u-boot/drivers/i2c/i2c-uclass.c
Simon Glass c6202d857e dm: i2c: Add a uclass for I2C
The uclass implements the same operations as the current I2C framework but
makes some changes to make it fit driver model better:

- Remove the chip address from API calls
- Remove the address length from API calls
- Remove concept of 'current' I2C bus
- Drop all existing init functions

Acked-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
2014-12-11 13:18:42 -07:00

466 lines
11 KiB
C

/*
* Copyright (c) 2014 Google, Inc
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <fdtdec.h>
#include <i2c.h>
#include <malloc.h>
#include <dm/device-internal.h>
#include <dm/lists.h>
#include <dm/root.h>
DECLARE_GLOBAL_DATA_PTR;
#define I2C_MAX_OFFSET_LEN 4
/**
* i2c_setup_offset() - Set up a new message with a chip offset
*
* @chip: Chip to use
* @offset: Byte offset within chip
* @offset_buf: Place to put byte offset
* @msg: Message buffer
* @return 0 if OK, -EADDRNOTAVAIL if the offset length is 0. In that case the
* message is still set up but will not contain an offset.
*/
static int i2c_setup_offset(struct dm_i2c_chip *chip, uint offset,
uint8_t offset_buf[], struct i2c_msg *msg)
{
int offset_len;
msg->addr = chip->chip_addr;
msg->flags = chip->flags & DM_I2C_CHIP_10BIT ? I2C_M_TEN : 0;
msg->len = chip->offset_len;
msg->buf = offset_buf;
if (!chip->offset_len)
return -EADDRNOTAVAIL;
assert(chip->offset_len <= I2C_MAX_OFFSET_LEN);
offset_len = chip->offset_len;
while (offset_len--)
*offset_buf++ = offset >> (8 * offset_len);
return 0;
}
static int i2c_read_bytewise(struct udevice *dev, uint offset,
uint8_t *buffer, int len)
{
struct dm_i2c_chip *chip = dev_get_parentdata(dev);
struct udevice *bus = dev_get_parent(dev);
struct dm_i2c_ops *ops = i2c_get_ops(bus);
struct i2c_msg msg[2], *ptr;
uint8_t offset_buf[I2C_MAX_OFFSET_LEN];
int ret;
int i;
for (i = 0; i < len; i++) {
if (i2c_setup_offset(chip, offset + i, offset_buf, msg))
return -EINVAL;
ptr = msg + 1;
ptr->addr = chip->chip_addr;
ptr->flags = msg->flags | I2C_M_RD;
ptr->len = 1;
ptr->buf = &buffer[i];
ptr++;
ret = ops->xfer(bus, msg, ptr - msg);
if (ret)
return ret;
}
return 0;
}
static int i2c_write_bytewise(struct udevice *dev, uint offset,
const uint8_t *buffer, int len)
{
struct dm_i2c_chip *chip = dev_get_parentdata(dev);
struct udevice *bus = dev_get_parent(dev);
struct dm_i2c_ops *ops = i2c_get_ops(bus);
struct i2c_msg msg[1];
uint8_t buf[I2C_MAX_OFFSET_LEN + 1];
int ret;
int i;
for (i = 0; i < len; i++) {
if (i2c_setup_offset(chip, offset + i, buf, msg))
return -EINVAL;
buf[msg->len++] = buffer[i];
ret = ops->xfer(bus, msg, 1);
if (ret)
return ret;
}
return 0;
}
int i2c_read(struct udevice *dev, uint offset, uint8_t *buffer, int len)
{
struct dm_i2c_chip *chip = dev_get_parentdata(dev);
struct udevice *bus = dev_get_parent(dev);
struct dm_i2c_ops *ops = i2c_get_ops(bus);
struct i2c_msg msg[2], *ptr;
uint8_t offset_buf[I2C_MAX_OFFSET_LEN];
int msg_count;
if (!ops->xfer)
return -ENOSYS;
if (chip->flags & DM_I2C_CHIP_RD_ADDRESS)
return i2c_read_bytewise(dev, offset, buffer, len);
ptr = msg;
if (!i2c_setup_offset(chip, offset, offset_buf, ptr))
ptr++;
if (len) {
ptr->addr = chip->chip_addr;
ptr->flags = chip->flags & DM_I2C_CHIP_10BIT ? I2C_M_TEN : 0;
ptr->flags |= I2C_M_RD;
ptr->len = len;
ptr->buf = buffer;
ptr++;
}
msg_count = ptr - msg;
return ops->xfer(bus, msg, msg_count);
}
int i2c_write(struct udevice *dev, uint offset, const uint8_t *buffer, int len)
{
struct dm_i2c_chip *chip = dev_get_parentdata(dev);
struct udevice *bus = dev_get_parent(dev);
struct dm_i2c_ops *ops = i2c_get_ops(bus);
struct i2c_msg msg[1];
if (!ops->xfer)
return -ENOSYS;
if (chip->flags & DM_I2C_CHIP_WR_ADDRESS)
return i2c_write_bytewise(dev, offset, buffer, len);
/*
* The simple approach would be to send two messages here: one to
* set the offset and one to write the bytes. However some drivers
* will not be expecting this, and some chips won't like how the
* driver presents this on the I2C bus.
