[U-Boot] [PATCH v6 01/11] dm: i2c: Add a uclass for I2C
Simon Glass
sjg at chromium.org
Wed Dec 10 16:55:47 CET 2014
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 at denx.de>
Reviewed-by: Masahiro Yamada <yamada.m at jp.panasonic.com>
Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v6: None
Changes in v5:
- Add a function comment for i2c_probe_chip()
- Add an assert for offset_len in i2c_setup_offset()
- Add more detail to return value comment on get_buf_speed()
- Add more detail to return value comment on xfer() method
- Fix -INVAL typo
- Make i2c_get_bus_speed() independent of i2c_set_bus_speed()
- Split DM_I2C_CHIP_RD_ADDRESS into read and write varaints
- Update comments in struct i2c_msg to allow buf to be NULL
- Use a NULL buffer in i2c_probe_chip()
Changes in v4:
- Add a constant for I2C_MAX_OFFSET_LEN
- Add a probe_chip() method to the uclass
- Add chip flags to i2c_probe()
- Add comment to i2c_setup_offset()
- Add comments to indicate which methods are optional
- Add comments to set_bus_speed() method
- Adjust i2c_bind_driver() to avoid calloc()/free()
- Drop set_offset_len() method
- Fix copying of chip flags to message in i2c_setup_offset()
- Fix endianness of i2c_setup_offset()
- Fix method comment for xfer()
- Invert return value of i2c_setup_offset()
- Probe with a message length of 0
- Rename i2c_generic_drv to i2c_generic_chip_drv
- Rename i2c_read_bytewise() and implement a real one
Changes in v3:
- Add a helper to query chip flags
- Add support for reading a byte at a time with an address for each byte
- Change uclass <=> driver API to use a message list
- Correct bogus address len code (was confused with chip address length)
- Drop extra call to i2c_bind_driver() in i2c_probe()
Changes in v2:
- Add a 'deblock' method to recover an I2C bus stuck in mid-transaction
- Add a helper function to find a chip on a particular bus number
- Add some debugging for generic I2C device binding
- Fix cihp typo
- Implement generic I2C devices to allow 'i2c probe' on unknown devices
- Return the probed device from i2c_probe()
- Set the bus speed after the bus is probed
drivers/i2c/Makefile | 1 +
drivers/i2c/i2c-uclass.c | 466 +++++++++++++++++++++++++++++++++++++++++++++
include/config_fallbacks.h | 6 +
include/dm/uclass-id.h | 2 +
include/i2c.h | 352 ++++++++++++++++++++++++++++++++++
5 files changed, 827 insertions(+)
create mode 100644 drivers/i2c/i2c-uclass.c
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index dae3d71..063e097 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -4,6 +4,7 @@
#
# SPDX-License-Identifier: GPL-2.0+
#
+obj-$(CONFIG_DM_I2C) += i2c-uclass.o
obj-$(CONFIG_SYS_I2C_ADI) += adi_i2c.o
obj-$(CONFIG_I2C_MV) += mv_i2c.o
diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c
new file mode 100644
index 0000000..005bf86
--- /dev/null
+++ b/drivers/i2c/i2c-uclass.c
@@ -0,0 +1,466 @@
+/*
+ * 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,
+};
diff --git a/include/config_fallbacks.h b/include/config_fallbacks.h
index 7d8daa2..91a0a43 100644
--- a/include/config_fallbacks.h
+++ b/include/config_fallbacks.h
@@ -87,4 +87,10 @@
#undef CONFIG_IMAGE_FORMAT_LEGACY
#endif
+#ifdef CONFIG_DM_I2C
+# ifdef CONFIG_SYS_I2C
+# error "Cannot define CONFIG_SYS_I2C when CONFIG_DM_I2C is used"
+# endif
+#endif
+
#endif /* __CONFIG_FALLBACKS_H */
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 202f59b..01866c3 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -29,6 +29,8 @@ enum uclass_id {
UCLASS_SPI_FLASH, /* SPI flash */
UCLASS_CROS_EC, /* Chrome OS EC */
UCLASS_THERMAL, /* Thermal sensor */
+ UCLASS_I2C, /* I2C bus */
+ UCLASS_I2C_GENERIC, /* Generic I2C device */
UCLASS_COUNT,
UCLASS_INVALID = -1,
diff --git a/include/i2c.h b/include/i2c.h
index 1b4078e..9c6a60c 100644
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -18,6 +18,355 @@
#define _I2C_H_
/*
+ * For now there are essentially two parts to this file - driver model
+ * here at the top, and the older code below (with CONFIG_SYS_I2C being
+ * most recent). The plan is to migrate everything to driver model.
