334 lines
8.1 KiB
C
334 lines
8.1 KiB
C
/*
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* Generic i2c interface for ALSA
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*
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* (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
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* Modified for the ALSA driver by Jaroslav Kysela <perex@suse.cz>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <sound/driver.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <sound/core.h>
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#include <sound/i2c.h>
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MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
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MODULE_DESCRIPTION("Generic i2c interface for ALSA");
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MODULE_LICENSE("GPL");
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static int snd_i2c_bit_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count);
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static int snd_i2c_bit_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count);
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static int snd_i2c_bit_probeaddr(snd_i2c_bus_t *bus, unsigned short addr);
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static snd_i2c_ops_t snd_i2c_bit_ops = {
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.sendbytes = snd_i2c_bit_sendbytes,
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.readbytes = snd_i2c_bit_readbytes,
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.probeaddr = snd_i2c_bit_probeaddr,
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};
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static int snd_i2c_bus_free(snd_i2c_bus_t *bus)
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{
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snd_i2c_bus_t *slave;
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snd_i2c_device_t *device;
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snd_assert(bus != NULL, return -EINVAL);
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while (!list_empty(&bus->devices)) {
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device = snd_i2c_device(bus->devices.next);
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snd_i2c_device_free(device);
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}
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if (bus->master)
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list_del(&bus->buses);
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else {
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while (!list_empty(&bus->buses)) {
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slave = snd_i2c_slave_bus(bus->buses.next);
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snd_device_free(bus->card, slave);
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}
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}
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if (bus->private_free)
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bus->private_free(bus);
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kfree(bus);
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return 0;
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}
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static int snd_i2c_bus_dev_free(snd_device_t *device)
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{
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snd_i2c_bus_t *bus = device->device_data;
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return snd_i2c_bus_free(bus);
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}
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int snd_i2c_bus_create(snd_card_t *card, const char *name, snd_i2c_bus_t *master, snd_i2c_bus_t **ri2c)
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{
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snd_i2c_bus_t *bus;
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int err;
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static snd_device_ops_t ops = {
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.dev_free = snd_i2c_bus_dev_free,
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};
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*ri2c = NULL;
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bus = kzalloc(sizeof(*bus), GFP_KERNEL);
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if (bus == NULL)
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return -ENOMEM;
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init_MUTEX(&bus->lock_mutex);
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INIT_LIST_HEAD(&bus->devices);
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INIT_LIST_HEAD(&bus->buses);
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bus->card = card;
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bus->ops = &snd_i2c_bit_ops;
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if (master) {
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list_add_tail(&bus->buses, &master->buses);
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bus->master = master;
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}
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strlcpy(bus->name, name, sizeof(bus->name));
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if ((err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops)) < 0) {
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snd_i2c_bus_free(bus);
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return err;
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}
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*ri2c = bus;
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return 0;
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}
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int snd_i2c_device_create(snd_i2c_bus_t *bus, const char *name, unsigned char addr, snd_i2c_device_t **rdevice)
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{
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snd_i2c_device_t *device;
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*rdevice = NULL;
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snd_assert(bus != NULL, return -EINVAL);
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device = kzalloc(sizeof(*device), GFP_KERNEL);
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if (device == NULL)
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return -ENOMEM;
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device->addr = addr;
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strlcpy(device->name, name, sizeof(device->name));
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list_add_tail(&device->list, &bus->devices);
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device->bus = bus;
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*rdevice = device;
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return 0;
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}
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int snd_i2c_device_free(snd_i2c_device_t *device)
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{
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if (device->bus)
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list_del(&device->list);
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if (device->private_free)
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device->private_free(device);
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kfree(device);
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return 0;
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}
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int snd_i2c_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
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{
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return device->bus->ops->sendbytes(device, bytes, count);
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}
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int snd_i2c_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
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{
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return device->bus->ops->readbytes(device, bytes, count);
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}
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int snd_i2c_probeaddr(snd_i2c_bus_t *bus, unsigned short addr)
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{
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return bus->ops->probeaddr(bus, addr);
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}
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/*
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* bit-operations
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*/
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static inline void snd_i2c_bit_hw_start(snd_i2c_bus_t *bus)
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{
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if (bus->hw_ops.bit->start)
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bus->hw_ops.bit->start(bus);
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}
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static inline void snd_i2c_bit_hw_stop(snd_i2c_bus_t *bus)
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{
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if (bus->hw_ops.bit->stop)
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bus->hw_ops.bit->stop(bus);
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}
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static void snd_i2c_bit_direction(snd_i2c_bus_t *bus, int clock, int data)
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{
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if (bus->hw_ops.bit->direction)
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bus->hw_ops.bit->direction(bus, clock, data);
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}
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static void snd_i2c_bit_set(snd_i2c_bus_t *bus, int clock, int data)
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{
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bus->hw_ops.bit->setlines(bus, clock, data);
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}
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#if 0
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static int snd_i2c_bit_clock(snd_i2c_bus_t *bus)
