diff options
Diffstat (limited to 'drivers/iio/adc/ti-tsc2046.c')
| -rw-r--r-- | drivers/iio/adc/ti-tsc2046.c | 269 |
1 files changed, 202 insertions, 67 deletions
diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c index e8fc4d01f30b..55b35570ad8b 100644 --- a/drivers/iio/adc/ti-tsc2046.c +++ b/drivers/iio/adc/ti-tsc2046.c @@ -82,6 +82,11 @@ #define TI_TSC2046_DATA_12BIT GENMASK(14, 3) #define TI_TSC2046_MAX_CHAN 8 +#define TI_TSC2046_MIN_POLL_CNT 3 +#define TI_TSC2046_EXT_POLL_CNT 3 +#define TI_TSC2046_POLL_CNT \ + (TI_TSC2046_MIN_POLL_CNT + TI_TSC2046_EXT_POLL_CNT) +#define TI_TSC2046_INT_VREF 2500 /* Represents a HW sample */ struct tsc2046_adc_atom { @@ -123,14 +128,23 @@ struct tsc2046_adc_ch_cfg { unsigned int oversampling_ratio; }; +enum tsc2046_state { + TSC2046_STATE_SHUTDOWN, + TSC2046_STATE_STANDBY, + TSC2046_STATE_POLL, + TSC2046_STATE_POLL_IRQ_DISABLE, + TSC2046_STATE_ENABLE_IRQ, +}; + struct tsc2046_adc_priv { struct spi_device *spi; const struct tsc2046_adc_dcfg *dcfg; struct iio_trigger *trig; struct hrtimer trig_timer; - spinlock_t trig_lock; - unsigned int trig_more_count; + enum tsc2046_state state; + int poll_cnt; + spinlock_t state_lock; struct spi_transfer xfer; struct spi_message msg; @@ -153,9 +167,6 @@ struct tsc2046_adc_priv { struct tsc2046_adc_atom *rx; struct tsc2046_adc_atom *tx; - struct tsc2046_adc_atom *rx_one; - struct tsc2046_adc_atom *tx_one; - unsigned int count; unsigned int groups; u32 effective_speed_hz; @@ -171,6 +182,8 @@ struct tsc2046_adc_priv { .type = IIO_VOLTAGE, \ .indexed = 1, \ .channel = index, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ .datasheet_name = "#name", \ .scan_index = index, \ .scan_type = { \ @@ -234,6 +247,14 @@ static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx, else pd = 0; + switch (ch_idx) { + case TI_TSC2046_ADDR_TEMP1: + case TI_TSC2046_ADDR_AUX: + case TI_TSC2046_ADDR_VBAT: + case TI_TSC2046_ADDR_TEMP0: + pd |= TI_TSC2046_SER | TI_TSC2046_PD1_VREF_ON; + } + return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd; } @@ -245,16 +266,50 @@ static u16 tsc2046_adc_get_value(struct tsc2046_adc_atom *buf) static int tsc2046_adc_read_one(struct tsc2046_adc_priv *priv, int ch_idx, u32 *effective_speed_hz) { + struct tsc2046_adc_ch_cfg *ch = &priv->ch_cfg[ch_idx]; + struct tsc2046_adc_atom *rx_buf, *tx_buf; + unsigned int val, val_normalized = 0; + int ret, i, count_skip = 0, max_count; struct spi_transfer xfer; struct spi_message msg; - int ret; + u8 cmd; + + if (!effective_speed_hz) { + count_skip = tsc2046_adc_time_to_count(priv, ch->settling_time_us); + max_count = count_skip + ch->oversampling_ratio; + } else { + max_count = 1; + } + + if (sizeof(*tx_buf) * max_count > PAGE_SIZE) + return -ENOSPC; + + tx_buf = kcalloc(max_count, sizeof(*tx_buf), GFP_KERNEL); + if (!tx_buf) + return -ENOMEM; + + rx_buf = kcalloc(max_count, sizeof(*rx_buf), GFP_KERNEL); + if (!rx_buf) { + ret = -ENOMEM; + goto free_tx; + } + + /* + * Do not enable automatic power down on working samples. Otherwise the + * plates will never be completely charged. + */ + cmd = tsc2046_adc_get_cmd(priv, ch_idx, true); + + for (i = 0; i < max_count - 1; i++) + tx_buf[i].cmd = cmd; + + /* automatically power down on last sample */ + tx_buf[i].cmd = tsc2046_adc_get_cmd(priv, ch_idx, false); memset(&xfer, 0, sizeof(xfer)); - priv->tx_one->cmd = tsc2046_adc_get_cmd(priv, ch_idx, false); - priv->tx_one->data = 0; - xfer.tx_buf = priv->tx_one; - xfer.rx_buf = priv->rx_one; - xfer.len = sizeof(*priv->tx_one); + xfer.tx_buf = tx_buf; + xfer.rx_buf = rx_buf; + xfer.len = sizeof(*tx_buf) * max_count; spi_message_init_with_transfers(&msg, &xfer, 1); /* @@ -265,13 +320,25 @@ static int tsc2046_adc_read_one(struct tsc2046_adc_priv *priv, int ch_idx, if (ret) { dev_err_ratelimited(&priv->spi->dev, "SPI transfer failed %pe\n", ERR_PTR(ret)); - return ret; + goto free_bufs; } if (effective_speed_hz) *effective_speed_hz = xfer.effective_speed_hz; - return