[mirror_ubuntu-bionic-kernel.git] / drivers / iio / imu / st_lsm6dsx / st_lsm6dsx_buffer.c

/*
 * STMicroelectronics st_lsm6dsx FIFO buffer library driver
 *
 * LSM6DS3/LSM6DSM: The FIFO buffer can be configured to store data
 * from gyroscope and accelerometer. Samples are queued without any tag
 * according to a specific pattern based on 'FIFO data sets' (6 bytes each):
 *  - 1st data set is reserved for gyroscope data
 *  - 2nd data set is reserved for accelerometer data
 * The FIFO pattern changes depending on the ODRs and decimation factors
 * assigned to the FIFO data sets. The first sequence of data stored in FIFO
 * buffer contains the data of all the enabled FIFO data sets
 * (e.g. Gx, Gy, Gz, Ax, Ay, Az), then data are repeated depending on the
 * value of the decimation factor and ODR set for each FIFO data set.
 * FIFO supported modes:
 *  - BYPASS: FIFO disabled
 *  - CONTINUOUS: FIFO enabled. When the buffer is full, the FIFO index
 *    restarts from the beginning and the oldest sample is overwritten
 *
 * Copyright 2016 STMicroelectronics Inc.
 *
 * Lorenzo Bianconi <lorenzo.bianconi@st.com>
 * Denis Ciocca <denis.ciocca@st.com>
 *
 * Licensed under the GPL-2.
 */
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>

#include "st_lsm6dsx.h"

#define ST_LSM6DSX_REG_FIFO_THL_ADDR		0x06
#define ST_LSM6DSX_REG_FIFO_THH_ADDR		0x07
#define ST_LSM6DSX_FIFO_TH_MASK			GENMASK(11, 0)
#define ST_LSM6DSX_REG_FIFO_DEC_GXL_ADDR	0x08
#define ST_LSM6DSX_REG_FIFO_MODE_ADDR		0x0a
#define ST_LSM6DSX_FIFO_MODE_MASK		GENMASK(2, 0)
#define ST_LSM6DSX_FIFO_ODR_MASK		GENMASK(6, 3)
#define ST_LSM6DSX_REG_FIFO_DIFFL_ADDR		0x3a
#define ST_LSM6DSX_FIFO_DIFF_MASK		GENMASK(11, 0)
#define ST_LSM6DSX_FIFO_EMPTY_MASK		BIT(12)
#define ST_LSM6DSX_REG_FIFO_OUTL_ADDR		0x3e

#define ST_LSM6DSX_MAX_FIFO_ODR_VAL		0x08

struct st_lsm6dsx_decimator_entry {
	u8 decimator;
	u8 val;
};

static const
struct st_lsm6dsx_decimator_entry st_lsm6dsx_decimator_table[] = {
	{  0, 0x0 },
	{  1, 0x1 },
	{  2, 0x2 },
	{  3, 0x3 },
	{  4, 0x4 },
	{  8, 0x5 },
	{ 16, 0x6 },
	{ 32, 0x7 },
};

static int st_lsm6dsx_get_decimator_val(u8 val)
{
	const int max_size = ARRAY_SIZE(st_lsm6dsx_decimator_table);
	int i;

	for (i = 0; i < max_size; i++)
		if (st_lsm6dsx_decimator_table[i].decimator == val)
			break;

	return i == max_size ? 0 : st_lsm6dsx_decimator_table[i].val;
}

static void st_lsm6dsx_get_max_min_odr(struct st_lsm6dsx_hw *hw,
				       u16 *max_odr, u16 *min_odr)
{
	struct st_lsm6dsx_sensor *sensor;
	int i;

	*max_odr = 0, *min_odr = ~0;
	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
		sensor = iio_priv(hw->iio_devs[i]);

		if (!(hw->enable_mask & BIT(sensor->id)))
			continue;

		*max_odr = max_t(u16, *max_odr, sensor->odr);
		*min_odr = min_t(u16, *min_odr, sensor->odr);
	}
}

static int st_lsm6dsx_update_decimators(struct st_lsm6dsx_hw *hw)
{
	struct st_lsm6dsx_sensor *sensor;
	u16 max_odr, min_odr, sip = 0;
	int err, i;
	u8 data;

	st_lsm6dsx_get_max_min_odr(hw, &max_odr, &min_odr);

