Messages in this thread | | | From | Peter Rosin <> | Subject | [v2] NXP Semiconductors TFA9879 Amplifier Driver | Date | Thu, 6 Nov 2014 17:39:44 +0100 |
| |
On 2014-11-06 17:02, Mark Brown wrote:> On Thu, Nov 06, 2014 at 02:37:31PM +0000, Peter Rosin wrote: >> > Mark Brown wrote: >>>> > > > + if (tfa9879->lsb_justified) >>>> > > > + TFA9879_REG(codec, SERIAL_INTERFACE_1, I2S_SET, i2s_set); >>> > > Why does this need to be reset every time, shouldn't we just be setting the >>> > > register in set_fmt().? >> > Yes, I'd sure like to do that, but how do I get to the width in set_fmt()? > Oh, this has some width related thing in it?
Yes, the amp has a different setting for each lsb-justified width. (It also supports 18 and 20 bits wide data)
>>>> > > > + { TFA9879_MISC_STATUS, 0x0000 }, /* 0x15, read-only */ >>>> > > > +}; >>>> > > > +static bool tfa9879_volatile_register(struct device *dev, unsigned >>>> > > > +int reg) { >>>> > > > + return reg == TFA9879_MISC_STATUS; >>> > > If the register is volatile it shouldn't have a default value provided. >> > Then I misunderstood what volatile was meant to do. I'll just nuke the >> > function. It works fine anyway... > A volatile register is one that the chip may change autonomously (eg, an > interrupt status register).
That was what I assumed, and the register behaves like that. I naively thought that declaring it as volatile would prevent the asoc core from writing to it. In retrospect, I don't understand why I thought that... Anyway, that bit can wait until someone actually needs to read the staus.
Here's an update with the following changes since v1:
- squashed patch 2/2 - zapped the TFA9879_REG macro - zapped tfa9879_probe (which needlessly registered the regmap) - moved tfa9879_prepare/_shutdown to a DAPM_SUPPLY widget - zapped the tfa9879_volatile() thing - made tfa9879_dai_ops const - erased the redundant "Gain" from the bass/treble volume controls - using params_width() instead of params_format()
Cheers, Peter
| |