Re: [PATCH v3 05/10] iio: backend: extend features

[Angelo Dureghello <adureghello@baylibre.com>]

On 20/09/24 14:50, Nuno Sá wrote:
> On Thu, 2024-09-19 at 11:20 +0200, Angelo Dureghello wrote:
>> From: Angelo Dureghello <adureghello@baylibre.com>
>>
>> Extend backend features with new calls needed later on this
>> patchset from axi version of ad3552r.
>>
>> The follwoing calls are added:
>>
>> iio_backend_ext_sync_enable
>> 	enable synchronize channels on external trigger
>> iio_backend_ext_sync_disable
>> 	disable synchronize channels on external trigger
>> iio_backend_ddr_enable
>> 	enable ddr bus transfer
>> iio_backend_ddr_disable
>> 	disable ddr bus transfer
>> iio_backend_set_bus_mode
>> 	select the type of bus, so that specific read / write
>> 	operations are performed accordingly
>> iio_backend_buffer_enable
>> 	enable buffer
>> iio_backend_buffer_disable
>> 	disable buffer
>> iio_backend_data_transfer_addr
>> 	define the target register address where the DAC sample
>> 	will be written.
>>
>> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
>> ---
>>   drivers/iio/industrialio-backend.c | 111 +++++++++++++++++++++++++++++++++++++
>>   include/linux/iio/backend.h        |  23 ++++++++
>>   2 files changed, 134 insertions(+)
>>
>> diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-
>> backend.c
>> index 20b3b5212da7..f4802c422dbf 100644
>> --- a/drivers/iio/industrialio-backend.c
>> +++ b/drivers/iio/industrialio-backend.c
>> @@ -718,6 +718,117 @@ static int __devm_iio_backend_get(struct device *dev, struct
>> iio_backend *back)
>>   	return 0;
>>   }
>>   
>> +/**
>> + * iio_backend_ext_sync_enable - Enable external synchronization
>> + * @back: Backend device
>> + *
>> + * Enable synchronization by external signal.
>> + *
>> + * RETURNS:
>> + * 0 on success, negative error number on failure.
>> + */
>> +int iio_backend_ext_sync_enable(struct iio_backend *back)
>> +{
>> +	return iio_backend_op_call(back, ext_sync_enable);
>> +}
>> +EXPORT_SYMBOL_NS_GPL(iio_backend_ext_sync_enable, IIO_BACKEND);
>> +
>> +/**
>> + * iio_backend_ext_sync_disable - Disable external synchronization
>> + * @back: Backend device
>> + *
>> + * Disable synchronization by external signal.
>> + *
>> + * RETURNS:
>> + * 0 on success, negative error number on failure.
>> + */
>> +int iio_backend_ext_sync_disable(struct iio_backend *back)
>> +{
>> +	return iio_backend_op_call(back, ext_sync_disable);
>> +}
>> +EXPORT_SYMBOL_NS_GPL(iio_backend_ext_sync_disable, IIO_BACKEND);
>> +
>> +/**
>> + * iio_backend_ddr_enable - Enable interface DDR (Double Data Rate) mode
>> + * @back: Backend device
>> + *
>> + * Enabling DDR, data is generated by the IP at each front
>> + * (raising and falling) of the bus clock signal.
>> + *
>> + * RETURNS:
>> + * 0 on success, negative error number on failure.
>> + */
>> +int iio_backend_ddr_enable(struct iio_backend *back)
>> +{
>> +	return iio_backend_op_call(back, ddr_enable);
>> +}
>> +EXPORT_SYMBOL_NS_GPL(iio_backend_ddr_enable, IIO_BACKEND);
>> +
>> +/**
>> + * iio_backend_ddr_disable - Disable interface DDR (Double Data Rate) mode
>> + * @back: Backend device
>> + *
>> + * Disabling DDR data is generated byt the IP at rising or falling front
>> + * of the interface clock signal (SDR, Single Data Rate).
>> + *
>> + * RETURNS:
>> + * 0 on success, negative error number on failure.
>> + */
>> +int iio_backend_ddr_disable(struct iio_backend *back)
>> +{
>> +	return iio_backend_op_call(back, ddr_disable);
>> +}
>> +EXPORT_SYMBOL_NS_GPL(iio_backend_ddr_disable, IIO_BACKEND);
>> +
>> +/**
>> + * iio_backend_buffer_enable - Enable iio buffering
>> + * @back: Backend device
>> + *
>> + * Enabling the buffer, buffer data is processed and sent out from the
>> + * bus interface.
>> + *
>> + * RETURNS:
>> + * 0 on success, negative error number on failure.
>> + */
>> +int iio_backend_buffer_enable(struct iio_backend *back)
>> +{
>> +	return iio_backend_op_call(back, buffer_enable);
>> +}
>> +EXPORT_SYMBOL_NS_GPL(iio_backend_buffer_enable, IIO_BACKEND);
>> +
>> +/**
>> + * iio_backend_buffer_disable - Disable iio buffering
>> + * @back: Backend device
>> + *
>> + * Disabling the buffer, buffer data transfer on the bus interface
>> + * is stopped.
>> + *
>> + * RETURNS:
>> + * 0 on success, negative error number on failure.
>> + */
>> +int iio_backend_buffer_disable(struct iio_backend *back)
>> +{
>> +	return iio_backend_op_call(back, buffer_disable);
>> +}
>> +EXPORT_SYMBOL_NS_GPL(iio_backend_buffer_disable, IIO_BACKEND);
>> +
> IIRC, both me and Jonathan had some comments about the above 2 calls? Aren't they
> about buffering? I think I mentioned something about using the same buffer ops as
> typical IIO devices use.

i have now separated iio_backend_ops, keeping buffer enable/disable
for axi-ad3352r case only,

static const struct iio_backend_ops axi_dac_generic_ops = {
     .enable = axi_dac_enable,
     .disable = axi_dac_disable,
     .request_buffer = axi_dac_request_buffer,
     .free_buffer = axi_dac_free_buffer,
     .extend_chan_spec = axi_dac_extend_chan,
     .ext_info_set = axi_dac_ext_info_set,
     .ext_info_get = axi_dac_ext_info_get,
     .data_source_set = axi_dac_data_source_set,
     .set_sample_rate = axi_dac_set_sample_rate,
     .debugfs_reg_access = iio_backend_debugfs_ptr(axi_dac_reg_access),
};

static const struct iio_backend_ops axi_ad3552r_ops = {
     .enable = axi_dac_enable,
     .read_raw = axi_dac_read_raw,
     .request_buffer = axi_dac_request_buffer,
     .data_source_set = axi_dac_data_source_set,
     .ext_sync_enable = axi_dac_ext_sync_enable,
     .ext_sync_disable = axi_dac_ext_sync_disable,
     .ddr_enable = axi_dac_ddr_enable,
     .ddr_disable = axi_dac_ddr_disable,
     .buffer_enable = axi_dac_buffer_enable,
     .buffer_disable = axi_dac_buffer_disable,
     .data_format_set = axi_dac_data_format_set,
     .data_transfer_addr = axi_dac_data_transfer_addr,
};


could this be good ?


> - Nuno Sá

Regards,
Angelo