linux/sound/i2c/i2c.c
Thomas Gleixner 1a59d1b8e0 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:35 -07:00

327 lines
7.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Generic i2c interface for ALSA
*
* (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
* Modified for the ALSA driver by Jaroslav Kysela <perex@perex.cz>
*/
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <sound/core.h>
#include <sound/i2c.h>
MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
MODULE_DESCRIPTION("Generic i2c interface for ALSA");
MODULE_LICENSE("GPL");
static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
unsigned char *bytes, int count);
static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
unsigned char *bytes, int count);
static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
unsigned short addr);
static const struct snd_i2c_ops snd_i2c_bit_ops = {
.sendbytes = snd_i2c_bit_sendbytes,
.readbytes = snd_i2c_bit_readbytes,
.probeaddr = snd_i2c_bit_probeaddr,
};
static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
{
struct snd_i2c_bus *slave;
struct snd_i2c_device *device;
if (snd_BUG_ON(!bus))
return -EINVAL;
while (!list_empty(&bus->devices)) {
device = snd_i2c_device(bus->devices.next);
snd_i2c_device_free(device);
}
if (bus->master)
list_del(&bus->buses);
else {
while (!list_empty(&bus->buses)) {
slave = snd_i2c_slave_bus(bus->buses.next);
snd_device_free(bus->card, slave);
}
}
if (bus->private_free)
bus->private_free(bus);
kfree(bus);
return 0;
}
static int snd_i2c_bus_dev_free(struct snd_device *device)
{
struct snd_i2c_bus *bus = device->device_data;
return snd_i2c_bus_free(bus);
}
int snd_i2c_bus_create(struct snd_card *card, const char *name,
struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
{
struct snd_i2c_bus *bus;
int err;
static struct snd_device_ops ops = {
.dev_free = snd_i2c_bus_dev_free,
};
*ri2c = NULL;
bus = kzalloc(sizeof(*bus), GFP_KERNEL);
if (bus == NULL)
return -ENOMEM;
mutex_init(&bus->lock_mutex);
INIT_LIST_HEAD(&bus->devices);
INIT_LIST_HEAD(&bus->buses);
bus->card = card;
bus->ops = &snd_i2c_bit_ops;
if (master) {
list_add_tail(&bus->buses, &master->buses);
bus->master = master;
}
strlcpy(bus->name, name, sizeof(bus->name));
err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops);
if (err < 0) {
snd_i2c_bus_free(bus);
return err;
}
*ri2c = bus;
return 0;
}
EXPORT_SYMBOL(snd_i2c_bus_create);
int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
unsigned char addr, struct snd_i2c_device **rdevice)
{
struct snd_i2c_device *device;
*rdevice = NULL;
if (snd_BUG_ON(!bus))
return -EINVAL;
device = kzalloc(sizeof(*device), GFP_KERNEL);
if (device == NULL)
return -ENOMEM;
device->addr = addr;
strlcpy(device->name, name, sizeof(device->name));
list_add_tail(&device->list, &bus->devices);
device->bus = bus;
*rdevice = device;
return 0;
}
EXPORT_SYMBOL(snd_i2c_device_create);
int snd_i2c_device_free(struct snd_i2c_device *device)
{
if (device->bus)
list_del(&device->list);
if (device->private_free)
device->private_free(device);
kfree(device);
return 0;
}
EXPORT_SYMBOL(snd_i2c_device_free);
int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
{
return device->bus->ops->sendbytes(device, bytes, count);
}
EXPORT_SYMBOL(snd_i2c_sendbytes);
int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
{
return device->bus->ops->readbytes(device, bytes, count);
}
EXPORT_SYMBOL(snd_i2c_readbytes);
int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
{
return bus->ops->probeaddr(bus, addr);
}
EXPORT_SYMBOL(snd_i2c_probeaddr);
/*
* bit-operations
*/
static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
