linux-kernel - [PATCH v4 3/4] i2c: imx: use readb_relaxed and writeb

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Message-ID: <20241002112020.23913-4-eichest@gmail.com>
Date: Wed,  2 Oct 2024 13:19:41 +0200
From: Stefan Eichenberger <eichest@...il.com>
To: o.rempel@...gutronix.de,
	kernel@...gutronix.de,
	andi.shyti@...nel.org,
	shawnguo@...nel.org,
	s.hauer@...gutronix.de,
	festevam@...il.com,
	Frank.Li@....com
Cc: linux-i2c@...r.kernel.org,
	imx@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	francesco.dolcini@...adex.com,
	Stefan Eichenberger <stefan.eichenberger@...adex.com>
Subject: [PATCH v4 3/4] i2c: imx: use readb_relaxed and writeb_relaxed

From: Stefan Eichenberger <stefan.eichenberger@...adex.com>

Use the relaxed version of readb and writeb to reduce overhead. It is
safe to use the relaxed version because we either do not rely on dma
completion, or we use a dma callback to ensure that the dma transfer is
complete before we continue.

Signed-off-by: Stefan Eichenberger <stefan.eichenberger@...adex.com>
Acked-by: Oleksij Rempel <o.rempel@...gutronix.de>
---
 drivers/i2c/busses/i2c-imx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 8e9cdeff278a8..f70522a83f823 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -313,13 +313,13 @@ static inline int is_vf610_i2c(struct imx_i2c_struct *i2c_imx)
 static inline void imx_i2c_write_reg(unsigned int val,
 		struct imx_i2c_struct *i2c_imx, unsigned int reg)
 {
-	writeb(val, i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
+	writeb_relaxed(val, i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
 }
 
 static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx,
 		unsigned int reg)
 {
-	return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
+	return readb_relaxed(i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
 }
 
 static void i2c_imx_clear_irq(struct imx_i2c_struct *i2c_imx, unsigned int bits)
-- 
2.43.0