Date:	Fri, 31 Oct 2014 21:48:55 +0100 (CET)
From:	Peter Meerwald <pmeerw@...erw.net>
To:	"Ivan T. Ivanov" <iivanov@...sol.com>,
	Hartmut Knaack <knaack.h@....de>
cc:	Jonathan Cameron <jic23@...nel.org>,
	Lars-Peter Clausen <lars@...afoo.de>,
	linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v4] iio: iadc: Qualcomm SPMI PMIC current ADC driver


> Ivan T. Ivanov schrieb am 22.10.2014 16:13:
> > The current ADC is peripheral of Qualcomm SPMI PMIC chips. It has
> > 16 bits resolution and register space inside PMIC accessible across
> > SPMI bus.
> > 
> > The driver registers itself through IIO interface.
> Pretty much there, just one question I would like to double-check: The CPU of these chips is Little Endian, right?
> Annoyingly, you introduced a small typo in this revision, but that alone doesn't qualify for a new revision. A separate patch fixing it would probably be best. See inline.

some minor comments below

> > Signed-off-by: Ivan T. Ivanov <iivanov@...sol.com>
> > ---
> > 
> > Changes:
> >  - Address review comments from Hartmut Knaack
> > 
> >  .../devicetree/bindings/iio/adc/qcom,spmi-iadc.txt |  46 ++
> >  drivers/iio/adc/Kconfig                            |  14 +
> >  drivers/iio/adc/Makefile                           |   1 +
> >  drivers/iio/adc/qcom-spmi-iadc.c                   | 595 +++++++++++++++++++++
> >  4 files changed, 656 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/adc/qcom,spmi-iadc.txt
> >  create mode 100644 drivers/iio/adc/qcom-spmi-iadc.c
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-iadc.txt b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-iadc.txt
> > new file mode 100644
> > index 0000000..4e36d6e
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-iadc.txt
> > @@ -0,0 +1,46 @@
> > +Qualcomm's SPMI PMIC current ADC
> > +
> > +QPNP PMIC current ADC (IADC) provides interface to clients to read current.
> > +A 16 bit ADC is used for current measurements. IADC can measure the current
> > +through an external resistor (channel 1) or internal (built-in) resistor
> > +(channel 0). When using an external resistor it is to be described by
> > +qcom,external-resistor-micro-ohms property.
> > +
> > +IADC node:
> > +
> > +- compatible:
> > +    Usage: required
> > +    Value type: <string>
> > +    Definition: Should contain "qcom,spmi-iadc".
> > +
> > +- reg:
> > +    Usage: required
> > +    Value type: <prop-encoded-array>
> > +    Definition: IADC base address and length in the SPMI PMIC register map
> > +
> > +- interrupts:
> > +    Usage: optional
> > +    Value type: <prop-encoded-array>
> > +    Definition: End of ADC conversion.
> > +
> > +- qcom,external-resistor-micro-ohms:
> > +    Usage: optional
> > +    Value type: <u32>
> > +    Definition: Sense resister value in micro Ohm.
> > +                If not defined value of 10000 micro Ohms will be used.
> > +
> > +Example:
> > +	/* IADC node */
> > +	pmic_iadc: iadc@...0 {
> > +		compatible = "qcom,spmi-iadc";
> > +		reg = <0x3600 0x100>;
> > +		interrupts = <0x0 0x36 0x0 IRQ_TYPE_EDGE_RISING>;
> > +		qcom,external-resistor-micro-ohms = <10000>;
> > +		#io-channel-cells  = <1>;
> > +	};
> > +
> > +	/* IIO client node */
> > +	bat {
> > +		io-channels = <&pmic_iadc  0>;
> > +		io-channel-names = "iadc";
> > +	};
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index 88bdc8f..d0924f3 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -206,6 +206,20 @@ config NAU7802
> >  	  To compile this driver as a module, choose M here: the
> >  	  module will be called nau7802.
