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From: Akhil R <akhilrajeev@nvidia.com>
To: <andriy.shevchenko@linux.intel.com>, <andi.shyti@kernel.org>,
	<digetx@gmail.com>, <jonathanh@nvidia.com>,
	<linux-i2c@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-tegra@vger.kernel.org>, <p.zabel@pengutronix.de>,
	<thierry.reding@gmail.com>
Cc: <akhilrajeev@nvidia.com>, <conor+dt@kernel.org>,
	<devicetree@vger.kernel.org>, <krzk+dt@kernel.org>,
	<ldewangan@nvidia.com>, <robh@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Thierry Reding <treding@nvidia.com>
Subject: [PATCH v5 3/3] i2c: tegra: Remove dma_sync_*() calls
Date: Wed, 2 Jul 2025 19:04:49 +0530	[thread overview]
Message-ID: <20250702133450.64257-3-akhilrajeev@nvidia.com> (raw)
In-Reply-To: <20250702133450.64257-1-akhilrajeev@nvidia.com>

Calling dma_sync_*() on a buffer from dma_alloc_coherent() is pointless.
The driver should not be doing its own bounce-buffering if the buffer is
allocated through dma_alloc_coherent()

Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
---
v1->v5: No change.

 drivers/i2c/busses/i2c-tegra.c | 20 +-------------------
 1 file changed, 1 insertion(+), 19 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index b24882b76c6d..4f1925f74655 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1303,17 +1303,9 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 
 	if (i2c_dev->dma_mode) {
 		if (i2c_dev->msg_read) {
-			dma_sync_single_for_device(i2c_dev->dma_dev,
-						   i2c_dev->dma_phys,
-						   xfer_size, DMA_FROM_DEVICE);
-
 			err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
 			if (err)
 				return err;
-		} else {
-			dma_sync_single_for_cpu(i2c_dev->dma_dev,
-						i2c_dev->dma_phys,
-						xfer_size, DMA_TO_DEVICE);
 		}
 	}
 
@@ -1323,11 +1315,6 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 		if (i2c_dev->dma_mode) {
 			memcpy(i2c_dev->dma_buf + I2C_PACKET_HEADER_SIZE,
 			       msg->buf, i2c_dev->msg_len);
-
-			dma_sync_single_for_device(i2c_dev->dma_dev,
-						   i2c_dev->dma_phys,
-						   xfer_size, DMA_TO_DEVICE);
-
 			err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
 			if (err)
 				return err;
@@ -1368,13 +1355,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 			return -ETIMEDOUT;
 		}
 
-		if (i2c_dev->msg_read && i2c_dev->msg_err == I2C_ERR_NONE) {
-			dma_sync_single_for_cpu(i2c_dev->dma_dev,
-						i2c_dev->dma_phys,
-						xfer_size, DMA_FROM_DEVICE);
-
+		if (i2c_dev->msg_read && i2c_dev->msg_err == I2C_ERR_NONE)
 			memcpy(i2c_dev->msg_buf, i2c_dev->dma_buf, i2c_dev->msg_len);
-		}
 	}
 
 	time_left = tegra_i2c_wait_completion(i2c_dev, &i2c_dev->msg_complete,
-- 
2.49.0


  parent reply	other threads:[~2025-07-02 13:36 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-02 13:34 [PATCH v5 1/3] i2c: tegra: Fix reset error handling with ACPI Akhil R
2025-07-02 13:34 ` [PATCH v5 2/3] i2c: tegra: make reset an optional property Akhil R
2025-07-02 15:11   ` Andy Shevchenko
2025-07-03 16:02   ` kernel test robot
2025-07-02 13:34 ` Akhil R [this message]
2025-07-02 15:24   ` [PATCH v5 3/3] i2c: tegra: Remove dma_sync_*() calls Andy Shevchenko
2025-07-02 15:04 ` [PATCH v5 1/3] i2c: tegra: Fix reset error handling with ACPI Andy Shevchenko
2025-07-02 15:13   ` Andy Shevchenko
2025-07-02 17:10     ` Akhil R
2025-07-03  8:31       ` Philipp Zabel
2025-07-03 14:11         ` Andy Shevchenko
2025-07-04  6:47           ` Akhil R

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