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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        =?UTF-8?q?Nuno=20S=C3=A1?= <nuno.sa@analog.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.18 0623/1095] iio: adc: ti-tlc4541: Fix alignment for DMA safety
Date:   Mon, 15 Aug 2022 20:00:22 +0200
Message-Id: <20220815180455.236407383@linuxfoundation.org>
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From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

[ Upstream commit 62fa19bf484bfeb52c56b7c6d6a6b1222c597f9c ]

____cacheline_aligned is an insufficient guarantee for non-coherent DMA
on platforms with 128 byte cachelines above L1.  Switch to the updated
IIO_DMA_MINALIGN definition.

Update the comment to include 'may'.

Fixes: ac2bec9d587c ("iio: adc: tlc4541: add support for TI tlc4541 adc")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-40-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iio/adc/ti-tlc4541.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ti-tlc4541.c b/drivers/iio/adc/ti-tlc4541.c
index 2406eda9dfc6..30f629a553a1 100644
--- a/drivers/iio/adc/ti-tlc4541.c
+++ b/drivers/iio/adc/ti-tlc4541.c
@@ -37,12 +37,12 @@ struct tlc4541_state {
 	struct spi_message              scan_single_msg;
 
 	/*
-	 * DMA (thus cache coherency maintenance) requires the
+	 * DMA (thus cache coherency maintenance) may require the
 	 * transfer buffers to live in their own cache lines.
 	 * 2 bytes data + 6 bytes padding + 8 bytes timestamp when
 	 * call iio_push_to_buffers_with_timestamp.
 	 */
-	__be16                          rx_buf[8] ____cacheline_aligned;
+	__be16                          rx_buf[8] __aligned(IIO_DMA_MINALIGN);
 };
 
 struct tlc4541_chip_info {
-- 
2.35.1