Re: [alsa-devel] [PATCH v6 03/17] mfd: madera: Add common support for Cirrus Logic Madera codecs

2 Dec 2017

      On Wed, Nov 29, 2017 at 12:36 PM, Richard Fitzgerald
rf@opensource.wolfsonmicro.com wrote:
...
On 29/11/17 10:18, Linus Walleij wrote:
...
On Thu, Nov 23, 2017 at 6:13 PM, Richard Fitzgerald
rf@opensource.wolfsonmicro.com wrote:
...
+config MFD_MADERA_I2C

  bool "Cirrus Logic Madera codecs with I2C"

  select MFD_MADERA

  select REGMAP_I2C

  depends on I2C

  depends on PINCTRL

  help

    Support for the Cirrus Logic Madera platform audio SoC

    core functionality controlled via I2C.

+config MFD_MADERA_SPI

  bool "Cirrus Logic Madera codecs with SPI"

  select MFD_MADERA

  select REGMAP_SPI

  depends on SPI_MASTER

  depends on PINCTRL

  help

    Support for the Cirrus Logic Madera platform audio SoC

    core functionality controlled via SPI.

Why do the I2C and SPI subdrivers depend on PINCTRL?
They sure don't seem to be using any pinctrl-specific APIs.
They require PINCTRL even if they don't call any functions on it because the
chip won't work correctly if there isn't a PINCTRL driver to apply the
correct pinmux configuration.
Apply the configuration to what? Sorry I don't get it.
You can't be referring to the internal pin controller of the Madera, since
that has to come up before its pin controller can even be communicated
with.
If you mean it is to apply the configuration to the system SoC where
this coded is connected, this is wrong. There may very well be systems
which have dedicated pins for the codec, atleast in theory. The fact
that your reference board needs this is not a universal requirement,
it should be set up in the machine-specific Kconfig for the reference
board in that case.
Yours,
Linus Walleij