1 files changed, 67 insertions, 22 deletions

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 7ecbfc429b19..af3846eda985 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;
 };
 
@@ -142,6 +144,7 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
         struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
         u16 psc;
         u32 clk;
+        u32 d;
         u32 clkh;
         u32 clkl;
         u32 input_clock = clk_get_rate(dev->clk);
@@ -171,23 +174,29 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
          *       if PSC > 1 , d = 5
          */
 
-        psc = 26; /* To get 1MHz clock */
+        /* get minimum of 7 MHz clock, but max of 12 MHz */
+        psc = (input_clock / 7000000) - 1;
+        if ((input_clock / (psc + 1)) > 12000000)
+                psc++;  /* better to run under spec than over */
+        d = (psc >= 2) ? 5 : 7 - psc;
 
-        clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - 10;
-        clkh = (50 * clk) / 100;
+        clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1);
+        clkh = clk >> 1;
         clkl = clk - clkh;
 
         davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
 
-        dev_dbg(dev->dev, "CLK  = %d\n", clk);
+        dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
         dev_dbg(dev->dev, "PSC  = %d\n",
                 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
         dev_dbg(dev->dev, "CLKL = %d\n",
                 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
         dev_dbg(dev->dev, "CLKH = %d\n",
                 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
+        dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
+                pdata->bus_freq, pdata->bus_delay);
 
         /* Take the I2C module out of reset: */
         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
@@ -233,7 +242,6 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
         struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
         struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
         u32 flag;
-        u32 stat;
         u16 w;
         int r;
 
@@ -254,12 +262,9 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 
         davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
 
-        init_completion(&dev->cmd_complete);
+        INIT_COMPLETION(dev->cmd_complete);
         dev->cmd_err = 0;
 
-        /* Clear any pending interrupts by reading the IVR */
-        stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG);
-
         /* Take I2C out of reset, configure it as master and set the
          * start bit */
         flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST | DAVINCI_I2C_MDR_STT;
@@ -280,20 +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))
@@ -338,12 +357,11 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 
         for (i = 0; i < num; i++) {
                 ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
+                dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
+                        ret);
                 if (ret < 0)
                         return ret;
         }
-
-        dev_dbg(dev->dev, "%s:%d ret: %d\n", __func__, __LINE__, ret);
-
         return num;
 }
 
@@ -352,6 +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.
@@ -372,12 +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;
 
@@ -399,9 +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:
@@ -418,9 +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:
@@ -475,6 +519,7 @@ static int davinci_i2c_probe(struct platform_device *pdev)
                 goto err_release_region;
         }
 
+        init_completion(&dev->cmd_complete);
         dev->dev = get_device(&pdev->dev);
         dev->irq = irq->start;
         platform_set_drvdata(pdev, dev);