IIO ADC support for AD7923 (0eac259d) · Commits · e / devices / android_kernel_xiaomi_markw

drivers/iio/adc/Kconfig

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		@@ -30,6 +30,18 @@ config AD7298
		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

drivers/iio/adc/Makefile

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		@@ -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

drivers/iio/adc/ad7923.c

0 → 100644

+298 −0

Original line number	Diff line number	Diff line
		/*
		* 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");