*
* The API does not support separate offset and data. We could extend
* it with a flag indicating that there is data in the next message
* that needs to be processed in the same transaction. We could
* instead add an additional buffer to each message. For now, handle
* this in the uclass since it isn't clear what the impact on drivers
* would be with this extra complication. Unfortunately this means
* copying the message.
*
* Use the stack for small messages, malloc() for larger ones. We
* need to allow space for the offset (up to 4 bytes) and the message
* itself.
*/
if (len < 64) {
uint8_t buf[I2C_MAX_OFFSET_LEN + len];
i2c_setup_offset(chip, offset, buf, msg);
msg->len += len;
memcpy(buf + chip->offset_len, buffer, len);
return ops->xfer(bus, msg, 1);
} else {
uint8_t *buf;
int ret;
buf = malloc(I2C_MAX_OFFSET_LEN + len);
if (!buf)
return -ENOMEM;
i2c_setup_offset(chip, offset, buf, msg);
msg->len += len;
memcpy(buf + chip->offset_len, buffer, len);
ret = ops->xfer(bus, msg, 1);
free(buf);
return ret;
}
}
/**
* i2c_probe_chip() - probe for a chip on a bus
*
* @bus: Bus to probe
* @chip_addr: Chip address to probe
* @flags: Flags for the chip
* @return 0 if found, -ENOSYS if the driver is invalid, -EREMOTEIO if the chip
* does not respond to probe
*/
static int i2c_probe_chip(struct udevice *bus, uint chip_addr,
enum dm_i2c_chip_flags chip_flags)
{
struct dm_i2c_ops *ops = i2c_get_ops(bus);
struct i2c_msg msg[1];
int ret;
if (ops->probe_chip) {
ret = ops->probe_chip(bus, chip_addr, chip_flags);
if (!ret || ret != -ENOSYS)
return ret;
}
if (!ops->xfer)
return -ENOSYS;
/* Probe with a zero-length message */
msg->addr = chip_addr;
msg->flags = chip_flags & DM_I2C_CHIP_10BIT ? I2C_M_TEN : 0;
msg->len = 0;
msg->buf = NULL;
return ops->xfer(bus, msg, 1);
}
static int i2c_bind_driver(struct udevice *bus, uint chip_addr,
struct udevice **devp)
{
struct dm_i2c_chip chip;
char name[30], *str;
struct udevice *dev;
int ret;
snprintf(name, sizeof(name), "generic_%x", chip_addr);
str = strdup(name);
ret = device_bind_driver(bus, "i2c_generic_chip_drv", str, &dev);
debug("%s: device_bind_driver: ret=%d\n", __func__, ret);
if (ret)
goto err_bind;
/* Tell the device what we know about it */
memset(&chip, '\0', sizeof(chip));
chip.chip_addr = chip_addr;
chip.offset_len = 1; /* we assume */
ret = device_probe_child(dev, &chip);
debug("%s: device_probe_child: ret=%d\n", __func__, ret);
if (ret)
goto err_probe;
*devp = dev;
return 0;
err_probe:
device_unbind(dev);
err_bind:
free(str);
return ret;
}
int i2c_get_chip(struct udevice *bus, uint chip_addr, struct udevice **devp)
{
struct udevice *dev;
debug("%s: Searching bus '%s' for address %02x: ", __func__,
bus->name, chip_addr);
for (device_find_first_child(bus, &dev); dev;
device_find_next_child(&dev)) {
struct dm_i2c_chip store;
struct dm_i2c_chip *chip = dev_get_parentdata(dev);
int ret;
if (!chip) {
chip = &store;
i2c_chip_ofdata_to_platdata(gd->fdt_blob,
dev->of_offset, chip);
}
if (chip->chip_addr == chip_addr) {
ret = device_probe(dev);
debug("found, ret=%d\n", ret);
if (ret)
return ret;
*devp = dev;
return 0;
}
}
debug("not found\n");
return i2c_bind_driver(bus, chip_addr, devp);
}
int i2c_get_chip_for_busnum(int busnum, int chip_addr, struct udevice **devp)
{
struct udevice *bus;
int ret;
ret = uclass_get_device_by_seq(UCLASS_I2C, busnum, &bus);
if (ret) {
debug("Cannot find I2C bus %d\n", busnum);
return ret;
}
ret = i2c_get_chip(bus, chip_addr, devp);
if (ret) {
