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SubjectRe: [PATCH 2/3] iio: adc: mxs-lradc: Add support for adc driver
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On Sun, May 1, 2016 at 6:38 PM, Jonathan Cameron <jic23@kernel.org> wrote:
> On 29/04/16 12:48, Ksenija Stanojevic wrote:
>> Add mxs-lradc adc driver.
>>
>> Signed-off-by: Ksenija Stanojevic <ksenija.stanojevic@gmail.com>
> Mostly looking good. A few nitpicks and suggestions inline.
>
> Jonathan
>> ---
>> drivers/iio/adc/Kconfig | 37 +-
>> drivers/iio/adc/Makefile | 1 +
>> drivers/iio/adc/mxs-lradc-adc.c | 832 ++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 858 insertions(+), 12 deletions(-)
>> create mode 100644 drivers/iio/adc/mxs-lradc-adc.c
>>
>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>> index 82c718c..50847b8 100644
>> --- a/drivers/iio/adc/Kconfig
>> +++ b/drivers/iio/adc/Kconfig
>> @@ -233,6 +233,19 @@ config IMX7D_ADC
>> This driver can also be built as a module. If so, the module will be
>> called imx7d_adc.
>>
>> +config MXS_LRADC_ADC
>> + tristate "Freescale i.MX23/i.MX28 LRADC ADC"
>> + depends on MFD_MXS_LRADC
>> + select IIO_BUFFER
>> + select IIO_TRIGGERED_BUFFER
>> + help
>> + Say yes here to build support for the ADC functions of the
>> + i.MX23/i.MX28 LRADC. This includes general-purpose ADC readings,
>> + battery voltage measurement, and die temperature measurement.
>> +
>> + This driver can also be built as a module. If so, the module will be
>> + called mxs-lradc-adc.
>> +
>> config LP8788_ADC
>> tristate "LP8788 ADC driver"
>> depends on MFD_LP8788
>> @@ -306,18 +319,18 @@ config MEN_Z188_ADC
>> called men_z188_adc.
>>
>> config MXS_LRADC
>> - tristate "Freescale i.MX23/i.MX28 LRADC"
>> - depends on (ARCH_MXS || COMPILE_TEST) && HAS_IOMEM
>> - depends on INPUT
>> - select STMP_DEVICE
>> - select IIO_BUFFER
>> - select IIO_TRIGGERED_BUFFER
>> - help
>> - Say yes here to build support for i.MX23/i.MX28 LRADC convertor
>> - built into these chips.
>> -
>> - To compile this driver as a module, choose M here: the
>> - module will be called mxs-lradc.
>> + tristate "Freescale i.MX23/i.MX28 LRADC"
>> + depends on (ARCH_MXS || COMPILE_TEST) && HAS_IOMEM
>> + depends on INPUT
>> + select STMP_DEVICE
>> + select IIO_BUFFER
>> + select IIO_TRIGGERED_BUFFER
>> + help
>> + Say yes here to build support for i.MX23/i.MX28 LRADC convertor
>> + built into these chips.
>> +
>> + To compile this driver as a module, choose M here: the
>> + module will be called mxs-lradc.
>>
>> config NAU7802
>> tristate "Nuvoton NAU7802 ADC driver"
>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
>> index 0cb7921..ca7d6aa 100644
>> --- a/drivers/iio/adc/Makefile
>> +++ b/drivers/iio/adc/Makefile
>> @@ -31,6 +31,7 @@ obj-$(CONFIG_MCP320X) += mcp320x.o
>> obj-$(CONFIG_MCP3422) += mcp3422.o
>> obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
>> obj-$(CONFIG_MXS_LRADC) += mxs-lradc.o
>> +obj-$(CONFIG_MXS_LRADC_ADC) += mxs-lradc-adc.o
>> obj-$(CONFIG_NAU7802) += nau7802.o
>> obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
>> obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
>> diff --git a/drivers/iio/adc/mxs-lradc-adc.c b/drivers/iio/adc/mxs-lradc-adc.c
>> new file mode 100644
>> index 0000000..793c369
>> --- /dev/null
>> +++ b/drivers/iio/adc/mxs-lradc-adc.c
>> @@ -0,0 +1,832 @@
>> +/*
>> + * Freescale MXS LRADC ADC driver
>> + *
>> + * Copyright (c) 2012 DENX Software Engineering, GmbH.
>> + * Marek Vasut <marex@denx.de>
> You should probably add your own copyright as you are making substantial
> improvements!
>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * 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/mfd/mxs-lradc.h>
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +
>> +#include <linux/iio/buffer.h>
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/trigger.h>
>> +#include <linux/iio/trigger_consumer.h>
>> +#include <linux/iio/triggered_buffer.h>
>> +#include <linux/iio/sysfs.h>
>> +
>> +/*
>> + * Make this runtime configurable if necessary. Currently, if the buffered mode
>> + * is enabled, the LRADC takes LRADC_DELAY_TIMER_LOOP samples of data before
>> + * triggering IRQ. The sampling happens every (LRADC_DELAY_TIMER_PER / 2000)
>> + * seconds. The result is that the samples arrive every 500mS.