	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
		sensor = iio_priv(hw->iio_devs[i]);

		/* update fifo decimators and sample in pattern */
		if (hw->enable_mask & BIT(sensor->id)) {
			sensor->sip = sensor->odr / min_odr;
			sensor->decimator = max_odr / sensor->odr;
			data = st_lsm6dsx_get_decimator_val(sensor->decimator);
		} else {
			sensor->sip = 0;
			sensor->decimator = 0;
			data = 0;
		}

		err = st_lsm6dsx_write_with_mask(hw,
					ST_LSM6DSX_REG_FIFO_DEC_GXL_ADDR,
					sensor->decimator_mask, data);
		if (err < 0)
			return err;

		sip += sensor->sip;
	}
	hw->sip = sip;

	return 0;
}

static int st_lsm6dsx_set_fifo_mode(struct st_lsm6dsx_hw *hw,
				    enum st_lsm6dsx_fifo_mode fifo_mode)
{
	u8 data;
	int err;

	switch (fifo_mode) {
	case ST_LSM6DSX_FIFO_BYPASS:
		data = fifo_mode;
		break;
	case ST_LSM6DSX_FIFO_CONT:
		data = (ST_LSM6DSX_MAX_FIFO_ODR_VAL <<
			__ffs(ST_LSM6DSX_FIFO_ODR_MASK)) | fifo_mode;
		break;
	default:
		return -EINVAL;
	}

	err = hw->tf->write(hw->dev, ST_LSM6DSX_REG_FIFO_MODE_ADDR,
			    sizeof(data), &data);
	if (err < 0)
		return err;

	hw->fifo_mode = fifo_mode;

	return 0;
}

int st_lsm6dsx_update_watermark(struct st_lsm6dsx_sensor *sensor, u16 watermark)
{
	u16 fifo_watermark = ~0, cur_watermark, sip = 0;
	struct st_lsm6dsx_hw *hw = sensor->hw;
	struct st_lsm6dsx_sensor *cur_sensor;
	__le16 wdata;
	int i, err;
	u8 data;

	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
		cur_sensor = iio_priv(hw->iio_devs[i]);

		if (!(hw->enable_mask & BIT(cur_sensor->id)))
			continue;

		cur_watermark = (cur_sensor == sensor) ? watermark
						       : cur_sensor->watermark;

		fifo_watermark = min_t(u16, fifo_watermark, cur_watermark);
		sip += cur_sensor->sip;
	}

	if (!sip)
		return 0;

	fifo_watermark = max_t(u16, fifo_watermark, sip);
	fifo_watermark = (fifo_watermark / sip) * sip;
	fifo_watermark = fifo_watermark * ST_LSM6DSX_SAMPLE_DEPTH;

	mutex_lock(&hw->lock);

	err = hw->tf->read(hw->dev, ST_LSM6DSX_REG_FIFO_THH_ADDR,
			   sizeof(data), &data);
	if (err < 0)
		goto out;

	fifo_watermark = ((data << 8) & ~ST_LSM6DSX_FIFO_TH_MASK) |
			 (fifo_watermark & ST_LSM6DSX_FIFO_TH_MASK);

	wdata = cpu_to_le16(fifo_watermark);
	err = hw->tf->write(hw->dev, ST_LSM6DSX_REG_FIFO_THL_ADDR,
			    sizeof(wdata), (u8 *)&wdata);
out:
	mutex_unlock(&hw->lock);

	return err < 0 ? err : 0;
}

/**
 * st_lsm6dsx_read_fifo() - LSM6DS3-LSM6DSM read FIFO routine
 * @hw: Pointer to instance of struct st_lsm6dsx_hw.
 *
 * Read samples from the hw FIFO and push them to IIO buffers.
 *
 * Return: Number of bytes read from the FIFO
 */
static int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
{
	u16 fifo_len, pattern_len = hw->sip * ST_LSM6DSX_SAMPLE_SIZE;
	int err, acc_sip, gyro_sip, read_len, samples, offset;
	struct st_lsm6dsx_sensor *acc_sensor, *gyro_sensor;
	s64 acc_ts, acc_delta_ts, gyro_ts, gyro_delta_ts;
	u8 iio_buff[ALIGN(ST_LSM6DSX_SAMPLE_SIZE, sizeof(s64)) + sizeof(s64)];
	u8 buff[pattern_len];
	__le16 fifo_status;

