by Jonathan Cameron

[permalink] [raw]

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

On 23 December 2015 10:48:33 GMT+00:00, Ludovic Desroches <[email protected]> wrote:
>On Wed, Dec 23, 2015 at 11:27:00AM +0100, Ludovic Desroches wrote:
>> On Tue, Dec 22, 2015 at 06:34:00PM +0000, Jonathan Cameron wrote:
>> > On 21/12/15 09:24, Ludovic Desroches wrote:
>> > > This driver supports the new version of the Atmel ADC device
>introduced
>> > > with the SAMA5D2 SoC family.
>> > >
>
>[...]
>
>> > > +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, ADC_ISR);
>> > > +
>> > > + status &= at91_adc_readl(st, ADC_IMR);
>> > > + if (status & 0xFFF) {
>> > > + st->last_value = at91_adc_readl(st, st->chan->address);
>> > If this is a polled read - is there any reason to read this value
>here
>> > rather than outside the interrupt?
>>
>> No it can be done outside the interrupt. I have taken some parts from
>the
>> previous driver but it was reading a register used by all the
>channels
>> when it has been designed. So yes there is probably no more reason to
>> read it into the interrupt.
>>
>
>Thinking about it. Is it really useful to move reading outside the
>interrupt?
It avoids needing to know the channel in here, hence simplifying the code a bit.
>
>By the way this is not a polled read.
I meant that it is an individually requested conversion rather than a free running
sampling system where the value read might change before it is read out.
>
>> > > + st->done = true;
>> > > + wake_up_interruptible(&st->wq_data_available);
>> > > + }
>> > > +
>> > > + return IRQ_HANDLED;
>> > > +}
>
>Ludovic
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--
Sent from my Android device with K-9 Mail. Please excuse my brevity.

2015-12-31 19:24:18

by Jonathan Cameron

[permalink] [raw]

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

On 23/12/15 10:27, Ludovic Desroches wrote:
> On Tue, Dec 22, 2015 at 06:34:00PM +0000, Jonathan Cameron wrote:
>> On 21/12/15 09:24, 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 <[email protected]>
>> A few more bits and bobs from me. Mostly looking good.
>>
>> Jonathan
>>> ---
>>> .../devicetree/bindings/iio/adc/at91_adc8xx.txt | 27 ++
>>> drivers/iio/adc/Kconfig | 11 +
>>> drivers/iio/adc/Makefile | 1 +
>>> drivers/iio/adc/at91_adc8xx.c | 417 +++++++++++++++++++++
>>> 4 files changed, 456 insertions(+)
>>> create mode 100644 Documentation/devicetree/bindings/iio/adc/at91_adc8xx.txt
>>> create mode 100644 drivers/iio/adc/at91_adc8xx.c
>>>
>>> diff --git a/Documentation/devicetree/bindings/iio/adc/at91_adc8xx.txt b/Documentation/devicetree/bindings/iio/adc/at91_adc8xx.txt
>>> new file mode 100644
>>> index 0000000..64ad6a5
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/iio/adc/at91_adc8xx.txt
>>> @@ -0,0 +1,27 @@
>>> +* 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: phandles to clocks.
>>> + - clock-names: tuple listing clock names.
>>> + Required elements: "adc_clk", "adc_op_clk". "adc_clk" is the peripheral
>>> + clock, "adc_clk" is the sampling clock.
>>> + - vref-supply: Supply used as reference for conversions.
>>> +
>>> +Optional properties:
>>> + - vddana-supply: Supply for the adc device.
>>> +
>>> +
>>> +Example:
>>> +
>>> +adc: adc@fc030000 {
>>> + compatible = "atmel,sama5d2-adc";
>>> + reg = <0xfc030000 0x100>;
>>> + interrupts = <40 IRQ_TYPE_LEVEL_HIGH 7>;
>>> + clocks = <&adc_clk>, <&adc_op_clk>;
>>> + clock-names = "adc_clk", "adc_op_clk";
>>> + 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 9162dfe..5819e41 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_ADC8xx
>>> + tristate "Atmel AT91 ADC 8xx"
>>> + depends on ARCH_AT91
>>> + depends on INPUT
>>> + help
>>> + Say yes here to build support for Atmel ADC 8xx which is available
>>> + from SAMA5D2 SoC family.
