diff options
Diffstat (limited to 'drivers/iio/adc/ti-tsc2046.c')
| -rw-r--r-- | drivers/iio/adc/ti-tsc2046.c | 912 |
1 files changed, 912 insertions, 0 deletions
diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c new file mode 100644 index 0000000000..1bbb51a668 --- /dev/null +++ b/drivers/iio/adc/ti-tsc2046.c @@ -0,0 +1,912 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Texas Instruments TSC2046 SPI ADC driver + * + * Copyright (c) 2021 Oleksij Rempel <kernel@pengutronix.de>, Pengutronix + */ + +#include <linux/bitfield.h> +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> +#include <linux/spi/spi.h> +#include <linux/units.h> + +#include <asm/unaligned.h> + +#include <linux/iio/buffer.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> +#include <linux/iio/trigger.h> + +/* + * The PENIRQ of TSC2046 controller is implemented as level shifter attached to + * the X+ line. If voltage of the X+ line reaches a specific level the IRQ will + * be activated or deactivated. + * To make this kind of IRQ reusable as trigger following additions were + * implemented: + * - rate limiting: + * For typical touchscreen use case, we need to trigger about each 10ms. + * - hrtimer: + * Continue triggering at least once after the IRQ was deactivated. Then + * deactivate this trigger to stop sampling in order to reduce power + * consumption. + */ + +#define TI_TSC2046_NAME "tsc2046" + +/* This driver doesn't aim at the peak continuous sample rate */ +#define TI_TSC2046_MAX_SAMPLE_RATE 125000 +#define TI_TSC2046_SAMPLE_BITS \ + BITS_PER_TYPE(struct tsc2046_adc_atom) +#define TI_TSC2046_MAX_CLK_FREQ \ + (TI_TSC2046_MAX_SAMPLE_RATE * TI_TSC2046_SAMPLE_BITS) + +#define TI_TSC2046_SAMPLE_INTERVAL_US 10000 + +#define TI_TSC2046_START BIT(7) +#define TI_TSC2046_ADDR GENMASK(6, 4) +#define TI_TSC2046_ADDR_TEMP1 7 +#define TI_TSC2046_ADDR_AUX 6 +#define TI_TSC2046_ADDR_X 5 +#define TI_TSC2046_ADDR_Z2 4 +#define TI_TSC2046_ADDR_Z1 3 +#define TI_TSC2046_ADDR_VBAT 2 +#define TI_TSC2046_ADDR_Y 1 +#define TI_TSC2046_ADDR_TEMP0 0 + +/* + * The mode bit sets the resolution of the ADC. With this bit low, the next + * conversion has 12-bit resolution, whereas with this bit high, the next + * conversion has 8-bit resolution. This driver is optimized for 12-bit mode. + * So, for this driver, this bit should stay zero. + */ +#define TI_TSC2046_8BIT_MODE BIT(3) + +/* + * SER/DFR - The SER/DFR bit controls the reference mode, either single-ended + * (high) or differential (low). + */ +#define TI_TSC2046_SER BIT(2) + +/* + * If VREF_ON and ADC_ON are both zero, then the chip operates in + * auto-wake/suspend mode. In most case this bits should stay zero. + */ +#define TI_TSC2046_PD1_VREF_ON BIT(1) +#define TI_TSC2046_PD0_ADC_ON BIT(0) + +/* + * All supported devices can do 8 or 12bit resolution. This driver + * supports only 12bit mode, here we have a 16bit data transfer, where + * the MSB and the 3 LSB are 0. + */ +#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 { + /* + * Command transmitted to the controller. This field is empty on the RX + * buffer. + */ + u8 cmd; + /* + * Data received from the controller. This field is empty for the TX + * buffer + */ + __be16 data; +} __packed; + +/* Layout of atomic buffers within big buffer */ +struct tsc2046_adc_group_layout { + /* Group offset within the SPI RX buffer */ + unsigned int offset; + /* + * Amount of tsc2046_adc_atom structs within the same command gathered + * within same group. + */ + unsigned int count; + /* + * Settling samples (tsc2046_adc_atom structs) which should be skipped + * before