From: Wei Ni <[email protected]> Sometimes unexpected status like I2C busy status, Tx FIFO interrupted and wait on Rx data etc is seen. Add a code to detect such conditions and return -EAGAIN from driver. This will cause the i2c-core to retry the transmission as per the retry count and time-out specified by the platform data of the adapter. And for no_ack status, also retrun -EAGAIN to retry.
Signed-off-by: Wei Ni <[email protected]> --- drivers/i2c/busses/i2c-tegra.c | 29 ++++++++++++++++++++++++++--- include/linux/i2c-tegra.h | 2 ++ 2 files changed, 28 insertions(+), 3 deletions(-) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index b4ab39b..4f5f7f2 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -31,12 +31,15 @@ #include <mach/clk.h> -#define TEGRA_I2C_TIMEOUT (msecs_to_jiffies(1000)) -#define BYTES_PER_FIFO_WORD 4 +#define TEGRA_I2C_TIMEOUT (msecs_to_jiffies(1000)) +#define TEGRA_I2C_RETRIES 3 +#define BYTES_PER_FIFO_WORD 4 #define I2C_CNFG 0x000 #define I2C_CNFG_PACKET_MODE_EN (1<<10) #define I2C_CNFG_NEW_MASTER_FSM (1<<11) +#define I2C_STATUS 0x01C +#define I2C_STATUS_BUSY (1<<8) #define I2C_SL_CNFG 0x020 #define I2C_SL_CNFG_NEWSL (1<<2) #define I2C_SL_ADDR1 0x02c @@ -77,6 +80,7 @@ #define I2C_ERR_NONE 0x00 #define I2C_ERR_NO_ACK 0x01 #define I2C_ERR_ARBITRATION_LOST 0x02 +#define I2C_ERR_UNEXPECTED_STATUS 0x08 #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28 #define PACKET_HEADER0_PACKET_ID_SHIFT 16 @@ -363,6 +367,15 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) goto err; } + if (unlikely((i2c_readl(i2c_dev, I2C_STATUS) & I2C_STATUS_BUSY) + && (status == I2C_INT_TX_FIFO_DATA_REQ) + && i2c_dev->msg_read + && i2c_dev->msg_buf_remaining)) { + i2c_dev->msg_err |= I2C_ERR_UNEXPECTED_STATUS; + complete(&i2c_dev->msg_complete); + goto err; + } + if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) { if (i2c_dev->msg_buf_remaining) tegra_i2c_empty_rx_fifo(i2c_dev); @@ -466,9 +479,12 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, if (i2c_dev->msg_err == I2C_ERR_NO_ACK) { if (msg->flags & I2C_M_IGNORE_NAK) return 0; - return -EREMOTEIO; + return -EAGAIN; } + if (i2c_dev->msg_err & I2C_ERR_UNEXPECTED_STATUS) + return -EAGAIN; + return -EIO; } @@ -598,6 +614,13 @@ static int tegra_i2c_probe(struct platform_device *pdev) i2c_dev->adapter.algo = &tegra_i2c_algo; i2c_dev->adapter.dev.parent = &pdev->dev; i2c_dev->adapter.nr = pdev->id; + if (pdata->retries) + i2c_dev->adapter.retries = pdata->retries; + else + i2c_dev->adapter.retries = TEGRA_I2C_RETRIES; + + if (pdata->timeout) + i2c_dev->adapter.timeout = pdata->timeout; ret = i2c_add_numbered_adapter(&i2c_dev->adapter); if (ret) { diff --git a/include/linux/i2c-tegra.h b/include/linux/i2c-tegra.h index 9c85da4..8ee5b37 100644 --- a/include/linux/i2c-tegra.h +++ b/include/linux/i2c-tegra.h @@ -20,6 +20,8 @@ struct tegra_i2c_platform_data { unsigned long bus_clk_rate; + int retries; + int timeout; /* in jiffies */ }; #endif /* _LINUX_I2C_TEGRA_H */ -- 1.7.0 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
