Re: [alsa-devel] [PATCH v2 3/3] ASoC: TDA7802: Add turn-on diagnostic routine

[Thomas Preston <thomas.preston@codethink.co.uk>]

Hi,
Thanks for getting back to me so quickly.

On 30/07/2019 13:41, Charles Keepax wrote:
> On Tue, Jul 30, 2019 at 01:09:37PM +0100, Thomas Preston wrote:
>> Add a debugfs device node which initiates the turn-on diagnostic routine
>> feature of the TDA7802 amplifier. The four status registers (one per
>> channel) are returned.
>>
>> Signed-off-by: Thomas Preston <thomas.preston@codethink.co.uk>
>> ---
>> Changes since v1:
>> - Rename speaker-test to (turn-on) diagnostics
>> - Move turn-on diagnostic to debugfs as there is no standard ALSA
>>   interface for this kind of routine.
>>
>>  sound/soc/codecs/tda7802.c | 186 ++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 185 insertions(+), 1 deletion(-)
>>
>> +static int tda7802_bulk_update(struct regmap *map, struct reg_update *update,
>> +		size_t update_count)
>> +{
>> +	int i, err;
>> +
>> +	for (i = 0; i < update_count; i++) {
>> +		err = regmap_update_bits(map, update[i].reg, update[i].mask,
>> +				update[i].val);
>> +		if (err < 0)
>> +			return err;
>> +	}
>> +
>> +	return i;
>> +}
> 
> This could probably be removed using regmap_multi_reg_write.
> 

The problem is that I want to retain the state of the other bits in those
registers. Maybe I should make a copy of the backed up state, set the bits
I want to off-device, then either:

1. Write the changes with regmap_multi_reg_write
2. Write all six regs again (if my device doesn't support the multi_reg)

>> +static int tda7802_probe(struct snd_soc_component *component)
>> +{
>> +	struct tda7802_priv *tda7802 = snd_soc_component_get_drvdata(component);
>> +	struct device *dev = &tda7802->i2c->dev;
>> +	int err;
>> +
>> +	tda7802->debugfs = debugfs_create_dir(dev_name(dev), NULL);
>> +	if (IS_ERR_OR_NULL(tda7802->debugfs)) {
>> +		dev_info(dev,
>> +			"Failed to create debugfs node, err %ld\n",
>> +			PTR_ERR(tda7802->debugfs));
>> +		return 0;
>> +	}
>> +
>> +	mutex_init(&tda7802->diagnostic_mutex);
>> +	err = debugfs_create_file("diagnostic", 0444, tda7802->debugfs, tda7802,
>> +			&tda7802_diagnostic_fops);
>> +	if (err < 0) {
>> +		dev_err(dev,
>> +			"debugfs: Failed to create diagnostic node, err %d\n",
>> +			err);
>> +		goto cleanup_diagnostic;
>> +	}
> 
> You shouldn't be failing the driver probe if debugfs fails, it
> should be purely optional.
> 

Got it, thanks.