diff --git a/drivers/iio/adc/ad7606.c b/drivers/iio/adc/ad7606.c index 71362eafe838..8f42d5ad1120 100644 --- a/drivers/iio/adc/ad7606.c +++ b/drivers/iio/adc/ad7606.c @@ -13,10 +13,12 @@ #include #include #include +#include #include #include #include #include +#include #include #include @@ -299,6 +301,73 @@ static int ad7606_reg_access(struct iio_dev *indio_dev, } } +static int ad7606_pwm_set_high(struct ad7606_state *st) +{ + struct pwm_state cnvst_pwm_state; + int ret; + + pwm_get_state(st->cnvst_pwm, &cnvst_pwm_state); + cnvst_pwm_state.enabled = true; + cnvst_pwm_state.duty_cycle = cnvst_pwm_state.period; + + ret = pwm_apply_might_sleep(st->cnvst_pwm, &cnvst_pwm_state); + /* sleep 2 µS to let finish the current pulse */ + fsleep(2); + + return ret; +} + +static int ad7606_pwm_set_low(struct ad7606_state *st) +{ + struct pwm_state cnvst_pwm_state; + int ret; + + pwm_get_state(st->cnvst_pwm, &cnvst_pwm_state); + cnvst_pwm_state.enabled = true; + cnvst_pwm_state.duty_cycle = 0; + + ret = pwm_apply_might_sleep(st->cnvst_pwm, &cnvst_pwm_state); + /* sleep 2 µS to let finish the current pulse */ + fsleep(2); + + return ret; +} + +static bool ad7606_pwm_is_swinging(struct ad7606_state *st) +{ + struct pwm_state cnvst_pwm_state; + + pwm_get_state(st->cnvst_pwm, &cnvst_pwm_state); + + return cnvst_pwm_state.duty_cycle != cnvst_pwm_state.period && + cnvst_pwm_state.duty_cycle != 0; +} + +static int ad7606_set_sampling_freq(struct ad7606_state *st, unsigned long freq) +{ + struct pwm_state cnvst_pwm_state; + bool is_swinging = ad7606_pwm_is_swinging(st); + bool is_high; + + if (freq == 0) + return -EINVAL; + + /* Retrieve the previous state. */ + pwm_get_state(st->cnvst_pwm, &cnvst_pwm_state); + is_high = cnvst_pwm_state.duty_cycle == cnvst_pwm_state.period; + + cnvst_pwm_state.period = DIV_ROUND_UP_ULL(NSEC_PER_SEC, freq); + cnvst_pwm_state.polarity = PWM_POLARITY_NORMAL; + if (is_high) + cnvst_pwm_state.duty_cycle = cnvst_pwm_state.period; + else if (is_swinging) + cnvst_pwm_state.duty_cycle = cnvst_pwm_state.period / 2; + else + cnvst_pwm_state.duty_cycle = 0; + + return pwm_apply_might_sleep(st->cnvst_pwm, &cnvst_pwm_state); +} + static int ad7606_read_samples(struct ad7606_state *st) { unsigned int num = st->chip_info->num_channels - 1; @@ -324,7 +393,13 @@ static irqreturn_t ad7606_trigger_handler(int irq, void *p) error_ret: iio_trigger_notify_done(indio_dev->trig); /* The rising edge of the CONVST signal starts a new conversion. */ - gpiod_set_value(st->gpio_convst, 1); + if (st->gpio_convst) { + gpiod_set_value(st->gpio_convst, 1); + } else { + ret = ad7606_pwm_set_high(st); + if (ret < 0) + dev_err(st->dev, "Could not set PWM to high."); + } return IRQ_HANDLED; } @@ -337,7 +412,13 @@ static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch, const struct iio_chan_spec *chan; int ret; - gpiod_set_value(st->gpio_convst, 1); + if (st->gpio_convst) { + gpiod_set_value(st->gpio_convst, 1); + } else { + ret = ad7606_pwm_set_high(st); + if (ret < 0) + return ret; + } ret = wait_for_completion_timeout(&st->completion, msecs_to_jiffies(1000)); if (!ret) { @@ -363,6 +444,11 @@ static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch, } error_ret: + if (!st->gpio_convst) { + ret = ad7606_pwm_set_low(st); + if (ret < 0) + return ret; + } gpiod_set_value(st->gpio_convst, 0); return ret; @@ -662,8 +748,9 @@ static int ad7606_request_gpios(struct ad7606_state *st) { struct