2016-07-19 7:02 GMT+09:00 Peter Meerwald-Stadler <pmeerw@xxxxxxxxxx>:
>
>> This adds Texas Instruments' ADC12130/ADC12132/ADC12138 12-bit plus
>> sign ADC driver. I have tested with the ADC12138. The ADC12130 and
>> ADC12132 are not tested but these are similar to ADC12138 except that
>> the mode programming instruction is a bit different.
>
> minor comments below
>
>> Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
>> Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
>> Cc: Hartmut Knaack <knaack.h@xxxxxx>
>> Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
>> Cc: Peter Meerwald <pmeerw@xxxxxxxxxx>
>> ---
>> .../devicetree/bindings/iio/adc/ti-adc12138.txt | 32 ++
>> drivers/iio/adc/Kconfig | 12 +
>> drivers/iio/adc/Makefile | 1 +
>> drivers/iio/adc/ti-adc12138.c | 541 +++++++++++++++++++++
>> 4 files changed, 586 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/iio/adc/ti-adc12138.txt
>> create mode 100644 drivers/iio/adc/ti-adc12138.c
>>
>> diff --git a/Documentation/devicetree/bindings/iio/adc/ti-adc12138.txt b/Documentation/devicetree/bindings/iio/adc/ti-adc12138.txt
>> new file mode 100644
>> index 0000000..3a11d2a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/adc/ti-adc12138.txt
>> @@ -0,0 +1,32 @@
>> +* Texas Instruments' ADC12130/ADC12132/ADC12138
>> +
>> +Required properties:
>> + - compatible: Should be one of
>> + * "ti,adc12130"
>> + * "ti,adc12132"
>> + * "ti,adc12138"
>> + - reg: SPI chip select number for the device
>> + - interrupts: Should contain interrupt for EOC (end of conversion)
>> + - clocks: phandle to conversion clock input
>> + - spi-max-frequency: Definision as per
>> + Documentation/devicetree/bindings/spi/spi-bus.txt
>> + - vref-p-supply: The regulator supply for positive analog voltage reference
>> +
>> +Optional properties:
>> + - vref-n-supply: The regulator supply for negative analog voltage reference
>> + If not specified, this is assumed to be analog ground.
>> + - acquisition-time: The number of conversion clock periods for the S/H's
>> + acquisition time. Should be one of 6, 10, 18, 34. If not specified,
>> + default value of 10 is used.
>> +
>> +Example:
>> +adc@0 {
>> + compatible = "ti,adc12138";
>> + reg = <0>;
>> + interrupts = <28 IRQ_TYPE_EDGE_RISING>;
>> + interrupt-parent = <&gpio1>;
>> + clocks = <&cclk>;
>> + vref-p-supply = <&ldo4_reg>;
>> + spi-max-frequency = <5000000>;
>> + acquisition-time = <6>;
>> +};
>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>> index fa0ff29..0783291 100644
>> --- a/drivers/iio/adc/Kconfig
>> +++ b/drivers/iio/adc/Kconfig
>> @@ -414,6 +414,18 @@ config TI_ADC0832
>> This driver can also be built as a module. If so, the module will be
>> called ti-adc0832.
>>
>> +config TI_ADC12138
>> + tristate "Texas Instruments ADC12130/ADC12132/ADC12138"
>> + depends on SPI
>> + select IIO_BUFFER
>> + select IIO_TRIGGERED_BUFFER
>> + help
>> + If you say yes here you get support for Texas Instruments ADC12130,
>> + ADC12132and ADC12138 chips.
>
> space before 'and' missing
Ugh.
>> +
>> + This driver can also be built as a module. If so, the module will be
>> + called ti-adc12138.
>> +
>> 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 599714b..3ae4ae3 100644
>> --- a/drivers/iio/adc/Makefile
>> +++ b/drivers/iio/adc/Makefile
>> @@ -40,6 +40,7 @@ obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
>> obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.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_ADC128S052) += ti-adc128s052.o
>> obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
>> obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
>> diff --git a/drivers/iio/adc/ti-adc12138.c b/drivers/iio/adc/ti-adc12138.c
>> new file mode 100644
>> index 0000000..e7bd986
>> --- /dev/null
>> +++ b/drivers/iio/adc/ti-adc12138.c
>> @@ -0,0 +1,541 @@
>> +/*
>> + * ADC12130/ADC12132/ADC12138 12-bit plus sign ADC driver
>> + *
>> + * Copyright (c) 2016 Akinobu Mita <akinobu.mita@xxxxxxxxx>
>> + *
>> + * This file is subject to the terms and conditions of version 2 of
>> + * the GNU General Public License. See the file COPYING in the main
>> + * directory of this archive for more details.
