394 lines
10 KiB
C
394 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2025, Duje Mihanović <duje@dujemihanovic.xyz>
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*/
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#include <linux/bits.h>
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#include <linux/bug.h>
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/i2c.h>
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#include <linux/math.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/pm_runtime.h>
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#include <linux/regmap.h>
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#include <linux/types.h>
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#include <linux/units.h>
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#include <asm/byteorder.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/types.h>
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#include <linux/mfd/88pm886.h>
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struct pm886_gpadc {
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struct regmap *map;
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};
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enum pm886_gpadc_channel {
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VSC_CHAN,
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VCHG_PWR_CHAN,
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VCF_OUT_CHAN,
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VBAT_CHAN,
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VBAT_SLP_CHAN,
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VBUS_CHAN,
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GPADC0_CHAN,
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GPADC1_CHAN,
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GPADC2_CHAN,
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GPADC3_CHAN,
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GND_DET1_CHAN,
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GND_DET2_CHAN,
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MIC_DET_CHAN,
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TINT_CHAN,
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};
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static const int pm886_gpadc_regs[] = {
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[VSC_CHAN] = PM886_REG_GPADC_VSC,
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[VCHG_PWR_CHAN] = PM886_REG_GPADC_VCHG_PWR,
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[VCF_OUT_CHAN] = PM886_REG_GPADC_VCF_OUT,
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[VBAT_CHAN] = PM886_REG_GPADC_VBAT,
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[VBAT_SLP_CHAN] = PM886_REG_GPADC_VBAT_SLP,
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[VBUS_CHAN] = PM886_REG_GPADC_VBUS,
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[GPADC0_CHAN] = PM886_REG_GPADC_GPADC0,
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[GPADC1_CHAN] = PM886_REG_GPADC_GPADC1,
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[GPADC2_CHAN] = PM886_REG_GPADC_GPADC2,
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[GPADC3_CHAN] = PM886_REG_GPADC_GPADC3,
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[GND_DET1_CHAN] = PM886_REG_GPADC_GND_DET1,
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[GND_DET2_CHAN] = PM886_REG_GPADC_GND_DET2,
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[MIC_DET_CHAN] = PM886_REG_GPADC_MIC_DET,
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[TINT_CHAN] = PM886_REG_GPADC_TINT,
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};
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#define ADC_CHANNEL_VOLTAGE(index, lsb, name) \
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{ \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.channel = index, \
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.address = lsb, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
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BIT(IIO_CHAN_INFO_SCALE), \
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.datasheet_name = name, \
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}
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#define ADC_CHANNEL_RESISTANCE(index, lsb, name) \
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{ \
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.type = IIO_RESISTANCE, \
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.indexed = 1, \
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.channel = index, \
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.address = lsb, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
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.datasheet_name = name, \
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}
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#define ADC_CHANNEL_TEMPERATURE(index, lsb, name) \
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{ \
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.type = IIO_TEMP, \
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.indexed = 1, \
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.channel = index, \
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.address = lsb, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
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BIT(IIO_CHAN_INFO_SCALE) | \
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BIT(IIO_CHAN_INFO_OFFSET), \
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.datasheet_name = name, \
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}
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static const struct iio_chan_spec pm886_gpadc_channels[] = {
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ADC_CHANNEL_VOLTAGE(VSC_CHAN, 1367, "vsc"),
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ADC_CHANNEL_VOLTAGE(VCHG_PWR_CHAN, 1709, "vchg_pwr"),
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ADC_CHANNEL_VOLTAGE(VCF_OUT_CHAN, 1367, "vcf_out"),
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ADC_CHANNEL_VOLTAGE(VBAT_CHAN, 1367, "vbat"),
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ADC_CHANNEL_VOLTAGE(VBAT_SLP_CHAN, 1367, "vbat_slp"),
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ADC_CHANNEL_VOLTAGE(VBUS_CHAN, 1709, "vbus"),
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ADC_CHANNEL_RESISTANCE(GPADC0_CHAN, 342, "gpadc0"),
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ADC_CHANNEL_RESISTANCE(GPADC1_CHAN, 342, "gpadc1"),
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ADC_CHANNEL_RESISTANCE(GPADC2_CHAN, 342, "gpadc2"),
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ADC_CHANNEL_RESISTANCE(GPADC3_CHAN, 342, "gpadc3"),
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ADC_CHANNEL_VOLTAGE(GND_DET1_CHAN, 342, "gnddet1"),
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ADC_CHANNEL_VOLTAGE(GND_DET2_CHAN, 342, "gnddet2"),
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ADC_CHANNEL_VOLTAGE(MIC_DET_CHAN, 1367, "mic_det"),
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ADC_CHANNEL_TEMPERATURE(TINT_CHAN, 104, "tint"),
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};
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static const struct regmap_config pm886_gpadc_regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.max_register = PM886_GPADC_MAX_REGISTER,
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};
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static int gpadc_get_raw(struct iio_dev *iio, enum pm886_gpadc_channel chan)
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{
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struct pm886_gpadc *gpadc = iio_priv(iio);
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__be16 buf;
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int ret;
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ret = regmap_bulk_read(gpadc->map, pm886_gpadc_regs[chan], &buf, sizeof(buf));
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if (ret)
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return ret;
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return be16_to_cpu(buf) >> 4;