>>> +
>>> + To compile this driver as a module, choose M here: the module will be
>>> + called at91_adc8xx.
>>> +
>>> 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 91a65bf..d684a52 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-$(CONFIG_AT91_ADC8xx) += at91_adc8xx.o
>>> obj-$(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_adc8xx.c b/drivers/iio/adc/at91_adc8xx.c
>>> new file mode 100644
>>> index 0000000..8b4a6e7
>>> --- /dev/null
>>> +++ b/drivers/iio/adc/at91_adc8xx.c
>>> @@ -0,0 +1,417 @@
>>> +/*
>>> + * Atmel ADC driver for SAMA5D2 devices and later.
>>> + *
>>> + * Copyright (C) 2015 Atmel,
>>> + * 2015 Ludovic Desroches <[email protected]>
>>> + *
>>> + * 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/regulator/consumer.h>
>>> +
>>> +#define ADC_CR 0x00 /* Control Register */
>>> +#define ADC_CR_SWRST BIT(0) /* Software Reset */
>>> +#define ADC_CR_START BIT(1) /* Start Conversion */
>>> +#define ADC_CR_TSCALIB BIT(2) /* Touchscreen Calibration */
>>> +#define ADC_CR_CMPRST BIT(4) /* Comparison Restart */
>>> +#define ADC_MR 0x04 /* Mode Register */
>>> +#define ADC_MR_TRGSEL(v) (v << 1) /* Trigger Selection */
>>> +#define ADC_MR_TRGSEL_TRIG0 0 /* ADTRG */
>>> +#define ADC_MR_TRGSEL_TRIG1 1 /* TIOA0 */
>>> +#define ADC_MR_TRGSEL_TRIG2 2 /* TIOA1 */
>>> +#define ADC_MR_TRGSEL_TRIG3 3 /* TIOA2 */
>>> +#define ADC_MR_TRGSEL_TRIG4 4 /* PWM event line 0 */
>>> +#define ADC_MR_TRGSEL_TRIG5 5 /* PWM event line 1 */
>>> +#define ADC_MR_TRGSEL_TRIG6 6 /* TIOA3 */
>>> +#define ADC_MR_TRGSEL_TRIG7 7 /* RTCOUT0 */
>>> +#define ADC_MR_SLEEP BIT(5) /* Sleep Mode */
>>> +#define ADC_MR_FWUP BIT(6) /* Fast Wake Up */
>>> +#define ADC_MR_PRESCAL(v) (v << 8) /* Prescaler Rate Selection */
>>> +#define ADC_MR_PRESCAL_MAX 0xffff
>>> +#define ADC_MR_STARTUP(v) (v << 16) /* Startup Time */
>>> +#define ADC_MR_STARTUP_SUT0 0 /* 0 period of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT8 1 /* 8 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT16 2 /* 16 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT24 3 /* 24 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT64 4 /* 64 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT80 5 /* 80 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT96 6 /* 96 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT112 7 /* 112 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT512 8 /* 512 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT576 9 /* 576 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT640 10 /* 640 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT704 11 /* 704 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT768 12 /* 768 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT832 13 /* 832 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT896 14 /* 896 periods of ADCCLK */
>>> +#define ADC_MR_STARTUP_SUT960 15 /* 960 periods of ADCCLK */
>>> +#define ADC_MR_ANACH BIT(23) /* Analog Change */
>>> +#define ADC_MR_TRACKTIM(v) (v << 24) /* Tracking Time */
>>> +#define ADC_MR_TRACKTIM_MAX 0xff
>>> +#define ADC_MR_TRANSFER(v) (v << 28) /* Transfer Time */
>>> +#define ADC_MR_TRANSFER_MAX 0x3
>>> +#define ADC_MR_USEQ BIT(31) /* Use Sequence Enable */