good samples will start. + */ + unsigned int skip; +}; + +struct tsc2046_adc_dcfg { + const struct iio_chan_spec *channels; + unsigned int num_channels; +}; + +struct tsc2046_adc_ch_cfg { + unsigned int settling_time_us; + 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 regulator *vref_reg; + + struct iio_trigger *trig; + struct hrtimer trig_timer; + enum tsc2046_state state; + int poll_cnt; + spinlock_t state_lock; + + struct spi_transfer xfer; + struct spi_message msg; + + struct { + /* Scan data for each channel */ + u16 data[TI_TSC2046_MAX_CHAN]; + /* Timestamp */ + s64 ts __aligned(8); + } scan_buf; + + /* + * Lock to protect the layout and the SPI transfer buffer. + * tsc2046_adc_group_layout can be changed within update_scan_mode(), + * in this case the l[] and tx/rx buffer will be out of sync to each + * other. + */ + struct mutex slock; + struct tsc2046_adc_group_layout l[TI_TSC2046_MAX_CHAN]; + struct tsc2046_adc_atom *rx; + struct tsc2046_adc_atom *tx; + + unsigned int count; + unsigned int groups; + u32 effective_speed_hz; + u32 scan_interval_us; + u32 time_per_scan_us; + u32 time_per_bit_ns; + unsigned int vref_mv; + + struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN]; +}; + +#define TI_TSC2046_V_CHAN(index, bits, name) \ +{ \ + .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 = { \ + .sign = 'u', \ + .realbits = bits, \ + .storagebits = 16, \ + .endianness = IIO_CPU, \ + }, \ +} + +#define DECLARE_TI_TSC2046_8_CHANNELS(name, bits) \ +const struct iio_chan_spec name ## _channels[] = { \ + TI_TSC2046_V_CHAN(0, bits, TEMP0), \ + TI_TSC2046_V_CHAN(1, bits, Y), \ + TI_TSC2046_V_CHAN(2, bits, VBAT), \ + TI_TSC2046_V_CHAN(3, bits, Z1), \ + TI_TSC2046_V_CHAN(4, bits, Z2), \ + TI_TSC2046_V_CHAN(5, bits, X), \ + TI_TSC2046_V_CHAN(6, bits, AUX), \ + TI_TSC2046_V_CHAN(7, bits, TEMP1), \ + IIO_CHAN_SOFT_TIMESTAMP(8), \ +} + +static DECLARE_TI_TSC2046_8_CHANNELS(tsc2046_adc, 12); + +static const struct tsc2046_adc_dcfg tsc2046_adc_dcfg_tsc2046e = { + .channels = tsc2046_adc_channels, + .num_channels = ARRAY_SIZE(tsc2046_adc_channels), +}; + +/* + * Convert time to a number of samples which can be transferred within this + * time. + */ +static unsigned int tsc2046_adc_time_to_count(struct tsc2046_adc_priv *priv, + unsigned long time) +{ + unsigned int bit_count, sample_count; + + bit_count = DIV_ROUND_UP(time * NSEC_PER_USEC, priv->time_per_bit_ns); + sample_count = DIV_ROUND_UP(bit_count, TI_TSC2046_SAMPLE_BITS); + + dev_dbg(&priv->spi->dev, "Effective speed %u, time per bit: %u, count bits: %u, count samples: %u\n", + priv->effective_speed_hz, priv->time_per_bit_ns, + bit_count, sample_count); + + return sample_count; +} + +static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx, + bool keep_power) +{ + u32 pd; + + /* + * if PD bits are 0, controller will automatically disable ADC, VREF and + * enable IRQ. + */ + if (keep_power) + pd = TI_TSC2046_PD0_ADC_ON; + 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; + if (!priv->vref_reg) + pd |= TI_TSC2046_PD1_VREF_ON; + } + + return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd; +} + +static u16 tsc2046_adc_get_value(struct tsc2046_adc_atom *buf) +{ + return FIELD_GET(TI_TSC2046_DATA_12BIT, get_unaligned_be16(&buf->data)); +} + +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; + 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)); + 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); + + /* + * We aren't using spi_write_then_read() because we need to be able + * to get hold of the effective_speed_hz from the xfer + */ + ret = spi_sync(priv->spi, &msg); + if (ret) { + dev_err_ratelimited(&priv->spi->dev, "SPI transfer failed %pe\n", + ERR_PTR(ret)); + goto free_bufs; + } + + if (effective_speed_hz) + *effective_speed_hz = xfer.effective_speed_hz; + + 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, + unsigned int group, + unsigned int ch_idx) +{ + struct tsc2046_adc_ch_cfg *ch = &priv->ch_cfg[ch_idx]; + struct tsc2046_adc_group_layout *cur; + unsigned int max_count, count_skip; + unsigned int offset = 0; + + if (group) + offset = priv->l[group - 1].offset + priv->l[group - 1].count; + + count_skip = tsc2046_adc_time_to_count(priv, ch->settling_time_us); + max_count = count_skip + ch->oversampling_ratio; + + cur = &priv->l[group]; + cur->offset = offset; + cur->count = max_count; + cur->skip = count_skip; + + return sizeof(*priv->tx) * max_count; +} + +static void tsc2046_adc_group_set_cmd(struct tsc2046_adc_priv *priv, + unsigned int group, int ch_idx) +{ + struct tsc2046_adc_group_layout *l = &priv->l[group]; + unsigned int i; + u8 cmd; + + /* + * 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 < l->count - 1; i++) + priv->tx[l->offset + i].cmd = cmd; + + /* automatically power down on last sample */ + priv->tx[l->offset + i].cmd = tsc2046_adc_get_cmd(priv, ch_idx, false); +} + +static u16 tsc2046_adc_get_val(struct tsc2046_adc_priv *priv, int group) +{ + struct tsc2046_adc_group_layout *l; + unsigned int val, val_normalized = 0; + int valid_count, i; + + l = &priv->l[group]; + valid_count = l->count - l->skip; + + for (i = 0; i < valid_count; i++) { + val = tsc2046_adc_get_value(&priv->rx[l->offset + l->skip + i]); + val_normalized += val; + } + + return DIV_ROUND_UP(val_normalized, valid_count); +} + +static int tsc2046_adc_scan(struct iio_dev *indio_dev) +{ + struct tsc2046_adc_priv *priv = iio_priv(indio_dev); + struct device *dev = &priv->spi->dev; + int group; + int ret; + + ret = spi_sync(priv->spi, &priv->msg); + if (ret < 0) { + dev_err_ratelimited(dev, "SPI transfer failed: %pe\n", ERR_PTR(ret)); + return ret; + } + + for (group = 0; group < priv->groups; group++) + priv->scan_buf.data[group] = tsc2046_adc_get_val(priv, group); + + ret = iio_push_to_buffers_with_timestamp(indio_dev, &priv->scan_buf, + iio_get_time_ns(indio_dev)); + /* If the consumer is kfifo, we may get a EBUSY here - ignore it. */ + if (ret < 0 && ret != -EBUSY) { + dev_err_ratelimited(dev, "Failed to push scan buffer %pe\n", + ERR_PTR(ret)); + + return ret; + } + + return 0; +} + +static irqreturn_t tsc2046_adc_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct tsc2046_adc_priv *priv = iio_priv(indio_dev); + + mutex_lock(&priv->slock); + tsc2046_adc_scan(indio_dev); + mutex_unlock(&priv->slock); + + iio_trigger_notify_done(indio_dev->trig); + + 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 = priv->vref_mv; + *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) +{ + struct tsc2046_adc_priv *priv = iio_priv(indio_dev); + unsigned int ch_idx, group = 0; + size_t size; + + mutex_lock(&priv->slock); + + size = 0; + for_each_set_bit(ch_idx, active_scan_mask, ARRAY_SIZE(priv->l)) { + size += tsc2046_adc_group_set_layout(priv, group, ch_idx); + tsc2046_adc_group_set_cmd(priv, group, ch_idx); + group++; + } + + priv->groups = group; + priv->xfer.len = size; + priv->time_per_scan_us = size * 8 * priv->time_per_bit_ns / NSEC_PER_USEC; + + if (priv->scan_interval_us < priv->time_per_scan_us) + dev_warn(&priv->spi->dev, "The scan interval (%d) is less then calculated scan time (%d)\n", + priv->scan_interval_us, priv->time_per_scan_us); + + mutex_unlock(&priv->slock); + + return 