iio: temperature: mlx90632 Read sampling frequency

Allow users to read sensor sampling frequency to better plan the
application measurement requests.
Signed-off-by: Crt Mori <cmo@melexis.com>
Link: https://lore.kernel.org/r/0bd6d6d665b4bd39e4565f6f44cb1bdc03386e23.1663834141.git.cmo@melexis.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/temperature/mlx90632.c

@@ -81,6 +81,9 @@
 #define MLX90632_PWR_STATUS_CONTINUOUS MLX90632_PWR_STATUS(3) /* continuous */
 
 #define MLX90632_EE_RR GENMASK(10, 8) /* Only Refresh Rate bits */
+#define MLX90632_REFRESH_RATE(ee_val) FIELD_GET(MLX90632_EE_RR, ee_val)
+					/* Extract Refresh Rate from ee register */
+#define MLX90632_REFRESH_RATE_STATUS(refresh_rate) (refresh_rate << 8)
 
 /* Measurement types */
 #define MLX90632_MTYP_MEDICAL 0
@@ -914,6 +917,32 @@ static int mlx90632_calc_ambient_dsp105(struct mlx90632_data *data, int *val)
 	return ret;
 }
 
+static int mlx90632_get_refresh_rate(struct mlx90632_data *data,
+				     int *refresh_rate)
+{
+	unsigned int meas1;
+	int ret;
+
+	ret = regmap_read(data->regmap, MLX90632_EE_MEDICAL_MEAS1, &meas1);
+	if (ret < 0)
+		return ret;
+
+	*refresh_rate = MLX90632_REFRESH_RATE(meas1);
+
+	return ret;
+}
+
+static const int mlx90632_freqs[][2] = {
+	{0, 500000},
+	{1, 0},
+	{2, 0},
+	{4, 0},
+	{8, 0},
+	{16, 0},
+	{32, 0},
+	{64, 0}
+};
+
 /**
  * mlx90632_pm_interraction_wakeup() - Measure time between user interactions to change powermode
  * @data: pointer to mlx90632_data object containing interaction_ts information
@@ -992,6 +1021,15 @@ static int mlx90632_read_raw(struct iio_dev *indio_dev,
 		*val = data->object_ambient_temperature;
 		ret = IIO_VAL_INT;
 		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret = mlx90632_get_refresh_rate(data, &cr);
+		if (ret < 0)
+			goto mlx90632_read_raw_pm;
+
+		*val = mlx90632_freqs[cr][0];
+		*val2 = mlx90632_freqs[cr][1];
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		break;
 	default:
 		ret = -EINVAL;
 		break;
@@ -1025,12 +1063,30 @@ static int mlx90632_write_raw(struct iio_dev *indio_dev,
 	}
 }
 
+static int mlx90632_read_avail(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       const int **vals, int *type, int *length,
+			       long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*vals = (int *)mlx90632_freqs;
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		*length = 2 * ARRAY_SIZE(mlx90632_freqs);
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
+
 static const struct iio_chan_spec mlx90632_channels[] = {
 	{
 		.type = IIO_TEMP,
 		.modified = 1,
 		.channel2 = IIO_MOD_TEMP_AMBIENT,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	},
 	{
 		.type = IIO_TEMP,
@@ -1038,12 +1094,15 @@ static const struct iio_chan_spec mlx90632_channels[] = {
 		.channel2 = IIO_MOD_TEMP_OBJECT,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 			BIT(IIO_CHAN_INFO_CALIBEMISSIVITY) | BIT(IIO_CHAN_INFO_CALIBAMBIENT),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	},
 };
 
 static const struct iio_info mlx90632_info = {
 	.read_raw = mlx90632_read_raw,
 	.write_raw = mlx90632_write_raw,
+	.read_avail = mlx90632_read_avail,
 };
 
 static void mlx90632_sleep(void *_data)