linux-kernel - [PATCH] i2c: exynos5: Preserve high speed master code

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Date:   Mon, 15 Feb 2021 20:03:21 +0100
From:   Mårten Lindahl <marten.lindahl@...s.com>
To:     Krzysztof Kozlowski <krzk@...nel.org>
CC:     <kernel@...s.com>,
        Mårten Lindahl <martenli@...s.com>,
        <linux-i2c@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-samsung-soc@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] i2c: exynos5: Preserve high speed master code

From: Mårten Lindahl <martenli@...s.com>

When the controller starts to send a message with the MASTER_ID field
set (high speed), the whole I2C_ADDR register is overwritten including
MASTER_ID as the SLV_ADDR_MAS field is set.

This patch preserves already written fields in I2C_ADDR when writing
SLV_ADDR_MAS.

Signed-off-by: Mårten Lindahl <martenli@...s.com>
---
 drivers/i2c/busses/i2c-exynos5.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
index 20a9881a0d6c..f2d04c241299 100644
--- a/drivers/i2c/busses/i2c-exynos5.c
+++ b/drivers/i2c/busses/i2c-exynos5.c
@@ -606,6 +606,7 @@ static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop)
 	u32 i2c_ctl;
 	u32 int_en = 0;
 	u32 i2c_auto_conf = 0;
+	u32 i2c_addr = 0;
 	u32 fifo_ctl;
 	unsigned long flags;
 	unsigned short trig_lvl;
@@ -640,7 +641,12 @@ static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop)
 		int_en |= HSI2C_INT_TX_ALMOSTEMPTY_EN;
 	}
 
-	writel(HSI2C_SLV_ADDR_MAS(i2c->msg->addr), i2c->regs + HSI2C_ADDR);
+	i2c_addr = HSI2C_SLV_ADDR_MAS(i2c->msg->addr);
+
+	if (i2c->op_clock >= I2C_MAX_FAST_MODE_PLUS_FREQ)
+		i2c_addr |= readl(i2c->regs + HSI2C_ADDR);
+
+	writel(i2c_addr, i2c->regs + HSI2C_ADDR);
 
 	writel(fifo_ctl, i2c->regs + HSI2C_FIFO_CTL);
 	writel(i2c_ctl, i2c->regs + HSI2C_CTL);
-- 
2.11.0