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 Signed-off-by: Simon Glass sjg@chromium.org ---
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 | 457 +++++++++++++++++++++++++++++++++++++++++++++ include/config_fallbacks.h | 6 + include/dm/uclass-id.h | 2 + include/i2c.h | 349 ++++++++++++++++++++++++++++++++++ 5 files changed, 815 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..e5a50eb --- /dev/null +++ b/drivers/i2c/i2c-uclass.c @@ -0,0 +1,457 @@ +/* + * 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; + 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_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 & 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_RE_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; + } +} + +static int i2c_probe_chip(struct udevice *bus, uint chip_addr, + enum dm_i2c_chip_flags flags) +{ + struct dm_i2c_ops *ops = i2c_get_ops(bus); + struct i2c_msg msg[1]; + uint8_t ch = 0; + int ret; + + if (ops->probe_chip) { + ret = ops->probe_chip(bus, chip_addr, flags); + if (!ret || ret != -ENOSYS) + return ret; + } + + if (!ops->xfer) + return -ENOSYS; + + /* Probe with a zero-length message */ + msg->addr = chip_addr; + msg->flags = 0; + msg->len = 0; + 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_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->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 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..943490e 100644 --- a/include/i2c.h +++ b/include/i2c.h @@ -18,6 +18,352 @@ #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) + * @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 + * @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 + * @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, + * 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, -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. This method is optional. + * + * @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 +797,7 @@ 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_ */