	dma->cookie = dmaengine_submit(desc);

 	dma_async_issue_pending(dma->chan);

 	tiadc_writel(adc_dev, REG_FIFO1THR, dma->fifo_thresh);
 	tiadc_writel(adc_dev, REG_DMA1REQ, dma->fifo_thresh);
 	tiadc_writel(adc_dev, REG_DMAENABLE_SET, DMA_FIFO1);

 	return 0;
 }

 static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
 {
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	int i, fifo1count;
 	int ret;

 	ret = tiadc_wait_idle(adc_dev);
 	if (ret)
 		return ret;

 	tiadc_writel(adc_dev, REG_IRQCLR,
 		     IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN |
 		     IRQENB_FIFO1UNDRFLW);

 	/* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 	for (i = 0; i < fifo1count; i++)
 		tiadc_readl(adc_dev, REG_FIFO1);

 	return 0;
 }

 static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
 {
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	struct tiadc_dma *dma = &adc_dev->dma;
 	unsigned int irq_enable;
 	unsigned int enb = 0;
 	u8 bit;

 	tiadc_step_config(indio_dev);
 	for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) {
 		enb |= (get_adc_step_bit(adc_dev, bit) << 1);
 		adc_dev->total_ch_enabled++;
 	}
 	adc_dev->buffer_en_ch_steps = enb;

 	if (dma->chan)
 		tiadc_start_dma(indio_dev);

 	am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);

 	tiadc_writel(adc_dev, REG_IRQSTATUS,
 		     IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN |
 		     IRQENB_FIFO1UNDRFLW);

 	irq_enable = IRQENB_FIFO1OVRRUN;
 	if (!dma->chan)
 		irq_enable |= IRQENB_FIFO1THRES;
 	tiadc_writel(adc_dev,  REG_IRQENABLE, irq_enable);

 	return 0;
 }

 static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
 {
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	struct tiadc_dma *dma = &adc_dev->dma;
 	int fifo1count, i;

 	tiadc_writel(adc_dev, REG_IRQCLR,
 		     IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN |
 		     IRQENB_FIFO1UNDRFLW);
 	am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
 	adc_dev->buffer_en_ch_steps = 0;
 	adc_dev->total_ch_enabled = 0;
 	if (dma->chan) {
 		tiadc_writel(adc_dev, REG_DMAENABLE_CLEAR, 0x2);
 		dmaengine_terminate_async(dma->chan);
 	}

 	/* Flush FIFO of leftover data in the time it takes to disable adc */
 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 	for (i = 0; i < fifo1count; i++)
 		tiadc_readl(adc_dev, REG_FIFO1);

 	return 0;
 }

 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
 {
 	tiadc_step_config(indio_dev);

 	return 0;
 }

 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
 	.preenable = &tiadc_buffer_preenable,
 	.postenable = &tiadc_buffer_postenable,
 	.predisable = &tiadc_buffer_predisable,
 	.postdisable = &tiadc_buffer_postdisable,
 };

 static int tiadc_iio_buffered_hardware_setup(struct device *dev,
 					     struct iio_dev *indio_dev,
 					     irqreturn_t (*pollfunc_bh)(int irq, void *p),
 					     irqreturn_t (*pollfunc_th)(int irq, void *p),
 					     int irq, unsigned long flags,
 					     const struct iio_buffer_setup_ops *setup_ops)
 {
 	int ret;

 	ret = devm_iio_kfifo_buffer_setup(dev, indio_dev, setup_ops);
 	if (ret)
 		return ret;

 	return devm_request_threaded_irq(dev, irq, pollfunc_th, pollfunc_bh,
 					 flags, indio_dev->name, indio_dev);
 }

 static const char * const chan_name_ain[] = {
 	"AIN0",
 	"AIN1",
 	"AIN2",
 	"AIN3",
 	"AIN4",
 	"AIN5",
 	"AIN6",
 	"AIN7",
 };

 static int tiadc_channel_init(struct device *dev, struct iio_dev *indio_dev,
 			      int channels)
 {
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	struct iio_chan_spec *chan_array;
 	struct iio_chan_spec *chan;
 	int i;

 	indio_dev->num_channels = channels;
 	chan_array = devm_kcalloc(dev, channels, sizeof(*chan_array),
 				  GFP_KERNEL);
 	if (!chan_array)
 		return -ENOMEM;

 	chan = chan_array;
 	for (i = 0; i < channels; i++, chan++) {
 		chan->type = IIO_VOLTAGE;
 		chan->indexed = 1;
 		chan->channel = adc_dev->channel_line[i];
 		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
 		chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
 		chan->datasheet_name = chan_name_ain[chan->channel];
 		chan->scan_index = i;
 		chan->scan_type.sign = 'u';
 		chan->scan_type.realbits = 12;
 		chan->scan_type.storagebits = 16;
 	}

