Re: [PATCH v3] IIO ADC support for AD7923

[Jonathan Cameron <jic23@kernel.org>]

On 02/13/2013 09:20 AM, Jonathan Cameron wrote:
> On 13/02/13 09:19, Lars-Peter Clausen wrote:
>> On 02/13/2013 07:47 AM, Christophe Leroy wrote:
>>> This patch adds support for Analog Devices AD7923 ADC in the IIO Subsystem.
>>>
>>> Signed-off-by: Patrick Vasseur <patrick.vasseur@c-s.fr>
>>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
>>
>> Looks good, thanks.
>>
>> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
> Just missed the merge window I'm afraid. I'll queue this up for
> going into staging-next after Linus closes the main merge window.

Applied to the togreg branch of iio.git
>>
>>>
>>> diff -urN linux-next-e347c98/drivers/iio/adc/Kconfig linux-next-e347c98.new/drivers/iio/adc/Kconfig
>>> --- linux-next-e347c98/drivers/iio/adc/Kconfig    2013-02-08 05:22:35.000000000 +0100
>>> +++ linux-next-e347c98.new/drivers/iio/adc/Kconfig    2013-02-12 13:02:52.000000000 +0100
>>> @@ -30,6 +30,18 @@
>>>         To compile this driver as a module, choose M here: the
>>>         module will be called ad7298.
>>>
>>> +config AD7923
>>> +    tristate "Analog Devices AD7923 ADC driver"
>>> +    depends on SPI
>>> +    select IIO_BUFFER
>>> +    select IIO_TRIGGERED_BUFFER
>>> +    help
>>> +      Say yes here to build support for Analog Devices AD7923
>>> +      4 Channel ADC with temperature sensor.
>>> +
>>> +      To compile this driver as a module, choose M here: the
>>> +      module will be called ad7923.
>>> +
>>>   config AD7791
>>>       tristate "Analog Devices AD7791 ADC driver"
>>>       depends on SPI
>>> diff -urN linux-next-e347c98/drivers/iio/adc/Makefile linux-next-e347c98.new/drivers/iio/adc/Makefile
>>> --- linux-next-e347c98/drivers/iio/adc/Makefile    2013-02-08 05:22:35.000000000 +0100
>>> +++ linux-next-e347c98.new/drivers/iio/adc/Makefile    2013-02-12 13:03:02.000000000 +0100
>>> @@ -5,6 +5,7 @@
>>>   obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
>>>   obj-$(CONFIG_AD7266) += ad7266.o
>>>   obj-$(CONFIG_AD7298) += ad7298.o
>>> +obj-$(CONFIG_AD7923) += ad7923.o
>>>   obj-$(CONFIG_AD7476) += ad7476.o
>>>   obj-$(CONFIG_AD7791) += ad7791.o
>>>   obj-$(CONFIG_AD7793) += ad7793.o
>>> diff -urN linux-next-e347c98/drivers/iio/adc/ad7923.c linux-next-e347c98.new/drivers/iio/adc/ad7923.c
>>> --- linux-next-e347c98/drivers/iio/adc/ad7923.c    1970-01-01 01:00:00.000000000 +0100
>>> +++ linux-next-e347c98.new/drivers/iio/adc/ad7923.c    2013-02-13 02:03:38.000000000 +0100
>>> @@ -0,0 +1,298 @@
>>> +/*
>>> + * AD7923 SPI ADC driver
>>> + *
>>> + * Copyright 2011 Analog Devices Inc (from AD7923 Driver)
>>> + * Copyright 2012 CS Systemes d'Information
>>> + *
>>> + * Licensed under the GPL-2.
