diff options
Diffstat (limited to 'drivers/pwm/pwm-twl-led.c')
| -rw-r--r-- | drivers/pwm/pwm-twl-led.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-twl-led.c b/drivers/pwm/pwm-twl-led.c index ed0b63dd38f1..8fb84b441853 100644 --- a/drivers/pwm/pwm-twl-led.c +++ b/drivers/pwm/pwm-twl-led.c @@ -7,6 +7,22 @@ * * This driver is a complete rewrite of the former pwm-twl6030.c authorded by: * Hemanth V <hemanthv@ti.com> + * + * Reference manual for the twl6030 is available at: + * https://www.ti.com/lit/ds/symlink/twl6030.pdf + * + * Limitations: + * - The twl6030 hardware only supports two period lengths (128 clock ticks and + * 64 clock ticks), the driver only uses 128 ticks + * - The hardware doesn't support ON = 0, so the active part of a period doesn't + * start at its beginning. + * - The hardware could support inverted polarity (with a similar limitation as + * for normal: the last clock tick is always inactive). + * - The hardware emits a constant low output when disabled. + * - A request for .duty_cycle = 0 results in an output wave with one active + * clock tick per period. This should better use the disabled state. + * - The driver only implements setting the relative duty cycle. + * - The driver doesn't implement .get_state(). */ #include <linux/module.h> |