+ * The driver model structures and API are separate as they are different
+ * enough as to be incompatible for compilation purposes.
+ */
+
+#ifdef CONFIG_DM_I2C
+
+enum dm_i2c_chip_flags {
+ DM_I2C_CHIP_10BIT = 1 << 0, /* Use 10-bit addressing */
+ DM_I2C_CHIP_RD_ADDRESS = 1 << 1, /* Send address for each read byte */
+ DM_I2C_CHIP_WR_ADDRESS = 1 << 2, /* Send address for each write byte */
+};
+
+/**
+ * struct dm_i2c_chip - information about an i2c chip
+ *
+ * An I2C chip is a device on the I2C bus. It sits at a particular address
+ * and normally supports 7-bit or 10-bit addressing.
+ *
+ * To obtain this structure, use dev_get_parentdata(dev) where dev is the
+ * chip to examine.
+ *
+ * @chip_addr: Chip address on bus
+ * @offset_len: Length of offset in bytes. A single byte offset can
+ * represent up to 256 bytes. A value larger than 1 may be
+ * needed for larger devices.
+ * @flags: Flags for this chip (dm_i2c_chip_flags)
+ * @emul: Emulator for this chip address (only used for emulation)
+ */
+struct dm_i2c_chip {
+ uint chip_addr;
+ uint offset_len;
+ uint flags;
+#ifdef CONFIG_SANDBOX
+ struct udevice *emul;
+#endif
+};
+
+/**
+ * struct dm_i2c_bus- information about an i2c bus
+ *
+ * An I2C bus contains 0 or more chips on it, each at its own address. The
+ * bus can operate at different speeds (measured in Hz, typically 100KHz
+ * or 400KHz).
+ *
+ * To obtain this structure, use bus->uclass_priv where bus is the I2C
+ * bus udevice.
+ *
+ * @speed_hz: Bus speed in hertz (typically 100000)
+ */
+struct dm_i2c_bus {
+ int speed_hz;
+};
+
+/**
+ * i2c_read() - read bytes from an I2C chip
+ *
+ * To obtain an I2C device (called a 'chip') given the I2C bus address you
+ * can use i2c_get_chip(). To obtain a bus by bus number use
+ * uclass_get_device_by_seq(UCLASS_I2C, <bus number>).
+ *
+ * To set the address length of a devce use i2c_set_addr_len(). It
+ * defaults to 1.
+ *
+ * @dev: Chip to read from
+ * @offset: Offset within chip to start reading
+ * @buffer: Place to put data
+ * @len: Number of bytes to read
+ *
+ * @return 0 on success, -ve on failure
+ */
+int i2c_read(struct udevice *dev, uint offset, uint8_t *buffer,
+ int len);
+
+/**
+ * i2c_write() - write bytes to an I2C chip
+ *
+ * See notes for i2c_read() above.
+ *
+ * @dev: Chip to write to
+ * @offset: Offset within chip to start writing
+ * @buffer: Buffer containing data to write
+ * @len: Number of bytes to write
+ *
+ * @return 0 on success, -ve on failure
+ */
+int i2c_write(struct udevice *dev, uint offset, const uint8_t *buffer,
+ int len);
+
+/**
+ * i2c_probe() - probe a particular chip address
+ *
+ * This can be useful to check for the existence of a chip on the bus.
+ * It is typically implemented by writing the chip address to the bus
+ * and checking that the chip replies with an ACK.
+ *
+ * @bus: Bus to probe
+ * @chip_addr: 7-bit address to probe (10-bit and others are not supported)
+ * @chip_flags: Flags for the probe (see enum dm_i2c_chip_flags)
+ * @devp: Returns the device found, or NULL if none
+ * @return 0 if a chip was found at that address, -ve if not
+ */
+int i2c_probe(struct udevice *bus, uint chip_addr, uint chip_flags,
+ struct udevice **devp);
+
+/**
+ * i2c_set_bus_speed() - set the speed of a bus
+ *
+ * @bus: Bus to adjust
+ * @speed: Requested speed in Hz
+ * @return 0 if OK, -EINVAL for invalid values
+ */
+int i2c_set_bus_speed(struct udevice *bus, unsigned int speed);
+
+/**
+ * i2c_get_bus_speed() - get the speed of a bus
+ *
+ * @bus: Bus to check
+ * @return speed of selected I2C bus in Hz, -ve on error
+ */
+int i2c_get_bus_speed(struct udevice *bus);
+
+/**
+ * i2c_set_chip_flags() - set flags for a chip
+ *
+ * Typically addresses are 7 bits, but for 10-bit addresses you should set
+ * flags to DM_I2C_CHIP_10BIT. All accesses will then use 10-bit addressing.