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{
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if (bus->hw_ops.bit->getclock)
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return bus->hw_ops.bit->getclock(bus);
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return -ENXIO;
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}
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#endif
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static int snd_i2c_bit_data(snd_i2c_bus_t *bus, int ack)
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{
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return bus->hw_ops.bit->getdata(bus, ack);
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}
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static void snd_i2c_bit_start(snd_i2c_bus_t *bus)
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{
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snd_i2c_bit_hw_start(bus);
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snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
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snd_i2c_bit_set(bus, 1, 1);
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snd_i2c_bit_set(bus, 1, 0);
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snd_i2c_bit_set(bus, 0, 0);
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}
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static void snd_i2c_bit_stop(snd_i2c_bus_t *bus)
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{
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snd_i2c_bit_set(bus, 0, 0);
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snd_i2c_bit_set(bus, 1, 0);
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snd_i2c_bit_set(bus, 1, 1);
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snd_i2c_bit_hw_stop(bus);
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}
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static void snd_i2c_bit_send(snd_i2c_bus_t *bus, int data)
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{
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snd_i2c_bit_set(bus, 0, data);
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snd_i2c_bit_set(bus, 1, data);
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snd_i2c_bit_set(bus, 0, data);
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}
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static int snd_i2c_bit_ack(snd_i2c_bus_t *bus)
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{
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int ack;
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snd_i2c_bit_set(bus, 0, 1);
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snd_i2c_bit_set(bus, 1, 1);
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snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
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ack = snd_i2c_bit_data(bus, 1);
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snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
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snd_i2c_bit_set(bus, 0, 1);
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return ack ? -EIO : 0;
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}
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static int snd_i2c_bit_sendbyte(snd_i2c_bus_t *bus, unsigned char data)
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{
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int i, err;
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for (i = 7; i >= 0; i--)
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snd_i2c_bit_send(bus, !!(data & (1 << i)));
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if ((err = snd_i2c_bit_ack(bus)) < 0)
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return err;
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return 0;
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}
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static int snd_i2c_bit_readbyte(snd_i2c_bus_t *bus, int last)
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{
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int i;
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unsigned char data = 0;
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snd_i2c_bit_set(bus, 0, 1);
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snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
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for (i = 7; i >= 0; i--) {
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snd_i2c_bit_set(bus, 1, 1);
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if (snd_i2c_bit_data(bus, 0))
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data |= (1 << i);
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snd_i2c_bit_set(bus, 0, 1);
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}
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snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
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snd_i2c_bit_send(bus, !!last);
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return data;
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}
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static int snd_i2c_bit_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
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{
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snd_i2c_bus_t *bus = device->bus;
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int err, res = 0;
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if (device->flags & SND_I2C_DEVICE_ADDRTEN)
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return -EIO; /* not yet implemented */
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snd_i2c_bit_start(bus);
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if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
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snd_i2c_bit_hw_stop(bus);
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return err;
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}
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while (count-- > 0) {
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if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
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snd_i2c_bit_hw_stop(bus);
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return err;
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}
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res++;
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}
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snd_i2c_bit_stop(bus);
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return res;
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}
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static int snd_i2c_bit_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
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{
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snd_i2c_bus_t *bus = device->bus;
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int err, res = 0;
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if (device->flags & SND_I2C_DEVICE_ADDRTEN)
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return -EIO; /* not yet implemented */
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snd_i2c_bit_start(bus);
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if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) {
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snd_i2c_bit_hw_stop(bus);
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return err;
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}
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while (count-- > 0) {
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if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
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snd_i2c_bit_hw_stop(bus);
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return err;
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}
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*bytes++ = (unsigned char)err;
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res++;
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}
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snd_i2c_bit_stop(bus);
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return res;
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}
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static int snd_i2c_bit_probeaddr(snd_i2c_bus_t *bus, unsigned short addr)
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{
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int err;
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if (addr & 0x8000) /* 10-bit address */
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return -EIO; /* not yet implemented */
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if (addr & 0x7f80) /* invalid address */
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return -EINVAL;
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snd_i2c_bit_start(bus);
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err = snd_i2c_bit_sendbyte(bus, addr << 1);
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snd_i2c_bit_stop(bus);
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return err;
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}
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EXPORT_SYMBOL(snd_i2c_bus_create);
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EXPORT_SYMBOL(snd_i2c_device_create);
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EXPORT_SYMBOL(snd_i2c_device_free);
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EXPORT_SYMBOL(snd_i2c_sendbytes);
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EXPORT_SYMBOL(snd_i2c_readbytes);
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EXPORT_SYMBOL(snd_i2c_probeaddr);
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static int __init alsa_i2c_init(void)
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{
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return 0;
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}
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static void __exit alsa_i2c_exit(void)
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{
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}
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module_init(alsa_i2c_init)
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module_exit(alsa_i2c_exit)
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