> >  
> > +config QCOM_SPMI_IADC
> > +	tristate "Qualcomm SPMI PMIC current ADC"
> > +	depends on SPMI
> > +	select REGMAP_SPMI
> > +	help
> > +	  This is the IIO Current ADC driver for Qualcomm QPNP IADC Chip.
> > +
> > +	  The driver supports single mode operation to read from one of two
> > +	  channels (external or internal). Hardware have additional
> > +	  channels internally used for gain and offset calibration.
> > +
> > +	  To compile this driver as a module, choose M here: the module will
> > +	  be called qcom-spmi-iadc.
> > +
> >  config ROCKCHIP_SARADC
> >  	tristate "Rockchip SARADC driver"
> >  	depends on ARCH_ROCKCHIP || (ARM && COMPILE_TEST)
> > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > index cb88a6a..c06718b 100644
> > --- a/drivers/iio/adc/Makefile
> > +++ b/drivers/iio/adc/Makefile
> > @@ -22,6 +22,7 @@ obj-$(CONFIG_MCP320X) += mcp320x.o
> >  obj-$(CONFIG_MCP3422) += mcp3422.o
> >  obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
> >  obj-$(CONFIG_NAU7802) += nau7802.o
> > +obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
> >  obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
> >  obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
> >  obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
> > diff --git a/drivers/iio/adc/qcom-spmi-iadc.c b/drivers/iio/adc/qcom-spmi-iadc.c
> > new file mode 100644
> > index 0000000..b9666f2
> > --- /dev/null
> > +++ b/drivers/iio/adc/qcom-spmi-iadc.c
> > @@ -0,0 +1,595 @@
> > +/*
> > + * Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 and
> > + * only version 2 as published by the Free Software Foundation.
> > + *
> > + * 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/completion.h>
> > +#include <linux/delay.h>
> > +#include <linux/err.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mutex.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +#include <linux/slab.h>
> > +
> > +/* IADC register and bit definition */
> > +#define IADC_REVISION2				0x1
> > +#define IADC_REVISION2_SUPPORTED_IADC		1
> > +
> > +#define IADC_PERPH_TYPE				0x4
> > +#define IADC_PERPH_TYPE_ADC			8
> > +
> > +#define IADC_PERPH_SUBTYPE			0x5
> > +#define IADC_PERPH_SUBTYPE_IADC			3
> > +
> > +#define IADC_STATUS1				0x8
> > +#define IADC_STATUS1_OP_MODE			4
> > +#define IADC_STATUS1_REQ_STS			BIT(1)
> > +#define IADC_STATUS1_EOC			BIT(0)
> > +#define IADC_STATUS1_REQ_STS_EOC_MASK		0x3
> > +
> > +#define IADC_MODE_CTL				0x40
> > +#define IADC_OP_MODE_SHIFT			3
> > +#define IADC_OP_MODE_NORMAL			0
> > +#define IADC_TRIM_EN				BIT(0)
> > +
> > +#define IADC_EN_CTL1				0x46
> > +#define IADC_EN_CTL1_SET			BIT(7)
> > +
> > +#define IADC_CH_SEL_CTL				0x48
> > +
> > +#define IADC_DIG_PARAM				0x50
> > +#define IADC_DIG_DEC_RATIO_SEL_SHIFT		2
> > +
> > +#define IADC_HW_SETTLE_DELAY			0x51
> > +
> > +#define IADC_CONV_REQ				0x52
> > +#define IADC_CONV_REQ_SET			BIT(7)
> > +
> > +#define IADC_FAST_AVG_CTL			0x5a
> > +#define IADC_FAST_AVG_EN			0x5b
> > +#define IADC_FAST_AVG_EN_SET			BIT(7)
> > +
> > +#define IADC_PERH_RESET_CTL3			0xda
> > +#define IADC_FOLLOW_WARM_RB			BIT(2)
> > +
> > +#define IADC_DATA				0x60	/* 16 bits */
> > +
> > +#define IADC_SEC_ACCESS				0xd0
> > +#define IADC_SEC_ACCESS_DATA			0xa5
> > +
> > +#define IADC_NOMINAL_RSENSE			0xf4