>> + */
>> +#define LRADC_DELAY_TIMER_PER 200
>> +#define LRADC_DELAY_TIMER_LOOP 5
>> +
>> +#define VREF_MV_BASE 1850
>> +
>> +static const u32 mxs_lradc_adc_vref_mv[][LRADC_MAX_TOTAL_CHANS] = {
>> + [IMX23_LRADC] = {
>> + VREF_MV_BASE, /* CH0 */
>> + VREF_MV_BASE, /* CH1 */
>> + VREF_MV_BASE, /* CH2 */
>> + VREF_MV_BASE, /* CH3 */
>> + VREF_MV_BASE, /* CH4 */
>> + VREF_MV_BASE, /* CH5 */
>> + VREF_MV_BASE * 2, /* CH6 VDDIO */
>> + VREF_MV_BASE * 4, /* CH7 VBATT */
>> + VREF_MV_BASE, /* CH8 Temp sense 0 */
>> + VREF_MV_BASE, /* CH9 Temp sense 1 */
>> + VREF_MV_BASE, /* CH10 */
>> + VREF_MV_BASE, /* CH11 */
>> + VREF_MV_BASE, /* CH12 USB_DP */
>> + VREF_MV_BASE, /* CH13 USB_DN */
>> + VREF_MV_BASE, /* CH14 VBG */
>> + VREF_MV_BASE * 4, /* CH15 VDD5V */
>> + },
>> + [IMX28_LRADC] = {
>> + VREF_MV_BASE, /* CH0 */
>> + VREF_MV_BASE, /* CH1 */
>> + VREF_MV_BASE, /* CH2 */
>> + VREF_MV_BASE, /* CH3 */
>> + VREF_MV_BASE, /* CH4 */
>> + VREF_MV_BASE, /* CH5 */
>> + VREF_MV_BASE, /* CH6 */
>> + VREF_MV_BASE * 4, /* CH7 VBATT */
>> + VREF_MV_BASE, /* CH8 Temp sense 0 */
>> + VREF_MV_BASE, /* CH9 Temp sense 1 */
>> + VREF_MV_BASE * 2, /* CH10 VDDIO */
>> + VREF_MV_BASE, /* CH11 VTH */
>> + VREF_MV_BASE * 2, /* CH12 VDDA */
>> + VREF_MV_BASE, /* CH13 VDDD */
>> + VREF_MV_BASE, /* CH14 VBG */
>> + VREF_MV_BASE * 4, /* CH15 VDD5V */
>> + },
>> +};
>> +
>> +enum mxs_lradc_divbytwo {
>> + MXS_LRADC_DIV_DISABLED = 0,
>> + MXS_LRADC_DIV_ENABLED,
>> +};
>> +
>> +struct mxs_lradc_scale {
>> + unsigned int integer;
>> + unsigned int nano;
>> +};
>> +
>> +struct mxs_lradc_adc {
>> + struct mxs_lradc *lradc;
>> + struct device *dev;
>> +
>> + u32 *buffer;
>> + struct iio_trigger *trig;
>> + struct mutex lock;
>> + struct completion completion;
>> +
>> + const u32 *vref_mv;
>> + struct mxs_lradc_scale scale_avail[LRADC_MAX_TOTAL_CHANS][2];
>> + unsigned long is_divided;
>> +};
>> +
>> +/*
>> + * Raw I/O operations
>> + */
>> +static int mxs_lradc_adc_read_single(struct iio_dev *iio_dev, int chan,
>> + int *val)
>> +{
>> + struct mxs_lradc_adc *adc = iio_priv(iio_dev);
>> + struct mxs_lradc *lradc = adc->lradc;
>> + int ret;
>> +
>> + /*
>> + * See if there is no buffered operation in progress. If there is simply
>> + * bail out. This can be improved to support both buffered and raw IO at
>> + * the same time, yet the code becomes horribly complicated. Therefore I
>> + * applied KISS principle here.
> This is true in lots of devices! Hence we often have a similar check.
>> + */
>> + ret = mutex_trylock(&adc->lock);
>> + if (!ret)
>> + return -EBUSY;
> We have standard core infrastructure for this now that should do the trick.
> iio_device_claim_direct_mode() etc.
>> +
>> + reinit_completion(&adc->completion);
>> +
>> + /*
>> + * No buffered operation in progress, map the channel and trigger it.
>> + * Virtual channel 0 is always used here as the others are always not
>> + * used if doing raw sampling.
