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iio: accel: fxls8962af: fix errata bug E3 - I2C burst reads

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When flushing the hw fifo there is a bug in the I2C that prevents burst
reads of more than one sample pair.

Signed-off-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Sean Nyekjaer 2021-05-06 09:09:40 +02:00 committed by Jonathan Cameron
parent 79e3a5bdd9
commit af959b7b96
1 changed files with 30 additions and 3 deletions
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33
drivers/iio/accel/fxls8962af-core.c
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@ -14,6 +14,7 @@
#include <linux/bits.h> #include <linux/bits.h>
#include <linux/bitfield.h> #include <linux/bitfield.h>
#include <linux/i2c.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/of_irq.h> #include <linux/of_irq.h>
#include <linux/pm_runtime.h> #include <linux/pm_runtime.h>
@ -623,16 +624,42 @@ static const struct iio_buffer_setup_ops fxls8962af_buffer_ops = {
.postdisable = fxls8962af_buffer_postdisable, .postdisable = fxls8962af_buffer_postdisable,
}; };
static int fxls8962af_i2c_raw_read_errata3(struct fxls8962af_data *data,
u16 *buffer, int samples,
int sample_length)
{
int i, ret;
for (i = 0; i < samples; i++) {
ret = regmap_raw_read(data->regmap, FXLS8962AF_BUF_X_LSB,
&buffer[i * 3], sample_length);
if (ret)
return ret;
}
return ret;
}
static int fxls8962af_fifo_transfer(struct fxls8962af_data *data, static int fxls8962af_fifo_transfer(struct fxls8962af_data *data,
u16 *buffer, int samples) u16 *buffer, int samples)
{ {
struct device *dev = regmap_get_device(data->regmap); struct device *dev = regmap_get_device(data->regmap);
int sample_length = 3 * sizeof(*buffer); int sample_length = 3 * sizeof(*buffer);
int ret;
int total_length = samples * sample_length; int total_length = samples * sample_length;
int ret;
if (i2c_verify_client(dev))
/*
* Due to errata bug:
* E3: FIFO burst read operation error using I2C interface
* We have to avoid burst reads on I2C..
*/
ret = fxls8962af_i2c_raw_read_errata3(data, buffer, samples,
sample_length);
else
ret = regmap_raw_read(data->regmap, FXLS8962AF_BUF_X_LSB, buffer,
total_length);
ret = regmap_raw_read(data->regmap, FXLS8962AF_BUF_X_LSB, buffer,
total_length);
if (ret) if (ret)
dev_err(dev, "Error transferring data from fifo: %d\n", ret); dev_err(dev, "Error transferring data from fifo: %d\n", ret);