Re: [PATCH v3 1/5] iio:adc:at91_adc8xx: introduce new atmel adc driver

[Jonathan Cameron <jic23@kernel.org>]

On 14/01/16 15:38, Ludovic Desroches wrote:
> This driver supports the new version of the Atmel ADC device introduced
> with the SAMA5D2 SoC family.
> 
> Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
> Acked-by: Rob Herring <robh@kernel.org>
Looks good to me.  One totally trivial note inline (which I'm not even going
to bother changing whilst applying the patch - a good measure of how trivial ;)

Applied to the togreg branch of iio.git - initially pushed out as testing
for the autobuilders to play with it.

Thanks,

Jonathan
> ---
>  .../bindings/iio/adc/at91-sama5d2_adc.txt          |  28 ++
>  drivers/iio/adc/Kconfig                            |  11 +
>  drivers/iio/adc/Makefile                           |   1 +
>  drivers/iio/adc/at91-sama5d2_adc.c                 | 509 +++++++++++++++++++++
>  4 files changed, 549 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/at91-sama5d2_adc.txt
>  create mode 100644 drivers/iio/adc/at91-sama5d2_adc.c
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/at91-sama5d2_adc.txt b/Documentation/devicetree/bindings/iio/adc/at91-sama5d2_adc.txt
> new file mode 100644
> index 0000000..3223684
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/at91-sama5d2_adc.txt
> @@ -0,0 +1,28 @@
> +* AT91 SAMA5D2 Analog to Digital Converter (ADC)
> +
> +Required properties:
> +  - compatible: Should be "atmel,sama5d2-adc".
> +  - reg: Should contain ADC registers location and length.
> +  - interrupts: Should contain the IRQ line for the ADC.
> +  - clocks: phandle to device clock.
> +  - clock-names: Must be "adc_clk".
> +  - vref-supply: Supply used as reference for conversions.
> +  - vddana-supply: Supply for the adc device.
> +  - atmel,min-sample-rate-hz: Minimum sampling rate, it depends on SoC.
> +  - atmel,max-sample-rate-hz: Maximum sampling rate, it depends on SoC.
> +  - atmel,startup-time-ms: Startup time expressed in ms, it depends on SoC.
> +
> +Example:
> +
> +adc: adc@fc030000 {
> +	compatible = "atmel,sama5d2-adc";
> +	reg = <0xfc030000 0x100>;
> +	interrupts = <40 IRQ_TYPE_LEVEL_HIGH 7>;
> +	clocks = <&adc_clk>;
> +	clock-names = "adc_clk";
> +	atmel,min-sample-rate-hz = <200000>;
> +	atmel,max-sample-rate-hz = <20000000>;
> +	atmel,startup-time-ms = <4>;
> +	vddana-supply = <&vdd_3v3_lp_reg>;
> +	vref-supply = <&vdd_3v3_lp_reg>;
> +}
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 605ff42..f57b4ea 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -131,6 +131,17 @@ config AT91_ADC
>  	  To compile this driver as a module, choose M here: the module will be
>  	  called at91_adc.
>  
> +config AT91_SAMA5D2_ADC
> +	tristate "Atmel AT91 SAMA5D2 ADC"
> +	depends on ARCH_AT91
> +	depends on INPUT
> +	help
> +	  Say yes here to build support for Atmel SAMA5D2 ADC which is
> +	  available on SAMA5D2 SoC family.
> +
> +	  To compile this driver as a module, choose M here: the module will be
> +	  called at91-sama5d2_adc.
