| Message ID | 20240830201627.298264-3-abhashkumarjha123@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | Continuous mode support for VL53l0x | expand |
On Sat, 31 Aug 2024 01:46:26 +0530 Abhash Jha <abhashkumarjha123@gmail.com> wrote: > The continuous mode of the sensor is enabled in the buffer_postenable. > Replaced the original irq handler with a threaded irq handler to perform > i2c reads during continuous mode. > The continuous mode is disabled by disabling the buffer. > > Signed-off-by: Abhash Jha <abhashkumarjha123@gmail.com> Hi Abhash, You've ended up with an implementation that is somewhere between a triggered buffer approach (normal one an appropriate here) and that used when we don't have triggers (typically because there is a fifo in the path). Please take a look at how other drivers do this. In particularly if you are not pushing data to the buffer from the pollfunc (registered for the triggered buffer) then you are doing it wrong. Also, consider if other triggers could be used as if not you need to both document why and add the validation callbacks to stop other triggers being assigned (once you've added one that can be!) Feel free to ask if you have more questions, but your first reference should be other drivers (and I hope we don't have any that do it this way). Jonathan > --- > drivers/iio/proximity/vl53l0x-i2c.c | 125 ++++++++++++++++++++++------ > 1 file changed, 101 insertions(+), 24 deletions(-) > > diff --git a/drivers/iio/proximity/vl53l0x-i2c.c b/drivers/iio/proximity/vl53l0x-i2c.c > index 2b3dd18be..b0c947586 100644 > --- a/drivers/iio/proximity/vl53l0x-i2c.c > +++ b/drivers/iio/proximity/vl53l0x-i2c.c > @@ -22,6 +22,10 @@ > #include <linux/module.h> > > #include <linux/iio/iio.h> > +#include <linux/iio/buffer.h> > +#include <linux/iio/trigger.h> > +#include <linux/iio/trigger_consumer.h> > +#include <linux/iio/triggered_buffer.h> > > #define VL_REG_SYSRANGE_START 0x00 > > @@ -49,14 +53,58 @@ struct vl53l0x_data { > struct completion completion; > struct regulator *vdd_supply; > struct gpio_desc *reset_gpio; > + > + struct { > + u16 chan; > + s64 timestamp __aligned(8); > + } scan; > }; > > -static irqreturn_t vl53l0x_handle_irq(int irq, void *priv) > +static void vl53l0x_clear_irq(struct vl53l0x_data *data) > +{ > + struct device *dev = &data->client->dev; > + int ret; > + > + ret = i2c_smbus_write_byte_data(data->client, > + VL_REG_SYSTEM_INTERRUPT_CLEAR, 1); > + if (ret < 0) > + dev_err(dev, "failed to clear error irq: %d\n", ret); > + > + ret = i2c_smbus_write_byte_data(data->client, > + VL_REG_SYSTEM_INTERRUPT_CLEAR, 0); > + if (ret < 0) > + dev_err(dev, "failed to clear range irq: %d\n", ret); ouch, not a write 1 to clear register? I can't find docs, but this is really nasty bit of interface design if you have to toggle the bit. > + > + ret = i2c_smbus_read_byte_data(data->client, VL_REG_RESULT_INT_STATUS); > + if (ret < 0 || ret & 0x07) > + dev_err(dev, "failed to clear irq: %d\n", ret); return an error from this, and elect whether to do anything or not with that at the caller. > +} > + > +static irqreturn_t vl53l0x_threaded_irq(int irq, void *priv) > { > struct iio_dev *indio_dev = priv; > struct vl53l0x_data *data = iio_priv(indio_dev); > + u8 buffer[12]; See below for more comments, but this is not a triggered buffer setup. It looks like what we do when draining fifos (where a trigger concept doesn't apply) but that's not what you have here. So take a look at how the split trigger / triggered buffer approach works in other drivers. > + int ret; > > - complete(&data->completion); > + if (iio_buffer_enabled(indio_dev)) { > + ret = i2c_smbus_read_i2c_block_data(data->client, > + VL_REG_RESULT_RANGE_STATUS, > + sizeof(buffer), buffer); > + if (ret < 0) > + return ret; > + else if (ret != 12) > + return -EREMOTEIO; > + > + data->scan.chan = (buffer[10] << 8) + buffer[11]; get_unaligned_be16() > + iio_push_to_buffers_with_timestamp(indio_dev, > + &data->scan, > + iio_get_time_ns(indio_dev)); If you are using a trigger (and they are optional) then this interrupt should only be call iio_trigger_poll_nested() not do the data reading. > + > + iio_trigger_notify_done(indio_dev->trig); > + vl53l0x_clear_irq(data); > + } else > + complete(&data->completion); > > return IRQ_HANDLED; > } > > -static void vl53l0x_clear_irq(struct