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Message-ID: <54612A0D.7020308@gmx.de>
Date: Mon, 10 Nov 2014 22:11:41 +0100
From: Hartmut Knaack <knaack.h@....de>
To: "Ivan T. Ivanov" <iivanov@...sol.com>,
Jonathan Cameron <jic23@...nel.org>,
Lars-Peter Clausen <lars@...afoo.de>,
Peter Meerwald <pmeerw@...erw.net>
CC: Stanimir Varbanov <svarbanov@...sol.com>,
Angelo Compagnucci <angelo.compagnucci@...il.com>,
Grant Likely <grant.likely@...aro.org>,
linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org,
devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v4 2/2] iio: vadc: Qualcomm SPMI PMIC voltage ADC driver
Ivan T. Ivanov schrieb am 03.11.2014 16:24:
> From: Stanimir Varbanov <svarbanov@...sol.com>
>
> The voltage ADC is peripheral of Qualcomm SPMI PMIC chips. It has
> 15 bits resolution and register space inside PMIC accessible across
> SPMI bus.
>
> The vadc driver registers itself through IIO interface.
Reviewing again, I got the feeling that due to the complexity of adc reads (writing to register to start conversion, waiting a decent time for the conversion to complete, reading the result), it would be beneficial to use a mutex in vadc_read_raw or its depending functions.
Also, I would want to double-check that the CPU in this type of chips is little endian.
Besides that, a few minor issues inline.
>
> Signed-off-by: Stanimir Varbanov <svarbanov@...sol.com>
> Signed-off-by: Ivan T. Ivanov <iivanov@...sol.com>
> ---
> drivers/iio/adc/Kconfig | 14 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/qcom-spmi-vadc.c | 1015 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 1030 insertions(+)
> create mode 100644 drivers/iio/adc/qcom-spmi-vadc.c
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 88bdc8f..af6e10b 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_VADC
> + tristate "Qualcomm SPMI PMIC voltage ADC"
> + depends on SPMI
> + select REGMAP_SPMI
> + help
> + This is the IIO Voltage ADC driver for Qualcomm QPNP VADC Chip.
> +
> + The driver supports multiple channels read. The VADC is a 15-bit
> + sigma-delta ADC. Some of the channels are internally used for
> + calibration.
> +
> + To compile this driver as a module, choose M here: the module will
> + be called qcom-spmi-vadc.
> +
> 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..479b457 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-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
> obj-$(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-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c
> new file mode 100644
> index 0000000..6e6881c
> --- /dev/null
> +++ b/drivers/iio/adc/qcom-spmi-vadc.c
> @@ -0,0 +1,1015 @@
> +/*
> + * 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/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/log2.h>
> +
> +#include <dt-bindings/iio/qcom,spmi-vadc.h>
> +
> +/* VADC register and bit definitions */
> +#define VADC_REVISION2 0x1
> +#define VADC_REVISION2_SUPPORTED_VADC 1
> +
> +#define VADC_PERPH_TYPE 0x4
> +#define VADC_PERPH_TYPE_ADC 8
> +
> +#define VADC_PERPH_SUBTYPE 0x5
> +#define VADC_PERPH_SUBTYPE_VADC 1
> +
> +#define VADC_STATUS1 0x8
> +#define VADC_STATUS1_OP_MODE 4
> +#define VADC_STATUS1_REQ_STS BIT(1)
> +#define VADC_STATUS1_EOC BIT(0)
> +#define VADC_STATUS1_REQ_STS_EOC_MASK 0x3
> +
> +#define VADC_MODE_CTL 0x40
> +#define VADC_OP_MODE_SHIFT 3
> +#define VADC_OP_MODE_NORMAL 0
> +#define VADC_AMUX_TRIM_EN BIT(1)
> +#define VADC_ADC_TRIM_EN BIT(0)
> +
> +#define VADC_EN_CTL1 0x46
> +#define VADC_EN_CTL1_SET BIT(7)
> +
> +#define VADC_ADC_CH_SEL_CTL 0x48
> +
> +#define VADC_ADC_DIG_PARAM 0x50
> +#define VADC_ADC_DIG_DEC_RATIO_SEL_SHIFT 2
> +
> +#define VADC_HW_SETTLE_DELAY 0x51
> +
> +#define VADC_CONV_REQ 0x52
> +#define VADC_CONV_REQ_SET BIT(7)
> +
> +#define VADC_FAST_AVG_CTL 0x5a
> +#define VADC_FAST_AVG_EN 0x5b
> +#define VADC_FAST_AVG_EN_SET BIT(7)
> +
> +#define VADC_ACCESS 0xd0
> +#define VADC_ACCESS_DATA 0xa5
> +
> +#define VADC_PERH_RESET_CTL3 0xda
> +#define VADC_FOLLOW_WARM_RB BIT(2)
> +
> +#define VADC_DATA 0x60 /* 16 bits */
> +
> +#define VADC_CONV_TIME_MIN_US 2000
> +#define VADC_CONV_TIME_MAX_US 2100
> +
> +/* Min ADC code represents 0V */
> +#define VADC_MIN_ADC_CODE 0x6000
> +/* Max ADC code represents full-scale range of 1.8V */
> +#define VADC_MAX_ADC_CODE 0xa800
> +
> +#define VADC_ABSOLUTE_RANGE_UV 625000
> +#define VADC_RATIOMETRIC_RANGE_UV 1800000
> +
> +#define VADC_DEF_PRESCALING 0 /* 1:1 */
> +#define VADC_DEF_DECIMATION 0 /* 512 */
> +#define VADC_DEF_HW_SETTLE_TIME 0 /* 0 us */
> +#define VADC_DEF_AVG_SAMPLES 0 /* 1 sample */
> +#define VADC_DEF_CALIB_TYPE VADC_CALIB_ABSOLUTE
> +
> +#define VADC_DECIMATION_MIN 512
> +#define VADC_DECIMATION_MAX 4096
> +
> +#define VADC_HW_SETTLE_DELAY_MAX 10000
> +#define VADC_AVG_SAMPLES_MAX 512
> +
> +#define KELVINMIL_CELSIUSMIL 273150
> +
> +#define VADC_CHAN_MIN VADC_USBIN
> +#define VADC_CHAN_MAX VADC_LR_MUX3_BUF_PU1_PU2_XO_THERM
> +
> +/*
> + * VADC_CALIB_ABSOLUTE: uses the 625mV and 1.25V as reference channels.
