diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/pwm/pwm-sti.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c index bd753fbad08a..95014f57a9c6 100644 --- a/drivers/pwm/pwm-sti.c +++ b/drivers/pwm/pwm-sti.c @@ -305,7 +305,90 @@ static void sti_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) clear_bit(pwm->hwpwm, &pc->configured); } +static int sti_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_capture *result, unsigned long timeout) +{ + struct sti_pwm_chip *pc = to_sti_pwmchip(chip); + struct sti_pwm_compat_data *cdata = pc->cdata; + struct sti_cpt_ddata *ddata = pwm_get_chip_data(pwm); + struct device *dev = pc->dev; + unsigned int effective_ticks; + unsigned long long high, low; + int ret; + + if (pwm->hwpwm >= cdata->cpt_num_devs) { + dev_err(dev, "device %u is not valid\n", pwm->hwpwm); + return -EINVAL; + } + + mutex_lock(&ddata->lock); + ddata->index = 0; + + /* Prepare capture measurement */ + regmap_write(pc->regmap, PWM_CPT_EDGE(pwm->hwpwm), CPT_EDGE_RISING); + regmap_field_write(pc->pwm_cpt_int_en, BIT(pwm->hwpwm)); + + /* Enable capture */ + ret = regmap_field_write(pc->pwm_cpt_en, 1); + if (ret) { + dev_err(dev, "failed to enable PWM capture %u: %d\n", + pwm->hwpwm, ret); + goto out; + } + + ret = wait_event_interruptible_timeout(ddata->wait, ddata->index > 1, + msecs_to_jiffies(timeout)); + + regmap_write(pc->regmap, PWM_CPT_EDGE(pwm->hwpwm), CPT_EDGE_DISABLED); + + if (ret == -ERESTARTSYS) + goto out; + + switch (ddata->index) { + case 0: + case 1: + /* + * Getting here could mean: + * - input signal is constant of less than 1 Hz + * - there is no input signal at all + * + * In such case the frequency is rounded down to 0 + */ + result->period = 0; + result->duty_cycle = 0; + + break; + + case 2: + /* We have everying we need */ + high = ddata->snapshot[1] - ddata->snapshot[0]; + low = ddata->snapshot[2] - ddata->snapshot[1]; + + effective_ticks = clk_get_rate(pc->cpt_clk); + + result->period = (high + low) * NSEC_PER_SEC; + result->period /= effective_ticks; + + result->duty_cycle = high * NSEC_PER_SEC; + result->duty_cycle /= effective_ticks; + + break; + + default: + dev_err(dev, "internal error\n"); + break; + } + +out: + /* Disable capture */ + regmap_field_write(pc->pwm_cpt_en, 0); + + mutex_unlock(&ddata->lock); + return ret; +} + static const struct pwm_ops sti_pwm_ops = { + .capture = sti_pwm_capture, .config = sti_pwm_config, .enable = sti_pwm_enable, .disable = sti_pwm_disable, @@ -418,6 +501,11 @@ static int sti_pwm_probe_dt(struct sti_pwm_chip *pc) if (IS_ERR(pc->pwm_out_en)) return PTR_ERR(pc->pwm_out_en); + pc->pwm_cpt_en = devm_regmap_field_alloc(dev, pc->regmap, + reg_fields[PWM_CPT_EN]); + if (IS_ERR(pc->pwm_cpt_en)) + return PTR_ERR(pc->pwm_cpt_en); + pc->pwm_cpt_int_en = devm_regmap_field_alloc(dev, pc->regmap, reg_fields[PWM_CPT_INT_EN]); if (IS_ERR(pc->pwm_cpt_int_en)) |