diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c index 7ed31399a875..9d58ced7371d 100644 --- a/drivers/iio/adc/ad7124.c +++ b/drivers/iio/adc/ad7124.c @@ -111,6 +111,8 @@ #define AD7124_FILTER_SINGLE_CYCLE BIT(16) #define AD7124_FILTER_FS GENMASK(10, 0) +#define AD7124_CFG_SLOT_UNASSIGNED ~0U + #define AD7124_MAX_CONFIGS 8 #define AD7124_MAX_CHANNELS 16 @@ -176,14 +178,13 @@ enum ad7124_filter_type { }; struct ad7124_channel_config { - bool live; unsigned int cfg_slot; unsigned int requested_odr; unsigned int requested_odr_micro; /* * Following fields are used to compare for equality. If you * make adaptations in it, you most likely also have to adapt - * ad7124_find_similar_live_cfg(), too. + * ad7124_config_equal(), too. */ struct_group(config_props, enum ad7124_ref_sel refsel; @@ -215,14 +216,13 @@ struct ad7124_state { unsigned int adc_control; unsigned int num_channels; struct mutex cfgs_lock; /* lock for configs access */ - unsigned long cfg_slots_status; /* bitmap with slot status (1 means it is used) */ + u8 cfg_slot_use_count[AD7124_MAX_CONFIGS]; /* * Stores the power-on reset value for the GAIN(x) registers which are * needed for measurements at gain 1 (i.e. CONFIG(x).PGA == 0) */ unsigned int gain_default; - DECLARE_KFIFO(live_cfgs_fifo, struct ad7124_channel_config *, AD7124_MAX_CONFIGS); bool enable_single_cycle; }; @@ -367,9 +367,6 @@ static void ad7124_set_channel_odr(struct ad7124_state *st, unsigned int channel cfg->requested_odr_micro * factor / MICRO; odr_sel_bits = clamp(DIV_ROUND_CLOSEST(fclk, divisor), 1, 2047); - if (odr_sel_bits != st->channels[channel].cfg.odr_sel_bits) - st->channels[channel].cfg.live = false; - st->channels[channel].cfg.odr_sel_bits = odr_sel_bits; } @@ -404,61 +401,6 @@ static int ad7124_get_3db_filter_factor(struct ad7124_state *st, } } -static struct ad7124_channel_config *ad7124_find_similar_live_cfg(struct ad7124_state *st, - struct ad7124_channel_config *cfg) -{ - struct ad7124_channel_config *cfg_aux; - int i; - - /* - * This is just to make sure that the comparison is adapted after - * struct ad7124_channel_config was changed. - */ - static_assert(sizeof_field(struct ad7124_channel_config, config_props) == - sizeof(struct { - enum ad7124_ref_sel refsel; - bool bipolar; - bool buf_positive; - bool buf_negative; - unsigned int vref_mv; - unsigned int pga_bits; - unsigned int odr_sel_bits; - enum ad7124_filter_type filter_type; - unsigned int calibration_offset; - unsigned int calibration_gain; - })); - - for (i = 0; i < st->num_channels; i++) { - cfg_aux = &st->channels[i].cfg; - - if (cfg_aux->live && - cfg->refsel == cfg_aux->refsel && - cfg->bipolar == cfg_aux->bipolar && - cfg->buf_positive == cfg_aux->buf_positive && - cfg->buf_negative == cfg_aux->buf_negative && - cfg->vref_mv == cfg_aux->vref_mv && - cfg->pga_bits == cfg_aux->pga_bits && - cfg->odr_sel_bits == cfg_aux->odr_sel_bits && - cfg->filter_type == cfg_aux->filter_type && - cfg->calibration_offset == cfg_aux->calibration_offset && - cfg->calibration_gain == cfg_aux->calibration_gain) - return cfg_aux; - } - - return NULL; -} - -static int ad7124_find_free_config_slot(struct ad7124_state *st) -{ - unsigned int free_cfg_slot; - - free_cfg_slot = find_first_zero_bit(&st->cfg_slots_status, AD7124_MAX_CONFIGS); - if (free_cfg_slot == AD7124_MAX_CONFIGS) - return -1; - - return free_cfg_slot; -} - /* Only called during probe, so dev_err_probe() can be used */ static int ad7124_init_config_vref(struct ad7124_state *st, struct ad7124_channel_config *cfg) { @@ -487,6 +429,21 @@ static int ad7124_init_config_vref(struct ad7124_state *st, struct ad7124_channe } } +static bool ad7124_config_equal(struct ad7124_channel_config *a, + struct ad7124_channel_config *b) +{ + return a->refsel == b->refsel && + a->bipolar == b->bipolar && + a->buf_positive == b->buf_positive && + a->buf_negative == b->buf_negative && + a->vref_mv == b->vref_mv && + a->pga_bits == b->pga_bits && + a->odr_sel_bits == b->odr_sel_bits && + a->filter_type == b->filter_type && + a->calibration_offset == b->calibration_offset && + a->calibration_gain == b->calibration_gain; +} + static int ad7124_write_config(struct ad7124_state *st, struct ad7124_channel_config *cfg, unsigned int cfg_slot) { @@ -495,13 +452,13 @@ static int ad7124_write_config(struct ad7124_state *st, struct ad7124_channel_co unsigned int post = 0; int ret; - cfg->cfg_slot = cfg_slot; - - ret = ad_sd_write_reg(&st->sd, AD7124_OFFSET(cfg->cfg_slot), 3, cfg->calibration_offset); + ret = ad_sd_write_reg(&st->sd, AD7124_OFFSET(cfg_slot), 3, + cfg->calibration_offset); if (ret) return ret; - ret = ad_sd_write_reg(&st->sd, AD7124_GAIN(cfg->cfg_slot), 3, cfg->calibration_gain); + ret = ad_sd_write_reg(&st->sd, AD7124_GAIN(cfg_slot), 3, + cfg->calibration_gain); if (ret) return ret; @@ -511,7 +468,7 @@ static int ad7124_write_config(struct ad7124_state *st, struct ad7124_channel_co (cfg->buf_negative ? AD7124_CONFIG_AIN_BUFM : 0) | FIELD_PREP(AD7124_CONFIG_PGA, cfg->pga_bits); - ret = ad_sd_write_reg(&st->sd, AD7124_CONFIG(cfg->cfg_slot), 2, val); + ret = ad_sd_write_reg(&st->sd, AD7124_CONFIG(cfg_slot), 2, val); if (ret < 0) return ret; @@ -564,7 +521,7 @@ static int ad7124_write_config(struct ad7124_state *st, struct ad7124_channel_co * was requested. It may only be disabled through debugfs for testing * purposes. */ - return ad_sd_write_reg(&st->sd, AD7124_FILTER(cfg->cfg_slot), 3, + return ad_sd_write_reg(&st->sd, AD7124_FILTER(cfg_slot), 3, FIELD_PREP(AD7124_FILTER_FILTER, filter) | FIELD_PREP(AD7124_FILTER_REJ60, rej60) | FIELD_PREP(AD7124_FILTER_POST_FILTER, post) | @@ -573,83 +530,86 @@ static int ad7124_write_config(struct ad7124_state *st, struct ad7124_channel_co FIELD_PREP(AD7124_FILTER_FS, cfg->odr_sel_bits)); } -static struct ad7124_channel_config *ad7124_pop_config(struct ad7124_state *st) +/** + * ad7124_request_config_slot() - Request a config slot for a given config + * @st: Driver instance + * @channel: Channel to request a slot for + * + * Tries to find a matching config already in use, otherwise finds a free + * slot. If this function returns successfully, the use count for the slot is + * increased and the slot number is stored in cfg->cfg_slot. + * + * The slot must be released again with ad7124_release_config_slot() when no + * longer needed. + * + * Returns: 0 if a slot was successfully assigned, -EUSERS if no slot is + * available or other error if SPI communication fails. + */ +static int ad7124_request_config_slot(struct ad7124_state *st, u8 channel) { - struct ad7124_channel_config *lru_cfg; - struct ad7124_channel_config *cfg; - int ret; - int i; + unsigned int other, slot; + int last_used_slot = -1; - /* - * Pop least recently used config from the fifo - * in order to make room for the new one - */ - ret = kfifo_get(&st->live_cfgs_fifo, &lru_cfg); - if (ret <= 0) - return NULL; + /* Find another channel with a matching config, if any. */ + for (other = 0; other < st->num_channels; other++) { + if (other == channel) + continue; - lru_cfg->live = false; + if (st->channels[other].cfg.cfg_slot == AD7124_CFG_SLOT_UNASSIGNED) + continue; - /* mark slot as free */ - assign_bit(lru_cfg->cfg_slot, &st->cfg_slots_status, 0); + last_used_slot = max_t(int, last_used_slot, + st->channels[other].cfg.cfg_slot); - /* invalidate all other configs that pointed to this one */ - for (i = 0; i < st->num_channels; i++) { - cfg = &st->channels[i].cfg; + if (!ad7124_config_equal(&st->channels[other].cfg, + &st->channels[channel].cfg)) + continue; - if (cfg->cfg_slot == lru_cfg->cfg_slot) - cfg->live = false; + /* Found a match, re-use that slot. */ + slot = st->channels[other].cfg.cfg_slot; + st->cfg_slot_use_count[slot]++; + st->channels[channel].cfg.cfg_slot = slot; + + return 0; } - return lru_cfg; + /* No match, use next free slot. */ + slot = last_used_slot + 1; + if (slot >= AD7124_MAX_CONFIGS) + return -EUSERS; + + st->cfg_slot_use_count[slot]++; + st->channels[channel].cfg.cfg_slot = slot; + + return ad7124_write_config(st, &st->channels[channel].cfg, slot); } -static int ad7124_push_config(struct ad7124_state *st, struct ad7124_channel_config *cfg) +static void ad7124_release_config_slot(struct ad7124_state *st, u8 channel) { - struct ad7124_channel_config *lru_cfg; - int free_cfg_slot; + unsigned int slot = st->channels[channel].cfg.cfg_slot; - free_cfg_slot = ad7124_find_free_config_slot(st); - if (free_cfg_slot >= 0) { - /* push the new config in configs queue */ - kfifo_put(&st->live_cfgs_fifo, cfg); - } else { - /* pop one config to make room for the new one */ - lru_cfg = ad7124_pop_config(st); - if (!lru_cfg) - return -EINVAL; + /* + * All of these conditions can happen at probe when all channels are + * disabled. Otherwise, they should not happen normally. + */ + if (channel >= st->num_channels || slot == AD7124_CFG_SLOT_UNASSIGNED || + st->cfg_slot_use_count[slot] == 0) + return; - /* push the new config in configs queue */ - free_cfg_slot = lru_cfg->cfg_slot; - kfifo_put(&st->live_cfgs_fifo, cfg); - } - - /* mark slot as used */ - assign_bit(free_cfg_slot, &st->cfg_slots_status, 1); - - return ad7124_write_config(st, cfg, free_cfg_slot); + st->cfg_slot_use_count[slot]--; + st->channels[channel].cfg.cfg_slot = AD7124_CFG_SLOT_UNASSIGNED; } static int ad7124_prepare_read(struct ad7124_state *st, int address) { struct ad7124_channel_config *cfg = &st->channels[address].cfg; - struct ad7124_channel_config *live_cfg; + int ret; - /* - * Before doing any reads assign the channel a configuration. - * Check if channel's config is on the device - */ - if (!cfg->live) { - /* check if config matches another one */ - live_cfg = ad7124_find_similar_live_cfg(st, cfg); - if (!live_cfg) - ad7124_push_config(st, cfg); - else - cfg->cfg_slot = live_cfg->cfg_slot; - } + ret = ad7124_request_config_slot(st, address); + if (ret) + return ret; /* point channel to the config slot and enable */ - cfg->live = true; return ad_sd_write_reg(&st->sd, AD7124_CHANNEL(address), 2, st->channels[address].ain | FIELD_PREP(AD7124_CHANNEL_SETUP, cfg->cfg_slot) | @@ -692,6 +652,8 @@ static int ad7124_disable_one(struct ad_sigma_delta *sd, unsigned int chan) { struct ad7124_state *st = container_of(sd, struct ad7124_state, sd); + ad7124_release_config_slot(st, chan); + /* The relevant thing here is that AD7124_CHANNEL_ENABLE is cleared. */ return ad_sd_write_reg(&st->sd, AD7124_CHANNEL(chan), 2, 0); } @@ -913,9 +875,6 @@ static int ad7124_write_raw(struct iio_dev *indio_dev, gain = DIV_ROUND_CLOSEST(res, val2); res = ad7124_find_closest_match(ad7124_gain, ARRAY_SIZE(ad7124_gain), gain); - if (st->channels[chan->address].cfg.pga_bits != res) - st->channels[chan->address].cfg.live = false; - st->channels[chan->address].cfg.pga_bits = res; return 0; default: @@ -1058,7 +1017,11 @@ static int ad7124_syscalib_locked(struct ad7124_state *st, const struct iio_chan if (ret < 0) return ret; - ret = ad_sd_read_reg(&st->sd, AD7124_OFFSET(ch->cfg.cfg_slot), 3, + /* + * Making the assumption that a single conversion will always + * use configuration slot 0 for the OFFSET/GAIN registers. + */ + ret = ad_sd_read_reg(&st->sd, AD7124_OFFSET(0), 3, &ch->cfg.calibration_offset); if (ret < 0) return ret; @@ -1073,7 +1036,7 @@ static int ad7124_syscalib_locked(struct ad7124_state *st, const struct iio_chan if (ret < 0) return ret; - ret = ad_sd_read_reg(&st->sd, AD7124_GAIN(ch->cfg.cfg_slot), 3, + ret = ad_sd_read_reg(&st->sd, AD7124_GAIN(0), 3, &ch->cfg.calibration_gain); if (ret < 0) return ret; @@ -1164,7 +1127,6 @@ static int ad7124_set_filter_type_attr(struct iio_dev *dev, guard(mutex)(&st->cfgs_lock); - cfg->live = false; cfg->filter_type = value; ad7124_set_channel_odr(st, chan->address); @@ -1484,7 +1446,6 @@ static int ad7124_setup(struct ad7124_state *st) if (ret) return ret; - INIT_KFIFO(st->live_cfgs_fifo); for (i = 0; i < st->num_channels; i++) { struct ad7124_channel_config *cfg = &st->channels[i].cfg; @@ -1492,6 +1453,8 @@ static int ad7124_setup(struct ad7124_state *st) if (ret < 0) return ret; + cfg->cfg_slot = AD7124_CFG_SLOT_UNASSIGNED; + /* Default filter type on the ADC after reset. */ cfg->filter_type = AD7124_FILTER_TYPE_SINC4; @@ -1551,7 +1514,7 @@ static int __ad7124_calibrate_all(struct ad7124_state *st, struct iio_dev *indio * ad_sigma_delta_set_channel() -> ad7124_set_channel() * -> ad7124_prepare_read(). */ - ret = ad_sd_read_reg(&st->sd, AD7124_GAIN(st->channels[i].cfg.cfg_slot), 3, + ret = ad_sd_read_reg(&st->sd, AD7124_GAIN(0), 3, &st->channels[i].cfg.calibration_gain); if (ret < 0) return ret; @@ -1561,7 +1524,11 @@ static int __ad7124_calibrate_all(struct ad7124_state *st, struct iio_dev *indio if (ret < 0) return ret; - ret = ad_sd_read_reg(&st->sd, AD7124_OFFSET(st->channels[i].cfg.cfg_slot), 3, + /* + * Making the assumption that a single conversion will always + * use configuration slot 0 for the OFFSET/GAIN registers. + */ + ret = ad_sd_read_reg(&st->sd, AD7124_OFFSET(0), 3, &st->channels[i].cfg.calibration_offset); if (ret < 0) return ret;