 	indio_dev->channels = chan_array;

 	return 0;
 }

 static int tiadc_read_raw(struct iio_dev *indio_dev,
 			  struct iio_chan_spec const *chan, int *val, int *val2,
 			  long mask)
 {
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	int i, map_val;
 	unsigned int fifo1count, read, stepid;
 	bool found = false;
 	u32 step_en;
 	unsigned long timeout;
 	int ret;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		break;
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->type) {
 		case IIO_VOLTAGE:
 			*val = 1800;
 			*val2 = chan->scan_type.realbits;
 			return IIO_VAL_FRACTIONAL_LOG2;
 		default:
 			return -EINVAL;
 		}
 		break;
 	default:
 		return -EINVAL;
 	}

 	if (iio_buffer_enabled(indio_dev))
 		return -EBUSY;

 	step_en = get_adc_chan_step_mask(adc_dev, chan);
 	if (!step_en)
 		return -EINVAL;

 	mutex_lock(&adc_dev->fifo1_lock);

 	ret = tiadc_wait_idle(adc_dev);
 	if (ret)
 		goto err_unlock;

 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 	while (fifo1count--)
 		tiadc_readl(adc_dev, REG_FIFO1);

 	am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);

 	/* Wait for Fifo threshold interrupt */
 	timeout = jiffies + msecs_to_jiffies(IDLE_TIMEOUT_MS * adc_dev->channels);
 	while (1) {
 		fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 		if (fifo1count)
 			break;

 		if (time_after(jiffies, timeout)) {
 			am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
 			ret = -EAGAIN;
 			goto err_unlock;
 		}
 	}

 	map_val = adc_dev->channel_step[chan->scan_index];

 	/*
 	 * We check the complete FIFO. We programmed just one entry but in case
 	 * something went wrong we left empty handed (-EAGAIN previously) and
 	 * then the value apeared somehow in the FIFO we would have two entries.
 	 * Therefore we read every item and keep only the latest version of the
 	 * requested channel.
 	 */
 	for (i = 0; i < fifo1count; i++) {
 		read = tiadc_readl(adc_dev, REG_FIFO1);
 		stepid = read & FIFOREAD_CHNLID_MASK;
 		stepid = stepid >> 0x10;

 		if (stepid == map_val) {
 			read = read & FIFOREAD_DATA_MASK;
 			found = true;
 			*val = (u16)read;
 		}
 	}

 	am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);

 	if (!found)
 		ret = -EBUSY;

 err_unlock:
 	mutex_unlock(&adc_dev->fifo1_lock);
 	return ret ? ret : IIO_VAL_INT;
 }

 static const struct iio_info tiadc_info = {
 	.read_raw = &tiadc_read_raw,
 };

 static int tiadc_request_dma(struct platform_device *pdev,
 			     struct tiadc_device *adc_dev)
 {
 	struct tiadc_dma	*dma = &adc_dev->dma;
 	dma_cap_mask_t		mask;

 	/* Default slave configuration parameters */
 	dma->conf.direction = DMA_DEV_TO_MEM;
 	dma->conf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 	dma->conf.src_addr = adc_dev->mfd_tscadc->tscadc_phys_base + REG_FIFO1;

 	dma_cap_zero(mask);
 	dma_cap_set(DMA_CYCLIC, mask);

 	/* Get a channel for RX */
 	dma->chan = dma_request_chan(adc_dev->mfd_tscadc->dev, "fifo1");
 	if (IS_ERR(dma->chan)) {
 		int ret = PTR_ERR(dma->chan);

 		dma->chan = NULL;
 		return ret;
 	}

 	/* RX buffer */
 	dma->buf = dma_alloc_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
 				      &dma->addr, GFP_KERNEL);
 	if (!dma->buf)
 		goto err;

 	return 0;

 err:
 	dma_release_channel(dma->chan);
 	return -ENOMEM;
 }

 static int tiadc_parse_dt(struct platform_device *pdev,
 			  struct tiadc_device *adc_dev)
 {
 	struct device_node *node = pdev->dev.of_node;
 	struct property *prop;
 	const __be32 *cur;
 	int channels = 0;
 	u32 val;
 	int i;

 	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
 		adc_dev->channel_line[channels] = val;

