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Subject[PATCH v2 2/2] i2c:imx: Add an extra read at the end of an I2C slave read
Date
From: Corey Minyard <minyard@acm.org>

The I2C slave interface expects that the driver will read ahead one
byte. The IMX driver/device doesn't do this, but simulate it so that
read operations get their index set correctly.

Signed-off-by: Corey Minyard <minyard@acm.org>
Tested-by: Andrew Manley <andrew.manley@sealingtech.com>
Reviewed-by: Andrew Manley <andrew.manley@sealingtech.com>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
drivers/i2c/busses/i2c-imx.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 27f969b3dc07..41355fc8bff4 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -771,6 +771,15 @@ static irqreturn_t i2c_imx_slave_handle(struct imx_i2c_struct *i2c_imx,
ctl &= ~I2CR_MTX;
imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
+
+ /*
+ * The i2c slave interface requires one extra dummy
+ * read at the end to keep things in line. See the
+ * I2C slave docs for details.
+ */
+ i2c_imx_slave_event(i2c_imx,
+ I2C_SLAVE_READ_PROCESSED, &value);
+
i2c_imx_slave_finish_op(i2c_imx);
return IRQ_HANDLED;
}
--
2.25.1
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