diff options
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/Makefile | 1 | ||||
| -rw-r--r-- | drivers/i2c/i2c-uclass.c | 466 |
2 files changed, 467 insertions, 0 deletions
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, +}; |