 		/* Set Default values for optional DT parameters */
 		adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
 		adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
 		adc_dev->step_avg[channels] = 16;

 		channels++;
 	}

 	adc_dev->channels = channels;

 	of_property_read_u32_array(node, "ti,chan-step-avg",
 				   adc_dev->step_avg, channels);
 	of_property_read_u32_array(node, "ti,chan-step-opendelay",
 				   adc_dev->open_delay, channels);
 	of_property_read_u32_array(node, "ti,chan-step-sampledelay",
 				   adc_dev->sample_delay, channels);

 	for (i = 0; i < adc_dev->channels; i++) {
 		int chan;

 		chan = adc_dev->channel_line[i];

 		if (adc_dev->step_avg[i] > STEPCONFIG_AVG_16) {
 			dev_warn(&pdev->dev,
 				 "chan %d: wrong step avg, truncated to %ld\n",
 				 chan, STEPCONFIG_AVG_16);
 			adc_dev->step_avg[i] = STEPCONFIG_AVG_16;
 		}

 		if (adc_dev->open_delay[i] > STEPCONFIG_MAX_OPENDLY) {
 			dev_warn(&pdev->dev,
 				 "chan %d: wrong open delay, truncated to 0x%lX\n",
 				 chan, STEPCONFIG_MAX_OPENDLY);
 			adc_dev->open_delay[i] = STEPCONFIG_MAX_OPENDLY;
 		}

 		if (adc_dev->sample_delay[i] > STEPCONFIG_MAX_SAMPLE) {
 			dev_warn(&pdev->dev,
 				 "chan %d: wrong sample delay, truncated to 0x%lX\n",
 				 chan, STEPCONFIG_MAX_SAMPLE);
 			adc_dev->sample_delay[i] = STEPCONFIG_MAX_SAMPLE;
 		}
 	}

 	return 0;
 }

 static int tiadc_probe(struct platform_device *pdev)
 {
 	struct iio_dev		*indio_dev;
 	struct tiadc_device	*adc_dev;
 	struct device_node	*node = pdev->dev.of_node;
 	int			err;

 	if (!node) {
 		dev_err(&pdev->dev, "Could not find valid DT data.\n");
 		return -EINVAL;
 	}

 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev));
 	if (!indio_dev) {
 		dev_err(&pdev->dev, "failed to allocate iio device\n");
 		return -ENOMEM;
 	}
 	adc_dev = iio_priv(indio_dev);

 	adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
 	tiadc_parse_dt(pdev, adc_dev);

 	indio_dev->name = dev_name(&pdev->dev);
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &tiadc_info;

 	tiadc_step_config(indio_dev);
 	tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
 	mutex_init(&adc_dev->fifo1_lock);

 	err = tiadc_channel_init(&pdev->dev, indio_dev, adc_dev->channels);
 	if (err < 0)
 		return err;

 	err = tiadc_iio_buffered_hardware_setup(&pdev->dev, indio_dev,
 						&tiadc_worker_h,
 						&tiadc_irq_h,
 						adc_dev->mfd_tscadc->irq,
 						IRQF_SHARED,
 						&tiadc_buffer_setup_ops);
 	if (err)
 		return err;

 	err = iio_device_register(indio_dev);
 	if (err)
 		return err;

 	platform_set_drvdata(pdev, indio_dev);

 	err = tiadc_request_dma(pdev, adc_dev);
 	if (err && err != -ENODEV) {
 		dev_err_probe(&pdev->dev, err, "DMA request failed\n");
 		goto err_dma;
 	}

 	return 0;

 err_dma:
 	iio_device_unregister(indio_dev);

 	return err;
 }

 static void tiadc_remove(struct platform_device *pdev)
 {
 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	struct tiadc_dma *dma = &adc_dev->dma;
 	u32 step_en;

 	if (dma->chan) {
 		dma_free_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
 				  dma->buf, dma->addr);
 		dma_release_channel(dma->chan);
 	}
 	iio_device_unregister(indio_dev);

 	step_en = get_adc_step_mask(adc_dev);
 	am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
 }

 static int tiadc_suspend(struct device *dev)
 {
 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	unsigned int idle;

 	idle = tiadc_readl(adc_dev, REG_CTRL);
 	idle &= ~(CNTRLREG_SSENB);
 	tiadc_writel(adc_dev, REG_CTRL, idle | CNTRLREG_POWERDOWN);

 	return 0;
 }

 static int tiadc_resume(struct device *dev)
 {
 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	unsigned int restore;