> > +#define IADC_NOMINAL_RSENSE_SIGN_MASK		BIT(7)
> > +
> > +#define IADC_REF_GAIN_MICRO_VOLTS		17857
> > +
> > +#define IADC_INT_RSENSE_DEVIATION		15625	/* nano Ohms per bit */
> > +
> > +#define IADC_INT_RSENSE_IDEAL_VALUE		10000	/* micro Ohms */
> > +#define IADC_INT_RSENSE_DEFAULT_VALUE		7800	/* micro Ohms */
> > +#define IADC_INT_RSENSE_DEFAULT_GF		9000	/* micro Ohms */
> > +#define IADC_INT_RSENSE_DEFAULT_SMIC		9700	/* micro Ohms */
> > +
> > +#define IADC_CONV_TIME_MIN_US			2000
> > +#define IADC_CONV_TIME_MAX_US			2100
> > +
> > +#define IADC_DEF_PRESCALING			0 /* 1:1 */
> > +#define IADC_DEF_DECIMATION			0 /* 512 */
> > +#define IADC_DEF_HW_SETTLE_TIME			0 /* 0 us */
> > +#define IADC_DEF_AVG_SAMPLES			0 /* 1 sample */
> > +
> > +/* IADC channel list */
> > +#define IADC_INT_RSENSE				0
> > +#define IADC_EXT_RSENSE				1
> > +#define IADC_GAIN_17P857MV			3
> > +#define IADC_EXT_OFFSET_CSP_CSN			5
> > +#define IADC_INT_OFFSET_CSP2_CSN2		6
> > +
> > +/**
> > + * struct iadc_chip - IADC Current ADC device structure.
> > + * @regmap: regmap for register read/write.
> > + * @dev: This device pointer.
> > + * @base: base offset for the ADC peripheral.
> > + * @rsense: Values of the internal and external sense resister in micro Ohms.
> > + * @poll_eoc: Poll for end of conversion instead of waiting for IRQ.
> > + * @offset: Raw offset values for the internal and external channels.

would be nice if the order matches the struct

> > + * @gain: Raw gain of the channels.
> > + * @lock: ADC lock for access to the peripheral.
> > + * @complete: ADC notification after end of conversion interrupt is received.
> > + */
> > +struct iadc_chip {
> > +	struct regmap	*regmap;
> > +	struct device	*dev;
> > +	u16		base;
> > +	bool		poll_eoc;
> > +	u32		rsense[2];
> > +	u16		offset[2];
> > +	u16		gain;
> > +	struct mutex	lock;
> > +	struct completion complete;
> > +};
> > +
> > +static int iadc_read(struct iadc_chip *iadc, u16 offset, u8 *data)
> > +{
> > +	unsigned int val;
> > +	int ret;
> > +
> > +	ret = regmap_read(iadc->regmap, iadc->base + offset, &val);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	*data = val;
> > +	return 0;
> > +}
> > +
> > +static int iadc_write(struct iadc_chip *iadc, u16 offset, u8 data)
> > +{
> > +	return regmap_write(iadc->regmap, iadc->base + offset, data);
> > +}
> > +
> > +static int iadc_reset(struct iadc_chip *iadc)
> > +{
> > +	u8 data;
> > +	int ret;
> > +
> > +	ret = iadc_write(iadc, IADC_SEC_ACCESS, IADC_SEC_ACCESS_DATA);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = iadc_read(iadc, IADC_PERH_RESET_CTL3, &data);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = iadc_write(iadc, IADC_SEC_ACCESS, IADC_SEC_ACCESS_DATA);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	data |= IADC_FOLLOW_WARM_RB;
> > +
> > +	return iadc_write(iadc, IADC_PERH_RESET_CTL3, data);
> > +}
> > +
> > +static int iadc_set_state(struct iadc_chip *iadc, bool state)
> > +{
> > +	return iadc_write(iadc, IADC_EN_CTL1, state ? IADC_EN_CTL1_SET : 0);
> > +}
> > +
> > +static void iadc_status_show(struct iadc_chip *iadc)
> > +{
> > +	u8 mode, sta1, chan, dig, en, req;
> > +	int ret;
> > +
> > +	ret = iadc_read(iadc, IADC_MODE_CTL, &mode);
> > +	if (ret < 0)
> > +		return;
> > +
> > +	ret = iadc_read(iadc, IADC_DIG_PARAM, &dig);
> > +	if (ret < 0)
> > +		return;
