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From: Cosmin Tanislav <demonsingur@gmail.com>
To: unlisted-recipients:; (no To-header on input)
Cc: "Lars-Peter Clausen" <lars@metafoo.de>,
	"Michael Hennerich" <Michael.Hennerich@analog.com>,
	"Nuno Sá" <nuno.sa@analog.com>,
	"Jonathan Cameron" <jic23@kernel.org>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
	linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	"Cosmin Tanislav" <cosmin.tanislav@analog.com>
Subject: [PATCH v3 1/4] iio: temperature: ltc2983: make bulk write buffer DMA-safe
Date: Tue, 25 Oct 2022 11:18:39 +0300	[thread overview]
Message-ID: <20221025081842.1896748-2-demonsingur@gmail.com> (raw)
In-Reply-To: <20221025081842.1896748-1-demonsingur@gmail.com>

From: Cosmin Tanislav <cosmin.tanislav@analog.com>

regmap_bulk_write() does not guarantee implicit DMA-safety,
even though the current implementation duplicates the given
buffer. Do not rely on it.

Fixes: f110f3188e56 ("iio: temperature: Add support for LTC2983")
Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/iio/temperature/ltc2983.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
index b652d2b39bcf..ca1bb5f48988 100644
--- a/drivers/iio/temperature/ltc2983.c
+++ b/drivers/iio/temperature/ltc2983.c
@@ -209,6 +209,7 @@ struct ltc2983_data {
 	 * Holds the converted temperature
 	 */
 	__be32 temp __aligned(IIO_DMA_MINALIGN);
+	__be32 chan_val;
 };
 
 struct ltc2983_sensor {
@@ -313,19 +314,18 @@ static int __ltc2983_fault_handler(const struct ltc2983_data *st,
 	return 0;
 }
 
-static int __ltc2983_chan_assign_common(const struct ltc2983_data *st,
+static int __ltc2983_chan_assign_common(struct ltc2983_data *st,
 					const struct ltc2983_sensor *sensor,
 					u32 chan_val)
 {
 	u32 reg = LTC2983_CHAN_START_ADDR(sensor->chan);
-	__be32 __chan_val;
 
 	chan_val |= LTC2983_CHAN_TYPE(sensor->type);
 	dev_dbg(&st->spi->dev, "Assign reg:0x%04X, val:0x%08X\n", reg,
 		chan_val);
-	__chan_val = cpu_to_be32(chan_val);
-	return regmap_bulk_write(st->regmap, reg, &__chan_val,
-				 sizeof(__chan_val));
+	st->chan_val = cpu_to_be32(chan_val);
+	return regmap_bulk_write(st->regmap, reg, &st->chan_val,
+				 sizeof(st->chan_val));
 }
 
 static int __ltc2983_chan_custom_sensor_assign(struct ltc2983_data *st,
-- 
2.38.1


  reply	other threads:[~2022-10-25  8:19 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-25  8:18 [PATCH v3 0/4] Support more parts in LTC2983 Cosmin Tanislav
2022-10-25  8:18 ` Cosmin Tanislav [this message]
2022-10-25  8:18 ` [PATCH v3 2/4] dt-bindings: iio: temperature: ltc2983: refine Cosmin Tanislav
2022-10-26 20:03   ` Rob Herring
2022-10-27  7:49     ` Cosmin Tanislav
2022-10-25  8:18 ` [PATCH v3 3/4] dt-bindings: iio: temperature: ltc2983: support more parts Cosmin Tanislav
2022-10-26 20:05   ` Rob Herring
2022-10-25  8:18 ` [PATCH v3 4/4] " Cosmin Tanislav

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