> +
>  config AXP288_ADC
>  	tristate "X-Powers AXP288 ADC driver"
>  	depends on MFD_AXP20X
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 6435780..fb57e12 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -14,6 +14,7 @@ obj-$(CONFIG_AD7793) += ad7793.o
>  obj-$(CONFIG_AD7887) += ad7887.o
>  obj-$(CONFIG_AD799X) += ad799x.o
>  obj-$(CONFIG_AT91_ADC) += at91_adc.o
> +obj-$(CONFIG_AT91_SAMA5D2_ADC) += at91-sama5d2_adc.o
>  obj-$(CONFIG_AXP288_ADC) += axp288_adc.o
>  obj-$(CONFIG_BERLIN2_ADC) += berlin2-adc.o
>  obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
> diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
> new file mode 100644
> index 0000000..ecb2d90
> --- /dev/null
> +++ b/drivers/iio/adc/at91-sama5d2_adc.c
> @@ -0,0 +1,509 @@
> +/*
> + * Atmel ADC driver for SAMA5D2 devices and compatible.
> + *
> + * Copyright (C) 2015 Atmel,
> + *               2015 Ludovic Desroches <ludovic.desroches@atmel.com>
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/sched.h>
> +#include <linux/wait.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/regulator/consumer.h>
> +
> +/* Control Register */
> +#define AT91_SAMA5D2_CR		0x00
> +/* Software Reset */
> +#define	AT91_SAMA5D2_CR_SWRST		BIT(0)
> +/* Start Conversion */
> +#define	AT91_SAMA5D2_CR_START		BIT(1)
> +/* Touchscreen Calibration */
> +#define	AT91_SAMA5D2_CR_TSCALIB		BIT(2)
> +/* Comparison Restart */
> +#define	AT91_SAMA5D2_CR_CMPRST		BIT(4)
> +
> +/* Mode Register */
> +#define AT91_SAMA5D2_MR		0x04
> +/* Trigger Selection */
> +#define	AT91_SAMA5D2_MR_TRGSEL(v)	((v) << 1)
> +/* ADTRG */
> +#define	AT91_SAMA5D2_MR_TRGSEL_TRIG0	0
> +/* TIOA0 */
> +#define	AT91_SAMA5D2_MR_TRGSEL_TRIG1	1
> +/* TIOA1 */
> +#define	AT91_SAMA5D2_MR_TRGSEL_TRIG2	2
> +/* TIOA2 */
> +#define	AT91_SAMA5D2_MR_TRGSEL_TRIG3	3
> +/* PWM event line 0 */
> +#define	AT91_SAMA5D2_MR_TRGSEL_TRIG4	4
> +/* PWM event line 1 */
> +#define	AT91_SAMA5D2_MR_TRGSEL_TRIG5	5
> +/* TIOA3 */
> +#define	AT91_SAMA5D2_MR_TRGSEL_TRIG6	6
> +/* RTCOUT0 */
> +#define	AT91_SAMA5D2_MR_TRGSEL_TRIG7	7
> +/* Sleep Mode */
> +#define	AT91_SAMA5D2_MR_SLEEP		BIT(5)
> +/* Fast Wake Up */
> +#define	AT91_SAMA5D2_MR_FWUP		BIT(6)
> +/* Prescaler Rate Selection */
> +#define	AT91_SAMA5D2_MR_PRESCAL(v)	((v) << AT91_SAMA5D2_MR_PRESCAL_OFFSET)
> +#define	AT91_SAMA5D2_MR_PRESCAL_OFFSET	8
> +#define	AT91_SAMA5D2_MR_PRESCAL_MAX	0xff
> +/* Startup Time */
> +#define	AT91_SAMA5D2_MR_STARTUP(v)	((v) << 16)
> +/* Analog Change */
> +#define	AT91_SAMA5D2_MR_ANACH		BIT(23)
> +/* Tracking Time */
> +#define	AT91_SAMA5D2_MR_TRACKTIM(v)	((v) << 24)
> +#define	AT91_SAMA5D2_MR_TRACKTIM_MAX	0xff
> +/* Transfer Time */
> +#define	AT91_SAMA5D2_MR_TRANSFER(v)	((v) << 28)
> +#define	AT91_SAMA5D2_MR_TRANSFER_MAX	0x3
> +/* Use Sequence Enable */
> +#define	AT91_SAMA5D2_MR_USEQ		BIT(31)
> +
> +/* Channel Sequence Register 1 */
> +#define AT91_SAMA5D2_SEQR1	0x08
> +/* Channel Sequence Register 2 */
> +#define AT91_SAMA5D2_SEQR2	0x0c
> +/* Channel Enable Register */
> +#define AT91_SAMA5D2_CHER	0x10