>>> +#define ADC_SEQR1 0x08 /* Channel Sequence Register 1 */
>>> +#define ADC_SEQR2 0x0c /* Channel Sequence Register 2 */
>>> +#define ADC_CHER 0x10 /* Channel Enable Register */
>>> +#define ADC_CHDR 0x14 /* Channel Disable Register */
>>> +#define ADC_CHSR 0x18 /* Channel Status Register */
>>> +#define ADC_LCDR 0x20 /* Last Converted Data Register */
>>> +#define ADC_IER 0x24 /* Interrupt Enable Register */
>>> +#define ADC_IDR 0x28 /* Interrupt Disable Register */
>>> +#define ADC_IMR 0x2c /* Interrupt Mask Register */
>>> +#define ADC_ISR 0x30 /* Interrupt Status Register */
>>> +#define ADC_LCTMR 0x34 /* Last Channel Trigger Mode Register */
>>> +#define ADC_LCCWR 0x38 /* Last Channel Compare Window Register */
>>> +#define ADC_OVER 0x3c /* Overrun Status Register */
>>> +#define ADC_EMR 0x40 /* Extended Mode Register */
>>> +#define ADC_CWR 0x44 /* Compare Window Register */
>>> +#define ADC_CGR 0x48 /* Channel Gain Register */
>>> +#define ADC_COR 0x4c /* Channel Offset Register */
>>> +#define ADC_CDR0 0x50 /* Channel Data Register 0 */
>>> +#define ADC_ACR 0x94 /* Analog Control Register */
>>> +#define ADC_TSMR 0xb0 /* Touchscreen Mode Register */
>>> +#define ADC_XPOSR 0xb4 /* Touchscreen X Position Register */
>>> +#define ADC_YPOSR 0xb8 /* Touchscreen Y Position Register */
>>> +#define ADC_PRESSR 0xbc /* Touchscreen Pressure Register */
>>> +#define ADC_TRGR 0xc0 /* Trigger Register */
>>> +#define ADC_COSR 0xd0 /* Correction Select Register */
>>> +#define ADC_CVR 0xd4 /* Correction Value Register */
>>> +#define ADC_CECR 0xd8 /* Channel Error Correction Register */
>>> +#define ADC_WPMR 0xe4 /* Write Protection Mode Register */
>>> +#define ADC_WPSR 0xe8 /* Write Protection Status Register */
>>> +#define ADC_VERSION 0xfc /* Version Register */
>>> +
>>> +#define AT91_ADC_CHAN(num, addr) \
>>> + { \
>>> + .type = IIO_VOLTAGE, \
>>> + .channel = num, \
>>> + .address = addr, \
>>> + .scan_type = { \
>>> + .sign = 'u', \
>>> + .realbits = 12, \
>>> + .storagebits = 14, \
>>> + }, \
>>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
>>> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
>>> + .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_f_adc;
>>> + unsigned max_f_adc;
>>> + const struct iio_chan_spec *channels;
>>> + int num_channels;
>>> +};
>>> +
>>> +struct at91_adc_state {
>>> + void __iomem *base;
>>> + struct clk *per_clk;
>>> + struct clk *adc_clk;
>>> + int irq;
>>> + struct regulator *reg;
>>> + struct regulator *vref;
>>> + u32 vref_uv;
>>> + struct at91_adc_soc_info *soc_info;
>>> + wait_queue_head_t wq_data_available;
>>> + bool done;
>>> + const struct iio_chan_spec *chan;
>>> + u32 last_value;
>>> + struct mutex lock;
>>> +};
>>> +
>>> +static struct at91_adc_soc_info at91_adc_sama5d2_soc_info = {
>>> + .startup_time = 4,
>>> + .min_f_adc = 200000,
>>> + .max_f_adc = 20000000,
>> These rather look like things that should be in the device tree if they
>> are going to change between SoC varients.
>
> I have no strong position about it, I use to put parameters relative
> to a SoC family into the driver. They will change only for next SoC
> family not varients. When moving to a new family, the adc device could
> be a new one.
