iio: cros_ec: Use default frequencies when EC returns invalid information

Minimal and maximal frequencies supported by a sensor is queried.
On some older machines, these frequencies are not returned properly and
the EC returns 0 instead.
When returned maximal frequency is 0, ignore the information and use
default frequencies instead.

Fixes: ae7b02ad ("iio: common: cros_ec_sensors: Expose cros_ec_sensors frequency range via iio sysfs")
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20200630153730.3302889-1-gwendal@chromium.org
CC: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c

@@ -256,7 +256,7 @@ int cros_ec_sensors_core_init(struct platform_device *pdev,
 	struct cros_ec_sensorhub *sensor_hub = dev_get_drvdata(dev->parent);
 	struct cros_ec_dev *ec = sensor_hub->ec;
 	struct cros_ec_sensor_platform *sensor_platform = dev_get_platdata(dev);
-	u32 ver_mask;
+	u32 ver_mask, temp;
 	int frequencies[ARRAY_SIZE(state->frequencies) / 2] = { 0 };
 	int ret, i;
 
@@ -311,10 +311,16 @@ int cros_ec_sensors_core_init(struct platform_device *pdev,
 						 &frequencies[2],
 						 &state->fifo_max_event_count);
 		} else {
-			frequencies[1] = state->resp->info_3.min_frequency;
-			frequencies[2] = state->resp->info_3.max_frequency;
-			state->fifo_max_event_count =
-			    state->resp->info_3.fifo_max_event_count;
+			if (state->resp->info_3.max_frequency == 0) {
+				get_default_min_max_freq(state->resp->info.type,
+							 &frequencies[1],
+							 &frequencies[2],
+							 &temp);
+			} else {
+				frequencies[1] = state->resp->info_3.min_frequency;
+				frequencies[2] = state->resp->info_3.max_frequency;
+			}
+			state->fifo_max_event_count = state->resp->info_3.fifo_max_event_count;
 		}
 		for (i = 0; i < ARRAY_SIZE(frequencies); i++) {
 			state->frequencies[2 * i] = frequencies[i] / 1000;