diff options
Diffstat (limited to 'drivers/iio/adc/intel_dc_ti_adc.c')
| -rw-r--r-- | drivers/iio/adc/intel_dc_ti_adc.c | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/drivers/iio/adc/intel_dc_ti_adc.c b/drivers/iio/adc/intel_dc_ti_adc.c new file mode 100644 index 000000000000..0fe34f1c338e --- /dev/null +++ b/drivers/iio/adc/intel_dc_ti_adc.c @@ -0,0 +1,328 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Intel Dollar Cove TI PMIC GPADC Driver + * + * Copyright (C) 2014 Intel Corporation (Ramakrishna Pallala <ramakrishna.pallala@intel.com>) + * Copyright (C) 2024 - 2025 Hans de Goede <hansg@kernel.org> + */ + +#include <linux/bits.h> +#include <linux/bitfield.h> +#include <linux/bitops.h> +#include <linux/cleanup.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/interrupt.h> +#include <linux/mfd/intel_soc_pmic.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/wait.h> + +#include <linux/iio/driver.h> +#include <linux/iio/iio.h> +#include <linux/iio/machine.h> + +#define DC_TI_ADC_CNTL_REG 0x50 +#define DC_TI_ADC_START BIT(0) +#define DC_TI_ADC_CH_SEL GENMASK(2, 1) +#define DC_TI_ADC_EN BIT(5) +#define DC_TI_ADC_EN_EXT_BPTH_BIAS BIT(6) + +#define DC_TI_VBAT_ZSE_GE_REG 0x53 +#define DC_TI_VBAT_GE GENMASK(3, 0) +#define DC_TI_VBAT_ZSE GENMASK(7, 4) + +/* VBAT GE gain correction is in 0.0015 increments, ZSE is in 1.0 increments */ +#define DC_TI_VBAT_GE_STEP 15 +#define DC_TI_VBAT_GE_DIV 10000 + +#define DC_TI_ADC_DATA_REG_CH(x) (0x54 + 2 * (x)) + +enum dc_ti_adc_id { + DC_TI_ADC_VBAT, + DC_TI_ADC_PMICTEMP, + DC_TI_ADC_BATTEMP, + DC_TI_ADC_SYSTEMP0, +}; + +struct dc_ti_adc_info { + struct mutex lock; /* Protects against concurrent accesses to the ADC */ + wait_queue_head_t wait; + struct device *dev; + struct regmap *regmap; + int vbat_zse; + int vbat_ge; + bool conversion_done; +}; + +static const struct iio_chan_spec dc_ti_adc_channels[] = { + { + .indexed = 1, + .type = IIO_VOLTAGE, + .channel = DC_TI_ADC_VBAT, + .address = DC_TI_ADC_DATA_REG_CH(0), + .datasheet_name = "CH0", + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE) | + BIT(IIO_CHAN_INFO_PROCESSED), + }, { + .indexed = 1, + .type = IIO_TEMP, + .channel = DC_TI_ADC_PMICTEMP, + .address = DC_TI_ADC_DATA_REG_CH(1), + .datasheet_name = "CH1", + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + }, { + .indexed = 1, + .type = IIO_TEMP, + .channel = DC_TI_ADC_BATTEMP, + .address = DC_TI_ADC_DATA_REG_CH(2), + .datasheet_name = "CH2", + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + }, { + .indexed = 1, + .type = IIO_TEMP, + .channel = DC_TI_ADC_SYSTEMP0, + .address = DC_TI_ADC_DATA_REG_CH(3), + .datasheet_name = "CH3", + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + } +}; + +static struct iio_map dc_ti_adc_default_maps[] = { + IIO_MAP("CH0", "chtdc_ti_battery", "VBAT"), + IIO_MAP("CH1", "chtdc_ti_battery", "PMICTEMP"), + IIO_MAP("CH2", "chtdc_ti_battery", "BATTEMP"), + IIO_MAP("CH3", "chtdc_ti_battery", "SYSTEMP0"), + { } +}; + +static irqreturn_t dc_ti_adc_isr(int irq, void *data) +{ + struct dc_ti_adc_info *info = data; + + info->conversion_done = true; + wake_up(&info->wait); + return IRQ_HANDLED; +} + +static int dc_ti_adc_scale(struct dc_ti_adc_info *info, + struct iio_chan_spec const *chan, + int *val, int *val2) +{ + if (chan->channel != DC_TI_ADC_VBAT) + return -EINVAL; + + /* Vbat ADC scale is 4.6875 mV / unit */ + *val = 4; + *val2 = 687500; + + return IIO_VAL_INT_PLUS_MICRO; +} + +static int dc_ti_adc_raw_to_processed(struct dc_ti_adc_info *info, + struct iio_chan_spec const *chan, + int raw, int *val, int *val2) +{ + if (chan->channel != DC_TI_ADC_VBAT) + return -EINVAL; + + /* Apply calibration */ + raw -= info->vbat_zse; + raw = raw * (DC_TI_VBAT_GE_DIV - info->vbat_ge * DC_TI_VBAT_GE_STEP) / + DC_TI_VBAT_GE_DIV; + /* Vbat ADC scale is 4.6875 mV / unit */ + raw *= 46875; + + /* raw is now in 10000 units / mV, convert to milli + milli/1e6 */ + *val = raw / 10000; + *val2 = (raw % 10000) * 100; + + return IIO_VAL_INT_PLUS_MICRO; +} + +static int dc_ti_adc_sample(struct dc_ti_adc_info *info, + struct iio_chan_spec const *chan, int *val) +{ + int ret, ch = chan->channel; + __be16 buf; + + info->conversion_done = false; + + /* + * As per TI (PMIC Vendor), the ADC enable and ADC start commands should + * not be sent together. Hence send the commands