[PATCH 1/2] bu27034: ROHM BU27034NUC to BU27034ANUC

From: Matti Vaittinen
Date: Mon Jun 10 2024 - 06:01:43 EST

The ROHM BU27034NUC was cancelled and BU27034ANUC is replacing this
sensor. Use the BU27034NUC driver to support the new BU27034ANUC.

According to ROHM, the BU27034NUC was never mass-produced. Hence dropping
the BU27034NUC support and using this driver to support BU27034ANUC
should not be a problem to users.

Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
Fixes: e52afbd61039 ("iio: light: ROHM BU27034 Ambient Light Sensor")
---
drivers/iio/light/rohm-bu27034.c | 321 +++++++------------------------
1 file changed, 68 insertions(+), 253 deletions(-)

diff --git a/drivers/iio/light/rohm-bu27034.c b/drivers/iio/light/rohm-bu27034.c
index bf3de853a811..51acad2cafbd 100644
--- a/drivers/iio/light/rohm-bu27034.c
+++ b/drivers/iio/light/rohm-bu27034.c
@@ -1,9 +1,8 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * BU27034 ROHM Ambient Light Sensor
+ * BU27034ANUC ROHM Ambient Light Sensor
*
* Copyright (c) 2023, ROHM Semiconductor.
- * https://fscdn.rohm.com/en/products/databook/datasheet/ic/sensor/light/bu27034nuc-e.pdf
*/

#include <linux/bitfield.h>
@@ -30,17 +29,15 @@

#define BU27034_REG_MODE_CONTROL2 0x42
#define BU27034_MASK_D01_GAIN GENMASK(7, 3)
-#define BU27034_MASK_D2_GAIN_HI GENMASK(7, 6)
-#define BU27034_MASK_D2_GAIN_LO GENMASK(2, 0)

#define BU27034_REG_MODE_CONTROL3 0x43
#define BU27034_REG_MODE_CONTROL4 0x44
#define BU27034_MASK_MEAS_EN BIT(0)
#define BU27034_MASK_VALID BIT(7)
+#define BU27034_NUM_HW_DATA_CHANS 2
#define BU27034_REG_DATA0_LO 0x50
#define BU27034_REG_DATA1_LO 0x52
-#define BU27034_REG_DATA2_LO 0x54
-#define BU27034_REG_DATA2_HI 0x55
+#define BU27034_REG_DATA1_HI 0x53
#define BU27034_REG_MANUFACTURER_ID 0x92
#define BU27034_REG_MAX BU27034_REG_MANUFACTURER_ID

@@ -88,58 +85,48 @@ enum {
BU27034_CHAN_ALS,
BU27034_CHAN_DATA0,
BU27034_CHAN_DATA1,
- BU27034_CHAN_DATA2,
BU27034_NUM_CHANS
};

static const unsigned long bu27034_scan_masks[] = {
- GENMASK(BU27034_CHAN_DATA2, BU27034_CHAN_ALS), 0
+ GENMASK(BU27034_CHAN_DATA1, BU27034_CHAN_DATA0),
+ GENMASK(BU27034_CHAN_DATA1, BU27034_CHAN_ALS), 0
};

/*
- * Available scales with gain 1x - 4096x, timings 55, 100, 200, 400 mS
+ * Available scales with gain 1x - 1024x, timings 55, 100, 200, 400 mS
* Time impacts to gain: 1x, 2x, 4x, 8x.
*
- * => Max total gain is HWGAIN * gain by integration time (8 * 4096) = 32768
+ * => Max total gain is HWGAIN * gain by integration time (8 * 1024) = 8192
+ * if 1x gain is scale 1, scale for 2x gain is 0.5, 4x => 0.25,
+ * ... 8192x => 0.0001220703125 => 122070.3125 nanos
*
- * Using NANO precision for scale we must use scale 64x corresponding gain 1x
- * to avoid precision loss. (32x would result scale 976 562.5(nanos).
+ * Using NANO precision for scale, we must use scale 16x corresponding gain 1x
+ * to avoid precision loss. (8x would result scale 976 562.5(nanos).
*/
-#define BU27034_SCALE_1X 64
+#define BU27034_SCALE_1X 16

