diff options
| -rw-r--r-- | drivers/i2c/busses/i2c-davinci.c | 62 |
1 files changed, 52 insertions, 10 deletions
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c index c56f8fe4efe..16085729695 100644 --- a/drivers/i2c/busses/i2c-davinci.c +++ b/drivers/i2c/busses/i2c-davinci.c @@ -85,6 +85,7 @@ #define DAVINCI_I2C_MDR_MST (1 << 10) #define DAVINCI_I2C_MDR_TRX (1 << 9) #define DAVINCI_I2C_MDR_XA (1 << 8) +#define DAVINCI_I2C_MDR_RM (1 << 7) #define DAVINCI_I2C_MDR_IRS (1 << 5) #define DAVINCI_I2C_IMR_AAS (1 << 6) @@ -112,6 +113,7 @@ struct davinci_i2c_dev { u8 *buf; size_t buf_len; int irq; + u8 terminate; struct i2c_adapter adapter; }; @@ -283,20 +285,34 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1); davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w); + dev->terminate = 0; /* write the data into mode register */ davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); r = wait_for_completion_interruptible_timeout(&dev->cmd_complete, DAVINCI_I2C_TIMEOUT); - dev->buf_len = 0; - if (r < 0) - return r; - if (r == 0) { dev_err(dev->dev, "controller timed out\n"); i2c_davinci_init(dev); + dev->buf_len = 0; return -ETIMEDOUT; } + if (dev->buf_len) { + /* This should be 0 if all bytes were transferred + * or dev->cmd_err denotes an error. + * A signal may have aborted the transfer. + */ + if (r >= 0) { + dev_err(dev->dev, "abnormal termination buf_len=%i\n", + dev->buf_len); + r = -EREMOTEIO; + } + dev->terminate = 1; + wmb(); + dev->buf_len = 0; + } + if (r < 0) + return r; /* no error */ if (likely(!dev->cmd_err)) @@ -354,6 +370,27 @@ static u32 i2c_davinci_func(struct i2c_adapter *adap) return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); } +static void terminate_read(struct davinci_i2c_dev *dev) +{ + u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); + w |= DAVINCI_I2C_MDR_NACK; + davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); + + /* Throw away data */ + davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG); + if (!dev->terminate) + dev_err(dev->dev, "RDR IRQ while no data requested\n"); +} +static void terminate_write(struct davinci_i2c_dev *dev) +{ + u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); + w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP; + davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); + + if (!dev->terminate) + dev_err(dev->dev, "TDR IRQ while no data to send\n"); +} + /* * Interrupt service routine. This gets called whenever an I2C interrupt * occurs. @@ -374,12 +411,15 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id) switch (stat) { case DAVINCI_I2C_IVR_AL: + /* Arbitration lost, must retry */ dev->cmd_err |= DAVINCI_I2C_STR_AL; + dev->buf_len = 0; complete(&dev->cmd_complete); break; case DAVINCI_I2C_IVR_NACK: dev->cmd_err |= DAVINCI_I2C_STR_NACK; + dev->buf_len = 0; complete(&dev->cmd_complete); break; @@ -401,9 +441,10 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id) davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, DAVINCI_I2C_IMR_RRDY); - } else - dev_err(dev->dev, "RDR IRQ while no " - "data requested\n"); + } else { + /* signal can terminate transfer */ + terminate_read(dev); + } break; case DAVINCI_I2C_IVR_XRDY: @@ -420,9 +461,10 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id) davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w); - } else - dev_err(dev->dev, "TDR IRQ while no data to " - "send\n"); + } else { + /* signal can terminate transfer */ + terminate_write(dev); + } break; case DAVINCI_I2C_IVR_SCD: |