--- /dev/null
+/*
+ * Copyright (c) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <i2c.h>
+#include <dm/lists.h>
+#include <dm/root.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * struct i2c_mux: Information the uclass stores about an I2C mux
+ *
+ * @selected: Currently selected mux, or -1 for none
+ * @i2c_bus: I2C bus to use for communcation
+ */
+struct i2c_mux {
+ int selected;
+ struct udevice *i2c_bus;
+};
+
+/**
+ * struct i2c_mux_bus: Information about each bus the mux controls
+ *
+ * @channel: Channel number used to select this bus
+ */
+struct i2c_mux_bus {
+ uint channel;
+};
+
+/* Find out the mux channel number */
+static int i2c_mux_child_post_bind(struct udevice *dev)
+{
+ struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
+ int channel;
+
+ channel = fdtdec_get_int(gd->fdt_blob, dev->of_offset, "reg", -1);
+ if (channel < 0)
+ return -EINVAL;
+ plat->channel = channel;
+
+ return 0;
+}
+
+/* Find the I2C buses selected by this mux */
+static int i2c_mux_post_bind(struct udevice *mux)
+{
+ const void *blob = gd->fdt_blob;
+ int ret;
+ int offset;
+
+ debug("%s: %s\n", __func__, mux->name);
+ /*
+ * There is no compatible string in the sub-nodes, so we must manually
+ * bind these
+ */
+ for (offset = fdt_first_subnode(blob, mux->of_offset);
+ offset > 0;
+ offset = fdt_next_subnode(blob, offset)) {
+ struct udevice *dev;
+ const char *name;
+
+ name = fdt_get_name(blob, offset, NULL);
+ ret = device_bind_driver_to_node(mux, "i2c_mux_bus_drv", name,
+ offset, &dev);
+ debug(" - bind ret=%d, %s\n", ret, dev ? dev->name : NULL);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+/* Set up the mux ready for use */
+static int i2c_mux_post_probe(struct udevice *mux)
+{
+ struct i2c_mux *priv = dev_get_uclass_priv(mux);
+ int ret;
+
+ debug("%s: %s\n", __func__, mux->name);
+ priv->selected = -1;
+
+ ret = uclass_get_device_by_phandle(UCLASS_I2C, mux, "i2c-parent",
+ &priv->i2c_bus);
+ if (ret)
+ return ret;
+ debug("%s: bus=%p/%s\n", __func__, priv->i2c_bus, priv->i2c_bus->name);
+
+ return 0;
+}
+
+int i2c_mux_select(struct udevice *dev)
+{
+ struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
+ struct udevice *mux = dev->parent;
+ struct i2c_mux_ops *ops = i2c_mux_get_ops(mux);
+
+ if (!ops->select)
+ return -ENOSYS;
+
+ return ops->select(mux, dev, plat->channel);
+}
+
+int i2c_mux_deselect(struct udevice *dev)
+{
+ struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
+ struct udevice *mux = dev->parent;
+ struct i2c_mux_ops *ops = i2c_mux_get_ops(mux);
+
+ if (!ops->deselect)
+ return -ENOSYS;
+
+ return ops->deselect(mux, dev, plat->channel);
+}
+
+static int i2c_mux_bus_set_bus_speed(struct udevice *dev, unsigned int speed)
+{
+ struct udevice *mux = dev->parent;
+ struct i2c_mux *priv = dev_get_uclass_priv(mux);
+ int ret, ret2;
+
+ ret = i2c_mux_select(dev);
+ if (ret)
+ return ret;
+ ret = dm_i2c_set_bus_speed(priv->i2c_bus, speed);
+ ret2 = i2c_mux_deselect(dev);
+
+ return ret ? ret : ret2;
+}
+
+static int i2c_mux_bus_probe(struct udevice *dev, uint chip_addr,
+ uint chip_flags)
+{
+ struct udevice *mux = dev->parent;