> + * VADC_CALIB_RATIOMETRIC: uses the reference voltage (1.8V) and GND for
> + * calibration.
> + */
> +enum vadc_calibration {
> + VADC_CALIB_ABSOLUTE = 0,
> + VADC_CALIB_RATIOMETRIC
> +};
> +
> +/**
> + * struct vadc_linear_graph - Represent ADC characteristics.
> + * @dy: numerator slope to calculate the gain.
> + * @dx: denominator slope to calculate the gain.
> + * @vref: A/D word of the voltage reference used for the channel.
> + * @gnd: A/D word of the ground reference used for the channel.
> + *
> + * Each ADC device has different offset and gain parameters which are
> + * computed to calibrate the device.
> + */
> +struct vadc_linear_graph {
> + s32 dy;
> + s32 dx;
> + s32 vref;
> + s32 gnd;
> +};
> +
> +/**
> + * struct vadc_prescale_ratio - Represent scaling ratio for ADC input.
> + * @num: the inverse numerator of the gain applied to the input channel.
> + * @den: the inverse denominator of the gain applied to the input channel.
> + */
> +struct vadc_prescale_ratio {
> + u32 num;
> + u32 den;
> +};
> +
> +/**
> + * struct vadc_channel_prop - VADC channel property.
> + * @channel: channel number, refer to the channel list.
> + * @calibration: calibration type.
> + * @decimation: sampling rate supported for the channel.
> + * @prescale: channel scaling performed on the input signal.
> + * @hw_settle_time: the time between AMUX being configured and the
> + * start of conversion.
> + * @avg_samples: ability to provide single result from the ADC
> + * that is an average of multiple measurements.
> + */
> +struct vadc_channel_prop {
> + unsigned int channel;
> + enum vadc_calibration calibration;
> + unsigned int decimation;
> + unsigned int prescale;
> + unsigned int hw_settle_time;
> + unsigned int avg_samples;
> +};
> +
> +/**
> + * struct vadc_priv - VADC private structure.
> + * @regmap: pointer to struct regmap.
> + * @dev: pointer to struct device.
> + * @base: base address for the ADC peripheral.
> + * @nchannels: number of VADC channels.
> + * @chan_props: array of VADC channel properties.
> + * @iio_chans: array of IIO channels specification.
> + * @are_ref_measured: are reference points measured.
> + * @poll_eoc: use polling instead of interrupt.
> + * @complete: VADC result notification after interrupt is received.
> + * @graph: store parameters for calibration.
