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[v3,1/8] iio: adc: max1027: Add debugfs register read support

Message ID 20191007132657.4190-2-miquel.raynal@bootlin.com (mailing list archive)
State New, archived
Headers show
Series Introduce max12xx ADC support | expand

Commit Message

Miquel Raynal Oct. 7, 2019, 1:26 p.m. UTC
Until now, only write operations were supported. Force two bytes read
operation when reading, which should fit most of the development
purposes. Of course, extended operations like buffered reads on
multiple channels or even temperature + voltage reads will not be read
entirely. Usually, just starting a new operation will work but in any
case a software reset (done through the debufs interface too) will
return the device in a usable state.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/iio/adc/max1027.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
index 214883458582..6cdfe9ef73fc 100644
--- a/drivers/iio/adc/max1027.c
+++ b/drivers/iio/adc/max1027.c
@@ -309,8 +309,11 @@  static int max1027_debugfs_reg_access(struct iio_dev *indio_dev,
 	struct max1027_state *st = iio_priv(indio_dev);
 	u8 *val = (u8 *)st->buffer;
 
-	if (readval != NULL)
-		return -EINVAL;
+	if (readval) {
+		int ret = spi_read(st->spi, val, 2);
+		*readval = be16_to_cpu(st->buffer[0]);
+		return ret;
+	}
 
 	*val = (u8)writeval;
 	return spi_write(st->spi, val, 1);