[cns3xxx]: add i2c retries

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@33565 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/target/linux/cns3xxx/patches-3.3/440-i2c_retry.patch b/target/linux/cns3xxx/patches-3.3/440-i2c_retry.patch
new file mode 100644 (file)
index 0000000..707de82
--- /dev/null
+++ b/target/linux/cns3xxx/patches-3.3/440-i2c_retry.patch
@@ -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");