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i2c: imx: retry on NAK

PATCH In review Luka Perkov 2 participants 2 messages Sep 10, 2013 – Feb 18, 2014 1 message not in the archive

Subsystems (3)
Arm i.MX and Layerscape I2C subsystem host drivers Freescale i.MX I2C driver
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Luka Perkov

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PATCH 1/1 i2c: imx: retry on NAK

From: Tim Harvey <tharvey-UMMOYl/[email protected]>

In case of busy i2c try again to get ACK.

Signed-off-by Tim Harvey <tharvey-UMMOYl/[email protected]>
Tested-by Luka Perkov <[email protected]>
---
 drivers/i2c/busses/i2c-imx.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
drivers/i2c/busses/i2c-imx.c +3 -1
index ccf4665..c64afe6 100644
@@ -62,6 +62,7 @@
 
 /* Default value */
 #define IMX_I2C_BIT_RATE	100000	/* 100kHz */
+#define IMX_I2C_MAX_RETRIES	3	/* number of retries to attempt */
 
 /* IMX I2C registers:
  * the I2C register offset is different between SoCs,

@@ -298,7 +299,7 @@ static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx)
 {
 	if (imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR) & I2SR_RXAK) {
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
-		return -EIO;  /* No ACK */
+		return -EAGAIN; /* try again */
 	}
 
 	dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__);

@@ -633,6 +634,7 @@ static int __init i2c_imx_probe(struct platform_device *pdev)
 	i2c_imx->adapter.dev.parent	= &pdev->dev;
 	i2c_imx->adapter.nr 		= pdev->id;
 	i2c_imx->adapter.dev.of_node	= pdev->dev.of_node;
+	i2c_imx->adapter.retries	= IMX_I2C_MAX_RETRIES;
 	i2c_imx->base			= base;
 
 	/* Get I2C clock */
Signature · 1 line
1.8.4

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