Initial import

1 files changed, 1438 insertions, 0 deletions

diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
new file mode 100644
index 000000000..7b40925dd
--- /dev/null
+++ b/drivers/iio/adc/at91_adc.c
@@ -0,0 +1,1438 @@
+/*
+ * Driver for the ADC present in the Atmel AT91 evaluation boards.
+ *
+ * Copyright 2011 Free Electrons
+ *
+ * Licensed under the GPLv2 or later.
+ */
+
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+
+#include <linux/platform_data/at91_adc.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+/* Registers */
+#define AT91_ADC_CR		0x00		/* Control Register */
+#define		AT91_ADC_SWRST		(1 << 0)	/* Software Reset */
+#define		AT91_ADC_START		(1 << 1)	/* Start Conversion */
+
+#define AT91_ADC_MR		0x04		/* Mode Register */
+#define		AT91_ADC_TSAMOD		(3 << 0)	/* ADC mode */
+#define		AT91_ADC_TSAMOD_ADC_ONLY_MODE		(0 << 0)	/* ADC Mode */
+#define		AT91_ADC_TSAMOD_TS_ONLY_MODE		(1 << 0)	/* Touch Screen Only Mode */
+#define		AT91_ADC_TRGEN		(1 << 0)	/* Trigger Enable */
+#define		AT91_ADC_TRGSEL		(7 << 1)	/* Trigger Selection */
+#define			AT91_ADC_TRGSEL_TC0		(0 << 1)
+#define			AT91_ADC_TRGSEL_TC1		(1 << 1)
+#define			AT91_ADC_TRGSEL_TC2		(2 << 1)
+#define			AT91_ADC_TRGSEL_EXTERNAL	(6 << 1)
+#define		AT91_ADC_LOWRES		(1 << 4)	/* Low Resolution */
+#define		AT91_ADC_SLEEP		(1 << 5)	/* Sleep Mode */
+#define		AT91_ADC_PENDET		(1 << 6)	/* Pen contact detection enable */
+#define		AT91_ADC_PRESCAL_9260	(0x3f << 8)	/* Prescalar Rate Selection */
+#define		AT91_ADC_PRESCAL_9G45	(0xff << 8)
+#define			AT91_ADC_PRESCAL_(x)	((x) << 8)
+#define		AT91_ADC_STARTUP_9260	(0x1f << 16)	/* Startup Up Time */
+#define		AT91_ADC_STARTUP_9G45	(0x7f << 16)
+#define		AT91_ADC_STARTUP_9X5	(0xf << 16)
+#define			AT91_ADC_STARTUP_(x)	((x) << 16)
+#define		AT91_ADC_SHTIM		(0xf  << 24)	/* Sample & Hold Time */
+#define			AT91_ADC_SHTIM_(x)	((x) << 24)
+#define		AT91_ADC_PENDBC		(0x0f << 28)	/* Pen Debounce time */
+#define			AT91_ADC_PENDBC_(x)	((x) << 28)
+
+#define AT91_ADC_TSR		0x0C
+#define		AT91_ADC_TSR_SHTIM	(0xf  << 24)	/* Sample & Hold Time */
+#define			AT91_ADC_TSR_SHTIM_(x)	((x) << 24)
+
+#define AT91_ADC_CHER		0x10		/* Channel Enable Register */
+#define AT91_ADC_CHDR		0x14		/* Channel Disable Register */
+#define AT91_ADC_CHSR		0x18		/* Channel Status Register */
+#define		AT91_ADC_CH(n)		(1 << (n))	/* Channel Number */
+
+#define AT91_ADC_SR		0x1C		/* Status Register */
+#define		AT91_ADC_EOC(n)		(1 << (n))	/* End of Conversion on Channel N */
+#define		AT91_ADC_OVRE(n)	(1 << ((n) + 8))/* Overrun Error on Channel N */
+#define		AT91_ADC_DRDY		(1 << 16)	/* Data Ready */
+#define		AT91_ADC_GOVRE		(1 << 17)	/* General Overrun Error */
+#define		AT91_ADC_ENDRX		(1 << 18)	/* End of RX Buffer */
+#define		AT91_ADC_RXFUFF		(1 << 19)	/* RX Buffer Full */
+
+#define AT91_ADC_SR_9X5		0x30		/* Status Register for 9x5 */
+#define		AT91_ADC_SR_DRDY_9X5	(1 << 24)	/* Data Ready */
+
+#define AT91_ADC_LCDR		0x20		/* Last Converted Data Register */
+#define		AT91_ADC_LDATA		(0x3ff)
+
+#define AT91_ADC_IER		0x24		/* Interrupt Enable Register */
+#define AT91_ADC_IDR		0x28		/* Interrupt Disable Register */
+#define AT91_ADC_IMR		0x2C		/* Interrupt Mask Register */
+#define		AT91RL_ADC_IER_PEN	(1 << 20)
+#define		AT91RL_ADC_IER_NOPEN	(1 << 21)
+#define		AT91_ADC_IER_PEN	(1 << 29)
+#define		AT91_ADC_IER_NOPEN	(1 << 30)
+#define		AT91_ADC_IER_XRDY	(1 << 20)
+#define		AT91_ADC_IER_YRDY	(1 << 21)
+#define		AT91_ADC_IER_PRDY	(1 << 22)
+#define		AT91_ADC_ISR_PENS	(1 << 31)
+
+#define AT91_ADC_CHR(n)		(0x30 + ((n) * 4))	/* Channel Data Register N */
+#define		AT91_ADC_DATA		(0x3ff)
+
+#define AT91_ADC_CDR0_9X5	(0x50)			/* Channel Data Register 0 for 9X5 */
+
+#define AT91_ADC_ACR		0x94	/* Analog Control Register */
+#define		AT91_ADC_ACR_PENDETSENS	(0x3 << 0)	/* pull-up resistor */
+
+#define AT91_ADC_TSMR		0xB0
+#define		AT91_ADC_TSMR_TSMODE	(3 << 0)	/* Touch Screen Mode */
