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Date: Sun, 21 Sep 2014 15:04:21 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: "Ivan T. Ivanov" <iivanov@...sol.com>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Grant Likely <grant.likely@...aro.org>
CC: Lars-Peter Clausen <lars@...afoo.de>,
Hartmut Knaack <knaack.h@....de>,
Lee Jones <lee.jones@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-iio@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH] iio: iadc: Qualcomm SPMI PMIC current ADC driver
On 18/09/14 14:15, Ivan T. Ivanov wrote:
> 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.
>
> Signed-off-by: Ivan T. Ivanov <iivanov@...sol.com>
A few comments from me inline...
> ---
> .../devicetree/bindings/iio/adc/qcom,spmi-iadc.txt | 61 ++
> drivers/iio/adc/Kconfig | 11 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/qcom-spmi-iadc.c | 700 +++++++++++++++++++++
> 4 files changed, 773 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..77be22a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-iadc.txt
> @@ -0,0 +1,61 @@
> +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 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.
> + TRIM_CNST_RDS register address and length(1)
> +
> +- interrupts:
> + Usage: optional
> + Value type: <prop-encoded-array>
> + Definition: End of conversion interrupt number. If property is
> + missing driver will use polling to detect end of conversion
> + completion.
> +
> +- qcom,rsense:
> + Usage: optional
> + Value type: <u32>
> + Definition: External sense register value in Ohm. Defining this
> + propery will instruct ADC to use external ADC sense channel.
> + If property is not defined ADC will use internal sense channel.
> +
> +- qcom,rds-trim:
> + Usage: optional
> + Value type: <u32>
> + Definition: Calaculate internal sense resistor value based TRIM_CNST_RDS,
calculate?
> + IADC RDS and manufacturer type.
> + 0: Read the IADC and SMBB trim register and apply the default
> + RSENSE if conditions are met.
> + 1: Read the IADC, SMBB trim register and manufacturer type and
> + apply the default RSENSE if conditions are met.
> + 2: Read the IADC, SMBB trim register and apply the default RSENSE
> + if conditions are met.
> + If property is not defined driver will use qcom,rsense value if
> + defined or internal sense resistor value trimmed into register.
> +
> +Example:
> + /* IADC node */
> + pmic_iadc: iadc@...0 {
> + compatible = "qcom,spmi-iadc";
> + reg = <0x3600 0x100>,
> + <0x12f1 0x1>;
> + interrupts = <0x0 0x36 0x0 IRQ_TYPE_EDGE_RISING>;
> + qcom,rds-trim = <0>;
> + };
> +
> + /* 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 11b048a..77274e4 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -279,4 +279,15 @@ config XILINX_XADC
> The driver can also be build as a module. If so, the module will be called
> xilinx-xadc.
>
> +config QCOM_SPMI_IADC
> + tristate "Qualcomm SPMI PMIC current ADC"
> + select REGMAP_SPMI
> + depends on IIO
> + help
> + This is the IIO Current ADC driver for Qualcomm QPNP IADC Chip.
> +
> + The driver supports single mode operation to read from upto seven channel
channels? You only seem to register one...
> + configuration that include reading the external/internal Rsense, CSP_EX,
> + CSN_EX pair along with the gain and offset calibration.