> > +
> > +	ret = iadc_read(iadc, IADC_CH_SEL_CTL, &chan);
> > +	if (ret < 0)
> > +		return;
> > +
> > +	ret = iadc_read(iadc, IADC_CONV_REQ, &req);
> > +	if (ret < 0)
> > +		return;
> > +
> > +	ret = iadc_read(iadc, IADC_STATUS1, &sta1);
> > +	if (ret < 0)
> > +		return;
> > +
> > +	ret = iadc_read(iadc, IADC_EN_CTL1, &en);
> > +	if (ret < 0)
> > +		return;
> > +
> > +	dev_err(iadc->dev,
> > +		"mode:%02x en:%02x chan:%02x dig:%02x req:%02x sta1:%02x\n",
> > +		mode, en, chan, dig, req, sta1);
> > +}
> > +
> > +static int iadc_configure(struct iadc_chip *iadc, int channel)
> > +{
> > +	u8 decim, mode;
> > +	int ret;
> > +
> > +	/* Mode selection */
> > +	mode = (IADC_OP_MODE_NORMAL << IADC_OP_MODE_SHIFT) | IADC_TRIM_EN;
> > +	ret = iadc_write(iadc, IADC_MODE_CTL, mode);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	/* Channel selection */
> > +	ret = iadc_write(iadc, IADC_CH_SEL_CTL, channel);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	/* Digital parameter setup */
> > +	decim = IADC_DEF_DECIMATION << IADC_DIG_DEC_RATIO_SEL_SHIFT;
> > +	ret = iadc_write(iadc, IADC_DIG_PARAM, decim);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	/* HW settle time delay */
> > +	ret = iadc_write(iadc, IADC_HW_SETTLE_DELAY, IADC_DEF_HW_SETTLE_TIME);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = iadc_write(iadc, IADC_FAST_AVG_CTL, IADC_DEF_AVG_SAMPLES);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	if (IADC_DEF_AVG_SAMPLES)

a bit unusual to check a #define

> > +		ret = iadc_write(iadc, IADC_FAST_AVG_EN, IADC_FAST_AVG_EN_SET);
> > +	else
> > +		ret = iadc_write(iadc, IADC_FAST_AVG_EN, 0);
> > +
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	if (!iadc->poll_eoc)
> > +		reinit_completion(&iadc->complete);
> > +
> > +	ret = iadc_set_state(iadc, true);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	/* Request conversion */
> > +	return iadc_write(iadc, IADC_CONV_REQ, IADC_CONV_REQ_SET);
> > +}
> > +
> > +static int iadc_poll_wait_eoc(struct iadc_chip *iadc, unsigned int interval_us)
> > +{
> > +	unsigned int count, retry;
> > +	int ret;
> > +	u8 sta1;
> > +
> > +	retry = interval_us / IADC_CONV_TIME_MIN_US;
> > +
> > +	for (count = 0; count < retry; count++) {
> > +		ret = iadc_read(iadc, IADC_STATUS1, &sta1);
> > +		if (ret < 0)
> > +			return ret;
> > +
> > +		sta1 &= IADC_STATUS1_REQ_STS_EOC_MASK;
> > +		if (sta1 == IADC_STATUS1_EOC)
> > +			return 0;
> > +
> > +		usleep_range(IADC_CONV_TIME_MIN_US, IADC_CONV_TIME_MAX_US);
> > +	}
> > +
> > +	iadc_status_show(iadc);
> > +
> > +	return -ETIMEDOUT;
> > +}
> > +
> > +static int iadc_read_result(struct iadc_chip *iadc, u16 *data)
> > +{
> > +	return regmap_bulk_read(iadc->regmap, iadc->base + IADC_DATA, data, 2);
> > +}
> > +
> > +static int iadc_do_conversion(struct iadc_chip *iadc, int chan, u16 *data)
> > +{
> > +	unsigned int wait;
> > +	int ret;
> > +
> > +	ret = iadc_configure(iadc, chan);
> > +	if (ret < 0)
> > +		goto exit;
> > +
> > +	wait = BIT(IADC_DEF_AVG_SAMPLES) * IADC_CONV_TIME_MIN_US * 2;
> > +
> > +	if (iadc->poll_eoc) {
> > +		ret = iadc_poll_wait_eoc(iadc, wait);
> > +	} else {
> > +		ret = wait_for_completion_timeout(&iadc->complete, wait);
> > +		if (!ret)
> > +			ret = -ETIMEDOUT;
> > +		else
> > +			/* double check conversion status */

Double check...