 	/* Make sure ADC is powered up */
 	restore = tiadc_readl(adc_dev, REG_CTRL);
 	restore &= ~CNTRLREG_POWERDOWN;
 	tiadc_writel(adc_dev, REG_CTRL, restore);

 	tiadc_step_config(indio_dev);
 	am335x_tsc_se_set_cache(adc_dev->mfd_tscadc,
 				adc_dev->buffer_en_ch_steps);
 	return 0;
 }

 static DEFINE_SIMPLE_DEV_PM_OPS(tiadc_pm_ops, tiadc_suspend, tiadc_resume);

 static const struct of_device_id ti_adc_dt_ids[] = {
 	{ .compatible = "ti,am3359-adc", },
 	{ .compatible = "ti,am4372-adc", },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);

 static struct platform_driver tiadc_driver = {
 	.driver = {
 		.name   = "TI-am335x-adc",
 		.pm	= pm_sleep_ptr(&tiadc_pm_ops),
 		.of_match_table = ti_adc_dt_ids,
 	},
 	.probe	= tiadc_probe,
 	.remove_new = tiadc_remove,
 };
 module_platform_driver(tiadc_driver);

 MODULE_DESCRIPTION("TI ADC controller driver");
 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* TI ADC MFD driver
	*
	* Copyright (C) 2012 Texas Instruments Incorporated - https://www.ti.com/
	*/

	#include <linux/kernel.h>
	#include <linux/err.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/interrupt.h>
	#include <linux/platform_device.h>
	#include <linux/io.h>
	#include <linux/iio/iio.h>
	#include <linux/of.h>
	#include <linux/iio/machine.h>
	#include <linux/iio/driver.h>
	#include <linux/iopoll.h>

	#include <linux/mfd/ti_am335x_tscadc.h>
	#include <linux/iio/buffer.h>
	#include <linux/iio/kfifo_buf.h>

	#include <linux/dmaengine.h>
	#include <linux/dma-mapping.h>

	#define DMA_BUFFER_SIZE SZ_2K

	struct tiadc_dma {
	struct dma_slave_config conf;
	struct dma_chan *chan;
	dma_addr_t addr;
	dma_cookie_t cookie;
	u8 *buf;
	int current_period;
	int period_size;
	u8 fifo_thresh;
	};

	struct tiadc_device {
	struct ti_tscadc_dev *mfd_tscadc;
	struct tiadc_dma dma;
	struct mutex fifo1_lock; /* to protect fifo access */
	int channels;
	int total_ch_enabled;
	u8 channel_line[8];
	u8 channel_step[8];
	int buffer_en_ch_steps;
	u16 data[8];
	u32 open_delay[8], sample_delay[8], step_avg[8];
	};

	static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
	{
	return readl(adc->mfd_tscadc->tscadc_base + reg);
	}

	static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
	unsigned int val)
	{
	writel(val, adc->mfd_tscadc->tscadc_base + reg);
	}

	static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
	{
	u32 step_en;

	step_en = ((1 << adc_dev->channels) - 1);
	step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
	return step_en;
	}

	static u32 get_adc_chan_step_mask(struct tiadc_device *adc_dev,
	struct iio_chan_spec const *chan)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
	if (chan->channel == adc_dev->channel_line[i]) {
	u32 step;

	step = adc_dev->channel_step[i];
	/* +1 for the charger */
	return 1 << (step + 1);
	}
	}
	WARN_ON(1);
	return 0;
	}

	static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
	{
	return 1 << adc_dev->channel_step[chan];
	}

	static int tiadc_wait_idle(struct tiadc_device *adc_dev)
	{
	u32 val;

	return readl_poll_timeout(adc_dev->mfd_tscadc->tscadc_base + REG_ADCFSM,
	val, !(val & SEQ_STATUS), 10,
	IDLE_TIMEOUT_MS * 1000 * adc_dev->channels);
	}

	static void tiadc_step_config(struct iio_dev *indio_dev)
	{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	unsigned int stepconfig;
	int i, steps = 0;

	/*
	* There are 16 configurable steps and 8 analog input
	* lines available which are shared between Touchscreen and ADC.
	*
	* Steps forwards i.e. from 0 towards 16 are used by ADC
	* depending on number of input lines needed.
	* Channel would represent which analog input
	* needs to be given to ADC to digitalize data.
	*/
	for (i = 0; i < adc_dev->channels; i++) {
	int chan;

	chan = adc_dev->channel_line[i];

	if (adc_dev->step_avg[i])
	stepconfig = STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) \|
	STEPCONFIG_FIFO1;
	else
	stepconfig = STEPCONFIG_FIFO1;

	if (iio_buffer_enabled(indio_dev))
	stepconfig \|= STEPCONFIG_MODE_SWCNT;

	tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
	stepconfig \| STEPCONFIG_INP(chan) \|
	STEPCONFIG_INM_ADCREFM \| STEPCONFIG_RFP_VREFP \|
	STEPCONFIG_RFM_VREFN);

	tiadc_writel(adc_dev, REG_STEPDELAY(steps),
	STEPDELAY_OPEN(adc_dev->open_delay[i]) \|
	STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));

	adc_dev->channel_step[i] = steps;
	steps++;
	}
	}

	static irqreturn_t tiadc_irq_h(int irq, void *private)
	{
	struct iio_dev *indio_dev = private;
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	unsigned int status, config, adc_fsm;
	unsigned short count = 0;

	status = tiadc_readl(adc_dev, REG_IRQSTATUS);

