1 files changed, 379 insertions, 38 deletions

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index b1efab0f6404..d1b2d3985a40 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -7,6 +7,8 @@
  * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf
  */
 
+#include <linux/bitfield.h>
+#include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
@@ -14,36 +16,92 @@
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/kfifo_buf.h>
 
 #include "adxl345.h"
 
-struct adxl345_data {
+#define ADXL345_FIFO_BYPASS	0
+#define ADXL345_FIFO_FIFO	1
+#define ADXL345_FIFO_STREAM	2
+
+#define ADXL345_DIRS 3
+
+#define ADXL345_INT_NONE		0xff
+#define ADXL345_INT1			0
+#define ADXL345_INT2			1
+
+struct adxl345_state {
 	const struct adxl345_chip_info *info;
 	struct regmap *regmap;
+	bool fifo_delay; /* delay: delay is needed for SPI */
+	int irq;
+	u8 intio;
+	u8 int_map;
+	u8 watermark;
+	u8 fifo_mode;
+	__le16 fifo_buf[ADXL345_DIRS * ADXL345_FIFO_SIZE + 1] __aligned(IIO_DMA_MINALIGN);
 };
 
-#define ADXL345_CHANNEL(index, axis) {					\
+#define ADXL345_CHANNEL(index, reg, axis) {					\
 	.type = IIO_ACCEL,						\
 	.modified = 1,							\
 	.channel2 = IIO_MOD_##axis,					\
-	.address = index,						\
+	.address = (reg),						\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |			\
 		BIT(IIO_CHAN_INFO_CALIBBIAS),				\
 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |		\
 		BIT(IIO_CHAN_INFO_SAMP_FREQ),				\
+	.scan_index = (index),				\
+	.scan_type = {					\
+		.sign = 's',				\
+		.realbits = 13,				\
+		.storagebits = 16,			\
+		.endianness = IIO_LE,			\
+	},						\
 }
 
+enum adxl345_chans {
+	chan_x, chan_y, chan_z,
+};
+
 static const struct iio_chan_spec adxl345_channels[] = {
-	ADXL345_CHANNEL(0, X),
-	ADXL345_CHANNEL(1, Y),
-	ADXL345_CHANNEL(2, Z),
+	ADXL345_CHANNEL(0, chan_x, X),
+	ADXL345_CHANNEL(1, chan_y, Y),
+	ADXL345_CHANNEL(2, chan_z, Z),
 };
 
+static const unsigned long adxl345_scan_masks[] = {
+	BIT(chan_x) | BIT(chan_y) | BIT(chan_z),
+	0
+};
+
+static int adxl345_set_interrupts(struct adxl345_state *st)
+{
+	int ret;
+	unsigned int int_enable = st->int_map;
+	unsigned int int_map;
+
+	/*
+	 * Any bits set to 0 in the INT map register send their respective
+	 * interrupts to the INT1 pin, whereas bits set to 1 send their respective
+	 * interrupts to the INT2 pin. The intio shall convert this accordingly.
+	 */
+	int_map = FIELD_GET(ADXL345_REG_INT_SOURCE_MSK,
+			    st->intio ? st->int_map : ~st->int_map);
+
+	ret = regmap_write(st->regmap, ADXL345_REG_INT_MAP, int_map);
+	if (ret)
+		return ret;
+
+	return regmap_write(st->regmap, ADXL345_REG_INT_ENABLE, int_enable);
+}
+
 static int adxl345_read_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *chan,
 			    int *val, int *val2, long mask)
 {
-	struct adxl345_data *data = iio_priv(indio_dev);
+	struct adxl345_state *st = iio_priv(indio_dev);
 	__le16 accel;
 	long long samp_freq_nhz;
 	unsigned int regval;
@@ -56,7 +114,7 @@ static int adxl345_read_raw(struct iio_dev *indio_dev,
 		 * ADXL345_REG_DATA(X0/Y0/Z0) contain the least significant byte
 		 * and ADXL345_REG_DATA(X0/Y0/Z0) + 1 the most significant byte
 		 */
-		ret = regmap_bulk_read(data->regmap,
+		ret = regmap_bulk_read(st->regmap,
 				       ADXL345_REG_DATA_AXIS(chan->address),
 				       &accel, sizeof(accel));
 		if (ret < 0)
@@ -66,10 +124,10 @@ static int adxl345_read_raw(struct iio_dev *indio_dev,
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		*val = 0;
-		*val2 = data->info->uscale;
+		*val2 = st->info->uscale;
 		return IIO_VAL_INT_PLUS_MICRO;
 	case IIO_CHAN_INFO_CALIBBIAS:
-		ret = regmap_read(data->regmap,
+		ret = regmap_read(st->regmap,
 				  ADXL345_REG_OFS_AXIS(chan->address), &regval);
 		if (ret < 0)
 			return ret;
@@ -81,7 +139,7 @@ static int adxl345_read_raw(struct iio_dev *indio_dev,
 