> + */
> +struct vadc_priv {
> + struct regmap *regmap;
> + struct device *dev;
> + u16 base;
> + unsigned int nchannels;
> + struct vadc_channel_prop *chan_props;
> + struct iio_chan_spec *iio_chans;
> + bool are_ref_measured;
> + bool poll_eoc;
> + struct completion complete;
> + struct vadc_linear_graph graph[2];
> +};
> +
> +static const struct vadc_prescale_ratio vadc_prescale_ratios[] = {
> + {.num = 1, .den = 1},
> + {.num = 1, .den = 3},
> + {.num = 1, .den = 4},
> + {.num = 1, .den = 6},
> + {.num = 1, .den = 20},
> + {.num = 1, .den = 8},
> + {.num = 10, .den = 81},
> + {.num = 1, .den = 10}
> +};
> +
> +static int vadc_read(struct vadc_priv *vadc, u16 offset, u8 *data)
> +{
> + return regmap_bulk_read(vadc->regmap, vadc->base + offset, data, 1);
> +}
> +
> +static int vadc_write(struct vadc_priv *vadc, u16 offset, u8 data)
> +{
> + return regmap_write(vadc->regmap, vadc->base + offset, data);
> +}
> +
> +static int vadc_reset(struct vadc_priv *vadc)
> +{
> + u8 data;
> + int ret;
> +
> + ret = vadc_write(vadc, VADC_ACCESS, VADC_ACCESS_DATA);
> + if (ret)
> + return ret;
> +
> + ret = vadc_read(vadc, VADC_PERH_RESET_CTL3, &data);
> + if (ret)
> + return ret;
> +
> + ret = vadc_write(vadc, VADC_ACCESS, VADC_ACCESS_DATA);
> + if (ret)
> + return ret;
> +
> + data |= VADC_FOLLOW_WARM_RB;
> +
> + return vadc_write(vadc, VADC_PERH_RESET_CTL3, data);
> +}
> +
> +static int vadc_set_state(struct vadc_priv *vadc, bool state)
> +{
> + return vadc_write(vadc, VADC_EN_CTL1, state ? VADC_EN_CTL1_SET : 0);
> +}
> +
> +static void vadc_show_status(struct vadc_priv *vadc)
> +{
> + u8 mode, sta1, chan, dig, en, req;
> + int ret;
> +
> + ret = vadc_read(vadc, VADC_MODE_CTL, &mode);
> + if (ret)
> + return;
> +
> + ret = vadc_read(vadc, VADC_ADC_DIG_PARAM, &dig);
> + if (ret)
> + return;
> +
> + ret = vadc_read(vadc, VADC_ADC_CH_SEL_CTL, &chan);
> + if (ret)
> + return;
> +
> + ret = vadc_read(vadc, VADC_CONV_REQ, &req);
> + if (ret)
> + return;
> +
> + ret = vadc_read(vadc, VADC_STATUS1, &sta1);
> + if (ret)
> + return;
> +
> + ret = vadc_read(vadc, VADC_EN_CTL1, &en);
> + if (ret)
> + return;
> +
> + dev_err(vadc->dev,
> + "mode:%02x en:%02x chan:%02x dig:%02x req:%02x sta1:%02x\n",
> + mode, en, chan, dig, req, sta1);
> +}
> +
> +static int vadc_configure(struct vadc_priv *vadc,
> + struct vadc_channel_prop *prop)
> +{
> + u8 decimation, mode_ctrl;
> + int ret;
> +
> + /* Mode selection */
> + mode_ctrl = (VADC_OP_MODE_NORMAL << VADC_OP_MODE_SHIFT) |
> + VADC_ADC_TRIM_EN | VADC_AMUX_TRIM_EN;
> + ret = vadc_write(vadc, VADC_MODE_CTL, mode_ctrl);
> + if (ret)
> + return ret;
> +
> + /* Channel selection */
> + ret = vadc_write(vadc, VADC_ADC_CH_SEL_CTL, prop->channel);
> + if (ret)
> + return ret;
> +
> + /* Digital parameter setup */
> + decimation = prop->decimation << VADC_ADC_DIG_DEC_RATIO_SEL_SHIFT;
> + ret = vadc_write(vadc, VADC_ADC_DIG_PARAM, decimation);
> + if (ret)
> + return ret;
> +
> + /* HW settle time delay */
> + ret = vadc_write(vadc, VADC_HW_SETTLE_DELAY, prop->hw_settle_time);
> + if (ret)
> + return ret;
> +
> + ret = vadc_write(vadc, VADC_FAST_AVG_CTL, prop->avg_samples);
> + if (ret)
> + return ret;
> +
> + if (prop->avg_samples)
> + ret = vadc_write(vadc, VADC_FAST_AVG_EN, VADC_FAST_AVG_EN_SET);
> + else
> + ret = vadc_write(vadc, VADC_FAST_AVG_EN, 0);
> +
> + return ret;
> +}
> +
> +static int vadc_poll_wait_eoc(struct vadc_priv *vadc, unsigned int interval_us)
> +{
> + unsigned int count, retry;
> + u8 sta1;
> + int ret;
> +
> + retry = interval_us / VADC_CONV_TIME_MIN_US;
> +
> + for (count = 0; count < retry; count++) {
> + ret = vadc_read(vadc, VADC_STATUS1, &sta1);
> + if (ret)
> + return ret;
> +
> + sta1 &= VADC_STATUS1_REQ_STS_EOC_MASK;
> + if (sta1 == VADC_STATUS1_EOC)
> + return 0;
> +