	err = hw->tf->read(hw->dev, ST_LSM6DSX_REG_FIFO_DIFFL_ADDR,
			   sizeof(fifo_status), (u8 *)&fifo_status);
	if (err < 0)
		return err;

	if (fifo_status & cpu_to_le16(ST_LSM6DSX_FIFO_EMPTY_MASK))
		return 0;

	fifo_len = (le16_to_cpu(fifo_status) & ST_LSM6DSX_FIFO_DIFF_MASK) *
		   ST_LSM6DSX_CHAN_SIZE;
	samples = fifo_len / ST_LSM6DSX_SAMPLE_SIZE;
	fifo_len = (fifo_len / pattern_len) * pattern_len;

	/*
	 * compute delta timestamp between two consecutive samples
	 * in order to estimate queueing time of data generated
	 * by the sensor
	 */
	acc_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]);
	acc_ts = acc_sensor->ts - acc_sensor->delta_ts;
	acc_delta_ts = div_s64(acc_sensor->delta_ts * acc_sensor->decimator,
			       samples);

	gyro_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_GYRO]);
	gyro_ts = gyro_sensor->ts - gyro_sensor->delta_ts;
	gyro_delta_ts = div_s64(gyro_sensor->delta_ts * gyro_sensor->decimator,
				samples);

	for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
		err = hw->tf->read(hw->dev, ST_LSM6DSX_REG_FIFO_OUTL_ADDR,
				   sizeof(buff), buff);
		if (err < 0)
			return err;

		/*
		 * Data are written to the FIFO with a specific pattern
		 * depending on the configured ODRs. The first sequence of data
		 * stored in FIFO contains the data of all enabled sensors
		 * (e.g. Gx, Gy, Gz, Ax, Ay, Az), then data are repeated
		 * depending on the value of the decimation factor set for each
		 * sensor.
		 *
		 * Supposing the FIFO is storing data from gyroscope and
		 * accelerometer at different ODRs:
		 *   - gyroscope ODR = 208Hz, accelerometer ODR = 104Hz
		 * Since the gyroscope ODR is twice the accelerometer one, the
		 * following pattern is repeated every 9 samples:
		 *   - Gx, Gy, Gz, Ax, Ay, Az, Gx, Gy, Gz
		 */
		gyro_sip = gyro_sensor->sip;
		acc_sip = acc_sensor->sip;
		offset = 0;

		while (acc_sip > 0 || gyro_sip > 0) {
			if (gyro_sip-- > 0) {
				memcpy(iio_buff, &buff[offset],
				       ST_LSM6DSX_SAMPLE_SIZE);
				iio_push_to_buffers_with_timestamp(
					hw->iio_devs[ST_LSM6DSX_ID_GYRO],
					iio_buff, gyro_ts);
				offset += ST_LSM6DSX_SAMPLE_SIZE;
				gyro_ts += gyro_delta_ts;
			}

			if (acc_sip-- > 0) {
				memcpy(iio_buff, &buff[offset],
				       ST_LSM6DSX_SAMPLE_SIZE);
				iio_push_to_buffers_with_timestamp(
					hw->iio_devs[ST_LSM6DSX_ID_ACC],
					iio_buff, acc_ts);
				offset += ST_LSM6DSX_SAMPLE_SIZE;
				acc_ts += acc_delta_ts;
			}
		}
	}

	return read_len;
}

static int st_lsm6dsx_flush_fifo(struct st_lsm6dsx_hw *hw)
{
	int err;

	mutex_lock(&hw->fifo_lock);

	st_lsm6dsx_read_fifo(hw);
	err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_BYPASS);

	mutex_unlock(&hw->fifo_lock);

	return err;
}

static int st_lsm6dsx_update_fifo(struct iio_dev *iio_dev, bool enable)
{
	struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
	struct st_lsm6dsx_hw *hw = sensor->hw;
	int err;

	if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS) {
		err = st_lsm6dsx_flush_fifo(hw);
		if (err < 0)
			return err;
	}

	if (enable) {
		err = st_lsm6dsx_sensor_enable(sensor);
		if (err < 0)
			return err;
	} else {
		err = st_lsm6dsx_sensor_disable(sensor);
		if (err < 0)
			return err;
	}

	err = st_lsm6dsx_update_decimators(hw);
	if (err < 0)
		return err;

	err = st_lsm6dsx_update_watermark(sensor, sensor->watermark);
	if (err < 0)
		return err;

	if (hw->enable_mask) {
		err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT);
		if (err < 0)
			return err;