>> + */
>> + if (lradc->soc == IMX28_LRADC)
>> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(0),
>> + LRADC_CTRL1);
>> + mxs_lradc_reg_clear(lradc, 0x1, LRADC_CTRL0);
>> +
>> + /* Enable / disable the divider per requirement */
>> + if (test_bit(chan, &adc->is_divided))
>> + mxs_lradc_reg_set(lradc,
>> + 1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
>> + LRADC_CTRL2);
>> + else
>> + mxs_lradc_reg_clear(lradc,
>> + 1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
>> + LRADC_CTRL2);
>> +
>> + /* Clean the slot's previous content, then set new one. */
>> + mxs_lradc_reg_clear(lradc, LRADC_CTRL4_LRADCSELECT_MASK(0),
>> + LRADC_CTRL4);
>> + mxs_lradc_reg_set(lradc, chan, LRADC_CTRL4);
>> +
>> + mxs_lradc_reg_wrt(lradc, 0, LRADC_CH(0));
>> +
>> + /* Enable the IRQ and start sampling the channel. */
>> + mxs_lradc_reg_set(lradc, LRADC_CTRL1_LRADC_IRQ_EN(0), LRADC_CTRL1);
>> + mxs_lradc_reg_set(lradc, BIT(0), LRADC_CTRL0);
>> +
>> + /* Wait for completion on the channel, 1 second max. */
>> + ret = wait_for_completion_killable_timeout(&adc->completion, HZ);
>> + if (!ret)
>> + ret = -ETIMEDOUT;
>> + if (ret < 0)
>> + goto err;
>> +
>> + /* Read the data. */
>> + *val = readl(lradc->base + LRADC_CH(0)) & LRADC_CH_VALUE_MASK;
>> + ret = IIO_VAL_INT;
>> +
>> +err:
>> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(0), LRADC_CTRL1);
>> +
>> + mutex_unlock(&adc->lock);
>> +
>> + return ret;
>> +}
>> +
>> +static int mxs_lradc_adc_read_temp(struct iio_dev *iio_dev, int *val)
>> +{
>> + int ret, min, max;
>> +
>> + ret = mxs_lradc_adc_read_single(iio_dev, 8, &min);
>> + if (ret != IIO_VAL_INT)
>> + return ret;
>> +
>> + ret = mxs_lradc_adc_read_single(iio_dev, 9, &max);
>> + if (ret != IIO_VAL_INT)
>> + return ret;
>> +
>> + *val = max - min;
>> +
>> + return IIO_VAL_INT;
>> +}
>> +
>> +static int mxs_lradc_adc_read_raw(struct iio_dev *iio_dev,
>> + const struct iio_chan_spec *chan,
>> + int *val, int *val2, long m)
>> +{
>> + struct mxs_lradc_adc *adc = iio_priv(iio_dev);
>> +
>> + switch (m) {
>> + case IIO_CHAN_INFO_RAW:
>> + if (chan->type == IIO_TEMP)
>> + return mxs_lradc_adc_read_temp(iio_dev, val);
>> +
>> + return mxs_lradc_adc_read_single(iio_dev, chan->channel, val);
>> +
>> + case IIO_CHAN_INFO_SCALE:
>> + if (chan->type == IIO_TEMP) {
>> + /* From the datasheet, we have to multiply by 1.012 and
>> + * divide by 4
>> + */
>> + *val = 0;
>> + *val2 = 253000;
>> + return IIO_VAL_INT_PLUS_MICRO;
>> + }
>> +
>> + *val = adc->vref_mv[chan->channel];
>> + *val2 = chan->scan_type.realbits -
>> + test_bit(chan->channel, &adc->is_divided);
> blank line here as you have done elsewhere...
>> + return IIO_VAL_FRACTIONAL_LOG2;
>> +
>> + case IIO_CHAN_INFO_OFFSET:
>> + if (chan->type == IIO_TEMP) {
> standard multiline comment syntax please. Please fix this throughout.
>
> /*
> * The ...
>> + /* The calculated value from the ADC is in Kelvin, we
>> + * want Celsius for hwmon so the offset is -273.15
>> + * The offset is applied before scaling so it is
>> + * actually -213.15 * 4 / 1.012 = -1079.644268
>> + */
>> + *val = -1079;
>> + *val2 = 644268;
>> +
>> + return IIO_VAL_INT_PLUS_MICRO;
>> + }
>> +
>> + return -EINVAL;
>> +
>> + default:
>> + break;
>> + }
>> +
>> + return -EINVAL;
>> +}
>> +
>> +static int mxs_lradc_adc_write_raw(struct iio_dev *iio_dev,
>> + const struct iio_chan_spec *chan,
>> + int val, int val2, long m)
>> +{
>> + struct mxs_lradc_adc *adc = iio_priv(iio_dev);
>> + struct mxs_lradc_scale *scale_avail =
>> + adc->scale_avail[chan->channel];
>> + int ret;
>> +
>> + ret = mutex_trylock(&adc->lock);
>> + if (!ret)
>> + return -EBUSY;
>> +
>> + switch (m) {
>> + case IIO_CHAN_INFO_SCALE:
>> + ret = -EINVAL;
>> + if (val == scale_avail[MXS_LRADC_DIV_DISABLED].integer &&
>> + val2 == scale_avail[MXS_LRADC_DIV_DISABLED].nano) {
>> + /* divider by two disabled */
>> + clear_bit(chan->channel, &adc->is_divided);
>> + ret = 0;
>> + } else if (val == scale_avail[MXS_LRADC_DIV_ENABLED].integer &&
>> + val2 == scale_avail[MXS_LRADC_DIV_ENABLED].nano) {
>> + /* divider by two enabled */
>> + set_bit(chan->channel, &adc->is_divided);
>> + ret = 0;
>> + }
>> +
>> + break;
>> + default:
>> + ret = -EINVAL;
>> + break;
>> + }
>> +
>> + mutex_unlock(&adc->lock);
>> +
>> + return ret;
>> +}
>> +
>> +static int mxs_lradc_adc_write_raw_get_fmt(struct iio_dev *iio_dev,
>> + const struct iio_chan_spec *chan,
>> + long m)
>> +{
>> + return IIO_VAL_INT_PLUS_NANO;
>> +}
>> +
>> +static ssize_t mxs_lradc_adc_show_scale_avail_ch(struct device *dev,
>> + struct device_attribute *attr,
>> + char *buf,
>> + int ch)
>> +{
>> + struct iio_dev *iio = dev_to_iio_dev(dev);
>> + struct mxs_lradc_adc *adc = iio_priv(iio);
>> + int i, len = 0;
>> +
>> + for (i = 0; i < ARRAY_SIZE(adc->scale_avail[ch]); i++)
>> + len += sprintf(buf + len, "%u.%09u ",
>> + adc->scale_avail[ch][i].integer,
>> + adc->scale_avail[ch][i].nano);
>> +
>> + len += sprintf(buf + len, "\n");
>> +
>> + return len;
>> +}
>> +
> I'm unconvinced this wrapper adds anything...