> + usleep_range(VADC_CONV_TIME_MIN_US, VADC_CONV_TIME_MAX_US);
> + }
> +
> + vadc_show_status(vadc);
> +
> + return -ETIMEDOUT;
> +}
> +
> +static int vadc_read_result(struct vadc_priv *vadc, u16 *data)
> +{
> + int ret;
> +
> + ret = regmap_bulk_read(vadc->regmap, vadc->base + VADC_DATA, data, 2);
> + if (ret)
> + return ret;
> +
> + *data = clamp_t(u16, *data, VADC_MIN_ADC_CODE, VADC_MAX_ADC_CODE);
> + return 0;
> +}
> +
> +static struct vadc_channel_prop *vadc_get_channel(struct vadc_priv *vadc,
> + unsigned int num)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < vadc->nchannels; i++)
> + if (vadc->chan_props[i].channel == num)
> + return &vadc->chan_props[i];
> +
> + dev_dbg(vadc->dev, "no such channel %02x\n", num);
> +
> + return NULL;
> +}
> +
> +static int vadc_do_conversion(struct vadc_priv *vadc,
> + struct vadc_channel_prop *prop, u16 *data)
> +{
> + unsigned int timeout;
> + int ret;
> +
> + ret = vadc_configure(vadc, prop);
> + if (ret)
> + return ret;
> +
> + if (!vadc->poll_eoc)
> + reinit_completion(&vadc->complete);
> +
> + ret = vadc_set_state(vadc, true);
> + if (ret)
> + return ret;
> +
> + ret = vadc_write(vadc, VADC_CONV_REQ, VADC_CONV_REQ_SET);
> + if (ret)
> + goto err_disable;
> +
> + timeout = BIT(prop->avg_samples) * VADC_CONV_TIME_MIN_US * 2;
> +
> + if (vadc->poll_eoc) {
> + ret = vadc_poll_wait_eoc(vadc, timeout);
> + } else {
> + ret = wait_for_completion_timeout(&vadc->complete, timeout);
> + if (!ret) {
> + ret = -ETIMEDOUT;
> + goto err_disable;
> + }
> +
> + /* Double check conversion status */
> + ret = vadc_poll_wait_eoc(vadc, VADC_CONV_TIME_MIN_US);
> + if (ret)
> + goto err_disable;
> + }
> +
> + ret = vadc_read_result(vadc, data);
> +
> +err_disable:
> + vadc_set_state(vadc, false);
> + if (ret)
> + dev_err(vadc->dev, "conversion failed\n");
> +
> + return ret;
> +}
> +
> +static int vadc_measure_ref_points(struct vadc_priv *vadc)
> +{
> + struct vadc_channel_prop *prop;
> + u16 read_1, read_2;
> + int ret;
> +
> + vadc->graph[VADC_CALIB_RATIOMETRIC].dx = VADC_RATIOMETRIC_RANGE_UV;
> + vadc->graph[VADC_CALIB_ABSOLUTE].dx = VADC_ABSOLUTE_RANGE_UV;
> +
> + prop = vadc_get_channel(vadc, VADC_REF_1250MV);
> + ret = vadc_do_conversion(vadc, prop, &read_1);
> + if (ret)
> + goto err;
> +
> + /* Try with buffered 625mV channel first */
> + prop = vadc_get_channel(vadc, VADC_SPARE1);
> + if (!prop)
> + prop = vadc_get_channel(vadc, VADC_REF_625MV);
> +
> + ret = vadc_do_conversion(vadc, prop, &read_2);
> + if (ret)
> + goto err;
> +
> + if (read_1 == read_2) {
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + vadc->graph[VADC_CALIB_ABSOLUTE].dy = read_1 - read_2;
> + vadc->graph[VADC_CALIB_ABSOLUTE].vref = read_1;
> + vadc->graph[VADC_CALIB_ABSOLUTE].gnd = read_2;
> +
> + /* Ratiometric calibration */
> + prop = vadc_get_channel(vadc, VADC_VDD_VADC);
> + ret = vadc_do_conversion(vadc, prop, &read_1);
> + if (ret)
> + goto err;
> +
> + prop = vadc_get_channel(vadc, VADC_GND_REF);
> + ret = vadc_do_conversion(vadc, prop, &read_2);
> + if (ret)
> + goto err;
> +
> + if (read_1 == read_2) {
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + vadc->graph[VADC_CALIB_RATIOMETRIC].dy = read_1 - read_2;
> + vadc->graph[VADC_CALIB_RATIOMETRIC].vref = read_1;
> + vadc->graph[VADC_CALIB_RATIOMETRIC].gnd = read_2;
> +err:
> + if (ret)
> + dev_err(vadc->dev, "measure reference points failed\n");
> +
> + return ret;
> +}
> +
> +static s32 vadc_calibrate(struct vadc_priv *vadc,
> + const struct vadc_channel_prop *prop, u16 adc_code)
> +{
> + const struct vadc_prescale_ratio *prescale;
> + s32 voltage;
> +
> + voltage = adc_code - vadc->graph[prop->calibration].gnd;
> + voltage *= vadc->graph[prop->calibration].dx;
> + voltage = voltage / vadc->graph[prop->calibration].dy;
> +