+ *
+ * @dev: Chip to adjust
+ * @flags: New flags
+ * @return 0 if OK, -EINVAL if value is unsupported, other -ve value on error
+ */
+int i2c_set_chip_flags(struct udevice *dev, uint flags);
+
+/**
+ * i2c_get_chip_flags() - get flags for a chip
+ *
+ * @dev: Chip to check
+ * @flagsp: Place to put flags
+ * @return 0 if OK, other -ve value on error
+ */
+int i2c_get_chip_flags(struct udevice *dev, uint *flagsp);
+
+/**
+ * i2c_set_offset_len() - set the offset length for a chip
+ *
+ * The offset used to access a chip may be up to 4 bytes long. Typically it
+ * is only 1 byte, which is enough for chips with 256 bytes of memory or
+ * registers. The default value is 1, but you can call this function to
+ * change it.
+ *
+ * @offset_len: New offset length value (typically 1 or 2)
+ */
+
+int i2c_set_chip_offset_len(struct udevice *dev, uint offset_len);
+/**
+ * i2c_deblock() - recover a bus that is in an unknown state
+ *
+ * See the deblock() method in 'struct dm_i2c_ops' for full information
+ *
+ * @bus: Bus to recover
+ * @return 0 if OK, -ve on error
+ */
+int i2c_deblock(struct udevice *bus);
+
+/*
+ * Not all of these flags are implemented in the U-Boot API
+ */
+enum dm_i2c_msg_flags {
+ I2C_M_TEN = 0x0010, /* ten-bit chip address */
+ I2C_M_RD = 0x0001, /* read data, from slave to master */
+ I2C_M_STOP = 0x8000, /* send stop after this message */
+ I2C_M_NOSTART = 0x4000, /* no start before this message */
+ I2C_M_REV_DIR_ADDR = 0x2000, /* invert polarity of R/W bit */
+ I2C_M_IGNORE_NAK = 0x1000, /* continue after NAK */
+ I2C_M_NO_RD_ACK = 0x0800, /* skip the Ack bit on reads */
+ I2C_M_RECV_LEN = 0x0400, /* length is first received byte */
+};
+
+/**
+ * struct i2c_msg - an I2C message
+ *
+ * @addr: Slave address
+ * @flags: Flags (see enum dm_i2c_msg_flags)
+ * @len: Length of buffer in bytes, may be 0 for a probe
+ * @buf: Buffer to send/receive, or NULL if no data
+ */
+struct i2c_msg {
+ uint addr;
+ uint flags;
+ uint len;
+ u8 *buf;
+};
+
+/**
+ * struct i2c_msg_list - a list of I2C messages
+ *
+ * This is called i2c_rdwr_ioctl_data in Linux but the name does not seem
+ * appropriate in U-Boot.
+ *
+ * @msg: Pointer to i2c_msg array
+ * @nmsgs: Number of elements in the array
+ */
+struct i2c_msg_list {
+ struct i2c_msg *msgs;
+ uint nmsgs;
+};
+
+/**
+ * struct dm_i2c_ops - driver operations for I2C uclass
+ *
+ * Drivers should support these operations unless otherwise noted. These
+ * operations are intended to be used by uclass code, not directly from
+ * other code.
+ */
+struct dm_i2c_ops {
+ /**
+ * xfer() - transfer a list of I2C messages
+ *
+ * @bus: Bus to read from
+ * @msg: List of messages to transfer
+ * @nmsgs: Number of messages in the list
+ * @return 0 if OK, -EREMOTEIO if the slave did not ACK a byte,
+ * -ECOMM if the speed cannot be supported, -EPROTO if the chip
+ * flags cannot be supported, other -ve value on some other error
+ */
+ int (*xfer)(struct udevice *bus, struct i2c_msg *msg, int nmsgs);
+
+ /**
+ * probe_chip() - probe for the presense of a chip address
+ *
+ * This function is optional. If omitted, the uclass will send a zero
+ * length message instead.