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SAMP_FREQ:
-		ret = regmap_read(data->regmap, ADXL345_REG_BW_RATE, &regval);
+		ret = regmap_read(st->regmap, ADXL345_REG_BW_RATE, &regval);
 		if (ret < 0)
 			return ret;
 
@@ -99,7 +157,7 @@ static int adxl345_write_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan,
 			     int val, int val2, long mask)
 {
-	struct adxl345_data *data = iio_priv(indio_dev);
+	struct adxl345_state *st = iio_priv(indio_dev);
 	s64 n;
 
 	switch (mask) {
@@ -108,14 +166,14 @@ static int adxl345_write_raw(struct iio_dev *indio_dev,
 		 * 8-bit resolution at +/- 2g, that is 4x accel data scale
 		 * factor
 		 */
-		return regmap_write(data->regmap,
+		return regmap_write(st->regmap,
 				    ADXL345_REG_OFS_AXIS(chan->address),
 				    val / 4);
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		n = div_s64(val * NANOHZ_PER_HZ + val2,
 			    ADXL345_BASE_RATE_NANO_HZ);
 
-		return regmap_update_bits(data->regmap, ADXL345_REG_BW_RATE,
+		return regmap_update_bits(st->regmap, ADXL345_REG_BW_RATE,
 					  ADXL345_BW_RATE,
 					  clamp_val(ilog2(n), 0,
 						    ADXL345_BW_RATE));
@@ -124,6 +182,24 @@ static int adxl345_write_raw(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
+static int adxl345_set_watermark(struct iio_dev *indio_dev, unsigned int value)
+{
+	struct adxl345_state *st = iio_priv(indio_dev);
+	unsigned int fifo_mask = 0x1F;
+	int ret;
+
+	value = min(value, ADXL345_FIFO_SIZE - 1);
+
+	ret = regmap_update_bits(st->regmap, ADXL345_REG_FIFO_CTL, fifo_mask, value);
+	if (ret)
+		return ret;
+
+	st->watermark = value;
+	st->int_map |= ADXL345_INT_WATERMARK;
+
+	return 0;
+}
+
 static int adxl345_write_raw_get_fmt(struct iio_dev *indio_dev,
 				     struct iio_chan_spec const *chan,
 				     long mask)
@@ -138,6 +214,33 @@ static int adxl345_write_raw_get_fmt(struct iio_dev *indio_dev,
 	}
 }
 
+/**
+ * adxl345_set_measure_en() - Enable and disable measuring.
+ *
+ * @st: The device data.
+ * @en: Enable measurements, else standby mode.
+ *
+ * For lowest power operation, standby mode can be used. In standby mode,
+ * current consumption is supposed to be reduced to 0.1uA (typical). In this
+ * mode no measurements are made. Placing the device into standby mode
+ * preserves the contents of FIFO.
+ *
+ * Return: Returns 0 if successful, or a negative error value.
+ */
+static int adxl345_set_measure_en(struct adxl345_state *st, bool en)
+{
+	unsigned int val = en ? ADXL345_POWER_CTL_MEASURE : ADXL345_POWER_CTL_STANDBY;
+
+	return regmap_write(st->regmap, ADXL345_REG_POWER_CTL, val);
+}
+
+static void adxl345_powerdown(void *ptr)
+{
+	struct adxl345_state *st = ptr;
+
+	adxl345_set_measure_en(st, false);
+}
+
 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(
 "0.09765625 0.1953125 0.390625 0.78125 1.5625 3.125 6.25 12.5 25 50 100 200 400 800 1600 3200"
 );
@@ -151,37 +254,244 @@ static const struct attribute_group adxl345_attrs_group = {
 	.attrs = adxl345_attrs,
 };
 
