--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * IIO driver for PAC1921 High-Side Power/Current Monitor
+ *
+ * Copyright (C) 2024 Matteo Martelli <matteomartelli3@gmail.com>
+ */
+
+#include <asm/unaligned.h>
+#include <linux/bitfield.h>
+#include <linux/i2c.h>
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/regmap.h>
+#include <linux/units.h>
+
+/* pac1921 registers */
+#define PAC1921_REG_GAIN_CFG 0x00
+#define PAC1921_REG_INT_CFG 0x01
+#define PAC1921_REG_CONTROL 0x02
+#define PAC1921_REG_VBUS 0x10
+#define PAC1921_REG_VSENSE 0x12
+#define PAC1921_REG_OVERFLOW_STS 0x1C
+#define PAC1921_REG_VPOWER 0x1D
+
+/* pac1921 gain configuration bits */
+#define PAC1921_GAIN_DI_GAIN_MASK GENMASK(5, 3)
+#define PAC1921_GAIN_DV_GAIN_MASK GENMASK(2, 0)
+
+/* pac1921 integration configuration bits */
+#define PAC1921_INT_CFG_SMPL_MASK GENMASK(7, 4)
+#define PAC1921_INT_CFG_VSFEN BIT(3)
+#define PAC1921_INT_CFG_VBFEN BIT(2)
+#define PAC1921_INT_CFG_RIOV BIT(1)
+#define PAC1921_INT_CFG_INTEN BIT(0)
+
+/* pac1921 control bits */
+#define PAC1921_CONTROL_MXSL_MASK GENMASK(7, 6)
+enum pac1921_mxsl {
+ PAC1921_MXSL_VPOWER_PIN = 0,
+ PAC1921_MXSL_VSENSE_FREE_RUN = 1,
+ PAC1921_MXSL_VBUS_FREE_RUN = 2,
+ PAC1921_MXSL_VPOWER_FREE_RUN = 3,
+};
+#define PAC1921_CONTROL_SLEEP BIT(2)
+
+/* pac1921 result registers mask and resolution */
+#define PAC1921_RES_MASK GENMASK(15, 6)
+#define PAC1921_RES_RESOLUTION 1023
+
+/* pac1921 overflow status bits */
+#define PAC1921_OVERFLOW_VSOV BIT(2)
+#define PAC1921_OVERFLOW_VBOV BIT(1)
+#define PAC1921_OVERFLOW_VPOV BIT(0)
+
+/* pac1921 constants */
+#define PAC1921_MAX_VSENSE_MV 100
+#define PAC1921_MAX_VBUS_V 32
+/* Time to first communication after power up (tINT_T) */
+#define PAC1921_POWERUP_TIME_MS 20
+/* Time from Sleep State to Start of Integration Period (tSLEEP_TO_INT) */
+#define PAC1921_SLEEP_TO_INT_TIME_US 86
+
+/* pac1921 defaults */
+#define PAC1921_DEFAULT_DV_GAIN 0 /* 2^(value): 1x gain (HW default) */
+#define PAC1921_DEFAULT_DI_GAIN 0 /* 2^(value): 1x gain (HW default) */
+#define PAC1921_DEFAULT_NUM_SAMPLES 0 /* 2^(value): 1 sample (HW default) */
+
+/*
+ * Pre-computed scale factors for BUS voltage
+ * format: IIO_VAL_INT_PLUS_NANO
+ * unit: mV
+ *
+ * Vbus scale (mV) = max_vbus (mV) / dv_gain / resolution
+ */
+static const int pac1921_vbus_scales[][2] = {
+ { 31, 280547409 }, /* dv_gain x1 */
+ { 15, 640273704 }, /* dv_gain x2 */
+ { 7, 820136852 }, /* dv_gain x4 */
+ { 3, 910068426 }, /* dv_gain x8 */
+ { 1, 955034213 }, /* dv_gain x16 */
+ { 0, 977517106 }, /* dv_gain x32 */
+};
+
+/*
+ * Pre-computed scales for SENSE voltage
+ * format: IIO_VAL_INT_PLUS_NANO
+ * unit: mV
+ *
+ * Vsense scale (mV) = max_vsense (mV) / di_gain / resolution
+ */
+static const int pac1921_vsense_scales[][2] = {
+ { 0, 97751710 }, /* di_gain x1 */
+ { 0, 48875855 }, /* di_gain x2 */
+ { 0, 24437927 }, /* di_gain x4 */
+ { 0, 12218963 }, /* di_gain x8 */
+ { 0, 6109481 }, /* di_gain x16 */
+ { 0, 3054740 }, /* di_gain x32 */
+ { 0, 1527370 }, /* di_gain x64 */
+ { 0, 763685 }, /* di_gain x128 */
+};
+
+/*
+ * Numbers of samples used to integrate measurements at the end of an
+ * integration period.
+ *
+ * Changing the number of samples affects the integration period: higher the
+ * number of samples, longer the integration period.
+ *
+ * These correspond to the oversampling ratios available exposed to userspace.
+ */
+static const int pac1921_int_num_samples[] = {
+ 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048
+};
+
+/*
+ * The integration period depends on the configuration of number of integration
+ * samples, measurement resolution and post filters. The following array
+ * contains integration periods, in microsecs unit, based on table 4-5 from
+ * datasheet considering power integration mode, 14-Bit resolution and post
+ * filters on. Each index corresponds to a specific number of samples from 1
+ * to 2048.