vl53l0x_data *data) > -{ > - struct device *dev = &data->client->dev; > - int ret; > - > - ret = i2c_smbus_write_byte_data(data->client, > - VL_REG_SYSTEM_INTERRUPT_CLEAR, 1); > - if (ret < 0) > - dev_err(dev, "failed to clear error irq: %d\n", ret); > - > - ret = i2c_smbus_write_byte_data(data->client, > - VL_REG_SYSTEM_INTERRUPT_CLEAR, 0); > - if (ret < 0) > - dev_err(dev, "failed to clear range irq: %d\n", ret); > - > - ret = i2c_smbus_read_byte_data(data->client, VL_REG_RESULT_INT_STATUS); > - if (ret < 0 || ret & 0x07) > - dev_err(dev, "failed to clear irq: %d\n", ret); > -} > - > > static int vl53l0x_read_raw(struct iio_dev *indio_dev, > @@ -221,6 +257,40 @@ static int vl53l0x_power_on(struct vl53l0x_data *data) > return 0; > } > > +static int vl53l0x_buffer_postenable(struct iio_dev *indio_dev) > +{ > + struct vl53l0x_data *data = iio_priv(indio_dev); > + int ret; > + > + ret = i2c_smbus_write_byte_data(data->client, VL_REG_SYSRANGE_START, 0x02); return i2c_smbus_write_byte_data() > + if (ret < 0) > + return ret; > + > + return 0; > +} > + > +static int vl53l0x_buffer_postdisable(struct iio_dev *indio_dev) > +{ > + struct vl53l0x_data *data = iio_priv(indio_dev); > + int ret; > + > + ret = i2c_smbus_write_byte_data(data->client, VL_REG_SYSRANGE_START, 0x01); > + if (ret < 0) > + return ret; > + > + /* Let the ongoing reading finish */ > + reinit_completion(&data->completion); > + wait_for_completion_timeout(&data->completion, HZ/10); Spaces around / > + vl53l0x_clear_irq(data); > + > + return 0; > +} > static int vl53l0x_probe(struct i2c_client *client) > { > struct vl53l0x_data *data; > @@ -279,6 +349,13 @@ static int vl53l0x_probe(struct i2c_client *client) > ret = vl53l0x_configure_irq(client, indio_dev); > if (ret) > return ret; > + > + ret = devm_iio_triggered_buffer_setup(&client->dev, > + indio_dev, > + &iio_pollfunc_store_time, This is odd. You don't seem to have a function to be called to actually store the data. Note you also need to consider if other triggers might be used. Ultimately this doesn't look like a triggered buffer to me. It is fine for some devices to drive the buffer directly but in that case register the kfifo buffer. I'm not sure what reason we have to do that here though as this is a very conventional one interrupt per 'scan' of data device. So you should be registering a trigger, and a buffer then letting the trigger drive the buffer. > + NULL, &iio_triggered_buffer_setup_ops); > + if (ret) > + return ret; > } > > return devm_iio_device_register(&client->dev, indio_dev);
> Also, consider if other triggers could be used as if not you need to > both document why and add the validation callbacks to stop other triggers > being assigned (once you've added one that can be!) > > Feel free to ask if you have more questions, but your first reference > should be other drivers (and I hope we don't have any that do it this way). > I used this driver as a reference https://github.com/torvalds/linux/blob/master/drivers/iio/adc/vf610_adc.c#L556 > > ouch, not a write 1 to clear register? I can't find docs, but this is really > nasty bit of interface design if you have to toggle the bit. > Actually ST has not provided a register map or any application note for the sensor. So there's no way to cross reference. Hence I kept the original code. But I will try to write 1 to clear register with my sensor. > > + ret = devm_iio_triggered_buffer_setup(&client->dev, > > + indio_dev, > > + &iio_pollfunc_store_time, > > This is odd. You don't seem to have a function to be called to actually store > the data. Note you also need to consider if other triggers might be used. > > I'm not sure what reason we have to do that here though as this is a very > conventional one interrupt per 'scan' of data device. > > So you should be registering a trigger, and a buffer then letting the > trigger drive the buffer. Why do I need to register a trigger? Would it be fine to let the irq fill the buffer with data as it continuously reads it in the poll function? So according to my understanding, I need to move all the data reading and pushing to the poll function and not do it in the irq handler. Then register that poll function here during iio_triggered_buffer_setup. Is there something that I am missing? Regards, Abhash
