diff options
Diffstat (limited to 'drivers/iio/adc/rohm-bd79124.c')
| -rw-r--r-- | drivers/iio/adc/rohm-bd79124.c | 1146 |
1 files changed, 1146 insertions, 0 deletions
diff --git a/drivers/iio/adc/rohm-bd79124.c b/drivers/iio/adc/rohm-bd79124.c new file mode 100644 index 000000000000..bb7c93ae4055 --- /dev/null +++ b/drivers/iio/adc/rohm-bd79124.c @@ -0,0 +1,1146 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ROHM ADC driver for BD79124 ADC/GPO device + * https://fscdn.rohm.com/en/products/databook/datasheet/ic/data_converter/dac/bd79124muf-c-e.pdf + * + * Copyright (c) 2025, ROHM Semiconductor. + */ + +#include <linux/array_size.h> +#include <linux/bitfield.h> +#include <linux/bitmap.h> +#include <linux/bits.h> +#include <linux/device.h> +#include <linux/delay.h> +#include <linux/devm-helpers.h> +#include <linux/err.h> +#include <linux/gpio/driver.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/irqreturn.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/regmap.h> +#include <linux/types.h> + +#include <asm/byteorder.h> + +#include <linux/iio/events.h> +#include <linux/iio/iio.h> +#include <linux/iio/adc-helpers.h> + +#define BD79124_I2C_MULTI_READ 0x30 +#define BD79124_I2C_MULTI_WRITE 0x28 +#define BD79124_REG_MAX 0xaf + +#define BD79124_REG_SYSTEM_STATUS 0x00 +#define BD79124_REG_GEN_CFG 0x01 +#define BD79124_REG_OPMODE_CFG 0x04 +#define BD79124_REG_PINCFG 0x05 +#define BD79124_REG_GPO_VAL 0x0B +#define BD79124_REG_SEQ_CFG 0x10 +#define BD79124_REG_MANUAL_CHANNELS 0x11 +#define BD79124_REG_AUTO_CHANNELS 0x12 +#define BD79124_REG_ALERT_CH_SEL 0x14 +#define BD79124_REG_EVENT_FLAG 0x18 +#define BD79124_REG_EVENT_FLAG_HI 0x1a +#define BD79124_REG_EVENT_FLAG_LO 0x1c +#define BD79124_REG_HYSTERESIS_CH0 0x20 +#define BD79124_REG_EVENTCOUNT_CH0 0x22 +#define BD79124_REG_RECENT_CH0_LSB 0xa0 +#define BD79124_REG_RECENT_CH7_MSB 0xaf + +#define BD79124_ADC_BITS 12 + +/* Masks for the BD79124_REG_OPMODE_CFG */ +#define BD79124_MSK_CONV_MODE GENMASK(6, 5) +#define BD79124_CONV_MODE_MANSEQ 0 +#define BD79124_CONV_MODE_AUTO 1 +#define BD79124_MSK_AUTO_INTERVAL GENMASK(1, 0) +#define BD79124_INTERVAL_750_US 0 + +/* Masks for the BD79124_REG_GEN_CFG */ +#define BD79124_MSK_DWC_EN BIT(4) +#define BD79124_MSK_STATS_EN BIT(5) + +/* Masks for the BD79124_REG_SEQ_CFG */ +#define BD79124_MSK_SEQ_START BIT(4) +#define BD79124_MSK_SEQ_MODE GENMASK(1, 0) +#define BD79124_MSK_SEQ_MANUAL 0 +#define BD79124_MSK_SEQ_SEQ 1 + +#define BD79124_MSK_HYSTERESIS GENMASK(3, 0) +#define BD79124_LOW_LIMIT_MIN 0 +#define BD79124_HIGH_LIMIT_MAX GENMASK(11, 0) + +/* + * The high limit, low limit and last measurement result are each stored in + * 2 consequtive registers. 4 bits are in the high bits of the first register + * and 8 bits in the next register. + * + * These macros return the address of the first reg for the given channel. + */ +#define BD79124_GET_HIGH_LIMIT_REG(ch) (BD79124_REG_HYSTERESIS_CH0 + (ch) * 4) +#define BD79124_GET_LOW_LIMIT_REG(ch) (BD79124_REG_EVENTCOUNT_CH0 + (ch) * 4) +#define BD79124_GET_LIMIT_REG(ch, dir) ((dir) == IIO_EV_DIR_RISING ? \ + BD79124_GET_HIGH_LIMIT_REG(ch) : BD79124_GET_LOW_LIMIT_REG(ch)) +#define BD79124_GET_RECENT_RES_REG(ch) (BD79124_REG_RECENT_CH0_LSB + (ch) * 2) + +/* + * The hysteresis for a channel is stored in the same register where the + * 4 bits of high limit reside. + */ +#define BD79124_GET_HYSTERESIS_REG(ch) BD79124_GET_HIGH_LIMIT_REG(ch) + +#define BD79124_MAX_NUM_CHANNELS 8 + +struct bd79124_data { + s64 timestamp; + struct regmap *map; + struct device *dev; + int vmax; + /* + * Keep measurement status so read_raw() knows if the measurement needs + * to be started. + */ + int alarm_monitored[BD79124_MAX_NUM_CHANNELS]; + /* + * The BD79124 does not allow disabling/enabling limit separately for + * one direction only. Hence, we do the disabling by changing the limit + * to