/* See the data sheet for the "Gain Setting" table */
#define BU27034_GSEL_1X 0x00 /* 00000 */
#define BU27034_GSEL_4X 0x08 /* 01000 */
-#define BU27034_GSEL_16X 0x0a /* 01010 */
#define BU27034_GSEL_32X 0x0b /* 01011 */
-#define BU27034_GSEL_64X 0x0c /* 01100 */
#define BU27034_GSEL_256X 0x18 /* 11000 */
#define BU27034_GSEL_512X 0x19 /* 11001 */
#define BU27034_GSEL_1024X 0x1a /* 11010 */
-#define BU27034_GSEL_2048X 0x1b /* 11011 */
-#define BU27034_GSEL_4096X 0x1c /* 11100 */

/* Available gain settings */
static const struct iio_gain_sel_pair bu27034_gains[] = {
GAIN_SCALE_GAIN(1, BU27034_GSEL_1X),
GAIN_SCALE_GAIN(4, BU27034_GSEL_4X),
- GAIN_SCALE_GAIN(16, BU27034_GSEL_16X),
GAIN_SCALE_GAIN(32, BU27034_GSEL_32X),
- GAIN_SCALE_GAIN(64, BU27034_GSEL_64X),
GAIN_SCALE_GAIN(256, BU27034_GSEL_256X),
GAIN_SCALE_GAIN(512, BU27034_GSEL_512X),
GAIN_SCALE_GAIN(1024, BU27034_GSEL_1024X),
- GAIN_SCALE_GAIN(2048, BU27034_GSEL_2048X),
- GAIN_SCALE_GAIN(4096, BU27034_GSEL_4096X),
};

/*
- * The IC has 5 modes for sampling time. 5 mS mode is exceptional as it limits
- * the data collection to data0-channel only and cuts the supported range to
- * 10 bit. It is not supported by the driver.
- *
- * "normal" modes are 55, 100, 200 and 400 mS modes - which do have direct
- * multiplying impact to the register values (similar to gain).
+ * Measurement modes are 55, 100, 200 and 400 mS modes - which do have direct
+ * multiplying impact to the data register values (similar to gain).
*
* This means that if meas-mode is changed for example from 400 => 200,
* the scale is doubled. Eg, time impact to total gain is x1, x2, x4, x8.
@@ -156,11 +143,11 @@ static const struct iio_itime_sel_mul bu27034_itimes[] = {
GAIN_SCALE_ITIME_US(55000, BU27034_MEAS_MODE_55MS, 1),
};

-#define BU27034_CHAN_DATA(_name, _ch2) \
+#define BU27034_CHAN_DATA(_name) \
{ \
.type = IIO_INTENSITY, \
.channel = BU27034_CHAN_##_name, \
- .channel2 = (_ch2), \
+ .channel2 = IIO_MOD_LIGHT_CLEAR, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
BIT(IIO_CHAN_INFO_SCALE), \
.info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE), \
@@ -195,13 +182,12 @@ static const struct iio_chan_spec bu27034_channels[] = {
/*
* The BU27034 DATA0 and DATA1 channels are both on the visible light
* area (mostly). The data0 sensitivity peaks at 500nm, DATA1 at 600nm.
- * These wave lengths are pretty much on the border of colours making
- * these a poor candidates for R/G/B standardization. Hence they're both
- * marked as clear channels
+ * These wave lengths are cyan(ish) and orange(ish), making these
+ * sub-optiomal candidates for R/G/B standardization. Hence they're
+ * both marked as clear channels.
*/
- BU27034_CHAN_DATA(DATA0, IIO_MOD_LIGHT_CLEAR),
- BU27034_CHAN_DATA(DATA1, IIO_MOD_LIGHT_CLEAR),
- BU27034_CHAN_DATA(DATA2, IIO_MOD_LIGHT_IR),
+ BU27034_CHAN_DATA(DATA0),
+ BU27034_CHAN_DATA(DATA1),
IIO_CHAN_SOFT_TIMESTAMP(4),
};

@@ -215,20 +201,14 @@ struct bu27034_data {
struct mutex mutex;
struct iio_gts gts;
struct task_struct *task;
- __le16 raw[3];
+ __le16 raw[BU27034_NUM_HW_DATA_CHANS];
struct {
u32 mlux;
- __le16 channels[3];
+ __le16 channels[BU27034_NUM_HW_DATA_CHANS];
s64 ts __aligned(8);
} scan;
};