>> +static ssize_t mxs_lradc_adc_show_scale_avail(struct device *dev,
>> + struct device_attribute *attr,
>> + char *buf)
>> +{
>> + struct iio_dev_attr *iio_attr = to_iio_dev_attr(attr);
>> +
>> + return mxs_lradc_adc_show_scale_avail_ch(dev, attr, buf,
>> + iio_attr->address);
>> +}
>> +
>> +#define SHOW_SCALE_AVAILABLE_ATTR(ch) \
>> +static IIO_DEVICE_ATTR(in_voltage##ch##_scale_available, S_IRUGO, \
>> + mxs_lradc_adc_show_scale_avail, NULL, ch)
>> +
>> +SHOW_SCALE_AVAILABLE_ATTR(0);
>> +SHOW_SCALE_AVAILABLE_ATTR(1);
>> +SHOW_SCALE_AVAILABLE_ATTR(2);
>> +SHOW_SCALE_AVAILABLE_ATTR(3);
>> +SHOW_SCALE_AVAILABLE_ATTR(4);
>> +SHOW_SCALE_AVAILABLE_ATTR(5);
>> +SHOW_SCALE_AVAILABLE_ATTR(6);
>> +SHOW_SCALE_AVAILABLE_ATTR(7);
>> +SHOW_SCALE_AVAILABLE_ATTR(10);
>> +SHOW_SCALE_AVAILABLE_ATTR(11);
>> +SHOW_SCALE_AVAILABLE_ATTR(12);
>> +SHOW_SCALE_AVAILABLE_ATTR(13);
>> +SHOW_SCALE_AVAILABLE_ATTR(14);
>> +SHOW_SCALE_AVAILABLE_ATTR(15);
>> +
>> +static struct attribute *mxs_lradc_adc_attributes[] = {
>> + &iio_dev_attr_in_voltage0_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage1_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage2_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage3_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage4_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage5_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage6_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage7_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage10_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage11_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage12_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage13_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage14_scale_available.dev_attr.attr,
>> + &iio_dev_attr_in_voltage15_scale_available.dev_attr.attr,
>> + NULL
>> +};
>> +
>> +static const struct attribute_group mxs_lradc_adc_attribute_group = {
>> + .attrs = mxs_lradc_adc_attributes,
>> +};
>> +
>> +static const struct iio_info mxs_lradc_adc_iio_info = {
>> + .driver_module = THIS_MODULE,
>> + .read_raw = mxs_lradc_adc_read_raw,
>> + .write_raw = mxs_lradc_adc_write_raw,
>> + .write_raw_get_fmt = mxs_lradc_adc_write_raw_get_fmt,
>> + .attrs = &mxs_lradc_adc_attribute_group,
>> +};
>> +
>> +/*
>> + * IRQ Handling
>> + */
> Single line comment syntax preferred.
>> +static irqreturn_t mxs_lradc_adc_handle_irq(int irq, void *data)
>> +{
>> + struct iio_dev *iio = data;
>> + struct mxs_lradc_adc *adc = iio_priv(iio);
>> + struct mxs_lradc *lradc = adc->lradc;
>> + unsigned long reg = readl(lradc->base + LRADC_CTRL1);
>> +
>> + if (!(reg & mxs_lradc_irq_mask(lradc)))
>> + return IRQ_NONE;
>> +
>> + if (iio_buffer_enabled(iio)) {
>> + if (reg & lradc->buffer_vchans)
>> + iio_trigger_poll(iio->trig);
>> + } else if (reg & LRADC_CTRL1_LRADC_IRQ(0)) {
>> + complete(&adc->completion);
>> + }
>> +
>> + mxs_lradc_reg_clear(lradc, reg & mxs_lradc_irq_mask(lradc),
>> + LRADC_CTRL1);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +/*
>> + * Trigger handling
> Single line comment - Clearly it's kind of more of a heading but I'd rather
> not deal with the inevitable patch converting it to the standard single line
> format!
