Merge branch 'for-31-rc5/i2c-fixes' of git://git.fluff.org/bjdooks/linux

* 'for-31-rc5/i2c-fixes' of git://git.fluff.org/bjdooks/linux:
  i2c-tegra: fix possible race condition after tx
  i2c-tegra: add I2C_FUNC_SMBUS_EMUL
  i2c-tegra: Add of_match_table
  i2c-pxa2xx: return proper error code in ce4100_i2c_probe error paths

diff --git a/drivers/i2c/busses/i2c-pxa-pci.c b/drivers/i2c/busses/i2c-pxa-pci.c
index 6659d26..b73da6c 100644 (file)
--- a/drivers/i2c/busses/i2c-pxa-pci.c
+++ b/drivers/i2c/busses/i2c-pxa-pci.c
@@ -109,12 +109,15 @@ static int __devinit ce4100_i2c_probe(struct pci_dev *dev,
                return -EINVAL;
        }
        sds = kzalloc(sizeof(*sds), GFP_KERNEL);
-       if (!sds)
+       if (!sds) {
+               ret = -ENOMEM;
                goto err_mem;
+       }
 
        for (i = 0; i < ARRAY_SIZE(sds->pdev); i++) {
                sds->pdev[i] = add_i2c_device(dev, i);
                if (IS_ERR(sds->pdev[i])) {
+                       ret = PTR_ERR(sds->pdev[i]);
                        while (--i >= 0)
                                platform_device_unregister(sds->pdev[i]);
                        goto err_dev_add;

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 2440b74..3c94c4a 100644 (file)
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -270,14 +270,30 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 
        /* Rounds down to not include partial word at the end of buf */
        words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
-       if (words_to_transfer > tx_fifo_avail)
-               words_to_transfer = tx_fifo_avail;
 
-       i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
-
-       buf += words_to_transfer * BYTES_PER_FIFO_WORD;
-       buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
-       tx_fifo_avail -= words_to_transfer;
+       /* It's very common to have < 4 bytes, so optimize that case. */
+       if (words_to_transfer) {
+               if (words_to_transfer > tx_fifo_avail)
+                       words_to_transfer = tx_fifo_avail;
+
+               /*
+                * Update state before writing to FIFO.  If this casues us
+                * to finish writing all bytes (AKA buf_remaining goes to 0) we
+                * have a potential for an interrupt (PACKET_XFER_COMPLETE is
+                * not maskable).  We need to make sure that the isr sees
+                * buf_remaining as 0 and doesn't call us back re-entrantly.
+                */
+               buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
+               tx_fifo_avail -= words_to_transfer;
+               i2c_dev->msg_buf_remaining = buf_remaining;
+               i2c_dev->msg_buf = buf +
+                       words_to_transfer * BYTES_PER_FIFO_WORD;
+               barrier();
+
+               i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
+
+               buf += words_to_transfer * BYTES_PER_FIFO_WORD;
+       }
 
        /*
         * If there is a partial word at the end of buf, handle it manually to
@@ -287,14 +303,15 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
        if (tx_fifo_avail > 0 && buf_remaining > 0) {
                BUG_ON(buf_remaining > 3);
                memcpy(&val, buf, buf_remaining);
+
+               /* Again update before writing to FIFO to make sure isr sees. */
+               i2c_dev->msg_buf_remaining = 0;
+               i2c_dev->msg_buf = NULL;
+               barrier();
+
                i2c_writel(i2c_dev, val, I2C_TX_FIFO);
-               buf_remaining = 0;
-               tx_fifo_avail--;
        }
 
-       BUG_ON(tx_fifo_avail > 0 && buf_remaining > 0);
-       i2c_dev->msg_buf_remaining = buf_remaining;
-       i2c_dev->msg_buf = buf;
        return 0;
 }
 
@@ -411,9 +428,10 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
                        tegra_i2c_mask_irq(i2c_dev, I2C_INT_TX_FIFO_DATA_REQ);
        }
 
-       if ((status & I2C_INT_PACKET_XFER_COMPLETE) &&
-                       !i2c_dev->msg_buf_remaining)
+       if (status & I2C_INT_PACKET_XFER_COMPLETE) {
+               BUG_ON(i2c_dev->msg_buf_remaining);
                complete(&i2c_dev->msg_complete);
+       }
 
        i2c_writel(i2c_dev, status, I2C_INT_STATUS);
        if (i2c_dev->is_dvc)
@@ -531,7 +549,7 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 
 static u32 tegra_i2c_func(struct i2c_adapter *adap)
 {
-       return I2C_FUNC_I2C;
+       return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }
 
 static const struct i2c_algorithm tegra_i2c_algo = {
@@ -719,6 +737,17 @@ static int tegra_i2c_resume(struct platform_device *pdev)
 }
 #endif
 
+#if defined(CONFIG_OF)
+/* Match table for of_platform binding */
+static const struct of_device_id tegra_i2c_of_match[] __devinitconst = {
+       { .compatible = "nvidia,tegra20-i2c", },
+       {},
+};
+MODULE_DEVICE_TABLE(of, tegra_i2c_of_match);
+#else
+#define tegra_i2c_of_match NULL
+#endif
+
 static struct platform_driver tegra_i2c_driver = {
        .probe   = tegra_i2c_probe,
        .remove  = tegra_i2c_remove,
@@ -729,6 +758,7 @@ static struct platform_driver tegra_i2c_driver = {
        .driver  = {
                .name  = "tegra-i2c",
                .owner = THIS_MODULE,
+               .of_match_table = tegra_i2c_of_match,
        },
 };