[U-Boot] [PATCH v3 01/10] dm: i2c: Add a uclass for I2C
Simon Glass
sjg at chromium.org
Fri Nov 28 05:47:07 CET 2014
+Masahiro
On Nov 24, 2014 11:58 AM, "Simon Glass" <sjg at chromium.org> wrote:
> 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
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
> Changes in v3:
> - 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()
> - Add a helper to query chip flags
> - Add support for reading a byte at a time with an address for each byte
>
> Changes in v2:
> - 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
> - Add some debugging for generic I2C device binding
> - 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
>
> drivers/i2c/Makefile | 1 +
> drivers/i2c/i2c-uclass.c | 411
> +++++++++++++++++++++++++++++++++++++++++++++
> include/config_fallbacks.h | 6 +
> include/dm/uclass-id.h | 2 +
> include/i2c.h | 348 ++++++++++++++++++++++++++++++++++++++
> 5 files changed, 768 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..4063a80
> --- /dev/null
> +++ b/drivers/i2c/i2c-uclass.c
> @@ -0,0 +1,411 @@
> +/*
> + * 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;
> +
> +static bool i2c_setup_offset(struct dm_i2c_chip *chip, uint offset,
> + uint8_t offset_buf[], struct i2c_msg *msg)
> +{
> + if (!chip->offset_len)
> + return false;
> + msg->addr = chip->chip_addr;
> + msg->flags = chip->flags;
> + msg->len = chip->offset_len;
> + msg->buf = offset_buf;
> + offset_buf[0] = offset;
> + offset_buf[1] = offset >> 8;
> + offset_buf[2] = offset >> 16;
> + offset_buf[3] = offset >> 24;
> +
> + return true;
> +}
> +
> +static int i2c_read_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[5];
> + int ret;
> + int i;
> +
> + for (i = 0; i < len; i++) {
> + i2c_setup_offset(chip, offset, buf, msg);
> + msg->len++;
> + buf[chip->offset_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[4];
> + int msg_count;
> +
> + if (!ops->xfer)
> + return -ENOSYS;
> + if (chip->flags & DM_I2C_CHIP_RE_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 | 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;
> +
> + /*
> + * 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[4 + 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(4 + 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;
> + }
> +}
> +
> +static int i2c_probe_chip(struct udevice *bus, uint chip_addr)
> +{
> + struct dm_i2c_ops *ops = i2c_get_ops(bus);
> + struct i2c_msg msg[1];
> + uint8_t ch = 0;
> +
> + if (!ops->xfer)
> + return -ENOSYS;
> +
> + msg->addr = chip_addr;
> + msg->flags = 0;
> + msg->len = 1;
> + msg->buf = &ch;
> +
> + 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_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 */
> + chip = calloc(1, sizeof(struct dm_i2c_chip));
> + if (!chip) {
> + ret = -ENOMEM;
> + goto err_mem;
> + }
> + 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);
> + free(chip);
> + if (ret)
> + goto err_probe;
> +
> + *devp = dev;
> + return 0;
> +
> +err_probe:
> +err_mem:
> + 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, struct udevice **devp)
> +{
> + int ret;
> +
> + *devp = NULL;
> +
> + /* First probe that chip */
> + ret = i2c_probe_chip(bus, chip_addr);
> + 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 (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->set_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 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 (offset_len > 3)
> + return -EINVAL;
> + if (ops->set_offset_len) {
> + ret = ops->set_offset_len(dev, offset_len);
> + if (ret)
> + return ret;
> + }
> + 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_drv) = {
> + .name = "i2c_generic_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 a8944c9..43514bc 100644
> --- a/include/dm/uclass-id.h
> +++ b/include/dm/uclass-id.h
> @@ -28,6 +28,8 @@ enum uclass_id {
> UCLASS_SPI_GENERIC, /* Generic SPI flash target */
> UCLASS_SPI_FLASH, /* SPI flash */
> UCLASS_CROS_EC, /* Chrome OS EC */
> + 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..dd8fd2e 100644
> --- a/include/i2c.h
> +++ b/include/i2c.h
> @@ -18,6 +18,351 @@
> #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_RE_ADDRESS = 1 << 1, /* Send address for every 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)
> + * @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, 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
> + * @buf: Buffer to send/receive
> + */
> +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
> + * @chip_addr: Chip address to read from
> + * @offset: Offset within chip to start reading
> + * @olen: Length of chip offset in bytes
> + * @buffer: Place to put data
> + * @len: Number of bytes to read
> + * @return 0 if OK, -EREMOTEIO if the slave did not ACK a byte,
> + * other -ve value on some other error
> + */
> + int (*xfer)(struct udevice *bus, struct i2c_msg *msg, int nmsgs);
> +
> + /**
> + * 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.
> + *
> + * @bus: Bus to adjust
> + * @speed: Requested speed in Hz
> + * @return 0 if OK, -INVAL 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.
> + *
> + * @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.
> + * 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);
> +
> + /**
> + * set_offset_len() - set the offset length of a chip (optional)
> + *
> + * This is generally implemented by the uclass, but drivers can
> + * check the value to ensure that unsupported options are not used.
> + * If provided, this method will always be called when the offset
> + * length changes from the default of 1.
> + *
> + * @dev: Chip to adjust
> + * @addr_len: New offset length value (typically 1 or 2)
> + * @return 0 if OK, -INVAL if value is unsupported
> + */
> + int (*set_offset_len)(struct udevice *dev, uint offset_len);
> +
> + /**
> + * 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 +796,7 @@ 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_ */
> --
> 2.1.0.rc2.206.gedb03e5
>
>
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