+#define			AT91_ADC_TSMR_TSMODE_NONE		(0 << 0)
+#define			AT91_ADC_TSMR_TSMODE_4WIRE_NO_PRESS	(1 << 0)
+#define			AT91_ADC_TSMR_TSMODE_4WIRE_PRESS	(2 << 0)
+#define			AT91_ADC_TSMR_TSMODE_5WIRE		(3 << 0)
+#define		AT91_ADC_TSMR_TSAV	(3 << 4)	/* Averages samples */
+#define			AT91_ADC_TSMR_TSAV_(x)		((x) << 4)
+#define		AT91_ADC_TSMR_SCTIM	(0x0f << 16)	/* Switch closure time */
+#define		AT91_ADC_TSMR_PENDBC	(0x0f << 28)	/* Pen Debounce time */
+#define			AT91_ADC_TSMR_PENDBC_(x)	((x) << 28)
+#define		AT91_ADC_TSMR_NOTSDMA	(1 << 22)	/* No Touchscreen DMA */
+#define		AT91_ADC_TSMR_PENDET_DIS	(0 << 24)	/* Pen contact detection disable */
+#define		AT91_ADC_TSMR_PENDET_ENA	(1 << 24)	/* Pen contact detection enable */
+
+#define AT91_ADC_TSXPOSR	0xB4
+#define AT91_ADC_TSYPOSR	0xB8
+#define AT91_ADC_TSPRESSR	0xBC
+
+#define AT91_ADC_TRGR_9260	AT91_ADC_MR
+#define AT91_ADC_TRGR_9G45	0x08
+#define AT91_ADC_TRGR_9X5	0xC0
+
+/* Trigger Register bit field */
+#define		AT91_ADC_TRGR_TRGPER	(0xffff << 16)
+#define			AT91_ADC_TRGR_TRGPER_(x)	((x) << 16)
+#define		AT91_ADC_TRGR_TRGMOD	(0x7 << 0)
+#define			AT91_ADC_TRGR_NONE		(0 << 0)
+#define			AT91_ADC_TRGR_MOD_PERIOD_TRIG	(5 << 0)
+
+#define AT91_ADC_CHAN(st, ch) \
+	(st->registers->channel_base + (ch * 4))
+#define at91_adc_readl(st, reg) \
+	(readl_relaxed(st->reg_base + reg))
+#define at91_adc_writel(st, reg, val) \
+	(writel_relaxed(val, st->reg_base + reg))
+
+#define DRIVER_NAME		"at91_adc"
+#define MAX_POS_BITS		12
+
+#define TOUCH_SAMPLE_PERIOD_US		2000	/* 2ms */
+#define TOUCH_PEN_DETECT_DEBOUNCE_US	200
+
+#define MAX_RLPOS_BITS         10
+#define TOUCH_SAMPLE_PERIOD_US_RL      10000   /* 10ms, the SoC can't keep up with 2ms */
+#define TOUCH_SHTIM                    0xa
+
+/**
+ * struct at91_adc_reg_desc - Various informations relative to registers
+ * @channel_base:	Base offset for the channel data registers
+ * @drdy_mask:		Mask of the DRDY field in the relevant registers
+			(Interruptions registers mostly)
+ * @status_register:	Offset of the Interrupt Status Register
+ * @trigger_register:	Offset of the Trigger setup register
+ * @mr_prescal_mask:	Mask of the PRESCAL field in the adc MR register
+ * @mr_startup_mask:	Mask of the STARTUP field in the adc MR register
+ */
+struct at91_adc_reg_desc {
+	u8	channel_base;
+	u32	drdy_mask;
+	u8	status_register;
+	u8	trigger_register;
+	u32	mr_prescal_mask;
+	u32	mr_startup_mask;
+};
+
+struct at91_adc_caps {
+	bool	has_ts;		/* Support touch screen */
+	bool	has_tsmr;	/* only at91sam9x5, sama5d3 have TSMR reg */
+	/*
+	 * Numbers of sampling data will be averaged. Can be 0~3.
+	 * Hardware can average (2 ^ ts_filter_average) sample data.
+	 */
+	u8	ts_filter_average;
+	/* Pen Detection input pull-up resistor, can be 0~3 */
+	u8	ts_pen_detect_sensitivity;
+
+	/* startup time calculate function */
+	u32 (*calc_startup_ticks)(u32 startup_time, u32 adc_clk_khz);
+
+	u8	num_channels;
+	struct at91_adc_reg_desc registers;
+};
+
+struct at91_adc_state {
+	struct clk		*adc_clk;
+	u16			*buffer;
+	unsigned long		channels_mask;
+	struct clk		*clk;
+	bool			done;
+	int			irq;
+	u16			last_value;
+	int			chnb;
+	struct mutex		lock;
+	u8			num_channels;
+	void __iomem		*reg_base;
+	struct at91_adc_reg_desc *registers;
+	u32			startup_time;
+	u8			sample_hold_time;
+	bool			sleep_mode;
+	struct iio_trigger	**trig;
+	struct at91_adc_trigger	*trigger_list;
+	u32			trigger_number;
+	bool			use_external;
+	u32			vref_mv;
+	u32			res;		/* resolution used for convertions */
+	bool			low_res;	/* the resolution corresponds to the lowest one */
+	wait_queue_head_t	wq_data_avail;
+	struct at91_adc_caps	*caps;
+
+	/*
+	 * Following ADC channels are shared by touchscreen:
+	 *
+	 * CH0 -- Touch screen XP/UL
+	 * CH1 -- Touch screen XM/UR
+	 * CH2 -- Touch screen YP/LL
+	 * CH3 -- Touch screen YM/Sense
+	 * CH4 -- Touch screen LR(5-wire only)
+	 *
+	 * The bitfields below represents the reserved channel in the
+	 * touchscreen mode.