		/*
		 * store enable buffer timestamp as reference to compute
		 * first delta timestamp
		 */
		sensor->ts = iio_get_time_ns(iio_dev);
	}

	return 0;
}

static irqreturn_t st_lsm6dsx_handler_irq(int irq, void *private)
{
	struct st_lsm6dsx_hw *hw = (struct st_lsm6dsx_hw *)private;
	struct st_lsm6dsx_sensor *sensor;
	int i;

	if (!hw->sip)
		return IRQ_NONE;

	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
		sensor = iio_priv(hw->iio_devs[i]);

		if (sensor->sip > 0) {
			s64 timestamp;

			timestamp = iio_get_time_ns(hw->iio_devs[i]);
			sensor->delta_ts = timestamp - sensor->ts;
			sensor->ts = timestamp;
		}
	}

	return IRQ_WAKE_THREAD;
}

static irqreturn_t st_lsm6dsx_handler_thread(int irq, void *private)
{
	struct st_lsm6dsx_hw *hw = (struct st_lsm6dsx_hw *)private;
	int count;

	mutex_lock(&hw->fifo_lock);
	count = st_lsm6dsx_read_fifo(hw);
	mutex_unlock(&hw->fifo_lock);

	return !count ? IRQ_NONE : IRQ_HANDLED;
}

static int st_lsm6dsx_buffer_preenable(struct iio_dev *iio_dev)
{
	return st_lsm6dsx_update_fifo(iio_dev, true);
}

static int st_lsm6dsx_buffer_postdisable(struct iio_dev *iio_dev)
{
	return st_lsm6dsx_update_fifo(iio_dev, false);
}

static const struct iio_buffer_setup_ops st_lsm6dsx_buffer_ops = {
	.preenable = st_lsm6dsx_buffer_preenable,
	.postdisable = st_lsm6dsx_buffer_postdisable,
};

int st_lsm6dsx_fifo_setup(struct st_lsm6dsx_hw *hw)
{
	struct iio_buffer *buffer;
	unsigned long irq_type;
	int i, err;

	irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq));

	switch (irq_type) {
	case IRQF_TRIGGER_HIGH:
	case IRQF_TRIGGER_RISING:
		break;
	default:
		dev_info(hw->dev, "mode %lx unsupported\n", irq_type);
		return -EINVAL;
	}

	err = devm_request_threaded_irq(hw->dev, hw->irq,
					st_lsm6dsx_handler_irq,
					st_lsm6dsx_handler_thread,
					irq_type | IRQF_ONESHOT,
					"lsm6dsx", hw);
	if (err) {
		dev_err(hw->dev, "failed to request trigger irq %d\n",
			hw->irq);
		return err;
	}

	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
		buffer = devm_iio_kfifo_allocate(hw->dev);
		if (!buffer)
			return -ENOMEM;

		iio_device_attach_buffer(hw->iio_devs[i], buffer);
		hw->iio_devs[i]->modes |= INDIO_BUFFER_SOFTWARE;
		hw->iio_devs[i]->setup_ops = &st_lsm6dsx_buffer_ops;
	}