If we have to add these parameters to the devicetree later (to support a new
soc) that will be fine as long as the defaults are these (so it will work
with the older part).
>
> My only concern is to not put as many parameters in the device tree as
> at91_adc does.
A reasonable aim!
>
>>> +};
>>> +
>>> +static const struct iio_chan_spec at91_adc_channels[] = {
>>> + AT91_ADC_CHAN(0, 0x50),
>>> + AT91_ADC_CHAN(1, 0x54),
>>> + AT91_ADC_CHAN(2, 0x58),
>>> + AT91_ADC_CHAN(3, 0x5c),
>>> + AT91_ADC_CHAN(4, 0x60),
>>> + AT91_ADC_CHAN(5, 0x64),
>>> + AT91_ADC_CHAN(6, 0x68),
>>> + AT91_ADC_CHAN(7, 0x6c),
>>> + AT91_ADC_CHAN(8, 0x70),
>>> + AT91_ADC_CHAN(9, 0x74),
>>> + AT91_ADC_CHAN(10, 0x78),
>>> + AT91_ADC_CHAN(11, 0x7c),
>>> +};
>>> +
>>> +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, ADC_ISR);
>>> +
>>> + status &= at91_adc_readl(st, ADC_IMR);
>>> + if (status & 0xFFF) {
>>> + st->last_value = at91_adc_readl(st, st->chan->address);
>> If this is a polled read - is there any reason to read this value here
>> rather than outside the interrupt?
>
> No it can be done outside the interrupt. I have taken some parts from the
> previous driver but it was reading a register used by all the channels
> when it has been designed. So yes there is probably no more reason to
> read it into the interrupt.
>
>>> + st->done = true;
>>> + wake_up_interruptible(&st->wq_data_available);
>>> + }
>>> +
>>> + return IRQ_HANDLED;
>>> +}
>>> +
>>> +static bool at91_adc_freq_supported(struct at91_adc_state *st, unsigned freq)
>>> +{
>>> + return ((freq >= st->soc_info->min_f_adc)
>>> + && (freq <= st->soc_info->max_f_adc));
>>> +}
>>> +
>>> +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 int at91_adc_init(struct at91_adc_state *st)
>>> +{
>>> + struct iio_dev *indio_dev = iio_priv_to_dev(st);
>>> + unsigned f_adc, f_per, prescal, startup;
>>> +
>>> + at91_adc_writel(st, ADC_CR, ADC_CR_SWRST);
>>> + at91_adc_writel(st, ADC_IDR, 0xffffffff);
>>> +
>>> + f_adc = clk_get_rate(st->adc_clk);
>>> + if (!at91_adc_freq_supported(st, f_adc)) {
>>> + dev_err(&indio_dev->dev, "unsupported adc clock frequency\n");
>>> + return -EINVAL;
>>> + }
>>> +
>>> + f_per = clk_get_rate(st->per_clk);
>>> + prescal = (f_per / (2 * f_adc)) - 1;
>>> +
>>> + startup = at91_adc_startup_time(st->soc_info->startup_time,
>>> + f_adc / 1000);
>>> +
>>> + at91_adc_writel(st, ADC_MR,
>>> + ADC_MR_TRANSFER(2)
>>> + | ADC_MR_STARTUP(startup)
>>> + | ADC_MR_PRESCAL(prescal));
>>> +
>>> + dev_dbg(&indio_dev->dev, "startup: %u, prescal: %u\n",
>>> + startup, prescal);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +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;
>>> +
>>> + st->chan = chan;
>>> +
>>> + switch (mask) {
>>> + case IIO_CHAN_INFO_RAW:
>>> + mutex_lock(&st->lock);
>>> +
>>> + at91_adc_writel(st, ADC_CHER, BIT(chan->channel));
>>> + at91_adc_writel(st, ADC_IER, BIT(chan->channel));
>>> + at91_adc_writel(st, ADC_CR, ADC_CR_START);
>>> +
>>> + ret = wait_event_interruptible_timeout(st->wq_data_available,
>>> + st->done,
>>> + msecs_to_jiffies(1000));
>>> + if (ret == 0)
>>> + ret = -ETIMEDOUT;
>>> +
>>> + if (ret <= 0) {