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}
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static int
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gpadc_set_bias(struct pm886_gpadc *gpadc, enum pm886_gpadc_channel chan, bool on)
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{
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unsigned int gpadc_num = chan - GPADC0_CHAN;
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unsigned int bits = BIT(gpadc_num + 4) | BIT(gpadc_num);
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return regmap_assign_bits(gpadc->map, PM886_REG_GPADC_CONFIG(0x14), bits, on);
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}
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static int
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gpadc_find_bias_current(struct iio_dev *iio, struct iio_chan_spec const *chan,
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unsigned int *raw_uV, unsigned int *raw_uA)
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{
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struct pm886_gpadc *gpadc = iio_priv(iio);
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unsigned int gpadc_num = chan->channel - GPADC0_CHAN;
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unsigned int reg = PM886_REG_GPADC_CONFIG(0xb + gpadc_num);
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unsigned long lsb = chan->address;
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int ret;
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for (unsigned int i = 0; i < PM886_GPADC_BIAS_LEVELS; i++) {
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ret = regmap_update_bits(gpadc->map, reg, GENMASK(3, 0), i);
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if (ret)
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return ret;
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/* Wait for the new bias level to apply. */
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fsleep(5 * USEC_PER_MSEC);
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*raw_uA = PM886_GPADC_INDEX_TO_BIAS_uA(i);
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*raw_uV = gpadc_get_raw(iio, chan->channel) * lsb;
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/*
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* Vendor kernel errors out above 1.25 V, but testing shows
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* that the resistance of the battery detection channel (GPADC2
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* on coreprimevelte) reaches about 1.4 MΩ when the battery is
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* removed, which can't be measured with such a low upper
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* limit. Therefore, to be able to detect the battery without
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* ugly externs as used in the vendor fuel gauge driver,
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* increase this limit a bit.
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*/
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if (WARN_ON(*raw_uV > 1500 * (MICRO / MILLI)))
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return -EIO;
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/*
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* Vendor kernel errors out under 300 mV, but for the same
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* reason as above (except the channel hovers around 3.5 kΩ
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* with battery present) reduce this limit.
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*/
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if (*raw_uV < 200 * (MICRO / MILLI)) {
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dev_dbg(&iio->dev, "bad bias for chan %d: %d uA @ %d uV\n",
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chan->channel, *raw_uA, *raw_uV);
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continue;
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}
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dev_dbg(&iio->dev, "good bias for chan %d: %d uA @ %d uV\n",
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chan->channel, *raw_uA, *raw_uV);
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return 0;
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}
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dev_err(&iio->dev, "failed to find good bias for chan %d\n", chan->channel);
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return -EINVAL;
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}
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static int
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gpadc_get_resistance_ohm(struct iio_dev *iio, struct iio_chan_spec const *chan)
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{
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struct pm886_gpadc *gpadc = iio_priv(iio);
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unsigned int raw_uV, raw_uA;
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int ret;
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ret = gpadc_set_bias(gpadc, chan->channel, true);
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if (ret)
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goto out;
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ret = gpadc_find_bias_current(iio, chan, &raw_uV, &raw_uA);
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if (ret)
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goto out;
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ret = DIV_ROUND_CLOSEST(raw_uV, raw_uA);
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out:
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gpadc_set_bias(gpadc, chan->channel, false);
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return ret;
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}
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static int
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__pm886_gpadc_read_raw(struct iio_dev *iio, struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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unsigned long lsb = chan->address;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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*val = gpadc_get_raw(iio, chan->channel);
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if (*val < 0)
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return *val;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*val = lsb;
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if (chan->type == IIO_VOLTAGE) {
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*val2 = MILLI;
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return IIO_VAL_FRACTIONAL;
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} else {
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return IIO_VAL_INT;
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}
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case IIO_CHAN_INFO_OFFSET:
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/* Raw value is 104 millikelvin/LSB, convert it to 104 millicelsius/LSB */
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*val = ABSOLUTE_ZERO_MILLICELSIUS;
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*val2 = lsb;
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return IIO_VAL_FRACTIONAL;
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case IIO_CHAN_INFO_PROCESSED:
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*val = gpadc_get_resistance_ohm(iio, chan);
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if (*val < 0)
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return *val;
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return IIO_VAL_INT;
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default:
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return -EINVAL;
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}
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}
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static int pm886_gpadc_read_raw(struct iio_dev *iio, struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct device *dev = iio->dev.parent;