+ */
+static const unsigned int pac1921_int_periods_usecs[] = {
+ 2720, /* 1 sample */
+ 4050, /* 2 samples */
+ 6790, /* 4 samples */
+ 12200, /* 8 samples */
+ 23000, /* 16 samples */
+ 46000, /* 32 samples */
+ 92000, /* 64 samples */
+ 184000, /* 128 samples */
+ 368000, /* 256 samples */
+ 736000, /* 512 samples */
+ 1471000, /* 1024 samples */
+ 2941000 /* 2048 samples */
+};
+
+/* pac1921 regmap configuration */
+static const struct regmap_range pac1921_regmap_wr_ranges[] = {
+ regmap_reg_range(PAC1921_REG_GAIN_CFG, PAC1921_REG_CONTROL),
+};
+
+static const struct regmap_access_table pac1921_regmap_wr_table = {
+ .yes_ranges = pac1921_regmap_wr_ranges,
+ .n_yes_ranges = ARRAY_SIZE(pac1921_regmap_wr_ranges),
+};
+
+static const struct regmap_range pac1921_regmap_rd_ranges[] = {
+ regmap_reg_range(PAC1921_REG_GAIN_CFG, PAC1921_REG_CONTROL),
+ regmap_reg_range(PAC1921_REG_VBUS, PAC1921_REG_VPOWER + 1),
+};
+
+static const struct regmap_access_table pac1921_regmap_rd_table = {
+ .yes_ranges = pac1921_regmap_rd_ranges,
+ .n_yes_ranges = ARRAY_SIZE(pac1921_regmap_rd_ranges),
+};
+
+static const struct regmap_config pac1921_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .rd_table = &pac1921_regmap_rd_table,
+ .wr_table = &pac1921_regmap_wr_table,
+};
+
+enum pac1921_channels {
+ PAC1921_CHAN_VBUS = 0,
+ PAC1921_CHAN_VSENSE = 1,
+ PAC1921_CHAN_CURRENT = 2,
+ PAC1921_CHAN_POWER = 3,
+};
+#define PAC1921_NUM_MEAS_CHANS 4
+
+struct pac1921_priv {
+ struct i2c_client *client;
+ struct regmap *regmap;
+ struct regulator *vdd;
+ struct iio_info iio_info;
+
+ /*
+ * Synchronize access to private members, and ensure atomicity of
+ * consecutive regmap operations.
+ */
+ struct mutex lock;
+
+ u32 rshunt_uohm; /* uOhm */
+ u8 dv_gain;
+ u8 di_gain;
+ u8 n_samples;
+ u8 prev_ovf_flags;
+ u8 ovf_enabled_events;
+
+ bool first_integr_started;
+ bool first_integr_done;
+ unsigned long integr_started_time_jiffies;
+ unsigned int integr_period_usecs;
+
+ int current_scales[ARRAY_SIZE(pac1921_vsense_scales)][2];
+
+ struct {
+ u16 chan[PAC1921_NUM_MEAS_CHANS];
+ s64 timestamp __aligned(8);
+ } scan;
+};
+
+/*
+ * Check if first integration after configuration update has completed.
+ *
+ * Must be called with lock held.
+ */
+static bool pac1921_data_ready(struct pac1921_priv *priv)
+{
+ if (!priv->first_integr_started)
+ return false;
+
+ if (!priv->first_integr_done) {
+ unsigned long t_ready;
+
+ /*
+ * Data valid after the device entered into integration state,
+ * considering worst case where the device was in sleep state,
+ * and completed the first integration period.
+ */
+ t_ready = priv->integr_started_time_jiffies +
+ usecs_to_jiffies(PAC1921_SLEEP_TO_INT_TIME_US) +
+ usecs_to_jiffies(priv->integr_period_usecs);
+
+ if (time_before(jiffies, t_ready))
+ return false;
+
+ priv->first_integr_done = true;
+ }
+
+ return true;
+}
+
+static inline void pac1921_calc_scale(int dividend, int divisor, int *val,
+ int *val2)
+{
+ s64 tmp;
+
+ tmp = div_s64(dividend * (s64)NANO, divisor);
+ *val = (int)div_s64_rem(tmp, NANO, val2);
+}
+
+/*
+ * Fill the table of scale factors for current
+ * format: IIO_VAL_INT_PLUS_NANO
+ * unit: mA
+ *
+ * Vsense LSB (nV) = max_vsense (nV) * di_gain / resolution
+ * Current scale (mA) = Vsense LSB (nV) / shunt (uOhm)
+ *
+ * Must be called with held lock when updating after first initialization.
+ */
+static void pac1921_calc_current_scales(struct pac1921_priv *priv)
+{
+ for (unsigned int i = 0; i < ARRAY_SIZE(priv->current_scales); i++) {
+ int max = (PAC1921_MAX_VSENSE_MV * MICRO) >> i;
+ int vsense_lsb = DIV_ROUND_CLOSEST(max, PAC1921_RES_RESOLUTION);
+
+ pac1921_calc_scale(vsense_lsb, (int)priv->rshunt_uohm,
+ &priv->current_scales[i][0],
+ &priv->current_scales[i][1]);
+ }
+}
+
+/*
+ * Check if overflow occurred and if so, push the corresponding events.