	return 0;
}
Commit	Line	Data
290a6ce1 LB	1	/*
	2	* STMicroelectronics st_lsm6dsx FIFO buffer library driver
	3	*
	4	* LSM6DS3/LSM6DSM: The FIFO buffer can be configured to store data
	5	* from gyroscope and accelerometer. Samples are queued without any tag
	6	* according to a specific pattern based on 'FIFO data sets' (6 bytes each):
	7	* - 1st data set is reserved for gyroscope data
	8	* - 2nd data set is reserved for accelerometer data
	9	* The FIFO pattern changes depending on the ODRs and decimation factors
	10	* assigned to the FIFO data sets. The first sequence of data stored in FIFO
	11	* buffer contains the data of all the enabled FIFO data sets
	12	* (e.g. Gx, Gy, Gz, Ax, Ay, Az), then data are repeated depending on the
	13	* value of the decimation factor and ODR set for each FIFO data set.
	14	* FIFO supported modes:
	15	* - BYPASS: FIFO disabled
	16	* - CONTINUOUS: FIFO enabled. When the buffer is full, the FIFO index
	17	* restarts from the beginning and the oldest sample is overwritten
	18	*
	19	* Copyright 2016 STMicroelectronics Inc.
	20	*
	21	* Lorenzo Bianconi <lorenzo.bianconi@st.com>
	22	* Denis Ciocca <denis.ciocca@st.com>
	23	*
	24	* Licensed under the GPL-2.
	25	*/
	26	#include <linux/module.h>
	27	#include <linux/interrupt.h>
	28	#include <linux/irq.h>
	29	#include <linux/iio/kfifo_buf.h>
	30	#include <linux/iio/iio.h>
	31	#include <linux/iio/buffer.h>
	32
	33	#include "st_lsm6dsx.h"
	34
	35	#define ST_LSM6DSX_REG_FIFO_THL_ADDR 0x06
	36	#define ST_LSM6DSX_REG_FIFO_THH_ADDR 0x07
	37	#define ST_LSM6DSX_FIFO_TH_MASK GENMASK(11, 0)
	38	#define ST_LSM6DSX_REG_FIFO_DEC_GXL_ADDR 0x08
	39	#define ST_LSM6DSX_REG_FIFO_MODE_ADDR 0x0a
	40	#define ST_LSM6DSX_FIFO_MODE_MASK GENMASK(2, 0)
	41	#define ST_LSM6DSX_FIFO_ODR_MASK GENMASK(6, 3)
	42	#define ST_LSM6DSX_REG_FIFO_DIFFL_ADDR 0x3a
	43	#define ST_LSM6DSX_FIFO_DIFF_MASK GENMASK(11, 0)
	44	#define ST_LSM6DSX_FIFO_EMPTY_MASK BIT(12)
	45	#define ST_LSM6DSX_REG_FIFO_OUTL_ADDR 0x3e
	46
	47	#define ST_LSM6DSX_MAX_FIFO_ODR_VAL 0x08
	48
	49	struct st_lsm6dsx_decimator_entry {
	50	u8 decimator;
	51	u8 val;
	52	};
	53
	54	static const
	55	struct st_lsm6dsx_decimator_entry st_lsm6dsx_decimator_table[] = {
	56	{ 0, 0x0 },
	57	{ 1, 0x1 },
	58	{ 2, 0x2 },
	59	{ 3, 0x3 },
	60	{ 4, 0x4 },
	61	{ 8, 0x5 },
	62	{ 16, 0x6 },
	63	{ 32, 0x7 },
	64	};
65
66	static int st_lsm6dsx_get_decimator_val(u8 val)
67	{
68	const int max_size = ARRAY_SIZE(st_lsm6dsx_decimator_table);
69	int i;
70
71	for (i = 0; i < max_size; i++)
72	if (st_lsm6dsx_decimator_table[i].decimator == val)
73	break;
74
75	return i == max_size ? 0 : st_lsm6dsx_decimator_table[i].val;
76	}
77
78	static void st_lsm6dsx_get_max_min_odr(struct st_lsm6dsx_hw *hw,
79	u16 max_odr, u16 min_odr)
80	{
81	struct st_lsm6dsx_sensor *sensor;
82	int i;
83
84	max_odr = 0, min_odr = ~0;
85	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
86	sensor = iio_priv(hw->iio_devs[i]);
87
88	if (!(hw->enable_mask & BIT(sensor->id)))
89	continue;
90
91	max_odr = max_t(u16, max_odr, sensor->odr);
92	min_odr = min_t(u16, min_odr, sensor->odr);
93	}
94	}
95
96	static int st_lsm6dsx_update_decimators(struct st_lsm6dsx_hw *hw)
97	{
98	struct st_lsm6dsx_sensor *sensor;
99	u16 max_odr, min_odr, sip = 0;
100	int err, i;
