From 7ba8a04dcdfb5ebcb4985a92dfc4dc4f59510464 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Wed, 16 Jan 2013 12:48:00 +0000 Subject: iio:adis16400: Add support for the 52.85 Hz base sampling rate The adis16400 and similar have two different base sampling rate available, from which the actual sampling rate is derived. 1638 Hz and 52.85 Hz, switching to the lower base sampling rate allows to support lower sampling rates. This patch adds support for switching to the lower base sampling rate if the requested sampling frequency is outside of the range which can be supported by the higher base sampling rate. The function which is used to read the current sampling rate already has support for the lower sampling rate, so no changes are required there. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- drivers/iio/imu/adis16400_core.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'drivers/iio') diff --git a/drivers/iio/imu/adis16400_core.c b/drivers/iio/imu/adis16400_core.c index 8551fde90563..58699ac22d02 100644 --- a/drivers/iio/imu/adis16400_core.c +++ b/drivers/iio/imu/adis16400_core.c @@ -92,18 +92,26 @@ static int adis16400_get_freq(struct adis16400_state *st) static int adis16400_set_freq(struct adis16400_state *st, unsigned int freq) { unsigned int t; + uint8_t val = 0; t = 1638404 / freq; - if (t > 0) + if (t >= 128) { + val |= ADIS16400_SMPL_PRD_TIME_BASE; + t = 52851 / freq; + if (t >= 128) + t = 127; + } else if (t != 0) { t--; - t &= ADIS16400_SMPL_PRD_DIV_MASK; + } + + val |= t; - if ((t & ADIS16400_SMPL_PRD_DIV_MASK) >= 0x0A) + if (t >= 0x0A || (val & ADIS16400_SMPL_PRD_TIME_BASE)) st->adis.spi->max_speed_hz = ADIS16400_SPI_SLOW; else st->adis.spi->max_speed_hz = ADIS16400_SPI_FAST; - return adis_write_reg_8(&st->adis, ADIS16400_SMPL_PRD, t); + return adis_write_reg_8(&st->adis, ADIS16400_SMPL_PRD, val); } static ssize_t adis16400_read_frequency(struct device *dev, -- cgit v1.2.3