Hi,
On 17/11/2020 0.20, Viorel Suman (OSS) wrote:
From: Viorel Suman viorel.suman@nxp.com
Using GPIO API seems not a way to go for the case when the same reset GPIO is used to control several codecs. For a such case we can use the "gpio-reset" driver and the "shared" reset API to manage the reset GPIO - to deassert the reset when the first codec is powered up and assert it when there is no codec in use. DTS is supposed to look as follows:
/ { ak4458_reset: gpio-reset { compatible = "gpio-reset"; reset-gpios = <&pca6416 4 GPIO_ACTIVE_LOW>; #reset-cells = <0>; initially-in-reset;
I can not find anything resembling to this in next-20201119.
Where is the implementation and documentation for this gpio-reset?
};};
&i2c3 { pca6416: gpio@20 { compatible = "ti,tca6416"; reg = <0x20>; gpio-controller; #gpio-cells = <2>; };
ak4458_1: ak4458@10 { compatible = "asahi-kasei,ak4458"; reg = <0x10>; resets = <&ak4458_reset>; }; ak4458_2: ak4458@11 { compatible = "asahi-kasei,ak4458"; reg = <0x11>; resets = <&ak4458_reset>; }; ak4458_3: ak4458@12 { compatible = "asahi-kasei,ak4458"; reg = <0x12>; resets = <&ak4458_reset>; };};
Signed-off-by: Viorel Suman viorel.suman@nxp.com
sound/soc/codecs/ak4458.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-)
diff --git a/sound/soc/codecs/ak4458.c b/sound/soc/codecs/ak4458.c index 1010c9ee2e83..f27727cb1382 100644 --- a/sound/soc/codecs/ak4458.c +++ b/sound/soc/codecs/ak4458.c @@ -13,6 +13,7 @@ #include <linux/of_gpio.h> #include <linux/pm_runtime.h> #include <linux/regulator/consumer.h> +#include <linux/reset.h> #include <linux/slab.h> #include <sound/initval.h> #include <sound/pcm_params.h> @@ -45,7 +46,7 @@ struct ak4458_priv { const struct ak4458_drvdata *drvdata; struct device *dev; struct regmap *regmap;
- struct gpio_desc *reset_gpiod;
- struct reset_control *reset; struct gpio_desc *mute_gpiod; int digfil; /* SSLOW, SD, SLOW bits */ int fs; /* sampling rate */
@@ -597,17 +598,17 @@ static struct snd_soc_dai_driver ak4497_dai = {
static void ak4458_power_off(struct ak4458_priv *ak4458) {
- if (ak4458->reset_gpiod) {
gpiod_set_value_cansleep(ak4458->reset_gpiod, 0);usleep_range(1000, 2000);
- if (ak4458->reset) {
reset_control_assert(ak4458->reset);msleep(20);}
static void ak4458_power_on(struct ak4458_priv *ak4458) {
- if (ak4458->reset_gpiod) {
gpiod_set_value_cansleep(ak4458->reset_gpiod, 1);usleep_range(1000, 2000);
- if (ak4458->reset) {
reset_control_deassert(ak4458->reset);msleep(20);}
@@ -685,7 +686,6 @@ static int __maybe_unused ak4458_runtime_resume(struct device *dev) if (ak4458->mute_gpiod) gpiod_set_value_cansleep(ak4458->mute_gpiod, 1);
ak4458_power_off(ak4458); ak4458_power_on(ak4458);
regcache_cache_only(ak4458->regmap, false);
@@ -771,10 +771,9 @@ static int ak4458_i2c_probe(struct i2c_client *i2c)
ak4458->drvdata = of_device_get_match_data(&i2c->dev);
- ak4458->reset_gpiod = devm_gpiod_get_optional(ak4458->dev, "reset",
GPIOD_OUT_LOW);- if (IS_ERR(ak4458->reset_gpiod))
return PTR_ERR(ak4458->reset_gpiod);
- ak4458->reset = devm_reset_control_get_optional_shared(ak4458->dev, NULL);
- if (IS_ERR(ak4458->reset))
return PTR_ERR(ak4458->reset);
The binding documentation must be updated and you must support the gpio way as well.
When I had this discussion around using the reset framework for shared enable and/or reset pins it was suggested that _if_ such a driver makes sense then it should internally handle (by using magic strings) the fallback and work with pre-reset binding.
ak4458->mute_gpiod = devm_gpiod_get_optional(ak4458->dev, "mute", GPIOD_OUT_LOW);
- Péter
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