-static const struct iio_info adxl345_info = {
-	.attrs		= &adxl345_attrs_group,
-	.read_raw	= adxl345_read_raw,
-	.write_raw	= adxl345_write_raw,
-	.write_raw_get_fmt	= adxl345_write_raw_get_fmt,
+static int adxl345_set_fifo(struct adxl345_state *st)
+{
+	int ret;
+
+	/* FIFO should only be configured while in standby mode */
+	ret = adxl345_set_measure_en(st, false);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(st->regmap, ADXL345_REG_FIFO_CTL,
+			   FIELD_PREP(ADXL345_FIFO_CTL_SAMPLES_MSK,
+				      st->watermark) |
+			   FIELD_PREP(ADXL345_FIFO_CTL_TRIGGER_MSK,
+				      st->intio) |
+			   FIELD_PREP(ADXL345_FIFO_CTL_MODE_MSK,
+				      st->fifo_mode));
+	if (ret < 0)
+		return ret;
+
+	return adxl345_set_measure_en(st, true);
+}
+
+/**
+ * adxl345_get_samples() - Read number of FIFO entries.
+ * @st: The initialized state instance of this driver.
+ *
+ * The sensor does not support treating any axis individually, or exclude them
+ * from measuring.
+ *
+ * Return: negative error, or value.
+ */
+static int adxl345_get_samples(struct adxl345_state *st)
+{
+	unsigned int regval = 0;
+	int ret;
+
+	ret = regmap_read(st->regmap, ADXL345_REG_FIFO_STATUS, &regval);
+	if (ret < 0)
+		return ret;
+
+	return FIELD_GET(ADXL345_REG_FIFO_STATUS_MSK, regval);
+}
+
+/**
+ * adxl345_fifo_transfer() - Read samples number of elements.
+ * @st: The instance of the state object of this sensor.
+ * @samples: The number of lines in the FIFO referred to as fifo_entry.
+ *
+ * It is recommended that a multiple-byte read of all registers be performed to
+ * prevent a change in data between reads of sequential registers. That is to
+ * read out the data registers X0, X1, Y0, Y1, Z0, Z1, i.e. 6 bytes at once.
+ *
+ * Return: 0 or error value.
+ */
+static int adxl345_fifo_transfer(struct adxl345_state *st, int samples)
+{
+	size_t count;
+	int i, ret = 0;
+
+	/* count is the 3x the fifo_buf element size, hence 6B */
+	count = sizeof(st->fifo_buf[0]) * ADXL345_DIRS;
+	for (i = 0; i < samples; i++) {
+		/* read 3x 2 byte elements from base address into next fifo_buf position */
+		ret = regmap_bulk_read(st->regmap, ADXL345_REG_XYZ_BASE,
+				       st->fifo_buf + (i * count / 2), count);
+		if (ret < 0)
+			return ret;
+
+		/*
+		 * To ensure that the FIFO has completely popped, there must be at least 5
+		 * us between the end of reading the data registers, signified by the
+		 * transition to register 0x38 from 0x37 or the CS pin going high, and the
+		 * start of new reads of the FIFO or reading the FIFO_STATUS register. For
+		 * SPI operation at 1.5 MHz or lower, the register addressing portion of the
+		 * transmission is sufficient delay to ensure the FIFO has completely
+		 * popped. It is necessary for SPI operation greater than 1.5 MHz to
+		 * de-assert the CS pin to ensure a total of 5 us, which is at most 3.4 us
+		 * at 5 MHz operation.
+		 */
+		if (st->fifo_delay && samples > 1)
+			udelay(3);
+	}
+	return ret;
+}
+
+/**
+ * adxl345_fifo_reset() - Empty the FIFO in error condition.
+ * @st: The instance to the state object of the sensor.
+ *
+ * Read all elements of the FIFO. Reading the interrupt source register
+ * resets the sensor.
+ */
+static void adxl345_fifo_reset(struct adxl345_state *st)
+{
+	int regval;
+	int samples;
+
+	adxl345_set_measure_en(st, false);
+
+	samples = adxl345_get_samples(st);
+	if (samples > 0)
+		adxl345_fifo_transfer(st, samples);
+
+	regmap_read(st->regmap, ADXL345_REG_INT_SOURCE, &regval);
+
+	adxl345_set_measure_en(st, true);
+}
+
+static int adxl345_buffer_postenable(struct iio_dev *indio_dev)
+{
+	struct adxl345_state *st = iio_priv(indio_dev);
+	int ret;
+
+	ret = adxl345_set_interrupts(st);
+	if (ret < 0)
+		return ret;
+
+	st->fifo_mode = ADXL345_FIFO_STREAM;
+	return adxl345_set_fifo(st);
+}
+
+static int adxl345_buffer_predisable(struct iio_dev *indio_dev)
+{
+	struct adxl345_state *st = iio_priv(indio_dev);
+	int ret;
+
+	st->fifo_mode = ADXL345_FIFO_BYPASS;
+	ret = adxl345_set_fifo(st);
+	if (ret < 0)
+		return ret;
+
+	st->int_map = 0x00;
+	return adxl345_set_interrupts(st);
+}
+
+static const struct iio_buffer_setup_ops adxl345_buffer_ops = {
+	.postenable = adxl345_buffer_postenable,
+	.predisable = adxl345_buffer_predisable,
 };
 
