From 5748150eabdacd3f870c311b63d32f5e312bf624 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Jos=C3=A9=20Miguel=20Gon=C3=A7alves?= Date: Fri, 5 Mar 2010 13:43:58 -0800 Subject: [PATCH] drivers/hwmon/adcxx.c: fix for single-channel ADCs While testing an ADC121S021 in an embedded board with a S3C2142 SoC (ARM core), I have found that the 'adcxx' driver does not handle correctly single channel ADCs from this chip family. For single channel chips you must only issue one read transfer for correct measurement. Signed-off-by: Jose Miguel Goncalves Cc: Marc Pignat Cc: Anton Vorontsov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/hwmon/adcxx.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/hwmon/adcxx.c b/drivers/hwmon/adcxx.c index 5e9e095f1136..74d9c5195e44 100644 --- a/drivers/hwmon/adcxx.c +++ b/drivers/hwmon/adcxx.c @@ -62,18 +62,23 @@ static ssize_t adcxx_read(struct device *dev, struct spi_device *spi = to_spi_device(dev); struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); struct adcxx *adc = dev_get_drvdata(&spi->dev); - u8 tx_buf[2] = { attr->index << 3 }; /* other bits are don't care */ + u8 tx_buf[2]; u8 rx_buf[2]; int status; - int value; + u32 value; if (mutex_lock_interruptible(&adc->lock)) return -ERESTARTSYS; - status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf), - rx_buf, sizeof(rx_buf)); + if (adc->channels == 1) { + status = spi_read(spi, rx_buf, sizeof(rx_buf)); + } else { + tx_buf[0] = attr->index << 3; /* other bits are don't care */ + status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf), + rx_buf, sizeof(rx_buf)); + } if (status < 0) { - dev_warn(dev, "spi_write_then_read failed with status %d\n", + dev_warn(dev, "SPI synch. transfer failed with status %d\n", status); goto out; } -- 2.20.1