On 2018-11-13 18:24, Russell King - ARM Linux wrote: > On Tue, Nov 13, 2018 at 01:28:40PM +0000, Peter Rosin wrote: >> Hi! >> >> I'm wondering about some programming details regarding the TDA998x >> driver... >> >> The bindings documentation [1] state that one should fill in the >> desired register content of the AP_ENA register. However, I cannot >> find any details anywhere about how one determines what is desired. >> When I look for data sheets on the Internet, all I find is a "short" >> data sheet, which is far from enlightening. There are hints about >> a "full" data sheet in the chapter on legal information of the >> "short" data sheet. Is the "full" data sheet protected by an NDA >> or something? That's the only reason I can find for it not being >> available... >> >> Maybe someone with such a "full" data sheet at hand can enlighten >> me on the workings of this AP_ENA register so that I know what it is >> that I need to fill in? Since it is so difficult to find this info, >> maybe it should be added to the binding? > > There's various public documents for the TDA998x chips, some of which > do contain the register programming information - although we don't > have definitive information for every variant that the driver supports. I have looked, and not found anything. Do you have any pointer? For what chip(s) in the family are there register information? > Even so, that doesn't give us documentation for this register, so we > have to resort to code received from other sources. > > The AP_ENA register "audio port enable" is one bit per AP signal, from > the AP0 pin being bit 0, up to the AP7 pin being bit 7. Thanks! However, in the "short" sheet for the TDA19988 that I have, there is this table: AP0 WS (word select) AP1 S/PDIF input I2S-bus channel 0 AP2 S/PDIF input I2S-bus channel 1 AP3 I2S-bus channel 2 AP4 I2S-bus channel 3 ACLK SCK (I2S-bus clock) AP5 through AP7 are nowhere to be found... Should I assume that ACLK is an alias for AP5, and that the register content should be 0x23 for I2S on channel 0? Or is ACLK not part of the AP_ENA register at all, so that 0x03 is more likely to be correct? Cheers, Peter