>> + */
>> +static irqreturn_t mxs_lradc_adc_trigger_handler(int irq, void *p)
>> +{
>> + struct iio_poll_func *pf = p;
>> + struct iio_dev *iio = pf->indio_dev;
>> + struct mxs_lradc_adc *adc = iio_priv(iio);
>> + const u32 chan_value = LRADC_CH_ACCUMULATE |
>> + ((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
>> + unsigned int i, j = 0;
>> +
>> + for_each_set_bit(i, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
>> + adc->buffer[j] = readl(adc->lradc->base + LRADC_CH(j));
>> + mxs_lradc_reg_wrt(adc->lradc, chan_value, LRADC_CH(j));
>> + adc->buffer[j] &= LRADC_CH_VALUE_MASK;
>> + adc->buffer[j] /= LRADC_DELAY_TIMER_LOOP;
>> + j++;
>> + }
>> +
>> + iio_push_to_buffers_with_timestamp(iio, adc->buffer, pf->timestamp);
>> +
>> + iio_trigger_notify_done(iio->trig);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static int mxs_lradc_adc_configure_trigger(struct iio_trigger *trig, bool state)
>> +{
>> + struct iio_dev *iio = iio_trigger_get_drvdata(trig);
>> + struct mxs_lradc_adc *adc = iio_priv(iio);
>> + const u32 st = state ? STMP_OFFSET_REG_SET : STMP_OFFSET_REG_CLR;
>> +
>> + mxs_lradc_reg_wrt(adc->lradc, LRADC_DELAY_KICK, LRADC_DELAY(0) + st);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct iio_trigger_ops mxs_lradc_adc_trigger_ops = {
>> + .owner = THIS_MODULE,
>> + .set_trigger_state = &mxs_lradc_adc_configure_trigger,
>> +};
>> +
>> +static int mxs_lradc_adc_trigger_init(struct iio_dev *iio)
>> +{
>> + int ret;
>> + struct iio_trigger *trig;
>> + struct mxs_lradc_adc *adc = iio_priv(iio);
>> +
> Could simplify things ever so slightly by using devm_iio_trigger_alloc if you
> were to reorder the trigger init to be before the buffer setup (which I think
> should be fine). Perhaps it is not worth the hassle...
>> + trig = iio_trigger_alloc("%s-dev%i", iio->name, iio->id);
>> + if (!trig)
>> + return -ENOMEM;
>> +
>> + trig->dev.parent = adc->dev;
>> + iio_trigger_set_drvdata(trig, iio);
>> + trig->ops = &mxs_lradc_adc_trigger_ops;
>> +
>> + ret = iio_trigger_register(trig);
>> + if (ret) {
>> + iio_trigger_free(trig);
>> + return ret;
>> + }
>> +
>> + adc->trig = trig;
>> +
>> + return 0;
>> +}
>> +
>> +static void mxs_lradc_adc_trigger_remove(struct iio_dev *iio)
>> +{
>> + struct mxs_lradc_adc *adc = iio_priv(iio);
>> +
>> + iio_trigger_unregister(adc->trig);
>> + iio_trigger_free(adc->trig);
>> +}
>> +
>> +static int mxs_lradc_adc_buffer_preenable(struct iio_dev *iio)
>> +{
>> + struct mxs_lradc_adc *adc = iio_priv(iio);
>> + struct mxs_lradc *lradc = adc->lradc;
>> + int ret = 0, chan, ofs = 0;
>> + unsigned long enable = 0;
>> + u32 ctrl4_set = 0;
>> + u32 ctrl4_clr = 0;
>> + u32 ctrl1_irq = 0;
>> + const u32 chan_value = LRADC_CH_ACCUMULATE |
>> + ((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
>> + const int len = bitmap_weight(iio->active_scan_mask,
>> + LRADC_MAX_TOTAL_CHANS);
>> +
>> + if (!len)
>> + return -EINVAL;
>> +
>> + /*
>> + * Lock the driver so raw access can not be done during buffered
>> + * operation. This simplifies the code a lot.
>> + */
>> + ret = mutex_trylock(&adc->lock);
>> + if (!ret)
>> + return -EBUSY;
> Hmm. could this use iio_dev->mlock? That is what that particular lock is
> for and it has nice wrapper functions to make it clear.
>> +
>> + adc->buffer = kmalloc_array(len, sizeof(*adc->buffer), GFP_KERNEL);
>> + if (!adc->buffer) {
>> + ret = -ENOMEM;
>> + goto err_mem;
>> + }
> I wonder if it's worth the hassel of doing this dynamically. Maybe just have a
> buffer that is big enough to take all possibilities as part of the adc
> struct?