>>> + */
>>> +
>>> +#include <linux/device.h>
>>> +#include <linux/kernel.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/sysfs.h>
>>> +#include <linux/spi/spi.h>
>>> +#include <linux/err.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/module.h>
>>> +#include <linux/interrupt.h>
>>> +
>>> +#include <linux/iio/iio.h>
>>> +#include <linux/iio/sysfs.h>
>>> +#include <linux/iio/buffer.h>
>>> +#include <linux/iio/trigger_consumer.h>
>>> +#include <linux/iio/triggered_buffer.h>
>>> +
>>> +#define AD7923_WRITE_CR        (1 << 11)    /* write control register */
>>> +#define AD7923_RANGE        (1 << 1)    /* range to REFin */
>>> +#define AD7923_CODING        (1 << 0)    /* coding is straight binary */
>>> +#define AD7923_PM_MODE_AS    (1)        /* auto shutdown */
>>> +#define AD7923_PM_MODE_FS    (2)        /* full shutdown */
>>> +#define AD7923_PM_MODE_OPS    (3)        /* normal operation */
>>> +#define AD7923_CHANNEL_0    (0)        /* analog input 0 */
>>> +#define AD7923_CHANNEL_1    (1)        /* analog input 1 */
>>> +#define AD7923_CHANNEL_2    (2)        /* analog input 2 */
>>> +#define AD7923_CHANNEL_3    (3)        /* analog input 3 */
>>> +#define AD7923_SEQUENCE_OFF    (0)        /* no sequence fonction */
>>> +#define AD7923_SEQUENCE_PROTECT    (2)        /* no interrupt write cycle */
>>> +#define AD7923_SEQUENCE_ON    (3)        /* continuous sequence */
>>> +
>>> +#define AD7923_MAX_CHAN        4
>>> +
>>> +#define AD7923_PM_MODE_WRITE(mode)    (mode << 4)    /* write mode */
>>> +#define AD7923_CHANNEL_WRITE(channel)    (channel << 6)    /* write channel */
>>> +#define AD7923_SEQUENCE_WRITE(sequence)    (((sequence & 1) << 3) \
>>> +                    + ((sequence & 2) << 9))
>>> +                        /* write sequence fonction */
>>> +/* left shift for CR : bit 11 transmit in first */
>>> +#define AD7923_SHIFT_REGISTER    4
>>> +
>>> +/* val = value, dec = left shift, bits = number of bits of the mask */
>>> +#define EXTRACT(val, dec, bits)        ((val >> dec) & ((1 << bits) - 1))
>>> +
>>> +struct ad7923_state {
>>> +    struct spi_device        *spi;
>>> +    struct spi_transfer        ring_xfer[5];
>>> +    struct spi_transfer        scan_single_xfer[2];
>>> +    struct spi_message        ring_msg;
>>> +    struct spi_message        scan_single_msg;
>>> +    /*
>>> +     * DMA (thus cache coherency maintenance) requires the
>>> +     * transfer buffers to live in their own cache lines.
>>> +     */
>>> +    __be16                rx_buf[4] ____cacheline_aligned;
>>> +    __be16                tx_buf[4];
>>> +};
>>> +
>>> +#define AD7923_V_CHAN(index)                        \
>>> +    {                                \
>>> +        .type = IIO_VOLTAGE,                    \
>>> +        .indexed = 1,                        \
>>> +        .channel = index,                    \
>>> +        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |        \
>>> +        IIO_CHAN_INFO_SCALE_SHARED_BIT,                \
>>> +        .address = index,                    \
>>> +        .scan_index = index,                    \
>>> +        .scan_type = {                        \
>>> +            .sign = 'u',                    \
>>> +            .realbits = 12,                    \
>>> +            .storagebits = 16,                \
>>> +            .endianness = IIO_BE,                \
>>> +        },                            \
>>> +    }
>>> +
>>> +static const struct iio_chan_spec ad7923_channels[] = {
