linux/drivers/iio/adc/qcom-spmi-iadc.c

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/*
* 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.
* @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)
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,
usecs_to_jiffies(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_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
* 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 */
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@mm-sol.com>");