[PATCH v7 6/7] iio: accel: kionix-kx022a: Add a function to retrieve number of bytes in buffer

[Mehdi Djait <mehdi.djait.k@xxxxxxxxx>]

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@xxxxxxxxx>
Signed-off-by: Mehdi Djait <mehdi.djait.k@xxxxxxxxx>
---
v7:
- no changes

v6:
- directly return KX022A_FIFO_MAX_BYTES as suggested by Andy

v5:
- no changes

v4:
- removed the comment about "bogus value from i2c"
- removed regmap_get_device(data->regmap); dev is present in the
  driver's private data

v3:
- no changes

v2:
- separated this change from the chip_info introduction and made it a patch in v2 
- changed the function from generic implementation for to device-specific one
- removed blank lines pointed out by checkpatch
- changed the allocation of the "buffer" array in __kx022a_fifo_flush

 drivers/iio/accel/kionix-kx022a.c | 28 ++++++++++++++++++----------
 drivers/iio/accel/kionix-kx022a.h |  4 ++++
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/accel/kionix-kx022a.c b/drivers/iio/accel/kionix-kx022a.c
index 0bab3f109e4e..0b0f14dca17f 100644
--- a/drivers/iio/accel/kionix-kx022a.c
+++ b/drivers/iio/accel/kionix-kx022a.c
@@ -596,26 +596,33 @@ 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(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(data);
 
 	if (fifo_bytes % KX022A_FIFO_SAMPLES_SIZE_BYTES)
 		dev_warn(data->dev, "Bad FIFO alignment. Data may be corrupt\n");
@@ -1023,6 +1030,7 @@ 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	  = kx022a_get_fifo_bytes,
 };
 EXPORT_SYMBOL_NS_GPL(kx022a_chip_info, IIO_KX022A);
 
diff --git a/drivers/iio/accel/kionix-kx022a.h b/drivers/iio/accel/kionix-kx022a.h
index 0e5026019213..c9f9aee7e597 100644
--- a/drivers/iio/accel/kionix-kx022a.h
+++ b/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 +101,7 @@ struct device;
  * @inc5:		interrupt control register 5
  * @inc6:		interrupt control register 6
  * @xout_l:		x-axis output least significant byte
+ * @get_fifo_bytes:	function pointer to get number of bytes in the FIFO buffer
  */
 struct kx022a_chip_info {
 	const char *name;
@@ -121,6 +124,7 @@ struct kx022a_chip_info {
 	u8 inc5;
 	u8 inc6;
 	u8 xout_l;
+	int (*get_fifo_bytes)(struct kx022a_data *);
 };
 
 int kx022a_probe_internal(struct device *dev, const struct kx022a_chip_info *chip_info);
-- 
2.30.2