+ *
+ * @bus: Bus to probe
+ * @chip_addr: Chip address to probe
+ * @chip_flags: Probe flags (enum dm_i2c_chip_flags)
+ * @return 0 if chip was found, -EREMOTEIO if not, -ENOSYS to fall back
+ * to default probem other -ve value on error
+ */
+ int (*probe_chip)(struct udevice *bus, uint chip_addr, uint chip_flags);
+
+ /**
+ * set_bus_speed() - set the speed of a bus (optional)
+ *
+ * The bus speed value will be updated by the uclass if this function
+ * does not return an error. This method is optional - if it is not
+ * provided then the driver can read the speed from
+ * bus->uclass_priv->speed_hz
+ *
+ * @bus: Bus to adjust
+ * @speed: Requested speed in Hz
+ * @return 0 if OK, -EINVAL for invalid values
+ */
+ int (*set_bus_speed)(struct udevice *bus, unsigned int speed);
+
+ /**
+ * get_bus_speed() - get the speed of a bus (optional)
+ *
+ * Normally this can be provided by the uclass, but if you want your
+ * driver to check the bus speed by looking at the hardware, you can
+ * implement that here. This method is optional. This method would
+ * normally be expected to return bus->uclass_priv->speed_hz.
+ *
+ * @bus: Bus to check
+ * @return speed of selected I2C bus in Hz, -ve on error
+ */
+ int (*get_bus_speed)(struct udevice *bus);
+
+ /**
+ * set_flags() - set the flags for a chip (optional)
+ *
+ * This is generally implemented by the uclass, but drivers can
+ * check the value to ensure that unsupported options are not used.
+ * This method is optional. If provided, this method will always be
+ * called when the flags change.
+ *
+ * @dev: Chip to adjust
+ * @flags: New flags value
+ * @return 0 if OK, -EINVAL if value is unsupported
+ */
+ int (*set_flags)(struct udevice *dev, uint flags);
+
+ /**
+ * deblock() - recover a bus that is in an unknown state
+ *
+ * I2C is a synchronous protocol and resets of the processor in the
+ * middle of an access can block the I2C Bus until a powerdown of
+ * the full unit is done. This is because slaves can be stuck
+ * waiting for addition bus transitions for a transaction that will
+ * never complete. Resetting the I2C master does not help. The only
+ * way is to force the bus through a series of transitions to make
+ * sure that all slaves are done with the transaction. This method
+ * performs this 'deblocking' if support by the driver.
+ *
+ * This method is optional.
+ */
+ int (*deblock)(struct udevice *bus);
+};
+
+#define i2c_get_ops(dev) ((struct dm_i2c_ops *)(dev)->driver->ops)
+
+/**
+ * i2c_get_chip() - get a device to use to access a chip on a bus
+ *
+ * This returns the device for the given chip address. The device can then
+ * be used with calls to i2c_read(), i2c_write(), i2c_probe(), etc.
+ *
+ * @bus: Bus to examine
+ * @chip_addr: Chip address for the new device
+ * @devp: Returns pointer to new device if found or -ENODEV if not
+ * found
+ */
+int i2c_get_chip(struct udevice *bus, uint chip_addr, struct udevice **devp);
+
+/**
+ * i2c_get_chip() - get a device to use to access a chip on a bus number
+ *
+ * This returns the device for the given chip address on a particular bus
+ * number.
+ *
+ * @busnum: Bus number to examine
+ * @chip_addr: Chip address for the new device
+ * @devp: Returns pointer to new device if found or -ENODEV if not
+ * found
+ */
+int i2c_get_chip_for_busnum(int busnum, int chip_addr, struct udevice **devp);
+
+/**
+ * i2c_chip_ofdata_to_platdata() - Decode standard I2C platform data
+ *
+ * This decodes the chip address from a device tree node and puts it into
+ * its dm_i2c_chip structure. This should be called in your driver's
+ * ofdata_to_platdata() method.
+ *
+ * @blob: Device tree blob
+ * @node: Node offset to read from
+ * @spi: Place to put the decoded information
+ */
+int i2c_chip_ofdata_to_platdata(const void *blob, int node,
+ struct dm_i2c_chip *chip);
+
+#endif
+
+#ifndef CONFIG_DM_I2C
+
+/*
* WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
*
* The implementation MUST NOT use static or global variables if the
@@ -451,4 +800,7 @@ int i2c_get_bus_num_fdt(int node);
* @return 0 if port was reset, -1 if not found
*/
int i2c_reset_port_fdt(const void *blob, int node);
+
+#endif /* !CONFIG_DM_I2C */
+
#endif /* _I2C_H_ */
--
2.2.0.rc0.207.ga3a616c
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