> + if (prop->calibration == VADC_CALIB_ABSOLUTE)
> + voltage += vadc->graph[prop->calibration].dx;
> +
> + if (voltage < 0)
> + voltage = 0;
> +
> + prescale = &vadc_prescale_ratios[prop->prescale];
> +
> + voltage = voltage * prescale->den;
> +
> + return voltage / prescale->num;
> +}
> +
> +static int vadc_decimation_from_dt(u32 value)
> +{
> + if (!is_power_of_2(value) || value < VADC_DECIMATION_MIN ||
> + value > VADC_DECIMATION_MAX)
> + return -EINVAL;
> +
> + return __ffs64(value / VADC_DECIMATION_MIN);
> +}
> +
> +static int vadc_prescaling_from_dt(u32 num, u32 den)
> +{
> + unsigned int pre;
> +
> + for (pre = 0; pre < ARRAY_SIZE(vadc_prescale_ratios); pre++)
> + if (vadc_prescale_ratios[pre].num == num &&
> + vadc_prescale_ratios[pre].den == den)
> + break;
> +
> + if (pre == ARRAY_SIZE(vadc_prescale_ratios))
> + return -EINVAL;
> +
> + return pre;
> +}
> +
> +static int vadc_hw_settle_time_from_dt(u32 value)
> +{
> + if ((value <= 1000 && value % 100) || (value > 1000 && value % 2000))
> + return -EINVAL;
> +
> + if (value <= 1000)
> + value /= 100;
> + else
> + value = value / 2000 + 10;
> +
> + return value;
> +}
> +
> +static int vadc_avg_samples_from_dt(u32 value)
> +{
> + if (!is_power_of_2(value) || value > VADC_AVG_SAMPLES_MAX)
> + return -EINVAL;
> +
> + return __ffs64(value);
> +}
> +
> +static int vadc_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int *val, int *val2,
> + long mask)
> +{
> + struct vadc_priv *vadc = iio_priv(indio_dev);
> + struct vadc_channel_prop *prop;
> + u16 adc_code;
> + int ret;
> +
> + if (!vadc->are_ref_measured) {
> + ret = vadc_measure_ref_points(vadc);
> + if (ret)
> + return ret;
> +
> + vadc->are_ref_measured = true;
> + }
> +
> + if (mask == IIO_CHAN_INFO_PROCESSED || mask == IIO_CHAN_INFO_RAW) {
> + prop = &vadc->chan_props[chan->address];
> + ret = vadc_do_conversion(vadc, prop, &adc_code);
> + if (ret)
> + return ret;
> +
> + *val = vadc_calibrate(vadc, prop, adc_code);
> + }
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_PROCESSED:
> + if (chan->type != IIO_TEMP && chan->channel != VADC_DIE_TEMP)
> + return -EINVAL;
> +
> + /* 2mV/K, return milli Celsius */
> + *val /= 2;
> + *val -= KELVINMIL_CELSIUSMIL;
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_RAW:
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + *val = 0;
> + *val2 = 1000;
> + return IIO_VAL_INT_PLUS_MICRO;
> + default:
> + break;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int vadc_of_xlate(struct iio_dev *indio_dev,
> + const struct of_phandle_args *iiospec)
> +{
> + struct vadc_priv *vadc = iio_priv(indio_dev);
> + unsigned int i;
> +
> + for (i = 0; i < vadc->nchannels; i++)
> + if (vadc->iio_chans[i].channel == iiospec->args[0])
> + return i;
> +
> + return -EINVAL;
> +}
> +
> +static const struct iio_info vadc_info = {
> + .read_raw = vadc_read_raw,
> + .of_xlate = vadc_of_xlate,
> + .driver_module = THIS_MODULE,
> +};
> +
> +struct vadc_channels {
> + const char *datasheet_name;
> + unsigned int prescale_index;
> + enum iio_chan_type type;
> + long info_mask;
> +};
> +
> +#define VADC_CHAN(_dname, _type, _mask, _pre) \
> + [VADC_##_dname] = { \
> + .datasheet_name = __stringify(_dname), \
> + .prescale_index = _pre, \
> + .type = _type, \
> + .info_mask = _mask \
> + }, \
> +
> +#define VADC_CHAN_TEMP(_dname, _pre) \
> + VADC_CHAN(_dname, IIO_TEMP, BIT(IIO_CHAN_INFO_PROCESSED), _pre) \
> +
> +#define VADC_CHAN_VOLT(_dname, _pre) \
> + VADC_CHAN(_dname, IIO_VOLTAGE, \
> + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), \
> + _pre) \
> +
> +/*
> + * The array represents all possible ADC channels found in the supported PMICs.
> + * Every index in the array is equal to the channel number per datasheet. The
> + * gaps in the array should be treated as reserved channels.
