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Message-ID: <CAHp75VdRQ2DpW=NJJkgHmGPb5r4_eLx8COQHukR6y6w-w=He=w@mail.gmail.com>
Date: Fri, 12 Mar 2021 17:32:45 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Oleksij Rempel <o.rempel@...gutronix.de>
Cc: Rob Herring <robh+dt@...nel.org>,
Jonathan Cameron <jic23@...nel.org>,
devicetree <devicetree@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Pengutronix Kernel Team <kernel@...gutronix.de>,
David Jander <david@...tonic.nl>,
Robin van der Gracht <robin@...tonic.nl>,
linux-iio <linux-iio@...r.kernel.org>,
Lars-Peter Clausen <lars@...afoo.de>,
Peter Meerwald-Stadler <pmeerw@...erw.net>,
Dmitry Torokhov <dmitry.torokhov@...il.com>
Subject: Re: [PATCH v2 3/3] iio: adc: add ADC driver for the TI TSC2046 controller
On Fri, Mar 12, 2021 at 12:57 PM Oleksij Rempel <o.rempel@...gutronix.de> wrote:
>
> Basically the TI TSC2046 touchscreen controller is 8 channel ADC optimized for
> the touchscreen use case. By implementing it as IIO ADC device, we can
as an IIO
> make use of resistive-adc-touch and iio-hwmon drivers.
>
> So far, this driver was tested with custom version of resistive-adc-touch driver,
with a custom
> since it need to be extended to make use of Z1 and Z2 channels. The X/Y
needs
> are working without additional changes.
With above typos fixed, although there is still room for bikeshedding
and small improvements
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
Thanks!
> Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>
> ---
> MAINTAINERS | 8 +
> drivers/iio/adc/Kconfig | 12 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/ti-tsc2046.c | 713 +++++++++++++++++++++++++++++++++++
> 4 files changed, 734 insertions(+)
> create mode 100644 drivers/iio/adc/ti-tsc2046.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 3fea1a934b32..2d33c6442a55 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -17852,6 +17852,14 @@ S: Supported
> F: Documentation/devicetree/bindings/net/nfc/trf7970a.txt
> F: drivers/nfc/trf7970a.c
>
> +TI TSC2046 ADC DRIVER
> +M: Oleksij Rempel <o.rempel@...gutronix.de>
> +R: kernel@...gutronix.de
> +L: linux-iio@...r.kernel.org
> +S: Maintained
> +F: Documentation/devicetree/bindings/iio/adc/ti,tsc2046.yaml
> +F: drivers/iio/adc/ti-tsc2046.c
> +
> TI TWL4030 SERIES SOC CODEC DRIVER
> M: Peter Ujfalusi <peter.ujfalusi@...il.com>
> L: alsa-devel@...a-project.org (moderated for non-subscribers)
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 15587a1bc80d..6ad6f04dfd20 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -1175,6 +1175,18 @@ config TI_TLC4541
> This driver can also be built as a module. If so, the module will be
> called ti-tlc4541.
>
> +config TI_TSC2046
> + tristate "Texas Instruments TSC2046 ADC driver"
> + depends on SPI
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> + help
> + Say yes here to build support for ADC functionality of Texas
> + Instruments TSC2046 touch screen controller.
> +
> + This driver can also be built as a module. If so, the module will be
> + called ti-tsc2046.
> +
> config TWL4030_MADC
> tristate "TWL4030 MADC (Monitoring A/D Converter)"
> depends on TWL4030_CORE
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 5fca90ada0ec..440e18ac6780 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -105,6 +105,7 @@ obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
> obj-$(CONFIG_TI_ADS124S08) += ti-ads124s08.o
> obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
> obj-$(CONFIG_TI_TLC4541) += ti-tlc4541.o
> +obj-$(CONFIG_TI_TSC2046) += ti-tsc2046.o
> obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
> obj-$(CONFIG_TWL6030_GPADC) += twl6030-gpadc.o
> obj-$(CONFIG_VF610_ADC) += vf610_adc.o
> diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c
> new file mode 100644
> index 000000000000..7c3ae9181164
> --- /dev/null
> +++ b/drivers/iio/adc/ti-tsc2046.c
> @@ -0,0 +1,713 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Texas Instruments TSC2046 SPI ADC driver
> + *
> + * Copyright (c) 2021 Oleksij Rempel <kernel@...gutronix.de>, Pengutronix
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/spi/spi.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>
> +
> +#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 (8 /*cmd*/ + 16 /*sample*/)
> +#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)
> +
> +#define TI_TSC2046_MAX_CHAN 8
> +
> +/* Represents a HW sample */
> +struct tsc2046_adc_atom {
> + /*
> + * Command transmitted to the controller. This filed is empty on the RX
> + * buffer.