+ *
+ * Must be called with lock held.
+ */
+static int pac1921_check_push_overflow(struct iio_dev *indio_dev, s64 timestamp)
+{
+ struct pac1921_priv *priv = iio_priv(indio_dev);
+ unsigned int flags;
+ int ret;
+
+ ret = regmap_read(priv->regmap, PAC1921_REG_OVERFLOW_STS, &flags);
+ if (ret)
+ return ret;
+
+ if (flags & PAC1921_OVERFLOW_VBOV &&
+ !(priv->prev_ovf_flags & PAC1921_OVERFLOW_VBOV) &&
+ priv->ovf_enabled_events & PAC1921_OVERFLOW_VBOV) {
+ iio_push_event(indio_dev,
+ IIO_UNMOD_EVENT_CODE(
+ IIO_VOLTAGE, PAC1921_CHAN_VBUS,
+ IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING),
+ timestamp);
+ }
+ if (flags & PAC1921_OVERFLOW_VSOV &&
+ !(priv->prev_ovf_flags & PAC1921_OVERFLOW_VSOV) &&
+ priv->ovf_enabled_events & PAC1921_OVERFLOW_VSOV) {
+ iio_push_event(indio_dev,
+ IIO_UNMOD_EVENT_CODE(
+ IIO_VOLTAGE, PAC1921_CHAN_VSENSE,
+ IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING),
+ timestamp);
+ iio_push_event(indio_dev,
+ IIO_UNMOD_EVENT_CODE(
+ IIO_CURRENT, PAC1921_CHAN_CURRENT,
+ IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING),
+ timestamp);
+ }
+ if (flags & PAC1921_OVERFLOW_VPOV &&
+ !(priv->prev_ovf_flags & PAC1921_OVERFLOW_VPOV) &&
+ priv->ovf_enabled_events & PAC1921_OVERFLOW_VPOV) {
+ iio_push_event(indio_dev,
+ IIO_UNMOD_EVENT_CODE(
+ IIO_POWER, PAC1921_CHAN_POWER,
+ IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING),
+ timestamp);
+ }
+
+ priv->prev_ovf_flags = (u8)flags;
+
+ return 0;
+}
+
+/*
+ * Read the value from a result register
+ *
+ * Result registers contain the most recent averaged values of Vbus, Vsense and
+ * Vpower. Each value is 10 bits wide and spread across two consecutive 8 bit
+ * registers, with 6 bit LSB zero padding.
+ */
+static int pac1921_read_res(struct pac1921_priv *priv, unsigned long reg,
+ u16 *val)
+{
+ int ret = regmap_bulk_read(priv->regmap, (unsigned int)reg, val,
+ sizeof(*val));
+ if (ret)
+ return ret;
+
+ *val = FIELD_GET(PAC1921_RES_MASK, get_unaligned_be16(val));
+
+ return 0;
+}
+
+static int pac1921_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ struct pac1921_priv *priv = iio_priv(indio_dev);
+
+ guard(mutex)(&priv->lock);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW: {
+ s64 ts;
+ u16 res_val;
+ int ret;
+
+ if (!pac1921_data_ready(priv))
+ return -EBUSY;
+
+ ts = iio_get_time_ns(indio_dev);
+
+ ret = pac1921_check_push_overflow(indio_dev, ts);
+ if (ret)
+ return ret;
+
+ ret = pac1921_read_res(priv, chan->address, &res_val);
+ if (ret)
+ return ret;
+
+ *val = (int)res_val;
+
+ return IIO_VAL_INT;
+ }
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->channel) {
+ case PAC1921_CHAN_VBUS:
+ *val = pac1921_vbus_scales[priv->dv_gain][0];
+ *val2 = pac1921_vbus_scales[priv->dv_gain][1];
+ return IIO_VAL_INT_PLUS_NANO;
+
+ case PAC1921_CHAN_VSENSE:
+ *val = pac1921_vsense_scales[priv->di_gain][0];
+ *val2 = pac1921_vsense_scales[priv->di_gain][1];
+ return IIO_VAL_INT_PLUS_NANO;
+
+ case PAC1921_CHAN_CURRENT:
+ *val = priv->current_scales[priv->di_gain][0];
+ *val2 = priv->current_scales[priv->di_gain][1];
+ return IIO_VAL_INT_PLUS_NANO;
+
+ case PAC1921_CHAN_POWER: {
+ /*
+ * Power scale factor in mW:
+ * Current scale (mA) * max_vbus (V) / dv_gain
+ */
+
+ /* Get current scale based on di_gain */
+ int *curr_scale = priv->current_scales[priv->di_gain];
+
+ /* Convert current_scale from INT_PLUS_NANO to INT */
+ s64 tmp = curr_scale[0] * (s64)NANO + curr_scale[1];
+
+ /* Multiply by max_vbus (V) / dv_gain */
+ tmp *= PAC1921_MAX_VBUS_V >> (int)priv->dv_gain;
+
+ /* Convert back to INT_PLUS_NANO */
+ *val = (int)div_s64_rem(tmp, NANO, val2);
+
+ return IIO_VAL_INT_PLUS_NANO;
+ }
+ default:
+ return -EINVAL;
+ }
+
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ *val = pac1921_int_num_samples[priv->n_samples];
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ /*
+ * The sampling frequency (Hz) is read-only and corresponds to
+ * how often the device provides integrated measurements into
+ * the result registers, thus it's 1/integration_period.