101	u8 data;
102
103	st_lsm6dsx_get_max_min_odr(hw, &max_odr, &min_odr);
104
105	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
106	sensor = iio_priv(hw->iio_devs[i]);
107
108	/* update fifo decimators and sample in pattern */
109	if (hw->enable_mask & BIT(sensor->id)) {
110	sensor->sip = sensor->odr / min_odr;
111	sensor->decimator = max_odr / sensor->odr;
112	data = st_lsm6dsx_get_decimator_val(sensor->decimator);
113	} else {
114	sensor->sip = 0;
115	sensor->decimator = 0;
116	data = 0;
117	}
118
119	err = st_lsm6dsx_write_with_mask(hw,
120	ST_LSM6DSX_REG_FIFO_DEC_GXL_ADDR,
121	sensor->decimator_mask, data);
122	if (err < 0)
123	return err;
124
125	sip += sensor->sip;
126	}
127	hw->sip = sip;
128
129	return 0;
130	}
131
132	static int st_lsm6dsx_set_fifo_mode(struct st_lsm6dsx_hw *hw,
133	enum st_lsm6dsx_fifo_mode fifo_mode)
134	{
135	u8 data;
136	int err;
137
138	switch (fifo_mode) {
139	case ST_LSM6DSX_FIFO_BYPASS:
140	data = fifo_mode;
141	break;
142	case ST_LSM6DSX_FIFO_CONT:
143	data = (ST_LSM6DSX_MAX_FIFO_ODR_VAL <<
144	__ffs(ST_LSM6DSX_FIFO_ODR_MASK)) \| fifo_mode;
145	break;
146	default:
147	return -EINVAL;
148	}
149
150	err = hw->tf->write(hw->dev, ST_LSM6DSX_REG_FIFO_MODE_ADDR,
151	sizeof(data), &data);
152	if (err < 0)
153	return err;
154
155	hw->fifo_mode = fifo_mode;
156
157	return 0;
158	}
159
160	int st_lsm6dsx_update_watermark(struct st_lsm6dsx_sensor *sensor, u16 watermark)
161	{
162	u16 fifo_watermark = ~0, cur_watermark, sip = 0;
163	struct st_lsm6dsx_hw *hw = sensor->hw;
164	struct st_lsm6dsx_sensor *cur_sensor;
165	__le16 wdata;
166	int i, err;
167	u8 data;
168
169	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
170	cur_sensor = iio_priv(hw->iio_devs[i]);
171
172	if (!(hw->enable_mask & BIT(cur_sensor->id)))
173	continue;
174
175	cur_watermark = (cur_sensor == sensor) ? watermark
176	: cur_sensor->watermark;
177
178	fifo_watermark = min_t(u16, fifo_watermark, cur_watermark);
179	sip += cur_sensor->sip;
180	}
181
182	if (!sip)
183	return 0;
184
185	fifo_watermark = max_t(u16, fifo_watermark, sip);
186	fifo_watermark = (fifo_watermark / sip) * sip;
187	fifo_watermark = fifo_watermark * ST_LSM6DSX_SAMPLE_DEPTH;
188
189	mutex_lock(&hw->lock);
190
191	err = hw->tf->read(hw->dev, ST_LSM6DSX_REG_FIFO_THH_ADDR,
192	sizeof(data), &data);
193	if (err < 0)
194	goto out;
195
6985bd5e LB	196	fifo_watermark = ((data << 8) & ~ST_LSM6DSX_FIFO_TH_MASK) \|
6985bd5e LB	197	(fifo_watermark & ST_LSM6DSX_FIFO_TH_MASK);
290a6ce1 LB	198
	199	wdata = cpu_to_le16(fifo_watermark);
	200	err = hw->tf->write(hw->dev, ST_LSM6DSX_REG_FIFO_THL_ADDR,
	201	sizeof(wdata), (u8 *)&wdata);
	202	out:
	203	mutex_unlock(&hw->lock);
	204
	205	return err < 0 ? err : 0;
	206	}
	207
	208	/**
	209	* st_lsm6dsx_read_fifo() - LSM6DS3-LSM6DSM read FIFO routine
	210	* @hw: Pointer to instance of struct st_lsm6dsx_hw.
	211	*
	212	* Read samples from the hw FIFO and push them to IIO buffers.
	213	*
	214	* Return: Number of bytes read from the FIFO
	215	*/
	216	static int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
	217	{
	218	u16 fifo_len, pattern_len = hw->sip * ST_LSM6DSX_SAMPLE_SIZE;
	219	int err, acc_sip, gyro_sip, read_len, samples, offset;
	220	struct st_lsm6dsx_sensor acc_sensor, gyro_sensor;
