Re: [PATCH v2 3/3] ASoC: Intel: bytcr_rt5651: Add support for externar amplifier enable GPIO

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 7/1/18 1:36 PM, Hans de Goede wrote:
> The rt5651 does not have a built-in speaker amplifier, so it is often
> used together with an external amplifier. On Cherry Trail boards this
> external amplifier's enable pin is driven through a GPIO, which is
> given as the first GPIO in the ACPI resources of the codec fwnode.
> 
> This commit adds support to the bytcr_rt5651 for this GPIO, fixing
> the speaker not working on CHT devices with a rt5651 codec.

ALl this GPIO/ACPI stuff is a bit beyond my understanding. My only 
comment is "how would this work on Baytrail"? There are clearly a set of 
devices which use the SSP0 routing - so Baytrail-CR packages, it's not 
clear to me how the amplifier is controlled in those cases?

> 
> Cc: Carlo Caione <carlo@endlessm.com>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> Changes in v2:
> -Handle the ext amp GPIO entirely in the machine driver, the ext-amp is
>   not part of the codec, so it should not be controlled by the codec driver
> ---
>   sound/soc/intel/boards/bytcr_rt5651.c | 65 +++++++++++++++++++++++++--
>   1 file changed, 62 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/soc/intel/boards/bytcr_rt5651.c b/sound/soc/intel/boards/bytcr_rt5651.c
> index d920725ce603..5301205496be 100644
> --- a/sound/soc/intel/boards/bytcr_rt5651.c
> +++ b/sound/soc/intel/boards/bytcr_rt5651.c
> @@ -26,6 +26,8 @@
>   #include <linux/clk.h>
>   #include <linux/device.h>
>   #include <linux/dmi.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/gpio/machine.h>
>   #include <linux/slab.h>
>   #include <asm/cpu_device_id.h>
>   #include <asm/intel-family.h>
> @@ -86,6 +88,7 @@ enum {
>   
>   struct byt_rt5651_private {
>   	struct clk *mclk;
> +	struct gpio_desc *ext_amp_gpio;
>   	struct snd_soc_jack jack;
>   };
>   
> @@ -208,6 +211,20 @@ static int platform_clock_control(struct snd_soc_dapm_widget *w,
>   	return 0;
>   }
>   
> +static int rt5651_ext_amp_power_event(struct snd_soc_dapm_widget *w,
> +	struct snd_kcontrol *kcontrol, int event)
> +{
> +	struct snd_soc_card *card = w->dapm->card;
> +	struct byt_rt5651_private *priv = snd_soc_card_get_drvdata(card);
> +
> +	if (SND_SOC_DAPM_EVENT_ON(event))
> +		gpiod_set_value_cansleep(priv->ext_amp_gpio, 1);
> +	else
> +		gpiod_set_value_cansleep(priv->ext_amp_gpio, 0);
> +
> +	return 0;
> +}
> +
>   static const struct snd_soc_dapm_widget byt_rt5651_widgets[] = {
>   	SND_SOC_DAPM_HP("Headphone", NULL),
>   	SND_SOC_DAPM_MIC("Headset Mic", NULL),
> @@ -217,7 +234,9 @@ static const struct snd_soc_dapm_widget byt_rt5651_widgets[] = {
>   	SND_SOC_DAPM_SUPPLY("Platform Clock", SND_SOC_NOPM, 0, 0,
>   			    platform_clock_control, SND_SOC_DAPM_PRE_PMU |
>   			    SND_SOC_DAPM_POST_PMD),
> -
> +	SND_SOC_DAPM_SUPPLY("Ext Amp Power", SND_SOC_NOPM, 0, 0,
> +			    rt5651_ext_amp_power_event,
> +			    SND_SOC_DAPM_PRE_PMD | SND_SOC_DAPM_POST_PMU),
>   };
>   
>   static const struct snd_soc_dapm_route byt_rt5651_audio_map[] = {
> @@ -225,6 +244,7 @@ static const struct snd_soc_dapm_route byt_rt5651_audio_map[] = {
>   	{"Headset Mic", NULL, "Platform Clock"},
>   	{"Internal Mic", NULL, "Platform Clock"},
>   	{"Speaker", NULL, "Platform Clock"},
> +	{"Speaker", NULL, "Ext Amp Power"},
>   	{"Line In", NULL, "Platform Clock"},
>   
>   	{"Headset Mic", NULL, "micbias1"}, /* lowercase for rt5651 */
> @@ -678,6 +698,18 @@ static const struct x86_cpu_id baytrail_cpu_ids[] = {
>   	{}
>   };
>   
> +static const struct x86_cpu_id cherrytrail_cpu_ids[] = {
> +	{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_AIRMONT },     /* Braswell */
> +	{}
> +};
> +
> +static const struct acpi_gpio_params ext_amp_enable_gpios = { 0, 0, false };
> +
> +static const struct acpi_gpio_mapping byt_rt5651_gpios[] = {
> +	{ "ext-amp-enable-gpios", &ext_amp_enable_gpios, 1 },
> +	{ },
> +};
> +
>   struct acpi_chan_package {   /* ACPICA seems to require 64 bit integers */
>   	u64 aif_value;       /* 1: AIF1, 2: AIF2 */
>   	u64 mclock_value;    /* usually 25MHz (0x17d7940), ignored */
> @@ -793,9 +825,36 @@ static int snd_byt_rt5651_mc_probe(struct platform_device *pdev)
>   
>   	/* Must be called before register_card, also see declaration comment. */
>   	ret_val = byt_rt5651_add_codec_device_props(codec_dev);
> -	put_device(codec_dev);
> -	if (ret_val)
> +	if (ret_val) {
> +		put_device(codec_dev);
>   		return ret_val;
> +	}
> +
> +	/* Cherry Trail devices use an external amplifier enable gpio */
> +	if (x86_match_cpu(cherrytrail_cpu_ids)) {
> +		devm_acpi_dev_add_driver_gpios(codec_dev, byt_rt5651_gpios);
> +		priv->ext_amp_gpio = devm_fwnode_get_index_gpiod_from_child(
> +						&pdev->dev, "ext-amp-enable", 0,
> +						codec_dev->fwnode,
> +						GPIOD_OUT_LOW, "speaker-amp");
> +		if (IS_ERR(priv->ext_amp_gpio)) {
> +			ret_val = PTR_ERR(priv->ext_amp_gpio);
> +			switch (ret_val) {
> +			case -ENOENT:
> +				priv->ext_amp_gpio = NULL;
> +				break;
> +			default:
> +				dev_err(&pdev->dev, "Failed to get ext-amp-enable GPIO: %d\n",
> +					ret_val);
> +				/* fall through */
> +			case -EPROBE_DEFER:
> +				put_device(codec_dev);
> +				return ret_val;
> +			}
> +		}
> +	}
> +
> +	put_device(codec_dev);
>   
>   	log_quirks(&pdev->dev);
>   
>