device *dev = st->dev; - st->gpio_convst = devm_gpiod_get(dev, "adi,conversion-start", - GPIOD_OUT_LOW); + st->gpio_convst = devm_gpiod_get_optional(dev, "adi,conversion-start", + GPIOD_OUT_LOW); + if (IS_ERR(st->gpio_convst)) return PTR_ERR(st->gpio_convst); @@ -705,14 +792,24 @@ static irqreturn_t ad7606_interrupt(int irq, void *dev_id) { struct iio_dev *indio_dev = dev_id; struct ad7606_state *st = iio_priv(indio_dev); + int ret; if (iio_buffer_enabled(indio_dev)) { - gpiod_set_value(st->gpio_convst, 0); + if (st->gpio_convst) { + gpiod_set_value(st->gpio_convst, 0); + } else { + ret = ad7606_pwm_set_low(st); + if (ret < 0) { + dev_err(st->dev, "PWM set low failed"); + goto done; + } + } iio_trigger_poll_nested(st->trig); } else { complete(&st->completion); } +done: return IRQ_HANDLED; }; @@ -731,7 +828,10 @@ static int ad7606_buffer_postenable(struct iio_dev *indio_dev) { struct ad7606_state *st = iio_priv(indio_dev); - gpiod_set_value(st->gpio_convst, 1); + if (st->gpio_convst) + gpiod_set_value(st->gpio_convst, 1); + else + return ad7606_pwm_set_high(st); return 0; } @@ -740,7 +840,10 @@ static int ad7606_buffer_predisable(struct iio_dev *indio_dev) { struct ad7606_state *st = iio_priv(indio_dev); - gpiod_set_value(st->gpio_convst, 0); + if (st->gpio_convst) + gpiod_set_value(st->gpio_convst, 0); + else + return ad7606_pwm_set_low(st); return 0; } @@ -874,6 +977,11 @@ static int ad7606_chan_scales_setup(struct iio_dev *indio_dev) return 0; } +static void ad7606_pwm_disable(void *data) +{ + pwm_disable(data); +} + int ad7606_probe(struct device *dev, int irq, void __iomem *base_address, const char *name, unsigned int id, const struct ad7606_bus_ops *bops) @@ -950,6 +1058,31 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address, if (ret) return ret; + /* If convst pin is not defined, setup PWM. */ + if (!st->gpio_convst) { + st->cnvst_pwm = devm_pwm_get(dev, NULL); + if (IS_ERR(st->cnvst_pwm)) + return PTR_ERR(st->cnvst_pwm); + + /* The PWM is initialized at 1MHz to have a fast enough GPIO emulation. */ + ret = ad7606_set_sampling_freq(st, 1 * MEGA); + if (ret) + return ret; + + ret = ad7606_pwm_set_low(st); + if (ret) + return ret; + + /* + * PWM is not disabled when sampling stops, but instead its duty cycle is set + * to 0% to be sure we have a "low" state. After we unload the driver, let's + * disable the PWM. + */ + ret = devm_add_action_or_reset(dev, ad7606_pwm_disable, + st->cnvst_pwm); + if (ret) + return ret; + } st->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name, iio_device_id(indio_dev)); diff --git a/drivers/iio/adc/ad7606.h b/drivers/iio/adc/ad7606.h index fc05a4afa3b8..760cf5e2ecb6 100644 --- a/drivers/iio/adc/ad7606.h +++ b/drivers/iio/adc/ad7606.h @@ -115,6 +115,7 @@ struct ad7606_chan_scale { * @bops bus operations (SPI or parallel) * @chan_scales scale configuration for channels * @oversampling oversampling selection + * @cnvst_pwm pointer to the PWM device connected to the cnvst pin * @base_address address from where to read data in parallel operation * @sw_mode_en software mode enabled * @oversampling_avail pointer to the array which stores the available @@ -142,6 +143,7 @@ struct ad7606_state { const struct ad7606_bus_ops *bops; struct ad7606_chan_scale chan_scales[AD760X_MAX_CHANNELS]; unsigned int oversampling; + struct pwm_device *cnvst_pwm; void __iomem *base_address; bool sw_mode_en; const unsigned int *oversampling_avail;