drivers/media/usb/stk1160/stk1160-ac97.c

   1 /*
   2  * STK1160 driver
   3  *
   4  * Copyright (C) 2012 Ezequiel Garcia
   5  * <elezegarcia--a.t--gmail.com>
   6  *
   7  * Based on Easycap driver by R.M. Thomas
   8  *      Copyright (C) 2010 R.M. Thomas
   9  *      <rmthomas--a.t--sciolus.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  */
  22
  23 #include <linux/module.h>
  24 #include <sound/core.h>
  25 #include <sound/initval.h>
  26 #include <sound/ac97_codec.h>
  27
  28 #include "stk1160.h"
  29 #include "stk1160-reg.h"
  30
  31 static struct snd_ac97 *stk1160_ac97;
  32
  33 static void stk1160_write_ac97(struct snd_ac97 *ac97, u16 reg, u16 value)
  34 {
  35         struct stk1160 *dev = ac97->private_data;
  36
  37         /* Set codec register address */
  38         stk1160_write_reg(dev, STK1160_AC97_ADDR, reg);
  39
  40         /* Set codec command */
  41         stk1160_write_reg(dev, STK1160_AC97_CMD, value & 0xff);
  42         stk1160_write_reg(dev, STK1160_AC97_CMD + 1, (value & 0xff00) >> 8);
  43
  44         /*
  45          * Set command write bit to initiate write operation.
  46          * The bit will be cleared when transfer is done.
  47          */
  48         stk1160_write_reg(dev, STK1160_AC97CTL_0, 0x8c);
  49 }
  50
  51 static u16 stk1160_read_ac97(struct snd_ac97 *ac97, u16 reg)
  52 {
  53         struct stk1160 *dev = ac97->private_data;
  54         u8 vall = 0;
  55         u8 valh = 0;
  56
  57         /* Set codec register address */
  58         stk1160_write_reg(dev, STK1160_AC97_ADDR, reg);
  59
  60         /*
  61          * Set command read bit to initiate read operation.
  62          * The bit will be cleared when transfer is done.
  63          */
  64         stk1160_write_reg(dev, STK1160_AC97CTL_0, 0x8b);
  65
  66         /* Retrieve register value */
  67         stk1160_read_reg(dev, STK1160_AC97_CMD, &vall);
  68         stk1160_read_reg(dev, STK1160_AC97_CMD + 1, &valh);
  69
  70         return (valh << 8) | vall;
  71 }
  72
  73 static void stk1160_reset_ac97(struct snd_ac97 *ac97)
  74 {
  75         struct stk1160 *dev = ac97->private_data;
  76         /* Two-step reset AC97 interface and hardware codec */
  77         stk1160_write_reg(dev, STK1160_AC97CTL_0, 0x94);
  78         stk1160_write_reg(dev, STK1160_AC97CTL_0, 0x88);
  79
  80         /* Set 16-bit audio data and choose L&R channel*/
  81         stk1160_write_reg(dev, STK1160_AC97CTL_1 + 2, 0x01);
  82 }
  83
  84 static struct snd_ac97_bus_ops stk1160_ac97_ops = {
  85         .read   = stk1160_read_ac97,
  86         .write  = stk1160_write_ac97,
  87         .reset  = stk1160_reset_ac97,
  88 };
  89
  90 int stk1160_ac97_register(struct stk1160 *dev)
  91 {
  92         struct snd_card *card = NULL;
  93         struct snd_ac97_bus *ac97_bus;
  94         struct snd_ac97_template ac97_template;
  95         int rc;
  96
  97         /*
  98          * Just want a card to access ac96 controls,
  99          * the actual capture interface will be handled by snd-usb-audio
 100          */
 101         rc = snd_card_create(SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
 102                               THIS_MODULE, 0, &card);
 103         if (rc < 0)
 104                 return rc;
 105
 106         snd_card_set_dev(card, dev->dev);
 107
 108         /* TODO: I'm not sure where should I get these names :-( */
 109         snprintf(card->shortname, sizeof(card->shortname),
 110                  "stk1160-mixer");
 111         snprintf(card->longname, sizeof(card->longname),
 112                  "stk1160 ac97 codec mixer control");
 113         strncpy(card->driver, dev->dev->driver->name, sizeof(card->driver));
 114
 115         rc = snd_ac97_bus(card, 0, &stk1160_ac97_ops, NULL, &ac97_bus);
 116         if (rc)
 117                 goto err;
 118
 119         /* We must set private_data before calling snd_ac97_mixer */
 120         memset(&ac97_template, 0, sizeof(ac97_template));
 121         ac97_template.private_data = dev;
 122         ac97_template.scaps = AC97_SCAP_SKIP_MODEM;
 123         rc = snd_ac97_mixer(ac97_bus, &ac97_template, &stk1160_ac97);
 124         if (rc)
 125                 goto err;
 126
 127         dev->snd_card = card;
 128         rc = snd_card_register(card);
 129         if (rc)
 130                 goto err;
 131
 132         return 0;
 133
 134 err:
 135         dev->snd_card = NULL;
 136         snd_card_free(card);
 137         return rc;
 138 }
 139
 140 int stk1160_ac97_unregister(struct stk1160 *dev)
 141 {
 142         struct snd_card *card = dev->snd_card;
 143
 144         /*
 145          * We need to check usb_device,
 146          * because ac97 release attempts to communicate with codec
 147          */
 148         if (card && dev->udev)
 149                 snd_card_free(card);
 150
 151         return 0;
 152 }