diff options
Diffstat (limited to 'driver/led/lm3630a.c')
| -rw-r--r-- | driver/led/lm3630a.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/driver/led/lm3630a.c b/driver/led/lm3630a.c index b65294c543..8eb12bb8d3 100644 --- a/driver/led/lm3630a.c +++ b/driver/led/lm3630a.c @@ -5,6 +5,7 @@ * TI LM3630A LED driver. */ +#include "hooks.h" #include "i2c.h" #include "lm3630a.h" #include "timer.h" @@ -23,6 +24,17 @@ static inline int lm3630a_read(uint8_t reg, int *val) return i2c_read8(I2C_PORT_KBLIGHT, LM3630A_I2C_ADDR, reg, val); } +static void deferred_lm3630a_poweron(void) +{ + /* + * Set full brightness so that PWM will control. This needs to happen + * after setting the control register, because enabling the banks + * resets the value to 0. + */ + lm3630a_write(LM3630A_REG_A_BRIGHTNESS, 0xff); +} +DECLARE_DEFERRED(deferred_lm3630a_poweron); + int lm3630a_poweron(void) { int ret = 0; @@ -51,13 +63,11 @@ int lm3630a_poweron(void) LM3630A_CTRL_BIT_LED2_ON_A); /* - * Set full brightness so that PWM will control. This needs to happen - * after setting the control register, because enabling the banks - * resets the value to 0 (the short sleep prevents a race between the - * chip resetting the value to 0 and our command). + * Only set the brightness after ~100 ms. Without this, LED may blink + * for a short duration, as the PWM sampler sometimes appears to be + * confused, and slowly dim from a large initial PWM input value. */ - usleep(100); - ret |= lm3630a_write(LM3630A_REG_A_BRIGHTNESS, 0xff); + hook_call_deferred(&deferred_lm3630a_poweron_data, 100 * MSEC); return ret; } |