> + */
> +static const struct vadc_channels vadc_chans[] = {
> + VADC_CHAN_VOLT(USBIN, 4)
> + VADC_CHAN_VOLT(DCIN, 4)
> + VADC_CHAN_VOLT(VCHG_SNS, 3)
> + VADC_CHAN_VOLT(SPARE1_03, 1)
> + VADC_CHAN_VOLT(USB_ID_MV, 1)
> + VADC_CHAN_VOLT(VCOIN, 1)
> + VADC_CHAN_VOLT(VBAT_SNS, 1)
> + VADC_CHAN_VOLT(VSYS, 1)
> + VADC_CHAN_TEMP(DIE_TEMP, 0)
> + VADC_CHAN_VOLT(REF_625MV, 0)
> + VADC_CHAN_VOLT(REF_1250MV, 0)
> + VADC_CHAN_VOLT(CHG_TEMP, 0)
> + VADC_CHAN_VOLT(SPARE1, 0)
> + VADC_CHAN_VOLT(SPARE2, 0)
> + VADC_CHAN_VOLT(GND_REF, 0)
> + VADC_CHAN_VOLT(VDD_VADC, 0)
> +
> + VADC_CHAN_VOLT(P_MUX1_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX2_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX3_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX4_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX5_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX6_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX7_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX8_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX9_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX10_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX11_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX12_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX13_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX14_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX15_1_1, 0)
> + VADC_CHAN_VOLT(P_MUX16_1_1, 0)
> +
> + VADC_CHAN_VOLT(P_MUX1_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX2_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX3_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX4_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX5_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX6_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX7_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX8_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX9_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX10_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX11_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX12_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX13_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX14_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX15_1_3, 1)
> + VADC_CHAN_VOLT(P_MUX16_1_3, 1)
> +
> + VADC_CHAN_VOLT(LR_MUX1_BAT_THERM, 0)
> + VADC_CHAN_VOLT(LR_MUX2_BAT_ID, 0)
> + VADC_CHAN_VOLT(LR_MUX3_XO_THERM, 0)
> + VADC_CHAN_VOLT(LR_MUX4_AMUX_THM1, 0)
> + VADC_CHAN_VOLT(LR_MUX5_AMUX_THM2, 0)
> + VADC_CHAN_VOLT(LR_MUX6_AMUX_THM3, 0)
> + VADC_CHAN_VOLT(LR_MUX7_HW_ID, 0)
> + VADC_CHAN_VOLT(LR_MUX8_AMUX_THM4, 0)
> + VADC_CHAN_VOLT(LR_MUX9_AMUX_THM5, 0)
> + VADC_CHAN_VOLT(LR_MUX10_USB_ID, 0)
> + VADC_CHAN_VOLT(AMUX_PU1, 0)
> + VADC_CHAN_VOLT(AMUX_PU2, 0)
> + VADC_CHAN_VOLT(LR_MUX3_BUF_XO_THERM, 0)
> +
> + VADC_CHAN_VOLT(LR_MUX1_PU1_BAT_THERM, 0)
> + VADC_CHAN_VOLT(LR_MUX2_PU1_BAT_ID, 0)
> + VADC_CHAN_VOLT(LR_MUX3_PU1_XO_THERM, 0)
> + VADC_CHAN_VOLT(LR_MUX4_PU1_AMUX_THM1, 0)
> + VADC_CHAN_VOLT(LR_MUX5_PU1_AMUX_THM2, 0)
> + VADC_CHAN_VOLT(LR_MUX6_PU1_AMUX_THM3, 0)
> + VADC_CHAN_VOLT(LR_MUX7_PU1_AMUX_HW_ID, 0)
> + VADC_CHAN_VOLT(LR_MUX8_PU1_AMUX_THM4, 0)
> + VADC_CHAN_VOLT(LR_MUX9_PU1_AMUX_THM5, 0)
> + VADC_CHAN_VOLT(LR_MUX10_PU1_AMUX_USB_ID, 0)
> + VADC_CHAN_VOLT(LR_MUX3_BUF_PU1_XO_THERM, 0)
> +
> + VADC_CHAN_VOLT(LR_MUX1_PU2_BAT_THERM, 0)
> + VADC_CHAN_VOLT(LR_MUX2_PU2_BAT_ID, 0)
> + VADC_CHAN_VOLT(LR_MUX3_PU2_XO_THERM, 0)
> + VADC_CHAN_VOLT(LR_MUX4_PU2_AMUX_THM1, 0)
> + VADC_CHAN_VOLT(LR_MUX5_PU2_AMUX_THM2, 0)
> + VADC_CHAN_VOLT(LR_MUX6_PU2_AMUX_THM3, 0)
> + VADC_CHAN_VOLT(LR_MUX7_PU2_AMUX_HW_ID, 0)
> + VADC_CHAN_VOLT(LR_MUX8_PU2_AMUX_THM4, 0)
> + VADC_CHAN_VOLT(LR_MUX9_PU2_AMUX_THM5, 0)
> + VADC_CHAN_VOLT(LR_MUX10_PU2_AMUX_USB_ID, 0)
> + VADC_CHAN_VOLT(LR_MUX3_BUF_PU2_XO_THERM, 0)
> +
> + VADC_CHAN_VOLT(LR_MUX1_PU1_PU2_BAT_THERM, 0)
> + VADC_CHAN_VOLT(LR_MUX2_PU1_PU2_BAT_ID, 0)