maximum/minimum measurable value. This means we need to cache + * the limit in order to maintain it over the time limit is disabled. + */ + u16 alarm_r_limit[BD79124_MAX_NUM_CHANNELS]; + u16 alarm_f_limit[BD79124_MAX_NUM_CHANNELS]; + /* Bitmask of disabled events (for rate limiting) for each channel. */ + int alarm_suppressed[BD79124_MAX_NUM_CHANNELS]; + /* + * The BD79124 is configured to run the measurements in the background. + * This is done for the event monitoring as well as for the read_raw(). + * Protect the measurement starting/stopping using a mutex. + */ + struct mutex mutex; + struct delayed_work alm_enable_work; + struct gpio_chip gc; + u8 gpio_valid_mask; +}; + +static const struct regmap_range bd79124_ro_ranges[] = { + { + .range_min = BD79124_REG_EVENT_FLAG, + .range_max = BD79124_REG_EVENT_FLAG, + }, { + .range_min = BD79124_REG_RECENT_CH0_LSB, + .range_max = BD79124_REG_RECENT_CH7_MSB, + }, +}; + +static const struct regmap_access_table bd79124_ro_regs = { + .no_ranges = &bd79124_ro_ranges[0], + .n_no_ranges = ARRAY_SIZE(bd79124_ro_ranges), +}; + +static const struct regmap_range bd79124_volatile_ranges[] = { + { + .range_min = BD79124_REG_RECENT_CH0_LSB, + .range_max = BD79124_REG_RECENT_CH7_MSB, + }, { + .range_min = BD79124_REG_EVENT_FLAG, + .range_max = BD79124_REG_EVENT_FLAG, + }, { + .range_min = BD79124_REG_EVENT_FLAG_HI, + .range_max = BD79124_REG_EVENT_FLAG_HI, + }, { + .range_min = BD79124_REG_EVENT_FLAG_LO, + .range_max = BD79124_REG_EVENT_FLAG_LO, + }, { + .range_min = BD79124_REG_SYSTEM_STATUS, + .range_max = BD79124_REG_SYSTEM_STATUS, + }, +}; + +static const struct regmap_access_table bd79124_volatile_regs = { + .yes_ranges = &bd79124_volatile_ranges[0], + .n_yes_ranges = ARRAY_SIZE(bd79124_volatile_ranges), +}; + +static const struct regmap_range bd79124_precious_ranges[] = { + { + .range_min = BD79124_REG_EVENT_FLAG_HI, + .range_max = BD79124_REG_EVENT_FLAG_HI, + }, { + .range_min = BD79124_REG_EVENT_FLAG_LO, + .range_max = BD79124_REG_EVENT_FLAG_LO, + }, +}; + +static const struct regmap_access_table bd79124_precious_regs = { + .yes_ranges = &bd79124_precious_ranges[0], + .n_yes_ranges = ARRAY_SIZE(bd79124_precious_ranges), +}; + +static const struct regmap_config bd79124_regmap = { + .reg_bits = 16, + .val_bits = 8, + .read_flag_mask = BD79124_I2C_MULTI_READ, + .write_flag_mask = BD79124_I2C_MULTI_WRITE, + .max_register = BD79124_REG_MAX, + .cache_type = REGCACHE_MAPLE, + .volatile_table = &bd79124_volatile_regs, + .wr_table = &bd79124_ro_regs, + .precious_table = &bd79124_precious_regs, +}; + +static int bd79124gpo_direction_get(struct gpio_chip *gc, unsigned int offset) +{ + return GPIO_LINE_DIRECTION_OUT; +} + +static int bd79124gpo_set(struct gpio_chip *gc, unsigned int offset, int value) +{ + struct bd79124_data *data = gpiochip_get_data(gc); + + return regmap_assign_bits(data->map, BD79124_REG_GPO_VAL, BIT(offset), + value); +} + +static int bd79124gpo_set_multiple(struct gpio_chip *gc, unsigned long *mask, + unsigned long *bits) +{ + unsigned int all_gpos; + int ret; + struct bd79124_data *data = gpiochip_get_data(gc); + + /* + * Ensure all GPIOs in 'mask' are set to be GPIOs + * The valid_mask was not obeyed by the gpiolib in all cases prior the + * https://lore.kernel.org/all/cd5e067b80e1bb590027bc3bfa817e7f794f21c3.1741180097.git.mazziesaccount@gmail.com/ + * + * Keep this check here for a couple of cycles. + */ + ret = regmap_read(data->map, BD79124_REG_PINCFG, &all_gpos); + if (ret) + return ret; + + if (all_gpos ^ *mask) { + dev_dbg(data->dev, "Invalid mux config. Can't set value.