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SubjectRe: [PATCH 2/3] iio: adc: mxs-lradc: Add support for adc driver
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Date
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?
> + 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...
> +
>

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