From 6e82ae6b8d11b948b74e71396efd8e074c415f44 Mon Sep 17 00:00:00 2001 From: Jean-Baptiste Maneyrol Date: Wed, 16 Oct 2019 14:43:28 +0000 Subject: iio: imu: inv_mpu6050: fix no data on MPU6050 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@vger.kernel.org Signed-off-by: Jean-Baptiste Maneyrol Signed-off-by: Jonathan Cameron --- drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c') diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c index 5f9a5de0bab4..72d8c5790076 100644 --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c @@ -180,9 +180,6 @@ 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); @@ -211,6 +208,18 @@ 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); -- cgit