On Mon, 2011-08-15 at 18:32 -0700, Doug Anderson wrote: > This change doesn't fix any known problems but turns > on the overflow detection feature of the i2c controller > in the hopes of flushing out any current (or future) > bugs in the i2c driver. > > Inspired by a change on nvidia's git server: > http://nv-tegra.nvidia.com/gitweb/?p=linux-2.6.git;a=commit;h=266d1b7397284505e55d06254b497cb32be07b69 > > Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx> > --- > This takes Felipe Balbi's suggestion of making the overflow > error non-fatal. > > drivers/i2c/busses/i2c-tegra.c | 17 ++++++++++++++--- > 1 files changed, 14 insertions(+), 3 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c > index 2440b74..34634b7 100644 > --- a/drivers/i2c/busses/i2c-tegra.c > +++ b/drivers/i2c/busses/i2c-tegra.c > @@ -83,6 +83,7 @@ > #define I2C_ERR_NO_ACK 0x01 > #define I2C_ERR_ARBITRATION_LOST 0x02 > #define I2C_ERR_UNKNOWN_INTERRUPT 0x04 > +#define I2C_ERR_FIFO_OVERFLOW 0x08 > > #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28 > #define PACKET_HEADER0_PACKET_ID_SHIFT 16 > @@ -367,7 +368,8 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) > static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) > { > u32 status; > - const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; > + const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | > + I2C_INT_TX_FIFO_OVERFLOW; > struct tegra_i2c_dev *i2c_dev = dev_id; > > status = i2c_readl(i2c_dev, I2C_INT_STATUS); > @@ -389,6 +391,14 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) > } > > if (unlikely(status & status_err)) { > + /* > + * Overflow should be impossible unless we've got a > + * bug in the driver, but check anyway. > + */ > + if (status & I2C_INT_TX_FIFO_OVERFLOW) { > + WARN_ON(1); > + i2c_dev->msg_err |= I2C_ERR_FIFO_OVERFLOW; > + } > if (status & I2C_INT_NO_ACK) > i2c_dev->msg_err |= I2C_ERR_NO_ACK; > if (status & I2C_INT_ARBITRATION_LOST) > @@ -423,7 +433,7 @@ err: > /* An error occurred, mask all interrupts */ > tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | > I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ | > - I2C_INT_RX_FIFO_DATA_REQ); > + I2C_INT_RX_FIFO_DATA_REQ | I2C_INT_TX_FIFO_OVERFLOW); > i2c_writel(i2c_dev, status, I2C_INT_STATUS); > if (i2c_dev->is_dvc) > dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); > @@ -473,7 +483,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, > if (!(msg->flags & I2C_M_RD)) > tegra_i2c_fill_tx_fifo(i2c_dev); > > - int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; > + int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | > + I2C_INT_TX_FIFO_OVERFLOW; > if (msg->flags & I2C_M_RD) > int_mask |= I2C_INT_RX_FIFO_DATA_REQ; > else if (i2c_dev->msg_buf_remaining) Seems good to me. Acked-by: Rhyland Klein <rklein@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