+	 */
+#define CHAN_MASK_TOUCHSCREEN_4WIRE	(0xf << 0)
+#define CHAN_MASK_TOUCHSCREEN_5WIRE	(0x1f << 0)
+	enum atmel_adc_ts_type	touchscreen_type;
+	struct input_dev	*ts_input;
+
+	u16			ts_sample_period_val;
+	u32			ts_pressure_threshold;
+	u16			ts_pendbc;
+
+	bool			ts_bufferedmeasure;
+	u32			ts_prev_absx;
+	u32			ts_prev_absy;
+};
+
+static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *idev = pf->indio_dev;
+	struct at91_adc_state *st = iio_priv(idev);
+	int i, j = 0;
+
+	for (i = 0; i < idev->masklength; i++) {
+		if (!test_bit(i, idev->active_scan_mask))
+			continue;
+		st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, i));
+		j++;
+	}
+
+	iio_push_to_buffers_with_timestamp(idev, st->buffer, pf->timestamp);
+
+	iio_trigger_notify_done(idev->trig);
+
+	/* Needed to ACK the DRDY interruption */
+	at91_adc_readl(st, AT91_ADC_LCDR);
+
+	enable_irq(st->irq);
+
+	return IRQ_HANDLED;
+}
+
+/* Handler for classic adc channel eoc trigger */
+static void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
+{
+	struct at91_adc_state *st = iio_priv(idev);
+
+	if (iio_buffer_enabled(idev)) {
+		disable_irq_nosync(irq);
+		iio_trigger_poll(idev->trig);
+	} else {
+		st->last_value = at91_adc_readl(st, AT91_ADC_CHAN(st, st->chnb));
+		st->done = true;
+		wake_up_interruptible(&st->wq_data_avail);
+	}
+}
+
+static int at91_ts_sample(struct at91_adc_state *st)
+{
+	unsigned int xscale, yscale, reg, z1, z2;
+	unsigned int x, y, pres, xpos, ypos;
+	unsigned int rxp = 1;
+	unsigned int factor = 1000;
+	struct iio_dev *idev = iio_priv_to_dev(st);
+
+	unsigned int xyz_mask_bits = st->res;
+	unsigned int xyz_mask = (1 << xyz_mask_bits) - 1;
+
+	/* calculate position */
+	/* x position = (x / xscale) * max, max = 2^MAX_POS_BITS - 1 */
+	reg = at91_adc_readl(st, AT91_ADC_TSXPOSR);
+	xpos = reg & xyz_mask;
+	x = (xpos << MAX_POS_BITS) - xpos;
+	xscale = (reg >> 16) & xyz_mask;
+	if (xscale == 0) {
+		dev_err(&idev->dev, "Error: xscale == 0!\n");
+		return -1;
+	}
+	x /= xscale;
+
+	/* y position = (y / yscale) * max, max = 2^MAX_POS_BITS - 1 */
+	reg = at91_adc_readl(st, AT91_ADC_TSYPOSR);
+	ypos = reg & xyz_mask;
+	y = (ypos << MAX_POS_BITS) - ypos;
+	yscale = (reg >> 16) & xyz_mask;
+	if (yscale == 0) {
+		dev_err(&idev->dev, "Error: yscale == 0!\n");
+		return -1;
+	}
+	y /= yscale;
+
+	/* calculate the pressure */
+	reg = at91_adc_readl(st, AT91_ADC_TSPRESSR);
+	z1 = reg & xyz_mask;
+	z2 = (reg >> 16) & xyz_mask;
+
+	if (z1 != 0)
+		pres = rxp * (x * factor / 1024) * (z2 * factor / z1 - factor)
+			/ factor;
+	else
+		pres = st->ts_pressure_threshold;	/* no pen contacted */
+
+	dev_dbg(&idev->dev, "xpos = %d, xscale = %d, ypos = %d, yscale = %d, z1 = %d, z2 = %d, press = %d\n",
+				xpos, xscale, ypos, yscale, z1, z2, pres);
+
+	if (pres < st->ts_pressure_threshold) {
+		dev_dbg(&idev->dev, "x = %d, y = %d, pressure = %d\n",
+					x, y, pres / factor);
+		input_report_abs(st->ts_input, ABS_X, x);
+		input_report_abs(st->ts_input, ABS_Y, y);
+		input_report_abs(st->ts_input, ABS_PRESSURE, pres);
+		input_report_key(st->ts_input, BTN_TOUCH, 1);
+		input_sync(st->ts_input);
+	} else {
+		dev_dbg(&idev->dev, "pressure too low: not reporting\n");
+	}
+
+	return 0;
+}
+
+static irqreturn_t at91_adc_rl_interrupt(int irq, void *private)
+{
+	struct iio_dev *idev = private;
+	struct at91_adc_state *st = iio_priv(idev);
+	u32 status = at91_adc_readl(st, st->registers->status_register);
+	unsigned int reg;
+
+	status &= at91_adc_readl(st, AT91_ADC_IMR);
+	if (status & GENMASK(st->num_channels - 1, 0))
+		handle_adc_eoc_trigger(irq, idev);
+
+	if (status & AT91RL_ADC_IER_PEN) {
+		/* Disabling pen debounce is required to get a NOPEN irq */
+		reg = at91_adc_readl(st, AT91_ADC_MR);
+		reg &= ~AT91_ADC_PENDBC;
+		at91_adc_writel(st, AT91_ADC_MR, reg);
+
+		at91_adc_writel(st, AT91_ADC_IDR, AT91RL_ADC_IER_PEN);
+		at91_adc_writel(st, AT91_ADC_IER, AT91RL_ADC_IER_NOPEN
+				| AT91_ADC_EOC(3));
+		/* Set up period trigger for sampling */
+		at91_adc_writel(st, st->registers->trigger_register,
+			AT91_ADC_TRGR_MOD_PERIOD_TRIG |
+			AT91_ADC_TRGR_TRGPER_(st->ts_sample_period_val));
+	} else if (status & AT91RL_ADC_IER_NOPEN) {
+		reg = at91_adc_readl(st, AT91_ADC_MR);
+		reg |= AT91_ADC_PENDBC_(st->ts_pendbc) & AT91_ADC_PENDBC;
+		at91_adc_writel(st, AT91_ADC_MR, reg);
+		at91_adc_writel(st, st->registers->trigger_register,
+			AT91_ADC_TRGR_NONE);
+
+		at91_adc_writel(st, AT91_ADC_IDR, AT91RL_ADC_IER_NOPEN
+				| AT91_ADC_EOC(3));
+		at91_adc_writel(st, AT91_ADC_IER, AT91RL_ADC_IER_PEN);
+		st->ts_bufferedmeasure = false;
+		input_report_key(st->ts_input, BTN_TOUCH, 0);
+		input_sync(st->ts_input);
+	} else if (status & AT91_ADC_EOC(3)) {
+		/* Conversion finished */
+		if (st->ts_bufferedmeasure) {
+			/*
+			 * Last measurement is always discarded, since it can
+			 * be erroneous.
+			 * Always report previous measurement
+			 */
+			input_report_abs(st->ts_input, ABS_X, st->ts_prev_absx);
+			input_report_abs(st->ts_input, ABS_Y, st->ts_prev_absy);
+			input_report_key(st->ts_input, BTN_TOUCH, 1);
+			input_sync(st->ts_input);
+		} else
+			st->ts_bufferedmeasure = true;
+
+		/* Now make new measurement */
+		st->ts_prev_absx = at91_adc_readl(st, AT91_ADC_CHAN(st, 3))
+				   << MAX_RLPOS_BITS;
+		st->ts_prev_absx /= at91_adc_readl(st, AT91_ADC_CHAN(st, 2));
+
+		st->ts_prev_absy = at91_adc_readl(st, AT91_ADC_CHAN(st, 1))
+				   << MAX_RLPOS_BITS;
+		st->ts_prev_absy /= at91_adc_readl(st, AT91_ADC_CHAN(st, 0));
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t at91_adc_9x5_interrupt(int irq, void *private)
+{
+	struct iio_dev *idev = private;
+	struct at91_adc_state *st = iio_priv(idev);
+	u32 status = at91_adc_readl(st, st->registers->status_register);
+	const uint32_t ts_data_irq_mask =
+		AT91_ADC_IER_XRDY |
+		AT91_ADC_IER_YRDY |
+		AT91_ADC_IER_PRDY;
+
+	if (status & GENMASK(st->num_channels - 1, 0))
+		handle_adc_eoc_trigger(irq, idev);
+
+	if (status & AT91_ADC_IER_PEN) {
+		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
+		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_NOPEN |
+			ts_data_irq_mask);
+		/* Set up period trigger for sampling */
+		at91_adc_writel(st, st->registers->trigger_register,
+			AT91_ADC_TRGR_MOD_PERIOD_TRIG |
+			AT91_ADC_TRGR_TRGPER_(st->ts_sample_period_val));
+	} else if (status & AT91_ADC_IER_NOPEN) {
+		at91_adc_writel(st, st->registers->trigger_register, 0);
+		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_NOPEN |
+			ts_data_irq_mask);
+		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
+
+		input_report_key(st->ts_input, BTN_TOUCH, 0);
+		input_sync(st->ts_input);
+	} else if ((status & ts_data_irq_mask) == ts_data_irq_mask) {
+		/* Now all touchscreen data is ready */
+
+		if (status & AT91_ADC_ISR_PENS) {
+			/* validate data by pen contact */
+			at91_ts_sample(st);
+		} else {
+			/* triggered by event that is no pen contact, just read
+			 * them to clean the interrupt and discard all.
