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

From: Jonathan Cameron
Date: Sat Jan 16 2016 - 06:36:17 EST

On 16/01/16 11:27, Jonathan Cameron wrote:
> 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@xxxxxxxxx>
>> Acked-by: Rob Herring <robh@xxxxxxxxxx>
> 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.
Having said that - just noticed an oddity - why the DEPENDS on INPUT?
I'll drop that as a probable cut and paste issue as right now it doesn't
depend on INPUT (might at some later date of course!) Whilst there - to
improve general build coverage I've added COMPILE_TEST as an alternative
to at91 (works fine on my x86_64 compiler for starters)

Doing the COMPILE_TEST option tends to highlight any 'interesting' dependencies
that happen to get pulled in by other at91 dependencies at the moment and
reduces the chance of an IIO / kernel wide change breaking the driver.

Jonathan
>
> 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@xxxxxxxxx>
>> + *
>> + * 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@xxxxxxxxx>");
>> +MODULE_DESCRIPTION("Atmel AT91 SAMA5D2 ADC");
>> +MODULE_LICENSE("GPL v2");
>>
>