diff options
Diffstat (limited to 'drivers/backlight/backlight_software.c')
| -rw-r--r-- | drivers/backlight/backlight_software.c | 54 | 
1 files changed, 54 insertions, 0 deletions
| diff --git a/drivers/backlight/backlight_software.c b/drivers/backlight/backlight_software.c new file mode 100644 index 0000000000..f2af3e918e --- /dev/null +++ b/drivers/backlight/backlight_software.c @@ -0,0 +1,54 @@ +#include "backlight.h" +#include "backlight_driver_common.h" +#include "util.h" + +#ifdef BACKLIGHT_BREATHING +#    error "Backlight breathing is not available for software PWM. Please disable." +#endif + +static uint16_t s_duty_pattern = 0; + +// clang-format off + +/** \brief PWM duty patterns + * + * We scale the current backlight level to an index within this array. This allows + * backlight_task to focus on just switching LEDs on/off, and we can predict the duty pattern + */ +static const uint16_t backlight_duty_table[] = { +    0b0000000000000000, +    0b1000000000000000, +    0b1000000010000000, +    0b1000001000010000, +    0b1000100010001000, +    0b1001001001001000, +    0b1010101010101010, +    0b1110111011101110, +    0b1111111111111111, +}; +#define backlight_duty_table_size ARRAY_SIZE(backlight_duty_table) + +// clang-format on + +static uint8_t scale_backlight(uint8_t v) { +    return v * (backlight_duty_table_size - 1) / BACKLIGHT_LEVELS; +} + +void backlight_init_ports(void) { +    backlight_pins_init(); +} + +void backlight_set(uint8_t level) { +    s_duty_pattern = backlight_duty_table[scale_backlight(level)]; +} + +void backlight_task(void) { +    static uint8_t backlight_tick = 0; + +    if (s_duty_pattern & ((uint16_t)1 << backlight_tick)) { +        backlight_pins_on(); +    } else { +        backlight_pins_off(); +    } +    backlight_tick = (backlight_tick + 1) % 16; +} | 