	/*
	* ADC and touchscreen share the IRQ line.
	* FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
	*/
	if (status & IRQENB_FIFO1OVRRUN) {
	/* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
	config = tiadc_readl(adc_dev, REG_CTRL);
	config &= ~(CNTRLREG_SSENB);
	tiadc_writel(adc_dev, REG_CTRL, config);
	tiadc_writel(adc_dev, REG_IRQSTATUS,
	IRQENB_FIFO1OVRRUN \| IRQENB_FIFO1UNDRFLW \|
	IRQENB_FIFO1THRES);

	/*
	* Wait for the idle state.
	* ADC needs to finish the current conversion
	* before disabling the module
	*/
	do {
	adc_fsm = tiadc_readl(adc_dev, REG_ADCFSM);
	} while (adc_fsm != 0x10 && count++ < 100);

	tiadc_writel(adc_dev, REG_CTRL, (config \| CNTRLREG_SSENB));
	return IRQ_HANDLED;
	} else if (status & IRQENB_FIFO1THRES) {
	/* Disable irq and wake worker thread */
	tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
	return IRQ_WAKE_THREAD;
	}

	return IRQ_NONE;
	}

	static irqreturn_t tiadc_worker_h(int irq, void *private)
	{
	struct iio_dev *indio_dev = private;
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	int i, k, fifo1count, read;
	u16 *data = adc_dev->data;

	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	for (k = 0; k < fifo1count; k = k + i) {
	for (i = 0; i < indio_dev->scan_bytes / 2; i++) {
	read = tiadc_readl(adc_dev, REG_FIFO1);
	data[i] = read & FIFOREAD_DATA_MASK;
	}
	iio_push_to_buffers(indio_dev, (u8 *)data);
	}

	tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
	tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);

	return IRQ_HANDLED;
	}

	static void tiadc_dma_rx_complete(void *param)
	{
	struct iio_dev *indio_dev = param;
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	struct tiadc_dma *dma = &adc_dev->dma;
	u8 *data;
	int i;

	data = dma->buf + dma->current_period * dma->period_size;
	dma->current_period = 1 - dma->current_period; /* swap the buffer ID */

	for (i = 0; i < dma->period_size; i += indio_dev->scan_bytes) {
	iio_push_to_buffers(indio_dev, data);
	data += indio_dev->scan_bytes;
	}
	}

	static int tiadc_start_dma(struct iio_dev *indio_dev)
	{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	struct tiadc_dma *dma = &adc_dev->dma;
	struct dma_async_tx_descriptor *desc;

	dma->current_period = 0; /* We start to fill period 0 */

	/*
	* Make the fifo thresh as the multiple of total number of
	* channels enabled, so make sure that cyclic DMA period
	* length is also a multiple of total number of channels
	* enabled. This ensures that no invalid data is reported
	* to the stack via iio_push_to_buffers().
	*/
	dma->fifo_thresh = rounddown(FIFO1_THRESHOLD + 1,
	adc_dev->total_ch_enabled) - 1;

	/* Make sure that period length is multiple of fifo thresh level */
	dma->period_size = rounddown(DMA_BUFFER_SIZE / 2,
	(dma->fifo_thresh + 1) * sizeof(u16));

	dma->conf.src_maxburst = dma->fifo_thresh + 1;
	dmaengine_slave_config(dma->chan, &dma->conf);

	desc = dmaengine_prep_dma_cyclic(dma->chan, dma->addr,
	dma->period_size * 2,
	dma->period_size, DMA_DEV_TO_MEM,
	DMA_PREP_INTERRUPT);
	if (!desc)
	return -EBUSY;

	desc->callback = tiadc_dma_rx_complete;
	desc->callback_param = indio_dev;

	dma->cookie = dmaengine_submit(desc);

	dma_async_issue_pending(dma->chan);

	tiadc_writel(adc_dev, REG_FIFO1THR, dma->fifo_thresh);
	tiadc_writel(adc_dev, REG_DMA1REQ, dma->fifo_thresh);
	tiadc_writel(adc_dev, REG_DMAENABLE_SET, DMA_FIFO1);

	return 0;
	}

	static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
	{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	int i, fifo1count;
	int ret;

	ret = tiadc_wait_idle(adc_dev);
	if (ret)
	return ret;

	tiadc_writel(adc_dev, REG_IRQCLR,
	IRQENB_FIFO1THRES \| IRQENB_FIFO1OVRRUN \|
	IRQENB_FIFO1UNDRFLW);