> > +			ret = iadc_poll_wait_eoc(iadc, IADC_CONV_TIME_MIN_US);
> > +	}
> > +
> > +	if (!ret)
> > +		ret = iadc_read_result(iadc, data);
> > +exit:
> > +	iadc_set_state(iadc, false);
> > +	if (ret < 0)
> > +		dev_err(iadc->dev, "conversion failed\n");
> > +
> > +	return ret;
> > +}
> > +
> > +static int iadc_read_raw(struct iio_dev *indio_dev,
> > +			 struct iio_chan_spec const *chan,
> > +			 int *val, int *val2, long mask)
> > +{
> > +	struct iadc_chip *iadc = iio_priv(indio_dev);
> > +	s32 isense_ua, vsense_uv;
> > +	u16 adc_raw, vsense_raw;
> > +	int ret;
> > +
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_RAW:
> > +		mutex_lock(&iadc->lock);
> > +		ret = iadc_do_conversion(iadc, chan->channel, &adc_raw);
> > +		mutex_unlock(&iadc->lock);
> > +		if (ret < 0)
> > +			return ret;
> > +
> > +		vsense_raw = adc_raw - iadc->offset[chan->channel];
> > +
> > +		vsense_uv = vsense_raw * IADC_REF_GAIN_MICRO_VOLTS;
> > +		vsense_uv /= (s32)iadc->gain - iadc->offset[chan->channel];
> > +
> > +		isense_ua = vsense_uv / iadc->rsense[chan->channel];
> > +
> > +		dev_dbg(iadc->dev, "off %d gain %d adc %d %duV I %duA\n",
> > +			iadc->offset[chan->channel], iadc->gain,
> > +			adc_raw, vsense_uv, isense_ua);
> > +
> > +		*val = isense_ua;
> > +		return IIO_VAL_INT;
> > +	case IIO_CHAN_INFO_SCALE:
> > +		*val = 0;
> > +		*val2 = 1000;
> > +		return IIO_VAL_INT_PLUS_MICRO;
> > +	}
> > +
> > +	return -EINVAL;
> > +}
> > +
> > +static const struct iio_info iadc_info = {
> > +	.read_raw = iadc_read_raw,
> > +	.driver_module = THIS_MODULE,
> > +};
> > +
> > +static irqreturn_t iadc_isr(int irq, void *dev_id)
> > +{
> > +	struct iadc_chip *iadc = dev_id;
> > +
> > +	complete(&iadc->complete);
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static int iadc_update_offset(struct iadc_chip *iadc)
> > +{
> > +	int ret;
> > +
> > +	ret = iadc_do_conversion(iadc, IADC_GAIN_17P857MV, &iadc->gain);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = iadc_do_conversion(iadc, IADC_INT_OFFSET_CSP2_CSN2,
> > +				 &iadc->offset[IADC_INT_RSENSE]);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	if (iadc->gain == iadc->offset[IADC_INT_RSENSE]) {
> > +		dev_err(iadc->dev, "error: internal offset == gain %d\n",
> > +			iadc->gain);
> > +		return -EINVAL;
> > +	}
> > +
> > +	ret = iadc_do_conversion(iadc, IADC_EXT_OFFSET_CSP_CSN,
> > +				 &iadc->offset[IADC_EXT_RSENSE]);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	if (iadc->gain == iadc->offset[IADC_EXT_RSENSE]) {
> > +		dev_err(iadc->dev, "error: external offset == gain %d\n",
> > +			iadc->gain);
> > +		return -EINVAL;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int iadc_version_check(struct iadc_chip *iadc)
> > +{
> > +	u8 val;