>> + *
>> + * Datasheet: http://www.ti.com/lit/ds/symlink/adc12138.pdf
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/completion.h>
>> +#include <linux/clk.h>
>> +#include <linux/spi/spi.h>
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/buffer.h>
>> +#include <linux/iio/trigger.h>
>> +#include <linux/iio/triggered_buffer.h>
>> +#include <linux/iio/trigger_consumer.h>
>> +#include <linux/regulator/consumer.h>
>> +
>> +#define ADC12138_MODE_AUTO_CAL 0x08
>> +#define ADC12138_MODE_READ_STATUS 0x0c
>> +#define ADC12138_MODE_ACQUISITION_TIME_6 0x0e
>> +#define ADC12138_MODE_ACQUISITION_TIME_10 0x4e
>> +#define ADC12138_MODE_ACQUISITION_TIME_18 0x8e
>> +#define ADC12138_MODE_ACQUISITION_TIME_34 0xce
>> +
>> +#define ADC12138_STATUS_CAL BIT(6)
>> +
>> +enum {
>> + adc12130,
>> + adc12132,
>> + adc12138,
>> +};
>> +
>> +struct adc12138 {
>> + struct spi_device *spi;
>> + unsigned int id;
>> + /* conversion clock */
>> + struct clk *cclk;
>> + /* positive analog voltage reference */
>> + struct regulator *vref_p;
>> + /* negative analog voltage reference */
>> + struct regulator *vref_n;
>> + struct mutex lock;
>> + struct completion complete;
>> + unsigned int acquisition_time;
>
> unit? ms? µs?
This is specified by the number of conversion clock (cclk) periods.
I'll add a comment about it.
>> +
>> + u8 tx_buf[2] ____cacheline_aligned;
>> + u8 rx_buf[2];
>> +};
>> +
>> +#define ADC12138_VOLTAGE_CHANNEL(chan) \
>> + { \
>> + .type = IIO_VOLTAGE, \
>> + .indexed = 1, \
>> + .channel = chan, \
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
>> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
>> + | BIT(IIO_CHAN_INFO_OFFSET), \
>> + .scan_index = chan, \
>> + .scan_type = { \
>> + .sign = 's', \
>> + .realbits = 13, \
>> + .storagebits = 16, \
>> + .shift = 3, \
>> + .endianness = IIO_BE, \
>> + }, \
>> + }
>> +
>> +#define ADC12138_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si_offset) \
>> + { \
>> + .type = IIO_VOLTAGE, \
>> + .indexed = 1, \
>> + .channel = (chan1), \
>> + .channel2 = (chan2), \
>> + .differential = 1, \
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
>> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
>> + | BIT(IIO_CHAN_INFO_OFFSET), \
>> + .scan_index = (chan1) + (si_offset), \
>> + .scan_type = { \
>> + .sign = 's', \
>> + .realbits = 13, \
>> + .storagebits = 16, \
>> + .shift = 3, \
>> + .endianness = IIO_BE, \
>> + }, \
>> + }
>> +
>> +static const struct iio_chan_spec adc12132_channels[] = {
>> + ADC12138_VOLTAGE_CHANNEL(0),
>> + ADC12138_VOLTAGE_CHANNEL(1),
>> + ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
>> + ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 2),
>> + IIO_CHAN_SOFT_TIMESTAMP(4),
>> +};
>> +
>> +static const struct iio_chan_spec adc12138_channels[] = {
>> + ADC12138_VOLTAGE_CHANNEL(0),
>> + ADC12138_VOLTAGE_CHANNEL(1),
>> + ADC12138_VOLTAGE_CHANNEL(2),
>> + ADC12138_VOLTAGE_CHANNEL(3),
>> + ADC12138_VOLTAGE_CHANNEL(4),
>> + ADC12138_VOLTAGE_CHANNEL(5),
>> + ADC12138_VOLTAGE_CHANNEL(6),
>> + ADC12138_VOLTAGE_CHANNEL(7),
>> + ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
>> + ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 8),
>> + ADC12138_VOLTAGE_CHANNEL_DIFF(2, 3, 8),
>> + ADC12138_VOLTAGE_CHANNEL_DIFF(3, 2, 8),
>> + ADC12138_VOLTAGE_CHANNEL_DIFF(4, 5, 8),
>> + ADC12138_VOLTAGE_CHANNEL_DIFF(5, 4, 8),
>> + ADC12138_VOLTAGE_CHANNEL_DIFF(6, 7, 8),
>> + ADC12138_VOLTAGE_CHANNEL_DIFF(7, 6, 8),
>> + IIO_CHAN_SOFT_TIMESTAMP(16),
>> +};
>> +
>> +static int adc12138_mode_programming(struct adc12138 *adc, u8 mode,
>> + void *rx_buf, int len)
>> +{
>> + struct spi_transfer xfer = {
>> + .tx_buf = adc->tx_buf,
>> + .rx_buf = adc->rx_buf,
>> + .len = len,
>> + };
>> + int ret;
>> +
>> + /* Skip disused bits for ADC12130 and ADC12132 */
>
> probably 'unused' instead of 'disused'
OK.
