[PATCH 4.4 46/47] iio: accel: bma180: Fix BMA25x bandwidth register values

Greg Kroah-Hartman
2021-07-26T15:42:25Z

From: Stephan Gerhold <stephan@gerhold.net>

commit 8090d67421ddab0ae932abab5a60200598bf0bbb upstream

According to the BMA253 datasheet [1] and BMA250 datasheet [2] the
bandwidth value for BMA25x should be set as 01xxx:

"Settings 00xxx result in a bandwidth of 7.81 Hz; [...]
It is recommended [...] to use the range from ´01000b´ to ´01111b´
only in order to be compatible with future products."

However, at the moment the drivers sets bandwidth values from 0 to 6,
which is not recommended and always results into 7.81 Hz bandwidth
according to the datasheet.

Fix this by introducing a bw_offset = 8 = 01000b for BMA25x,
so the additional bit is always set for BMA25x.

[1]: https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bma253-ds000.pdf
[2]: https://datasheet.octopart.com/BMA250-Bosch-datasheet-15540103.pdf

Cc: Peter Meerwald <pmeerw@pmeerw.net>
Fixes: 2017cff24cc0 ("iio:bma180: Add BMA250 chip support")
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210526094408.34298-2-stephan@gerhold.net
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/iio/accel/bma180.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/iio/accel/bma180.c
+++ b/drivers/iio/accel/bma180.c
@@ -49,7 +49,7 @@ struct bma180_part_info {

u8 int_reset_reg, int_reset_mask;
u8 sleep_reg, sleep_mask;
- u8 bw_reg, bw_mask;
+ u8 bw_reg, bw_mask, bw_offset;
u8 scale_reg, scale_mask;
u8 power_reg, power_mask, lowpower_val;
u8 int_enable_reg, int_enable_mask;
@@ -105,6 +105,7 @@ struct bma180_part_info {

#define BMA250_RANGE_MASK GENMASK(3, 0) /* Range of accel values */
#define BMA250_BW_MASK GENMASK(4, 0) /* Accel bandwidth */
+#define BMA250_BW_OFFSET 8
#define BMA250_SUSPEND_MASK BIT(7) /* chip will sleep */
#define BMA250_LOWPOWER_MASK BIT(6)
#define BMA250_DATA_INTEN_MASK BIT(4)
@@ -242,7 +243,8 @@ static int bma180_set_bw(struct bma180_d
for (i = 0; i < data->part_info->num_bw; ++i) {
if (data->part_info->bw_table[i] == val) {
ret = bma180_set_bits(data, data->part_info->bw_reg,
- data->part_info->bw_mask, i);
+ data->part_info->bw_mask,
+ i + data->part_info->bw_offset);
if (ret) {
dev_err(&data->client->dev,
"failed to set bandwidth\n");
@@ -660,6 +662,7 @@ static const struct bma180_part_info bma
.sleep_mask = BMA250_SUSPEND_MASK,
.bw_reg = BMA250_BW_REG,
.bw_mask = BMA250_BW_MASK,
+ .bw_offset = BMA250_BW_OFFSET,
.scale_reg = BMA250_RANGE_REG,
.scale_mask = BMA250_RANGE_MASK,
.power_reg = BMA250_POWER_REG,