On Sat, 31 Aug 2024 22:12:27 +0530 Abhash jha <abhashkumarjha123@gmail.com> wrote: > > Also, consider if other triggers could be used as if not you need to > > both document why and add the validation callbacks to stop other triggers > > being assigned (once you've added one that can be!) > > > > Feel free to ask if you have more questions, but your first reference > > should be other drivers (and I hope we don't have any that do it this way). > > > I used this driver as a reference > https://github.com/torvalds/linux/blob/master/drivers/iio/adc/vf610_adc.c#L556 ouch. Whilst that's an ancient driver, its unfortunately handling the buffer completely wrongly :( It's old enough that I suspect there will be no interest in improving that one. > > > > > ouch, not a write 1 to clear register? I can't find docs, but this is really > > nasty bit of interface design if you have to toggle the bit. > > > Actually ST has not provided a register map or any application note > for the sensor. > So there's no way to cross reference. Hence I kept the original code. > But I will try to write 1 to clear register with my sensor. > > > > + ret = devm_iio_triggered_buffer_setup(&client->dev, > > > + indio_dev, > > > + &iio_pollfunc_store_time, > > > > This is odd. You don't seem to have a function to be called to actually store > > the data. Note you also need to consider if other triggers might be used. > > > > I'm not sure what reason we have to do that here though as this is a very > > conventional one interrupt per 'scan' of data device. > > > > So you should be registering a trigger, and a buffer then letting the > > trigger drive the buffer. > > Why do I need to register a trigger? Would it be fine to let the irq > fill the buffer > with data as it continuously reads it in the poll function? That is a possibility but it's not nearly as flexible as providing a trigger so we generally only do that if there is a fifo in the way so no 'per scan' signal is available. The model of IIO is that you may associate different triggers with a device and each trigger can drive capture from multiple devices allowing reasonable data synchronisation. There are lots of devices that don't have a sequencer / 'continuous' mode and we want the interface to looks the same for those as it does for those that do have such support. > > So according to my understanding, > I need to move all the data reading and pushing to the poll function > and not do it in the irq handler. > Then register that poll function here during iio_triggered_buffer_setup. > Is there something that I am missing? You have it right. The only other thing is to work out if it is possible to use other triggers with the device (I can't see why you wouldn't be able to use this trigger to drive other device). Sometimes using other triggers requires a slightly more complex sequence so you can check if using a devices own trigger or not and modify what goes on if it is a different trigger. If multiple trigger support is complex, it is fine to start out with providing a trigger validation function iio_info->validate_trigger() and there is an iio_validate_own_trigger() that you can use to avoid having to code anything. That relies on the iio_trigger and the iio_device having the same parent (which they should do here). Jonathan > > Regards, > Abhash
diff --git a/drivers/iio/proximity/vl53l0x-i2c.c b/drivers/iio/proximity/vl53l0x-i2c.c index 2b3dd18be..b0c947586 100644 --- a/drivers/iio/proximity/vl53l0x-i2c.c +++ b/drivers/iio/proximity/vl53l0x-i2c.c @@ -22,6 +22,10 @@ #include <linux/module.h> #include <linux/iio/iio.h> +#include <linux/iio/buffer.h> +#include <linux/iio/trigger.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> #define VL_REG_SYSRANGE_START 0x00 @@ -49,14 +53,58 @@ struct vl53l0x_data { struct completion completion; struct regulator *vdd_supply; struct gpio_desc *reset_gpio; + + struct { + u16 chan; + s64 timestamp __aligned(8); + } scan; }; -static irqreturn_t vl53l0x_handle_irq(int irq, void *priv) +static void vl53l0x_clear_irq(struct vl53l0x_data *data) +{ + struct device *dev = &data->client->dev; + int ret; + + ret = i2c_smbus_write_byte_data(data->client, + VL_REG_SYSTEM_INTERRUPT_CLEAR, 1); + if (ret < 0) + dev_err(dev, "failed to clear error irq: %d\n", ret); + + ret = i2c_smbus_write_byte_data(data->client, + VL_REG_SYSTEM_INTERRUPT_CLEAR, 