tsc2046_adc_get_value(priv->rx_one); + for (i = 0; i < max_count - count_skip; i++) { + val = tsc2046_adc_get_value(&rx_buf[count_skip + i]); + val_normalized += val; + } + + ret = DIV_ROUND_UP(val_normalized, max_count - count_skip); + +free_bufs: + kfree(rx_buf); +free_tx: + kfree(tx_buf); + + return ret; } static size_t tsc2046_adc_group_set_layout(struct tsc2046_adc_priv *priv, @@ -378,6 +445,37 @@ static irqreturn_t tsc2046_adc_trigger_handler(int irq, void *p) return IRQ_HANDLED; } +static int tsc2046_adc_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long m) +{ + struct tsc2046_adc_priv *priv = iio_priv(indio_dev); + int ret; + + switch (m) { + case IIO_CHAN_INFO_RAW: + ret = tsc2046_adc_read_one(priv, chan->channel, NULL); + if (ret < 0) + return ret; + + *val = ret; + + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + /* + * Note: the TSC2046 has internal voltage divider on the VBAT + * line. This divider can be influenced by external divider. + * So, it is better to use external voltage-divider driver + * instead, which is calculating complete chain. + */ + *val = TI_TSC2046_INT_VREF; + *val2 = chan->scan_type.realbits; + return IIO_VAL_FRACTIONAL_LOG2; + } + + return -EINVAL; +} + static int tsc2046_adc_update_scan_mode(struct iio_dev *indio_dev, const unsigned long *active_scan_mask) { @@ -408,24 +506,67 @@ static int tsc2046_adc_update_scan_mode(struct iio_dev *indio_dev, } static const struct iio_info tsc2046_adc_info = { + .read_raw = tsc2046_adc_read_raw, .update_scan_mode = tsc2046_adc_update_scan_mode, }; -static enum hrtimer_restart tsc2046_adc_trig_more(struct hrtimer *hrtimer) +static enum hrtimer_restart tsc2046_adc_timer(struct hrtimer *hrtimer) { struct tsc2046_adc_priv *priv = container_of(hrtimer, struct tsc2046_adc_priv, trig_timer); unsigned long flags; - spin_lock_irqsave(&priv->trig_lock, flags); - - disable_irq_nosync(priv->spi->irq); - - priv->trig_more_count++; - iio_trigger_poll(priv->trig); + /* + * This state machine should address following challenges : + * - the interrupt source is based on level shifter attached to the X + * channel of ADC. It will change the state every time we switch + * between channels. So, we need to disable IRQ if we do + * iio_trigger_poll(). + * - we should do iio_trigger_poll() at some reduced sample rate + * - we should still trigger for some amount of time after last + * interrupt with enabled IRQ was processed. + */ - spin_unlock_irqrestore(&priv->trig_lock, flags); + spin_lock_irqsave(&priv->state_lock, flags); + switch (priv->state) { + case TSC2046_STATE_ENABLE_IRQ: + if (priv->poll_cnt < TI_TSC2046_POLL_CNT) { + priv->poll_cnt++; + hrtimer_start(&priv->trig_timer, + ns_to_ktime(priv->scan_interval_us * + NSEC_PER_USEC), + HRTIMER_MODE_REL_SOFT); + + if (priv->poll_cnt >= TI_TSC2046_MIN_POLL_CNT) { + priv->state = TSC2046_STATE_POLL_IRQ_DISABLE; + enable_irq(priv->spi->irq); + } else { + priv->state = TSC2046_STATE_POLL; + } + } else { + priv->state = TSC2046_STATE_STANDBY; + enable_irq(priv->spi->irq); + } + break; + case TSC2046_STATE_POLL_IRQ_DISABLE: + disable_irq_nosync(priv->spi->irq); + fallthrough; + case TSC2046_STATE_POLL: + priv->state = TSC2046_STATE_ENABLE_IRQ; + /* iio_trigger_poll() starts hrtimer */ + iio_trigger_poll(priv->trig); + break; + case TSC2046_STATE_SHUTDOWN: + break; + case TSC2046_STATE_STANDBY: + fallthrough; + default: + dev_warn(&priv->spi->dev, "Got unexpected state: %i\n", + priv->state); + break; + } + spin_unlock_irqrestore(&priv->state_lock, flags); return HRTIMER_NORESTART; } @@ -434,16 +575,20 @@ static irqreturn_t tsc2046_adc_irq(int irq, void *dev_id) { struct iio_dev *indio_dev = dev_id; struct tsc2046_adc_priv *priv = iio_priv(indio_dev); - - spin_lock(&priv->trig_lock); + unsigned long flags; hrtimer_try_to_cancel(&priv->trig_timer); - priv->trig_more_count = 0; - disable_irq_nosync(priv->spi->irq); - iio_trigger_poll(priv->trig); + spin_lock_irqsave(&priv->state_lock, flags); + if (priv->state != TSC2046_STATE_SHUTDOWN) { + priv->state = TSC2046_STATE_ENABLE_IRQ; + priv->poll_cnt = 0; - spin_unlock(&priv->trig_lock); + /* iio_trigger_poll() starts hrtimer */ + disable_irq_nosync(priv->spi->irq); + iio_trigger_poll(priv->trig); + } + spin_unlock_irqrestore(&priv->state_lock, flags); return IRQ_HANDLED; } @@ -452,49 +597,42 @@ static void tsc2046_adc_reenable_trigger(struct iio_trigger *trig) { struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig); struct tsc2046_adc_priv *priv = iio_priv(indio_dev); - unsigned long flags; - int delta; + ktime_t tim; /* * We can sample it as fast as we can, but usually we do not need so * many samples. Reduce the sample rate for default (touchscreen) use * case. - * Currently we do not need a highly precise sample rate. It is enough - * to have calculated numbers. - */ - delta = priv->scan_interval_us - priv->time_per_scan_us; - if (delta > 0) - fsleep(delta); - - spin_lock_irqsave(&priv->trig_lock, flags); - - /* - * We need to trigger at least one extra sample to detect state - * difference on ADC side. */ - if (!priv->trig_more_count) { - int timeout_ms = DIV_ROUND_UP(priv->scan_interval_us, - USEC_PER_MSEC); - - hrtimer_start(&priv->trig_timer, ms_to_ktime(timeout_ms), - HRTIMER_MODE_REL_SOFT); - } - - enable_irq(priv->spi->irq); - - spin_unlock_irqrestore(&priv->trig_lock, flags); + tim = ns_to_ktime((priv->scan_interval_us - priv->time_per_scan_us) * + NSEC_PER_USEC); + hrtimer_start(&priv->trig_timer, tim, HRTIMER_MODE_REL_SOFT); } static int tsc2046_adc_set_trigger_state(struct iio_trigger *trig, bool enable) { struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig); struct tsc2046_adc_priv *priv = iio_priv(indio_dev); + unsigned long flags; if (enable) { - enable_irq(priv->spi->irq); + spin_lock_irqsave(&priv->state_lock, flags); + if (priv->state == TSC2046_STATE_SHUTDOWN) { + priv->state = TSC2046_STATE_STANDBY; + enable_irq(priv->spi->irq); + } + spin_unlock_irqrestore(&priv->state_lock, flags); } else { - disable_irq(priv->spi->irq); - hrtimer_try_to_cancel(&priv->trig_timer); + spin_lock_irqsave(&priv->state_lock, flags); + + if (priv->state == TSC2046_STATE_STANDBY || + priv->state == TSC2046_STATE_POLL_IRQ_DISABLE) + disable_irq_nosync(priv->spi->irq); + + priv->state = TSC2046_STATE_SHUTDOWN; + spin_unlock_irqrestore(&priv->state_lock, flags); + + hrtimer_cancel(&priv->trig_timer); } return 0; @@ -511,16 +649,6 @@ static int tsc2046_adc_setup_spi_msg(struct tsc2046_adc_priv *priv) size_t size; int ret; - priv->tx_one = devm_kzalloc(&priv->spi->dev, sizeof(*priv->tx_one), - GFP_KERNEL); - if (!priv->tx_one) - return -ENOMEM; - - priv->rx_one = devm_kzalloc(&priv->spi->dev, sizeof(*priv->rx_one), - GFP_KERNEL); - if (!priv->rx_one) - return -ENOMEM; - /* * Make dummy read to set initial power state and get real SPI clock * freq. It seems to be not important which channel is used for this @@ -551,6 +679,12 @@ static int tsc2046_adc_setup_spi_msg(struct tsc2046_adc_priv *priv) for (ch_idx = 0; ch_idx < ARRAY_SIZE(priv->l); ch_idx++) size += tsc2046_adc_group_set_layout(priv, ch_idx, ch_idx); + if (size > PAGE_SIZE) { + dev_err(&priv->spi->dev, + "Calculated scan buffer is too big. Try to reduce spi-max-frequency, settling-time-us or oversampling-ratio\n"); + return -ENOSPC; + } + priv->tx = devm_kzalloc(&priv->spi->dev, size, GFP_KERNEL); if (!priv->tx) return -ENOMEM; @@ -668,10 +802,11 @@ static int tsc2046_adc_probe(struct spi_device *spi) iio_trigger_set_drvdata(trig, indio_dev); trig->ops = &tsc2046_adc_trigger_ops; - spin_lock_init(&priv->trig_lock); + spin_lock_init(&priv->state_lock); + priv->state = TSC2046_STATE_SHUTDOWN; hrtimer_init(&priv->trig_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT); - priv->trig_timer.function = tsc2046_adc_trig_more; + priv->trig_timer.function = tsc2046_adc_timer; ret = devm_iio_trigger_register(dev, trig); if (ret) { |