	/* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	for (i = 0; i < fifo1count; i++)
	tiadc_readl(adc_dev, REG_FIFO1);

	return 0;
	}

	static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
	{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	struct tiadc_dma *dma = &adc_dev->dma;
	unsigned int irq_enable;
	unsigned int enb = 0;
	u8 bit;

	tiadc_step_config(indio_dev);
	for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) {
	enb \|= (get_adc_step_bit(adc_dev, bit) << 1);
	adc_dev->total_ch_enabled++;
	}
	adc_dev->buffer_en_ch_steps = enb;

	if (dma->chan)
	tiadc_start_dma(indio_dev);

	am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);

	tiadc_writel(adc_dev, REG_IRQSTATUS,
	IRQENB_FIFO1THRES \| IRQENB_FIFO1OVRRUN \|
	IRQENB_FIFO1UNDRFLW);

	irq_enable = IRQENB_FIFO1OVRRUN;
	if (!dma->chan)
	irq_enable \|= IRQENB_FIFO1THRES;
	tiadc_writel(adc_dev, REG_IRQENABLE, irq_enable);

	return 0;
	}

	static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
	{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	struct tiadc_dma *dma = &adc_dev->dma;
	int fifo1count, i;

	tiadc_writel(adc_dev, REG_IRQCLR,
	IRQENB_FIFO1THRES \| IRQENB_FIFO1OVRRUN \|
	IRQENB_FIFO1UNDRFLW);
	am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
	adc_dev->buffer_en_ch_steps = 0;
	adc_dev->total_ch_enabled = 0;
	if (dma->chan) {
	tiadc_writel(adc_dev, REG_DMAENABLE_CLEAR, 0x2);
	dmaengine_terminate_async(dma->chan);
	}

	/* Flush FIFO of leftover data in the time it takes to disable adc */
	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	for (i = 0; i < fifo1count; i++)
	tiadc_readl(adc_dev, REG_FIFO1);

	return 0;
	}

	static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
	{
	tiadc_step_config(indio_dev);

	return 0;
	}

	static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
	.preenable = &tiadc_buffer_preenable,
	.postenable = &tiadc_buffer_postenable,
	.predisable = &tiadc_buffer_predisable,
	.postdisable = &tiadc_buffer_postdisable,
	};

	static int tiadc_iio_buffered_hardware_setup(struct device *dev,
	struct iio_dev *indio_dev,
	irqreturn_t (pollfunc_bh)(int irq, void p),
	irqreturn_t (pollfunc_th)(int irq, void p),
	int irq, unsigned long flags,
	const struct iio_buffer_setup_ops *setup_ops)
	{
	int ret;

	ret = devm_iio_kfifo_buffer_setup(dev, indio_dev, setup_ops);
	if (ret)
	return ret;

	return devm_request_threaded_irq(dev, irq, pollfunc_th, pollfunc_bh,
	flags, indio_dev->name, indio_dev);
	}

	static const char * const chan_name_ain[] = {
	"AIN0",
	"AIN1",
	"AIN2",
	"AIN3",
	"AIN4",
	"AIN5",
	"AIN6",
	"AIN7",
	};

	static int tiadc_channel_init(struct device dev, struct iio_dev indio_dev,
	int channels)
	{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	struct iio_chan_spec *chan_array;
	struct iio_chan_spec *chan;
	int i;

	indio_dev->num_channels = channels;
	chan_array = devm_kcalloc(dev, channels, sizeof(*chan_array),
	GFP_KERNEL);
	if (!chan_array)
	return -ENOMEM;

	chan = chan_array;
	for (i = 0; i < channels; i++, chan++) {
	chan->type = IIO_VOLTAGE;
	chan->indexed = 1;
	chan->channel = adc_dev->channel_line[i];
	chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
	chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
	chan->datasheet_name = chan_name_ain[chan->channel];
	chan->scan_index = i;
	chan->scan_type.sign = 'u';
	chan->scan_type.realbits = 12;
	chan->scan_type.storagebits = 16;
	}

	indio_dev->channels = chan_array;