+ * The integration period depends on the number of integration
+ * samples, measurement resolution and post filters.
+ *
+ * 1/(integr_period_usecs/MICRO) = MICRO/integr_period_usecs
+ */
+ *val = MICRO;
+ *val2 = (int)priv->integr_period_usecs;
+ return IIO_VAL_FRACTIONAL;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int pac1921_read_avail(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ const int **vals, int *type, int *length,
+ long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ *type = IIO_VAL_INT;
+ *vals = pac1921_int_num_samples;
+ *length = ARRAY_SIZE(pac1921_int_num_samples);
+ return IIO_AVAIL_LIST;
+ default:
+ return -EINVAL;
+ }
+}
+
+/*
+ * Perform configuration update sequence: set the device into read state, then
+ * write the config register and set the device back into integration state.
+ * Also reset integration start time and mark first integration to be yet
+ * completed.
+ *
+ * Must be called with lock held.
+ */
+static int pac1921_update_cfg_reg(struct pac1921_priv *priv, unsigned int reg,
+ unsigned int mask, unsigned int val)
+{
+ /* Enter READ state before configuration */
+ int ret = regmap_update_bits(priv->regmap, PAC1921_REG_INT_CFG,
+ PAC1921_INT_CFG_INTEN, 0);
+ if (ret)
+ return ret;
+
+ /* Update configuration value */
+ ret = regmap_update_bits(priv->regmap, reg, mask, val);
+ if (ret)
+ return ret;
+
+ /* Re-enable integration */
+ ret = regmap_update_bits(priv->regmap, PAC1921_REG_INT_CFG,
+ PAC1921_INT_CFG_INTEN, PAC1921_INT_CFG_INTEN);
+ if (ret)
+ return ret;
+
+ /*
+ * Reset integration started time and mark this integration period as
+ * the first one so that new measurements will be considered as valid
+ * only at the end of this integration period.
+ */
+ priv->integr_started_time_jiffies = jiffies;
+ priv->first_integr_done = false;
+
+ return 0;
+}
+
+/*
+ * Retrieve the index of the given scale (represented by scale_val and
+ * scale_val2) from scales_tbl. The returned index (if found) is the log2 of
+ * the gain corresponding to the given scale.
+ *
+ * Must be called with lock held if the scales_tbl can change runtime (e.g. for
+ * the current scales table)
+ */
+static int pac1921_lookup_scale(const int (*const scales_tbl)[2], size_t size,
+ int scale_val, int scale_val2)
+{
+ for (unsigned int i = 0; i < size; i++)
+ if (scales_tbl[i][0] == scale_val &&
+ scales_tbl[i][1] == scale_val2)
+ return (int)i;
+
+ return -EINVAL;
+}
+
+/*
+ * Configure device with the given gain (only if changed)
+ *
+ * Must be called with lock held.
+ */
+static int pac1921_update_gain(struct pac1921_priv *priv, u8 *priv_val, u8 gain,
+ unsigned int mask)
+{
+ unsigned int reg_val;
+ int ret;
+
+ if (*priv_val == gain)
+ return 0;
+
+ reg_val = (gain << __ffs(mask)) & mask;
+ ret = pac1921_update_cfg_reg(priv, PAC1921_REG_GAIN_CFG, mask, reg_val);
+ if (ret)
+ return ret;
+
+ *priv_val = gain;
+
+ return 0;
+}
+
+/*
+ * Given a scale factor represented by scale_val and scale_val2 with format
+ * IIO_VAL_INT_PLUS_NANO, find the corresponding gain value and write it to the
+ * device.
+ *
+ * Must be called with lock held.
+ */
+static int pac1921_update_gain_from_scale(struct pac1921_priv *priv,
+ struct iio_chan_spec const *chan,
+ int scale_val, int scale_val2)
+{
+ int ret;
+
+ switch (chan->channel) {
+ case PAC1921_CHAN_VBUS:
+ ret = pac1921_lookup_scale(pac1921_vbus_scales,
+ ARRAY_SIZE(pac1921_vbus_scales),
+ scale_val, scale_val2);
+ if (ret < 0)
+ return ret;
+
+ return pac1921_update_gain(priv, &priv->dv_gain, (u8)ret,
+ PAC1921_GAIN_DV_GAIN_MASK);
+ case PAC1921_CHAN_VSENSE:
+ ret = pac1921_lookup_scale(pac1921_vsense_scales,
+ ARRAY_SIZE(pac1921_vsense_scales),
+ scale_val, scale_val2);
+ if (ret < 0)
+ return ret;
+
+ return pac1921_update_gain(priv, &priv->di_gain, (u8)ret,
+ PAC1921_GAIN_DI_GAIN_MASK);
+ case PAC1921_CHAN_CURRENT:
+ ret = pac1921_lookup_scale(priv->current_scales,
+ ARRAY_SIZE(priv->current_scales),
+ scale_val, scale_val2);
+ if (ret < 0)
+ return ret;
+
+ return pac1921_update_gain(priv, &priv->di_gain, (u8)ret,
+ PAC1921_GAIN_DI_GAIN_MASK);
+ default:
+ return -EINVAL;
+ }
+}
+
+/*
+ * Retrieve the index of the given number of samples from the constant table.
