| Message ID | ZFEzmA/0whRO6IFv@fedora (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | iio: bu27034: Ensure reset is written | expand |
On 5/2/23 19:00, Matti Vaittinen wrote: > The reset bit must be always written to the hardware no matter what value > is in a cache or register. Ensure this by using regmap_write_bits() > instead of the regmap_update_bits(). Furthermore, the RESET bit may be > self-clearing, so mark the SYSTEM_CONTROL register volatile to guarantee > we do also read the right state - should we ever need to read it. > > Signed-off by: Matti Vaittinen <mazziesaccount@gmail.com> I misspelled the Signed-off-by. Sorry folks. I'll re-spin. Yours, -- Matti
diff --git a/drivers/iio/light/rohm-bu27034.c b/drivers/iio/light/rohm-bu27034.c index 25c9b79574a5..740ebd86b6e5 100644 --- a/drivers/iio/light/rohm-bu27034.c +++ b/drivers/iio/light/rohm-bu27034.c @@ -231,6 +231,9 @@ struct bu27034_result { static const struct regmap_range bu27034_volatile_ranges[] = { { + .range_min = BU27034_REG_SYSTEM_CONTROL, + .range_max = BU27034_REG_SYSTEM_CONTROL, + }, { .range_min = BU27034_REG_MODE_CONTROL4, .range_max = BU27034_REG_MODE_CONTROL4, }, { @@ -1272,7 +1275,7 @@ static int bu27034_chip_init(struct bu27034_data *data) int ret, sel; /* Reset */ - ret = regmap_update_bits(data->regmap, BU27034_REG_SYSTEM_CONTROL, + ret = regmap_write_bits(data->regmap, BU27034_REG_SYSTEM_CONTROL, BU27034_MASK_SW_RESET, BU27034_MASK_SW_RESET); if (ret) return dev_err_probe(data->dev, ret, "Sensor reset failed\n");
The reset bit must be always written to the hardware no matter what value is in a cache or register. Ensure this by using regmap_write_bits() instead of the regmap_update_bits(). Furthermore, the RESET bit may be self-clearing, so mark the SYSTEM_CONTROL register volatile to guarantee we do also read the right state - should we ever need to read it. Signed-off by: Matti Vaittinen <mazziesaccount@gmail.com> Fixes: e52afbd61039 ("iio: light: ROHM BU27034 Ambient Light Sensor") --- I haven't verified if the reset bit is self-clearin as I did temporarily give away the HW. In worst case the bit is not self clearing - but we don't really get performance penalty even if we set the register volatile because the SYSTEM_CONTROL register only has the part-ID and the reset fields. The part-ID is only read once at probe. --- drivers/iio/light/rohm-bu27034.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) base-commit: 7fcbd72176076c44b47e8f68f0223c02c411f420