> +
> endmenu
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index ad81b51..c790543 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -30,3 +30,4 @@ obj-$(CONFIG_VF610_ADC) += vf610_adc.o
> obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
> xilinx-xadc-y := xilinx-xadc-core.o xilinx-xadc-events.o
> obj-$(CONFIG_XILINX_XADC) += xilinx-xadc.o
> +obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.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..fef9168
> --- /dev/null
> +++ b/drivers/iio/adc/qcom-spmi-iadc.c
> @@ -0,0 +1,700 @@
> +/*
> + * 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/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +/* IADC 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_DATA0 0x60
> +#define IADC_DATA1 0x61
> +
> +#define IADC_SEC_ACCESS 0xd0
> +#define IADC_SEC_ACCESS_DATA 0xa5
> +
> +#define IADC_INT_TEST_VAL 0xe1
> +#define IADC_MSB_OFFSET 0xf2
> +#define IADC_LSB_OFFSET 0xf3
> +
> +#define IADC_NOMINAL_RSENSE 0xf4
> +#define IADC_NOMINAL_RSENSE_SIGN_MASK BIT(7)
> +
> +#define IADC_REF_GAIN_MICRO_VOLTS 17857
> +
> +#define IADC_INTERNAL_RSENSE_OHMS 10000000
> +#define IADC_RSENSE_OHMS_PER_BIT 15625
> +
> +#define IADC_TRIM_CNST_RDS_MASK 0x7
> +
> +#define IADC_FACTORY_GF 0
> +#define IADC_FACTORY_SMIC 1
> +#define IADC_FACTORY_TSMC 2
> +
> +#define IADC_TRIM2_FULLSCALE 127
> +
> +#define IADC_RSENSE_DEFAULT_VALUE 7800000
> +#define IADC_RSENSE_DEFAULT_GF 9000000
> +#define IADC_RSENSE_DEFAULT_SMIC 9700000
> +
> +#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 IADC channel list */
> +#define IADC_INTERNAL_RSENSE 0
> +#define IADC_EXTERNAL_RSENSE 1
> +#define IADC_ALT_LEAD_PAIR 2
> +#define IADC_GAIN_17P857MV 3
> +#define IADC_OFFSET_SHORT_CADC_LEADS 4
> +#define IADC_OFFSET_CSP_CSN 5
> +#define IADC_OFFSET_CSP2_CSN2 6
> +#define IADC_CHANNEL_COUNT 7
> +
> +/**
> + * struct iadc_drv - IADC Current ADC device structure.
> + * @regmap: regmap for register read/write.
> + * @dev: This device pointer.
> + * @factory: Chip manufacturer.
> + * @base: base offset for the ADC peripheral.
> + * @trim_rds: Address of the Trim Constant Rds register.
> + * @rsense: Sense register in Ohms.
> + * @ext_sense: Using external sense resistor.
> + * @poll_eoc: Poll for end of conversion instead of waiting for IRQ.
> + * @offset_raw: Raw offset value for the channel.
> + * @gain_raw: Raw gain of the channel.
> + * @lock: ADC lock for access to the peripheral.
> + * @complete: ADC notification after end of conversion interrupt is received.
> + * @iio_chan: IIO channel as registered into framework.
> + */
> +struct iadc_chip {
> + struct regmap *regmap;
> + struct device *dev;
> + u8 factory;
> + u16 base;
> + u16 trim_rds;
> + int rsense;
> + bool ext_sense;
> + bool poll_eoc;
> + u16 offset_raw;
> + u16 gain_raw;
> + struct mutex lock;
> + struct completion complete;
> + struct iio_chan_spec iio_chan;
As explained below, better to have this as static const outside of
here.
> +};
> +
> +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)
> + *data = val;
> +
> + return ret;
> +}
Borderline whether these wrappers add significant value... I suppose they
hide the application of the offset.
> +
> +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_enable(struct iadc_chip *iadc, bool state)
iadc_set_state prefered as enable(false) does not necessarily mean
disable.
> +{
> + u8 data = 0;
> +
> + if (state)
> + data = IADC_EN_CTL1_SET;
> +
> + return iadc_write(iadc, IADC_EN_CTL1, data);
> +}
> +
> +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_warn(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)
> + 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_enable(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, int interval_us)
> +{
> + int ret, count, retry;
> + 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);
What is this for? Left over from debugging the driver?
