Add the possibility to delay FIFO access when SPI is used. According to
the datasheet this is needed for the adxl345. When initialization
happens over SPI the need for delay is to be signalized, and the delay
will be used.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/iio/accel/adxl345.h      | 2 +-
 drivers/iio/accel/adxl345_core.c | 6 +++++-
 drivers/iio/accel/adxl345_i2c.c  | 2 +-
 drivers/iio/accel/adxl345_spi.c  | 3 +++
 4 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/accel/adxl345.h b/drivers/iio/accel/adxl345.h
index cf4132715c..4ba493f636 100644
--- a/drivers/iio/accel/adxl345.h
+++ b/drivers/iio/accel/adxl345.h
@@ -62,7 +62,7 @@ struct adxl345_chip_info {
 };
 
 int adxl345_core_probe(struct device *dev, struct regmap *regmap,
-		       int irq,
+		       int irq, bool fifo_delay_default,
 		       int (*setup)(struct device*, struct regmap*));
 
 #endif /* _ADXL345_H_ */
diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 57bc530cc3..ef3b7d9fb4 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -22,6 +22,7 @@ struct adxl34x_state {
 	int irq;
 	const struct adxl345_chip_info *info;
 	struct regmap *regmap;
+	bool fifo_delay; /* delay: delay is needed for SPI */
 };
 
 #define ADXL345_CHANNEL(index, axis) {					\
@@ -197,13 +198,14 @@ static const struct iio_info adxl345_info = {
  * @dev:	Driver model representation of the device
  * @regmap:	Regmap instance for the device
  * @irq:	Interrupt handling for async usage
+ * @fifo_delay_default: Using FIFO with SPI needs delay
  * @setup:	Setup routine to be executed right before the standard device
  *		setup
  *
  * Return: 0 on success, negative errno on error
  */
 int adxl345_core_probe(struct device *dev, struct regmap *regmap,
-		       int irq,
+		       int irq, bool fifo_delay_default,
 		       int (*setup)(struct device*, struct regmap*))
 {
 	struct adxl34x_state *st;
@@ -232,6 +234,8 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 	if (!st->info)
 		return -ENODEV;
 
+	st->fifo_delay = fifo_delay_default;
+
 	indio_dev->name = st->info->name;
 	indio_dev->info = &adxl345_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
diff --git a/drivers/iio/accel/adxl345_i2c.c b/drivers/iio/accel/adxl345_i2c.c
index 604b706c29..fa1b7e7026 100644
--- a/drivers/iio/accel/adxl345_i2c.c
+++ b/drivers/iio/accel/adxl345_i2c.c
@@ -27,7 +27,7 @@ static int adxl345_i2c_probe(struct i2c_client *client)
 	if (IS_ERR(regmap))
 		return dev_err_probe(&client->dev, PTR_ERR(regmap), "Error initializing regmap\n");
 
-	return adxl345_core_probe(&client->dev, regmap, client->irq, NULL);
+	return adxl345_core_probe(&client->dev, regmap, client->irq, false, NULL);
 }
 
 static const struct adxl345_chip_info adxl345_i2c_info = {
diff --git a/drivers/iio/accel/adxl345_spi.c b/drivers/iio/accel/adxl345_spi.c
index 39e7d71e1d..75940d9c1c 100644
--- a/drivers/iio/accel/adxl345_spi.c
+++ b/drivers/iio/accel/adxl345_spi.c
@@ -12,6 +12,7 @@
 #include "adxl345.h"
 
 #define ADXL345_MAX_SPI_FREQ_HZ		5000000
+#define ADXL345_MAX_FREQ_NO_FIFO_DELAY	1500000
 
 static const struct regmap_config adxl345_spi_regmap_config = {
 	.reg_bits = 8,
@@ -41,10 +42,12 @@ static int adxl345_spi_probe(struct spi_device *spi)
 	if (spi->mode & SPI_3WIRE)
 		return adxl345_core_probe(&spi->dev, regmap,
 					  spi->irq,
+					  spi->max_speed_hz > ADXL345_MAX_FREQ_NO_FIFO_DELAY,
 					  adxl345_spi_setup);
 	else
 		return adxl345_core_probe(&spi->dev, regmap,
 					  spi->irq,
+					  spi->max_speed_hz > ADXL345_MAX_FREQ_NO_FIFO_DELAY,
 					  NULL);
 }
 
-- 
2.39.2