{
if (bus->hw_ops.bit->start)
bus->hw_ops.bit->start(bus);
}
static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
{
if (bus->hw_ops.bit->stop)
bus->hw_ops.bit->stop(bus);
}
static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
{
if (bus->hw_ops.bit->direction)
bus->hw_ops.bit->direction(bus, clock, data);
}
static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
{
bus->hw_ops.bit->setlines(bus, clock, data);
}
#if 0
static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
{
if (bus->hw_ops.bit->getclock)
return bus->hw_ops.bit->getclock(bus);
return -ENXIO;
}
#endif
static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
{
return bus->hw_ops.bit->getdata(bus, ack);
}
static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
{
snd_i2c_bit_hw_start(bus);
snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
snd_i2c_bit_set(bus, 1, 1);
snd_i2c_bit_set(bus, 1, 0);
snd_i2c_bit_set(bus, 0, 0);
}
static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
{
snd_i2c_bit_set(bus, 0, 0);
snd_i2c_bit_set(bus, 1, 0);
snd_i2c_bit_set(bus, 1, 1);
snd_i2c_bit_hw_stop(bus);
}
static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
{
snd_i2c_bit_set(bus, 0, data);
snd_i2c_bit_set(bus, 1, data);
snd_i2c_bit_set(bus, 0, data);
}
static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
{
int ack;
snd_i2c_bit_set(bus, 0, 1);
snd_i2c_bit_set(bus, 1, 1);
snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
ack = snd_i2c_bit_data(bus, 1);
snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
snd_i2c_bit_set(bus, 0, 1);
return ack ? -EIO : 0;
}
static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
{
int i, err;
for (i = 7; i >= 0; i--)
snd_i2c_bit_send(bus, !!(data & (1 << i)));
err = snd_i2c_bit_ack(bus);
if (err < 0)
return err;
return 0;
}
static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
{
int i;
unsigned char data = 0;
snd_i2c_bit_set(bus, 0, 1);
snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
for (i = 7; i >= 0; i--) {
snd_i2c_bit_set(bus, 1, 1);
if (snd_i2c_bit_data(bus, 0))
data |= (1 << i);
snd_i2c_bit_set(bus, 0, 1);
}
snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
snd_i2c_bit_send(bus, !!last);
return data;
}
static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
unsigned char *bytes, int count)
{
struct snd_i2c_bus *bus = device->bus;
int err, res = 0;
if (device->flags & SND_I2C_DEVICE_ADDRTEN)
return -EIO; /* not yet implemented */
snd_i2c_bit_start(bus);
err = snd_i2c_bit_sendbyte(bus, device->addr << 1);
if (err < 0) {
snd_i2c_bit_hw_stop(bus);
return err;
}
while (count-- > 0) {
err = snd_i2c_bit_sendbyte(bus, *bytes++);
if (err < 0) {
snd_i2c_bit_hw_stop(bus);
return err;
}
res++;
}
snd_i2c_bit_stop(bus);
return res;
}
static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
unsigned char *bytes, int count)
{
struct snd_i2c_bus *bus = device->bus;
int err, res = 0;
if (device->flags & SND_I2C_DEVICE_ADDRTEN)
return -EIO; /* not yet implemented */
snd_i2c_bit_start(bus);
err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1);
if (err < 0) {
snd_i2c_bit_hw_stop(bus);
return err;
}
while (count-- > 0) {
err = snd_i2c_bit_readbyte(bus, count == 0);
if (err < 0) {
snd_i2c_bit_hw_stop(bus);
return err;
}
*bytes++ = (unsigned char)err;
res++;
}
snd_i2c_bit_stop(bus);
return res;
}
static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
{
int err;
if (addr & 0x8000) /* 10-bit address */
return -EIO; /* not yet implemented */
if (addr & 0x7f80) /* invalid address */
return -EINVAL;
snd_i2c_bit_start(bus);
err = snd_i2c_bit_sendbyte(bus, addr << 1);
snd_i2c_bit_stop(bus);
return err;
}