>> + if (adc->id != adc12138)
>> + mode = (mode & 0xc0) | ((mode & 0x0f) << 2);
>> +
>> + adc->tx_buf[0] = mode;
>> +
>> + ret = spi_sync_transfer(adc->spi, &xfer, 1);
>> + if (ret)
>> + return ret;
>> +
>> + memcpy(rx_buf, adc->rx_buf, len);
>> +
>> + return 0;
>> +}
>> +
>> +static int adc12138_read_status(struct adc12138 *adc)
>> +{
>> + u8 rx_buf[2];
>> + int ret;
>> +
>> + ret = adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
>> + rx_buf, 2);
>> + if (ret)
>> + return ret;
>> +
>> + return (rx_buf[0] << 1) | (rx_buf[1] >> 7);
>> +}
>> +
>> +static int __adc12138_start_conv(struct adc12138 *adc,
>> + struct iio_chan_spec const *channel,
>> + void *data, int len)
>> +
>> +{
>> + const u8 ch_to_mux[] = { 0, 4, 1, 5, 2, 6, 3, 7 };
>> + u8 mode = (ch_to_mux[channel->channel] << 4) |
>> + (channel->differential ? 0 : 0x80);
>> +
>> + return adc12138_mode_programming(adc, mode, data, len);
>> +}
>> +
>> +static int adc12138_start_conv(struct adc12138 *adc,
>> + struct iio_chan_spec const *channel)
>> +{
>> + u8 trash;
>> +
>> + return __adc12138_start_conv(adc, channel, &trash, 1);
>> +}
>> +
>> +static int adc12138_start_and_read_conv(struct adc12138 *adc,
>> + struct iio_chan_spec const *channel,
>> + __be16 *data)
>> +{
>> + return __adc12138_start_conv(adc, channel, data, 2);
>> +}
>> +
>> +static int adc12138_read_conv_data(struct adc12138 *adc, __be16 *value)
>> +{
>> + /* Issue a read status instruction and read previous conversion data */
>> + return adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
>> + value, sizeof(*value));
>> +}
>> +
>> +static int adc12138_wait_eoc(struct adc12138 *adc, unsigned long timeout)
>> +{
>> + if (!wait_for_completion_timeout(&adc->complete, timeout))
>> + return -ETIMEDOUT;
>> +
>> + return 0;
>> +}
>> +
>> +static int adc12138_adc_conversion(struct adc12138 *adc,
>> + struct iio_chan_spec const *channel,
>> + __be16 *value)
>> +{
>> + int ret;
>> +
>> + reinit_completion(&adc->complete);
>> +
>> + ret = adc12138_start_conv(adc, channel);
>> + if (ret)
>> + return ret;
>> +
>> + ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
>> + if (ret)
>> + return ret;
>> +
>> + return adc12138_read_conv_data(adc, value);
>> +}
>> +
>> +static int adc12138_read_raw(struct iio_dev *iio,
>> + struct iio_chan_spec const *channel, int *value,
>> + int *shift, long mask)
>> +{
>> + struct adc12138 *adc = iio_priv(iio);
>> + int ret;
>> + __be16 data;
>> +
>> + switch (mask) {
>> + case IIO_CHAN_INFO_RAW:
>
> what if buffered reads have been set up? probably use
> iio_device_claim_direct_mode()
Maybe it is safe because the ADC data is always requested and retrieved
while holding adc12138.lock from adc12138_read_raw() and
adc12138_trigger_handler(). Is it better to restrict direct mode and
return -EBUSY while buffer mode is enabled?