>>> +    AD7923_V_CHAN(0),
>>> +    AD7923_V_CHAN(1),
>>> +    AD7923_V_CHAN(2),
>>> +    AD7923_V_CHAN(3),
>>> +    IIO_CHAN_SOFT_TIMESTAMP(4),
>>> +};
>>> +
>>> +/**
>>> + * ad7923_update_scan_mode() setup the spi transfer buffer for the new scan mask
>>> + **/
>>> +static int ad7923_update_scan_mode(struct iio_dev *indio_dev,
>>> +    const unsigned long *active_scan_mask)
>>> +{
>>> +    struct ad7923_state *st = iio_priv(indio_dev);
>>> +    int i, cmd, len;
>>> +
>>> +    len = 0;
>>> +    for_each_set_bit(i, active_scan_mask, AD7923_MAX_CHAN) {
>>> +        cmd = AD7923_WRITE_CR | AD7923_CODING | AD7923_RANGE |
>>> +            AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS) |
>>> +            AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) |
>>> +            AD7923_CHANNEL_WRITE(i);
>>> +        cmd <<= AD7923_SHIFT_REGISTER;
>>> +        st->tx_buf[len++] = cpu_to_be16(cmd);
>>> +    }
>>> +    /* build spi ring message */
>>> +    st->ring_xfer[0].tx_buf = &st->tx_buf[0];
>>> +    st->ring_xfer[0].len = len;
>>> +    st->ring_xfer[0].cs_change = 1;
>>> +
>>> +    spi_message_init(&st->ring_msg);
>>> +    spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
>>> +
>>> +    for (i = 0; i < len; i++) {
>>> +        st->ring_xfer[i + 1].rx_buf = &st->rx_buf[i];
>>> +        st->ring_xfer[i + 1].len = 2;
>>> +        st->ring_xfer[i + 1].cs_change = 1;
>>> +        spi_message_add_tail(&st->ring_xfer[i + 1], &st->ring_msg);
>>> +    }
>>> +    /* make sure last transfer cs_change is not set */
>>> +    st->ring_xfer[i + 1].cs_change = 0;
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +/**
>>> + * ad7923_trigger_handler() bh of trigger launched polling to ring buffer
>>> + *
>>> + * Currently there is no option in this driver to disable the saving of
>>> + * timestamps within the ring.
>>> + **/
>>> +static irqreturn_t ad7923_trigger_handler(int irq, void *p)
>>> +{
>>> +    struct iio_poll_func *pf = p;
>>> +    struct iio_dev *indio_dev = pf->indio_dev;
>>> +    struct ad7923_state *st = iio_priv(indio_dev);
>>> +    s64 time_ns = 0;
>>> +    int b_sent;
>>> +
>>> +    b_sent = spi_sync(st->spi, &st->ring_msg);
>>> +    if (b_sent)
>>> +        goto done;
>>> +
>>> +    if (indio_dev->scan_timestamp) {
>>> +        time_ns = iio_get_time_ns();
>>> +        memcpy((u8 *)st->rx_buf + indio_dev->scan_bytes - sizeof(s64),
>>> +            &time_ns, sizeof(time_ns));
>>> +    }
>>> +
>>> +    iio_push_to_buffers(indio_dev, (u8 *)st->rx_buf);
>>> +
>>> +done:
>>> +    iio_trigger_notify_done(indio_dev->trig);
>>> +
>>> +    return IRQ_HANDLED;
>>> +}
>>> +
>>> +static int ad7923_scan_direct(struct ad7923_state *st, unsigned ch)
>>> +{
>>> +    int ret, cmd;
>>> +
>>> +    cmd = AD7923_WRITE_CR | AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS) |
>>> +        AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) | AD7923_CODING |
>>> +        AD7923_CHANNEL_WRITE(ch) | AD7923_RANGE;
>>> +    cmd <<= AD7923_SHIFT_REGISTER;
>>> +    st->tx_buf[0] = cpu_to_be16(cmd);
>>> +
>>> +    ret = spi_sync(st->spi, &st->scan_single_msg);
>>> +    if (ret)
>>> +        return ret;
>>> +
>>> +    return be16_to_cpu(st->rx_buf[0]);
>>> +}
>>> +
>>> +static int ad7923_read_raw(struct iio_dev *indio_dev,
>>> +               struct iio_chan_spec const *chan,
>>> +               int *val,
>>> +               int *val2,
>>> +               long m)
>>> +{
>>> +    int ret;