> + */
> + u8 cmd;
> + /*
> + * Data received from the controller. This filed is empty for the TX
> + * buffer
> + */
> + __be16 data;
> +} __packed;
> +
> +struct tsc2046_adc_scan_buf {
> + /* Scan data for each channel */
> + u16 data[TI_TSC2046_MAX_CHAN];
> + /* Timestamp */
> + s64 ts __aligned(8);
> +};
> +
> +/* 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 average_samples;
> +};
> +
> +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;
> + atomic_t trig_more_count;
> +
> + struct spi_transfer xfer;
> + struct spi_message msg;
> +
> + struct tsc2046_adc_scan_buf 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;
> +
> + struct tsc2046_adc_atom *rx_one;
> + struct tsc2046_adc_atom *tx_one;
> +
> + unsigned int count;
> + unsigned int groups;
> + u32 effective_speed_hz;
> + u32 scan_interval_us;
> + u32 time_per_scan_us;
> + u32 time_per_bit_ns;
> +
> + 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, \
> + .address = index, \
> + .datasheet_name = "#name", \
> + .scan_index = index, \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = bits, \
> + .storagebits = 16, \
> + .shift = 0, \
> + .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;
> +
> + return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd;
> +}
> +
> +static u16 tsc2046_adc_get_value(struct tsc2046_adc_atom *buf)
> +{
> + /* Last 3 bits on the wire are empty */
> + return get_unaligned_be16(&buf->data) >> 3;
> +}
> +
> +static int tsc2046_adc_read_one(struct tsc2046_adc_priv *priv, int ch_idx,
> + u32 *effective_speed_hz)
> +{
> + struct spi_transfer xfer;
> + struct spi_message msg;
> + int ret;
> +
> + 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);
> + spi_message_init(&msg);
> + spi_message_add_tail(&xfer, &msg);
> +
> + ret = spi_sync(priv->spi, &msg);
> + if (ret) {
> + dev_err_ratelimited(&priv->spi->dev, "SPI transfer filed %pe\n",
> + ERR_PTR(ret));
> + return ret;
> + }
> +
> + if (effective_speed_hz)
> + *effective_speed_hz = xfer.effective_speed_hz;
> +
> + return tsc2046_adc_get_value(priv->rx_one);
> +}
> +
> +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 *prev, *cur;
> + unsigned int max_count, count_skip;
> + unsigned int offset = 0;
> +
> +
> + if (group) {
> + prev = &priv->l[group - 1];
> + offset = prev->offset + prev->count;
> + }
> +
> + cur = &priv->l[group];
> +
> + count_skip = tsc2046_adc_time_to_count(priv, ch->settling_time_us);
> + max_count = count_skip + ch->average_samples;
> +
> + 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 filed: %pe\n",
> + ERR_PTR(ret));
> + return ret;
> + }
> +
> + for (group = 0; group < priv->groups; group++) {
> + u16 val = tsc2046_adc_get_val(priv, group);
> +
> + priv->scan_buf.data[group] = val;
> + }
> +
> + ret = iio_push_to_buffers_with_timestamp(indio_dev, &priv->scan_buf,
> + iio_get_time_ns(indio_dev));
> + /*
> + * If there's no consumer (or consumer is kfifo), may get a EBUSY here
> + * - ignore it.
> + */
> + if (ret < 0 && ret != -EBUSY) {
> + dev_err_ratelimited(dev, "Filed 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_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 = 0;
> +
> + mutex_lock(&priv->slock);
> +
> + for_each_set_bit(ch_idx, active_scan_mask, indio_dev->num_channels) {
> + 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) < 0)
> + 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 = {
> + .update_scan_mode = tsc2046_adc_update_scan_mode,
> +};
> +
> +static enum hrtimer_restart tsc2046_adc_trig_more(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);
> +
> + atomic_inc(&priv->trig_more_count);
> + iio_trigger_poll(priv->trig);
> +
> + spin_unlock_irqrestore(&priv->trig_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);
> +
> +
> + spin_lock(&priv->trig_lock);
> +
> + hrtimer_try_to_cancel(&priv->trig_timer);
> +
> + atomic_set(&priv->trig_more_count, 0);
> + disable_irq_nosync(priv->spi->irq);
> + iio_trigger_poll(priv->trig);
> +
> + spin_unlock(&priv->trig_lock);
> +
> + 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);
> + unsigned long flags;
> + int delta;
> +
> + /*
> + * 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 (atomic_read(&priv->trig_more_count) == 0) {
> + 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);
> +}
> +
> +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);
> +
> + if (enable) {
> + enable_irq(priv->spi->irq);
> + } else {
> + disable_irq(priv->spi->irq);
> + hrtimer_try_to_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 = 0;
> + 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
> + * 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.