> + VADC_CHAN_VOLT(LR_MUX3_PU1_PU2_XO_THERM, 0)
> + VADC_CHAN_VOLT(LR_MUX4_PU1_PU2_AMUX_THM1, 0)
> + VADC_CHAN_VOLT(LR_MUX5_PU1_PU2_AMUX_THM2, 0)
> + VADC_CHAN_VOLT(LR_MUX6_PU1_PU2_AMUX_THM3, 0)
> + VADC_CHAN_VOLT(LR_MUX7_PU1_PU2_AMUX_HW_ID, 0)
> + VADC_CHAN_VOLT(LR_MUX8_PU1_PU2_AMUX_THM4, 0)
> + VADC_CHAN_VOLT(LR_MUX9_PU1_PU2_AMUX_THM5, 0)
> + VADC_CHAN_VOLT(LR_MUX10_PU1_PU2_AMUX_USB_ID, 0)
> + VADC_CHAN_VOLT(LR_MUX3_BUF_PU1_PU2_XO_THERM, 0)
> +};
> +
> +static int vadc_get_dt_channel_data(struct device *dev,
> + struct vadc_channel_prop *prop,
> + struct device_node *node)
> +{
> + const char *name = node->name;
> + u32 chan, value, varr[2];
> + int ret;
> +
> + ret = of_property_read_u32(node, "reg", &chan);
> + if (ret) {
> + dev_err(dev, "invalid channel number %s\n", name);
> + return ret;
> + }
> +
> + if (chan > VADC_CHAN_MAX || chan < VADC_CHAN_MIN) {
> + dev_err(dev, "%s invalid channel number %d\n", name, chan);
> + return -EINVAL;
> + }
> +
> + /* the channel has DT description */
> + prop->channel = chan;
> +
> + ret = of_property_read_u32(node, "qcom,decimation", &value);
> + if (!ret) {
> + ret = vadc_decimation_from_dt(value);
> + if (ret < 0) {
> + dev_err(dev, "%02x invalid decimation %d\n",
> + chan, value);
> + return ret;
> + }
> + prop->decimation = ret;
> + } else {
> + prop->decimation = VADC_DEF_DECIMATION;
> + }
> +
> + ret = of_property_read_u32_array(node, "qcom,pre-scaling", varr, 2);
> + if (!ret) {
> + ret = vadc_prescaling_from_dt(varr[0], varr[1]);
> + if (ret < 0) {
> + dev_err(dev, "%02x invalid pre-scaling <%d %d>\n",
> + chan, varr[0], varr[1]);
> + return ret;
> + }
> + prop->prescale = ret;
> + } else {
> + prop->prescale = vadc_chans[prop->channel].prescale_index;
> + }
> +
> + ret = of_property_read_u32(node, "qcom,hw-settle-time", &value);
> + if (!ret) {
> + ret = vadc_hw_settle_time_from_dt(value);
> + if (ret < 0) {
> + dev_err(dev, "%02x invalid hw-settle-time %d us\n",
> + chan, value);
> + return ret;
> + }
> + prop->hw_settle_time = ret;
> + } else {
> + prop->hw_settle_time = VADC_DEF_HW_SETTLE_TIME;
> + }
> +
> + ret = of_property_read_u32(node, "qcom,avg-samples", &value);
> + if (!ret) {
> + ret = vadc_avg_samples_from_dt(value);
> + if (ret < 0) {
> + dev_err(dev, "%02x invalid avg-samples %d\n",
> + chan, value);
> + return ret;
> + }
> + prop->avg_samples = ret;
> + } else {
> + prop->avg_samples = VADC_DEF_AVG_SAMPLES;
> + }
> +
> + if (of_property_read_bool(node, "qcom,ratiometric"))
> + prop->calibration = VADC_CALIB_RATIOMETRIC;
> + else
> + prop->calibration = VADC_CALIB_ABSOLUTE;
> +
> + dev_dbg(dev, "%02x name %s\n", chan, name);
> +
> + return 0;
> +}
> +
> +static int vadc_get_dt_data(struct vadc_priv *vadc, struct device_node *node)
> +{
> + const struct vadc_channels *vadc_chan;
> + struct iio_chan_spec *iio_chan;
> + struct vadc_channel_prop prop;
> + struct device_node *child;
> + unsigned int index = 0;
> + int ret;
> +
> + vadc->nchannels = of_get_available_child_count(node);
> + if (!vadc->nchannels)
> + return -EINVAL;
> +
> + vadc->iio_chans = devm_kcalloc(vadc->dev, vadc->nchannels,
> + sizeof(*vadc->iio_chans), GFP_KERNEL);
> + if (!vadc->iio_chans)
> + return -ENOMEM;
> +
> + vadc->chan_props = devm_kcalloc(vadc->dev, vadc->nchannels,
> + sizeof(*vadc->chan_props), GFP_KERNEL);
> + if (!vadc->chan_props)
> + return -ENOMEM;
> +
> + iio_chan = vadc->iio_chans;
> +
> + for_each_available_child_of_node(node, child) {
> + ret = vadc_get_dt_channel_data(vadc->dev, &prop, child);
> + if (ret)
> + return ret;
> +
> + vadc->chan_props[index] = prop;
> +
> + vadc_chan = &vadc_chans[prop.channel];
> +
> + iio_chan->channel = prop.channel;
> + iio_chan->datasheet_name = vadc_chan->datasheet_name;
> + iio_chan->info_mask_separate = vadc_chan->info_mask;
> + iio_chan->type = vadc_chan->type;
> + iio_chan->indexed = 1;
> + iio_chan->address = index++;
> +
> + iio_chan++;
> + }
> +
