iio: accel: kionix-kx022a: Add a function to retrieve number of bytes in buffer

Since Kionix accelerometers use various numbers of bits to report data, a
device-specific function is required.
Implement the function as a callback in the device-specific chip_info structure
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Signed-off-by: Mehdi Djait <mehdi.djait.k@gmail.com>
Link: https://lore.kernel.org/r/9c550fb28e34915d473e379f812c7753f7643bae.1694867379.git.mehdi.djait.k@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/accel/kionix-kx022a.c

@@ -585,26 +585,33 @@ static int kx022a_drop_fifo_contents(struct kx022a_data *data)
 	return regmap_write(data->regmap, data->chip_info->buf_clear, 0x0);
 }
 
+static int kx022a_get_fifo_bytes_available(struct kx022a_data *data)
+{
+	int ret, fifo_bytes;
+
+	ret = regmap_read(data->regmap, KX022A_REG_BUF_STATUS_1, &fifo_bytes);
+	if (ret) {
+		dev_err(data->dev, "Error reading buffer status\n");
+		return ret;
+	}
+
+	if (fifo_bytes == KX022A_FIFO_FULL_VALUE)
+		return KX022A_FIFO_MAX_BYTES;
+
+	return fifo_bytes;
+}
+
 static int __kx022a_fifo_flush(struct iio_dev *idev, unsigned int samples,
 			       bool irq)
 {
 	struct kx022a_data *data = iio_priv(idev);
-	struct device *dev = regmap_get_device(data->regmap);
 	uint64_t sample_period;
 	int count, fifo_bytes;
 	bool renable = false;
 	int64_t tstamp;
 	int ret, i;
 
-	ret = regmap_read(data->regmap, KX022A_REG_BUF_STATUS_1, &fifo_bytes);
-	if (ret) {
-		dev_err(dev, "Error reading buffer status\n");
-		return ret;
-	}
-
-	/* Let's not overflow if we for some reason get bogus value from i2c */
-	if (fifo_bytes == KX022A_FIFO_FULL_VALUE)
-		fifo_bytes = KX022A_FIFO_MAX_BYTES;
+	fifo_bytes = data->chip_info->get_fifo_bytes_available(data);
 
 	if (fifo_bytes % KX022A_FIFO_SAMPLES_SIZE_BYTES)
 		dev_warn(data->dev, "Bad FIFO alignment. Data may be corrupt\n");
@@ -1013,6 +1020,7 @@ const struct kx022a_chip_info kx022a_chip_info = {
 	.inc5				= KX022A_REG_INC5,
 	.inc6				= KX022A_REG_INC6,
 	.xout_l				= KX022A_REG_XOUT_L,
+	.get_fifo_bytes_available	= kx022a_get_fifo_bytes_available,
 };
 EXPORT_SYMBOL_NS_GPL(kx022a_chip_info, IIO_KX022A);
 

drivers/iio/accel/kionix-kx022a.h

@@ -76,6 +76,8 @@
 
 struct device;
 
+struct kx022a_data;
+
 /**
  * struct kx022a_chip_info - Kionix accelerometer chip specific information
  *
@@ -99,6 +101,9 @@ struct device;
  * @inc5:			interrupt control register 5
  * @inc6:			interrupt control register 6
  * @xout_l:			x-axis output least significant byte
+ * @get_fifo_bytes_available:	function pointer to get amount of acceleration
+ *				data bytes currently stored in the sensor's FIFO
+ *				buffer
  */
 struct kx022a_chip_info {
 	const char *name;
@@ -121,6 +126,7 @@ struct kx022a_chip_info {
 	u8 inc5;
 	u8 inc6;
 	u8 xout_l;
+	int (*get_fifo_bytes_available)(struct kx022a_data *);
 };
 
 int kx022a_probe_internal(struct device *dev, const struct kx022a_chip_info *chip_info);