	221	s64 acc_ts, acc_delta_ts, gyro_ts, gyro_delta_ts;
	222	u8 iio_buff[ALIGN(ST_LSM6DSX_SAMPLE_SIZE, sizeof(s64)) + sizeof(s64)];
	223	u8 buff[pattern_len];
	224	__le16 fifo_status;
	225
	226	err = hw->tf->read(hw->dev, ST_LSM6DSX_REG_FIFO_DIFFL_ADDR,
	227	sizeof(fifo_status), (u8 *)&fifo_status);
	228	if (err < 0)
	229	return err;
	230
	231	if (fifo_status & cpu_to_le16(ST_LSM6DSX_FIFO_EMPTY_MASK))
	232	return 0;
	233
	234	fifo_len = (le16_to_cpu(fifo_status) & ST_LSM6DSX_FIFO_DIFF_MASK) *
	235	ST_LSM6DSX_CHAN_SIZE;
	236	samples = fifo_len / ST_LSM6DSX_SAMPLE_SIZE;
	237	fifo_len = (fifo_len / pattern_len) * pattern_len;
	238
	239	/*
	240	* compute delta timestamp between two consecutive samples
	241	* in order to estimate queueing time of data generated
	242	* by the sensor
	243	*/
	244	acc_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]);
	245	acc_ts = acc_sensor->ts - acc_sensor->delta_ts;
	246	acc_delta_ts = div_s64(acc_sensor->delta_ts * acc_sensor->decimator,
	247	samples);
	248
	249	gyro_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_GYRO]);
	250	gyro_ts = gyro_sensor->ts - gyro_sensor->delta_ts;
	251	gyro_delta_ts = div_s64(gyro_sensor->delta_ts * gyro_sensor->decimator,
	252	samples);
	253
	254	for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
	255	err = hw->tf->read(hw->dev, ST_LSM6DSX_REG_FIFO_OUTL_ADDR,
	256	sizeof(buff), buff);
	257	if (err < 0)
	258	return err;
	259
	260	/*
	261	* Data are written to the FIFO with a specific pattern
262	* depending on the configured ODRs. The first sequence of data
263	* stored in FIFO contains the data of all enabled sensors
264	* (e.g. Gx, Gy, Gz, Ax, Ay, Az), then data are repeated
265	* depending on the value of the decimation factor set for each
266	* sensor.
267	*
268	* Supposing the FIFO is storing data from gyroscope and
269	* accelerometer at different ODRs:
270	* - gyroscope ODR = 208Hz, accelerometer ODR = 104Hz
271	* Since the gyroscope ODR is twice the accelerometer one, the
272	* following pattern is repeated every 9 samples:
273	* - Gx, Gy, Gz, Ax, Ay, Az, Gx, Gy, Gz
274	*/
275	gyro_sip = gyro_sensor->sip;
276	acc_sip = acc_sensor->sip;
277	offset = 0;
278
279	while (acc_sip > 0 \|\| gyro_sip > 0) {
280	if (gyro_sip-- > 0) {
281	memcpy(iio_buff, &buff[offset],
282	ST_LSM6DSX_SAMPLE_SIZE);
283	iio_push_to_buffers_with_timestamp(
284	hw->iio_devs[ST_LSM6DSX_ID_GYRO],
285	iio_buff, gyro_ts);
286	offset += ST_LSM6DSX_SAMPLE_SIZE;
287	gyro_ts += gyro_delta_ts;
288	}
289
290	if (acc_sip-- > 0) {
291	memcpy(iio_buff, &buff[offset],
292	ST_LSM6DSX_SAMPLE_SIZE);
293	iio_push_to_buffers_with_timestamp(
294	hw->iio_devs[ST_LSM6DSX_ID_ACC],
295	iio_buff, acc_ts);
296	offset += ST_LSM6DSX_SAMPLE_SIZE;
297	acc_ts += acc_delta_ts;
298	}
299	}
300	}
301
302	return read_len;
303	}
304
305	static int st_lsm6dsx_flush_fifo(struct st_lsm6dsx_hw *hw)
306	{
307	int err;
308
309	mutex_lock(&hw->fifo_lock);
310
311	st_lsm6dsx_read_fifo(hw);
312	err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_BYPASS);
313
314	mutex_unlock(&hw->fifo_lock);
315
316	return err;
317	}
318
319	static int st_lsm6dsx_update_fifo(struct iio_dev *iio_dev, bool enable)
320	{
321	struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
