text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * BMA220 Digital triaxial acceleration sensor driver
   *
   * Copyright (c) 2016,2020 Intel Corporation.
   */
  
  #include <linux/bits.h>
  #include <linux/kernel.h>
  #include <linux/mod_devicetable.h>
  #include <linux/module.h>
  #include <linux/spi/spi.h>
  
  #include <linux/iio/buffer.h>
  #include <linux/iio/iio.h>
  #include <linux/iio/sysfs.h>
  #include <linux/iio/trigger_consumer.h>
  #include <linux/iio/triggered_buffer.h>
  
  #define BMA220_REG_ID				0x00
  #define BMA220_REG_ACCEL_X			0x02
  #define BMA220_REG_ACCEL_Y			0x03
  #define BMA220_REG_ACCEL_Z			0x04
  #define BMA220_REG_RANGE			0x11
  #define BMA220_REG_SUSPEND			0x18
  
  #define BMA220_CHIP_ID				0xDD
  #define BMA220_READ_MASK			BIT(7)
  #define BMA220_RANGE_MASK			GENMASK(1, 0)
  #define BMA220_DATA_SHIFT			2
  #define BMA220_SUSPEND_SLEEP			0xFF
  #define BMA220_SUSPEND_WAKE			0x00
  
  #define BMA220_DEVICE_NAME			"bma220"
  
  #define BMA220_ACCEL_CHANNEL(index, reg, axis) {			\
  	.type = IIO_ACCEL,						\
  	.address = reg,							\
  	.modified = 1,							\
  	.channel2 = IIO_MOD_##axis,					\
  	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),			\
  	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),		\
  	.scan_index = index,						\
  	.scan_type = {							\
  		.sign = 's',						\
  		.realbits = 6,						\
  		.storagebits = 8,					\
  		.shift = BMA220_DATA_SHIFT,				\
  		.endianness = IIO_CPU,					\
  	},								\
  }
  
  enum bma220_axis {
  	AXIS_X,
  	AXIS_Y,
  	AXIS_Z,
  };
  
  static const int bma220_scale_table[][2] = {
  	{0, 623000}, {1, 248000}, {2, 491000}, {4, 983000},
  };
  
  struct bma220_data {
  	struct spi_device *spi_device;
  	struct mutex lock;
  	struct {
  		s8 chans[3];
  		/* Ensure timestamp is naturally aligned. */
  		s64 timestamp __aligned(8);
  	} scan;
  	u8 tx_buf[2] ____cacheline_aligned;
  };
  
  static const struct iio_chan_spec bma220_channels[] = {
  	BMA220_ACCEL_CHANNEL(0, BMA220_REG_ACCEL_X, X),
  	BMA220_ACCEL_CHANNEL(1, BMA220_REG_ACCEL_Y, Y),
  	BMA220_ACCEL_CHANNEL(2, BMA220_REG_ACCEL_Z, Z),
  	IIO_CHAN_SOFT_TIMESTAMP(3),
  };
  
  static inline int bma220_read_reg(struct spi_device *spi, u8 reg)
  {
  	return spi_w8r8(spi, reg | BMA220_READ_MASK);
  }
  
  static const unsigned long bma220_accel_scan_masks[] = {
  	BIT(AXIS_X) | BIT(AXIS_Y) | BIT(AXIS_Z),
  	0
  };
  
  static irqreturn_t bma220_trigger_handler(int irq, void *p)
  {
  	int ret;
  	struct iio_poll_func *pf = p;
  	struct iio_dev *indio_dev = pf->indio_dev;
  	struct bma220_data *data = iio_priv(indio_dev);
  	struct spi_device *spi = data->spi_device;
  
  	mutex_lock(&data->lock);
  	data->tx_buf[0] = BMA220_REG_ACCEL_X | BMA220_READ_MASK;
  	ret = spi_write_then_read(spi, data->tx_buf, 1, &data->scan.chans,
  				  ARRAY_SIZE(bma220_channels) - 1);
  	if (ret < 0)
  		goto err;
  
  	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
  					   pf->timestamp);
  err:
  	mutex_unlock(&data->lock);
  	iio_trigger_notify_done(indio_dev->trig);
  
  	return IRQ_HANDLED;
  }
  
  static int bma220_read_raw(struct iio_dev *indio_dev,
  			   struct iio_chan_spec const *chan,
  			   int *val, int *val2, long mask)
  {
  	int ret;
  	u8 range_idx;
  	struct bma220_data *data = iio_priv(indio_dev);
  
  	switch (mask) {
  	case IIO_CHAN_INFO_RAW:
  		ret = bma220_read_reg(data->spi_device, chan->address);
  		if (ret < 0)
  			return -EINVAL;
  		*val = sign_extend32(ret >> BMA220_DATA_SHIFT, 5);
  		return IIO_VAL_INT;
  	case IIO_CHAN_INFO_SCALE:
  		ret = bma220_read_reg(data->spi_device, BMA220_REG_RANGE);
  		if (ret < 0)
  			return ret;
  		range_idx = ret & BMA220_RANGE_MASK;
  		*val = bma220_scale_table[range_idx][0];
  		*val2 = bma220_scale_table[range_idx][1];
  		return IIO_VAL_INT_PLUS_MICRO;
  	}
  
  	return -EINVAL;
  }
  
  static int bma220_write_raw(struct iio_dev *indio_dev,
  			    struct iio_chan_spec const *chan,
  			    int val, int val2, long mask)
  {
  	int i;
  	int ret;
  	int index = -1;
  	struct bma220_data *data = iio_priv(indio_dev);
  
  	switch (mask) {
  	case IIO_CHAN_INFO_SCALE:
  		for (i = 0; i < ARRAY_SIZE(bma220_scale_table); i++)
  			if (val == bma220_scale_table[i][0] &&
  			    val2 == bma220_scale_table[i][1]) {
  				index = i;
  				break;
  			}
  		if (index < 0)
  			return -EINVAL;
  