separately. + */ + ret = regmap_set_bits(info->regmap, DC_TI_ADC_CNTL_REG, DC_TI_ADC_EN); + if (ret) + return ret; + + ret = regmap_update_bits(info->regmap, DC_TI_ADC_CNTL_REG, + DC_TI_ADC_CH_SEL, + FIELD_PREP(DC_TI_ADC_CH_SEL, ch)); + if (ret) + return ret; + + /* + * As per PMIC Vendor, a minimum of 50 ųs delay is required between ADC + * Enable and ADC START commands. This is also recommended by Intel + * Hardware team after the timing analysis of GPADC signals. Since the + * I2C Write transaction to set the channel number also imparts 25 ųs + * delay, we need to wait for another 25 ųs before issuing ADC START. + */ + fsleep(25); + + ret = regmap_set_bits(info->regmap, DC_TI_ADC_CNTL_REG, + DC_TI_ADC_START); + if (ret) + return ret; + + /* TI (PMIC Vendor) recommends 5 s timeout for conversion */ + ret = wait_event_timeout(info->wait, info->conversion_done, 5 * HZ); + if (ret == 0) { + ret = -ETIMEDOUT; + goto disable_adc; + } + + ret = regmap_bulk_read(info->regmap, chan->address, &buf, sizeof(buf)); + if (ret) + goto disable_adc; + + /* The ADC values are 10 bits wide */ + *val = be16_to_cpu(buf) & GENMASK(9, 0); + +disable_adc: + regmap_clear_bits(info->regmap, DC_TI_ADC_CNTL_REG, + DC_TI_ADC_START | DC_TI_ADC_EN); + return ret; +} + +static int dc_ti_adc_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct dc_ti_adc_info *info = iio_priv(indio_dev); + int ret; + + if (mask == IIO_CHAN_INFO_SCALE) + return dc_ti_adc_scale(info, chan, val, val2); + + guard(mutex)(&info->lock); + + /* + * If channel BPTHERM has been selected, first enable the BPTHERM BIAS + * which provides the VREF Voltage reference to convert BPTHERM Input + * voltage to temperature. + */ + if (chan->channel == DC_TI_ADC_BATTEMP) { + ret = regmap_set_bits(info->regmap, DC_TI_ADC_CNTL_REG, + DC_TI_ADC_EN_EXT_BPTH_BIAS); + if (ret) + return ret; + /* + * As per PMIC Vendor specifications, BPTHERM BIAS should be + * enabled 35 ms before ADC_EN command. + */ + msleep(35); + } + + ret = dc_ti_adc_sample(info, chan, val); + + if (chan->channel == DC_TI_ADC_BATTEMP) + regmap_clear_bits(info->regmap, DC_TI_ADC_CNTL_REG, + DC_TI_ADC_EN_EXT_BPTH_BIAS); + + if (ret) + return ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + return IIO_VAL_INT; + case IIO_CHAN_INFO_PROCESSED: + return dc_ti_adc_raw_to_processed(info, chan, *val, val, val2); + } + + return -EINVAL; +} + +static const struct iio_info dc_ti_adc_iio_info = { + .read_raw = dc_ti_adc_read_raw, +}; + +static int dc_ti_adc_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct intel_soc_pmic *pmic = dev_get_drvdata(dev->parent); + struct dc_ti_adc_info *info; + struct iio_dev *indio_dev; + unsigned int val; + int irq, ret; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*info)); + if (!indio_dev) + return -ENOMEM; + + info = iio_priv(indio_dev); + + ret = devm_mutex_init(dev, &info->lock); + if (ret) + return ret; + + init_waitqueue_head(&info->wait); + + info->dev = dev; + info->regmap = pmic->regmap; + + indio_dev->name = "dc_ti_adc"; + indio_dev->channels = dc_ti_adc_channels; + indio_dev->num_channels = ARRAY_SIZE(dc_ti_adc_channels); + indio_dev->info = &dc_ti_adc_iio_info; + indio_dev->modes = INDIO_DIRECT_MODE; + + ret = regmap_read(info->regmap, DC_TI_VBAT_ZSE_GE_REG, &val); + if (ret) + return ret; + + info->vbat_zse = sign_extend32(FIELD_GET(DC_TI_VBAT_ZSE, val), 3); + info->vbat_ge = sign_extend32(FIELD_GET(DC_TI_VBAT_GE, val), 3); + + dev_dbg(dev, "vbat-zse %d vbat-ge %d\n", info->vbat_zse, info->vbat_ge); + + ret = devm_iio_map_array_register(dev, indio_dev, dc_ti_adc_default_maps); + if (ret) + return ret; + + ret = devm_request_threaded_irq(dev, irq, NULL, dc_ti_adc_isr, + IRQF_ONESHOT, indio_dev->name, info); + if (ret) + return ret; + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct platform_device_id dc_ti_adc_ids[] = { + { .name = "chtdc_ti_adc" }, + { } +}; +MODULE_DEVICE_TABLE(platform, dc_ti_adc_ids); + +static struct platform_driver dc_ti_adc_driver = { + .driver = { + .name = "dc_ti_adc", + }, + .probe = dc_ti_adc_probe, + .id_table = dc_ti_adc_ids, +}; +module_platform_driver(dc_ti_adc_driver); + +MODULE_AUTHOR("Ramakrishna Pallala (Intel)"); +MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>"); +MODULE_DESCRIPTION("Intel Dollar Cove (TI) GPADC Driver"); +MODULE_LICENSE("GPL"); |