> +/* Channel Disable Register */
> +#define AT91_SAMA5D2_CHDR	0x14
> +/* Channel Status Register */
> +#define AT91_SAMA5D2_CHSR	0x18
> +/* Last Converted Data Register */
> +#define AT91_SAMA5D2_LCDR	0x20
> +/* Interrupt Enable Register */
> +#define AT91_SAMA5D2_IER		0x24
> +/* Interrupt Disable Register */
> +#define AT91_SAMA5D2_IDR		0x28
> +/* Interrupt Mask Register */
> +#define AT91_SAMA5D2_IMR		0x2c
> +/* Interrupt Status Register */
> +#define AT91_SAMA5D2_ISR		0x30
> +/* Last Channel Trigger Mode Register */
> +#define AT91_SAMA5D2_LCTMR	0x34
> +/* Last Channel Compare Window Register */
> +#define AT91_SAMA5D2_LCCWR	0x38
> +/* Overrun Status Register */
> +#define AT91_SAMA5D2_OVER	0x3c
> +/* Extended Mode Register */
> +#define AT91_SAMA5D2_EMR		0x40
> +/* Compare Window Register */
> +#define AT91_SAMA5D2_CWR		0x44
> +/* Channel Gain Register */
> +#define AT91_SAMA5D2_CGR		0x48
> +/* Channel Offset Register */
> +#define AT91_SAMA5D2_COR		0x4c
> +/* Channel Data Register 0 */
> +#define AT91_SAMA5D2_CDR0	0x50
> +/* Analog Control Register */
> +#define AT91_SAMA5D2_ACR		0x94
> +/* Touchscreen Mode Register */
> +#define AT91_SAMA5D2_TSMR	0xb0
> +/* Touchscreen X Position Register */
> +#define AT91_SAMA5D2_XPOSR	0xb4
> +/* Touchscreen Y Position Register */
> +#define AT91_SAMA5D2_YPOSR	0xb8
> +/* Touchscreen Pressure Register */
> +#define AT91_SAMA5D2_PRESSR	0xbc
> +/* Trigger Register */
> +#define AT91_SAMA5D2_TRGR	0xc0
> +/* Correction Select Register */
> +#define AT91_SAMA5D2_COSR	0xd0
> +/* Correction Value Register */
> +#define AT91_SAMA5D2_CVR		0xd4
> +/* Channel Error Correction Register */
> +#define AT91_SAMA5D2_CECR	0xd8
> +/* Write Protection Mode Register */
> +#define AT91_SAMA5D2_WPMR	0xe4
> +/* Write Protection Status Register */
> +#define AT91_SAMA5D2_WPSR	0xe8
> +/* Version Register */
> +#define AT91_SAMA5D2_VERSION	0xfc
> +
> +#define AT91_AT91_SAMA5D2_CHAN(num, addr)				\
> +	{								\
> +		.type = IIO_VOLTAGE,					\
> +		.channel = num,						\
> +		.address = addr,					\
> +		.scan_type = {						\
> +			.sign = 'u',					\
> +			.realbits = 12,					\
> +		},							\
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
> +		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
> +		.datasheet_name = "CH"#num,				\
> +		.indexed = 1,						\
> +	}
> +
> +#define at91_adc_readl(st, reg)		readl_relaxed(st->base + reg)
> +#define at91_adc_writel(st, reg, val)	writel_relaxed(val, st->base + reg)
> +
> +struct at91_adc_soc_info {
> +	unsigned			startup_time;
> +	unsigned			min_sample_rate;
> +	unsigned			max_sample_rate;
> +};
> +
> +struct at91_adc_state {
> +	void __iomem			*base;
> +	int				irq;
> +	struct clk			*per_clk;
> +	struct regulator		*reg;
> +	struct regulator		*vref;
> +	u32				vref_uv;
> +	const struct iio_chan_spec	*chan;
> +	bool				conversion_done;
> +	u32				conversion_value;
> +	struct at91_adc_soc_info	soc_info;
> +	wait_queue_head_t		wq_data_available;
> +	/*
> +	 * lock to prevent concurrent 'single conversion' requests through
> +	 * sysfs.
