linux-kernel - [PATCH v4 15/31] i2c: tegra: Remove bogus barrier()

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Message-Id: <20200905204151.25343-16-digetx@gmail.com>
Date:   Sat,  5 Sep 2020 23:41:35 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     linux-i2c@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 15/31] i2c: tegra: Remove bogus barrier()

Apparently barrier() was intended to reduce possibility of racing
with the interrupt handler, but driver's code evolved significantly
and today's driver enables interrupt only when it waits for completion
notification. Hence barrier() has no good use anymore, let's remove it.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/i2c/busses/i2c-tegra.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 33d37a40fa83..f69587ca163b 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -600,7 +600,6 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 		i2c_dev->msg_buf_remaining = buf_remaining;
 		i2c_dev->msg_buf = buf +
 			words_to_transfer * BYTES_PER_FIFO_WORD;
-		barrier();
 
 		i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
 
@@ -624,7 +623,6 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 		/* Again update before writing to FIFO to make sure isr sees. */
 		i2c_dev->msg_buf_remaining = 0;
 		i2c_dev->msg_buf = NULL;
-		barrier();
 
 		i2c_writel(i2c_dev, val, I2C_TX_FIFO);
 	}
-- 
2.27.0