Re: [PATCH v3] ASoC: tas2783: Add source files for tas2783 driver.

[Pierre-Louis Bossart]

On 10/30/23 12:40, Pierre-Louis Bossart wrote:
> 
> 
> On 10/30/23 12:20, Mark Brown wrote:
>> On Mon, Oct 30, 2023 at 11:05:39AM -0500, Pierre-Louis Bossart wrote:
>>
>>>> +static bool tas2783_readable_register(struct device *dev, unsigned int reg)
>>>> +{
>>>> +	switch (reg) {
>>>> +	case 0x000 ... 0x080:	/* Data port 0. */
>>
>>> No, this is wrong. All the data port 'standard' registers are "owned" by
>>> the SoundWire core and handled during the port prepare/configure/bank
>>> switch routines. Do not use them for regmap.
>>
>>> In other words, you *shall* only define vendor-specific registers in
>>> this codec driver.
>>
>> This seems to come up a moderate amount and is an understandable thing
>> to do - could you (or someone else who knows SoundWire) perhaps send a
>> patch for the regmap SoundWire integration which does some validation
>> here during registration and at least prints a warning?
> 
> Good suggestion, we could indeed check that the registers are NOT in the
> range [0,0xBF] for all ports - only the range [0xC0..FF] is allowed for
> implementation-defined values. I'll try to cook something up.

After checking, the following ranges are invalid for codec drivers:

for address < 0x1000
LSB = 0x00 - 0xBF standard or reserved

0x1800 – 0x1FFF reserved
0x48000000 - 0xFFFFFFFF reserved

is the recommendation to check the regmap_config and its 'yes_ranges'?

Presumably if the range_min or range_max is within the invalid values
above then the configuration can be tagged as problematic in the dmesg
log or rejected with an error code?