/*
 * TI ADC MFD driver
 *
 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.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.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#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/of_device.h>
#include <linux/iio/machine.h>
#include <linux/iio/driver.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 void tiadc_step_config(struct iio_dev *indio_dev)
{
        struct tiadc_device *adc_dev = iio_priv(indio_dev);
        struct device *dev = adc_dev->mfd_tscadc->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_AVG_16) {
                        dev_warn(dev, "chan %d step_avg truncating to %d\n",
                                 chan, STEPCONFIG_AVG_16);
                        adc_dev->step_avg[i] = STEPCONFIG_AVG_16;
                }

                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));

                if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MASK) {
                        dev_warn(dev, "chan %d open delay truncating to 0x3FFFF\n",
                                 chan);
                        adc_dev->open_delay[i] = STEPDELAY_OPEN_MASK;
                }

                if (adc_dev->sample_delay[i] > 0xFF) {
                        dev_warn(dev, "chan %d sample delay truncating to 0xFF\n",
                                 chan);
                        adc_dev->sample_delay[i] = 0xFF;
                }

                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_TSCSSENB);
                tiadc_writel(adc_dev, REG_CTRL, config);
                tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN
                                | IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES);

                /* wait for 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_TSCSSENB));
                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, read;

        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++)
                read = 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, read;

        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++)
                read = 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 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)
{
        struct iio_buffer *buffer;
        int ret;

        buffer = iio_kfifo_allocate();
        if (!buffer)
                return -ENOMEM;

        iio_device_attach_buffer(indio_dev, buffer);

        ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh,
                                flags, indio_dev->name, indio_dev);
        if (ret)
                goto error_kfifo_free;

        indio_dev->setup_ops = setup_ops;
        indio_dev->modes |= INDIO_BUFFER_SOFTWARE;

        return 0;

error_kfifo_free:
        iio_kfifo_free(indio_dev->buffer);
        return ret;
}

static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev)
{
        struct tiadc_device *adc_dev = iio_priv(indio_dev);

        free_irq(adc_dev->mfd_tscadc->irq, indio_dev);
        iio_kfifo_free(indio_dev->buffer);
}


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

static int tiadc_channel_init(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 = kcalloc(channels, sizeof(*chan_array), GFP_KERNEL);
        if (chan_array == NULL)
                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->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 void tiadc_channels_remove(struct iio_dev *indio_dev)
{
        kfree(indio_dev->channels);
}

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 ret = IIO_VAL_INT;
        int i, map_val;
        unsigned int fifo1count, read, stepid;
        bool found = false;
        u32 step_en;
        unsigned long timeout;

        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);
        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);

        timeout = jiffies + msecs_to_jiffies
                                (IDLE_TIMEOUT * adc_dev->channels);
        /* Wait for Fifo threshold interrupt */
        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;
}

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;

        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++;
        }

        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);

        adc_dev->channels = channels;
        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 == NULL) {
                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->dev.parent = &pdev->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(indio_dev, adc_dev->channels);
        if (err < 0)
                return err;

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

        if (err)
                goto err_free_channels;

        err = iio_device_register(indio_dev);
        if (err)
                goto err_buffer_unregister;

        platform_set_drvdata(pdev, indio_dev);

        err = tiadc_request_dma(pdev, adc_dev);
        if (err && err == -EPROBE_DEFER)
                goto err_dma;

        return 0;

err_dma:
        iio_device_unregister(indio_dev);
err_buffer_unregister:
        tiadc_iio_buffered_hardware_remove(indio_dev);
err_free_channels:
        tiadc_channels_remove(indio_dev);
        return err;
}

static int 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);
        tiadc_iio_buffered_hardware_remove(indio_dev);
        tiadc_channels_remove(indio_dev);

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

        return 0;
}

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

        tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
        if (!device_may_wakeup(tscadc_dev->dev)) {
                idle = tiadc_readl(adc_dev, REG_CTRL);
                idle &= ~(CNTRLREG_TSCSSENB);
                tiadc_writel(adc_dev, REG_CTRL, (idle |
                                CNTRLREG_POWERDOWN));
        }

        return 0;
}

static int __maybe_unused 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 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", },
        { }
};
MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);

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

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