> +	 */
> +	struct mutex			lock;
> +};
> +
> +static const struct iio_chan_spec at91_adc_channels[] = {
> +	AT91_AT91_SAMA5D2_CHAN(0, 0x50),
> +	AT91_AT91_SAMA5D2_CHAN(1, 0x54),
> +	AT91_AT91_SAMA5D2_CHAN(2, 0x58),
> +	AT91_AT91_SAMA5D2_CHAN(3, 0x5c),
> +	AT91_AT91_SAMA5D2_CHAN(4, 0x60),
> +	AT91_AT91_SAMA5D2_CHAN(5, 0x64),
> +	AT91_AT91_SAMA5D2_CHAN(6, 0x68),
> +	AT91_AT91_SAMA5D2_CHAN(7, 0x6c),
> +	AT91_AT91_SAMA5D2_CHAN(8, 0x70),
> +	AT91_AT91_SAMA5D2_CHAN(9, 0x74),
> +	AT91_AT91_SAMA5D2_CHAN(10, 0x78),
> +	AT91_AT91_SAMA5D2_CHAN(11, 0x7c),
> +};
> +
> +static unsigned at91_adc_startup_time(unsigned startup_time_min,
> +				      unsigned adc_clk_khz)
> +{
> +	const unsigned startup_lookup[] = {
> +		  0,   8,  16,  24,
> +		 64,  80,  96, 112,
> +		512, 576, 640, 704,
> +		768, 832, 896, 960
> +		};
> +	unsigned ticks_min, i;
> +
> +	/*
> +	 * Since the adc frequency is checked before, there is no reason
> +	 * to not meet the startup time constraint.
> +	 */
> +
> +	ticks_min = startup_time_min * adc_clk_khz / 1000;
> +	for (i = 0; i < ARRAY_SIZE(startup_lookup); i++)
> +		if (startup_lookup[i] > ticks_min)
> +			break;
> +
> +	return i;
> +}
> +
> +static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
> +{
> +	struct iio_dev *indio_dev = iio_priv_to_dev(st);
> +	unsigned f_per, prescal, startup;
> +
> +	f_per = clk_get_rate(st->per_clk);
> +	prescal = (f_per / (2 * freq)) - 1;
> +
> +	startup = at91_adc_startup_time(st->soc_info.startup_time,
> +					freq / 1000);
> +
> +	at91_adc_writel(st, AT91_SAMA5D2_MR,
> +			AT91_SAMA5D2_MR_TRANSFER(2)
> +			| AT91_SAMA5D2_MR_STARTUP(startup)
> +			| AT91_SAMA5D2_MR_PRESCAL(prescal));
> +
> +	dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
> +		freq, startup, prescal);
> +}
> +
> +static unsigned at91_adc_get_sample_freq(struct at91_adc_state *st)
> +{
> +	unsigned f_adc, f_per = clk_get_rate(st->per_clk);
> +	unsigned mr, prescal;
> +
> +	mr = at91_adc_readl(st, AT91_SAMA5D2_MR);
> +	prescal = (mr >> AT91_SAMA5D2_MR_PRESCAL_OFFSET)
> +		  & AT91_SAMA5D2_MR_PRESCAL_MAX;
> +	f_adc = f_per / (2 * (prescal + 1));
> +
> +	return f_adc;
> +}
> +
> +static irqreturn_t at91_adc_interrupt(int irq, void *private)
> +{
> +	struct iio_dev *indio = private;
> +	struct at91_adc_state *st = iio_priv(indio);
> +	u32 status = at91_adc_readl(st, AT91_SAMA5D2_ISR);
> +	u32 imr = at91_adc_readl(st, AT91_SAMA5D2_IMR);
> +
> +	if (status & imr) {
