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add i2c retries 

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

SVN-Revision: 33565
owl
Imre Kaloz 2012-09-27 08:06:13 +00:00
parent 7dd6b04c28
commit 9ace6ace8f
1 changed files with 72 additions and 0 deletions
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72
target/linux/cns3xxx/patches-3.3/440-i2c_retry.patch Normal file
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@ -0,0 +1,72 @@
--- a/drivers/i2c/busses/i2c-cns3xxx.c
+++ b/drivers/i2c/busses/i2c-cns3xxx.c
@@ -2,8 +2,9 @@
* Cavium CNS3xxx I2C Host Controller
*
* Copyright 2010 Cavium Network
- * Copyright 2011 Gateworks Corporation
+ * Copyright 2012 Gateworks Corporation
* Chris Lang <clang@gateworks.com>
+ * Tim Harvey <tharvey@gateworks.com>
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, Version 2, as
@@ -63,13 +64,15 @@
#define STATE_ERROR 2
struct cns3xxx_i2c {
- void __iomem *base;
- wait_queue_head_t wait;
- struct i2c_adapter adap;
- struct i2c_msg *msg;
- int state; /* see STATE_ */
- int rd_wr_len;
- u8 *buf;
+ struct device *dev;
+ void __iomem *base; /* virtual */
+ wait_queue_head_t wait;
+ struct i2c_adapter adap;
+ struct i2c_msg *msg;
+ u8 state; /* see STATE_ */
+ u8 error; /* see TWI_STATUS register */
+ int rd_wr_len;
+ u8 *buf;
};
static u32 cns3xxx_i2c_func(struct i2c_adapter *adap)
@@ -150,14 +153,18 @@ cns3xxx_i2c_xfer_msg(struct i2c_adapter
// Start the Transfer
i2c->state = 0; // Clear out the State
+ i2c->error = 0;
I2C_CONTROLLER_REG |= (1 << 6);
if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
(i2c->state == STATE_DONE), TWI_TIMEOUT)) {
if (i2c->state == STATE_ERROR) {
- return -EIO;
+ dev_dbg(i2c->dev, "controller error: 0x%2x", i2c->error);
+ return -EAGAIN; // try again
}
} else {
+ dev_err(i2c->dev, "controller timed out "
+ "waiting for start condition to finish\n");
return -ETIMEDOUT;
}
}
@@ -238,6 +245,7 @@ static irqreturn_t cns3xxx_i2c_isr(int i
if (stat & I2C_BUS_ERROR_FLAG) {
i2c->state = STATE_ERROR;
+ i2c->error = (I2C_INTERRUPT_STATUS_REG & 0xff00)>>8;
} else {
if (i2c->msg->flags & I2C_M_RD) {
for (i = 0; i <= i2c->rd_wr_len; i++)
@@ -280,6 +288,7 @@ static int __devinit cns3xxx_i2c_probe(s
goto request_mem_failed;
}
+ i2c->dev = &pdev->dev;
i2c->base = ioremap(res->start, res->end - res->start + 1);
if (!i2c->base) {
dev_err(&pdev->dev, "Unable to map registers\n");