On 2017-05-14 17:50, Jonathan Cameron wrote:
> On 08/05/17 09:46, Jan Kiszka wrote:
>> This is an upstream port of an IIO driver for the TI ADC108S102 and
>> ADC128S102. The former can be found on the Intel Galileo Gen2 and the
>> Siemens SIMATIC IOT2000. For those boards, ACPI-based enumeration is
>> included.
>>
>> Due to the lack of regulators under ACPI, we hard-code the voltage
>> provided to the VA pin of the ADC to 5 V, the value used on Galileo and
>> IOT2000. For DT usage, the regulator "vref-supply" provides this
>> information. Note that DT usage has not been tested.
>>
>> Original author: Bogdan Pricop <bogdan.pricop@xxxxxxxxxx>
>> Ported from Intel Galileo Gen2 BSP to Intel Yocto kernel:
>> Todor Minchev <todor@xxxxxxxxxxxxx>.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> A small race issue in remove, but otherwise looking very nice.
>
> I'm on the edge of just cleaning that up and applying this,
> but with the reordering I'm suggesting it's probably best you
> give it some thought rather than me just assuming it'll be fine ;)
>
> Jonathan
>> ---
>>
>> Changes in v5:
>> - refactor error handling in adc108s102_read_raw
>> - removed no longer needed checks before regulator_disable
>> (v3 left-over)
>>
>> .../devicetree/bindings/iio/adc/ti-adc108s102.txt | 18 ++
>> drivers/iio/adc/Kconfig | 12 +
>> drivers/iio/adc/Makefile | 1 +
>> drivers/iio/adc/ti-adc108s102.c | 342
>> +++++++++++++++++++++
>> 4 files changed, 373 insertions(+)
>> create mode 100644
>> Documentation/devicetree/bindings/iio/adc/ti-adc108s102.txt
>> create mode 100644 drivers/iio/adc/ti-adc108s102.c
>>
>> diff --git
>> a/Documentation/devicetree/bindings/iio/adc/ti-adc108s102.txt
>> b/Documentation/devicetree/bindings/iio/adc/ti-adc108s102.txt
>> new file mode 100644
>> index 000000000000..bbbbb4a9f58f
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/adc/ti-adc108s102.txt
>> @@ -0,0 +1,18 @@
>> +* Texas Instruments' ADC108S102 and ADC128S102 ADC chip
>> +
>> +Required properties:
>> + - compatible: Should be "ti,adc108s102"
>> + - reg: spi chip select number for the device
>> + - vref-supply: The regulator supply for ADC reference voltage
>> +
>> +Recommended properties:
>> + - spi-max-frequency: Definition as per
>> + Documentation/devicetree/bindings/spi/spi-bus.txt
>> +
>> +Example:
>> +adc@0 {
>> + compatible = "ti,adc108s102";
>> + reg = <0>;
>> + vref-supply = <&vdd_supply>;
>> + spi-max-frequency = <1000000>;
>> +};
>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>> index dedae7adbce9..8b7dae5604f2 100644
>> --- a/drivers/iio/adc/Kconfig
>> +++ b/drivers/iio/adc/Kconfig
>> @@ -572,6 +572,18 @@ config TI_ADC12138
>> This driver can also be built as a module. If so, the module
>> will be
>> called ti-adc12138.
>> +config TI_ADC108S102
>> + tristate "Texas Instruments ADC108S102 and ADC128S102 driver"
>> + depends on SPI
>> + select IIO_BUFFER
>> + select IIO_TRIGGERED_BUFFER
>> + help
>> + Say yes here to build support for Texas Instruments ADC108S102 and
>> + ADC128S102 ADC.
>> +
>> + To compile this driver as a module, choose M here: the module will
>> + be called ti-adc108s102.
