Messages in this thread | | | Subject | Re: [alsa-devel] [PATCH 2/2] ASoC: max98927: Add reset-gpio support | From | Rohit Kumar <> | Date | Wed, 12 Sep 2018 22:17:24 +0530 |
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On 9/12/2018 5:49 PM, Cheng-Yi Chiang wrote: > Toggle reset line in max98927_i2c_probe. > Use a list to store max98927 instances so we do not toggle reset line > again if more than one instances share the same reset line. > > Signed-off-by: Cheng-Yi Chiang <cychiang@chromium.org> Reviewed-and-tested-by: Rohit kumar <rohitkr@codeaurora.org>
> --- > sound/soc/codecs/max98927.c | 78 +++++++++++++++++++++++++++++++++++++++++++++ > sound/soc/codecs/max98927.h | 2 ++ > 2 files changed, 80 insertions(+) > > diff --git a/sound/soc/codecs/max98927.c b/sound/soc/codecs/max98927.c > index 941712058a8f5..789b27cdfd9e0 100644 > --- a/sound/soc/codecs/max98927.c > +++ b/sound/soc/codecs/max98927.c > @@ -11,6 +11,7 @@ > */ > > #include <linux/acpi.h> > +#include <linux/delay.h> > #include <linux/i2c.h> > #include <linux/module.h> > #include <linux/regmap.h> > @@ -24,6 +25,11 @@ > #include <sound/tlv.h> > #include "max98927.h" > > +#define MAX98927_MIN_RESET_US 1 > +#define MAX98927_RELEASE_RESET_DELAY_US 500 > + > +static LIST_HEAD(reset_list); > + > static struct reg_default max98927_reg[] = { > {MAX98927_R0001_INT_RAW1, 0x00}, > {MAX98927_R0002_INT_RAW2, 0x00}, > @@ -877,6 +883,54 @@ static void max98927_slot_config(struct i2c_client *i2c, > max98927->i_l_slot = 1; > } > > +static int max98927_i2c_toggle_reset(struct device *dev, > + struct max98927_priv *max98927) > +{ > + /* > + * If we do not have reset gpio, assume platform firmware > + * controls the regulator and toggles it for us. > + */ > + if (!max98927->reset_gpio) > + return 0; > + > + gpiod_set_value_cansleep(max98927->reset_gpio, 1); > + > + /* > + * We need to wait a bit before we are allowed to release reset GPIO. > + */ > + usleep_range(MAX98927_MIN_RESET_US, MAX98927_MIN_RESET_US + 5); > + > + gpiod_set_value_cansleep(max98927->reset_gpio, 0); > + > + /* > + * We need to wait a bit before I2C communication is available. > + */ > + usleep_range(MAX98927_RELEASE_RESET_DELAY_US, > + MAX98927_RELEASE_RESET_DELAY_US + 5); > + > + /* > + * Release reset GPIO because we are not going to use it. > + */ > + devm_gpiod_put(dev, max98927->reset_gpio); > + > + return 0; > +} > + > +static bool max98927_is_first_to_reset(struct max98927_priv *max98927) > +{ > + struct max98927_priv *p; > + > + if (!max98927->reset_gpio) > + return false; > + > + list_for_each_entry(p, &reset_list, list) { > + if (max98927->reset_gpio == p->reset_gpio) > + return false; > + } > + > + return true; > +} > + > static int max98927_i2c_probe(struct i2c_client *i2c, > const struct i2c_device_id *id) > { > @@ -904,6 +958,28 @@ static int max98927_i2c_probe(struct i2c_client *i2c, > } else > max98927->interleave_mode = 0; > > + /* Gets optional GPIO for reset line. */ > + max98927->reset_gpio = devm_gpiod_get_optional( > + &i2c->dev, "reset", GPIOD_OUT_LOW); > + if (IS_ERR(max98927->reset_gpio)) { > + ret = PTR_ERR(max98927->reset_gpio); > + dev_err(&i2c->dev, "error getting reset gpio: %d\n", ret); > + return ret; > + } > + > + /* > + * Only toggle reset line for the first instance when the > + * reset line is shared among instances. For example, > + * left and right amplifier share the same reset line, and > + * we should only toggle the reset line once. > + */ > + if (max98927_is_first_to_reset(max98927)) { > + dev_info(&i2c->dev, "%s: toggle reset line\n", __func__); > + ret = max98927_i2c_toggle_reset(&i2c->dev, max98927); > + if (ret) > + return ret; > + } > + > /* regmap initialization */ > max98927->regmap > = devm_regmap_init_i2c(i2c, &max98927_regmap); > @@ -934,6 +1010,8 @@ static int max98927_i2c_probe(struct i2c_client *i2c, > if (ret < 0) > dev_err(&i2c->dev, "Failed to register component: %d\n", ret); > > + list_add(&max98927->list, &reset_list); > + > return ret; > } > > diff --git a/sound/soc/codecs/max98927.h b/sound/soc/codecs/max98927.h > index 538992a238b28..d48f61f6c3ba5 100644 > --- a/sound/soc/codecs/max98927.h > +++ b/sound/soc/codecs/max98927.h > @@ -275,5 +275,7 @@ struct max98927_priv { > unsigned int master; > unsigned int digital_gain; > bool tdm_mode; > + struct gpio_desc *reset_gpio; > + struct list_head list; > }; > #endif
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