diff options
Diffstat (limited to 'drivers/pwm/pwm-cros-ec.c')
| -rw-r--r-- | drivers/pwm/pwm-cros-ec.c | 58 |
1 files changed, 54 insertions, 4 deletions
diff --git a/drivers/pwm/pwm-cros-ec.c b/drivers/pwm/pwm-cros-ec.c index 89497448d217..09c08dee099e 100644 --- a/drivers/pwm/pwm-cros-ec.c +++ b/drivers/pwm/pwm-cros-ec.c @@ -25,11 +25,39 @@ struct cros_ec_pwm_device { struct pwm_chip chip; }; +/** + * struct cros_ec_pwm - per-PWM driver data + * @duty_cycle: cached duty cycle + */ +struct cros_ec_pwm { + u16 duty_cycle; +}; + static inline struct cros_ec_pwm_device *pwm_to_cros_ec_pwm(struct pwm_chip *c) { return container_of(c, struct cros_ec_pwm_device, chip); } +static int cros_ec_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct cros_ec_pwm *channel; + + channel = kzalloc(sizeof(*channel), GFP_KERNEL); + if (!channel) + return -ENOMEM; + + pwm_set_chip_data(pwm, channel); + + return 0; +} + +static void cros_ec_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct cros_ec_pwm *channel = pwm_get_chip_data(pwm); + + kfree(channel); +} + static int cros_ec_pwm_set_duty(struct cros_ec_device *ec, u8 index, u16 duty) { struct { @@ -96,7 +124,9 @@ static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_state *state) { struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip); - int duty_cycle; + struct cros_ec_pwm *channel = pwm_get_chip_data(pwm); + u16 duty_cycle; + int ret; /* The EC won't let us change the period */ if (state->period != EC_PWM_MAX_DUTY) @@ -108,13 +138,20 @@ static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, */ duty_cycle = state->enabled ? state->duty_cycle : 0; - return cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle); + ret = cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle); + if (ret < 0) + return ret; + + channel->duty_cycle = state->duty_cycle; + + return 0; } static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state) { struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip); + struct cros_ec_pwm *channel = pwm_get_chip_data(pwm); int ret; ret = cros_ec_pwm_get_duty(ec_pwm->ec, pwm->hwpwm); @@ -126,8 +163,19 @@ static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, state->enabled = (ret > 0); state->period = EC_PWM_MAX_DUTY; - /* Note that "disabled" and "duty cycle == 0" are treated the same */ - state->duty_cycle = ret; + /* + * Note that "disabled" and "duty cycle == 0" are treated the same. If + * the cached duty cycle is not zero, used the cached duty cycle. This + * ensures that the configured duty cycle is kept across a disable and + * enable operation and avoids potentially confusing consumers. + * + * For the case of the initial hardware readout, channel->duty_cycle + * will be 0 and the actual duty cycle read from the EC is used. + */ + if (ret == 0 && channel->duty_cycle > 0) + state->duty_cycle = channel->duty_cycle; + else + state->duty_cycle = ret; } static struct pwm_device * @@ -149,6 +197,8 @@ cros_ec_pwm_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) } static const struct pwm_ops cros_ec_pwm_ops = { + .request = cros_ec_pwm_request, + .free = cros_ec_pwm_free, .get_state = cros_ec_pwm_get_state, .apply = cros_ec_pwm_apply, .owner = THIS_MODULE, |