diff options
| -rw-r--r-- | sound/soc/codecs/cs4270.c | 58 |
1 files changed, 57 insertions, 1 deletions
diff --git a/sound/soc/codecs/cs4270.c b/sound/soc/codecs/cs4270.c index 153124b2e3b1..a32b8226c8a4 100644 --- a/sound/soc/codecs/cs4270.c +++ b/sound/soc/codecs/cs4270.c @@ -18,7 +18,7 @@ * - The machine driver's 'startup' function must call * cs4270_set_dai_sysclk() with the value of MCLK. * - Only I2S and left-justified modes are supported - * - Power management is not supported + * - Power management is supported */ #include <linux/module.h> @@ -27,6 +27,7 @@ #include <sound/soc.h> #include <sound/initval.h> #include <linux/i2c.h> +#include <linux/delay.h> #include "cs4270.h" @@ -65,6 +66,8 @@ #define CS4270_PWRCTL_PDN_ADC 0x20 #define CS4270_PWRCTL_PDN_DAC 0x02 #define CS4270_PWRCTL_PDN 0x01 +#define CS4270_PWRCTL_PDN_ALL \ + (CS4270_PWRCTL_PDN_ADC | CS4270_PWRCTL_PDN_DAC | CS4270_PWRCTL_PDN) #define CS4270_MODE_SPEED_MASK 0x30 #define CS4270_MODE_1X 0x00 #define CS4270_MODE_2X 0x10 @@ -788,6 +791,57 @@ static struct i2c_device_id cs4270_id[] = { }; MODULE_DEVICE_TABLE(i2c, cs4270_id); +#ifdef CONFIG_PM + +/* This suspend/resume implementation can handle both - a simple standby + * where the codec remains powered, and a full suspend, where the voltage + * domain the codec is connected to is teared down and/or any other hardware + * reset condition is asserted. + * + * The codec's own power saving features are enabled in the suspend callback, + * and all registers are written back to the hardware when resuming. + */ + +static int cs4270_i2c_suspend(struct i2c_client *client, pm_message_t mesg) +{ + struct cs4270_private *cs4270 = i2c_get_clientdata(client); + struct snd_soc_codec *codec = &cs4270->codec; + int reg = snd_soc_read(codec, CS4270_PWRCTL) | CS4270_PWRCTL_PDN_ALL; + + return snd_soc_write(codec, CS4270_PWRCTL, reg); +} + +static int cs4270_i2c_resume(struct i2c_client *client) +{ + struct cs4270_private *cs4270 = i2c_get_clientdata(client); + struct snd_soc_codec *codec = &cs4270->codec; + int reg; + + /* In case the device was put to hard reset during sleep, we need to + * wait 500ns here before any I2C communication. */ + ndelay(500); + + /* first restore the entire register cache ... */ + for (reg = CS4270_FIRSTREG; reg <= CS4270_LASTREG; reg++) { + u8 val = snd_soc_read(codec, reg); + + if (i2c_smbus_write_byte_data(client, reg, val)) { + dev_err(codec->dev, "i2c write failed\n"); + return -EIO; + } + } + + /* ... then disable the power-down bits */ + reg = snd_soc_read(codec, CS4270_PWRCTL); + reg &= ~CS4270_PWRCTL_PDN_ALL; + + return snd_soc_write(codec, CS4270_PWRCTL, reg); +} +#else +#define cs4270_i2c_suspend NULL +#define cs4270_i2c_resume NULL +#endif /* CONFIG_PM */ + /* * cs4270_i2c_driver - I2C device identification * @@ -802,6 +856,8 @@ static struct i2c_driver cs4270_i2c_driver = { .id_table = cs4270_id, .probe = cs4270_i2c_probe, .remove = cs4270_i2c_remove, + .suspend = cs4270_i2c_suspend, + .resume = cs4270_i2c_resume, }; /* |