-struct bu27034_result {
- u16 ch0;
- u16 ch1;
- u16 ch2;
-};
-
static const struct regmap_range bu27034_volatile_ranges[] = {
{
.range_min = BU27034_REG_SYSTEM_CONTROL,
@@ -238,7 +218,7 @@ static const struct regmap_range bu27034_volatile_ranges[] = {
.range_max = BU27034_REG_MODE_CONTROL4,
}, {
.range_min = BU27034_REG_DATA0_LO,
- .range_max = BU27034_REG_DATA2_HI,
+ .range_max = BU27034_REG_DATA1_HI,
},
};

@@ -250,7 +230,7 @@ static const struct regmap_access_table bu27034_volatile_regs = {
static const struct regmap_range bu27034_read_only_ranges[] = {
{
.range_min = BU27034_REG_DATA0_LO,
- .range_max = BU27034_REG_DATA2_HI,
+ .range_max = BU27034_REG_DATA1_HI,
}, {
.range_min = BU27034_REG_MANUFACTURER_ID,
.range_max = BU27034_REG_MANUFACTURER_ID,
@@ -281,39 +261,15 @@ static int bu27034_get_gain_sel(struct bu27034_data *data, int chan)
{
int ret, val;

- switch (chan) {
- case BU27034_CHAN_DATA0:
- case BU27034_CHAN_DATA1:
- {
- int reg[] = {
- [BU27034_CHAN_DATA0] = BU27034_REG_MODE_CONTROL2,
- [BU27034_CHAN_DATA1] = BU27034_REG_MODE_CONTROL3,
- };
- ret = regmap_read(data->regmap, reg[chan], &val);
- if (ret)
- return ret;
-
- return FIELD_GET(BU27034_MASK_D01_GAIN, val);
- }
- case BU27034_CHAN_DATA2:
- {
- int d2_lo_bits = fls(BU27034_MASK_D2_GAIN_LO);
-
- ret = regmap_read(data->regmap, BU27034_REG_MODE_CONTROL2, &val);
- if (ret)
- return ret;
+ int reg[] = {
+ [BU27034_CHAN_DATA0] = BU27034_REG_MODE_CONTROL2,
+ [BU27034_CHAN_DATA1] = BU27034_REG_MODE_CONTROL3,
+ };
+ ret = regmap_read(data->regmap, reg[chan], &val);
+ if (ret)
+ return ret;

- /*
- * The data2 channel gain is composed by 5 non continuous bits
- * [7:6], [2:0]. Thus when we combine the 5-bit 'selector'
- * from register value we must right shift the high bits by 3.
- */
- return FIELD_GET(BU27034_MASK_D2_GAIN_HI, val) << d2_lo_bits |
- FIELD_GET(BU27034_MASK_D2_GAIN_LO, val);
- }
- default:
- return -EINVAL;
- }
+ return FIELD_GET(BU27034_MASK_D01_GAIN, val);
}

static int bu27034_get_gain(struct bu27034_data *data, int chan, int *gain)
@@ -396,44 +352,9 @@ static int bu27034_write_gain_sel(struct bu27034_data *data, int chan, int sel)
};
int mask, val;

- if (chan != BU27034_CHAN_DATA0 && chan != BU27034_CHAN_DATA1)
- return -EINVAL;
-
val = FIELD_PREP(BU27034_MASK_D01_GAIN, sel);
-
mask = BU27034_MASK_D01_GAIN;

- if (chan == BU27034_CHAN_DATA0) {
- /*
- * We keep the same gain for channel 2 as we set for channel 0
- * We can't allow them to be individually controlled because
- * setting one will impact also the other. Also, if we don't
- * always update both gains we may result unsupported bit
- * combinations.
- *
- * This is not nice but this is yet another place where the
- * user space must be prepared to surprizes. Namely, see chan 2
- * gain changed when chan 0 gain is changed.
- *
- * This is not fatal for most users though. I don't expect the
- * channel 2 to be used in any generic cases - the intensity
- * values provided by the sensor for IR area are not openly
- * documented. Also, channel 2 is not used for visible light.
- *
- * So, if there is application which is written to utilize the
- * channel 2 - then it is probably specifically targeted to this
- * sensor and knows how to utilize those values. It is safe to
- * hope such user can also cope with the gain changes.
- */
- mask |= BU27034_MASK_D2_GAIN_LO;
-
- /*
- * The D2 gain bits are directly the lowest bits of selector.
- * Just do add those bits to the value
- */
- val |= sel & BU27034_MASK_D2_GAIN_LO;
- }
-
return regmap_update_bits(data->regmap, reg[chan], mask, val);
}

