diff options
Diffstat (limited to 'driver/als_isl29035.c')
| -rw-r--r-- | driver/als_isl29035.c | 31 |
1 files changed, 19 insertions, 12 deletions
diff --git a/driver/als_isl29035.c b/driver/als_isl29035.c index 13e5d77c14..3eef3a170e 100644 --- a/driver/als_isl29035.c +++ b/driver/als_isl29035.c @@ -7,6 +7,7 @@ #include "driver/als_isl29035.h" #include "common.h" +#include "hooks.h" #include "i2c.h" #include "timer.h" @@ -22,22 +23,27 @@ #define ILS29035_REG_INT_HT_MSB 7 #define ILS29035_REG_ID 15 +static void isl29035_init(void) +{ + /* + * Tell it to read continually. This uses 70uA, as opposed to nearly + * zero, but it makes the hook/update code cleaner (we don't want to + * wait 90ms to read on demand while processing hook callbacks). + */ + (void)i2c_write8(I2C_PORT_ALS, ILS29035_I2C_ADDR, + ILS29035_REG_COMMAND_I, 0xa0); +} +DECLARE_HOOK(HOOK_CHIPSET_RESUME, isl29035_init, HOOK_PRIO_DEFAULT); + int isl29035_read_lux(int *lux) { int rv, lsb, msb, data; - /* Tell it to read once */ - rv = i2c_write8(I2C_PORT_ALS, ILS29035_I2C_ADDR, - ILS29035_REG_COMMAND_I, 0x20); - if (rv) - return rv; - - /* The highest precision (default) should take ~90ms */ - usleep(100 * MSEC); - - /* NOTE: It is necessary to read the LSB first, then the MSB. If you do + /* + * NOTE: It is necessary to read the LSB first, then the MSB. If you do * it in the opposite order, the results are not correct. This is - * apparently an undocumented "feature". + * apparently an undocumented "feature". It's especially noticeable in + * one-shot mode. */ /* Read lsb */ @@ -57,7 +63,8 @@ int isl29035_read_lux(int *lux) /* * The default power-on values will give 16 bits of precision: * 0x0000-0xffff indicates 0-1000 lux. If you change the defaults, - * you'll need to change the scale factor accordingly. + * you'll need to change the scale factor accordingly (and maybe this + * expression, to avoid rounding errors). */ *lux = data * 1000 / 0xffff; |