>>> + at91_adc_writel(st, ADC_CHDR, BIT(chan->channel));
>>> + at91_adc_writel(st, ADC_IDR, BIT(chan->channel));
>>> + mutex_unlock(&st->lock);
>>> + return ret;
>>> + }
>>> +
>>> + if (chan->scan_type.sign == 's')
>>> + *val = sign_extend32(st->last_value,
>>> + chan->scan_type.realbits - 1);
>>> + else
>>> + *val = st->last_value;
>>> + at91_adc_writel(st, ADC_CHDR, BIT(chan->channel));
>>> + at91_adc_writel(st, ADC_IDR, BIT(chan->channel));
>>> + st->done = false;
>>> +
>>> + mutex_unlock(&st->lock);
>>> + return IIO_VAL_INT;
>>> +
>>> + case IIO_CHAN_INFO_SCALE:
>>> + *val = st->vref_uv / 1000;
>>> + *val2 = chan->scan_type.realbits;
>>> + return IIO_VAL_FRACTIONAL_LOG2;
>>> +
>>> + default:
>>> + return -EINVAL;
>>> + }
>>> +}
>>> +
>>> +static const struct iio_info at91_adc_info = {
>>> + .read_raw = &at91_adc_read_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));
>>> + 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);
>>> + st->soc_info = (struct at91_adc_soc_info *)
>>> + of_device_get_match_data(&pdev->dev);
>>> + 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)
>> could be be 0 (effectively marked as not present) - probably want to check
>> for that and fault out if so.
>
> ok.
>
>>> + 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->adc_clk = devm_clk_get(&pdev->dev, "adc_op_clk");
>>> + if (IS_ERR(st->adc_clk))
>>> + return PTR_ERR(st->adc_clk);
>>> +
>>> + st->reg = devm_regulator_get(&pdev->dev, "vddana");
>>> + if (IS_ERR(st->reg))
>>> + return PTR_ERR(st->reg);
>> You get this regulator but never explicitly request that it is on...
>> I can understand that for a reference like below (though probably want
>> to turn that on as well really).
>
> Yes, my regulators are always enabled, that's why I didn't think about
> turning them on.
>
>>> +
>>> + 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;
>>> +
>>> + st->vref_uv = regulator_get_voltage(st->vref);
>>> + if (st->vref_uv <= 0) {
>>> + ret = -EINVAL;
>>> + goto error;
>>> + }
>>> +
>>> + ret = at91_adc_init(st);
>>> + if (ret)
>>> + goto error;
>>> +
>>> + ret = clk_prepare_enable(st->adc_clk);
>> Handle these possible errors.
>>> + ret = clk_prepare_enable(st->per_clk);
>>> +
>>> + ret = iio_device_register(indio_dev);
>>> + if (ret < 0)
>>> + return ret;
>>> +
>>> + dev_info(&pdev->dev, "version: %x\n",
>>> + readl_relaxed(st->base + ADC_VERSION));
>>> +
>>> +error:
>>> + 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);
>>> + clk_disable_unprepare(st->adc_clk);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static const struct of_device_id at91_adc_dt_match[] = {
>>> + {
>>> + .compatible = "atmel,sama5d2-adc",
>>> + .data = &at91_adc_sama5d2_soc_info
>>> + }, {
>>> + /* 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_adc8xx",
>>> + .of_match_table = at91_adc_dt_match,
>>> + },
>>> +};
>>> +module_platform_driver(at91_adc_driver)
>>> +
>>> +MODULE_AUTHOR("Ludovic Desroches <[email protected]>");
>>> +MODULE_DESCRIPTION("Atmel AT91 ADC 8xx");
>>> +MODULE_LICENSE("GPL v2");
>>>
>>
>
> Thanks.
>
> Ludovic
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