0; +} + +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_timer(struct hrtimer *hrtimer) +{ + struct tsc2046_adc_priv *priv = container_of(hrtimer, + struct tsc2046_adc_priv, + trig_timer); + unsigned long flags; + + /* + * 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_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; +} + +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); + unsigned long flags; + + hrtimer_try_to_cancel(&priv->trig_timer); + + spin_lock_irqsave(&priv->state_lock, flags); + if (priv->state != TSC2046_STATE_SHUTDOWN) { + priv->state = TSC2046_STATE_ENABLE_IRQ; + priv->poll_cnt = 0; + + /* 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; +} + +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); + 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. + */ + 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) { + 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 { + 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; +} + +static const struct iio_trigger_ops tsc2046_adc_trigger_ops = { + .set_trigger_state = tsc2046_adc_set_trigger_state, + .reenable = tsc2046_adc_reenable_trigger, +}; + +static int tsc2046_adc_setup_spi_msg(struct tsc2046_adc_priv *priv) +{ + unsigned int ch_idx; + size_t size; + int ret; + + /* + * 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 + * case. + */ + ret = tsc2046_adc_read_one(priv, TI_TSC2046_ADDR_TEMP0, + &priv->effective_speed_hz); + if (ret < 0) + return ret; + + /* + * In case SPI controller do not report effective_speed_hz, use + * configure value and hope it will match. + */ + if (!priv->effective_speed_hz) + priv->effective_speed_hz = priv->spi->max_speed_hz; + + + priv->scan_interval_us = TI_TSC2046_SAMPLE_INTERVAL_US; + priv->time_per_bit_ns = DIV_ROUND_UP(NSEC_PER_SEC, + priv->effective_speed_hz); + + /* + * Calculate and allocate maximal size buffer if all channels are + * enabled. + */ + size = 0; + 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; + + priv->rx = devm_kzalloc(&priv->spi->dev, size, GFP_KERNEL); + if (!priv->rx) + return -ENOMEM; + + priv->xfer.tx_buf = priv->tx; + priv->xfer.rx_buf = priv->rx; + priv->xfer.len = size; + spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1); + + return 0; +} + +static void tsc2046_adc_parse_fwnode(struct tsc2046_adc_priv *priv) +{ + struct fwnode_handle *child; + struct device *dev = &priv->spi->dev; + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(priv->ch_cfg); i++) { + priv->ch_cfg[i].settling_time_us = 1; + priv->ch_cfg[i].oversampling_ratio = 1; + } + + device_for_each_child_node(dev, child) { + u32 stl, overs, reg; + int ret; + + ret = fwnode_property_read_u32(child, "reg", ®); + if (ret) { + dev_err(dev, "invalid reg on %pfw, err: %pe\n", child, + ERR_PTR(ret)); + continue; + } + + if (reg >= ARRAY_SIZE(priv->ch_cfg)) { + dev_err(dev, "%pfw: Unsupported reg value: %i, max supported is: %zu.\n", + child, reg, ARRAY_SIZE(priv->ch_cfg)); + continue; + } + + ret = fwnode_property_read_u32(child, "settling-time-us", &stl); + if (!ret) + priv->ch_cfg[reg].settling_time_us = stl; + + ret = fwnode_property_read_u32(child, "oversampling-ratio", + &overs); + if (!ret) + priv->ch_cfg[reg].oversampling_ratio = overs; + } +} + +static void tsc2046_adc_regulator_disable(void *data) +{ + struct tsc2046_adc_priv *priv = data; + + regulator_disable(priv->vref_reg); +} + +static int tsc2046_adc_configure_regulator(struct tsc2046_adc_priv *priv) +{ + struct device *dev = &priv->spi->dev; + int ret; + + priv->vref_reg = devm_regulator_get_optional(dev, "vref"); + if (IS_ERR(priv->vref_reg)) { + /* If regulator exists but can't be get, return an error */ + if (PTR_ERR(priv->vref_reg) != -ENODEV) + return PTR_ERR(priv->vref_reg); + priv->vref_reg = NULL; + } + if (!priv->vref_reg) { + /* Use internal reference */ + priv->vref_mv = TI_TSC2046_INT_VREF; + return 0; + } + + ret = regulator_enable(priv->vref_reg); + if (ret) + return ret; + + ret = devm_add_action_or_reset(dev, tsc2046_adc_regulator_disable, + priv); + if (ret) + return ret; + + ret = regulator_get_voltage(priv->vref_reg); + if (ret < 0) + return ret; + + priv->vref_mv = ret / MILLI; + + return 0; +} + +static int tsc2046_adc_probe(struct spi_device *spi) +{ + const struct tsc2046_adc_dcfg *dcfg; + struct device *dev = &spi->dev; + struct tsc2046_adc_priv *priv; + struct iio_dev *indio_dev; + struct iio_trigger *trig; + int ret; + + if (spi->max_speed_hz > TI_TSC2046_MAX_CLK_FREQ) { + dev_err(dev, "SPI max_speed_hz is too high: %d Hz. Max supported freq is %zu Hz\n", + spi->max_speed_hz, TI_TSC2046_MAX_CLK_FREQ); + return -EINVAL; + } + + dcfg = device_get_match_data(dev); + if (!dcfg) { + const struct spi_device_id *id = spi_get_device_id(spi); + + dcfg = (const struct tsc2046_adc_dcfg *)id->driver_data; + } + if (!dcfg) + return -EINVAL; + + spi->bits_per_word = 8; + spi->mode &= ~SPI_MODE_X_MASK; + spi->mode |= SPI_MODE_0; + ret = spi_setup(spi); + if (ret < 0) + return dev_err_probe(dev, ret, "Error in SPI setup\n"); + + indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); + if (!indio_dev) + return -ENOMEM; + + priv = iio_priv(indio_dev); + priv->dcfg = dcfg; + + priv->spi = spi; + + indio_dev->name = TI_TSC2046_NAME; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = dcfg->channels; + indio_dev->num_channels = dcfg->num_channels; + indio_dev->info = &tsc2046_adc_info; + + ret = tsc2046_adc_configure_regulator(priv); + if (ret) + return ret; + + tsc2046_adc_parse_fwnode(priv); + + ret = tsc2046_adc_setup_spi_msg(priv); + if (ret) + return ret; + + mutex_init(&priv->slock); + + ret = devm_request_irq(dev, spi->irq, &tsc2046_adc_irq, + IRQF_NO_AUTOEN, indio_dev->name, indio_dev); + if (ret) + return ret; + + trig = devm_iio_trigger_alloc(dev, "touchscreen-%s", indio_dev->name); + if (!trig) + return -ENOMEM; + + priv->trig = trig; + iio_trigger_set_drvdata(trig, indio_dev); + trig->ops = &tsc2046_adc_trigger_ops; + + 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_timer; + + ret = devm_iio_trigger_register(dev, trig); + if (ret) { + dev_err(dev, "failed to register trigger\n"); + return ret; + } + + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL, + &tsc2046_adc_trigger_handler, NULL); + if (ret) { + dev_err(dev, "Failed to setup triggered buffer\n"); + return ret; + } + + /* set default trigger */ + indio_dev->trig = iio_trigger_get(priv->trig); + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct of_device_id ads7950_of_table[] = { + { .compatible = "ti,tsc2046e-adc", .data = &tsc2046_adc_dcfg_tsc2046e }, + { } +}; +MODULE_DEVICE_TABLE(of, ads7950_of_table); + +static const struct spi_device_id tsc2046_adc_spi_ids[] = { + { "tsc2046e-adc", (unsigned long)&tsc2046_adc_dcfg_tsc2046e }, + { } +}; +MODULE_DEVICE_TABLE(spi, tsc2046_adc_spi_ids); + +static struct spi_driver tsc2046_adc_driver = { + .driver = { + .name = "tsc2046", + .of_match_table = ads7950_of_table, + }, + .id_table = tsc2046_adc_spi_ids, + .probe = tsc2046_adc_probe, +}; +module_spi_driver(tsc2046_adc_driver); + +MODULE_AUTHOR("Oleksij Rempel <kernel@pengutronix.de>"); +MODULE_DESCRIPTION("TI TSC2046 ADC"); +MODULE_LICENSE("GPL v2"); |