+ struct i2c_mux *priv = dev_get_uclass_priv(mux);
+ struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus);
+ int ret, ret2;
+
+ debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name);
+ if (!ops->probe_chip)
+ return -ENOSYS;
+ ret = i2c_mux_select(dev);
+ if (ret)
+ return ret;
+ ret = ops->probe_chip(priv->i2c_bus, chip_addr, chip_flags);
+ ret2 = i2c_mux_deselect(dev);
+
+ return ret ? ret : ret2;
+}
+
+static int i2c_mux_bus_xfer(struct udevice *dev, struct i2c_msg *msg,
+ int nmsgs)
+{
+ struct udevice *mux = dev->parent;
+ struct i2c_mux *priv = dev_get_uclass_priv(mux);
+ struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus);
+ int ret, ret2;
+
+ debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name);
+ if (!ops->xfer)
+ return -ENOSYS;
+ ret = i2c_mux_select(dev);
+ if (ret)
+ return ret;
+ ret = ops->xfer(priv->i2c_bus, msg, nmsgs);
+ ret2 = i2c_mux_deselect(dev);
+
+ return ret ? ret : ret2;
+}
+
+static const struct dm_i2c_ops i2c_mux_bus_ops = {
+ .xfer = i2c_mux_bus_xfer,
+ .probe_chip = i2c_mux_bus_probe,
+ .set_bus_speed = i2c_mux_bus_set_bus_speed,
+};
+
+U_BOOT_DRIVER(i2c_mux_bus) = {
+ .name = "i2c_mux_bus_drv",
+ .id = UCLASS_I2C,
+ .per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
+ .ops = &i2c_mux_bus_ops,
+};
+
+UCLASS_DRIVER(i2c_mux) = {
+ .id = UCLASS_I2C_MUX,
+ .name = "i2c_mux",
+ .post_bind = i2c_mux_post_bind,
+ .post_probe = i2c_mux_post_probe,
+ .per_device_auto_alloc_size = sizeof(struct i2c_mux),
+ .per_child_platdata_auto_alloc_size = sizeof(struct i2c_mux_bus),
+ .child_post_bind = i2c_mux_child_post_bind,
+};
#define i2c_get_ops(dev) ((struct dm_i2c_ops *)(dev)->driver->ops)
+/**
+ * struct i2c_mux_ops - operations for an I2C mux
+ *
+ * The current mux state is expected to be stored in the mux itself since
+ * it is the only thing that knows how to make things work. The mux can
+ * record the current state and then avoid switching unless it is necessary.
+ * So select() can be skipped if the mux is already in the correct state.
+ * Also deselect() can be made a nop if required.
+ */
+struct i2c_mux_ops {
+ /**
+ * select() - select one of of I2C buses attached to a mux
+ *
+ * This will be called when there is no bus currently selected by the
+ * mux. This method does not need to deselect the old bus since
+ * deselect() will be already have been called if necessary.
+ *
+ * @mux: Mux device
+ * @bus: I2C bus to select
+ * @channel: Channel number correponding to the bus to select
+ * @return 0 if OK, -ve on error
+ */
+ int (*select)(struct udevice *mux, struct udevice *bus, uint channel);
+
+ /**
+ * deselect() - select one of of I2C buses attached to a mux
+ *
+ * This is used to deselect the currently selected I2C bus.
+ *
+ * @mux: Mux device
+ * @bus: I2C bus to deselect
+ * @channel: Channel number correponding to the bus to deselect
+ * @return 0 if OK, -ve on error
+ */
+ int (*deselect)(struct udevice *mux, struct udevice *bus, uint channel);
+};
+
+#define i2c_mux_get_ops(dev) ((struct i2c_mux_ops *)(dev)->driver->ops)
+
/**
* i2c_get_chip() - get a device to use to access a chip on a bus
*
projects / karo-tx-uboot.git / commitdiff