+			 */
+			at91_adc_readl(st, AT91_ADC_TSXPOSR);
+			at91_adc_readl(st, AT91_ADC_TSYPOSR);
+			at91_adc_readl(st, AT91_ADC_TSPRESSR);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int at91_adc_channel_init(struct iio_dev *idev)
+{
+	struct at91_adc_state *st = iio_priv(idev);
+	struct iio_chan_spec *chan_array, *timestamp;
+	int bit, idx = 0;
+	unsigned long rsvd_mask = 0;
+
+	/* If touchscreen is enable, then reserve the adc channels */
+	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
+		rsvd_mask = CHAN_MASK_TOUCHSCREEN_4WIRE;
+	else if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_5WIRE)
+		rsvd_mask = CHAN_MASK_TOUCHSCREEN_5WIRE;
+
+	/* set up the channel mask to reserve touchscreen channels */
+	st->channels_mask &= ~rsvd_mask;
+
+	idev->num_channels = bitmap_weight(&st->channels_mask,
+					   st->num_channels) + 1;
+
+	chan_array = devm_kzalloc(&idev->dev,
+				  ((idev->num_channels + 1) *
+					sizeof(struct iio_chan_spec)),
+				  GFP_KERNEL);
+
+	if (!chan_array)
+		return -ENOMEM;
+
+	for_each_set_bit(bit, &st->channels_mask, st->num_channels) {
+		struct iio_chan_spec *chan = chan_array + idx;
+
+		chan->type = IIO_VOLTAGE;
+		chan->indexed = 1;
+		chan->channel = bit;
+		chan->scan_index = idx;
+		chan->scan_type.sign = 'u';
+		chan->scan_type.realbits = st->res;
+		chan->scan_type.storagebits = 16;
+		chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
+		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
+		idx++;
+	}
+	timestamp = chan_array + idx;
+
+	timestamp->type = IIO_TIMESTAMP;
+	timestamp->channel = -1;
+	timestamp->scan_index = idx;
+	timestamp->scan_type.sign = 's';
+	timestamp->scan_type.realbits = 64;
+	timestamp->scan_type.storagebits = 64;
+
+	idev->channels = chan_array;
+	return idev->num_channels;
+}
+
+static int at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
+					     struct at91_adc_trigger *triggers,
+					     const char *trigger_name)
+{
+	struct at91_adc_state *st = iio_priv(idev);
+	int i;
+
+	for (i = 0; i < st->trigger_number; i++) {
+		char *name = kasprintf(GFP_KERNEL,
+				"%s-dev%d-%s",
+				idev->name,
+				idev->id,
+				triggers[i].name);
+		if (!name)
+			return -ENOMEM;
+
+		if (strcmp(trigger_name, name) == 0) {
+			kfree(name);
+			if (triggers[i].value == 0)
+				return -EINVAL;
+			return triggers[i].value;
+		}
+
+		kfree(name);
+	}
+
+	return -EINVAL;
+}
+
+static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
+{
+	struct iio_dev *idev = iio_trigger_get_drvdata(trig);
+	struct at91_adc_state *st = iio_priv(idev);
+	struct at91_adc_reg_desc *reg = st->registers;
+	u32 status = at91_adc_readl(st, reg->trigger_register);
+	int value;
+	u8 bit;
+
+	value = at91_adc_get_trigger_value_by_name(idev,
+						   st->trigger_list,
+						   idev->trig->name);
+	if (value < 0)
+		return value;
+
+	if (state) {
+		st->buffer = kmalloc(idev->scan_bytes, GFP_KERNEL);
+		if (st->buffer == NULL)
+			return -ENOMEM;
+
+		at91_adc_writel(st, reg->trigger_register,
+				status | value);
+
+		for_each_set_bit(bit, idev->active_scan_mask,
+				 st->num_channels) {
+			struct iio_chan_spec const *chan = idev->channels + bit;
+			at91_adc_writel(st, AT91_ADC_CHER,
+					AT91_ADC_CH(chan->channel));
+		}
+
+		at91_adc_writel(st, AT91_ADC_IER, reg->drdy_mask);
+
+	} else {
+		at91_adc_writel(st, AT91_ADC_IDR, reg->drdy_mask);
+
+		at91_adc_writel(st, reg->trigger_register,
+				status & ~value);
+
+		for_each_set_bit(bit, idev->active_scan_mask,
+				 st->num_channels) {
+			struct iio_chan_spec const *chan = idev->channels + bit;
+			at91_adc_writel(st, AT91_ADC_CHDR,
+					AT91_ADC_CH(chan->channel));
+		}
+		kfree(st->buffer);
+	}
+
+	return 0;
+}
+
+static const struct iio_trigger_ops at91_adc_trigger_ops = {
+	.owner = THIS_MODULE,
+	.set_trigger_state = &at91_adc_configure_trigger,
+};
+
+static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *idev,
+						     struct at91_adc_trigger *trigger)
+{
+	struct iio_trigger *trig;
+	int ret;
+
+	trig = iio_trigger_alloc("%s-dev%d-%s", idev->name,
+				 idev->id, trigger->name);
+	if (trig == NULL)
+		return NULL;
+
+	trig->dev.parent = idev->dev.parent;
+	iio_trigger_set_drvdata(trig, idev);
+	trig->ops = &at91_adc_trigger_ops;
+
+	ret = iio_trigger_register(trig);
+	if (ret)
+		return NULL;
+
+	return trig;
+}
+
+static int at91_adc_trigger_init(struct iio_dev *idev)
+{
+	struct at91_adc_state *st = iio_priv(idev);
+	int i, ret;
+
+	st->trig = devm_kzalloc(&idev->dev,
+				st->trigger_number * sizeof(*st->trig),
+				GFP_KERNEL);
+
+	if (st->trig == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	for (i = 0; i < st->trigger_number; i++) {
+		if (st->trigger_list[i].is_external && !(st->use_external))
+			continue;
+
+		st->trig[i] = at91_adc_allocate_trigger(idev,
+							st->trigger_list + i);
+		if (st->trig[i] == NULL) {
+			dev_err(&idev->dev,
+				"Could not allocate trigger %d\n", i);
+			ret = -ENOMEM;
+			goto error_trigger;
+		}
+	}
+
+	return 0;
+
+error_trigger:
+	for (i--; i >= 0; i--) {
+		iio_trigger_unregister(st->trig[i]);
+		iio_trigger_free(st->trig[i]);
+	}
+error_ret:
+	return ret;
+}
+
+static void at91_adc_trigger_remove(struct iio_dev *idev)
+{
+	struct at91_adc_state *st = iio_priv(idev);
+	int i;