>> +
>> config TI_ADC128S052
>> tristate "Texas Instruments ADC128S052/ADC122S021/ADC124S021"
>> depends on SPI
>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
>> index d0012620cd1c..e6c20fe3d4eb 100644
>> --- a/drivers/iio/adc/Makefile
>> +++ b/drivers/iio/adc/Makefile
>> @@ -52,6 +52,7 @@ obj-$(CONFIG_STM32_ADC) += stm32-adc.o
>> obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
>> obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
>> obj-$(CONFIG_TI_ADC12138) += ti-adc12138.o
>> +obj-$(CONFIG_TI_ADC108S102) += ti-adc108s102.o
>> obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
>> obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o
>> obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
>> diff --git a/drivers/iio/adc/ti-adc108s102.c
>> b/drivers/iio/adc/ti-adc108s102.c
>> new file mode 100644
>> index 000000000000..bdf3254619a3
>> --- /dev/null
>> +++ b/drivers/iio/adc/ti-adc108s102.c
>> @@ -0,0 +1,342 @@
>> +/*
>> + * TI ADC108S102 SPI ADC driver
>> + *
>> + * Copyright (c) 2013-2015 Intel Corporation.
>> + * Copyright (c) 2017 Siemens AG
>> + *
>> + * This program is free software; you can redistribute it and/or
>> modify it
>> + * under the terms and conditions of the GNU General Public License,
>> + * version 2, as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope it will be useful, but
>> WITHOUT
>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
>> License for
>> + * more details.
>> + *
>> + * This IIO device driver is designed to work with the following
>> + * analog to digital converters from Texas Instruments:
>> + * ADC108S102
>> + * ADC128S102
>> + * The communication with ADC chip is via the SPI bus (mode 3).
>> + */
>> +
>> +#include <linux/acpi.h>
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/buffer.h>
>> +#include <linux/iio/types.h>
>> +#include <linux/iio/triggered_buffer.h>
>> +#include <linux/iio/trigger_consumer.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/module.h>
>> +#include <linux/property.h>
>> +#include <linux/regulator/consumer.h>
>> +#include <linux/spi/spi.h>
>> +
>> +/*
>> + * In case of ACPI, we use the hard-wired 5000 mV of the Galileo and
>> IOT2000
>> + * boards as default for the reference pin VA. Device tree users
>> encode that
>> + * via the vref-supply regulator.
>> + */
>> +#define ADC108S102_VA_MV_ACPI_DEFAULT 5000
>> +
>> +/*
>> + * Defining the ADC resolution being 12 bits, we can use the same
>> driver for
>> + * both ADC108S102 (10 bits resolution) and ADC128S102 (12 bits
>> resolution)
>> + * chips. The ADC108S102 effectively returns a 12-bit result with the 2
>> + * least-significant bits unset.
>> + */
>> +#define ADC108S102_BITS 12
>> +#define ADC108S102_MAX_CHANNELS 8
>> +
>> +/*
>> + * 16-bit SPI command format:
>> + * [15:14] Ignored
>> + * [13:11] 3-bit channel address
>> + * [10:0] Ignored
>> + */
>> +#define ADC108S102_CMD(ch) ((u16)(ch) << 11)
>> +
>> +/*
>> + * 16-bit SPI response format:
>> + * [15:12] Zeros
>> + * [11:0] 12-bit ADC sample (for ADC108S102, [1:0] will always be 0).
>> + */
>> +#define ADC108S102_RES_DATA(res) ((u16)res & GENMASK(11, 0))
>> +
>> +struct adc108s102_state {
>> + struct spi_device *spi;
>> + struct regulator *reg;
>> + u32 va_millivolt;
>> + /* SPI transfer used by triggered buffer handler*/
>> + struct spi_transfer ring_xfer;
>> + /* SPI transfer used by direct scan */
>> + struct spi_transfer scan_single_xfer;
>> + /* SPI message used by ring_xfer SPI transfer */