	return 0;
	}

	static int tiadc_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const chan, int val, int *val2,
	long mask)
	{
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	int i, map_val;
	unsigned int fifo1count, read, stepid;
	bool found = false;
	u32 step_en;
	unsigned long timeout;
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	break;
	case IIO_CHAN_INFO_SCALE:
	switch (chan->type) {
	case IIO_VOLTAGE:
	*val = 1800;
	*val2 = chan->scan_type.realbits;
	return IIO_VAL_FRACTIONAL_LOG2;
	default:
	return -EINVAL;
	}
	break;
	default:
	return -EINVAL;
	}

	if (iio_buffer_enabled(indio_dev))
	return -EBUSY;

	step_en = get_adc_chan_step_mask(adc_dev, chan);
	if (!step_en)
	return -EINVAL;

	mutex_lock(&adc_dev->fifo1_lock);

	ret = tiadc_wait_idle(adc_dev);
	if (ret)
	goto err_unlock;

	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	while (fifo1count--)
	tiadc_readl(adc_dev, REG_FIFO1);

	am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);

	/* Wait for Fifo threshold interrupt */
	timeout = jiffies + msecs_to_jiffies(IDLE_TIMEOUT_MS * adc_dev->channels);
	while (1) {
	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
	if (fifo1count)
	break;

	if (time_after(jiffies, timeout)) {
	am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
	ret = -EAGAIN;
	goto err_unlock;
	}
	}

	map_val = adc_dev->channel_step[chan->scan_index];

	/*
	* We check the complete FIFO. We programmed just one entry but in case
	* something went wrong we left empty handed (-EAGAIN previously) and
	* then the value apeared somehow in the FIFO we would have two entries.
	* Therefore we read every item and keep only the latest version of the
	* requested channel.
	*/
	for (i = 0; i < fifo1count; i++) {
	read = tiadc_readl(adc_dev, REG_FIFO1);
	stepid = read & FIFOREAD_CHNLID_MASK;
	stepid = stepid >> 0x10;

	if (stepid == map_val) {
	read = read & FIFOREAD_DATA_MASK;
	found = true;
	*val = (u16)read;
	}
	}

	am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);

	if (!found)
	ret = -EBUSY;

	err_unlock:
	mutex_unlock(&adc_dev->fifo1_lock);
	return ret ? ret : IIO_VAL_INT;
	}

	static const struct iio_info tiadc_info = {
	.read_raw = &tiadc_read_raw,
	};

	static int tiadc_request_dma(struct platform_device *pdev,
	struct tiadc_device *adc_dev)
	{
	struct tiadc_dma *dma = &adc_dev->dma;
	dma_cap_mask_t mask;

	/* Default slave configuration parameters */
	dma->conf.direction = DMA_DEV_TO_MEM;
	dma->conf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
	dma->conf.src_addr = adc_dev->mfd_tscadc->tscadc_phys_base + REG_FIFO1;

	dma_cap_zero(mask);
	dma_cap_set(DMA_CYCLIC, mask);

	/* Get a channel for RX */
	dma->chan = dma_request_chan(adc_dev->mfd_tscadc->dev, "fifo1");
	if (IS_ERR(dma->chan)) {
	int ret = PTR_ERR(dma->chan);

	dma->chan = NULL;
	return ret;
	}

	/* RX buffer */
	dma->buf = dma_alloc_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
	&dma->addr, GFP_KERNEL);
	if (!dma->buf)
	goto err;

	return 0;

	err:
	dma_release_channel(dma->chan);
	return -ENOMEM;
	}

	static int tiadc_parse_dt(struct platform_device *pdev,
	struct tiadc_device *adc_dev)
	{
	struct device_node *node = pdev->dev.of_node;
	struct property *prop;
	const __be32 *cur;
	int channels = 0;
	u32 val;
	int i;

	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
	adc_dev->channel_line[channels] = val;

	/* Set Default values for optional DT parameters */
	adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
	adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
	adc_dev->step_avg[channels] = 16;

	channels++;
	}

	adc_dev->channels = channels;

	of_property_read_u32_array(node, "ti,chan-step-avg",
	adc_dev->step_avg, channels);
	of_property_read_u32_array(node, "ti,chan-step-opendelay",
	adc_dev->open_delay, channels);
	of_property_read_u32_array(node, "ti,chan-step-sampledelay",
	adc_dev->sample_delay, channels);

	for (i = 0; i < adc_dev->channels; i++) {
	int chan;

	chan = adc_dev->channel_line[i];

	if (adc_dev->step_avg[i] > STEPCONFIG_AVG_16) {
	dev_warn(&pdev->dev,
	"chan %d: wrong step avg, truncated to %ld\n",
	chan, STEPCONFIG_AVG_16);
	adc_dev->step_avg[i] = STEPCONFIG_AVG_16;
	}