debug("Cannot find I2C chip %02x on bus %d\n", chip_addr,
busnum);
return ret;
}
return 0;
}
int i2c_probe(struct udevice *bus, uint chip_addr, uint chip_flags,
struct udevice **devp)
{
int ret;
*devp = NULL;
/* First probe that chip */
ret = i2c_probe_chip(bus, chip_addr, chip_flags);
debug("%s: bus='%s', address %02x, ret=%d\n", __func__, bus->name,
chip_addr, ret);
if (ret)
return ret;
/* The chip was found, see if we have a driver, and probe it */
ret = i2c_get_chip(bus, chip_addr, devp);
debug("%s: i2c_get_chip: ret=%d\n", __func__, ret);
return ret;
}
int i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
{
struct dm_i2c_ops *ops = i2c_get_ops(bus);
struct dm_i2c_bus *i2c = bus->uclass_priv;
int ret;
/*
* If we have a method, call it. If not then the driver probably wants
* to deal with speed changes on the next transfer. It can easily read
* the current speed from this uclass
*/
if (ops->set_bus_speed) {
ret = ops->set_bus_speed(bus, speed);
if (ret)
return ret;
}
i2c->speed_hz = speed;
return 0;
}
/*
* i2c_get_bus_speed:
*
* Returns speed of selected I2C bus in Hz
*/
int i2c_get_bus_speed(struct udevice *bus)
{
struct dm_i2c_ops *ops = i2c_get_ops(bus);
struct dm_i2c_bus *i2c = bus->uclass_priv;
if (!ops->get_bus_speed)
return i2c->speed_hz;
return ops->get_bus_speed(bus);
}
int i2c_set_chip_flags(struct udevice *dev, uint flags)
{
struct udevice *bus = dev->parent;
struct dm_i2c_chip *chip = dev_get_parentdata(dev);
struct dm_i2c_ops *ops = i2c_get_ops(bus);
int ret;
if (ops->set_flags) {
ret = ops->set_flags(dev, flags);
if (ret)
return ret;
}
chip->flags = flags;
return 0;
}
int i2c_get_chip_flags(struct udevice *dev, uint *flagsp)
{
struct dm_i2c_chip *chip = dev_get_parentdata(dev);
*flagsp = chip->flags;
return 0;
}
int i2c_set_chip_offset_len(struct udevice *dev, uint offset_len)
{
struct dm_i2c_chip *chip = dev_get_parentdata(dev);
if (offset_len > I2C_MAX_OFFSET_LEN)
return -EINVAL;
chip->offset_len = offset_len;
return 0;
}
int i2c_deblock(struct udevice *bus)
{
struct dm_i2c_ops *ops = i2c_get_ops(bus);
/*
* We could implement a software deblocking here if we could get
* access to the GPIOs used by I2C, and switch them to GPIO mode
* and then back to I2C. This is somewhat beyond our powers in
* driver model at present, so for now just fail.
*
* See https://patchwork.ozlabs.org/patch/399040/
*/
if (!ops->deblock)
return -ENOSYS;
return ops->deblock(bus);
}
int i2c_chip_ofdata_to_platdata(const void *blob, int node,
struct dm_i2c_chip *chip)
{
chip->offset_len = 1; /* default */
chip->flags = 0;
chip->chip_addr = fdtdec_get_int(gd->fdt_blob, node, "reg", -1);
if (chip->chip_addr == -1) {
debug("%s: I2C Node '%s' has no 'reg' property\n", __func__,
fdt_get_name(blob, node, NULL));
return -EINVAL;
}
return 0;
}
static int i2c_post_probe(struct udevice *dev)
{
struct dm_i2c_bus *i2c = dev->uclass_priv;
i2c->speed_hz = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
"clock-frequency", 100000);
return i2c_set_bus_speed(dev, i2c->speed_hz);
}
int i2c_post_bind(struct udevice *dev)
{
/* Scan the bus for devices */
return dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset, false);
}
UCLASS_DRIVER(i2c) = {
.id = UCLASS_I2C,
.name = "i2c",
.per_device_auto_alloc_size = sizeof(struct dm_i2c_bus),
.post_bind = i2c_post_bind,
.post_probe = i2c_post_probe,
};
UCLASS_DRIVER(i2c_generic) = {
.id = UCLASS_I2C_GENERIC,
.name = "i2c_generic",
};
U_BOOT_DRIVER(i2c_generic_chip_drv) = {
.name = "i2c_generic_chip_drv",
.id = UCLASS_I2C_GENERIC,
};