>> + struct spi_message ring_msg;
>> + /* SPI message used by scan_single_xfer SPI transfer */
>> + struct spi_message scan_single_msg;
>> +
>> + /*
>> + * SPI message buffers:
>> + * tx_buf: |C0|C1|C2|C3|C4|C5|C6|C7|XX|
>> + * rx_buf: |XX|R0|R1|R2|R3|R4|R5|R6|R7|tt|tt|tt|tt|
>> + *
>> + * tx_buf: 8 channel read commands, plus 1 dummy command
>> + * rx_buf: 1 dummy response, 8 channel responses, plus 64-bit
>> timestamp
>> + */
>> + __be16 rx_buf[13] ____cacheline_aligned;
>> + __be16 tx_buf[9] ____cacheline_aligned;
>> +};
>> +
>> +#define ADC108S102_V_CHAN(index) \
>> + { \
>> + .type = IIO_VOLTAGE, \
>> + .indexed = 1, \
>> + .channel = index, \
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
>> + BIT(IIO_CHAN_INFO_SCALE), \
>> + .address = index, \
>> + .scan_index = index, \
>> + .scan_type = { \
>> + .sign = 'u', \
>> + .realbits = ADC108S102_BITS, \
>> + .storagebits = 16, \
>> + .endianness = IIO_BE, \
>> + }, \
>> + }
>> +
>> +static const struct iio_chan_spec adc108s102_channels[] = {
>> + ADC108S102_V_CHAN(0),
>> + ADC108S102_V_CHAN(1),
>> + ADC108S102_V_CHAN(2),
>> + ADC108S102_V_CHAN(3),
>> + ADC108S102_V_CHAN(4),
>> + ADC108S102_V_CHAN(5),
>> + ADC108S102_V_CHAN(6),
>> + ADC108S102_V_CHAN(7),
>> + IIO_CHAN_SOFT_TIMESTAMP(8),
>> +};
>> +
>> +static int adc108s102_update_scan_mode(struct iio_dev *indio_dev,
>> + unsigned long const *active_scan_mask)
>> +{
>> + struct adc108s102_state *st = iio_priv(indio_dev);
>> + unsigned int bit, cmds;
>> +
>> + /*
>> + * Fill in the first x shorts of tx_buf with the number of channels
>> + * enabled for sampling by the triggered buffer.
>> + */
>> + cmds = 0;
>> + for_each_set_bit(bit, active_scan_mask, ADC108S102_MAX_CHANNELS)
>> + st->tx_buf[cmds++] = cpu_to_be16(ADC108S102_CMD(bit));
>> +
>> + /* One dummy command added, to clock in the last response */
>> + st->tx_buf[cmds++] = 0x00;
>> +
>> + /* build SPI ring message */
>> + st->ring_xfer.tx_buf = &st->tx_buf[0];
>> + st->ring_xfer.rx_buf = &st->rx_buf[0];
>> + st->ring_xfer.len = cmds * sizeof(st->tx_buf[0]);
>> +
>> + spi_message_init_with_transfers(&st->ring_msg, &st->ring_xfer, 1);
>> +
>> + return 0;
>> +}
>> +
>> +static irqreturn_t adc108s102_trigger_handler(int irq, void *p)
>> +{
>> + struct iio_poll_func *pf = p;
>> + struct iio_dev *indio_dev = pf->indio_dev;
>> + struct adc108s102_state *st = iio_priv(indio_dev);
>> + int ret;
>> +
>> + ret = spi_sync(st->spi, &st->ring_msg);
>> + if (ret < 0)
>> + goto out_notify;
>> +
>> + /* Skip the dummy response in the first slot */
>> + iio_push_to_buffers_with_timestamp(indio_dev,
>> + (u8 *)&st->rx_buf[1],
>> + iio_get_time_ns(indio_dev));
>> +
>> +out_notify:
>> + iio_trigger_notify_done(indio_dev->trig);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static int adc108s102_scan_direct(struct adc108s102_state *st,
>> unsigned int ch)
>> +{
>> + int ret;
>> +
>> + st->tx_buf[0] = cpu_to_be16(ADC108S102_CMD(ch));
>> + ret = spi_sync(st->spi, &st->scan_single_msg);
>> + if (ret)
>> + return ret;
>> +
>> + /* Skip the dummy response in the first slot */
>> + return be16_to_cpu(st->rx_buf[1]);
>> +}
>> +
>> +static int adc108s102_read_raw(struct iio_dev *indio_dev,
>> + struct iio_chan_spec const *chan,
>> + int *val, int *val2, long m)
>> +{
>> + struct adc108s102_state *st = iio_priv(indio_dev);
>> + int ret;
>> +
>> + switch (m) {
>> + case IIO_CHAN_INFO_RAW:
>> + ret = iio_device_claim_direct_mode(indio_dev);
>> + if (ret)
>> + return ret;
>> +
