ucontrol

= (struct Soc_enum *) kcontrol->private_value; Uinfo->type = sndrv_ctl_elem_type_enumerated; Uinfo->count = e->shift_l = = E->shift_r? 1:2; Uinfo->value.enumerated.items = e->max; if (Uinfo->value.enumerated.item > e->max-1) uinfo->value.enumerated.item = e->max-1; strcpy (Uinfo->value.enumerated.name, E->texts[uinfo->value.enumerated.item]); return 0; } is to get some of the kcontrol->private_value parameters. int snd_soc_get_enum_double (struct Snd_k

*uinfo) { static char *texts[4] = { "First", "Second", "third", "fourth" }; Uinfo->type = sndrv_ctl_elem_type_enumerated; Uinfo->count = 1; Uinfo->value.enumerated.items = 4; if (Uinfo->value.enumerated.item > 3) Uinfo->value.enumerated.item = 3; strcpy (Uinfo->value.enumerated.name, Texts[uinfo->value.enumerated.item]); return 0; } ALSA has implemented some common info callback functions for us, such as Snd_ctl_boolean_mono_info (), Snd_ctl_boolean_stereo_info (

Snd_ctl_elem_value *ucontrol){struct Rk616_codec_priv *rk616 = Rk616_priv;long int pre_path;if (!rk616) {PRINTK ("%s:rk616_priv is null\n", __func__);Return-einval;}if (Rk616->capture_path = = Ucontrol->value.integer.value[0]) {DBG ("%s:capture_path is not changed!\n", __func__);return 0;}Pre_path = rk616->capture_path;Rk616->capture_path = ucontrol->value.integ

drive to analyze. Device resources: You can see that the Speak and handphone GPIO are given the Rk30_pin2_pd7 . static struct Rk616_platform_data Rk616_pdata = {. Power_init = Rk616_power_on_init,. Power_deinit = Rk616_power_deinit,. scl_rate = Rk616_scl_rate,. Lcd0_func = input,//port lcd0 as input. Lcd1_func = input,//port lcd1 as input. LVDS_CH_NR = 1,//the number of used LVDS channel. HDMI_IRQ = Rk30_pin2_pd6,. Spk_ctl_gpio = Rk30_pin2_pd7 ,. Hp_ctl_gpio = Rk30_pin2_pd7 ,};Functions for c

, . Power_deinit = rk616_power_deinit, . Scl_rate = RK616_SCL_RATE, . Lcd0_func = INPUT, // port lcd0 as input . Lcd1_func = INPUT, // port lcd1 as input . Lvds_ch_nr = 1, // the number of used lvds channel . Hdmi_irq = RK30_PIN2_PD6, . Spk_ctl_gpio = RK30_PIN2_PD7, . Hp_ctl_gpio = RK30_PIN2_PD7, }; Function for controlling the audio output channel in the device driver: Static int rk616_playback_path_put (struct snd_kcontrol * kcontrol, Struct snd_ctl_elem_value *

switched normally, it means that the upper layer has already called the corresponding interface. From the drive to analyze. Equipment resources: Can see Speak and handphone of the Enable GPIO all give is Rk30_pin2_pd7 . static struct Rk616_platform_data Rk616_pdata = {. Power_init = Rk616_power_on_init,. Power_deinit = Rk616_power_deinit,. scl_rate = Rk616_scl_rate,. Lcd0_func = input,//port lcd0 as input. Lcd1_func = input,//port lcd1 as input. LVDS_CH_NR = 1,//the number of used LVDS channel

Then, the get callback function can be implemented as follows: Static int snd_sbmixer_get_single (struct snd_kcontrol * kcontrol,Struct snd_ctl_elem_value * ucontrol) {Int Reg = kcontrol-> private_value 0xff;Int shift = (kcontrol-> private_value> 16) 0xff;Int mask = (kcontrol-> private_value> 24) 0xff;.... // Read the value of the corresponding register based on the above values and fill in the value} If the Count field of control is greater th

corresponding register, the displacement value, the maximum value, and whether it is logically reversed, and the control's put callback function and get callback function need to use this structure to access the actual registers. Let's look at the definition of the get callback function:[CPP] View Plain copy INTNBSP;SND_SOC_GET_VOLSW (structsnd_kcontrol*kcontrol, structsnd_ctl_elem_value*ucontrol) { structsoc_mixer_control*mc= (structsoc_ mixer_