From mboxrd@z Thu Jan 1 00:00:00 1970 From: Miquel Raynal Subject: [PATCH v3 1/8] iio: adc: max1027: Add debugfs register read support Date: Mon, 7 Oct 2019 15:26:50 +0200 Message-ID: <20191007132657.4190-2-miquel.raynal@bootlin.com> References: <20191007132657.4190-1-miquel.raynal@bootlin.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20191007132657.4190-1-miquel.raynal@bootlin.com> Sender: linux-kernel-owner@vger.kernel.org To: Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Rob Herring , Mark Rutland Cc: devicetree@vger.kernel.org, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Petazzoni , Miquel Raynal List-Id: devicetree@vger.kernel.org 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 --- drivers/iio/adc/max1027.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) 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); -- 2.20.1