\n"); + + return -EINVAL; + } + + return regmap_update_bits(data->map, BD79124_REG_GPO_VAL, *mask, *bits); +} + +static int bd79124_init_valid_mask(struct gpio_chip *gc, + unsigned long *valid_mask, + unsigned int ngpios) +{ + struct bd79124_data *data = gpiochip_get_data(gc); + + *valid_mask = data->gpio_valid_mask; + + return 0; +} + +/* Template for GPIO chip */ +static const struct gpio_chip bd79124gpo_chip = { + .label = "bd79124-gpo", + .get_direction = bd79124gpo_direction_get, + .set_rv = bd79124gpo_set, + .set_multiple_rv = bd79124gpo_set_multiple, + .init_valid_mask = bd79124_init_valid_mask, + .can_sleep = true, + .ngpio = 8, + .base = -1, +}; + +struct bd79124_raw { + u8 val_bit3_0; /* Is set in high bits of the byte */ + u8 val_bit11_4; +}; +#define BD79124_RAW_TO_INT(r) ((r.val_bit11_4 << 4) | (r.val_bit3_0 >> 4)) +#define BD79124_INT_TO_RAW(val) { \ + .val_bit11_4 = (val) >> 4, \ + .val_bit3_0 = (val) << 4, \ +} + +/* + * The high and low limits as well as the recent result values are stored in + * the same way in 2 consequent registers. The first register contains 4 bits + * of the value. These bits are stored in the high bits [7:4] of register, but + * they represent the low bits [3:0] of the value. + * The value bits [11:4] are stored in the next register. + * + * Read data from register and convert to integer. + */ +static int bd79124_read_reg_to_int(struct bd79124_data *data, int reg, + unsigned int *val) +{ + int ret; + struct bd79124_raw raw; + + ret = regmap_bulk_read(data->map, reg, &raw, sizeof(raw)); + if (ret) { + dev_dbg(data->dev, "bulk_read failed %d\n", ret); + + return ret; + } + + *val = BD79124_RAW_TO_INT(raw); + + return 0; +} + +/* + * The high and low limits as well as the recent result values are stored in + * the same way in 2 consequent registers. The first register contains 4 bits + * of the value. These bits are stored in the high bits [7:4] of register, but + * they represent the low bits [3:0] of the value. + * The value bits [11:4] are stored in the next register. + * + * Convert the integer to register format and write it using rmw cycle. + */ +static int bd79124_write_int_to_reg(struct bd79124_data *data, int reg, + unsigned int val) +{ + struct bd79124_raw raw = BD79124_INT_TO_RAW(val); + unsigned int tmp; + int ret; + + ret = regmap_read(data->map, reg, &tmp); + if (ret) + return ret; + + raw.val_bit3_0 |= (tmp & 0xf); + + return regmap_bulk_write(data->map, reg, &raw, sizeof(raw)); +} + +static const struct iio_event_spec bd79124_events[] = { + { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_RISING, + .mask_separate = BIT(IIO_EV_INFO_VALUE) | + BIT(IIO_EV_INFO_ENABLE), + }, + { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_FALLING, + .mask_separate = BIT(IIO_EV_INFO_VALUE) | + BIT(IIO_EV_INFO_ENABLE), + }, + { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_EITHER, + .mask_separate = BIT(IIO_EV_INFO_HYSTERESIS), + }, +}; + +static const struct iio_chan_spec bd79124_chan_template_noirq = { + .type = IIO_VOLTAGE, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), + .indexed = 1, +}; + +static const struct iio_chan_spec bd79124_chan_template = { + .type = IIO_VOLTAGE, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), + .indexed = 1, + .event_spec = bd79124_events, + .num_event_specs = ARRAY_SIZE(bd79124_events), +}; + +static int bd79124_read_event_value(struct iio_dev *iio_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) +{ + struct bd79124_data *data = iio_priv(iio_dev); + int ret, reg; + + if (chan->channel >= BD79124_MAX_NUM_CHANNELS) + return -EINVAL; + + switch (info) { + case IIO_EV_INFO_VALUE: + if (dir == IIO_EV_DIR_RISING) + *val = data->alarm_r_limit[chan->channel]; + else if (dir == IIO_EV_DIR_FALLING) + *val = data->alarm_f_limit[chan->channel]; + else + return -EINVAL; + + return IIO_VAL_INT; + + case IIO_EV_INFO_HYSTERESIS: + reg = BD79124_GET_HYSTERESIS_REG(chan->channel); + ret = regmap_read(data->map, reg, val); + if (ret) + return ret; + + *val &= BD79124_MSK_HYSTERESIS; + /* + * The data-sheet says the hysteresis register value needs to be + * shifted left by 3. + */ + *val <<= 3; + + return