@@ -441,13 +362,6 @@ static int bu27034_set_gain(struct bu27034_data *data, int chan, int gain)
{
int ret;

- /*
- * We don't allow setting channel 2 gain as it messes up the
- * gain for channel 0 - which shares the high bits
- */
- if (chan != BU27034_CHAN_DATA0 && chan != BU27034_CHAN_DATA1)
- return -EINVAL;
-
ret = iio_gts_find_sel_by_gain(&data->gts, gain);
if (ret < 0)
return ret;
@@ -571,9 +485,6 @@ static int bu27034_set_scale(struct bu27034_data *data, int chan,
int ret, time_sel, gain_sel, i;
bool found = false;

- if (chan == BU27034_CHAN_DATA2)
- return -EINVAL;
-
if (chan == BU27034_CHAN_ALS) {
if (val == 0 && val2 == 1000000)
return 0;
@@ -598,9 +509,7 @@ static int bu27034_set_scale(struct bu27034_data *data, int chan,

/*
* Populate information for the other channel which should also
- * maintain the scale. (Due to the HW limitations the chan2
- * gets the same gain as chan0, so we only need to explicitly
- * set the chan 0 and 1).
+ * maintain the scale.
*/
if (chan == BU27034_CHAN_DATA0)
gain.chan = BU27034_CHAN_DATA1;
@@ -614,7 +523,7 @@ static int bu27034_set_scale(struct bu27034_data *data, int chan,
/*
* Iterate through all the times to see if we find one which
* can support requested scale for requested channel, while
- * maintaining the scale for other channels
+ * maintaining the scale for the other channel
*/
for (i = 0; i < data->gts.num_itime; i++) {
new_time_sel = data->gts.itime_table[i].sel;
@@ -629,7 +538,7 @@ static int bu27034_set_scale(struct bu27034_data *data, int chan,
if (ret)
continue;

- /* Can the other channel(s) maintain scale? */
+ /* Can the other channel maintain scale? */
ret = iio_gts_find_new_gain_sel_by_old_gain_time(
&data->gts, gain.old_gain, time_sel,
new_time_sel, &gain.new_gain);
@@ -641,7 +550,7 @@ static int bu27034_set_scale(struct bu27034_data *data, int chan,
}
if (!found) {
dev_dbg(data->dev,
- "Can't set scale maintaining other channels\n");
+ "Can't set scale maintaining other channel\n");
ret = -EINVAL;

goto unlock_out;
@@ -665,102 +574,21 @@ static int bu27034_set_scale(struct bu27034_data *data, int chan,
}