> +		st->conversion_value = at91_adc_readl(st, st->chan->address);
> +		st->conversion_done = true;
> +		wake_up_interruptible(&st->wq_data_available);
> +		return IRQ_HANDLED;
> +	}
> +
> +	return IRQ_NONE;
> +}
> +
> +static int at91_adc_read_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int *val, int *val2, long mask)
> +{
> +	struct at91_adc_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		mutex_lock(&st->lock);
> +
> +		st->chan = chan;
> +
> +		at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
> +		at91_adc_writel(st, AT91_SAMA5D2_IER, BIT(chan->channel));
> +		at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_START);
> +
> +		ret = wait_event_interruptible_timeout(st->wq_data_available,
> +						       st->conversion_done,
> +						       msecs_to_jiffies(1000));
> +		if (ret == 0)
> +			ret = -ETIMEDOUT;
> +
> +		if (ret > 0) {
> +			*val = st->conversion_value;
> +			ret = IIO_VAL_INT;
> +			st->conversion_done = false;
> +		}
> +
> +		at91_adc_writel(st, AT91_SAMA5D2_IDR, BIT(chan->channel));
> +		at91_adc_writel(st, AT91_SAMA5D2_CHDR, BIT(chan->channel));
> +
> +		mutex_unlock(&st->lock);
> +		return ret;
> +
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = st->vref_uv / 1000;
> +		*val2 = chan->scan_type.realbits;
> +		return IIO_VAL_FRACTIONAL_LOG2;
> +
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		*val = at91_adc_get_sample_freq(st);
> +		return IIO_VAL_INT;
> +
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int at91_adc_write_raw(struct iio_dev *indio_dev,
> +			      struct iio_chan_spec const *chan,
> +			      int val, int val2, long mask)
> +{
> +	struct at91_adc_state *st = iio_priv(indio_dev);
> +
> +	if (mask != IIO_CHAN_INFO_SAMP_FREQ)
> +		return -EINVAL;
> +
> +	if (val < st->soc_info.min_sample_rate ||
> +	    val > st->soc_info.max_sample_rate)
> +		return -EINVAL;
> +
> +	at91_adc_setup_samp_freq(st, val);
> +
> +	return 0;
> +}
> +
> +static const struct iio_info at91_adc_info = {
> +	.read_raw = &at91_adc_read_raw,
> +	.write_raw = &at91_adc_write_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +static int at91_adc_probe(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev;
> +	struct at91_adc_state *st;
> +	struct resource	*res;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&pdev->dev,
> +					  sizeof(struct at91_adc_state));
Utter nitpick that isn't going to hold up the patch...
I'd have done this as sizeof(*st)) but really doesn't matter.