>>> +    struct ad7923_state *st = iio_priv(indio_dev);
>>> +
>>> +    switch (m) {
>>> +    case IIO_CHAN_INFO_RAW:
>>> +        mutex_lock(&indio_dev->mlock);
>>> +        if (iio_buffer_enabled(indio_dev))
>>> +            ret = -EBUSY;
>>> +        else
>>> +            ret = ad7923_scan_direct(st, chan->address);
>>> +        mutex_unlock(&indio_dev->mlock);
>>> +
>>> +        if (ret < 0)
>>> +            return ret;
>>> +
>>> +        if (chan->address == EXTRACT(ret, 12, 4))
>>> +            *val = EXTRACT(ret, 0, 12);
>>> +
>>> +        return IIO_VAL_INT;
>>> +    }
>>> +    return -EINVAL;
>>> +}
>>> +
>>> +static const struct iio_info ad7923_info = {
>>> +    .read_raw = &ad7923_read_raw,
>>> +    .update_scan_mode = ad7923_update_scan_mode,
>>> +    .driver_module = THIS_MODULE,
>>> +};
>>> +
>>> +static int ad7923_probe(struct spi_device *spi)
>>> +{
>>> +    struct ad7923_state *st;
>>> +    struct iio_dev *indio_dev = iio_device_alloc(sizeof(*st));
>>> +    int ret;
>>> +
>>> +    if (indio_dev == NULL)
>>> +        return -ENOMEM;
>>> +
>>> +    st = iio_priv(indio_dev);
>>> +
>>> +    spi_set_drvdata(spi, indio_dev);
>>> +
>>> +    st->spi = spi;
>>> +
>>> +    indio_dev->name = spi_get_device_id(spi)->name;
>>> +    indio_dev->dev.parent = &spi->dev;
>>> +    indio_dev->modes = INDIO_DIRECT_MODE;
>>> +    indio_dev->channels = ad7923_channels;
>>> +    indio_dev->num_channels = ARRAY_SIZE(ad7923_channels);
>>> +    indio_dev->info = &ad7923_info;
>>> +
>>> +    /* Setup default message */
>>> +
>>> +    st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
>>> +    st->scan_single_xfer[0].len = 2;
>>> +    st->scan_single_xfer[0].cs_change = 1;
>>> +    st->scan_single_xfer[1].rx_buf = &st->rx_buf[0];
>>> +    st->scan_single_xfer[1].len = 2;
>>> +
>>> +    spi_message_init(&st->scan_single_msg);
>>> +    spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
>>> +    spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
>>> +
>>> +    ret = iio_triggered_buffer_setup(indio_dev, NULL,
>>> +            &ad7923_trigger_handler, NULL);
>>> +    if (ret)
>>> +        goto error_free;
>>> +
>>> +    ret = iio_device_register(indio_dev);
>>> +    if (ret)
>>> +        goto error_cleanup_ring;
>>> +
>>> +    return 0;
>>> +
>>> +error_cleanup_ring:
>>> +    iio_triggered_buffer_cleanup(indio_dev);
>>> +error_free:
>>> +    iio_device_free(indio_dev);
>>> +
>>> +    return ret;
>>> +}
>>> +
>>> +static int ad7923_remove(struct spi_device *spi)
>>> +{
>>> +    struct iio_dev *indio_dev = spi_get_drvdata(spi);
>>> +
>>> +    iio_device_unregister(indio_dev);
>>> +    iio_triggered_buffer_cleanup(indio_dev);
>>> +    iio_device_free(indio_dev);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static const struct spi_device_id ad7923_id[] = {
>>> +    {"ad7923", 0},
>>> +    {}
>>> +};
>>> +MODULE_DEVICE_TABLE(spi, ad7923_id);
>>> +
>>> +static struct spi_driver ad7923_driver = {
>>> +    .driver = {
>>> +        .name    = "ad7923",
>>> +        .owner    = THIS_MODULE,
>>> +    },
>>> +    .probe        = ad7923_probe,
>>> +    .remove        = ad7923_remove,
>>> +    .id_table    = ad7923_id,
>>> +};
>>> +module_spi_driver(ad7923_driver);
>>> +
>>> +MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
>>> +MODULE_AUTHOR("Patrick Vasseur <patrick.vasseur@c-s.fr>");
>>> +MODULE_DESCRIPTION("Analog Devices AD7923 ADC");
>>> +MODULE_LICENSE("GPL v2");
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