>> +
>> + if (lradc->soc == IMX28_LRADC)
>> + mxs_lradc_reg_clear(
>> + lradc,
>> + lradc->buffer_vchans << LRADC_CTRL1_LRADC_IRQ_EN_OFFSET,
>> + LRADC_CTRL1);
>> + mxs_lradc_reg_clear(lradc, lradc->buffer_vchans, LRADC_CTRL0);
>> +
>> + for_each_set_bit(chan, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
>> + ctrl4_set |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs);
>> + ctrl4_clr |= LRADC_CTRL4_LRADCSELECT_MASK(ofs);
>> + ctrl1_irq |= LRADC_CTRL1_LRADC_IRQ_EN(ofs);
>> + mxs_lradc_reg_wrt(lradc, chan_value, LRADC_CH(ofs));
>> + bitmap_set(&enable, ofs, 1);
>> + ofs++;
>> + }
>> +
>> + mxs_lradc_reg_clear(lradc, LRADC_DELAY_TRIGGER_LRADCS_MASK |
>> + LRADC_DELAY_KICK, LRADC_DELAY(0));
>> + mxs_lradc_reg_clear(lradc, ctrl4_clr, LRADC_CTRL4);
>> + mxs_lradc_reg_set(lradc, ctrl4_set, LRADC_CTRL4);
>> + mxs_lradc_reg_set(lradc, ctrl1_irq, LRADC_CTRL1);
>> + mxs_lradc_reg_set(lradc, enable << LRADC_DELAY_TRIGGER_LRADCS_OFFSET,
>> + LRADC_DELAY(0));
>> +
>> + return 0;
>> +
>> +err_mem:
>> + mutex_unlock(&adc->lock);
>> + return ret;
>> +}
>> +
>> +static int mxs_lradc_adc_buffer_postdisable(struct iio_dev *iio)
>> +{
>> + struct mxs_lradc_adc *adc = iio_priv(iio);
>> + struct mxs_lradc *lradc = adc->lradc;
>> +
>> + mxs_lradc_reg_clear(lradc, LRADC_DELAY_TRIGGER_LRADCS_MASK |
>> + LRADC_DELAY_KICK, LRADC_DELAY(0));
>> +
>> + mxs_lradc_reg_clear(lradc, lradc->buffer_vchans, LRADC_CTRL0);
>> + if (lradc->soc == IMX28_LRADC)
>> + mxs_lradc_reg_clear(
>> + lradc,
>> + lradc->buffer_vchans << LRADC_CTRL1_LRADC_IRQ_EN_OFFSET,
>> + LRADC_CTRL1);
>> +
>> + kfree(adc->buffer);
>> + mutex_unlock(&adc->lock);
>> +
>> + return 0;
>> +}
>> +
>> +static bool mxs_lradc_adc_validate_scan_mask(struct iio_dev *iio,
>> + const unsigned long *mask)
>> +{
>> + struct mxs_lradc_adc *adc = iio_priv(iio);
>> + struct mxs_lradc *lradc = adc->lradc;
>> + const int map_chans = bitmap_weight(mask, LRADC_MAX_TOTAL_CHANS);
>> + int rsvd_chans = 0;
>> + unsigned long rsvd_mask = 0;
>> +
>> + if (lradc->use_touchbutton)
>> + rsvd_mask |= CHAN_MASK_TOUCHBUTTON;
>> + if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_4WIRE)
>> + rsvd_mask |= CHAN_MASK_TOUCHSCREEN_4WIRE;
>> + if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE)
>> + rsvd_mask |= CHAN_MASK_TOUCHSCREEN_5WIRE;
>> +
>> + if (lradc->use_touchbutton)
>> + rsvd_chans++;
>> + if (lradc->use_touchscreen)
>> + rsvd_chans += 2;
>> +
>> + /* Test for attempts to map channels with special mode of operation. */
>> + if (bitmap_intersects(mask, &rsvd_mask, LRADC_MAX_TOTAL_CHANS))
>> + return false;
>> +
>> + /* Test for attempts to map more channels then available slots. */
>> + if (map_chans + rsvd_chans > LRADC_MAX_MAPPED_CHANS)
>> + return false;
>> +
>> + return true;
>> +}
>> +
>> +static const struct iio_buffer_setup_ops mxs_lradc_adc_buffer_ops = {
>> + .preenable = &mxs_lradc_adc_buffer_preenable,
>> + .postenable = &iio_triggered_buffer_postenable,
>> + .predisable = &iio_triggered_buffer_predisable,
>> + .postdisable = &mxs_lradc_adc_buffer_postdisable,
>> + .validate_scan_mask = &mxs_lradc_adc_validate_scan_mask,
>> +};
>> +
>> +/*
>> + * Driver initialization
>> + */
>> +
>> +#define MXS_ADC_CHAN(idx, chan_type, name) { \
>> + .type = (chan_type), \
>> + .indexed = 1, \
>> + .scan_index = (idx), \
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
>> + BIT(IIO_CHAN_INFO_SCALE), \
