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path: root/drivers/i2c/busses/i2c-davinci.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-davinci.c')
-rw-r--r--drivers/i2c/busses/i2c-davinci.c89
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);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.