> +
> + return -ETIMEDOUT;
> +}
> +
> +static int iadc_read_result(struct iadc_chip *iadc, u16 *data)
> +{
> + u8 lsb, msb;
> + int ret;
> +
> + ret = iadc_read(iadc, IADC_DATA0, &lsb);
> + if (ret < 0)
> + return ret;
> +
> + ret = iadc_read(iadc, IADC_DATA1, &msb);
> + if (ret < 0)
> + return ret;
> +
> + *data = (msb << 8) | lsb;
> +
> + return 0;
> +}
> +
> +static int iadc_do_conversion(struct iadc_chip *iadc, int chan, u16 *data)
> +{
> + int wait, 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 */
> + ret = iadc_poll_wait_eoc(iadc, IADC_CONV_TIME_MIN_US);
> + }
> +
> + if (!ret)
> + ret = iadc_read_result(iadc, data);
> +exit:
> + iadc_enable(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);
> + long rsense_ua, rsense_uv, rsense_raw;
> + int ret = -EINVAL, negative;
> + u16 adc_raw;
> +
> + mutex_lock(&iadc->lock);
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_PROCESSED:
> + ret = iadc_do_conversion(iadc, chan->channel, &adc_raw);
> + if (ret < 0)
> + goto exit;
> +
> + rsense_raw = adc_raw - iadc->offset_raw;
> +
> + rsense_uv = (rsense_raw * IADC_REF_GAIN_MICRO_VOLTS);
> + rsense_uv /= iadc->gain_raw - iadc->offset_raw;
> +
> + negative = 0;
> + if (rsense_uv < 0) {
> + negative = 1;
> + rsense_uv = -rsense_uv;
> + }
> +
> + rsense_ua = rsense_uv;
> +
> + do_div(rsense_ua, iadc->rsense);
> +
> + if (negative)
> + rsense_ua = -rsense_ua;
> +
> + dev_dbg(iadc->dev, "offset %d, gain %d, adc %d, V=%ld,uV, I=%ld,uA\n",
> + iadc->offset_raw, iadc->gain_raw, adc_raw,
> + rsense_uv, rsense_ua);
> +
> + *val = rsense_ua;
Given the naming this seems unlikely to be in millamps?
> + ret = IIO_VAL_INT;
> + break;
> + default:
> + break;
> + }
> +
> +exit:
> + mutex_unlock(&iadc->lock);
> +
> + return ret;
> +}
> +
> +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_trim_offset(struct iadc_chip *iadc)
> +{
> + u16 adc_raw;
> + u8 lsb, msb;
> + int ret, chan;
> +
> + ret = iadc_do_conversion(iadc, IADC_GAIN_17P857MV, &adc_raw);
> + if (ret < 0)
> + return ret;
> +
> + iadc->gain_raw = adc_raw;
There is no real purpose in having the local variable adc_raw.
It won't get written unless everything is fine anyway so why
not use iadc->gain_raw directly in the do_conversion call.
> +
> + chan = IADC_OFFSET_CSP2_CSN2;
> + if (iadc->ext_sense)
> + chan = IADC_OFFSET_CSP_CSN;
> +
> + ret = iadc_do_conversion(iadc, chan, &adc_raw);
> + if (ret < 0)
> + return ret;
> +
> + iadc->offset_raw = adc_raw;
> +
> + if ((iadc->gain_raw - iadc->offset_raw) == 0) {
> + dev_err(iadc->dev, "error: offset %d gain %d\n",
> + iadc->offset_raw, iadc->gain_raw);
> + return -EINVAL;
> + }
> +
> + msb = adc_raw >> 8;
> + lsb = adc_raw & 0xff;
Do these directly where needed rather than bothering with local
variables.