> > +	int ret;
> > +
> > +	ret = iadc_read(iadc, IADC_PERPH_TYPE, &val);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	if (val < IADC_PERPH_TYPE_ADC) {
> > +		dev_err(iadc->dev, "%d is not ADC\n", val);
> > +		return -EINVAL;
> > +	}
> > +
> > +	ret = iadc_read(iadc, IADC_PERPH_SUBTYPE, &val);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	if (val < IADC_PERPH_SUBTYPE_IADC) {
> > +		dev_err(iadc->dev, "%d is not IADC\n", val);
> > +		return -EINVAL;
> > +	}
> > +
> > +	ret = iadc_read(iadc, IADC_REVISION2, &val);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	if (val < IADC_REVISION2_SUPPORTED_IADC) {
> > +		dev_err(iadc->dev, "revision %d not supported\n", val);
> > +		return -EINVAL;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int iadc_rsense_read(struct iadc_chip *iadc, struct device_node *node)
> > +{
> > +	int ret, sign, int_sense;
> > +	u8 deviation;
> > +
> > +	ret = of_property_read_u32(node, "qcom,external-resistor-micro-ohms",
> > +				   &iadc->rsense[IADC_EXT_RSENSE]);
> > +	if (ret < 0)
> > +		iadc->rsense[IADC_EXT_RSENSE] = IADC_INT_RSENSE_IDEAL_VALUE;
> > +
> > +	if (!iadc->rsense[IADC_EXT_RSENSE]) {
> > +		dev_err(iadc->dev, "external resistor can't be zero Ohms");
> > +		return -EINVAL;
> > +	}
> > +
> > +	ret = iadc_read(iadc, IADC_NOMINAL_RSENSE, &deviation);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	/*
> > +	 * Deviation value stored is an offset from 10 mili Ohms, bit 7 is

milli

> > +	 * the sign, the remaining bits have an LSB of 15625 nano Ohms.
> > +	 */
> > +	sign = (deviation & IADC_NOMINAL_RSENSE_SIGN_MASK) ? -1 : 1;
> > +
> > +	deviation &= ~IADC_NOMINAL_RSENSE_SIGN_MASK;
> > +
> > +	/* Scale it to nono Ohms */
> Typo: nano
> > +	int_sense = IADC_INT_RSENSE_IDEAL_VALUE * 1000;
> > +	int_sense += sign * deviation * IADC_INT_RSENSE_DEVIATION;
> > +	int_sense /= 1000; /* micro Ohms */
> > +
> > +	iadc->rsense[IADC_INT_RSENSE] = int_sense;
> > +	return 0;
> > +}
> > +
> > +static const struct iio_chan_spec iadc_channels[] = {
> > +	{
> > +		.type = IIO_CURRENT,
> > +		.datasheet_name	= "INTERNAL_RSENSE",
> > +		.channel = 0,
> > +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> > +				      BIT(IIO_CHAN_INFO_SCALE),
> > +		.indexed = 1,
> > +	},
> > +	{
> > +		.type = IIO_CURRENT,
> > +		.datasheet_name	= "EXTERNAL_RSENSE",
> > +		.channel = 1,
> > +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> > +				      BIT(IIO_CHAN_INFO_SCALE),
> > +		.indexed = 1,
> > +	},
> > +};
> > +
> > +static int iadc_probe(struct platform_device *pdev)
> > +{
> > +	struct device_node *node = pdev->dev.of_node;
> > +	struct device *dev = &pdev->dev;
> > +	struct iio_dev *indio_dev;
> > +	struct iadc_chip *iadc;
> > +	int ret, irq_eoc;
