This patch includes the workarround for I2C Errata 1.153: When an XRDY/XDR is hit, wait for XUDF before writing data to DATA_REG
Signed-off-by: Jagadeesh Bhaskar Pakaravoor <j-pakaravoor@xxxxxx>
Signed-off by: Nishant Kamat <nskamat@xxxxxx>
Signed-off-by: Moiz Sonasath<m-sonasath@xxxxxx>
---
drivers/i2c/busses/i2c-omap.c | 54 +++++++++++++++++++++++++++++++++++++---
1 files changed, 50 insertions(+), 4 deletions(-)
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index ece0125..e84836b 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -632,6 +632,37 @@ omap_i2c_rev1_isr(int this_irq, void *dev_id)
#define omap_i2c_rev1_isr NULL
#endif
+/* I2C Errata 1.153:
+ * When an XRDY/XDR is hit, wait for XUDF before writing data to DATA_REG.
+ * Otherwise some data bytes can be lost while transferring them from the
+ * memory to the I2C interface.
+ */
+
+static int omap_i2c_wait_for_xudf(struct omap_i2c_dev *dev)
+{
+ u16 xudf;
+ int counter = 500;
+
+ /* We are in interrupt context. Wait for XUDF for max 7 msec */
+ xudf = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
+ while (!(xudf & OMAP_I2C_STAT_XUDF) && counter--) {
+ if (xudf & (OMAP_I2C_STAT_ROVR | OMAP_I2C_STAT_NACK |
+ OMAP_I2C_STAT_AL))
+ return -EINVAL;
+ udelay(10);
+ xudf = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
+ }
+
+ if (!counter) {
+ /* Clear Tx FIFO */
+ omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG,
+ OMAP_I2C_BUF_TXFIF_CLR);
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
static irqreturn_t
omap_i2c_isr(int this_irq, void *dev_id)
{
@@ -639,6 +670,7 @@ omap_i2c_isr(int this_irq, void *dev_id)
u16 bits;
u16 stat, w;
int err, count = 0;
+ int error;
if (dev->idle)
return IRQ_NONE;
@@ -647,7 +679,7 @@ omap_i2c_isr(int this_irq, void *dev_id)
while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) {
dev_dbg(dev->dev, "IRQ (ISR = 0x%04x)\n", stat);
if (count++ == 100) {
- dev_warn(dev->dev, "Too much work in one IRQ\n");
+ dev_dbg(dev->dev, "Too much work in one IRQ\n");
break;
}
@@ -715,11 +747,22 @@ omap_i2c_isr(int this_irq, void *dev_id)
OMAP_I2C_BUFSTAT_REG);
}
while (num_bytes) {
- num_bytes--;
w = 0;
if (dev->buf_len) {
+ if (cpu_is_omap34xx()) {
+ /* OMAP3430 Errata 1.153 */
+ error = omap_i2c_wait_for_xudf(dev);
+ if (error) {
+ omap_i2c_ack_stat(dev, stat &
+ (OMAP_I2C_STAT_XRDY |
+ OMAP_I2C_STAT_XDR));
+ dev_err(dev->dev, "Transmit error\n");
+ omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_XUDF);
+
+ return IRQ_HANDLED;
+ }
+ }
w = *dev->buf++;
- dev->buf_len--;
/* Data reg from 2430 is 8 bit wide */
if (!cpu_is_omap2430() &&
!cpu_is_omap34xx()) {
@@ -728,6 +771,10 @@ omap_i2c_isr(int this_irq, void *dev_id)
dev->buf_len--;
}
}
+ omap_i2c_write_reg(dev,
+ OMAP_I2C_DATA_REG, w);
+ num_bytes--;
+ dev->buf_len--;
} else {
if (stat & OMAP_I2C_STAT_XRDY)
dev_err(dev->dev,
@@ -739,7 +786,6 @@ omap_i2c_isr(int this_irq, void *dev_id)
"data to send\n");
break;
}
- omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
}
omap_i2c_ack_stat(dev,
stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
--
1.5.6.3
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