+
+	for (i = 0; i < st->trigger_number; i++) {
+		iio_trigger_unregister(st->trig[i]);
+		iio_trigger_free(st->trig[i]);
+	}
+}
+
+static int at91_adc_buffer_init(struct iio_dev *idev)
+{
+	return iio_triggered_buffer_setup(idev, &iio_pollfunc_store_time,
+		&at91_adc_trigger_handler, NULL);
+}
+
+static void at91_adc_buffer_remove(struct iio_dev *idev)
+{
+	iio_triggered_buffer_cleanup(idev);
+}
+
+static int at91_adc_read_raw(struct iio_dev *idev,
+			     struct iio_chan_spec const *chan,
+			     int *val, int *val2, long mask)
+{
+	struct at91_adc_state *st = iio_priv(idev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&st->lock);
+
+		st->chnb = chan->channel;
+		at91_adc_writel(st, AT91_ADC_CHER,
+				AT91_ADC_CH(chan->channel));
+		at91_adc_writel(st, AT91_ADC_IER, BIT(chan->channel));
+		at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_START);
+
+		ret = wait_event_interruptible_timeout(st->wq_data_avail,
+						       st->done,
+						       msecs_to_jiffies(1000));
+		if (ret == 0)
+			ret = -ETIMEDOUT;
+		if (ret < 0) {
+			mutex_unlock(&st->lock);
+			return ret;
+		}
+
+		*val = st->last_value;
+
+		at91_adc_writel(st, AT91_ADC_CHDR,
+				AT91_ADC_CH(chan->channel));
+		at91_adc_writel(st, AT91_ADC_IDR, BIT(chan->channel));
+
+		st->last_value = 0;
+		st->done = false;
+		mutex_unlock(&st->lock);
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		*val = st->vref_mv;
+		*val2 = chan->scan_type.realbits;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	default:
+		break;
+	}
+	return -EINVAL;
+}
+
+static int at91_adc_of_get_resolution(struct at91_adc_state *st,
+				      struct platform_device *pdev)
+{
+	struct iio_dev *idev = iio_priv_to_dev(st);
+	struct device_node *np = pdev->dev.of_node;
+	int count, i, ret = 0;
+	char *res_name, *s;
+	u32 *resolutions;
+
+	count = of_property_count_strings(np, "atmel,adc-res-names");
+	if (count < 2) {
+		dev_err(&idev->dev, "You must specified at least two resolution names for "
+				    "adc-res-names property in the DT\n");
+		return count;
+	}
+
+	resolutions = kmalloc(count * sizeof(*resolutions), GFP_KERNEL);
+	if (!resolutions)
+		return -ENOMEM;
+
+	if (of_property_read_u32_array(np, "atmel,adc-res", resolutions, count)) {
+		dev_err(&idev->dev, "Missing adc-res property in the DT.\n");
+		ret = -ENODEV;
+		goto ret;
+	}
+
+	if (of_property_read_string(np, "atmel,adc-use-res", (const char **)&res_name))
+		res_name = "highres";
+
+	for (i = 0; i < count; i++) {
+		if (of_property_read_string_index(np, "atmel,adc-res-names", i, (const char **)&s))
+			continue;
+
+		if (strcmp(res_name, s))
+			continue;
+
+		st->res = resolutions[i];
+		if (!strcmp(res_name, "lowres"))
+			st->low_res = true;
+		else
+			st->low_res = false;
+
+		dev_info(&idev->dev, "Resolution used: %u bits\n", st->res);
+		goto ret;
+	}
+
+	dev_err(&idev->dev, "There is no resolution for %s\n", res_name);
+
+ret:
+	kfree(resolutions);
+	return ret;
+}
+
+static u32 calc_startup_ticks_9260(u32 startup_time, u32 adc_clk_khz)
+{
+	/*
+	 * Number of ticks needed to cover the startup time of the ADC
+	 * as defined in the electrical characteristics of the board,
+	 * divided by 8. The formula thus is :
+	 *   Startup Time = (ticks + 1) * 8 / ADC Clock
+	 */
+	return round_up((startup_time * adc_clk_khz / 1000) - 1, 8) / 8;
+}
+
+static u32 calc_startup_ticks_9x5(u32 startup_time, u32 adc_clk_khz)
+{
+	/*
+	 * For sama5d3x and at91sam9x5, the formula changes to:
+	 * Startup Time = <lookup_table_value> / ADC Clock
+	 */
+	const int startup_lookup[] = {
+		0  , 8  , 16 , 24 ,
+		64 , 80 , 96 , 112,
+		512, 576, 640, 704,
+		768, 832, 896, 960
+		};
+	int i, size = ARRAY_SIZE(startup_lookup);
+	unsigned int ticks;
+
+	ticks = startup_time * adc_clk_khz / 1000;
+	for (i = 0; i < size; i++)
+		if (ticks < startup_lookup[i])
+			break;
+
+	ticks = i;
+	if (ticks == size)
+		/* Reach the end of lookup table */
+		ticks = size - 1;
+
+	return ticks;
+}
+
+static const struct of_device_id at91_adc_dt_ids[];
+
+static int at91_adc_probe_dt_ts(struct device_node *node,
+	struct at91_adc_state *st, struct device *dev)
+{
+	int ret;
+	u32 prop;
+
+	ret = of_property_read_u32(node, "atmel,adc-ts-wires", &prop);
+	if (ret) {
+		dev_info(dev, "ADC Touch screen is disabled.\n");
+		return 0;
+	}
+
+	switch (prop) {
+	case 4:
+	case 5:
+		st->touchscreen_type = prop;
+		break;
+	default:
+		dev_err(dev, "Unsupported number of touchscreen wires (%d). Should be 4 or 5.\n", prop);
+		return -EINVAL;
+	}
+
+	if (!st->caps->has_tsmr)
+		return 0;
+	prop = 0;
+	of_property_read_u32(node, "atmel,adc-ts-pressure-threshold", &prop);
+	st->ts_pressure_threshold = prop;
+	if (st->ts_pressure_threshold) {
+		return 0;
+	} else {
+		dev_err(dev, "Invalid pressure threshold for the touchscreen\n");
+		return -EINVAL;
+	}
+}
+
+static int at91_adc_probe_dt(struct at91_adc_state *st,
+			     struct platform_device *pdev)
+{
+	struct iio_dev *idev = iio_priv_to_dev(st);
+	struct device_node *node = pdev->dev.of_node;
+	struct device_node *trig_node;
+	int i = 0, ret;
+	u32 prop;
+
+	if (!node)
+		return -EINVAL;
+
+	st->caps = (struct at91_adc_caps *)
+		of_match_device(at91_adc_dt_ids, &pdev->dev)->data;
+