/*
- * for (D1/D0 < 0.87):
- * lx = 0.004521097 * D1 - 0.002663996 * D0 +
- * 0.00012213 * D1 * D1 / D0
- *
- * => 115.7400832 * ch1 / gain1 / mt -
- * 68.1982976 * ch0 / gain0 / mt +
- * 0.00012213 * 25600 * (ch1 / gain1 / mt) * 25600 *
- * (ch1 /gain1 / mt) / (25600 * ch0 / gain0 / mt)
+ * for (D1/D0 < 1.5):
+ * lx = (0.001193 * D0 + (-0.0000747) * D1) * ((D1/D0 – 1.5) * (0.25) + 1)
*
- * A = 0.00012213 * 25600 * (ch1 /gain1 / mt) * 25600 *
- * (ch1 /gain1 / mt) / (25600 * ch0 / gain0 / mt)
- * => 0.00012213 * 25600 * (ch1 /gain1 / mt) *
- * (ch1 /gain1 / mt) / (ch0 / gain0 / mt)
- * => 0.00012213 * 25600 * (ch1 / gain1) * (ch1 /gain1 / mt) /
- * (ch0 / gain0)
- * => 0.00012213 * 25600 * (ch1 / gain1) * (ch1 /gain1 / mt) *
- * gain0 / ch0
- * => 3.126528 * ch1 * ch1 * gain0 / gain1 / gain1 / mt /ch0
+ * => -0.000745625 * D0 + 0.0002515625 * D1 + -0.000018675 * D1 * D1 / D0
*
- * lx = (115.7400832 * ch1 / gain1 - 68.1982976 * ch0 / gain0) /
- * mt + A
- * => (115.7400832 * ch1 / gain1 - 68.1982976 * ch0 / gain0) /
- * mt + 3.126528 * ch1 * ch1 * gain0 / gain1 / gain1 / mt /
- * ch0
+ * => (6.44 * ch1 / gain1 + 19.088 * ch0 / gain0 -
+ * 0.47808 * ch1 * ch1 * gain0 / gain1 / gain1 / ch0) /
+ * mt
*
- * => (115.7400832 * ch1 / gain1 - 68.1982976 * ch0 / gain0 +
- * 3.126528 * ch1 * ch1 * gain0 / gain1 / gain1 / ch0) /
- * mt
+ * Else
+ * lx = 0.001193 * D0 - 0.0000747 * D1
*
- * For (0.87 <= D1/D0 < 1.00)
- * lx = (0.001331* D0 + 0.0000354 * D1) * ((D1/D0 – 0.87) * (0.385) + 1)
- * => (0.001331 * 256 * 100 * ch0 / gain0 / mt + 0.0000354 * 256 *
- * 100 * ch1 / gain1 / mt) * ((D1/D0 - 0.87) * (0.385) + 1)
- * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
- * ((D1/D0 - 0.87) * (0.385) + 1)
- * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
- * (0.385 * D1/D0 - 0.66505)
- * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
- * (0.385 * 256 * 100 * ch1 / gain1 / mt / (256 * 100 * ch0 / gain0 / mt) - 0.66505)
- * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
- * (9856 * ch1 / gain1 / mt / (25600 * ch0 / gain0 / mt) + 0.66505)
- * => 13.118336 * ch1 / (gain1 * mt)
- * + 22.66064768 * ch0 / (gain0 * mt)
- * + 8931.90144 * ch1 * ch1 * gain0 /
- * (25600 * ch0 * gain1 * gain1 * mt)
- * + 0.602694912 * ch1 / (gain1 * mt)
- *
- * => [0.3489024 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1)
- * + 22.66064768 * ch0 / gain0
- * + 13.721030912 * ch1 / gain1
- * ] / mt
- *
- * For (D1/D0 >= 1.00)
- *
- * lx = (0.001331* D0 + 0.0000354 * D1) * ((D1/D0 – 2.0) * (-0.05) + 1)
- * => (0.001331* D0 + 0.0000354 * D1) * (-0.05D1/D0 + 1.1)
- * => (0.001331 * 256 * 100 * ch0 / gain0 / mt + 0.0000354 * 256 *
- * 100 * ch1 / gain1 / mt) * (-0.05D1/D0 + 1.1)
- * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
- * (-0.05 * 256 * 100 * ch1 / gain1 / mt / (256 * 100 * ch0 / gain0 / mt) + 1.1)
- * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
- * (-1280 * ch1 / (gain1 * mt * 25600 * ch0 / gain0 / mt) + 1.1)
- * => (34.0736 * ch0 * -1280 * ch1 * gain0 * mt /( gain0 * mt * gain1 * mt * 25600 * ch0)
- * + 34.0736 * 1.1 * ch0 / (gain0 * mt)
- * + 0.90624 * ch1 * -1280 * ch1 *gain0 * mt / (gain1 * mt *gain1 * mt * 25600 * ch0)
- * + 1.1 * 0.90624 * ch1 / (gain1 * mt)
- * => -43614.208 * ch1 / (gain1 * mt * 25600)
- * + 37.48096 ch0 / (gain0 * mt)
- * - 1159.9872 * ch1 * ch1 * gain0 / (gain1 * gain1 * mt * 25600 * ch0)
- * + 0.996864 ch1 / (gain1 * mt)
- * => [
- * - 0.045312 * ch1 * ch1 * gain0 / (gain1 * gain1 * ch0)
- * - 0.706816 * ch1 / gain1
- * + 37.48096 ch0 /gain0
- * ] * mt
- *
- *
- * So, the first case (D1/D0 < 0.87) can be computed to a form:
- *
- * lx = (3.126528 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1) +
- * 115.7400832 * ch1 / gain1 +
- * -68.1982976 * ch0 / gain0
- * / mt
- *
- * Second case (0.87 <= D1/D0 < 1.00) goes to form:
- *
- * => [0.3489024 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1) +
- * 13.721030912 * ch1 / gain1 +
- * 22.66064768 * ch0 / gain0
- * ] / mt
- *
- * Third case (D1/D0 >= 1.00) goes to form:
- * => [-0.045312 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1) +
- * -0.706816 * ch1 / gain1 +
- * 37.48096 ch0 /(gain0
- * ] / mt
+ * => (1.91232 * ch1 / gain1 + 30.5408 * ch0 / gain0 +
+ * [0 * ch1 * ch1 * gain0 / gain1 / gain1 / ch0] ) /
+ * mt
*
* This can be unified to format:
* lx = [
@@ -770,19 +598,14 @@ static int bu27034_set_scale(struct bu27034_data *data, int chan,
* ] / mt
*
* For case 1:
- * A = 3.126528,
- * B = 115.7400832
- * C = -68.1982976
+ * A = -0.47808,
+ * B = 6.44,
+ * C = 19.088
*
* For case 2:
- * A = 0.3489024
- * B = 13.721030912
- * C = 22.66064768
- *
- * For case 3:
- * A = -0.045312
- * B = -0.706816
- * C = 37.48096
+ * A = 0
+ * B = 1.91232
+ * C = 30.5408
*/

