diff options
| -rw-r--r-- | drivers/iio/accel/adxl345.h | 1 | ||||
| -rw-r--r-- | drivers/iio/accel/adxl345_core.c | 11 | ||||
| -rw-r--r-- | drivers/iio/accel/adxl345_i2c.c | 2 | ||||
| -rw-r--r-- | drivers/iio/accel/adxl345_spi.c | 7 |
4 files changed, 18 insertions, 3 deletions
diff --git a/drivers/iio/accel/adxl345.h b/drivers/iio/accel/adxl345.h index 3d5c8719db3d..6f39f16d3e08 100644 --- a/drivers/iio/accel/adxl345.h +++ b/drivers/iio/accel/adxl345.h @@ -62,6 +62,7 @@ struct adxl345_chip_info { }; int adxl345_core_probe(struct device *dev, struct regmap *regmap, + 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 11fdb21d5477..58892c66429e 100644 --- a/drivers/iio/accel/adxl345_core.c +++ b/drivers/iio/accel/adxl345_core.c @@ -25,6 +25,7 @@ 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; }; @@ -196,12 +197,21 @@ static const struct iio_info adxl345_info = { * 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_state *st; @@ -222,6 +232,7 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap, st->info = device_get_match_data(dev); if (!st->info) return -ENODEV; + st->fifo_delay = fifo_delay_default; indio_dev->name = st->info->name; indio_dev->info = &adxl345_info; diff --git a/drivers/iio/accel/adxl345_i2c.c b/drivers/iio/accel/adxl345_i2c.c index cb23fb11fcd7..8c385dd6c01d 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, NULL); + return adxl345_core_probe(&client->dev, regmap, 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 968e7b390d4b..7e518aea17bf 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, @@ -28,6 +29,7 @@ static int adxl345_spi_setup(struct device *dev, struct regmap *regmap) static int adxl345_spi_probe(struct spi_device *spi) { struct regmap *regmap; + bool needs_delay; /* Bail out if max_speed_hz exceeds 5 MHz */ if (spi->max_speed_hz > ADXL345_MAX_SPI_FREQ_HZ) @@ -38,10 +40,11 @@ static int adxl345_spi_probe(struct spi_device *spi) if (IS_ERR(regmap)) return dev_err_probe(&spi->dev, PTR_ERR(regmap), "Error initializing regmap\n"); + needs_delay = spi->max_speed_hz > ADXL345_MAX_FREQ_NO_FIFO_DELAY; if (spi->mode & SPI_3WIRE) - return adxl345_core_probe(&spi->dev, regmap, adxl345_spi_setup); + return adxl345_core_probe(&spi->dev, regmap, needs_delay, adxl345_spi_setup); else - return adxl345_core_probe(&spi->dev, regmap, NULL); + return adxl345_core_probe(&spi->dev, regmap, needs_delay, NULL); } static const struct adxl345_chip_info adxl345_spi_info = { |