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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>,
	<ldewangan@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>,
	<robh@kernel.org>, "Robin Murphy" <robin.murphy@arm.com>,
	Thierry Reding <treding@nvidia.com>
Subject: [PATCH v6 3/3] i2c: tegra: Remove dma_sync_*() calls
Date: Thu, 10 Jul 2025 18:42:06 +0530	[thread overview]
Message-ID: <20250710131206.2316-4-akhilrajeev@nvidia.com> (raw)
In-Reply-To: <20250710131206.2316-1-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>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 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 e291b8586214..04a9610c0736 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1293,17 +1293,9 @@ 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);
 		}
 	}
 
@@ -1313,11 +1305,6 @@ 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;
@@ -1358,13 +1345,8 @@ 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,
-- 
2.50.1


  parent reply	other threads:[~2025-07-10 13:13 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-10 13:12 [PATCH v6 0/3] i2c: tegra: Improve reset and DMA operations Akhil R
2025-07-10 13:12 ` [PATCH v6 1/3] i2c: tegra: Fix reset error handling with ACPI Akhil R
2025-07-10 13:50   ` Andy Shevchenko
2025-07-11 15:59     ` Andi Shyti
2025-07-10 13:12 ` [PATCH v6 2/3] i2c: tegra: Use internal reset when reset property is not available Akhil R
2025-07-10 13:53   ` Andy Shevchenko
2025-07-11 16:00     ` Andi Shyti
2025-07-14  5:22       ` Akhil R
2025-07-14  8:19         ` Andy Shevchenko
2025-07-10 13:12 ` Akhil R [this message]
2025-07-14 20:19 ` [PATCH v6 0/3] i2c: tegra: Improve reset and DMA operations Andi Shyti

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