> +
> + ret = iadc_write(iadc, IADC_SEC_ACCESS, IADC_SEC_ACCESS_DATA);
> + if (ret < 0)
> + return ret;
> +
> + ret = iadc_write(iadc, IADC_MSB_OFFSET, msb);
> + if (ret < 0)
> + return ret;
> +
> + ret = iadc_write(iadc, IADC_SEC_ACCESS, IADC_SEC_ACCESS_DATA);
> + if (ret < 0)
> + return ret;
> +
> + return iadc_write(iadc, IADC_LSB_OFFSET, lsb);
> +}
> +
> +static int iadc_version_check(struct iadc_chip *iadc)
> +{
> + u8 revision, type, subtype;
> + int ret;
> +
> + ret = iadc_read(iadc, IADC_PERPH_TYPE, &type);
> + if (ret < 0)
> + return ret;
> +
> + if (type < IADC_PERPH_TYPE_ADC) {
> + dev_err(iadc->dev, "%d is not ADC\n", type);
> + return -EINVAL;
> + }
> +
> + ret = iadc_read(iadc, IADC_PERPH_SUBTYPE, &subtype);
> + if (ret < 0)
> + return ret;
> +
> + if (subtype < IADC_PERPH_SUBTYPE_IADC) {
> + dev_err(iadc->dev, "%d is not IADC\n", subtype);
> + return -EINVAL;
> + }
> +
> + ret = iadc_read(iadc, IADC_REVISION2, &revision);
> + if (ret < 0)
> + return ret;
> +
> + if (revision < IADC_REVISION2_SUPPORTED_IADC) {
> + dev_err(iadc->dev, "revision %d not supported\n", revision);
> + return -EINVAL;
> + }
> +
> + return iadc_read(iadc, IADC_INT_TEST_VAL, &iadc->factory);
> +}
> +
> +static int iadc_rsense_read(struct iadc_chip *iadc, struct device_node *node)
> +{
> + unsigned int trim_val;
> + u8 rsense, const_rds;
> + int ret, negative;
> + u32 trim_type;
> +
> + ret = of_property_read_u32(node, "qcom,rsense", &iadc->rsense);
> + if (!ret) {
> + iadc->ext_sense = true;
> + return 0;
> + }
> +
> + ret = iadc_read(iadc, IADC_NOMINAL_RSENSE, &rsense);
> + if (ret < 0)
> + return ret;
> +
> + negative = 0;
> + if (rsense & IADC_NOMINAL_RSENSE_SIGN_MASK)
> + negative = 1;
I'm a little confused. The docs say that rsense is a resistor value in
ohms (u32). Why does bit 7 allow encode other information?
> +
> + rsense &= ~IADC_NOMINAL_RSENSE_SIGN_MASK;
> +
> + iadc->rsense = IADC_INTERNAL_RSENSE_OHMS;
> + if (negative)
> + iadc->rsense -= rsense * IADC_RSENSE_OHMS_PER_BIT;
> + else
> + iadc->rsense += rsense * IADC_RSENSE_OHMS_PER_BIT;
> +
> + if (rsense < IADC_TRIM2_FULLSCALE)
> + return 0;
> + /*
> + * Trim register is "saturated", check for specific trim value
> + * based on manufacturer and RDS constant
> + */
> + ret = of_property_read_u32(node, "qcom,rds-trim", &trim_type);
> + if (ret)
> + return 0;
> +
> + ret = regmap_read(iadc->regmap, iadc->trim_rds, &trim_val);
> + if (ret < 0)
> + return ret;
> +
> + const_rds = trim_val & IADC_TRIM_CNST_RDS_MASK;
> +
> + dev_dbg(iadc->dev, "factory %d trim type %d rsense %d const %d\n",
> + iadc->factory, trim_type, rsense, const_rds);
> +
> + switch (trim_type) {
> + case 0:
> + if (const_rds == 2)
> + iadc->rsense = IADC_RSENSE_DEFAULT_VALUE;
So this is overwriting rsense if properties are obeyed. Would it not
make sense to do this before using the rsense value above (if these
constraints are not met?)