-static int adxl345_powerup(void *regmap)
+static int adxl345_get_status(struct adxl345_state *st)
 {
-	return regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_MEASURE);
+	int ret;
+	unsigned int regval;
+
+	ret = regmap_read(st->regmap, ADXL345_REG_INT_SOURCE, &regval);
+	if (ret < 0)
+		return ret;
+
+	return FIELD_GET(ADXL345_REG_INT_SOURCE_MSK, regval);
 }
 
-static void adxl345_powerdown(void *regmap)
+static int adxl345_fifo_push(struct iio_dev *indio_dev,
+			     int samples)
 {
-	regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_STANDBY);
+	struct adxl345_state *st = iio_priv(indio_dev);
+	int i, ret;
+
+	if (samples <= 0)
+		return -EINVAL;
+
+	ret = adxl345_fifo_transfer(st, samples);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < ADXL345_DIRS * samples; i += ADXL345_DIRS)
+		iio_push_to_buffers(indio_dev, &st->fifo_buf[i]);
+
+	return 0;
+}
+
+/**
+ * adxl345_irq_handler() - Handle irqs of the ADXL345.
+ * @irq: The irq being handled.
+ * @p: The struct iio_device pointer for the device.
+ *
+ * Return: The interrupt was handled.
+ */
+static irqreturn_t adxl345_irq_handler(int irq, void *p)
+{
+	struct iio_dev *indio_dev = p;
+	struct adxl345_state *st = iio_priv(indio_dev);
+	int int_stat;
+	int samples;
+
+	int_stat = adxl345_get_status(st);
+	if (int_stat <= 0)
+		return IRQ_NONE;
+
+	if (int_stat & ADXL345_INT_OVERRUN)
+		goto err;
+
+	if (int_stat & ADXL345_INT_WATERMARK) {
+		samples = adxl345_get_samples(st);
+		if (samples < 0)
+			goto err;
+
+		if (adxl345_fifo_push(indio_dev, samples) < 0)
+			goto err;
+	}
+	return IRQ_HANDLED;
+
+err:
+	adxl345_fifo_reset(st);
+
+	return IRQ_HANDLED;
 }
 
+static const struct iio_info adxl345_info = {
+	.attrs		= &adxl345_attrs_group,
+	.read_raw	= adxl345_read_raw,
+	.write_raw	= adxl345_write_raw,
+	.write_raw_get_fmt	= adxl345_write_raw_get_fmt,
+	.hwfifo_set_watermark = adxl345_set_watermark,
+};
+
 /**
- * adxl345_core_probe() - probe and setup for the adxl345 accelerometer,
- *                        also covers the adlx375 accelerometer
+ * adxl345_core_probe() - Probe and setup for the accelerometer.
  * @dev:	Driver model representation of the device
  * @regmap:	Regmap instance for the device
+ * @fifo_delay_default: Using FIFO with SPI needs delay
  * @setup:	Setup routine to be executed right before the standard device
  *		setup
  *
+ * For SPI operation greater than 1.6 MHz, it is necessary to deassert the CS
+ * pin to ensure a total delay of 5 us; otherwise, the delay is not sufficient.
+ * The total delay necessary for 5 MHz operation is at most 3.4 us. This is not
+ * a concern when using I2C mode because the communication rate is low enough
+ * to ensure a sufficient delay between FIFO reads.
+ * Ref: "Retrieving Data from FIFO", p. 21 of 36, Data Sheet ADXL345 Rev. G
+ *
  * Return: 0 on success, negative errno on error
  */
 int adxl345_core_probe(struct device *dev, struct regmap *regmap,
+		       bool fifo_delay_default,
 		       int (*setup)(struct device*, struct regmap*))
 {
-	struct adxl345_data *data;
+	struct adxl345_state *st;
 	struct iio_dev *indio_dev;
 	u32 regval;
 	unsigned int data_format_mask = (ADXL345_DATA_FORMAT_RANGE |
@@ -190,30 +500,32 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 					 ADXL345_DATA_FORMAT_SELF_TEST);
 	int ret;
 