IIO_VAL_INT; + + default: + return -EINVAL; + } +} + +static int bd79124_start_measurement(struct bd79124_data *data, int chan) +{ + unsigned int val, regval; + int ret; + + /* See if already started */ + ret = regmap_read(data->map, BD79124_REG_AUTO_CHANNELS, &val); + if (val & BIT(chan)) + return 0; + + /* + * The sequencer must be stopped when channels are added/removed from + * the list of the measured channels to ensure the new channel + * configuration is used. + */ + ret = regmap_clear_bits(data->map, BD79124_REG_SEQ_CFG, + BD79124_MSK_SEQ_START); + if (ret) + return ret; + + ret = regmap_write(data->map, BD79124_REG_AUTO_CHANNELS, val | BIT(chan)); + if (ret) + return ret; + + ret = regmap_set_bits(data->map, BD79124_REG_SEQ_CFG, + BD79124_MSK_SEQ_START); + if (ret) + return ret; + + /* + * Start the measurement at the background. Don't bother checking if + * it was started, regmap has cache. + */ + regval = FIELD_PREP(BD79124_MSK_CONV_MODE, BD79124_CONV_MODE_AUTO); + + return regmap_update_bits(data->map, BD79124_REG_OPMODE_CFG, + BD79124_MSK_CONV_MODE, regval); +} + +static int bd79124_stop_measurement(struct bd79124_data *data, int chan) +{ + unsigned int enabled_chans; + int ret; + + /* See if already stopped */ + ret = regmap_read(data->map, BD79124_REG_AUTO_CHANNELS, &enabled_chans); + if (!(enabled_chans & BIT(chan))) + return 0; + + ret = regmap_clear_bits(data->map, BD79124_REG_SEQ_CFG, + BD79124_MSK_SEQ_START); + + /* Clear the channel from the measured channels */ + enabled_chans &= ~BIT(chan); + ret = regmap_write(data->map, BD79124_REG_AUTO_CHANNELS, + enabled_chans); + if (ret) + return ret; + + /* + * Stop background conversion for power saving if it was the last + * channel. + */ + if (!enabled_chans) { + int regval = FIELD_PREP(BD79124_MSK_CONV_MODE, + BD79124_CONV_MODE_MANSEQ); + + ret = regmap_update_bits(data->map, BD79124_REG_OPMODE_CFG, + BD79124_MSK_CONV_MODE, regval); + if (ret) + return ret; + } + + return regmap_set_bits(data->map, BD79124_REG_SEQ_CFG, + BD79124_MSK_SEQ_START); +} + +static int bd79124_read_event_config(struct iio_dev *iio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir) +{ + struct bd79124_data *data = iio_priv(iio_dev); + + if (chan->channel >= BD79124_MAX_NUM_CHANNELS) + return -EINVAL; + + return !!(data->alarm_monitored[chan->channel] & BIT(dir)); +} + +static int bd79124_disable_event(struct bd79124_data *data, + enum iio_event_direction dir, int channel) +{ + int dir_bit = BIT(dir); + int reg; + unsigned int limit; + + guard(mutex)(&data->mutex); + + /* + * Set thresholds either to 0 or to 2^12 - 1 as appropriate to prevent + * alerts and thus disable event generation. + */ + if (dir == IIO_EV_DIR_RISING) { + reg = BD79124_GET_HIGH_LIMIT_REG(channel); + limit = BD79124_HIGH_LIMIT_MAX; + } else if (dir == IIO_EV_DIR_FALLING) { + reg = BD79124_GET_LOW_LIMIT_REG(channel); + limit = BD79124_LOW_LIMIT_MIN; + } else { + return -EINVAL; + } + + data->alarm_monitored[channel] &= ~dir_bit; + + /* + * Stop measurement if there is no more events to monitor. + * We don't bother checking the retval because the limit + * setting should in any case effectively disable the alarm. + */ + if (!data->alarm_monitored[channel]) { + bd79124_stop_measurement(data, channel); + regmap_clear_bits(data->map, BD79124_REG_ALERT_CH_SEL, + BIT(channel)); + } + + return bd79124_write_int_to_reg(data, reg, limit); +} + +static int bd79124_enable_event(struct bd79124_data *data, + enum iio_event_direction dir, + unsigned int channel) +{ + int dir_bit = BIT(dir); + int reg, ret; + u16 *limit; + + guard(mutex)(&data->mutex); + ret = bd79124_start_measurement(data, channel); + if (ret) + return ret; + + data->alarm_monitored[channel] |= dir_bit; + + /* Add the channel to the list of monitored channels */ + ret = regmap_set_bits(data->map, BD79124_REG_ALERT_CH_SEL, BIT(channel)); + if (ret) + return ret; + + if (dir == IIO_EV_DIR_RISING) { + limit = &data->alarm_f_limit[channel]; + reg = BD79124_GET_HIGH_LIMIT_REG(channel); + } else { + limit = &data->alarm_f_limit[channel]; + reg = BD79124_GET_LOW_LIMIT_REG(channel); + } + /* + * Don't write the new limit to the hardware if we are in the + * rate-limit period. The timer which re-enables the event will set + * the limit. + */ + if (!