> > +	u32 res;
> > +
> > +	indio_dev = devm_iio_device_alloc(dev, sizeof(*iadc));
> > +	if (!indio_dev)
> > +		return -ENOMEM;
> > +
> > +	iadc = iio_priv(indio_dev);
> > +	iadc->dev = dev;
> > +
> > +	iadc->regmap = dev_get_regmap(dev->parent, NULL);
> > +	if (!iadc->regmap)
> > +		return -ENODEV;
> > +
> > +	init_completion(&iadc->complete);
> > +	mutex_init(&iadc->lock);
> > +
> > +	ret = of_property_read_u32(node, "reg", &res);
> > +	if (ret < 0)
> > +		return -ENODEV;
> > +
> > +	iadc->base = res;
> > +
> > +	ret = iadc_version_check(iadc);
> > +	if (ret < 0)
> > +		return -ENODEV;
> > +
> > +	ret = iadc_rsense_read(iadc, node);
> > +	if (ret < 0)
> > +		return -ENODEV;
> > +
> > +	dev_dbg(iadc->dev, "sense resistors %d and %d micro Ohm\n",
> > +		iadc->rsense[IADC_INT_RSENSE],
> > +		iadc->rsense[IADC_EXT_RSENSE]);
> > +
> > +	irq_eoc = platform_get_irq(pdev, 0);
> > +	if (irq_eoc == -EPROBE_DEFER)
> > +		return irq_eoc;
> > +
> > +	if (irq_eoc < 0)
> > +		iadc->poll_eoc = true;
> > +
> > +	ret = iadc_reset(iadc);
> > +	if (ret < 0) {
> > +		dev_err(dev, "reset failed\n");
> > +		return ret;
> > +	}
> > +
> > +	if (!iadc->poll_eoc) {
> > +		ret = devm_request_irq(dev, irq_eoc, iadc_isr, 0,
> > +					"spmi-iadc", iadc);
> > +		if (!ret)
> > +			enable_irq_wake(irq_eoc);
> > +		else
> > +			return ret;
> > +	} else {
> > +		device_init_wakeup(iadc->dev, 1);
> > +	}
> > +
> > +	ret = iadc_update_offset(iadc);
> > +	if (ret < 0) {
> > +		dev_err(dev, "failed offset calibration\n");
> > +		return ret;
> > +	}
> > +
> > +	indio_dev->dev.parent = dev;
> > +	indio_dev->dev.of_node = node;
> > +	indio_dev->name = pdev->name;
> > +	indio_dev->modes = INDIO_DIRECT_MODE;
> > +	indio_dev->info = &iadc_info;
> > +	indio_dev->channels = iadc_channels;
> > +	indio_dev->num_channels = ARRAY_SIZE(iadc_channels);
> > +
> > +	return devm_iio_device_register(dev, indio_dev);
> > +}
> > +
> > +static const struct of_device_id iadc_match_table[] = {
> > +	{ .compatible = "qcom,spmi-iadc" },
> > +	{ }
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, iadc_match_table);
> > +
> > +static struct platform_driver iadc_driver = {
> > +	.driver = {
> > +		   .name = "qcom-spmi-iadc",
> > +		   .of_match_table = iadc_match_table,
> > +	},
> > +	.probe = iadc_probe,
> > +};
> > +
> > +module_platform_driver(iadc_driver);
> > +
> > +MODULE_ALIAS("platform:qcom-spmi-iadc");
> > +MODULE_DESCRIPTION("Qualcomm SPMI PMIC current ADC driver");
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_AUTHOR("Ivan T. Ivanov <iivanov@...sol.com>");
> > 
> 
> --
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> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)
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