[PATCH v8 2/2] iio: pressure: dps310: Reset chip after timeout

Eddie James
2022-09-15T19:57:56Z

The DPS310 chip has been observed to get "stuck" such that pressure
and temperature measurements are never indicated as "ready" in the
MEAS_CFG register. The only solution is to reset the device and try
again. In order to avoid continual failures, use a boolean flag to
only try the reset after timeout once if errors persist.

Fixes: ba6ec48e76bc ("iio: Add driver for Infineon DPS310")
Cc: <stable@vger.kernel.org>
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
drivers/iio/pressure/dps310.c | 74 ++++++++++++++++++++++++++++++-----
1 file changed, 64 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/pressure/dps310.c b/drivers/iio/pressure/dps310.c
index c706a8b423b5..984a3f511a1a 100644
--- a/drivers/iio/pressure/dps310.c
+++ b/drivers/iio/pressure/dps310.c
@@ -89,6 +89,7 @@ struct dps310_data {
s32 c00, c10, c20, c30, c01, c11, c21;
s32 pressure_raw;
s32 temp_raw;
+ bool timeout_recovery_failed;
};

static const struct iio_chan_spec dps310_channels[] = {
@@ -393,11 +394,69 @@ static int dps310_get_temp_k(struct dps310_data *data)
return scale_factors[ilog2(rc)];
}

+static int dps310_reset_wait(struct dps310_data *data)
+{
+ int rc;
+
+ rc = regmap_write(data->regmap, DPS310_RESET, DPS310_RESET_MAGIC);
+ if (rc)
+ return rc;
+
+ /* Wait for device chip access: 2.5ms in specification */
+ usleep_range(2500, 12000);
+ return 0;
+}
+
+static int dps310_reset_reinit(struct dps310_data *data)
+{
+ int rc;
+
+ rc = dps310_reset_wait(data);
+ if (rc)
+ return rc;
+
+ return dps310_startup(data);
+}
+
+static int dps310_ready_status(struct dps310_data *data, int ready_bit, int timeout)
+{
+ int sleep = DPS310_POLL_SLEEP_US(timeout);
+ int ready;
+
+ return regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready, ready & ready_bit,
+ sleep, timeout);
+}
+
+static int dps310_ready(struct dps310_data *data, int ready_bit, int timeout)
+{
+ int rc;
+
+ rc = dps310_ready_status(data, ready_bit, timeout);
+ if (rc) {
+ if (rc == -ETIMEDOUT && !data->timeout_recovery_failed) {
+ /* Reset and reinitialize the chip. */
+ if (dps310_reset_reinit(data)) {
+ data->timeout_recovery_failed = true;
+ } else {
+ /* Try again to get sensor ready status. */
+ if (dps310_ready_status(data, ready_bit, timeout))
+ data->timeout_recovery_failed = true;
+ else
+ return 0;
+ }
+ }
+
+ return rc;
+ }
+
+ data->timeout_recovery_failed = false;
+ return 0;
+}
+
static int dps310_read_pres_raw(struct dps310_data *data)
{
int rc;
int rate;
- int ready;
int timeout;
s32 raw;
u8 val[3];
@@ -409,9 +468,7 @@ static int dps310_read_pres_raw(struct dps310_data *data)
timeout = DPS310_POLL_TIMEOUT_US(rate);

/* Poll for sensor readiness; base the timeout upon the sample rate. */
- rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
- ready & DPS310_PRS_RDY,
- DPS310_POLL_SLEEP_US(timeout), timeout);
+ rc = dps310_ready(data, DPS310_PRS_RDY, timeout);
if (rc)
goto done;

@@ -448,7 +505,6 @@ static int dps310_read_temp_raw(struct dps310_data *data)
{
int rc;
int rate;
- int ready;
int timeout;

if (mutex_lock_interruptible(&data->lock))
@@ -458,10 +514,8 @@ static int dps310_read_temp_raw(struct dps310_data *data)
timeout = DPS310_POLL_TIMEOUT_US(rate);

/* Poll for sensor readiness; base the timeout upon the sample rate. */
- rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
- ready & DPS310_TMP_RDY,
- DPS310_POLL_SLEEP_US(timeout), timeout);
- if (rc < 0)
+ rc = dps310_ready(data, DPS310_TMP_RDY, timeout);
+ if (rc)
goto done;

rc = dps310_read_temp_ready(data);
@@ -756,7 +810,7 @@ static void dps310_reset(void *action_data)
{
struct dps310_data *data = action_data;

- regmap_write(data->regmap, DPS310_RESET, DPS310_RESET_MAGIC);
+ dps310_reset_wait(data);
}

static const struct regmap_config dps310_regmap_config = {
--
2.31.1