0); + if (ret < 0) + dev_err(dev, "failed to clear range irq: %d\n", ret); + + ret = i2c_smbus_read_byte_data(data->client, VL_REG_RESULT_INT_STATUS); + if (ret < 0 || ret & 0x07) + dev_err(dev, "failed to clear irq: %d\n", ret); +} + +static irqreturn_t vl53l0x_threaded_irq(int irq, void *priv) { struct iio_dev *indio_dev = priv; struct vl53l0x_data *data = iio_priv(indio_dev); + u8 buffer[12]; + int ret; - complete(&data->completion); + if (iio_buffer_enabled(indio_dev)) { + ret = i2c_smbus_read_i2c_block_data(data->client, + VL_REG_RESULT_RANGE_STATUS, + sizeof(buffer), buffer); + if (ret < 0) + return ret; + else if (ret != 12) + return -EREMOTEIO; + + data->scan.chan = (buffer[10] << 8) + buffer[11]; + iio_push_to_buffers_with_timestamp(indio_dev, + &data->scan, + iio_get_time_ns(indio_dev)); + + iio_trigger_notify_done(indio_dev->trig); + vl53l0x_clear_irq(data); + } else + complete(&data->completion); return IRQ_HANDLED; } @@ -71,8 +119,9 @@ static int vl53l0x_configure_irq(struct i2c_client *client, if (!irq_flags) irq_flags = IRQF_TRIGGER_FALLING; - ret = devm_request_irq(&client->dev, client->irq, vl53l0x_handle_irq, - irq_flags, indio_dev->name, indio_dev); + ret = devm_request_threaded_irq(&client->dev, client->irq, + NULL, vl53l0x_threaded_irq, + irq_flags | IRQF_ONESHOT, indio_dev->name, indio_dev); if (ret) { dev_err(&client->dev, "devm_request_irq error: %d\n", ret); return ret; @@ -87,26 +136,6 @@ static int vl53l0x_configure_irq(struct i2c_client *client, return ret; } -static void vl53l0x_clear_irq(struct vl53l0x_data *data) -{ - struct device *dev = &data->client->dev; - int ret; - - ret = i2c_smbus_write_byte_data(data->client, - VL_REG_SYSTEM_INTERRUPT_CLEAR, 1); - if (ret < 0) - dev_err(dev, "failed to clear error irq: %d\n", ret); - - ret = i2c_smbus_write_byte_data(data->client, - VL_REG_SYSTEM_INTERRUPT_CLEAR, 0); - if (ret < 0) - dev_err(dev, "failed to clear range irq: %d\n", ret); - - ret = i2c_smbus_read_byte_data(data->client, VL_REG_RESULT_INT_STATUS); - if (ret < 0 || ret & 0x07) - dev_err(dev, "failed to clear irq: %d\n", ret); -} - static int vl53l0x_read_proximity(struct vl53l0x_data *data, const struct iio_chan_spec *chan, int *val) @@ -163,7 +192,14 @@ static const struct iio_chan_spec vl53l0x_channels[] = { .type = IIO_DISTANCE, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .scan_index = 0, + .scan_type = { + .sign = 'u', + .realbits = 12, + .storagebits = 16, + }, }, + IIO_CHAN_SOFT_TIMESTAMP(32), }; static int vl53l0x_read_raw(struct iio_dev *indio_dev, @@ -221,6 +257,40 @@ static int vl53l0x_power_on(struct vl53l0x_data *data) return 0; } +static int vl53l0x_buffer_postenable(struct iio_dev *indio_dev) +{ + struct vl53l0x_data *data = iio_priv(indio_dev); + int ret; + + ret = i2c_smbus_write_byte_data(data->client, VL_REG_SYSRANGE_START, 0x02); + if (ret < 0) + return ret; + + return 0; +} + +static int vl53l0x_buffer_postdisable(struct iio_dev *indio_dev) +{ + struct vl53l0x_data *data = iio_priv(indio_dev); + int ret; + + ret = i2c_smbus_write_byte_data(data->client, VL_REG_SYSRANGE_START, 0x01); + if (ret < 0) + return ret; + + /* Let the ongoing reading finish */ + reinit_completion(&data->completion); + wait_for_completion_timeout(&data->completion, HZ/10); + vl53l0x_clear_irq(data); + + return 0; +} + +static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = { + .postenable = &vl53l0x_buffer_postenable, + .postdisable = &vl53l0x_buffer_postdisable, +}; + static int vl53l0x_probe(struct i2c_client *client) { struct vl53l0x_data *data; @@ -279,6 +349,13 @@ static int vl53l0x_probe(struct i2c_client *client) ret = vl53l0x_configure_irq(client, indio_dev); if (ret) return ret; + + ret = devm_iio_triggered_buffer_setup(&client->dev, + indio_dev, + &iio_pollfunc_store_time, + NULL, &iio_triggered_buffer_setup_ops); + if (ret) + return ret; } return devm_iio_device_register(&client->dev, indio_dev);
The continuous mode of the sensor is enabled in the buffer_postenable. Replaced the original irq handler with a threaded irq handler to perform i2c reads during continuous mode. The continuous mode is disabled by disabling the buffer. Signed-off-by: Abhash Jha <abhashkumarjha123@gmail.com> --- drivers/iio/proximity/vl53l0x-i2c.c | 125 ++++++++++++++++++++++------ 1 file changed, 101 insertions(+), 24 deletions(-)