From fce7c3eac7d4ca77ada5bf8332f867219fbb5068 Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <lars@metafoo.de>
Date: Mon, 5 Nov 2012 09:56:00 +0000
Subject: [PATCH] staging:iio:ad7887: Allow to use internal ref in two channel
mode
While it is not recommended to use the internal reference in two channel mode in
order to obtain optimal performance it is still possible to use it.
While we are at it also get rid of the duplicate tx_cmd_buf entries. There are
only two unique entries. One for channel 1 and one for channel 2.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
drivers/staging/iio/adc/ad7887.c | 28 +++++++++++++---------------
1 file changed, 13 insertions(+), 15 deletions(-)
diff --git a/drivers/staging/iio/adc/ad7887.c b/drivers/staging/iio/adc/ad7887.c
index 88ffc4620fc8..3ac0c305e123 100644
--- a/drivers/staging/iio/adc/ad7887.c
+++ b/drivers/staging/iio/adc/ad7887.c
@@ -59,7 +59,7 @@ struct ad7887_state {
struct spi_transfer xfer[4];
struct spi_message msg[3];
struct spi_message *ring_msg;
- unsigned char tx_cmd_buf[8];
+ unsigned char tx_cmd_buf[4];
/*
* DMA (thus cache coherency maintenance) requires the
@@ -238,6 +238,7 @@ static int __devinit ad7887_probe(struct spi_device *spi)
struct ad7887_platform_data *pdata = spi->dev.platform_data;
struct ad7887_state *st;
struct iio_dev *indio_dev = iio_device_alloc(sizeof(*st));
+ uint8_t mode;
int ret;
if (indio_dev == NULL)
@@ -271,9 +272,13 @@ static int __devinit ad7887_probe(struct spi_device *spi)
/* Setup default message */
- st->tx_cmd_buf[0] = AD7887_CH_AIN0 | AD7887_PM_MODE4 |
- ((pdata && pdata->use_onchip_ref) ?
- 0 : AD7887_REF_DIS);
+ mode = AD7887_PM_MODE4;
+ if (!pdata || !pdata->use_onchip_ref)
+ mode |= AD7887_REF_DIS;
+ if (pdata && pdata->en_dual)
+ mode |= AD7887_DUAL;
+
+ st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode;
st->xfer[0].rx_buf = &st->data[0];
st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
@@ -283,29 +288,22 @@ static int __devinit ad7887_probe(struct spi_device *spi)
spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
if (pdata && pdata->en_dual) {
- st->tx_cmd_buf[0] |= AD7887_DUAL | AD7887_REF_DIS;
-
- st->tx_cmd_buf[2] = AD7887_CH_AIN1 | AD7887_DUAL |
- AD7887_REF_DIS | AD7887_PM_MODE4;
- st->tx_cmd_buf[4] = AD7887_CH_AIN0 | AD7887_DUAL |
- AD7887_REF_DIS | AD7887_PM_MODE4;
- st->tx_cmd_buf[6] = AD7887_CH_AIN1 | AD7887_DUAL |
- AD7887_REF_DIS | AD7887_PM_MODE4;
+ st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode;
st->xfer[1].rx_buf = &st->data[0];
st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
st->xfer[1].len = 2;
st->xfer[2].rx_buf = &st->data[2];
- st->xfer[2].tx_buf = &st->tx_cmd_buf[4];
+ st->xfer[2].tx_buf = &st->tx_cmd_buf[0];
st->xfer[2].len = 2;
spi_message_init(&st->msg[AD7887_CH0_CH1]);
spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);
- st->xfer[3].rx_buf = &st->data[0];
- st->xfer[3].tx_buf = &st->tx_cmd_buf[6];
+ st->xfer[3].rx_buf = &st->data[2];
+ st->xfer[3].tx_buf = &st->tx_cmd_buf[2];
st->xfer[3].len = 2;
spi_message_init(&st->msg[AD7887_CH1]);