linux-kernel - [PATCH 4.9 23/87] iio: magnetometer: mag3110: claim direct mode during raw writes

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Date:   Mon, 13 Nov 2017 13:55:40 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Alison Schofield <amsfield22@...il.com>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        Jonathan Cameron <jic23@...nel.org>,
        Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.9 23/87] iio: magnetometer: mag3110: claim direct mode during raw writes

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alison Schofield <amsfield22@...il.com>


[ Upstream commit 80dea21f95a4672cce545f48dc2ca500b69a2584 ]

Driver was checking for direct mode but not locking it.  Use
claim/release helper functions to guarantee the device stays
in direct mode during raw writes.

Signed-off-by: Alison Schofield <amsfield22@...il.com>
Acked-by: Peter Meerwald-Stadler <pmeerw@...erw.net>
Signed-off-by: Jonathan Cameron <jic23@...nel.org>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/iio/magnetometer/mag3110.c |   30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

--- a/drivers/iio/magnetometer/mag3110.c
+++ b/drivers/iio/magnetometer/mag3110.c
@@ -222,29 +222,39 @@ static int mag3110_write_raw(struct iio_
 			     int val, int val2, long mask)
 {
 	struct mag3110_data *data = iio_priv(indio_dev);
-	int rate;
+	int rate, ret;
 
-	if (iio_buffer_enabled(indio_dev))
-		return -EBUSY;
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return ret;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		rate = mag3110_get_samp_freq_index(data, val, val2);
-		if (rate < 0)
-			return -EINVAL;
+		if (rate < 0) {
+			ret = -EINVAL;
+			break;
+		}
 
 		data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;
 		data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
-		return i2c_smbus_write_byte_data(data->client,
+		ret = i2c_smbus_write_byte_data(data->client,
 			MAG3110_CTRL_REG1, data->ctrl_reg1);
+		break;
 	case IIO_CHAN_INFO_CALIBBIAS:
-		if (val < -10000 || val > 10000)
-			return -EINVAL;
-		return i2c_smbus_write_word_swapped(data->client,
+		if (val < -10000 || val > 10000) {
+			ret = -EINVAL;
+			break;
+		}
+		ret = i2c_smbus_write_word_swapped(data->client,
 			MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
+		break;
 	default:
-		return -EINVAL;
+		ret = -EINVAL;
+		break;
 	}
+	iio_device_release_direct_mode(indio_dev);
+	return ret;
 }
 
 static irqreturn_t mag3110_trigger_handler(int irq, void *p)