struct bu27034_lx_coeff {
@@ -887,21 +710,16 @@ static int bu27034_fixp_calc_lx(unsigned int ch0, unsigned int ch1,
{
static const struct bu27034_lx_coeff coeff[] = {
{
- .A = 31265280, /* 3.126528 */
- .B = 1157400832, /*115.7400832 */
- .C = 681982976, /* -68.1982976 */
- .is_neg = {false, false, true},
+ .A = 4780800, /* -0.47808 */
+ .B = 64400000, /*6.44 */
+ .C = 190880000, /* 19.088 */
+ .is_neg = {true, false, false},
}, {
- .A = 3489024, /* 0.3489024 */
- .B = 137210309, /* 13.721030912 */
- .C = 226606476, /* 22.66064768 */
+ .A = 0, /* 0 */
+ .B = 19123200, /* 1.91232 */
+ .C = 305408000, /* 30.5408 */
/* All terms positive */
- }, {
- .A = 453120, /* -0.045312 */
- .B = 7068160, /* -0.706816 */
- .C = 374809600, /* 37.48096 */
- .is_neg = {true, true, false},
- }
+ },
};
const struct bu27034_lx_coeff *c = &coeff[coeff_idx];
u64 res = 0, terms[3];
@@ -973,7 +791,6 @@ static int bu27034_read_result(struct bu27034_data *data, int chan, int *res)
int reg[] = {
[BU27034_CHAN_DATA0] = BU27034_REG_DATA0_LO,
[BU27034_CHAN_DATA1] = BU27034_REG_DATA1_LO,
- [BU27034_CHAN_DATA2] = BU27034_REG_DATA2_LO,
};
int valid, ret;
__le16 val;
@@ -1040,7 +857,7 @@ static int bu27034_get_single_result(struct bu27034_data *data, int chan,
{
int ret;

- if (chan < BU27034_CHAN_DATA0 || chan > BU27034_CHAN_DATA2)
+ if (chan < BU27034_CHAN_DATA0 || chan > BU27034_CHAN_DATA1)
return -EINVAL;

ret = bu27034_meas_set(data, true);
@@ -1065,12 +882,10 @@ static int bu27034_get_single_result(struct bu27034_data *data, int chan,
* D1 = data1/ch1_gain/meas_time_ms * 25600
*
* Then:
- * if (D1/D0 < 0.87)
- * lx = (0.001331 * D0 + 0.0000354 * D1) * ((D1 / D0 - 0.87) * 3.45 + 1)
- * else if (D1/D0 < 1)
- * lx = (0.001331 * D0 + 0.0000354 * D1) * ((D1 / D0 - 0.87) * 0.385 + 1)
- * else
- * lx = (0.001331 * D0 + 0.0000354 * D1) * ((D1 / D0 - 2) * -0.05 + 1)
+ * If (D1/D0 < 1.5)
+ * lx = (0.001193 * D0 + (-0.0000747) * D1) * ((D1/D0 – 1.5) * (0.25) + 1)
+ * Else
+ * lx = (0.001193* D0 + (-0.0000747) * D1)
*
* We use it here. Users who have for example some colored lens
* need to modify the calculation but I hope this gives a starting point for
@@ -1139,7 +954,7 @@ static int bu27034_calc_mlux(struct bu27034_data *data, __le16 *res, int *val)

static int bu27034_get_mlux(struct bu27034_data *data, int chan, int *val)
{
- __le16 res[3];
+ __le16 res[BU27034_NUM_HW_DATA_CHANS];
int ret;

ret = bu27034_meas_set(data, true);
--
2.45.1


--
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]

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