+	st->use_external = of_property_read_bool(node, "atmel,adc-use-external-triggers");
+
+	if (of_property_read_u32(node, "atmel,adc-channels-used", &prop)) {
+		dev_err(&idev->dev, "Missing adc-channels-used property in the DT.\n");
+		ret = -EINVAL;
+		goto error_ret;
+	}
+	st->channels_mask = prop;
+
+	st->sleep_mode = of_property_read_bool(node, "atmel,adc-sleep-mode");
+
+	if (of_property_read_u32(node, "atmel,adc-startup-time", &prop)) {
+		dev_err(&idev->dev, "Missing adc-startup-time property in the DT.\n");
+		ret = -EINVAL;
+		goto error_ret;
+	}
+	st->startup_time = prop;
+
+	prop = 0;
+	of_property_read_u32(node, "atmel,adc-sample-hold-time", &prop);
+	st->sample_hold_time = prop;
+
+	if (of_property_read_u32(node, "atmel,adc-vref", &prop)) {
+		dev_err(&idev->dev, "Missing adc-vref property in the DT.\n");
+		ret = -EINVAL;
+		goto error_ret;
+	}
+	st->vref_mv = prop;
+
+	ret = at91_adc_of_get_resolution(st, pdev);
+	if (ret)
+		goto error_ret;
+
+	st->registers = &st->caps->registers;
+	st->num_channels = st->caps->num_channels;
+	st->trigger_number = of_get_child_count(node);
+	st->trigger_list = devm_kzalloc(&idev->dev, st->trigger_number *
+					sizeof(struct at91_adc_trigger),
+					GFP_KERNEL);
+	if (!st->trigger_list) {
+		dev_err(&idev->dev, "Could not allocate trigger list memory.\n");
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	for_each_child_of_node(node, trig_node) {
+		struct at91_adc_trigger *trig = st->trigger_list + i;
+		const char *name;
+
+		if (of_property_read_string(trig_node, "trigger-name", &name)) {
+			dev_err(&idev->dev, "Missing trigger-name property in the DT.\n");
+			ret = -EINVAL;
+			goto error_ret;
+		}
+	        trig->name = name;
+
+		if (of_property_read_u32(trig_node, "trigger-value", &prop)) {
+			dev_err(&idev->dev, "Missing trigger-value property in the DT.\n");
+			ret = -EINVAL;
+			goto error_ret;
+		}
+	        trig->value = prop;
+		trig->is_external = of_property_read_bool(trig_node, "trigger-external");
+		i++;
+	}
+
+	/* Check if touchscreen is supported. */
+	if (st->caps->has_ts)
+		return at91_adc_probe_dt_ts(node, st, &idev->dev);
+	else
+		dev_info(&idev->dev, "not support touchscreen in the adc compatible string.\n");
+
+	return 0;
+
+error_ret:
+	return ret;
+}
+
+static int at91_adc_probe_pdata(struct at91_adc_state *st,
+				struct platform_device *pdev)
+{
+	struct at91_adc_data *pdata = pdev->dev.platform_data;
+
+	if (!pdata)
+		return -EINVAL;
+
+	st->caps = (struct at91_adc_caps *)
+			platform_get_device_id(pdev)->driver_data;
+
+	st->use_external = pdata->use_external_triggers;
+	st->vref_mv = pdata->vref;
+	st->channels_mask = pdata->channels_used;
+	st->num_channels = st->caps->num_channels;
+	st->startup_time = pdata->startup_time;
+	st->trigger_number = pdata->trigger_number;
+	st->trigger_list = pdata->trigger_list;
+	st->registers = &st->caps->registers;
+	st->touchscreen_type = pdata->touchscreen_type;
+
+	return 0;
+}
+
+static const struct iio_info at91_adc_info = {
+	.driver_module = THIS_MODULE,
+	.read_raw = &at91_adc_read_raw,
+};
+
+/* Touchscreen related functions */
+static int atmel_ts_open(struct input_dev *dev)
+{
+	struct at91_adc_state *st = input_get_drvdata(dev);
+
+	if (st->caps->has_tsmr)
+		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
+	else
+		at91_adc_writel(st, AT91_ADC_IER, AT91RL_ADC_IER_PEN);
+	return 0;
+}
+
+static void atmel_ts_close(struct input_dev *dev)
+{
+	struct at91_adc_state *st = input_get_drvdata(dev);
+
+	if (st->caps->has_tsmr)
+		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
+	else
+		at91_adc_writel(st, AT91_ADC_IDR, AT91RL_ADC_IER_PEN);
+}
+
+static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
+{
+	u32 reg = 0;
+	int i = 0;
+
+	/* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid
+	 * pen detect noise.
+	 * The formula is : Pen Detect Debounce Time = (2 ^ pendbc) / ADCClock
+	 */
+	st->ts_pendbc = round_up(TOUCH_PEN_DETECT_DEBOUNCE_US * adc_clk_khz /
+				 1000, 1);
+
+	while (st->ts_pendbc >> ++i)
+		;	/* Empty! Find the shift offset */
+	if (abs(st->ts_pendbc - (1 << i)) < abs(st->ts_pendbc - (1 << (i - 1))))
+		st->ts_pendbc = i;
+	else
+		st->ts_pendbc = i - 1;
+
+	if (!st->caps->has_tsmr) {
+		reg = at91_adc_readl(st, AT91_ADC_MR);
+		reg |= AT91_ADC_TSAMOD_TS_ONLY_MODE | AT91_ADC_PENDET;
+
+		reg |= AT91_ADC_PENDBC_(st->ts_pendbc) & AT91_ADC_PENDBC;
+		at91_adc_writel(st, AT91_ADC_MR, reg);
+
+		reg = AT91_ADC_TSR_SHTIM_(TOUCH_SHTIM) & AT91_ADC_TSR_SHTIM;
+		at91_adc_writel(st, AT91_ADC_TSR, reg);
+
+		st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US_RL *
+						    adc_clk_khz / 1000) - 1, 1);
+
+		return 0;
+	}
+
+	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
+		reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS;
+	else
+		reg = AT91_ADC_TSMR_TSMODE_5WIRE;
+
+	reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average)
+	       & AT91_ADC_TSMR_TSAV;
+	reg |= AT91_ADC_TSMR_PENDBC_(st->ts_pendbc) & AT91_ADC_TSMR_PENDBC;
+	reg |= AT91_ADC_TSMR_NOTSDMA;
+	reg |= AT91_ADC_TSMR_PENDET_ENA;
+	reg |= 0x03 << 8;	/* TSFREQ, needs to be bigger than TSAV */
+
+	at91_adc_writel(st, AT91_ADC_TSMR, reg);
+
+	/* Change adc internal resistor value for better pen detection,
+	 * default value is 100 kOhm.