+ * The returned index (if found) is the log2 of the given num_samples.
+ */
+static int pac1921_lookup_int_num_samples(int num_samples)
+{
+ for (unsigned int i = 0; i < ARRAY_SIZE(pac1921_int_num_samples); i++)
+ if (pac1921_int_num_samples[i] == num_samples)
+ return (int)i;
+
+ return -EINVAL;
+}
+
+/*
+ * Update the device with the given number of integration samples.
+ *
+ * Must be called with lock held.
+ */
+static int pac1921_update_int_num_samples(struct pac1921_priv *priv,
+ int num_samples)
+{
+ unsigned int reg_val;
+ u8 n_samples;
+ int ret;
+
+ ret = pac1921_lookup_int_num_samples(num_samples);
+ if (ret < 0)
+ return ret;
+
+ n_samples = (u8)ret;
+
+ if (priv->n_samples == n_samples)
+ return 0;
+
+ reg_val = FIELD_PREP(PAC1921_INT_CFG_SMPL_MASK, n_samples);
+
+ ret = pac1921_update_cfg_reg(priv, PAC1921_REG_INT_CFG,
+ PAC1921_INT_CFG_SMPL_MASK, reg_val);
+ if (ret)
+ return ret;
+
+ priv->n_samples = n_samples;
+
+ priv->integr_period_usecs = pac1921_int_periods_usecs[priv->n_samples];
+
+ return 0;
+}
+
+static int pac1921_write_raw_get_fmt(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ long info)
+{
+ switch (info) {
+ case IIO_CHAN_INFO_SCALE:
+ return IIO_VAL_INT_PLUS_NANO;
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int pac1921_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int val,
+ int val2, long mask)
+{
+ struct pac1921_priv *priv = iio_priv(indio_dev);
+
+ guard(mutex)(&priv->lock);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SCALE:
+ return pac1921_update_gain_from_scale(priv, chan, val, val2);
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ return pac1921_update_int_num_samples(priv, val);
+ default:
+ return -EINVAL;
+ }
+}
+
+static int pac1921_read_label(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, char *label)
+{
+ switch (chan->channel) {
+ case PAC1921_CHAN_VBUS:
+ return sprintf(label, "vbus\n");
+ case PAC1921_CHAN_VSENSE:
+ return sprintf(label, "vsense\n");
+ case PAC1921_CHAN_CURRENT:
+ return sprintf(label, "current\n");
+ case PAC1921_CHAN_POWER:
+ return sprintf(label, "power\n");
+ default:
+ return -EINVAL;
+ }
+}
+
+static int pac1921_read_event_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir)
+{
+ struct pac1921_priv *priv = iio_priv(indio_dev);
+
+ guard(mutex)(&priv->lock);
+
+ switch (chan->channel) {
+ case PAC1921_CHAN_VBUS:
+ return !!(priv->ovf_enabled_events & PAC1921_OVERFLOW_VBOV);
+ case PAC1921_CHAN_VSENSE:
+ case PAC1921_CHAN_CURRENT:
+ return !!(priv->ovf_enabled_events & PAC1921_OVERFLOW_VSOV);
+ case PAC1921_CHAN_POWER:
+ return !!(priv->ovf_enabled_events & PAC1921_OVERFLOW_VPOV);
+ default:
+ return -EINVAL;
+ }
+}
+
+static int pac1921_write_event_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir, int state)
+{
+ struct pac1921_priv *priv = iio_priv(indio_dev);
+ u8 ovf_bit;
+
+ guard(mutex)(&priv->lock);
+
+ switch (chan->channel) {
+ case PAC1921_CHAN_VBUS:
+ ovf_bit = PAC1921_OVERFLOW_VBOV;
+ break;
+ case PAC1921_CHAN_VSENSE:
+ case PAC1921_CHAN_CURRENT:
+ ovf_bit = PAC1921_OVERFLOW_VSOV;
+ break;
+ case PAC1921_CHAN_POWER:
+ ovf_bit = PAC1921_OVERFLOW_VPOV;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (state)
+ priv->ovf_enabled_events |= ovf_bit;
+ else
+ priv->ovf_enabled_events &= ~ovf_bit;
+
+ return 0;
+}
+
+static int pac1921_read_event_value(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info, int *val,
+ int *val2)
+{
+ switch (info) {
+ case IIO_EV_INFO_VALUE:
+ *val = PAC1921_RES_RESOLUTION;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info pac1921_iio = {
+ .read_raw = pac1921_read_raw,
+ .read_avail = pac1921_read_avail,
+ .write_raw = pac1921_write_raw,
+ .write_raw_get_fmt = pac1921_write_raw_get_fmt,
+ .read_label = pac1921_read_label,
+ .read_event_config = pac1921_read_event_config,
+ .write_event_config = pac1921_write_event_config,
+ .read_event_value = pac1921_read_event_value,
+};
+
+static ssize_t pac1921_read_shunt_resistor(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ char *buf)
+{
+ struct pac1921_priv *priv = iio_priv(indio_dev);
+ int vals[2];
+
+ if (chan->channel != PAC1921_CHAN_CURRENT)
+ return -EINVAL;
+
+ guard(mutex)(&priv->lock);
+
+ vals[0] = (int)priv->rshunt_uohm;
