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From:   Mehdi Djait <mehdi.djait.k@gmail.com>
To:     jic23@kernel.org, mazziesaccount@gmail.com
Cc:     krzysztof.kozlowski+dt@linaro.org,
        andriy.shevchenko@linux.intel.com, linux-iio@vger.kernel.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        Mehdi Djait <mehdi.djait.k@gmail.com>
Subject: [PATCH v2 4/5] iio: accel: kionix-kx022a: Add a function to retrieve number of bytes in buffer
Date:   Thu, 20 Apr 2023 22:22:04 +0200
Message-Id: <2c5d71e37fc7e000091189b3c5d66ede1a6015d2.1682019544.git.mehdi.djait.k@gmail.com>
In-Reply-To: <cover.1682019544.git.mehdi.djait.k@gmail.com>
References: <cover.1682019544.git.mehdi.djait.k@gmail.com>
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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