iio: adis: Move burst mode into adis_data

Add burst mode variables in the per device specific data structure. As
some drivers support multiple devices with different burst sizes it
makes sense this data to be in `adis_data`. While moving the variables,
there are two main differences:

1. The `en`variable is dropped. If a device supports burst mode, it will
just use it as it will has better performance for almost all real use
cases.
2. Replace `extra_len` by `burst_len`. Users should now explicitly
define the length of the burst buffer as it is typically constant. This
also allows to remove the following line from the library:

```
/* All but the timestamp channel */
burst_length = (indio_dev->num_channels - 1) * sizeof(u16);
```

The library should not assume that a timestamp channel is defined.
Moreover, most parts also include some diagnostic data, crc, etc.. in
the burst buffer that needed to be included in an `extra_len` variable
which is not that nice. On top of this, some devices already start to
have some 32bit size channels ...

This patch is also a move to completely drop the `struct adis_burst`
from the library.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20200917155223.218500-2-nuno.sa@analog.com

diff --git a/drivers/iio/imu/adis_buffer.c b/drivers/iio/imu/adis_buffer.c
index df6144285470751218443933a67acbc3109557dd..ac354321f63a39635391958b79c10df57a37b81b 100644 (file)
--- a/drivers/iio/imu/adis_buffer.c
+++ b/drivers/iio/imu/adis_buffer.c
@@ -26,12 +26,10 @@ static int adis_update_scan_mode_burst(struct iio_dev *indio_dev,
        unsigned int burst_length, burst_max_length;
        u8 *tx;
 
-       /* All but the timestamp channel */
-       burst_length = (indio_dev->num_channels - 1) * sizeof(u16);
-       burst_length += adis->burst->extra_len + adis->burst_extra_len;
+       burst_length = adis->data->burst_len + adis->burst_extra_len;
 
-       if (adis->burst->burst_max_len)
-               burst_max_length = adis->burst->burst_max_len;
+       if (adis->data->burst_max_len)
+               burst_max_length = adis->data->burst_max_len;
        else
                burst_max_length = burst_length;
 
@@ -47,7 +45,7 @@ static int adis_update_scan_mode_burst(struct iio_dev *indio_dev,
        }
 
        tx = adis->buffer + burst_max_length;
-       tx[0] = ADIS_READ_REG(adis->burst->reg_cmd);
+       tx[0] = ADIS_READ_REG(adis->data->burst_reg_cmd);
        tx[1] = 0;
 
        adis->xfer[0].tx_buf = tx;
@@ -76,7 +74,7 @@ int adis_update_scan_mode(struct iio_dev *indio_dev,
        kfree(adis->xfer);
        kfree(adis->buffer);
 
-       if (adis->burst && adis->burst->en)
+       if (adis->data->burst_len)
                return adis_update_scan_mode_burst(indio_dev, scan_mask);
 
        scan_count = indio_dev->scan_bytes / 2;

diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
index 01ba691da2f3218987a1b0450e5076aa888ef9aa..c502ea3b919931f08d6a1c3ea7d9bc21763e3956 100644 (file)
--- a/include/linux/iio/imu/adis.h
+++ b/include/linux/iio/imu/adis.h
@@ -51,6 +51,11 @@ struct adis_timeout {
  * @timeouts: Chip specific delays
  * @enable_irq: Hook for ADIS devices that have a special IRQ enable/disable
  * @has_paging: True if ADIS device has paged registers
+ * @burst_reg_cmd:     Register command that triggers burst
+ * @burst_len:         Burst size in the SPI RX buffer. If @burst_max_len is defined,
+ *                     this should be the minimum size supported by the device.
+ * @burst_max_len:     Holds the maximum burst size when the device supports
+ *                     more than one burst mode with different sizes
  */
 struct adis_data {
        unsigned int read_delay;
@@ -75,6 +80,10 @@ struct adis_data {
        int (*enable_irq)(struct adis *adis, bool enable);
 
        bool has_paging;
+
+       unsigned int burst_reg_cmd;
+       unsigned int burst_len;
+       unsigned int burst_max_len;
 };
 
 /**