> + */
> + for (ch_idx = 0; ch_idx < priv->dcfg->num_channels; ch_idx++)
> + size += tsc2046_adc_group_set_layout(priv, ch_idx, ch_idx);
> +
> + 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;
> +
> + spi_message_init(&priv->msg);
> + priv->msg.context = priv;
> +
> + priv->xfer.tx_buf = priv->tx;
> + priv->xfer.rx_buf = priv->rx;
> + priv->xfer.len = size;
> + spi_message_add_tail(&priv->xfer, &priv->msg);
> +
> + return 0;
> +}
> +
> +static void tsc2046_adc_parse_fwnode(struct tsc2046_adc_priv *priv)
> +{
> + struct fwnode_handle *child;
> + struct device *dev = &priv->spi->dev;
> +
> + device_for_each_child_node(dev, child) {
> + u32 stl, aver, 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: %i.\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, "average-samples", &aver);
> + if (!ret)
> + priv->ch_cfg[reg].average_samples = aver;
> + }
> +}
> +
> +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;
> + const char *name;
> + 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 %d Hz\n",
> + spi->max_speed_hz, TI_TSC2046_MAX_CLK_FREQ);
> + return -EINVAL;
> + }
> +
> + dcfg = device_get_match_data(dev);
> + 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;
> +
> + spi_set_drvdata(spi, indio_dev);
> +
> + priv->spi = spi;
> +
> + name = devm_kasprintf(dev, GFP_KERNEL, "%s-%s",
> + TI_TSC2046_NAME, dev_name(dev));
> +
> + indio_dev->name = name;
> + indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED;
> + indio_dev->channels = dcfg->channels;
> + indio_dev->num_channels = dcfg->num_channels;
> + indio_dev->info = &tsc2046_adc_info;
> +
> + tsc2046_adc_parse_fwnode(priv);
> +
> + ret = tsc2046_adc_setup_spi_msg(priv);
> + if (ret)
> + return ret;
> +
> + mutex_init(&priv->slock);
> +
> + /* TODO: remove IRQ_NOAUTOEN after needed patches are mainline */
> + irq_set_status_flags(spi->irq, IRQ_NOAUTOEN);
> + ret = devm_request_irq(dev, spi->irq, &tsc2046_adc_irq,
> + 0, name, indio_dev);
> + if (ret)
> + return ret;
> +
> + trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name,
> + indio_dev->id);
> + if (!trig)
> + return -ENOMEM;
> +
> + priv->trig = trig;
> + trig->dev.parent = indio_dev->dev.parent;
> + iio_trigger_set_drvdata(trig, indio_dev);
> + trig->ops = &tsc2046_adc_trigger_ops;
> +
> + spin_lock_init(&priv->trig_lock);
> + hrtimer_init(&priv->trig_timer, CLOCK_MONOTONIC,
> + HRTIMER_MODE_REL_SOFT);
> + priv->trig_timer.function = tsc2046_adc_trig_more;
> +
> + 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);
> +
> + ret = devm_iio_device_register(dev, indio_dev);
> + if (ret) {
> + dev_err(dev, "Failed to register iio device\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +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 struct spi_driver tsc2046_adc_driver = {
> + .driver = {
> + .name = "tsc2046",
> + .of_match_table = ads7950_of_table,
> + },
> + .probe = tsc2046_adc_probe,
> +};
> +module_spi_driver(tsc2046_adc_driver);
> +
> +MODULE_AUTHOR("Oleksij Rempel <kernel@...gutronix.de>");
> +MODULE_DESCRIPTION("TI TSC2046 ADC");
> +MODULE_LICENSE("GPL v2");
> --
> 2.29.2
>
--
With Best Regards,
Andy Shevchenko
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