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	indio_dev->dev.parent = &pdev->dev;
> +	indio_dev->name = dev_name(&pdev->dev);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->info = &at91_adc_info;
> +	indio_dev->channels = at91_adc_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(at91_adc_channels);
> +
> +	st = iio_priv(indio_dev);
> +
> +	ret = of_property_read_u32(pdev->dev.of_node,
> +				   "atmel,min-sample-rate-hz",
> +				   &st->soc_info.min_sample_rate);
> +	if (ret) {
> +		dev_err(&pdev->dev,
> +			"invalid or missing value for atmel,min-sample-rate-hz\n");
> +		return ret;
> +	}
> +
> +	ret = of_property_read_u32(pdev->dev.of_node,
> +				   "atmel,max-sample-rate-hz",
> +				   &st->soc_info.max_sample_rate);
> +	if (ret) {
> +		dev_err(&pdev->dev,
> +			"invalid or missing value for atmel,max-sample-rate-hz\n");
> +		return ret;
> +	}
> +
> +	ret = of_property_read_u32(pdev->dev.of_node, "atmel,startup-time-ms",
> +				   &st->soc_info.startup_time);
> +	if (ret) {
> +		dev_err(&pdev->dev,
> +			"invalid or missing value for atmel,startup-time-ms\n");
> +		return ret;
> +	}
> +
> +	init_waitqueue_head(&st->wq_data_available);
> +	mutex_init(&st->lock);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res)
> +		return -EINVAL;
> +
> +	st->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(st->base))
> +		return PTR_ERR(st->base);
> +
> +	st->irq = platform_get_irq(pdev, 0);
> +	if (st->irq <= 0) {
> +		if (!st->irq)
> +			st->irq = -ENXIO;
> +
> +		return st->irq;
> +	}
> +
> +	st->per_clk = devm_clk_get(&pdev->dev, "adc_clk");
> +	if (IS_ERR(st->per_clk))
> +		return PTR_ERR(st->per_clk);
> +
> +	st->reg = devm_regulator_get(&pdev->dev, "vddana");
> +	if (IS_ERR(st->reg))
> +		return PTR_ERR(st->reg);
> +
> +	st->vref = devm_regulator_get(&pdev->dev, "vref");
> +	if (IS_ERR(st->vref))
> +		return PTR_ERR(st->vref);
> +
> +	ret = devm_request_irq(&pdev->dev, st->irq, at91_adc_interrupt, 0,
> +			       pdev->dev.driver->name, indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = regulator_enable(st->reg);
> +	if (ret)
> +		return ret;
> +
> +	ret = regulator_enable(st->vref);
> +	if (ret)
> +		goto reg_disable;
> +
> +	st->vref_uv = regulator_get_voltage(st->vref);
> +	if (st->vref_uv <= 0) {
> +		ret = -EINVAL;
> +		goto vref_disable;
> +	}
> +
> +	at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
> +	at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
> +
> +	at91_adc_setup_samp_freq(st, st->soc_info.min_sample_rate);
> +
> +	ret = clk_prepare_enable(st->per_clk);
> +	if (ret)
> +		goto vref_disable;
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret < 0)
> +		goto per_clk_disable_unprepare;
> +
> +	dev_info(&pdev->dev, "version: %x\n",
> +		 readl_relaxed(st->base + AT91_SAMA5D2_VERSION));
> +
> +	return 0;
> +
> +per_clk_disable_unprepare:
> +	clk_disable_unprepare(st->per_clk);
> +vref_disable:
> +	regulator_disable(st->vref);
> +reg_disable:
> +	regulator_disable(st->reg);
> +	return ret;
> +}
> +
> +static int at91_adc_remove(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +	struct at91_adc_state *st = iio_priv(indio_dev);
> +
> +	iio_device_unregister(indio_dev);
> +
> +	clk_disable_unprepare(st->per_clk);
> +
> +	regulator_disable(st->vref);
> +	regulator_disable(st->reg);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id at91_adc_dt_match[] = {
> +	{
> +		.compatible = "atmel,sama5d2-adc",
> +	}, {
> +		/* sentinel */
> +	}
> +};
> +MODULE_DEVICE_TABLE(of, at91_adc_dt_match);
> +
> +static struct platform_driver at91_adc_driver = {
> +	.probe = at91_adc_probe,
> +	.remove = at91_adc_remove,
> +	.driver = {
> +		.name = "at91-sama5d2_adc",
> +		.of_match_table = at91_adc_dt_match,
> +	},
> +};
> +module_platform_driver(at91_adc_driver)
> +
> +MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
> +MODULE_DESCRIPTION("Atmel AT91 SAMA5D2 ADC");
> +MODULE_LICENSE("GPL v2");
>