(data->alarm_suppressed[channel] & dir_bit)) { + ret = bd79124_write_int_to_reg(data, reg, *limit); + if (ret) + return ret; + } + + /* + * Enable comparator. Trust the regmap cache, no need to check + * if it was already enabled. + * + * We could do this in the hw-init, but there may be users who + * never enable alarms and for them it makes sense to not + * enable the comparator at probe. + */ + return regmap_set_bits(data->map, BD79124_REG_GEN_CFG, + BD79124_MSK_DWC_EN); +} + +static int bd79124_write_event_config(struct iio_dev *iio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, bool state) +{ + struct bd79124_data *data = iio_priv(iio_dev); + + if (chan->channel >= BD79124_MAX_NUM_CHANNELS) + return -EINVAL; + + if (state) + return bd79124_enable_event(data, dir, chan->channel); + + return bd79124_disable_event(data, dir, chan->channel); +} + +static int bd79124_write_event_value(struct iio_dev *iio_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) +{ + struct bd79124_data *data = iio_priv(iio_dev); + int reg; + + if (chan->channel >= BD79124_MAX_NUM_CHANNELS) + return -EINVAL; + + switch (info) { + case IIO_EV_INFO_VALUE: + { + guard(mutex)(&data->mutex); + + if (dir == IIO_EV_DIR_RISING) { + data->alarm_r_limit[chan->channel] = val; + reg = BD79124_GET_HIGH_LIMIT_REG(chan->channel); + } else if (dir == IIO_EV_DIR_FALLING) { + data->alarm_f_limit[chan->channel] = val; + reg = BD79124_GET_LOW_LIMIT_REG(chan->channel); + } else { + return -EINVAL; + } + /* + * We don't want to enable the alarm if it is not enabled or + * if it is suppressed. In that case skip writing to the + * register. + */ + if (!(data->alarm_monitored[chan->channel] & BIT(dir)) || + data->alarm_suppressed[chan->channel] & BIT(dir)) + return 0; + + return bd79124_write_int_to_reg(data, reg, val); + } + case IIO_EV_INFO_HYSTERESIS: + reg = BD79124_GET_HYSTERESIS_REG(chan->channel); + val >>= 3; + + return regmap_update_bits(data->map, reg, BD79124_MSK_HYSTERESIS, + val); + default: + return -EINVAL; + } +} + +static int bd79124_single_chan_seq(struct bd79124_data *data, int chan, unsigned int *old) +{ + int ret; + + ret = regmap_clear_bits(data->map, BD79124_REG_SEQ_CFG, + BD79124_MSK_SEQ_START); + if (ret) + return ret; + + /* + * It may be we have some channels monitored for alarms so we want to + * cache the old config and return it when the single channel + * measurement has been completed. + */ + ret = regmap_read(data->map, BD79124_REG_AUTO_CHANNELS, old); + if (ret) + return ret; + + ret = regmap_write(data->map, BD79124_REG_AUTO_CHANNELS, BIT(chan)); + if (ret) + return ret; + + /* Restart the sequencer */ + return regmap_set_bits(data->map, BD79124_REG_SEQ_CFG, + BD79124_MSK_SEQ_START); +} + +static int bd79124_single_chan_seq_end(struct bd79124_data *data, unsigned int old) +{ + int ret; + + ret = regmap_clear_bits(data->map, BD79124_REG_SEQ_CFG, + BD79124_MSK_SEQ_START); + if (ret) + return ret; + + ret = regmap_write(data->map, BD79124_REG_AUTO_CHANNELS, old); + if (ret) + return ret; + + return regmap_set_bits(data->map, BD79124_REG_SEQ_CFG, + BD79124_MSK_SEQ_START); +} + +static int bd79124_read_raw(struct iio_dev *iio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long m) +{ + struct bd79124_data *data = iio_priv(iio_dev); + int ret; + + if (chan->channel >= BD79124_MAX_NUM_CHANNELS) + return -EINVAL; + + switch (m) { + case IIO_CHAN_INFO_RAW: + { + unsigned int old_chan_cfg, regval; + int