IKXCLOCK-2713: Retry setrate's

If i2c communication fails while doing a set sample rate for a sensor
retry the same during suspend. It is seems that sometimes omap->M4
i2c bus dies for a brief period and then recovers. But during the failure
period if an app tries to turn off a sensor and this turn off fails,
it could lead to wakeups after omap suspend, and so this fix
retries setting the sample rate on suspend only if it had failed earlier.

Change-Id: I5874738a78ed900b1b039160f852031321dd2e30

1 files changed, 31 insertions, 11 deletions

diff --git a/drivers/misc/m4sensorhub_pedometer.c b/drivers/misc/m4sensorhub_pedometer.c
index e53d62dee15..de8564bc317 100644
--- a/drivers/misc/m4sensorhub_pedometer.c
+++ b/drivers/misc/m4sensorhub_pedometer.c
@@ -46,6 +46,8 @@ struct m4ped_driver_data {
 
 	struct m4sensorhub_pedometer_iio_data   iiodat;
 	int16_t         samplerate;
+	int16_t         latest_samplerate;
+
 	uint16_t        status;
 	struct m4sensorhub_pedometer_iio_data   base_dat;
 
@@ -182,7 +184,9 @@ static int m4ped_set_samplerate(struct iio_dev *iio, int16_t rate)
 	 * Currently, there is no concept of setting a sample rate for this
 	 * sensor, so this function only enables/disables interrupt reporting.
 	 */
-	dd->samplerate = rate;
+	dd->latest_samplerate = rate;
+	if (rate == dd->samplerate)
+		goto m4ped_set_samplerate_fail;
 
 	if (rate >= 0) {
 		/* Enable the IRQ if necessary */
@@ -204,15 +208,7 @@ static int m4ped_set_samplerate(struct iio_dev *iio, int16_t rate)
 			}
 
 			dd->status = dd->status | (1 << M4PED_IRQ_ENABLED_BIT);
-		}
-		/* When an app registers, there is no data reported
-		unless the user starts walking. But the application
-		would like to have atleast one set of data sent
-		immediately following the register */
-		err = m4ped_read_report_data(iio, dd);
-		if (err < 0) {
-			m4ped_err("%s:Failed to report pedo data\n", __func__);
-			goto m4ped_set_samplerate_fail;
+			dd->samplerate = rate;
 		}
 	} else {
 		/* Disable the IRQ if necessary */
@@ -234,6 +230,7 @@ static int m4ped_set_samplerate(struct iio_dev *iio, int16_t rate)
 			}
 
 			dd->status = dd->status & ~(1 << M4PED_IRQ_ENABLED_BIT);
+			dd->samplerate = rate;
 		}
 	}
 
@@ -283,6 +280,17 @@ static ssize_t m4ped_setrate_store(struct device *dev,
 		m4ped_err("%s: Failed to set sample rate.\n", __func__);
 		goto m4ped_enable_store_exit;
 	}
+	if (value >= 0) {
+		/* When an app registers, there is no data reported
+		unless the user starts walking. But the application
+		would like to have atleast one set of data sent
+		immediately following the register */
+		err = m4ped_read_report_data(iio, dd);
+		if (err < 0) {
+			m4ped_err("%s:Failed to report pedo data\n", __func__);
+			goto m4ped_enable_store_exit;
+		}
+	}
 
 m4ped_enable_store_exit:
 	if (err < 0) {
@@ -618,6 +626,7 @@ static int m4ped_probe(struct platform_device *pdev)
 	mutex_init(&(dd->mutex));
 	platform_set_drvdata(pdev, iio);
 	dd->samplerate = -1; /* We always start disabled */
+	dd->latest_samplerate = dd->samplerate;
 
 	err = m4ped_create_iiodev(iio); /* iio and dd are freed on fail */
 	if (err < 0) {
@@ -671,6 +680,17 @@ m4ped_remove_exit:
 	return 0;
 }
 
+static int m4ped_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct iio_dev *iio = platform_get_drvdata(pdev);
+	struct m4ped_driver_data *dd = iio_priv(iio);
+	mutex_lock(&(dd->mutex));
+	if (m4ped_set_samplerate(iio, dd->latest_samplerate) < 0)
+		m4ped_err("%s: setrate retry failed\n", __func__);
+	mutex_unlock(&(dd->mutex));
+	return 0;
+}
+
 static struct of_device_id m4pedometer_match_tbl[] = {
 	{ .compatible = "mot,m4pedometer" },
 	{},
@@ -680,7 +700,7 @@ static struct platform_driver m4ped_driver = {
 	.probe		= m4ped_probe,
 	.remove		= __exit_p(m4ped_remove),
 	.shutdown	= NULL,
-	.suspend	= NULL,
+	.suspend	= m4ped_suspend,
 	.resume		= NULL,
 	.driver		= {
 		.name	= M4PED_DRIVER_NAME,