[PATCH 4.19 123/125] iio: imu: inv_mpu6050: fix no data on MPU6050

From: Greg Kroah-Hartman
Date: Mon Nov 11 2019 - 13:47:28 EST


From: Jean-Baptiste Maneyrol <JManeyrol@xxxxxxxxxxxxxx>

[ Upstream commit 6e82ae6b8d11b948b74e71396efd8e074c415f44 ]

Some chips have a fifo overflow bit issue where the bit is always
set. The result is that every data is dropped.

Change fifo overflow management by checking fifo count against
a maximum value.

Add fifo size in chip hardware set of values.

Fixes: f5057e7b2dba ("iio: imu: inv_mpu6050: better fifo overflow handling")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@xxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/iio/imu/inv_mpu6050/inv_mpu_core.c | 9 +++++++++
drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h | 2 ++
drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c | 15 ++++++++++++---
3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
index cb80c9e49fc7b..ea099523e0355 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
@@ -121,54 +121,63 @@ static const struct inv_mpu6050_hw hw_info[] = {
.name = "MPU6050",
.reg = &reg_set_6050,
.config = &chip_config_6050,
+ .fifo_size = 1024,
},
{
.whoami = INV_MPU6500_WHOAMI_VALUE,
.name = "MPU6500",
.reg = &reg_set_6500,
.config = &chip_config_6050,
+ .fifo_size = 512,
},
{
.whoami = INV_MPU6515_WHOAMI_VALUE,
.name = "MPU6515",
.reg = &reg_set_6500,
.config = &chip_config_6050,
+ .fifo_size = 512,
},
{
.whoami = INV_MPU6000_WHOAMI_VALUE,
.name = "MPU6000",
.reg = &reg_set_6050,
.config = &chip_config_6050,
+ .fifo_size = 1024,
},
{
.whoami = INV_MPU9150_WHOAMI_VALUE,
.name = "MPU9150",
.reg = &reg_set_6050,
.config = &chip_config_6050,
+ .fifo_size = 1024,
},
{
.whoami = INV_MPU9250_WHOAMI_VALUE,
.name = "MPU9250",
.reg = &reg_set_6500,
.config = &chip_config_6050,
+ .fifo_size = 512,
},
{
.whoami = INV_MPU9255_WHOAMI_VALUE,
.name = "MPU9255",
.reg = &reg_set_6500,
.config = &chip_config_6050,
+ .fifo_size = 512,
},
{
.whoami = INV_ICM20608_WHOAMI_VALUE,
.name = "ICM20608",
.reg = &reg_set_6500,
.config = &chip_config_6050,
+ .fifo_size = 512,
},
{
.whoami = INV_ICM20602_WHOAMI_VALUE,
.name = "ICM20602",
.reg = &reg_set_icm20602,
.config = &chip_config_6050,
+ .fifo_size = 1008,
},
};

diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
index bdbaf6e01ce3e..e56c1d191ae46 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
@@ -108,12 +108,14 @@ struct inv_mpu6050_chip_config {
* @name: name of the chip.
* @reg: register map of the chip.
* @config: configuration of the chip.
+ * @fifo_size: size of the FIFO in bytes.
*/
struct inv_mpu6050_hw {
u8 whoami;
u8 *name;
const struct inv_mpu6050_reg_map *reg;
const struct inv_mpu6050_chip_config *config;
+ size_t fifo_size;
};

/*
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
index 548e042f7b5bd..4f9c2765aa23f 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
@@ -188,9 +188,6 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
"failed to ack interrupt\n");
goto flush_fifo;
}
- /* handle fifo overflow by reseting fifo */
- if (int_status & INV_MPU6050_BIT_FIFO_OVERFLOW_INT)
- goto flush_fifo;
if (!(int_status & INV_MPU6050_BIT_RAW_DATA_RDY_INT)) {
dev_warn(regmap_get_device(st->map),
"spurious interrupt with status 0x%x\n", int_status);
@@ -216,6 +213,18 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
if (result)
goto end_session;
fifo_count = get_unaligned_be16(&data[0]);
+
+ /*
+ * Handle fifo overflow by resetting fifo.
+ * Reset if there is only 3 data set free remaining to mitigate
+ * possible delay between reading fifo count and fifo data.
+ */
+ nb = 3 * bytes_per_datum;
+ if (fifo_count >= st->hw->fifo_size - nb) {
+ dev_warn(regmap_get_device(st->map), "fifo overflow reset\n");
+ goto flush_fifo;
+ }
+
/* compute and process all complete datum */
nb = fifo_count / bytes_per_datum;
inv_mpu6050_update_period(st, pf->timestamp, nb);
--
2.20.1