tmp; + + guard(mutex)(&data->mutex); + + /* + * Start the automatic conversion. This is needed here if no + * events have been enabled. + */ + regval = FIELD_PREP(BD79124_MSK_CONV_MODE, + BD79124_CONV_MODE_AUTO); + ret = regmap_update_bits(data->map, BD79124_REG_OPMODE_CFG, + BD79124_MSK_CONV_MODE, regval); + if (ret) + return ret; + + ret = bd79124_single_chan_seq(data, chan->channel, &old_chan_cfg); + if (ret) + return ret; + + /* The maximum conversion time is 6 uS. */ + udelay(6); + + ret = bd79124_read_reg_to_int(data, + BD79124_GET_RECENT_RES_REG(chan->channel), val); + /* + * Return the old chan config even if data reading failed in + * order to re-enable the event monitoring. + */ + tmp = bd79124_single_chan_seq_end(data, old_chan_cfg); + if (tmp) + dev_err(data->dev, + "Failed to return config. Alarms may be disabled\n"); + + if (ret) + return ret; + + return IIO_VAL_INT; + } + case IIO_CHAN_INFO_SCALE: + *val = data->vmax / 1000; + *val2 = BD79124_ADC_BITS; + return IIO_VAL_FRACTIONAL_LOG2; + default: + return -EINVAL; + } +} + +static const struct iio_info bd79124_info = { + .read_raw = bd79124_read_raw, + .read_event_config = &bd79124_read_event_config, + .write_event_config = &bd79124_write_event_config, + .read_event_value = &bd79124_read_event_value, + .write_event_value = &bd79124_write_event_value, +}; + +static void bd79124_re_enable_lo(struct bd79124_data *data, unsigned int channel) +{ + int ret, evbit = BIT(IIO_EV_DIR_FALLING); + + /* + * We should not re-enable the event if user has disabled it while + * rate-limiting was enabled. + */ + if (!(data->alarm_suppressed[channel] & evbit)) + return; + + data->alarm_suppressed[channel] &= ~evbit; + + if (!(data->alarm_monitored[channel] & evbit)) + return; + + ret = bd79124_write_int_to_reg(data, BD79124_GET_LOW_LIMIT_REG(channel), + data->alarm_f_limit[channel]); + if (ret) + dev_warn(data->dev, "Low limit enabling failed for channel%d\n", + channel); +} + +static void bd79124_re_enable_hi(struct bd79124_data *data, unsigned int channel) +{ + int ret, evbit = BIT(IIO_EV_DIR_RISING); + + /* + * We should not re-enable the event if user has disabled it while + * rate-limiting was enabled. + */ + if (!(data->alarm_suppressed[channel] & evbit)) + return; + + data->alarm_suppressed[channel] &= ~evbit; + + if (!(data->alarm_monitored[channel] & evbit)) + return; + + ret = bd79124_write_int_to_reg(data, BD79124_GET_HIGH_LIMIT_REG(channel), + data->alarm_r_limit[channel]); + if (ret) + dev_warn(data->dev, "High limit enabling failed for channel%d\n", + channel); +} + +static void bd79124_alm_enable_worker(struct work_struct *work) +{ + int i; + struct bd79124_data *data = container_of(work, struct bd79124_data, + alm_enable_work.work); + + /* Take the mutex so there is no race with user disabling the alarm */ + guard(mutex)(&data->mutex); + for (i = 0; i < BD79124_MAX_NUM_CHANNELS; i++) { + bd79124_re_enable_hi(data, i); + bd79124_re_enable_lo(data, i); + } +} + +static int __bd79124_event_ratelimit(struct bd79124_data *data, int reg, + unsigned int limit) +{ + int ret; + + if (limit > BD79124_HIGH_LIMIT_MAX) + return -EINVAL; + + ret = bd79124_write_int_to_reg(data, reg, limit); + if (ret) + return ret; + + /* + * We use 1 sec 'grace period'. At the moment I see no reason to make + * this user configurable. We need an ABI for this if configuration is + * needed. + */ + schedule_delayed_work(&data->alm_enable_work, msecs_to_jiffies(1000)); + + return 0; +} + +static int bd79124_event_ratelimit_hi(struct bd79124_data *data, + unsigned int channel) +{ + guard(mutex)(&data->mutex); + data->alarm_suppressed[channel] |= BIT(IIO_EV_DIR_RISING); + + return __bd79124_event_ratelimit(data, + BD79124_GET_HIGH_LIMIT_REG(channel), + BD79124_HIGH_LIMIT_MAX); +} + +static int bd79124_event_ratelimit_lo(struct bd79124_data *data, + unsigned int channel) +{ + guard(mutex)(&data->mutex); + data->alarm_suppressed[channel] |= BIT(IIO_EV_DIR_FALLING); + + return __bd79124_event_ratelimit(data, + BD79124_GET_LOW_LIMIT_REG(channel), + BD79124_LOW_LIMIT_MIN); +} + +static irqreturn_t bd79124_event_handler(int irq, void *priv) +{ + unsigned int i_hi, i_lo; + int i, ret; + struct iio_dev *iio_dev = priv; + struct bd79124_data *data = iio_priv(iio_dev); + + /* + * Return IRQ_NONE if bailing-out without acking. This allows the IRQ + * subsystem to disable the offending IRQ line if we get a hardware + * problem. This behaviour has saved my poor bottom a few times in the + * past as, instead of getting unusably unresponsive, the system has + * spilled out the magic words "...nobody cared". + */ + ret = regmap_read(data->map, BD79124_REG_EVENT_FLAG_HI, &i_hi); + if (ret) + return IRQ_NONE; + + ret = regmap_read(data->map, BD79124_REG_EVENT_FLAG_LO, &i_lo); + if (ret) + return IRQ_NONE; + + if (!i_lo && !i_hi) + return IRQ_NONE; + + for (i = 0; i < BD79124_MAX_NUM_CHANNELS; i++) { + u64 ecode; + + if (BIT(i) & i_hi) { + ecode = IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i, + IIO_EV_TYPE_THRESH, + IIO_EV_DIR_RISING); + + iio_push_event(iio_dev, ecode, data->timestamp); + /* + * The BD79124 keeps the IRQ asserted for as long as + * the voltage exceeds the threshold. It causes the IRQ + * to keep firing. + * + * Disable the event for the channel and schedule the + * re-enabling the event later to prevent storm of + * events. + */ + ret = bd79124_event_ratelimit_hi(data, i); + if (ret) + return IRQ_NONE; + } + if (BIT(i) & i_lo) { + ecode = IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i, + IIO_EV_TYPE_THRESH, + IIO_EV_DIR_FALLING); + + iio_push_event(iio_dev, ecode, data->timestamp); + ret = bd79124_event_ratelimit_lo(data, i); + if (ret) + return IRQ_NONE; + } + } + + ret = regmap_write(data->map, BD79124_REG_EVENT_FLAG_HI, i_hi); + if (ret) + return IRQ_NONE; + + ret = regmap_write(data->map, BD79124_REG_EVENT_FLAG_LO, i_lo); + if (ret) + return IRQ_NONE; + + return IRQ_HANDLED; +} + +static irqreturn_t bd79124_irq_handler(int irq, void *priv) +{ + struct iio_dev *iio_dev = priv; + struct bd79124_data *data = iio_priv(iio_dev); + + data->timestamp = iio_get_time_ns(iio_dev); + + return IRQ_WAKE_THREAD; +} + +static int bd79124_chan_init(struct bd79124_data *data, int channel) +{ + int ret; + + ret = regmap_write(data->map, BD79124_GET_HIGH_LIMIT_REG(channel), + BD79124_HIGH_LIMIT_MAX); + if (ret) + return ret; + + return regmap_write(data->map, BD79124_GET_LOW_LIMIT_REG(channel), + BD79124_LOW_LIMIT_MIN); +} + +static int bd79124_get_gpio_pins(const struct iio_chan_spec *cs, int num_channels) +{ + int i, gpio_channels; + + /* + * Let's initialize the mux config to say that all 8 channels are + * GPIOs. Then we can just loop through the iio_chan_spec and clear the + * bits for found ADC channels. + */ + gpio_channels = GENMASK(7, 0); + for (i = 0; i < num_channels; i++) + gpio_channels &= ~BIT(cs[i].channel); + + return gpio_channels; +} + +static int bd79124_hw_init(struct bd79124_data *data) +{ + unsigned int regval; + int ret, i; + + for (i = 0; i < BD79124_MAX_NUM_CHANNELS; i++) { + ret = bd79124_chan_init(data, i); + if (ret) + return ret; + data->alarm_r_limit[i] = BD79124_HIGH_LIMIT_MAX; + } + /* Stop auto sequencer */ + ret = regmap_clear_bits(data->map, BD79124_REG_SEQ_CFG, + BD79124_MSK_SEQ_START); + if (ret) + return ret; + + /* Enable writing the measured values to the regsters */ + ret = regmap_set_bits(data->map, BD79124_REG_GEN_CFG, + BD79124_MSK_STATS_EN); + if (ret) + return ret; + + /* Set no channels to be auto-measured */ + ret = regmap_write(data->map, BD79124_REG_AUTO_CHANNELS, 0x0); + if (ret) + return ret; + + /* Set no channels to be manually measured */ + ret = regmap_write(data->map, BD79124_REG_MANUAL_CHANNELS, 0x0); + if (ret) + return