+ vals[1] = MICRO;
+
+ return iio_format_value(buf, IIO_VAL_FRACTIONAL, 1, vals);
+}
+
+static ssize_t pac1921_write_shunt_resistor(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ const char *buf, size_t len)
+{
+ struct pac1921_priv *priv = iio_priv(indio_dev);
+ u64 rshunt_uohm;
+ int val, val_fract;
+ int ret;
+
+ if (chan->channel != PAC1921_CHAN_CURRENT)
+ return -EINVAL;
+
+ ret = iio_str_to_fixpoint(buf, 100000, &val, &val_fract);
+ if (ret)
+ return ret;
+
+ rshunt_uohm = (u32)val * MICRO + (u32)val_fract;
+ if (rshunt_uohm == 0 || rshunt_uohm > INT_MAX)
+ return -EINVAL;
+
+ guard(mutex)(&priv->lock);
+
+ priv->rshunt_uohm = (u32)rshunt_uohm;
+
+ pac1921_calc_current_scales(priv);
+
+ return len;
+}
+
+/*
+ * Emit on sysfs the list of available scales contained in scales_tbl
+ *
+ * TODO:: this function can be replaced with iio_format_avail_list() if the
+ * latter will ever be exported.
+ *
+ * Must be called with lock held if the scales_tbl can change runtime (e.g. for
+ * the current scales table)
+ */
+static ssize_t pac1921_format_scale_avail(const int (*const scales_tbl)[2],
+ size_t size, char *buf)
+{
+ ssize_t len = 0;
+
+ for (unsigned int i = 0; i < size; i++) {
+ if (i != 0) {
+ len += sysfs_emit_at(buf, len, " ");
+ if (len >= PAGE_SIZE)
+ return -EFBIG;
+ }
+ len += sysfs_emit_at(buf, len, "%d.%09d", scales_tbl[i][0],
+ scales_tbl[i][1]);
+ if (len >= PAGE_SIZE)
+ return -EFBIG;
+ }
+
+ len += sysfs_emit_at(buf, len, "\n");
+ return len;
+}
+
+/*
+ * Read available scales for a specific channel
+ *
+ * NOTE: using extended info insted of iio.read_avail() because access to
+ * current scales must be locked as they depend on shunt resistor which may
+ * change runtime. Caller of iio.read_avail() would access the table unlocked
+ * instead.
+ */
+static ssize_t pac1921_read_scale_avail(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ char *buf)
+{
+ struct pac1921_priv *priv = iio_priv(indio_dev);
+ const int (*scales_tbl)[2];
+ size_t size;
+
+ switch (chan->channel) {
+ case PAC1921_CHAN_VBUS:
+ scales_tbl = pac1921_vbus_scales;
+ size = ARRAY_SIZE(pac1921_vbus_scales);
+ return pac1921_format_scale_avail(scales_tbl, size, buf);
+
+ case PAC1921_CHAN_VSENSE:
+ scales_tbl = pac1921_vsense_scales;
+ size = ARRAY_SIZE(pac1921_vsense_scales);
+ return pac1921_format_scale_avail(scales_tbl, size, buf);
+
+ case PAC1921_CHAN_CURRENT: {
+ guard(mutex)(&priv->lock);
+ scales_tbl = priv->current_scales;
+ size = ARRAY_SIZE(priv->current_scales);
+ return pac1921_format_scale_avail(scales_tbl, size, buf);
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+#define PAC1921_EXT_INFO_SCALE_AVAIL { \
+ .name = "scale_available", \
+ .read = pac1921_read_scale_avail, \
+ .shared = IIO_SEPARATE, \
+}
+
+static const struct iio_chan_spec_ext_info pac1921_ext_info_voltage[] = {
+ PAC1921_EXT_INFO_SCALE_AVAIL,
+ {}
+};
+
+static const struct iio_chan_spec_ext_info pac1921_ext_info_current[] = {
+ PAC1921_EXT_INFO_SCALE_AVAIL,
+ {
+ .name = "shunt_resistor",
+ .read = pac1921_read_shunt_resistor,
+ .write = pac1921_write_shunt_resistor,
+ .shared = IIO_SEPARATE,
+ },
+ {}
+};
+
+static const struct iio_event_spec pac1921_overflow_event[] = {
+ {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_RISING,
+ .mask_shared_by_all = BIT(IIO_EV_INFO_VALUE),
+ .mask_separate = BIT(IIO_EV_INFO_ENABLE),
+ },
+};
+
+static const struct iio_chan_spec pac1921_channels[] = {
+ {
+ .type = IIO_VOLTAGE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_all =
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
+ BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ .info_mask_shared_by_all_available =
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+ .channel = PAC1921_CHAN_VBUS,
+ .address = PAC1921_REG_VBUS,
+ .scan_index = PAC1921_CHAN_VBUS,
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 10,
+ .storagebits = 16,
+ .endianness = IIO_CPU
+ },
+ .indexed = 1,
+ .event_spec = pac1921_overflow_event,
+ .num_event_specs = ARRAY_SIZE(pac1921_overflow_event),
+ .ext_info = pac1921_ext_info_voltage,
+ },
+ {
+ .type = IIO_VOLTAGE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_all =
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
+ BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ .info_mask_shared_by_all_available =
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+ .channel = PAC1921_CHAN_VSENSE,
+ .address = PAC1921_REG_VSENSE,
+ .scan_index = PAC1921_CHAN_VSENSE,
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 10,
+ .storagebits = 16,
+ .endianness = IIO_CPU
+ },
+ .indexed = 1,
+ .event_spec = pac1921_overflow_event,
+ .num_event_specs = ARRAY_SIZE(pac1921_overflow_event),
+ .ext_info = pac1921_ext_info_voltage,
+ },
+ {
+ .type = IIO_CURRENT,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_all =
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
+ BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ .info_mask_shared_by_all_available =
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+ .channel = PAC1921_CHAN_CURRENT,
+ .address = PAC1921_REG_VSENSE,
+ .scan_index = PAC1921_CHAN_CURRENT,
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 10,
+ .storagebits = 16,
+ .endianness = IIO_CPU
+ },
+ .event_spec = pac1921_overflow_event,
+ .num_event_specs = ARRAY_SIZE(pac1921_overflow_event),
+ .ext_info = pac1921_ext_info_current,
+ },
+ {
+ .type = IIO_POWER,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_all =
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
+ BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ .info_mask_shared_by_all_available =
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+ .channel = PAC1921_CHAN_POWER,
+ .address = PAC1921_REG_VPOWER,
+ .scan_index = PAC1921_CHAN_POWER,
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 10,
+ .storagebits = 16,
+ .endianness = IIO_CPU
+ },
+ .event_spec = pac1921_overflow_event,
+ .num_event_specs = ARRAY_SIZE(pac1921_overflow_event),
+ },
+ IIO_CHAN_SOFT_TIMESTAMP(PAC1921_NUM_MEAS_CHANS),
+};
+
+static irqreturn_t pac1921_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *idev = pf->indio_dev;
+ struct pac1921_priv *priv = iio_priv(idev);
+ int ret;
+ int bit;
+ int ch = 0;
+
+ guard(mutex)(&priv->lock);
+
+ if (!pac1921_data_ready(priv))
+ goto done;
+
+ ret = pac1921_check_push_overflow(idev, pf->timestamp);
+ if (ret)
+ goto done;
+
+ iio_for_each_active_channel(idev, bit) {
+ u16 val;
+
+ ret = pac1921_read_res(priv, idev->channels[ch].address, &val);
+ if (ret)
+ goto done;
+
+ priv->scan.chan[ch++] = val;
+ }
+
+ iio_push_to_buffers_with_timestamp(idev, &priv->scan, pf->timestamp);
+
+done:
+ iio_trigger_notify_done(idev->trig);
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * Initialize device by writing initial configuration and putting it into
+ * integration state.
+ *
+ * Must be called with lock held when called after first initialization
+ * (e.g. from pm resume)
+ */
+static int pac1921_init(struct pac1921_priv *priv)
+{
+ unsigned int val;
+ int ret;
+
+ /* Enter READ state before configuration */
+ ret = regmap_update_bits(priv->regmap, PAC1921_REG_INT_CFG,
+ PAC1921_INT_CFG_INTEN, 0);
+ if (ret)
+ return ret;
+
+ /* Configure gains, use 14-bits measurement resolution (HW default) */
+ val = FIELD_PREP(PAC1921_GAIN_DI_GAIN_MASK, priv->di_gain) |
+ FIELD_PREP(PAC1921_GAIN_DV_GAIN_MASK, priv->dv_gain);
+ ret = regmap_write(priv->regmap, PAC1921_REG_GAIN_CFG, val);
+ if (ret)
+ return ret;
+
+ /*
+ * Configure integration:
+ * - num of integration samples
+ * - filters enabled (HW default)
+ * - set READ/INT pin override (RIOV) to control operation mode via
+ * register instead of pin
+ */
+ val = FIELD_PREP(PAC1921_INT_CFG_SMPL_MASK, priv->n_samples) |
+ PAC1921_INT_CFG_VSFEN | PAC1921_INT_CFG_VBFEN |
+ PAC1921_INT_CFG_RIOV;
+ ret = regmap_write(priv->regmap, PAC1921_REG_INT_CFG, val);
+ if (ret)
+ return ret;
+
+ /*
+ * Init control register:
+ * - VPower free run integration mode
+ * - OUT pin full scale range: 3V (HW detault)
+ * - no timeout, no sleep, no sleep override, no recalc (HW defaults)
+ */
+ val = FIELD_PREP(PAC1921_CONTROL_MXSL_MASK,
+ PAC1921_MXSL_VPOWER_FREE_RUN);
+ ret = regmap_write(priv->regmap, PAC1921_REG_CONTROL, val);
+ if (ret)
+ return ret;
+
+ /* Enable integration */
+ ret = regmap_update_bits(priv->regmap, PAC1921_REG_INT_CFG,
+ PAC1921_INT_CFG_INTEN, PAC1921_INT_CFG_INTEN);
+ if (ret)
+ return ret;
+