>> + ret = adc108s102_scan_direct(st, chan->address);
>> +
>> + iio_device_release_direct_mode(indio_dev);
>> +
>> + if (ret < 0)
>> + return ret;
>> +
>> + *val = ADC108S102_RES_DATA(ret);
>> +
>> + return IIO_VAL_INT;
>> + case IIO_CHAN_INFO_SCALE:
>> + if (chan->type != IIO_VOLTAGE)
>> + break;
>> +
>> + *val = st->va_millivolt;
>> + *val2 = chan->scan_type.realbits;
>> +
>> + return IIO_VAL_FRACTIONAL_LOG2;
>> + default:
>> + break;
>> + }
>> +
>> + return -EINVAL;
>> +}
>> +
>> +static const struct iio_info adc108s102_info = {
>> + .read_raw = &adc108s102_read_raw,
>> + .update_scan_mode = &adc108s102_update_scan_mode,
>> + .driver_module = THIS_MODULE,
>> +};
>> +
>> +static int adc108s102_probe(struct spi_device *spi)
>> +{
>> + struct adc108s102_state *st;
>> + struct iio_dev *indio_dev;
>> + int ret;
>> +
>> + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
>> + if (!indio_dev)
>> + return -ENOMEM;
>> +
>> + st = iio_priv(indio_dev);
>> +
>> + if (ACPI_COMPANION(&spi->dev)) {
>> + st->va_millivolt = ADC108S102_VA_MV_ACPI_DEFAULT;
>> + } else {
>> + st->reg = devm_regulator_get(&spi->dev, "vref");
>> + if (IS_ERR(st->reg))
>> + return PTR_ERR(st->reg);
>> +
>> + ret = regulator_enable(st->reg);
>> + if (ret < 0) {
>> + dev_err(&spi->dev, "Cannot enable vref regulator\n");
>> + return ret;
>> + }
>> +
>> + ret = regulator_get_voltage(st->reg);
>> + if (ret < 0) {
>> + dev_err(&spi->dev, "vref get voltage failed\n");
>> + return ret;
>> + }
>> +
>> + st->va_millivolt = ret / 1000;
>> + }
>> +
>> + spi_set_drvdata(spi, indio_dev);
>> + st->spi = spi;
>> +
>> + indio_dev->name = spi->modalias;
>> + indio_dev->dev.parent = &spi->dev;
>> + indio_dev->modes = INDIO_DIRECT_MODE;
>> + indio_dev->channels = adc108s102_channels;
>> + indio_dev->num_channels = ARRAY_SIZE(adc108s102_channels);
>> + indio_dev->info = &adc108s102_info;
>> +
>> + /* Setup default message */
>> + st->scan_single_xfer.tx_buf = st->tx_buf;
>> + st->scan_single_xfer.rx_buf = st->rx_buf;
>> + st->scan_single_xfer.len = 2 * sizeof(st->tx_buf[0]);
>> +
>> + spi_message_init_with_transfers(&st->scan_single_msg,
>> + &st->scan_single_xfer, 1);
>> +
>> + ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
>> + &adc108s102_trigger_handler, NULL);
>> + if (ret)
>> + goto error_disable_reg;
>> +
>> + ret = devm_iio_device_register(&spi->dev, indio_dev);
>> + if (ret) {
>> + dev_err(&spi->dev, "Failed to register IIO device\n");
>> + goto error_disable_reg;
>> + }
>> + return 0;
>> +
>> +error_disable_reg:
>> + regulator_disable(st->reg);
>> +
>> + return ret;
>> +}
>> +
>> +static int adc108s102_remove(struct spi_device *spi)
>> +{
>> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
>> + struct adc108s102_state *st = iio_priv(indio_dev);
>> +
>> + regulator_disable(st->reg);
> This turns off the regulator before we remove the user space interfaces
> unfortunately. Please use iio_device_register then explicitly call
> the unregister before this to ensure the unwind order is the
> reverse of that in probe. Technically you should do the same
> for iio_triggered_buffer setup but neater to just reorder
> probe to do the regulator enable after that then we are in the
> obviously correct category which reviewers always like.
I'll look into this later this week and send out a tested update.
Thanks!
Jan
--
Siemens AG, Corporate Technology, CT RDA ITP SES-DE
Corporate Competence Center Embedded Linux
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