ret; + + regval = FIELD_PREP(BD79124_MSK_AUTO_INTERVAL, BD79124_INTERVAL_750_US); + ret = regmap_update_bits(data->map, BD79124_REG_OPMODE_CFG, + BD79124_MSK_AUTO_INTERVAL, regval); + if (ret) + return ret; + + /* Sequencer mode to auto */ + ret = regmap_set_bits(data->map, BD79124_REG_SEQ_CFG, + BD79124_MSK_SEQ_SEQ); + if (ret) + return ret; + + /* Don't start the measurement */ + regval = FIELD_PREP(BD79124_MSK_CONV_MODE, BD79124_CONV_MODE_MANSEQ); + return regmap_update_bits(data->map, BD79124_REG_OPMODE_CFG, + BD79124_MSK_CONV_MODE, regval); +} + +static int bd79124_probe(struct i2c_client *i2c) +{ + struct bd79124_data *data; + struct iio_dev *iio_dev; + const struct iio_chan_spec *template; + struct iio_chan_spec *cs; + struct device *dev = &i2c->dev; + unsigned int gpio_pins; + int ret; + + iio_dev = devm_iio_device_alloc(dev, sizeof(*data)); + if (!iio_dev) + return -ENOMEM; + + data = iio_priv(iio_dev); + data->dev = dev; + data->map = devm_regmap_init_i2c(i2c, &bd79124_regmap); + if (IS_ERR(data->map)) + return dev_err_probe(dev, PTR_ERR(data->map), + "Failed to initialize Regmap\n"); + + ret = devm_regulator_get_enable_read_voltage(dev, "vdd"); + if (ret < 0) + return dev_err_probe(dev, ret, "Failed to get the Vdd\n"); + + data->vmax = ret; + + ret = devm_regulator_get_enable(dev, "iovdd"); + if (ret < 0) + return dev_err_probe(dev, ret, "Failed to enable I/O voltage\n"); + + ret = devm_delayed_work_autocancel(dev, &data->alm_enable_work, + bd79124_alm_enable_worker); + if (ret) + return ret; + + if (i2c->irq) { + template = &bd79124_chan_template; + } else { + template = &bd79124_chan_template_noirq; + dev_dbg(dev, "No IRQ found, events disabled\n"); + } + + ret = devm_mutex_init(dev, &data->mutex); + if (ret) + return ret; + + ret = devm_iio_adc_device_alloc_chaninfo_se(dev, template, + BD79124_MAX_NUM_CHANNELS - 1, &cs); + if (ret < 0) { + /* Register all pins as GPOs if there are no ADC channels */ + if (ret == -ENOENT) + goto register_gpios; + return ret; + } + iio_dev->channels = cs; + iio_dev->num_channels = ret; + iio_dev->info = &bd79124_info; + iio_dev->name = "bd79124"; + iio_dev->modes = INDIO_DIRECT_MODE; + + ret = bd79124_hw_init(data); + if (ret) + return ret; + + if (i2c->irq > 0) { + ret = devm_request_threaded_irq(dev, i2c->irq, + bd79124_irq_handler, &bd79124_event_handler, + IRQF_ONESHOT, "adc-thresh-alert", iio_dev); + if (ret) + return dev_err_probe(data->dev, ret, + "Failed to register IRQ\n"); + } + + ret = devm_iio_device_register(data->dev, iio_dev); + if (ret) + return dev_err_probe(data->dev, ret, "Failed to register ADC\n"); + +register_gpios: + gpio_pins = bd79124_get_gpio_pins(iio_dev->channels, + iio_dev->num_channels); + + /* + * The mux should default to "all ADCs", but better to not trust it. + * Thus we do set the mux even when we have only ADCs and no GPOs. + */ + ret = regmap_write(data->map, BD79124_REG_PINCFG, gpio_pins); + if (ret) + return ret; + + /* No GPOs if all channels are reserved for ADC, so we're done. */ + if (!gpio_pins) + return 0; + + data->gpio_valid_mask = gpio_pins; + data->gc = bd79124gpo_chip; + data->gc.parent = dev; + + return devm_gpiochip_add_data(dev, &data->gc, data); +} + +static const struct of_device_id bd79124_of_match[] = { + { .compatible = "rohm,bd79124" }, + { } +}; +MODULE_DEVICE_TABLE(of, bd79124_of_match); + +static const struct i2c_device_id bd79124_id[] = { + { "bd79124" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, bd79124_id); + +static struct i2c_driver bd79124_driver = { + .driver = { + .name = "bd79124", + .of_match_table = bd79124_of_match, + }, + .probe = bd79124_probe, + .id_table = bd79124_id, +}; +module_i2c_driver(bd79124_driver); + +MODULE_AUTHOR("Matti Vaittinen <mazziesaccount@gmail.com>"); +MODULE_DESCRIPTION("Driver for ROHM BD79124 ADC"); +MODULE_LICENSE("GPL"); +MODULE_IMPORT_NS("IIO_DRIVER"); |