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Subject[PATCH 1/1] iio:proximity:sx9360: Fix hardware gain read/write
Date
Similar to the handling of read/write in commit 108e4d4de2b5
("iio:proximity:sx9324: Fix hardware gain read/write"), we thought
a patch might be needed here as well.

There are four possible gain values according to 'sx9360_gain_vals[]':

1, 2, 4, and 8

The values are off by one when writing and reading the register. The
bits should be set according to this equation:

ilog2(<gain>) + 1

so that a gain of 8 is 0x4 in the register field and a gain of 4 is 0x3
in the register field, etc. Note that a gain of 0 is reserved per the
datasheet. The default gain (SX9360_REG_PROX_CTRL0_GAIN_1) is also
wrong. It should be 0x1 << 3, i.e. 0x8, not 0x80 which is setting the
reserved bit 7.

Fix this all up to properly handle the hardware gain and return errors
for invalid settings.

Signed-off-by: Xiaohui Zhang <xiaohuizhang@ruc.edu.cn>
---
drivers/iio/proximity/sx9360.c | 26 +++++++++++++++++++++-----
1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/proximity/sx9360.c b/drivers/iio/proximity/sx9360.c
index 3ebb30c8a4f6..3dbcc9f584cf 100644
--- a/drivers/iio/proximity/sx9360.c
+++ b/drivers/iio/proximity/sx9360.c
@@ -64,7 +64,10 @@
#define SX9360_REG_PROX_CTRL0_PHR 0x40
#define SX9360_REG_PROX_CTRL0_PHM 0x41
#define SX9360_REG_PROX_CTRL0_GAIN_MASK GENMASK(5, 3)
-#define SX9360_REG_PROX_CTRL0_GAIN_1 0x80
+#define SX9324_REG_PROX_CTRL0_GAIN_SHIFT 3
+#define SX9324_REG_PROX_CTRL0_GAIN_RSVD 0x0
+#define SX9324_REG_PROX_CTRL0_GAIN_1 0x1
+#define SX9324_REG_PROX_CTRL0_GAIN_8 0x4
#define SX9360_REG_PROX_CTRL0_RAWFILT_MASK GENMASK(2, 0)
#define SX9360_REG_PROX_CTRL0_RAWFILT_1P50 0x01
#define SX9360_REG_PROX_CTRL1 0x42
@@ -288,7 +291,14 @@ static int sx9360_read_gain(struct sx_common_data *data,
if (ret)
return ret;

- *val = 1 << FIELD_GET(SX9360_REG_PROX_CTRL0_GAIN_MASK, regval);
+ regval = FIELD_GET(SX9360_REG_PROX_CTRL0_GAIN_MASK, regval);
+ if (regval)
+ regval--;
+ else if (regval == SX9360_REG_PROX_CTRL0_GAIN_RSVD ||
+ regval > SX9360_REG_PROX_CTRL0_GAIN_8)
+ return -EINVAL;
+
+ *val = 1 << regval;

return IIO_VAL_INT;
}
@@ -630,8 +640,12 @@ static int sx9360_write_gain(struct sx_common_data *data,
unsigned int gain, reg;
int ret;

- gain = ilog2(val);
reg = SX9360_REG_PROX_CTRL0_PHR + chan->channel;
+
+ gain = ilog2(val) + 1;
+ if (val <= 0 || gain > SX9360_REG_PROX_CTRL0_GAIN_8)
+ return -EINVAL;
+
gain = FIELD_PREP(SX9360_REG_PROX_CTRL0_GAIN_MASK, gain);

mutex_lock(&data->mutex);
@@ -681,9 +695,11 @@ static const struct sx_common_reg_default sx9360_default_regs[] = {
{ SX9360_REG_AFE_PARAM1_PHM, SX9360_REG_AFE_PARAM1_AGAIN_PHM_6PF |
SX9360_REG_AFE_PARAM1_FREQ_83_33HZ },

- { SX9360_REG_PROX_CTRL0_PHR, SX9360_REG_PROX_CTRL0_GAIN_1 |
+ { SX9360_REG_PROX_CTRL0_PHR,
+ SX9360_REG_PROX_CTRL0_GAIN_1 << SX9360_REG_PROX_CTRL0_GAIN_SHIFT |
SX9360_REG_PROX_CTRL0_RAWFILT_1P50 },
- { SX9360_REG_PROX_CTRL0_PHM, SX9360_REG_PROX_CTRL0_GAIN_1 |
+ { SX9360_REG_PROX_CTRL0_PHM,
+ SX9360_REG_PROX_CTRL0_GAIN_1 << SX9360_REG_PROX_CTRL0_GAIN_SHIFT |
SX9360_REG_PROX_CTRL0_RAWFILT_1P50 },
{ SX9360_REG_PROX_CTRL1, SX9360_REG_PROX_CTRL1_AVGNEG_THRESH_16K },
{ SX9360_REG_PROX_CTRL2, SX9360_REG_PROX_CTRL2_AVGDEB_2SAMPLES |
--
2.17.1
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