diff options
| -rw-r--r-- | drivers/iio/light/gp2ap002.c | 92 |
1 files changed, 14 insertions, 78 deletions
diff --git a/drivers/iio/light/gp2ap002.c b/drivers/iio/light/gp2ap002.c index 433907619268..b7ef16b28280 100644 --- a/drivers/iio/light/gp2ap002.c +++ b/drivers/iio/light/gp2ap002.c @@ -205,71 +205,27 @@ err_retrig: return IRQ_HANDLED; } -struct gp2ap002_illuminance { - unsigned int curr; - unsigned int lux; -}; - /* * This array maps current and lux. * * Ambient light sensing range is 3 to 55000 lux. * * This mapping is based on the following formula. - * illuminance = 10 ^ (current / 10) + * illuminance = 10 ^ (current[mA] / 10) + * + * When the ADC measures 0, return 0 lux. */ -static const struct gp2ap002_illuminance gp2ap002_illuminance_table[] = { - { .curr = 5, .lux = 3 }, - { .curr = 6, .lux = 4 }, - { .curr = 7, .lux = 5 }, - { .curr = 8, .lux = 6 }, - { .curr = 9, .lux = 8 }, - { .curr = 10, .lux = 10 }, - { .curr = 11, .lux = 12 }, - { .curr = 12, .lux = 16 }, - { .curr = 13, .lux = 20 }, - { .curr = 14, .lux = 25 }, - { .curr = 15, .lux = 32 }, - { .curr = 16, .lux = 40 }, - { .curr = 17, .lux = 50 }, - { .curr = 18, .lux = 63 }, - { .curr = 19, .lux = 79 }, - { .curr = 20, .lux = 100 }, - { .curr = 21, .lux = 126 }, - { .curr = 22, .lux = 158 }, - { .curr = 23, .lux = 200 }, - { .curr = 24, .lux = 251 }, - { .curr = 25, .lux = 316 }, - { .curr = 26, .lux = 398 }, - { .curr = 27, .lux = 501 }, - { .curr = 28, .lux = 631 }, - { .curr = 29, .lux = 794 }, - { .curr = 30, .lux = 1000 }, - { .curr = 31, .lux = 1259 }, - { .curr = 32, .lux = 1585 }, - { .curr = 33, .lux = 1995 }, - { .curr = 34, .lux = 2512 }, - { .curr = 35, .lux = 3162 }, - { .curr = 36, .lux = 3981 }, - { .curr = 37, .lux = 5012 }, - { .curr = 38, .lux = 6310 }, - { .curr = 39, .lux = 7943 }, - { .curr = 40, .lux = 10000 }, - { .curr = 41, .lux = 12589 }, - { .curr = 42, .lux = 15849 }, - { .curr = 43, .lux = 19953 }, - { .curr = 44, .lux = 25119 }, - { .curr = 45, .lux = 31623 }, - { .curr = 46, .lux = 39811 }, - { .curr = 47, .lux = 50119 }, +static const u16 gp2ap002_illuminance_table[] = { + 0, 1, 1, 2, 2, 3, 4, 5, 6, 8, 10, 12, 16, 20, 25, 32, 40, 50, 63, 79, + 100, 126, 158, 200, 251, 316, 398, 501, 631, 794, 1000, 1259, 1585, + 1995, 2512, 3162, 3981, 5012, 6310, 7943, 10000, 12589, 15849, 19953, + 25119, 31623, 39811, 50119, }; static int gp2ap002_get_lux(struct gp2ap002 *gp2ap002) { - const struct gp2ap002_illuminance *ill1; - const struct gp2ap002_illuminance *ill2; int ret, res; - int i; + u16 lux; ret = iio_read_channel_processed(gp2ap002->alsout, &res); if (ret < 0) @@ -277,31 +233,11 @@ static int gp2ap002_get_lux(struct gp2ap002 *gp2ap002) dev_dbg(gp2ap002->dev, "read %d mA from ADC\n", res); - ill1 = &gp2ap002_illuminance_table[0]; - if (res < ill1->curr) { - dev_dbg(gp2ap002->dev, "total darkness\n"); - return 0; - } - for (i = 0; i < ARRAY_SIZE(gp2ap002_illuminance_table) - 1; i++) { - ill1 = &gp2ap002_illuminance_table[i]; - ill2 = &gp2ap002_illuminance_table[i + 1]; - - if (res > ill2->curr) - continue; - if ((res <= ill1->curr) && (res >= ill2->curr)) - break; - } - if (res > ill2->curr) { - dev_info_once(gp2ap002->dev, "max current overflow\n"); - return ill2->curr; - } - /* Interpolate and return */ - dev_dbg(gp2ap002->dev, "interpolate index %d and %d\n", i, i + 1); - /* How many steps along the curve */ - i = res - ill1->curr; /* x - x0 */ - /* Linear interpolation */ - return ill1->lux + i * - ((ill2->lux - ill1->lux) / (ill2->curr - ill1->curr)); + /* ensure we don't under/overflow */ + res = clamp(res, 0, (int)ARRAY_SIZE(gp2ap002_illuminance_table) - 1); + lux = gp2ap002_illuminance_table[res]; + + return (int)lux; } static int gp2ap002_read_raw(struct iio_dev *indio_dev, |