Sonasath, Moiz wrote:
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.
Do a Busy-wait for XUDF, before writing data to DATA_REG. While waiting
if there is NACK | AL, set the appropriate error flags, ack the pending
interrupts and return from the ISR.
Signed-off-by: Moiz Sonasath<m-sonasath@xxxxxx>
Signed-off-by: Vikram Pandita<vikram.pandita@xxxxxx>
---
drivers/i2c/busses/i2c-omap.c | 24 +++++++++++++++++++++++-
1 files changed, 23 insertions(+), 1 deletions(-)
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 05b5e4c..8deaf87 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -672,9 +672,10 @@ omap_i2c_isr(int this_irq, void *dev_id)
break;
}
+ err = 0;
+complete:
cant we rename this label?
omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
- err = 0;
if (stat & OMAP_I2C_STAT_NACK) {
err |= OMAP_I2C_STAT_NACK;
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
@@ -764,6 +765,27 @@ omap_i2c_isr(int this_irq, void *dev_id)
"data to send\n");
break;
}
+
+ /*
+ * OMAP3430 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.
+ */
+
+ if (cpu_is_omap34xx()) {
+ while (!(stat & OMAP_I2C_STAT_XUDF)) {
+ if (stat & (OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) {
+ omap_i2c_ack_stat(dev, stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
generic comment - code nesting is getting overwhelming - we may like to
refactor the isr function at a later date I think..
+ err |= OMAP_I2C_STAT_XUDF;
why set the err if we wantedly force this to happen?
+ goto complete;
+ }
+ cpu_relax();
+ stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
+ }
this is an infinite while loop + it tries to handle error cases -
essentially do another isr routine inside itself.
How about:
Apply [1] and the following?
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index ad8d201..e3f21af 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -728,6 +728,12 @@ omap_i2c_isr(int this_irq, void *dev_id)
}
if (stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR)) {
u8 num_bytes = 1;
+ if (cpu_is_omap34xx() &&
+ !(stat & OMAP_I2C_STAT_XUDF)){
+ cpu_relax();
+ continue;
+ }
+
if (dev->fifo_size) {
if (stat & OMAP_I2C_STAT_XRDY)
num_bytes = dev->fifo_size;
Regards,
Nishanth Menon
Ref:
[1] http://patchwork.kernel.org/patch/32332/
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