> + break;
> + case 1:
> + if (const_rds >= 2) {
> + iadc->rsense = IADC_RSENSE_DEFAULT_VALUE;
> + } else if (const_rds < 2) {
> + if (iadc->factory == IADC_FACTORY_GF)
> + iadc->rsense = IADC_RSENSE_DEFAULT_GF;
> + else if (iadc->factory == IADC_FACTORY_SMIC)
> + iadc->rsense = IADC_RSENSE_DEFAULT_SMIC;
> + }
> + break;
> + case 2:
> + if (const_rds > 0 && const_rds <= 2)
> + iadc->rsense = IADC_RSENSE_DEFAULT_VALUE;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static int iadc_probe(struct platform_device *pdev)
> +{
> + struct device_node *node = pdev->dev.of_node;
> + struct device *dev = &pdev->dev;
> + struct iio_chan_spec *iio_chan;
> + struct iio_dev *indio_dev;
> + struct iadc_chip *iadc;
> + struct resource *res;
> + struct regmap *regmap;
> + int ret, irq_eoc;
> +
> + regmap = dev_get_regmap(dev->parent, NULL);
> + if (!regmap)
> + return -ENODEV;
> +
> + indio_dev = devm_iio_device_alloc(dev, sizeof(*iadc));
> + if (!indio_dev)
> + return -ENOMEM;
Spinning the order of the regmap get and iio_device_alloc would perhaps
give a cleaner result as you could then fill iadc->regmap directly...
(marginal!)
> +
> + iadc = iio_priv(indio_dev);
> + iadc->dev = dev;
> + iadc->regmap = regmap;
> + init_completion(&iadc->complete);
> + mutex_init(&iadc->lock);
> +
> + platform_set_drvdata(pdev, iadc);
> +
> + res = platform_get_resource(pdev, IORESOURCE_REG, 0);
> + if (!res)
> + return -ENODEV;
> +
> + iadc->base = res->start;
> +
> + res = platform_get_resource(pdev, IORESOURCE_REG, 1);
> + if (!res)
> + return -ENODEV;
> +
> + iadc->trim_rds = res->start;
> +
> + 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, "%s sense resistor %d Ohm\n", iadc->ext_sense ?
> + "external" : "internal", iadc->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_trim_offset(iadc);
> + if (ret < 0) {
> + dev_err(dev, "failed trim offset calibration\n");
> + return ret;
> + }
> +
This stuff is basically constant configuration data, except that you
have two choices. Just have two static const struct iio_chan entries
outside here and pick between them based on ext_sense.
Also, why give them different channel numbers? Looks like it is just
to distinguish them in driver. If so, use address instead.
e.g.
static const struct iio_chan_spec iadc_channel_ext_rsense = {
.type = IIO_CURRENT,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
.address = 1,
.datasheet_name = "EXTERNAL_RSENSE",
};
static const struct iio_chan_spec iadc_channel_int_rsense = {
.type = IIO_CURRENT,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
.address = 0,
.datasheet_name = "INTERNAL_RSENSE",
};
No need to have a copy in iadc then...
The only time dynamic allocation of iio_chan_spec structures
makes sense is when there are lots of combinations and the
static const approach becomes too unweildy.
> + iio_chan = &iadc->iio_chan;
> + iio_chan->type = IIO_CURRENT;
> + iio_chan->indexed = 1;
> + iio_chan->info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED);
> + iio_chan->scan_type.sign = 's';
> + iio_chan->scan_type.realbits = 16;
> + iio_chan->scan_type.storagebits = 16;
> +
> + if (iadc->ext_sense) {
> + iio_chan->channel = 1;
> + iio_chan->datasheet_name = "EXTERNAL_RSENSE";
> + } else {
> + iio_chan->channel = 0;
> + iio_chan->datasheet_name = "INTERNAL_RSENSE";
> + }
> +
> + 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 = iio_chan;
> + indio_dev->num_channels = 1;
> +
> + 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 = "spmi-iadc",
> + .of_match_table = iadc_match_table,
> + },
> + .probe = iadc_probe,
> +};
> +module_platform_driver(iadc_driver);
> +
> +MODULE_ALIAS("platform:spmi-iadc");
> +MODULE_DESCRIPTION("Qualcomm SPMI PMIC current ADC driver");
> +MODULE_LICENSE("GPL v2");
>
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