-	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
 	if (!indio_dev)
 		return -ENOMEM;
 
-	data = iio_priv(indio_dev);
-	data->regmap = regmap;
-	data->info = device_get_match_data(dev);
-	if (!data->info)
+	st = iio_priv(indio_dev);
+	st->regmap = regmap;
+	st->info = device_get_match_data(dev);
+	if (!st->info)
 		return -ENODEV;
+	st->fifo_delay = fifo_delay_default;
 
-	indio_dev->name = data->info->name;
+	indio_dev->name = st->info->name;
 	indio_dev->info = &adxl345_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = adxl345_channels;
 	indio_dev->num_channels = ARRAY_SIZE(adxl345_channels);
+	indio_dev->available_scan_masks = adxl345_scan_masks;
 
 	if (setup) {
 		/* Perform optional initial bus specific configuration */
-		ret = setup(dev, data->regmap);
+		ret = setup(dev, st->regmap);
 		if (ret)
 			return ret;
 
 		/* Enable full-resolution mode */
-		ret = regmap_update_bits(data->regmap, ADXL345_REG_DATA_FORMAT,
+		ret = regmap_update_bits(st->regmap, ADXL345_REG_DATA_FORMAT,
 					 data_format_mask,
 					 ADXL345_DATA_FORMAT_FULL_RES);
 		if (ret)
@@ -222,14 +534,14 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 
 	} else {
 		/* Enable full-resolution mode (init all data_format bits) */
-		ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT,
+		ret = regmap_write(st->regmap, ADXL345_REG_DATA_FORMAT,
 				   ADXL345_DATA_FORMAT_FULL_RES);
 		if (ret)
 			return dev_err_probe(dev, ret,
 					     "Failed to set data range\n");
 	}
 
-	ret = regmap_read(data->regmap, ADXL345_REG_DEVID, &regval);
+	ret = regmap_read(st->regmap, ADXL345_REG_DEVID, &regval);
 	if (ret < 0)
 		return dev_err_probe(dev, ret, "Error reading device ID\n");
 
@@ -238,14 +550,43 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 				     regval, ADXL345_DEVID);
 
 	/* Enable measurement mode */
-	ret = adxl345_powerup(data->regmap);
+	ret = adxl345_set_measure_en(st, true);
 	if (ret < 0)
 		return dev_err_probe(dev, ret, "Failed to enable measurement mode\n");
 
-	ret = devm_add_action_or_reset(dev, adxl345_powerdown, data->regmap);
+	ret = devm_add_action_or_reset(dev, adxl345_powerdown, st);
 	if (ret < 0)
 		return ret;
 
+	st->intio = ADXL345_INT1;
+	st->irq = fwnode_irq_get_byname(dev_fwnode(dev), "INT1");
+	if (st->irq < 0) {
+		st->intio = ADXL345_INT2;
+		st->irq = fwnode_irq_get_byname(dev_fwnode(dev), "INT2");
+		if (st->irq < 0)
+			st->intio = ADXL345_INT_NONE;
+	}
+
+	if (st->intio != ADXL345_INT_NONE) {
+		/* FIFO_STREAM mode is going to be activated later */
+		ret = devm_iio_kfifo_buffer_setup(dev, indio_dev, &adxl345_buffer_ops);
+		if (ret)
+			return ret;
+
+		ret = devm_request_threaded_irq(dev, st->irq, NULL,
+						&adxl345_irq_handler,
+						IRQF_SHARED | IRQF_ONESHOT,
+						indio_dev->name, indio_dev);
+		if (ret)
+			return ret;
+	} else {
+		ret = regmap_write(st->regmap, ADXL345_REG_FIFO_CTL,
+				   FIELD_PREP(ADXL345_FIFO_CTL_MODE_MSK,
+					      ADXL345_FIFO_BYPASS));
+		if (ret < 0)
+			return ret;
+	}
+
 	return devm_iio_device_register(dev, indio_dev);
 }
 EXPORT_SYMBOL_NS_GPL(adxl345_core_probe, "IIO_ADXL345");