322	struct st_lsm6dsx_hw *hw = sensor->hw;
323	int err;
324
325	if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS) {
326	err = st_lsm6dsx_flush_fifo(hw);
327	if (err < 0)
328	return err;
329	}
330
331	if (enable) {
332	err = st_lsm6dsx_sensor_enable(sensor);
333	if (err < 0)
334	return err;
335	} else {
336	err = st_lsm6dsx_sensor_disable(sensor);
337	if (err < 0)
338	return err;
339	}
340
341	err = st_lsm6dsx_update_decimators(hw);
342	if (err < 0)
343	return err;
344
345	err = st_lsm6dsx_update_watermark(sensor, sensor->watermark);
346	if (err < 0)
347	return err;
348
349	if (hw->enable_mask) {
350	err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT);
351	if (err < 0)
352	return err;
353
354	/*
355	* store enable buffer timestamp as reference to compute
356	* first delta timestamp
357	*/
358	sensor->ts = iio_get_time_ns(iio_dev);
359	}
360
361	return 0;
362	}
363
364	static irqreturn_t st_lsm6dsx_handler_irq(int irq, void *private)
365	{
366	struct st_lsm6dsx_hw hw = (struct st_lsm6dsx_hw )private;
367	struct st_lsm6dsx_sensor *sensor;
368	int i;
369
370	if (!hw->sip)
371	return IRQ_NONE;
372
373	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
374	sensor = iio_priv(hw->iio_devs[i]);
375
376	if (sensor->sip > 0) {
377	s64 timestamp;
378
379	timestamp = iio_get_time_ns(hw->iio_devs[i]);
380	sensor->delta_ts = timestamp - sensor->ts;
381	sensor->ts = timestamp;
382	}
383	}
384
385	return IRQ_WAKE_THREAD;
386	}
387
388	static irqreturn_t st_lsm6dsx_handler_thread(int irq, void *private)
389	{
390	struct st_lsm6dsx_hw hw = (struct st_lsm6dsx_hw )private;
391	int count;
392
393	mutex_lock(&hw->fifo_lock);
394	count = st_lsm6dsx_read_fifo(hw);
395	mutex_unlock(&hw->fifo_lock);
396
397	return !count ? IRQ_NONE : IRQ_HANDLED;
398	}
399
400	static int st_lsm6dsx_buffer_preenable(struct iio_dev *iio_dev)
401	{
402	return st_lsm6dsx_update_fifo(iio_dev, true);
403	}
404
405	static int st_lsm6dsx_buffer_postdisable(struct iio_dev *iio_dev)
406	{
407	return st_lsm6dsx_update_fifo(iio_dev, false);
408	}
409
410	static const struct iio_buffer_setup_ops st_lsm6dsx_buffer_ops = {
411	.preenable = st_lsm6dsx_buffer_preenable,
412	.postdisable = st_lsm6dsx_buffer_postdisable,
413	};
414
415	int st_lsm6dsx_fifo_setup(struct st_lsm6dsx_hw *hw)
416	{
417	struct iio_buffer *buffer;
418	unsigned long irq_type;
419	int i, err;
420
421	irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq));
422
423	switch (irq_type) {
424	case IRQF_TRIGGER_HIGH:
425	case IRQF_TRIGGER_RISING:
426	break;
427	default:
428	dev_info(hw->dev, "mode %lx unsupported\n", irq_type);
429	return -EINVAL;
430	}
431
432	err = devm_request_threaded_irq(hw->dev, hw->irq,
433	st_lsm6dsx_handler_irq,
434	st_lsm6dsx_handler_thread,
435	irq_type \| IRQF_ONESHOT,
436	"lsm6dsx", hw);
437	if (err) {
438	dev_err(hw->dev, "failed to request trigger irq %d\n",
439	hw->irq);
440	return err;
441	}
442
443	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
444	buffer = devm_iio_kfifo_allocate(hw->dev);
445	if (!buffer)
446	return -ENOMEM;
447
448	iio_device_attach_buffer(hw->iio_devs[i], buffer);
449	hw->iio_devs[i]->modes \|= INDIO_BUFFER_SOFTWARE;
450	hw->iio_devs[i]->setup_ops = &st_lsm6dsx_buffer_ops;
451	}
452
453	return 0;
454	}