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int ret;
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ret = pm_runtime_resume_and_get(dev);
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if (ret)
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return ret;
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ret = __pm886_gpadc_read_raw(iio, chan, val, val2, mask);
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pm_runtime_put_autosuspend(dev);
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return ret;
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}
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static int pm886_gpadc_hw_enable(struct regmap *map)
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{
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const u8 config[] = {
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PM886_GPADC_CONFIG1_EN_ALL,
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PM886_GPADC_CONFIG2_EN_ALL,
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PM886_GPADC_GND_DET2_EN,
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};
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int ret;
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/* Enable the ADC block. */
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ret = regmap_set_bits(map, PM886_REG_GPADC_CONFIG(0x6), BIT(0));
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if (ret)
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return ret;
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/* Enable all channels. */
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return regmap_bulk_write(map, PM886_REG_GPADC_CONFIG(0x1), config, ARRAY_SIZE(config));
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}
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static int pm886_gpadc_hw_disable(struct regmap *map)
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{
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return regmap_clear_bits(map, PM886_REG_GPADC_CONFIG(0x6), BIT(0));
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}
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static const struct iio_info pm886_gpadc_iio_info = {
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.read_raw = pm886_gpadc_read_raw,
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};
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static int pm886_gpadc_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct pm886_chip *chip = dev_get_drvdata(dev->parent);
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struct i2c_client *client = chip->client;
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struct pm886_gpadc *gpadc;
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struct i2c_client *page;
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struct iio_dev *iio;
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int ret;
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iio = devm_iio_device_alloc(dev, sizeof(*gpadc));
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if (!iio)
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return -ENOMEM;
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gpadc = iio_priv(iio);
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dev_set_drvdata(dev, iio);
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page = devm_i2c_new_dummy_device(dev, client->adapter,
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client->addr + PM886_PAGE_OFFSET_GPADC);
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if (IS_ERR(page))
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return dev_err_probe(dev, PTR_ERR(page), "Failed to initialize GPADC page\n");
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gpadc->map = devm_regmap_init_i2c(page, &pm886_gpadc_regmap_config);
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if (IS_ERR(gpadc->map))
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return dev_err_probe(dev, PTR_ERR(gpadc->map),
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"Failed to initialize GPADC regmap\n");
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iio->name = "88pm886-gpadc";
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iio->modes = INDIO_DIRECT_MODE;
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iio->info = &pm886_gpadc_iio_info;
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iio->channels = pm886_gpadc_channels;
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iio->num_channels = ARRAY_SIZE(pm886_gpadc_channels);
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device_set_node(&iio->dev, dev_fwnode(dev->parent));
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ret = devm_pm_runtime_enable(dev);
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if (ret)
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return dev_err_probe(dev, ret, "Failed to enable runtime PM\n");
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pm_runtime_set_autosuspend_delay(dev, 50);
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pm_runtime_use_autosuspend(dev);
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ret = devm_iio_device_register(dev, iio);
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if (ret)
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return dev_err_probe(dev, ret, "Failed to register ADC\n");
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return 0;
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}
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static int pm886_gpadc_runtime_resume(struct device *dev)
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{
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struct iio_dev *iio = dev_get_drvdata(dev);
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struct pm886_gpadc *gpadc = iio_priv(iio);
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return pm886_gpadc_hw_enable(gpadc->map);
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}
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static int pm886_gpadc_runtime_suspend(struct device *dev)
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{
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struct iio_dev *iio = dev_get_drvdata(dev);
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struct pm886_gpadc *gpadc = iio_priv(iio);
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return pm886_gpadc_hw_disable(gpadc->map);
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}
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static DEFINE_RUNTIME_DEV_PM_OPS(pm886_gpadc_pm_ops,
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pm886_gpadc_runtime_suspend,
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pm886_gpadc_runtime_resume, NULL);
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static const struct platform_device_id pm886_gpadc_id[] = {
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{ "88pm886-gpadc" },
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{ }
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};
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MODULE_DEVICE_TABLE(platform, pm886_gpadc_id);
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static struct platform_driver pm886_gpadc_driver = {
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.driver = {
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.name = "88pm886-gpadc",
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.pm = pm_ptr(&pm886_gpadc_pm_ops),
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},
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.probe = pm886_gpadc_probe,
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.id_table = pm886_gpadc_id,
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};
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module_platform_driver(pm886_gpadc_driver);
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MODULE_AUTHOR("Duje Mihanović <duje@dujemihanovic.xyz>");
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MODULE_DESCRIPTION("Marvell 88PM886 GPADC driver");
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MODULE_LICENSE("GPL");
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