Complexity here is that we have to break the transers after every word
so that the chip select can go high.
Note this is NOT a burst read, but rather a interleaved
register read - there may well be better ways of doing this.
The burst read supported by for example the adis16400 is too odd
to fit well into regmap.
---
drivers/base/regmap/regmap-spi-adi.c | 31 ++++++++++++++++++++++++++-----
1 files changed, 26 insertions(+), 5 deletions(-)
diff --git a/drivers/base/regmap/regmap-spi-adi.c b/drivers/base/regmap/regmap-spi-adi.c
index d4301cc..6b581fa 100644
--- a/drivers/base/regmap/regmap-spi-adi.c
+++ b/drivers/base/regmap/regmap-spi-adi.c
@@ -23,7 +23,7 @@ static int regmap_spi_write(struct device *dev, const void *data, size_t count)
int ret;
u8 *rawdata = (u8 *)data;
- BUG_ON(count != 3);
+// BUG_ON(count != 3);
/* Fiddling needed as the value is bigendian */
rawdata[0] = (rawdata[0] << 1) + 1;
ret = spi_write(spi, data, 2);
@@ -39,13 +39,34 @@ static int regmap_spi_read(struct device *dev,
void *val, size_t val_size)
{
struct spi_device *spi = to_spi_device(dev);
- u8 *regraw = (u8 *)reg;
+ struct spi_transfer *xfers;
+ struct spi_message msg;
+ int i, ret;
+ u8 startreg = ((u8 *)reg)[0] << 1;
- regraw[0] <<= 1;
+ /* Could keep a single register read special version */
+ xfers = kzalloc(sizeof(*xfers)*((val_size >> 1) + 1), GFP_KERNEL);
+ if (xfers == NULL)
+ return -ENOMEM;
+
+ for (i = 0; i < val_size >> 1; i++) {
+ xfers[i].tx_buf = (u16 *)val + i;
+ ((u8 *)val)[i*2] = startreg + 2*i;
+ ((u8 *)val)[i*2 + 1] = 0;
+ xfers[i + 1].rx_buf = (u16 *)val + i;
+ xfers[i].bits_per_word = 8;
+ xfers[i].len = 2;
+ }
+ xfers[i].bits_per_word = 8;
+ xfers[i].len = 2;
+ spi_message_init(&msg);
+ for (i = 0; i < (val_size >> 1) + 1; i++)
+ spi_message_add_tail(&xfers[i], &msg);
- BUG_ON(reg_size != 1 || val_size != 2);
+ ret = spi_sync(spi, &msg);
+ kfree(xfers);
- return spi_write_then_read(spi, reg, 2, val, val_size);
+ return ret;
}
static struct regmap_bus regmap_spi_adi = {
--
1.7.3.4
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