> + /* These channels are mandatory, they are used as reference points */
> + if (!vadc_get_channel(vadc, VADC_REF_1250MV)) {
> + dev_err(vadc->dev, "Please define 1.25V channel\n");
> + return -ENODEV;
> + }
> +
> + if (!vadc_get_channel(vadc, VADC_REF_625MV)) {
> + dev_err(vadc->dev, "Please define 0.625V channel\n");
> + return -ENODEV;
> + }
> +
> + if (!vadc_get_channel(vadc, VADC_VDD_VADC)) {
> + dev_err(vadc->dev, "Please define VDD channel\n");
> + return -ENODEV;
> + }
> +
> + if (!vadc_get_channel(vadc, VADC_GND_REF)) {
> + dev_err(vadc->dev, "Please define GND channel\n");
> + return -ENODEV;
> + }
> +
> + return 0;
> +}
> +
> +static irqreturn_t vadc_isr(int irq, void *dev_id)
> +{
> + struct vadc_priv *vadc = dev_id;
> +
> + complete(&vadc->complete);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int vadc_check_revision(struct vadc_priv *vadc)
> +{
> + u8 val;
> + int ret;
> +
> + ret = vadc_read(vadc, VADC_PERPH_TYPE, &val);
> + if (ret)
> + return ret;
> +
> + if (val < VADC_PERPH_TYPE_ADC) {
> + dev_err(vadc->dev, "%d is not ADC\n", val);
> + return -ENODEV;
> + }
> +
> + ret = vadc_read(vadc, VADC_PERPH_SUBTYPE, &val);
> + if (ret)
> + return ret;
> +
> + if (val < VADC_PERPH_SUBTYPE_VADC) {
> + dev_err(vadc->dev, "%d is not VADC\n", val);
> + return -ENODEV;
> + }
> +
> + ret = vadc_read(vadc, VADC_REVISION2, &val);
> + if (ret)
> + return ret;
> +
> + if (val < VADC_REVISION2_SUPPORTED_VADC) {
> + dev_err(vadc->dev, "revision %d not supported\n", val);
> + return -ENODEV;
> + }
> +
> + return 0;
> +}
> +
> +static int vadc_probe(struct platform_device *pdev)
> +{
> + struct device_node *node = pdev->dev.of_node;
> + struct device *dev = &pdev->dev;
> + struct iio_dev *indio_dev;
> + struct vadc_priv *vadc;
> + struct regmap *regmap;
> + int ret, irq_eoc;
> + u32 res;
Since vadc->base is u16, shouldn't res be u16 as well? Also think about naming it reg, as this is the property name in DT.
> +
> + regmap = dev_get_regmap(dev->parent, NULL);
> + if (!regmap)
> + return -ENODEV;
> +
> + ret = of_property_read_u32(node, "reg", &res);
For u16, there would be of_property_read_u16().
> + if (ret < 0)
> + return -ENODEV;
Just return ret here?
> +
> + indio_dev = devm_iio_device_alloc(dev, sizeof(*vadc));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + vadc = iio_priv(indio_dev);
> + vadc->regmap = regmap;
> + vadc->dev = dev;
> + vadc->base = res;
> + vadc->are_ref_measured = false;
> + init_completion(&vadc->complete);
> +
> + ret = vadc_check_revision(vadc);
> + if (ret)
> + return ret;
> +
> + ret = vadc_get_dt_data(vadc, node);
> + if (ret)
> + return ret;
> +
> + irq_eoc = platform_get_irq(pdev, 0);
> + if (irq_eoc < 0) {
> + if (irq_eoc == -EPROBE_DEFER || irq_eoc == -EINVAL)
> + return irq_eoc;
> + vadc->poll_eoc = true;
> + } else {
> + ret = devm_request_irq(dev, irq_eoc, vadc_isr, 0,
> + "spmi-vadc", vadc);
> + if (ret)
> + return ret;
> + }
> +
> + ret = vadc_reset(vadc);
> + if (ret) {
> + dev_err(dev, "reset failed\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 = &vadc_info;
> + indio_dev->channels = vadc->iio_chans;
> + indio_dev->num_channels = vadc->nchannels;
> +
> + return devm_iio_device_register(dev, indio_dev);
> +}
> +
> +static const struct of_device_id vadc_match_table[] = {
> + { .compatible = "qcom,spmi-vadc" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, vadc_match_table);
> +
> +static struct platform_driver vadc_driver = {
> + .driver = {
> + .name = "qcom-spmi-vadc",
> + .of_match_table = vadc_match_table,
> + },
> + .probe = vadc_probe,
> +};
> +module_platform_driver(vadc_driver);
> +
> +MODULE_ALIAS("platform:qcom-spmi-vadc");
> +MODULE_DESCRIPTION("Qualcomm SPMI PMIC voltage ADC driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Stanimir Varbanov <svarbanov@...sol.com>");
> +MODULE_AUTHOR("Ivan T. Ivanov <iivanov@...sol.com>");
>
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