[PATCH v2 4/5] iio: accel: kionix-kx022a: Add a function to retrieve number of bytes in buffer

Mehdi Djait
2023-04-20T20:23:17Z

Since Kionix accelerometers use various numbers of bits to report data, a
device-specific function is required.
Move the driver's private data to the header file to support the new function.
Make the allocation of the "buffer" array in the fifo_flush function dynamic
and more generic.

Signed-off-by: Mehdi Djait <mehdi.djait.k@gmail.com>
---
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 | 72 +++++++++++++------------------
drivers/iio/accel/kionix-kx022a.h | 37 ++++++++++++++++
2 files changed, 66 insertions(+), 43 deletions(-)

diff --git a/drivers/iio/accel/kionix-kx022a.c b/drivers/iio/accel/kionix-kx022a.c
index 7f9a2c29790b..1c81ea1657b9 100644
--- a/drivers/iio/accel/kionix-kx022a.c
+++ b/drivers/iio/accel/kionix-kx022a.c
@@ -150,36 +150,6 @@ static const struct regmap_config kx022a_regmap_config = {
.cache_type = REGCACHE_RBTREE,
};

-struct kx022a_data {
- struct regmap *regmap;
- struct iio_trigger *trig;
- struct device *dev;
- struct iio_mount_matrix orientation;
- int64_t timestamp, old_timestamp;
-
- int irq;
- int inc_reg;
- int ien_reg;
-
- unsigned int state;
- unsigned int odr_ns;
-
- bool trigger_enabled;
- /*
- * Prevent toggling the sensor stby/active state (PC1 bit) in the
- * middle of a configuration, or when the fifo is enabled. Also,
- * protect the data stored/retrieved from this structure from
- * concurrent accesses.
- */
- struct mutex mutex;
- u8 watermark;
-
- /* 3 x 16bit accel data + timestamp */
- __le16 buffer[8] __aligned(IIO_DMA_MINALIGN);
- struct {
- __le16 channels[3];
- s64 ts __aligned(8);
- } scan;
};

static const struct iio_mount_matrix *
@@ -340,7 +310,6 @@ static int kx022a_turn_on_off_unlocked(struct kx022a_data *data, bool on)
dev_err(data->dev, "Turn %s fail %d\n", str_on_off(on), ret);

return ret;
-
}

static int kx022a_turn_off_lock(struct kx022a_data *data)
@@ -595,34 +564,50 @@ 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)
+{
+ struct device *dev = regmap_get_device(data->regmap);
+ int ret, fifo_bytes;
+
+ 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;
+
+ 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);
- __le16 buffer[KX022A_FIFO_LENGTH * 3];
+ __le16 *buffer;
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;
- }
+ /* 3 axis, 2 bytes of data for each of the axis */
+ buffer = kmalloc(data->chip_info->fifo_length * 6, GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;

- /* 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");

count = fifo_bytes / KX022A_FIFO_SAMPLES_SIZE_BYTES;
- if (!count)
+ if (!count) {
+ kfree(buffer);
return 0;
+ }

/*
* If we are being called from IRQ handler we know the stored timestamp
@@ -704,6 +689,7 @@ static int __kx022a_fifo_flush(struct iio_dev *idev, unsigned int samples,
if (renable)
enable_irq(data->irq);

+ kfree(buffer);
return ret;
}

@@ -1016,6 +1002,7 @@ 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);

@@ -1143,7 +1130,6 @@ int kx022a_probe_internal(struct device *dev, const struct kx022a_chip_info *chi
if (ret)
return dev_err_probe(data->dev, ret, "Could not request IRQ\n");

-
ret = devm_iio_trigger_register(dev, indio_trig);
if (ret)
return dev_err_probe(data->dev, ret,
diff --git a/drivers/iio/accel/kionix-kx022a.h b/drivers/iio/accel/kionix-kx022a.h
index 3c31e7d88f78..43e32e688258 100644
--- a/drivers/iio/accel/kionix-kx022a.h
+++ b/drivers/iio/accel/kionix-kx022a.h
@@ -11,6 +11,8 @@
#include <linux/bits.h>
#include <linux/regmap.h>

+#include <linux/iio/iio.h>
+
#define KX022A_REG_WHO 0x0f
#define KX022A_ID 0xc8

@@ -76,6 +78,39 @@

struct device;

+struct kx022a_data {
+ const struct kx022a_chip_info *chip_info;
+ struct regmap *regmap;
+ struct iio_trigger *trig;
+ struct device *dev;
+ struct iio_mount_matrix orientation;
+ int64_t timestamp, old_timestamp;
+
+ int irq;
+ int inc_reg;
+ int ien_reg;
+
+ unsigned int state;
+ unsigned int odr_ns;
+
+ bool trigger_enabled;
+ /*
+ * Prevent toggling the sensor stby/active state (PC1 bit) in the
+ * middle of a configuration, or when the fifo is enabled. Also,
+ * protect the data stored/retrieved from this structure from
+ * concurrent accesses.
+ */
+ struct mutex mutex;
+ u8 watermark;
+
+ /* 3 x 16bit accel data + timestamp */
+ __le16 buffer[8] __aligned(IIO_DMA_MINALIGN);
+ struct {
+ __le16 channels[3];
+ s64 ts __aligned(8);
+ } scan;
+};
+
/**
* struct kx022a_chip_info - Kionix accelerometer chip specific information
*
@@ -100,6 +135,7 @@ 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;
@@ -123,6 +159,7 @@ 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