From: David Daney <dda...@caviumnetworks.com>
CN3860 does not interrupt the CPU when the i2c status changes. If
we get a timeout, and see the status has in fact changed, we know we
have this problem, and drop back to polling.
Signed-off-by: David Daney <dda...@caviumnetworks.com>
Signed-off-by: Jan Glauber <jglau...@cavium.com>
---
drivers/i2c/busses/i2c-octeon.c | 46 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
index e3552e5..3c2f848 100644
--- a/drivers/i2c/busses/i2c-octeon.c
+++ b/drivers/i2c/busses/i2c-octeon.c
@@ -115,6 +115,7 @@ struct octeon_i2c {
int sys_freq;
void __iomem *twsi_base;
struct device *dev;
+ int broken_irq_mode;
bool hlc_enabled;
void (*int_en) (struct octeon_i2c *);
void (*int_dis) (struct octeon_i2c *);
@@ -382,10 +383,33 @@ static int octeon_i2c_wait(struct octeon_i2c *i2c)
int first = 1;
long result;
+ if (i2c->broken_irq_mode) {
+ /*
+ * Some chip revisions seem to not assert the irq in
+ * the interrupt controller. So we must poll for the
+ * IFLG change.
+ */
+ u64 end = get_jiffies_64() + i2c->adap.timeout;
+
+ while (!octeon_i2c_test_iflg(i2c) &&
+ time_before64(get_jiffies_64(), end))
+ udelay(50);
+
+ return octeon_i2c_test_iflg(i2c) ? 0 : -ETIMEDOUT;
+ }
+
i2c->int_en(i2c);
result = wait_event_timeout(i2c->queue, poll_iflg(i2c, &first),
i2c->adap.timeout);
i2c->int_dis(i2c);
+
+ if (result <= 0 && OCTEON_IS_MODEL(OCTEON_CN38XX) &&
+ octeon_i2c_test_iflg(i2c)) {
+ dev_err(i2c->dev,
+ "broken irq connection detected, switching to polling
mode.\n");
+ i2c->broken_irq_mode = 1;
+ return 0;
+ }
if (!result) {
dev_dbg(i2c->dev, "%s: timeout\n", __func__);
return -ETIMEDOUT;
@@ -740,6 +764,21 @@ static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c)
{
int result;
+ if (i2c->broken_irq_mode) {
+ /*
+ * Some cn38xx boards did not assert the irq in
+ * the interrupt controller. So we must poll for the
+ * IFLG change.
+ */
+ u64 end = get_jiffies_64() + i2c->adap.timeout;
+
+ while (!octeon_i2c_hlc_test_ready(i2c) &&
+ time_before64(get_jiffies_64(), end))
+ udelay(50);
+
+ return octeon_i2c_hlc_test_ready(i2c) ? 0 : -ETIMEDOUT;
+ }
+
i2c->hlc_int_en(i2c);
result = wait_event_interruptible_timeout(i2c->queue,
octeon_i2c_hlc_test_ready(i2c), i2c->adap.timeout);
@@ -747,6 +786,13 @@ static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c)
if (!result)
octeon_i2c_hlc_int_clear(i2c);
+ if (result <= 0 && OCTEON_IS_MODEL(OCTEON_CN38XX) &&
+ octeon_i2c_hlc_test_ready(i2c)) {
+ dev_err(i2c->dev, "broken irq connection detected, switching to
polling mode.\n");
+ i2c->broken_irq_mode = 1;
+ return 0;
+ }
+
if (result < 0) {
dev_dbg(i2c->dev, "%s: wait interrupted\n", __func__);
return result;
--
1.9.1