+	 * 0 = 200 kOhm, 1 = 150 kOhm, 2 = 100 kOhm, 3 = 50 kOhm
+	 * option only available on ES2 and higher
+	 */
+	at91_adc_writel(st, AT91_ADC_ACR, st->caps->ts_pen_detect_sensitivity
+			& AT91_ADC_ACR_PENDETSENS);
+
+	/* Sample Period Time = (TRGPER + 1) / ADCClock */
+	st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US *
+			adc_clk_khz / 1000) - 1, 1);
+
+	return 0;
+}
+
+static int at91_ts_register(struct at91_adc_state *st,
+		struct platform_device *pdev)
+{
+	struct input_dev *input;
+	struct iio_dev *idev = iio_priv_to_dev(st);
+	int ret;
+
+	input = input_allocate_device();
+	if (!input) {
+		dev_err(&idev->dev, "Failed to allocate TS device!\n");
+		return -ENOMEM;
+	}
+
+	input->name = DRIVER_NAME;
+	input->id.bustype = BUS_HOST;
+	input->dev.parent = &pdev->dev;
+	input->open = atmel_ts_open;
+	input->close = atmel_ts_close;
+
+	__set_bit(EV_ABS, input->evbit);
+	__set_bit(EV_KEY, input->evbit);
+	__set_bit(BTN_TOUCH, input->keybit);
+	if (st->caps->has_tsmr) {
+		input_set_abs_params(input, ABS_X, 0, (1 << MAX_POS_BITS) - 1,
+				     0, 0);
+		input_set_abs_params(input, ABS_Y, 0, (1 << MAX_POS_BITS) - 1,
+				     0, 0);
+		input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0);
+	} else {
+		if (st->touchscreen_type != ATMEL_ADC_TOUCHSCREEN_4WIRE) {
+			dev_err(&pdev->dev,
+				"This touchscreen controller only support 4 wires\n");
+			ret = -EINVAL;
+			goto err;
+		}
+
+		input_set_abs_params(input, ABS_X, 0, (1 << MAX_RLPOS_BITS) - 1,
+				     0, 0);
+		input_set_abs_params(input, ABS_Y, 0, (1 << MAX_RLPOS_BITS) - 1,
+				     0, 0);
+	}
+
+	st->ts_input = input;
+	input_set_drvdata(input, st);
+
+	ret = input_register_device(input);
+	if (ret)
+		goto err;
+
+	return ret;
+
+err:
+	input_free_device(st->ts_input);
+	return ret;
+}
+
+static void at91_ts_unregister(struct at91_adc_state *st)
+{
+	input_unregister_device(st->ts_input);
+}
+
+static int at91_adc_probe(struct platform_device *pdev)
+{
+	unsigned int prsc, mstrclk, ticks, adc_clk, adc_clk_khz, shtim;
+	int ret;
+	struct iio_dev *idev;
+	struct at91_adc_state *st;
+	struct resource *res;
+	u32 reg;
+
+	idev = devm_iio_device_alloc(&pdev->dev, sizeof(struct at91_adc_state));
+	if (!idev)
+		return -ENOMEM;
+
+	st = iio_priv(idev);
+
+	if (pdev->dev.of_node)
+		ret = at91_adc_probe_dt(st, pdev);
+	else
+		ret = at91_adc_probe_pdata(st, pdev);
+
+	if (ret) {
+		dev_err(&pdev->dev, "No platform data available.\n");
+		return -EINVAL;
+	}
+
+	platform_set_drvdata(pdev, idev);
+
+	idev->dev.parent = &pdev->dev;
+	idev->name = dev_name(&pdev->dev);
+	idev->modes = INDIO_DIRECT_MODE;
+	idev->info = &at91_adc_info;
+
+	st->irq = platform_get_irq(pdev, 0);
+	if (st->irq < 0) {
+		dev_err(&pdev->dev, "No IRQ ID is designated\n");
+		return -ENODEV;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	st->reg_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(st->reg_base)) {
+		return PTR_ERR(st->reg_base);
+	}
+
+	/*
+	 * Disable all IRQs before setting up the handler
+	 */
+	at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
+	at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
+
+	if (st->caps->has_tsmr)
+		ret = request_irq(st->irq, at91_adc_9x5_interrupt, 0,
+				  pdev->dev.driver->name, idev);
+	else
+		ret = request_irq(st->irq, at91_adc_rl_interrupt, 0,
+				  pdev->dev.driver->name, idev);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to allocate IRQ.\n");
+		return ret;
+	}
+
+	st->clk = devm_clk_get(&pdev->dev, "adc_clk");
+	if (IS_ERR(st->clk)) {
+		dev_err(&pdev->dev, "Failed to get the clock.\n");
+		ret = PTR_ERR(st->clk);
+		goto error_free_irq;
+	}
+
+	ret = clk_prepare_enable(st->clk);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"Could not prepare or enable the clock.\n");
+		goto error_free_irq;
+	}
+
+	st->adc_clk = devm_clk_get(&pdev->dev, "adc_op_clk");
+	if (IS_ERR(st->adc_clk)) {
+		dev_err(&pdev->dev, "Failed to get the ADC clock.\n");
+		ret = PTR_ERR(st->adc_clk);
+		goto error_disable_clk;
+	}
+
+	ret = clk_prepare_enable(st->adc_clk);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"Could not prepare or enable the ADC clock.\n");
+		goto error_disable_clk;
+	}
+
+	/*
+	 * Prescaler rate computation using the formula from the Atmel's
+	 * datasheet : ADC Clock = MCK / ((Prescaler + 1) * 2), ADC Clock being
+	 * specified by the electrical characteristics of the board.
+	 */
+	mstrclk = clk_get_rate(st->clk);
+	adc_clk = clk_get_rate(st->adc_clk);
+	adc_clk_khz = adc_clk / 1000;
+
+	dev_dbg(&pdev->dev, "Master clock is set as: %d Hz, adc_clk should set as: %d Hz\n",
+		mstrclk, adc_clk);
+
+	prsc = (mstrclk / (2 * adc_clk)) - 1;
+
+	if (!st->startup_time) {
+		dev_err(&pdev->dev, "No startup time available.\n");
+		ret = -EINVAL;
+		goto error_disable_adc_clk;
+	}
+	ticks = (*st->caps->calc_startup_ticks)(st->startup_time, adc_clk_khz);
+
+	/*
+	 * a minimal Sample and Hold Time is necessary for the ADC to guarantee
+	 * the best converted final value between two channels selection
+	 * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock
+	 */
+	if (st->sample_hold_time > 0)
+		shtim = round_up((st->sample_hold_time * adc_clk_khz / 1000)
+				 - 1, 1);
+	else
+		shtim = 0;
+
+	reg = AT91_ADC_PRESCAL_(prsc) & st->registers->mr_prescal_mask;
+	reg |= AT91_ADC_STARTUP_(ticks) & st->registers->mr_startup_mask;
+	if (st->low_res)
+		reg |= AT91_ADC_LOWRES;
+	if (st->sleep_mode)
+		reg |= AT91_ADC_SLEEP;
+	reg |= AT91_ADC_SHTIM_(shtim) & AT91_ADC_SHTIM;
+	at91_adc_writel(st, AT91_ADC_MR, reg);
+
+	/* Setup the ADC channels available on the board */
+	ret = at91_adc_channel_init(idev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Couldn't initialize the channels.\n");
+		goto error_disable_adc_clk;
+	}
+
+	init_waitqueue_head(&st->wq_data_avail);
+	mutex_init(&st->lock);
+
+	/*
+	 * Since touch screen will set trigger register as period trigger. So
+	 * when touch screen is enabled, then we have to disable hardware
+	 * trigger for classic adc.
