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-rw-r--r--sound/i2c/i2c.c326
1 files changed, 326 insertions, 0 deletions
diff --git a/sound/i2c/i2c.c b/sound/i2c/i2c.c
new file mode 100644
index 0000000000..847e3b6ca6
--- /dev/null
+++ b/sound/i2c/i2c.c
@@ -0,0 +1,326 @@
+// 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 const 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;
+ }
+ strscpy(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;
+ strscpy(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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 20:53:50 +0000