Thank you Mark for the constructive feedback ! A few follow-up questions below. On Thu, Apr 16, 2020 at 8:42 AM Mark Brown <broonie@xxxxxxxxxx> wrote: > > > +++ b/sound/soc/codecs/zl38060.c > > @@ -0,0 +1,643 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +/* > > + * Codec driver for Microsemi ZL38060 Connected Home Audio Processor. > > + * > > Please make the entire comment a C++ one so things look more > intentional. The 'weird' combination of // SPDX and /* Description/copyright */ seems to be a kernel-wide standard (for C files, at least) ? E.g.: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/codecs/wm9090.c?h=v5.7-rc1#n2 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/codecs/wm8904.c?h=v5.7-rc1#n2 Ok to keep? > > > +skip_setup: > > + if (priv->amp_en_gpio && tx) { > > + /* enable the external amplifier before playback starts */ > > + gpiod_set_value_cansleep(priv->amp_en_gpio, 1); > > + if (priv->amp_startup_delay_ms) > > + msleep(priv->amp_startup_delay_ms); > > + } > > This external amplifier support shouldn't be here, if there's other > devices in the system then they will have their own drivers and the > machine driver will take care of linking things together. In our application, the amp is a "dumb" class-D amp with a single enable line: https://www.onsemi.com/pub/Collateral/FAB3103-D.pdf I am not sure how I could make this more general. Could you point me to an example somewhere in the tree? > > > + priv->regmap = devm_regmap_init(dev, &zl38_regmap_bus, spi, > > + &zl38_regmap_conf); > > + if (IS_ERR(priv->regmap)) > > + return PTR_ERR(priv->regmap); > > devm_regmap_init_spi() I wish !! This chip has complex SPI addressing, using an "address" which: - is variable length, depending on the page of the register being accessed; - contains a field with the length of the data to follow. Unfortunately, during firmware programming, multi-writes are mandatory (usually address header + 32 data bytes). Implementing my own regmap_bus looked like the only way out.