  		mutex_lock(&data->lock);
  		data->tx_buf[0] = BMA220_REG_RANGE;
  		data->tx_buf[1] = index;
  		ret = spi_write(data->spi_device, data->tx_buf,
  				sizeof(data->tx_buf));
  		if (ret < 0)
  			dev_err(&data->spi_device->dev,
  				"failed to set measurement range\n");
  		mutex_unlock(&data->lock);
  
  		return 0;
  	}
  
  	return -EINVAL;
  }
  
  static int bma220_read_avail(struct iio_dev *indio_dev,
  			     struct iio_chan_spec const *chan,
  			     const int **vals, int *type, int *length,
  			     long mask)
  {
  	switch (mask) {
  	case IIO_CHAN_INFO_SCALE:
  		*vals = (int *)bma220_scale_table;
  		*type = IIO_VAL_INT_PLUS_MICRO;
  		*length = ARRAY_SIZE(bma220_scale_table) * 2;
  		return IIO_AVAIL_LIST;
  	default:
  		return -EINVAL;
  	}
  }
  
  static const struct iio_info bma220_info = {
  	.read_raw		= bma220_read_raw,
  	.write_raw		= bma220_write_raw,
  	.read_avail		= bma220_read_avail,
  };
  
  static int bma220_init(struct spi_device *spi)
  {
  	int ret;
  
  	ret = bma220_read_reg(spi, BMA220_REG_ID);
  	if (ret != BMA220_CHIP_ID)
  		return -ENODEV;
  
  	/* Make sure the chip is powered on */
  	ret = bma220_read_reg(spi, BMA220_REG_SUSPEND);
  	if (ret == BMA220_SUSPEND_WAKE)
  		ret = bma220_read_reg(spi, BMA220_REG_SUSPEND);
  	if (ret < 0)
  		return ret;
  	if (ret == BMA220_SUSPEND_WAKE)
  		return -EBUSY;
  
  	return 0;
  }
  
  static int bma220_deinit(struct spi_device *spi)
  {
  	int ret;
  
  	/* Make sure the chip is powered off */
  	ret = bma220_read_reg(spi, BMA220_REG_SUSPEND);
  	if (ret == BMA220_SUSPEND_SLEEP)
  		ret = bma220_read_reg(spi, BMA220_REG_SUSPEND);
  	if (ret < 0)
  		return ret;
  	if (ret == BMA220_SUSPEND_SLEEP)
  		return -EBUSY;
  
  	return 0;
  }
  
  static int bma220_probe(struct spi_device *spi)
  {
  	int ret;
  	struct iio_dev *indio_dev;
  	struct bma220_data *data;
  
  	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
  	if (!indio_dev) {
  		dev_err(&spi->dev, "iio allocation failed!\n");
  		return -ENOMEM;
  	}
  
  	data = iio_priv(indio_dev);
  	data->spi_device = spi;
  	spi_set_drvdata(spi, indio_dev);
  	mutex_init(&data->lock);
  
  	indio_dev->info = &bma220_info;
  	indio_dev->name = BMA220_DEVICE_NAME;
  	indio_dev->modes = INDIO_DIRECT_MODE;
  	indio_dev->channels = bma220_channels;
  	indio_dev->num_channels = ARRAY_SIZE(bma220_channels);
  	indio_dev->available_scan_masks = bma220_accel_scan_masks;
  
  	ret = bma220_init(data->spi_device);
  	if (ret)
  		return ret;
  
  	ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
  					 bma220_trigger_handler, NULL);
  	if (ret < 0) {
  		dev_err(&spi->dev, "iio triggered buffer setup failed\n");
  		goto err_suspend;
  	}
  
  	ret = iio_device_register(indio_dev);
  	if (ret < 0) {
  		dev_err(&spi->dev, "iio_device_register failed\n");
  		iio_triggered_buffer_cleanup(indio_dev);
  		goto err_suspend;
  	}
  
  	return 0;
  
  err_suspend:
  	return bma220_deinit(spi);
  }
  
  static int bma220_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);
  
  	return bma220_deinit(spi);
  }
  
  static __maybe_unused int bma220_suspend(struct device *dev)
  {
  	struct bma220_data *data = iio_priv(dev_get_drvdata(dev));
  
  	/* The chip can be suspended/woken up by a simple register read. */
  	return bma220_read_reg(data->spi_device, BMA220_REG_SUSPEND);
  }
  
  static __maybe_unused int bma220_resume(struct device *dev)
  {
  	struct bma220_data *data = iio_priv(dev_get_drvdata(dev));
  
  	return bma220_read_reg(data->spi_device, BMA220_REG_SUSPEND);
  }
  static SIMPLE_DEV_PM_OPS(bma220_pm_ops, bma220_suspend, bma220_resume);
  
  static const struct spi_device_id bma220_spi_id[] = {
  	{"bma220", 0},
  	{}
  };
  
  static const struct acpi_device_id bma220_acpi_id[] = {
  	{"BMA0220", 0},
  	{}
  };
  MODULE_DEVICE_TABLE(spi, bma220_spi_id);
  
  static struct spi_driver bma220_driver = {
  	.driver = {
  		.name = "bma220_spi",
  		.pm = &bma220_pm_ops,
  		.acpi_match_table = bma220_acpi_id,
  	},
  	.probe =            bma220_probe,
  	.remove =           bma220_remove,
  	.id_table =         bma220_spi_id,
  };
  module_spi_driver(bma220_driver);
  
  MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
  MODULE_DESCRIPTION("BMA220 acceleration sensor driver");
  MODULE_LICENSE("GPL v2");
  