+	 */
+	if (!st->touchscreen_type) {
+		ret = at91_adc_buffer_init(idev);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
+			goto error_disable_adc_clk;
+		}
+
+		ret = at91_adc_trigger_init(idev);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
+			at91_adc_buffer_remove(idev);
+			goto error_disable_adc_clk;
+		}
+	} else {
+		ret = at91_ts_register(st, pdev);
+		if (ret)
+			goto error_disable_adc_clk;
+
+		at91_ts_hw_init(st, adc_clk_khz);
+	}
+
+	ret = iio_device_register(idev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Couldn't register the device.\n");
+		goto error_iio_device_register;
+	}
+
+	return 0;
+
+error_iio_device_register:
+	if (!st->touchscreen_type) {
+		at91_adc_trigger_remove(idev);
+		at91_adc_buffer_remove(idev);
+	} else {
+		at91_ts_unregister(st);
+	}
+error_disable_adc_clk:
+	clk_disable_unprepare(st->adc_clk);
+error_disable_clk:
+	clk_disable_unprepare(st->clk);
+error_free_irq:
+	free_irq(st->irq, idev);
+	return ret;
+}
+
+static int at91_adc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *idev = platform_get_drvdata(pdev);
+	struct at91_adc_state *st = iio_priv(idev);
+
+	iio_device_unregister(idev);
+	if (!st->touchscreen_type) {
+		at91_adc_trigger_remove(idev);
+		at91_adc_buffer_remove(idev);
+	} else {
+		at91_ts_unregister(st);
+	}
+	clk_disable_unprepare(st->adc_clk);
+	clk_disable_unprepare(st->clk);
+	free_irq(st->irq, idev);
+
+	return 0;
+}
+
+static struct at91_adc_caps at91sam9260_caps = {
+	.calc_startup_ticks = calc_startup_ticks_9260,
+	.num_channels = 4,
+	.registers = {
+		.channel_base = AT91_ADC_CHR(0),
+		.drdy_mask = AT91_ADC_DRDY,
+		.status_register = AT91_ADC_SR,
+		.trigger_register = AT91_ADC_TRGR_9260,
+		.mr_prescal_mask = AT91_ADC_PRESCAL_9260,
+		.mr_startup_mask = AT91_ADC_STARTUP_9260,
+	},
+};
+
+static struct at91_adc_caps at91sam9rl_caps = {
+	.has_ts = true,
+	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
+	.num_channels = 6,
+	.registers = {
+		.channel_base = AT91_ADC_CHR(0),
+		.drdy_mask = AT91_ADC_DRDY,
+		.status_register = AT91_ADC_SR,
+		.trigger_register = AT91_ADC_TRGR_9G45,
+		.mr_prescal_mask = AT91_ADC_PRESCAL_9260,
+		.mr_startup_mask = AT91_ADC_STARTUP_9G45,
+	},
+};
+
+static struct at91_adc_caps at91sam9g45_caps = {
+	.has_ts = true,
+	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
+	.num_channels = 8,
+	.registers = {
+		.channel_base = AT91_ADC_CHR(0),
+		.drdy_mask = AT91_ADC_DRDY,
+		.status_register = AT91_ADC_SR,
+		.trigger_register = AT91_ADC_TRGR_9G45,
+		.mr_prescal_mask = AT91_ADC_PRESCAL_9G45,
+		.mr_startup_mask = AT91_ADC_STARTUP_9G45,
+	},
+};
+
+static struct at91_adc_caps at91sam9x5_caps = {
+	.has_ts = true,
+	.has_tsmr = true,
+	.ts_filter_average = 3,
+	.ts_pen_detect_sensitivity = 2,
+	.calc_startup_ticks = calc_startup_ticks_9x5,
+	.num_channels = 12,
+	.registers = {
+		.channel_base = AT91_ADC_CDR0_9X5,
+		.drdy_mask = AT91_ADC_SR_DRDY_9X5,
+		.status_register = AT91_ADC_SR_9X5,
+		.trigger_register = AT91_ADC_TRGR_9X5,
+		/* prescal mask is same as 9G45 */
+		.mr_prescal_mask = AT91_ADC_PRESCAL_9G45,
+		.mr_startup_mask = AT91_ADC_STARTUP_9X5,
+	},
+};
+
+static const struct of_device_id at91_adc_dt_ids[] = {
+	{ .compatible = "atmel,at91sam9260-adc", .data = &at91sam9260_caps },
+	{ .compatible = "atmel,at91sam9rl-adc", .data = &at91sam9rl_caps },
+	{ .compatible = "atmel,at91sam9g45-adc", .data = &at91sam9g45_caps },
+	{ .compatible = "atmel,at91sam9x5-adc", .data = &at91sam9x5_caps },
+	{},
+};
+MODULE_DEVICE_TABLE(of, at91_adc_dt_ids);
+
+static const struct platform_device_id at91_adc_ids[] = {
+	{
+		.name = "at91sam9260-adc",
+		.driver_data = (unsigned long)&at91sam9260_caps,
+	}, {
+		.name = "at91sam9rl-adc",
+		.driver_data = (unsigned long)&at91sam9rl_caps,
+	}, {
+		.name = "at91sam9g45-adc",
+		.driver_data = (unsigned long)&at91sam9g45_caps,
+	}, {
+		.name = "at91sam9x5-adc",
+		.driver_data = (unsigned long)&at91sam9x5_caps,
+	}, {
+		/* terminator */
+	}
+};
+MODULE_DEVICE_TABLE(platform, at91_adc_ids);
+
+static struct platform_driver at91_adc_driver = {
+	.probe = at91_adc_probe,
+	.remove = at91_adc_remove,
+	.id_table = at91_adc_ids,
+	.driver = {
+		   .name = DRIVER_NAME,
+		   .of_match_table = of_match_ptr(at91_adc_dt_ids),
+	},
+};
+
+module_platform_driver(at91_adc_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Atmel AT91 ADC Driver");
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");