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>
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,
+};