On Mon, 2020-08-31 at 19:06 -0300, Santiago Hormazabal wrote:
> This chip requires almost no support components and can used over I2C.
> The driver uses the I2C bus and exposes the controls as a V4L2 radio.
> Tested with a module that contains this chip (from SZZSJDZ.com,
> part number ZJ-801B, even tho the company seems defunct now), and an H2+
> AllWinner SoC running a kernel built off 07d999f of the media_tree.
Thanks.
style trivia:
[]
> diff --git a/drivers/media/radio/radio-kt0913.c
> b/drivers/media/radio/radio-kt0913.c
[]
> +static const struct reg_sequence kt0913_init_regs_to_defaults[] = {
> + /* Standby disabled, volume 0dB */
> + { KT0913_REG_RXCFG, 0x881f },
These might be more legible on single lines,
ignoring the 80 column limits.
> + /* FM Channel spacing = 50kHz, Right & Left unmuted */
> + { KT0913_REG_SEEK, 0x000b },
etc...
[]
> +static int __kt0913_set_fm_frequency(struct kt0913_device *radio,
> + unsigned int frequency)
> +{
> + return regmap_write(radio->regmap, KT0913_REG_TUNE,
> + KT0913_TUNE_FMTUNE_ON | (frequency / KT0913_FMCHAN_MUL));
It might be nicer to align multi-line statements to the
open parenthesis.
[]
> +static int __kt0913_set_au_gain(struct kt0913_device *radio, s32 gain)
> +{
> + switch (gain) {
> + case 6:
> + return regmap_update_bits(radio->regmap,
> + KT0913_REG_AMSYSCFG, KT0913_AMSYSCFG_AU_GAIN_MASK,
> + KT0913_AMSYSCFG_AU_GAIN_6DB);
> + case 3:
> + return regmap_update_bits(radio->regmap,
> + KT0913_REG_AMSYSCFG, KT0913_AMSYSCFG_AU_GAIN_MASK,
> + KT0913_AMSYSCFG_AU_GAIN_3DB);
> + case 0:
> + return regmap_update_bits(radio->regmap,
> + KT0913_REG_AMSYSCFG, KT0913_AMSYSCFG_AU_GAIN_MASK,
> + KT0913_AMSYSCFG_AU_GAIN_0DB);
> + case -3:
> + return regmap_update_bits(radio->regmap,
> + KT0913_REG_AMSYSCFG, KT0913_AMSYSCFG_AU_GAIN_MASK,
> + KT0913_AMSYSCFG_AU_GAIN_MIN_3DB);
> + default:
> + return -EINVAL;
> + }
> +}
It's generally more legible to write this with an intermediate
variable holding the changed value. It's also most commonly
smaller object code.
static int __kt0913_set_au_gain(struct kt0913_device *radio, s32 gain)
{
int val;
switch (gain) {
case 6:
val = KT0913_AMSYSCFG_AU_GAIN_6DB;
break;
case 3:
val = KT0913_AMSYSCFG_AU_GAIN_3DB;
break;
case 0:
val = KT0913_AMSYSCFG_AU_GAIN_0DB;
break;
case -3:
val = KT0913_AMSYSCFG_AU_GAIN_MIN_3DB;
break;
default:
return -EINVAL;
}
return regmap_update_bits(radio->regmap, KT0913_REG_AMSYSCFG,
KT0913_AMSYSCFG_AU_GAIN_MASK, val);
}