>> + .channel = (idx), \
>> + .address = (idx), \
>> + .scan_type = { \
>> + .sign = 'u', \
>> + .realbits = LRADC_RESOLUTION, \
>> + .storagebits = 32, \
>> + }, \
>> + .datasheet_name = (name), \
>> +}
>> +
>> +static const struct iio_chan_spec mx23_lradc_chan_spec[] = {
>> + MXS_ADC_CHAN(0, IIO_VOLTAGE, "LRADC0"),
>> + MXS_ADC_CHAN(1, IIO_VOLTAGE, "LRADC1"),
>> + MXS_ADC_CHAN(2, IIO_VOLTAGE, "LRADC2"),
>> + MXS_ADC_CHAN(3, IIO_VOLTAGE, "LRADC3"),
>> + MXS_ADC_CHAN(4, IIO_VOLTAGE, "LRADC4"),
>> + MXS_ADC_CHAN(5, IIO_VOLTAGE, "LRADC5"),
>> + MXS_ADC_CHAN(6, IIO_VOLTAGE, "VDDIO"),
>> + MXS_ADC_CHAN(7, IIO_VOLTAGE, "VBATT"),
>> + /* Combined Temperature sensors */
>> + {
>> + .type = IIO_TEMP,
>> + .indexed = 1,
>> + .scan_index = 8,
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>> + BIT(IIO_CHAN_INFO_OFFSET) |
>> + BIT(IIO_CHAN_INFO_SCALE),
>> + .channel = 8,
>> + .scan_type = {.sign = 'u', .realbits = 18, .storagebits = 32,},
>> + .datasheet_name = "TEMP_DIE",
>> + },
>> + /* Hidden channel to keep indexes */
>> + {
>> + .type = IIO_TEMP,
>> + .indexed = 1,
>> + .scan_index = -1,
>> + .channel = 9,
>> + },
>> + MXS_ADC_CHAN(10, IIO_VOLTAGE, NULL),
>> + MXS_ADC_CHAN(11, IIO_VOLTAGE, NULL),
>> + MXS_ADC_CHAN(12, IIO_VOLTAGE, "USB_DP"),
>> + MXS_ADC_CHAN(13, IIO_VOLTAGE, "USB_DN"),
>> + MXS_ADC_CHAN(14, IIO_VOLTAGE, "VBG"),
>> + MXS_ADC_CHAN(15, IIO_VOLTAGE, "VDD5V"),
>> +};
>> +
>> +static const struct iio_chan_spec mx28_lradc_chan_spec[] = {
>> + MXS_ADC_CHAN(0, IIO_VOLTAGE, "LRADC0"),
>> + MXS_ADC_CHAN(1, IIO_VOLTAGE, "LRADC1"),
>> + MXS_ADC_CHAN(2, IIO_VOLTAGE, "LRADC2"),
>> + MXS_ADC_CHAN(3, IIO_VOLTAGE, "LRADC3"),
>> + MXS_ADC_CHAN(4, IIO_VOLTAGE, "LRADC4"),
>> + MXS_ADC_CHAN(5, IIO_VOLTAGE, "LRADC5"),
>> + MXS_ADC_CHAN(6, IIO_VOLTAGE, "LRADC6"),
>> + MXS_ADC_CHAN(7, IIO_VOLTAGE, "VBATT"),
>> + /* Combined Temperature sensors */
>> + {
>> + .type = IIO_TEMP,
>> + .indexed = 1,
>> + .scan_index = 8,
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>> + BIT(IIO_CHAN_INFO_OFFSET) |
>> + BIT(IIO_CHAN_INFO_SCALE),
>> + .channel = 8,
>> + .scan_type = {.sign = 'u', .realbits = 18, .storagebits = 32,},
>> + .datasheet_name = "TEMP_DIE",
>> + },
>> + /* Hidden channel to keep indexes */
>> + {
>> + .type = IIO_TEMP,
>> + .indexed = 1,
>> + .scan_index = -1,
>> + .channel = 9,
>> + },
>> + MXS_ADC_CHAN(10, IIO_VOLTAGE, "VDDIO"),
>> + MXS_ADC_CHAN(11, IIO_VOLTAGE, "VTH"),
>> + MXS_ADC_CHAN(12, IIO_VOLTAGE, "VDDA"),
>> + MXS_ADC_CHAN(13, IIO_VOLTAGE, "VDDD"),
>> + MXS_ADC_CHAN(14, IIO_VOLTAGE, "VBG"),
>> + MXS_ADC_CHAN(15, IIO_VOLTAGE, "VDD5V"),
>> +};
>> +
>> +static void mxs_lradc_adc_hw_init(struct mxs_lradc_adc *adc)
>> +{
>> + struct mxs_lradc *lradc = adc->lradc;
>> +
>> + /* The ADC always uses DELAY CHANNEL 0. */
>> + const u32 adc_cfg =
>> + (1 << (LRADC_DELAY_TRIGGER_DELAYS_OFFSET + 0)) |
>> + (LRADC_DELAY_TIMER_PER << LRADC_DELAY_DELAY_OFFSET);
>> +
>> + /* Configure DELAY CHANNEL 0 for generic ADC sampling. */
>> + mxs_lradc_reg_wrt(lradc, adc_cfg, LRADC_DELAY(0));
>> +
>> + /* Start internal temperature sensing. */
> We start internal temperature sensing, do we ever want to stop it?

According to manual[1] there is no need to:
To use the internal die temperature sensor,
HW_LRADC_CTRL2_TEMPSENSE_PWD should be cleared. (This bit can be left
cleared after power up. There is no need to toggle it on and off.)