(BTW, I realized that I can use iio_dev->mlock instead of adc12138.lock)
>> + mutex_lock(&adc->lock);
>> + ret = adc12138_adc_conversion(adc, channel, &data);
>> + mutex_unlock(&adc->lock);
>> + if (ret)
>> + return ret;
>> +
>> + *value = sign_extend32(be16_to_cpu(data) >> 3, 12);
>> +
>> + return IIO_VAL_INT;
>> + case IIO_CHAN_INFO_SCALE:
>> + ret = regulator_get_voltage(adc->vref_p);
>> + if (ret < 0)
>> + return ret;
>> + *value = ret;
>> +
>> + if (!IS_ERR(adc->vref_n)) {
>> + ret = regulator_get_voltage(adc->vref_n);
>> + if (ret < 0)
>> + return ret;
>> + *value -= ret;
>> + }
>> +
>> + /* convert regulator output voltage to mV */
>> + *value /= 1000;
>> + *shift = channel->scan_type.realbits - 1;
>> +
>> + return IIO_VAL_FRACTIONAL_LOG2;
>> + case IIO_CHAN_INFO_OFFSET:
>> + if (!IS_ERR(adc->vref_n)) {
>> + *value = regulator_get_voltage(adc->vref_n);
>> + if (*value < 0)
>> + return *value;
>> + } else {
>> + *value = 0;
>> + }
>> +
>> + /* convert regulator output voltage to mV */
>> + *value /= 1000;
>> +
>> + return IIO_VAL_INT;
>> + }
>> +
>> + return -EINVAL;
>> +}
>> +
>> +static const struct iio_info adc12138_info = {
>> + .read_raw = adc12138_read_raw,
>> + .driver_module = THIS_MODULE,
>> +};
>> +
>> +static int adc12138_init(struct adc12138 *adc)
>> +{
>> + int ret;
>> + int status;
>> + u8 mode;
>> + u8 trash;
>> +
>> + reinit_completion(&adc->complete);
>> +
>> + ret = adc12138_mode_programming(adc, ADC12138_MODE_AUTO_CAL, &trash, 1);
>> + if (ret)
>> + return ret;
>> +
>> + /* data output at this time has no significance */
>> + status = adc12138_read_status(adc);
>> + if (status < 0)
>> + return status;
>> +
>> + adc12138_wait_eoc(adc, msecs_to_jiffies(100));
>> +
>> + status = adc12138_read_status(adc);
>> + if (status & ADC12138_STATUS_CAL) {
>> + dev_warn(&adc->spi->dev,
>> + "Auto Cal sequence is still in progress: %#x\n",
>> + status);
>> + return -EIO;
>> + }
>> +
>> + switch (adc->acquisition_time) {
>> + case 6:
>> + mode = ADC12138_MODE_ACQUISITION_TIME_6;
>> + break;
>> + case 10:
>> + mode = ADC12138_MODE_ACQUISITION_TIME_10;
>> + break;
>> + case 18:
>> + mode = ADC12138_MODE_ACQUISITION_TIME_18;
>> + break;
>> + case 34:
>> + mode = ADC12138_MODE_ACQUISITION_TIME_34;
>> + break;
>> + default:
>> + return -EINVAL;
>> + }
>> +
>> + return adc12138_mode_programming(adc, mode, &trash, 1);
>> +}
>> +
>> +static irqreturn_t adc12138_trigger_handler(int irq, void *p)
>> +{
>> + struct iio_poll_func *pf = p;
>> + struct iio_dev *indio_dev = pf->indio_dev;
>> + struct adc12138 *adc = iio_priv(indio_dev);
>> + __be16 data[20] = { };
>
> why { } here?
To initialize with zero and avoids exposing kernel stack to userspace
through padding entries. I could use memset here.
> why 20?
When all scan elements are enabled, the sample data requires 40 bytes
(2 bytes ADC data * 16 channels + 8 bytes timestamp).
I'll add comments about these.
>> + __be16 trash;
>> + int ret;
>> + int scan_index;
>> + int i = 0;
>> +
>> + mutex_lock(&adc->lock);
>> +
>> + for_each_set_bit(scan_index, indio_dev->active_scan_mask,
>> + indio_dev->masklength) {
>> + const struct iio_chan_spec *scan_chan =
>> + &indio_dev->channels[scan_index];
>> +
>> + reinit_completion(&adc->complete);
>> +
>> + ret = adc12138_start_and_read_conv(adc, scan_chan,
>> + i ? &data[i - 1] : &trash);
>> + if (ret) {
>> + dev_warn(&adc->spi->dev,
>> + "failed to start conversion\n");
>> + goto out;
>> + }
>> +
>> + ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
>> + if (ret) {
>> + dev_warn(&adc->spi->dev, "wait eoc timeout\n");
>> + goto out;
>> + }
>> +
>> + i++;
>> + }
>> +
>> + if (i) {
>> + ret = adc12138_read_conv_data(adc, &data[i - 1]);
>> + if (ret) {
>> + dev_warn(&adc->spi->dev,
>> + "failed to get conversion data\n");
>> + goto out;
>> + }
>> + }
>> +
>> + iio_push_to_buffers_with_timestamp(indio_dev, data, iio_get_time_ns());
>> +out:
>> + mutex_unlock(&adc->lock);
>> +
>> + iio_trigger_notify_done(indio_dev->trig);
>> +
>> + return IRQ_HANDLED;
>> +}
--
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