+ priv->first_integr_started = true;
+ priv->integr_started_time_jiffies = jiffies;
+ priv->integr_period_usecs = pac1921_int_periods_usecs[priv->n_samples];
+
+ return 0;
+}
+
+static int pac1921_suspend(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct pac1921_priv *priv = iio_priv(indio_dev);
+ int ret;
+
+ guard(mutex)(&priv->lock);
+
+ priv->first_integr_started = false;
+ priv->first_integr_done = false;
+
+ ret = regmap_update_bits(priv->regmap, PAC1921_REG_INT_CFG,
+ PAC1921_INT_CFG_INTEN, 0);
+ if (ret)
+ return ret;
+
+ ret = regmap_update_bits(priv->regmap, PAC1921_REG_CONTROL,
+ PAC1921_CONTROL_SLEEP, PAC1921_CONTROL_SLEEP);
+ if (ret)
+ return ret;
+
+ return regulator_disable(priv->vdd);
+
+}
+
+static int pac1921_resume(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct pac1921_priv *priv = iio_priv(indio_dev);
+ int ret;
+
+ guard(mutex)(&priv->lock);
+
+ ret = regulator_enable(priv->vdd);
+ if (ret)
+ return ret;
+
+ msleep(PAC1921_POWERUP_TIME_MS);
+
+ return pac1921_init(priv);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(pac1921_pm_ops, pac1921_suspend,
+ pac1921_resume);
+
+static void pac1921_regulator_disable(void *data)
+{
+ struct regulator *regulator = data;
+
+ regulator_disable(regulator);
+}
+
+static int pac1921_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct pac1921_priv *priv;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ priv = iio_priv(indio_dev);
+ priv->client = client;
+ i2c_set_clientdata(client, indio_dev);
+
+ priv->regmap = devm_regmap_init_i2c(client, &pac1921_regmap_config);
+ if (IS_ERR(priv->regmap))
+ dev_err_probe(dev, (int)PTR_ERR(priv->regmap),
+ "Cannot initialize register map\n");
+
+ devm_mutex_init(dev, &priv->lock);
+
+ priv->dv_gain = PAC1921_DEFAULT_DV_GAIN;
+ priv->di_gain = PAC1921_DEFAULT_DI_GAIN;
+ priv->n_samples = PAC1921_DEFAULT_NUM_SAMPLES;
+
+ ret = device_property_read_u32(dev, "shunt-resistor-micro-ohms",
+ &priv->rshunt_uohm);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Cannot read shunt resistor property\n");
+ if (priv->rshunt_uohm == 0 || priv->rshunt_uohm > INT_MAX)
+ return dev_err_probe(dev, -EINVAL,
+ "Invalid shunt resistor: %u\n",
+ priv->rshunt_uohm);
+
+ pac1921_calc_current_scales(priv);
+
+ priv->vdd = devm_regulator_get(dev, "vdd");
+ if (IS_ERR(priv->vdd))
+ return dev_err_probe(dev, (int)PTR_ERR(priv->vdd),
+ "Cannot get vdd regulator\n");
+
+ ret = regulator_enable(priv->vdd);
+ if (ret)
+ return dev_err_probe(dev, ret, "Cannot enable vdd regulator\n");
+
+ ret = devm_add_action_or_reset(dev, pac1921_regulator_disable,
+ priv->vdd);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Cannot add action for vdd regulator disposal\n");
+
+ msleep(PAC1921_POWERUP_TIME_MS);
+
+ ret = pac1921_init(priv);
+ if (ret)
+ return dev_err_probe(dev, ret, "Cannot initialize device\n");
+
+ priv->iio_info = pac1921_iio;
+
+ indio_dev->name = "pac1921";
+ indio_dev->info = &priv->iio_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = pac1921_channels;
+ indio_dev->num_channels = ARRAY_SIZE(pac1921_channels);
+
+ ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
+ &iio_pollfunc_store_time,
+ &pac1921_trigger_handler, NULL);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Cannot setup IIO triggered buffer\n");
+
+ ret = devm_iio_device_register(dev, indio_dev);
+ if (ret)
+ return dev_err_probe(dev, ret, "Cannot register IIO device\n");
+
+ return 0;
+}
+
+static const struct i2c_device_id pac1921_id[] = {
+ { .name = "pac1921", 0 },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, pac1921_id);
+
+static const struct of_device_id pac1921_of_match[] = {
+ { .compatible = "microchip,pac1921" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, pac1921_of_match);
+
+static struct i2c_driver pac1921_driver = {
+ .driver = {
+ .name = "pac1921",
+ .pm = pm_sleep_ptr(&pac1921_pm_ops),
+ .of_match_table = pac1921_of_match,
+ },
+ .probe = pac1921_probe,
+ .id_table = pac1921_id,
+};
+
+module_i2c_driver(pac1921_driver);
+
+MODULE_AUTHOR("Matteo Martelli <matteomartelli3@gmail.com>");
+MODULE_DESCRIPTION("IIO driver for PAC1921 High-Side Power/Current Monitor");
+MODULE_LICENSE("GPL");
projects / thirdparty / kernel / linux.git / commitdiff