>> + mxs_lradc_reg_wrt(lradc, 0, LRADC_CTRL2);
>> +}
>> +
>> +static void mxs_lradc_adc_hw_stop(struct mxs_lradc_adc *adc)
>> +{
>> + mxs_lradc_reg_wrt(adc->lradc, 0, LRADC_DELAY(0));
>> +}
>> +
>> +static int mxs_lradc_adc_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct mxs_lradc *lradc = dev_get_platdata(dev);
>> + struct mxs_lradc_adc *adc;
>> + struct iio_dev *iio;
>> + int ret, i, s;
>> + u64 scale_uv;
>> +
>> + /* Allocate the IIO device. */
>> + iio = devm_iio_device_alloc(dev, sizeof(*adc));
>> + if (!iio) {
>> + dev_err(dev, "Failed to allocate IIO device\n");
>> + return -ENOMEM;
>> + }
>> +
>> + adc = iio_priv(iio);
>> + adc->lradc = lradc;
>> + adc->dev = dev;
>> +
>> + init_completion(&adc->completion);
>> + mutex_init(&adc->lock);
>> +
>> + for (i = 0; i < lradc->irq_count; i++) {
>> + ret = devm_request_irq(dev, lradc->irq[i],
>> + mxs_lradc_adc_handle_irq,
>> + IRQF_SHARED, lradc->irq_name[i], iio);
>> + if (ret)
>> + return ret;
> This seems to be getting a whole load of irq's whether or not they are actually
> going to be used by the ADC? Aren't some of these going to be typically used by
> the touchscreen?
>> + }
>> +
>> + platform_set_drvdata(pdev, iio);
>> +
>> + iio->name = pdev->name;
>> + iio->dev.parent = dev;
>> + iio->dev.of_node = dev->parent->of_node;
>> + iio->info = &mxs_lradc_adc_iio_info;
>> + iio->modes = INDIO_DIRECT_MODE;
>> + iio->masklength = LRADC_MAX_TOTAL_CHANS;
>> +
>> + if (lradc->soc == IMX23_LRADC) {
>> + iio->channels = mx23_lradc_chan_spec;
>> + iio->num_channels = ARRAY_SIZE(mx23_lradc_chan_spec);
>> + } else {
>> + iio->channels = mx28_lradc_chan_spec;
>> + iio->num_channels = ARRAY_SIZE(mx28_lradc_chan_spec);
>> + }
>> +
>> + ret = iio_triggered_buffer_setup(iio, &iio_pollfunc_store_time,
>> + &mxs_lradc_adc_trigger_handler,
>> + &mxs_lradc_adc_buffer_ops);
>> + if (ret)
>> + return ret;
>> +
>> + ret = mxs_lradc_adc_trigger_init(iio);
>> + if (ret)
>> + goto err_trig;
>> +
>> + adc->vref_mv = mxs_lradc_adc_vref_mv[lradc->soc];
>> +
>> + /* Populate available ADC input ranges */
>> + for (i = 0; i < LRADC_MAX_TOTAL_CHANS; i++) {
>> + for (s = 0; s < ARRAY_SIZE(adc->scale_avail[i]); s++) {
>> + /*
>> + * [s=0] = optional divider by two disabled (default)
>> + * [s=1] = optional divider by two enabled
>> + *
>> + * The scale is calculated by doing:
>> + * Vref >> (realbits - s)
>> + * which multiplies by two on the second component
>> + * of the array.
>> + */
>> + scale_uv = ((u64)adc->vref_mv[i] * 100000000) >>
>> + (LRADC_RESOLUTION - s);
>> + adc->scale_avail[i][s].nano =
>> + do_div(scale_uv, 100000000) * 10;
>> + adc->scale_avail[i][s].integer = scale_uv;
>> + }
>> + }
>> +
>> + /* Configure the hardware. */
>> + mxs_lradc_adc_hw_init(adc);
>> +
>> + /* Register IIO device. */
>> + ret = iio_device_register(iio);
>> + if (ret) {
>> + dev_err(dev, "Failed to register IIO device\n");
>> + goto err_dev;
>> + }
>> +
>> + return 0;
>> +
>> +err_dev:
>> + mxs_lradc_adc_hw_stop(adc);
>> + mxs_lradc_adc_trigger_remove(iio);
>> +err_trig:
>> + iio_triggered_buffer_cleanup(iio);
>> + return ret;
>> +}
>> +
>> +static int mxs_lradc_adc_remove(struct platform_device *pdev)
>> +{
>> + struct iio_dev *iio = platform_get_drvdata(pdev);
>> + struct mxs_lradc_adc *adc = iio_priv(iio);
>> +
>> + iio_device_unregister(iio);
>> + mxs_lradc_adc_hw_stop(adc);
>> + mxs_lradc_adc_trigger_remove(iio);
>> + iio_triggered_buffer_cleanup(iio);
>> +
>> + return 0;
>> +}
>> +
>> +static struct platform_driver mxs_lradc_adc_driver = {
>> + .driver = {
>> + .name = DRIVER_NAME_ADC,
>> + },
>> + .probe = mxs_lradc_adc_probe,
>> + .remove = mxs_lradc_adc_remove,
>> +};
>> +
>> +module_platform_driver(mxs_lradc_adc_driver);
>> +
>> +MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
>> +MODULE_DESCRIPTION("Freescale MXS LRADC driver general purpose ADC driver");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_ALIAS("platform:" DRIVER_NAME_ADC);
>> +
> Bonus blank line at end of file...
>> +
>>
>
[1] http://cache.freescale.com/files/dsp/doc/ref_manual/MCIMX28RM.pdf

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