	if (adc_dev->open_delay[i] > STEPCONFIG_MAX_OPENDLY) {
	dev_warn(&pdev->dev,
	"chan %d: wrong open delay, truncated to 0x%lX\n",
	chan, STEPCONFIG_MAX_OPENDLY);
	adc_dev->open_delay[i] = STEPCONFIG_MAX_OPENDLY;
	}

	if (adc_dev->sample_delay[i] > STEPCONFIG_MAX_SAMPLE) {
	dev_warn(&pdev->dev,
	"chan %d: wrong sample delay, truncated to 0x%lX\n",
	chan, STEPCONFIG_MAX_SAMPLE);
	adc_dev->sample_delay[i] = STEPCONFIG_MAX_SAMPLE;
	}
	}

	return 0;
	}

	static int tiadc_probe(struct platform_device *pdev)
	{
	struct iio_dev *indio_dev;
	struct tiadc_device *adc_dev;
	struct device_node *node = pdev->dev.of_node;
	int err;

	if (!node) {
	dev_err(&pdev->dev, "Could not find valid DT data.\n");
	return -EINVAL;
	}

	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev));
	if (!indio_dev) {
	dev_err(&pdev->dev, "failed to allocate iio device\n");
	return -ENOMEM;
	}
	adc_dev = iio_priv(indio_dev);

	adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
	tiadc_parse_dt(pdev, adc_dev);

	indio_dev->name = dev_name(&pdev->dev);
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &tiadc_info;

	tiadc_step_config(indio_dev);
	tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
	mutex_init(&adc_dev->fifo1_lock);

	err = tiadc_channel_init(&pdev->dev, indio_dev, adc_dev->channels);
	if (err < 0)
	return err;

	err = tiadc_iio_buffered_hardware_setup(&pdev->dev, indio_dev,
	&tiadc_worker_h,
	&tiadc_irq_h,
	adc_dev->mfd_tscadc->irq,
	IRQF_SHARED,
	&tiadc_buffer_setup_ops);
	if (err)
	return err;

	err = iio_device_register(indio_dev);
	if (err)
	return err;

	platform_set_drvdata(pdev, indio_dev);

	err = tiadc_request_dma(pdev, adc_dev);
	if (err && err != -ENODEV) {
	dev_err_probe(&pdev->dev, err, "DMA request failed\n");
	goto err_dma;
	}

	return 0;

	err_dma:
	iio_device_unregister(indio_dev);

	return err;
	}

	static void tiadc_remove(struct platform_device *pdev)
	{
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	struct tiadc_dma *dma = &adc_dev->dma;
	u32 step_en;

	if (dma->chan) {
	dma_free_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
	dma->buf, dma->addr);
	dma_release_channel(dma->chan);
	}
	iio_device_unregister(indio_dev);

	step_en = get_adc_step_mask(adc_dev);
	am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
	}

	static int tiadc_suspend(struct device *dev)
	{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	unsigned int idle;

	idle = tiadc_readl(adc_dev, REG_CTRL);
	idle &= ~(CNTRLREG_SSENB);
	tiadc_writel(adc_dev, REG_CTRL, idle \| CNTRLREG_POWERDOWN);

	return 0;
	}

	static int tiadc_resume(struct device *dev)
	{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	unsigned int restore;

	/* Make sure ADC is powered up */
	restore = tiadc_readl(adc_dev, REG_CTRL);
	restore &= ~CNTRLREG_POWERDOWN;
	tiadc_writel(adc_dev, REG_CTRL, restore);

	tiadc_step_config(indio_dev);
	am335x_tsc_se_set_cache(adc_dev->mfd_tscadc,
	adc_dev->buffer_en_ch_steps);
	return 0;
	}

	static DEFINE_SIMPLE_DEV_PM_OPS(tiadc_pm_ops, tiadc_suspend, tiadc_resume);

	static const struct of_device_id ti_adc_dt_ids[] = {
	{ .compatible = "ti,am3359-adc", },
	{ .compatible = "ti,am4372-adc", },
	{ }
	};
	MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);

	static struct platform_driver tiadc_driver = {
	.driver = {
	.name = "TI-am335x-adc",
	.pm = pm_sleep_ptr(&tiadc_pm_ops),
	.of_match_table = ti_adc_dt_ids,
	},
	.probe = tiadc_probe,
	.remove_new = tiadc_remove,
	};
	module_platform_driver(tiadc_driver);

	MODULE_DESCRIPTION("TI ADC controller driver");
	MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
	MODULE_LICENSE("GPL");